Nachi Roller Bearing Technical Specs

Precision Rolling Bearings
Precision Rolling Bearings
Table of Contents
Technical Description
1 Bearing Selection
1-1 Bearing Selection Procedure ......................................................... 2
1-2 Examine Bearing Type .................................................................. 3
2 Bearing Life
2-1 Basic Dynamic Load Rating and Rated Life .................................... 4
2-2 Dynamic Equivalent Load.............................................................. 4
2-3 Angular Contact Ball Bearing Load ................................................ 5
2-4 Basic Static Load Rating and Static Equivalent Load ....................... 6
3 Bearing Tolerance
3-1 Radial Bearing Tolerances............................................................. 7
3-2 Tolerances and Permissible Values of Angular Contact
Ball Bearings for Thrust Loads (TAH/TBH Series) ............................ 9
3-3 Tolerances of Cross Tapered Roller Bearings .................................. 9
3-4 Ball Screw Support Bearing (TAB Series) Tolerances ..................... 10
3-5 Tolerances for Ball Screw Support Bearing (TAF Series) ................ 11
3-6 Tolerances for Tapered Bores (Cylindrical Roller Bearings) ............. 11
4 Bearing Arrangement
4-1 Duplex Bearing Features ............................................................ 12
4-2 Mounting and Mounting Symbols ................................................ 13
4-3 Flush Ground Angular Contact Ball Bearings ................................ 13
5 Preload and Rigidity
5-1 Preload Objectives ..................................................................... 14
5-2 Preload Methods........................................................................ 14
5-3 Measuring Preload ..................................................................... 14
5-4 Preload Effect ............................................................................ 15
5-5 Standard Preload and Axial Rigidity ............................................. 16
6 Lubrication
6-1 Purpose of Lubrication ............................................................... 22
6-2 Lubrication Methods................................................................... 22
7 Limiting Speeds
7-1 Limiting Speed Correction .......................................................... 26
8 Shaft and Housing Design
8-1 Shaft and Housing Fit ................................................................. 27
8-2 Recommended Accuracy for Shaft and Housing ........................... 28
8-3 Chamfer Dimension Limits.......................................................... 29
9 Bearing Handling
9-1 Storing and Transporting Bearings ............................................... 30
9-2 Assembling Bearings .................................................................. 30
9-3 Running Test.............................................................................. 34
9-4 Removing Bearings .................................................................... 34
Dimension Tables
Precision Rolling Bearing Types and Designs .................................................................................................................. 37
Angular Contact Ball Bearings Standard Type
38
7900C/7900AC Series ...................................................................................................................... 40
7000C/7000AC Series ...................................................................................................................... 42
7200C/7200AC Series ...................................................................................................................... 44
High-speed Angular Contact Ball Bearings
46
BNH Series ....................................................................................................................................... 48
Thrust Load Angular Contact Ball Bearings
50
TAH Series........................................................................................................................................ 52
TBH Series ....................................................................................................................................... 54
Multiple-row Cylindrical Roller Bearings
56
NN3000 Series ................................................................................................................................. 58
NNU4900 Series ............................................................................................................................... 60
Cross Tapered Roller Bearings
62
XRN Series ....................................................................................................................................... 64
XRG Series ....................................................................................................................................... 66
Ball Screw Support Bearings
68
TAB Series ........................................................................................................................................ 70
TAF Series ........................................................................................................................................ 72
Technical Description
Technical Description
Bearing
Selection
Bearing
Life
Bearing
Tolerance
Bearing
Arrangement
Preload
and
Rigidity
Lubrication
Limiting
Speeds
Shaft and
Housing
Design
Bearing
Handling
Technical Description
1
Bearing Selection
1-1 Bearing Selection Procedure
While it is not easy to select the optimum bearing type and combination,
it is no exaggeration to say that bearing selection is essential in order to
obtain the desired design performance and service life.
While there is no “best” procedure for selecting the optimal bearing,
the designer should consider giving priority to meeting the most critical
requirement of the bearing. Figure 1.1 provides an example of a
procedure based on the establishment of priorities for the required bearing
characteristics.
Performance, operating conditions,
and environmental conditions
demanded of bearings
1-2 Examine Bearing Type
Study of the Bearing
Arrangements and
Bearing Types
Page 3
① Load direction and size
② Speed
③ Noise and torque
④ Horizontal or vertical shaft
⑤ Rigidity
⑥ Axial bearing arrangement
⑦ Installation and removal
⑧ Vibration, shock
3. Bearing Tolerance
Select the degree
of accuracy
Required Dynamic
Load Rating
① Change from ball bearings
to roller bearings.
② Use multiple bearings.
③ Use alternate dimension.
If high rigidity is required increase the preload.
Calculate the required
dynamic load ratings based
on load, rotation speed, and
desired service life.
6. Lubrication
Page 22
Prevent dirt, water, and other foreign
matter from getting inside the bearing.
Grease lubrication
Sealed bearings
Value analysis
(Can standard parts
be used?)
Oil lubrication
No
Page 14
Page 4
Selecting the
lubrication method
Select bearing
dimensions.
① Shaft axial run-out
② Vibration from rotation
③ Rotating speed
5. Preload and Rigidity
Determining Preload
2. Bearing Life
Page 7
Open bearings
Maintenance is not required, since
grease cannot be removed or added.
Countermeasures to keep
dirt out, and to prevent
oil/grease from leaking.
Design that allows
grease replenishment.
Is size within
design limits?
Yes
2-4. Basic Static Load Rating and
Static Equivalent Load Page 6
Basic static load
rating check
No
Consider shaft and
housing accuracy
Is operating load
smaller than static
load rating?
Yes
8-2. Recommended Accuracy for Shaft and Housing Page 28
9. Bearing Handling
7. Limiting Speeds
Page 26
Consider handling
and installation
Review operating
speed
Review
lubrication
method
No
Consider the design
from a maintenance
viewpoint.
Yes
8-1. Shaft and Housing Fit
Page 27
① Outer or inner ring rotation
② Stationary, rotational or
impact loading
③ Shaft and housing materials
④ Fixed or expansion (free)
⑤ Inner ring expansion due to
centrifugal force at high
rotation speeds
Bearing Selection
Consider how to protect bearing from damage
and dirt in the work environment, and use
proper installation tools.
If the bearing service life or grease life is shorter
than the machine service life, create a design that
allows easy bearing replacement or easy grease
replenishment, and define the maintenance interval.
Monitoring equipment can help in predicting service
life through heat and vibration measurements.
Selection of bearing
● Figure 1.1 Bearing Selection Procedure
2
Page 30
If the bearing service life is the same as or greater
than the machine service life, consider a design or
lubrication that does not require maintenance.
Is speed within limits?
Determine fit
Determine if the shaft and housing accuracy is
the same as or close to the bearing accuracy.
NACHI BEARING
Technical Description
1-2 Examine Bearing Type
Factors
Selection guidelines
Allowable space for bearings
● When designing a shaft system, the rigidity and strength of the shaft are important factors. The first step is to determine the shaft
diameter, and the bore diameter.
● Figure 1.2 shows guidelines for the main precision rolling contact bearings types and sizes used in machine tools.
Load (type, direction, magnitude)
● Select the optimum bearing type in accordance with the magnitude of radial and axial load, direction of the load (either one or both
directions), and level (vibration or shock).
● In general, a roller bearing has a greater load rating capacity than a ball bearing.
Rotating speed
● Select the bearing type in accordance with the maximum rotating speed specified for the machine where the bearing is used.
● The limiting speeds of bearings is largely depended on the magnitude of the load applied, running accuracy, cage material, and cage
design. Therefore, careful consideration is necessary.
● In general, angular contact ball bearings or cylindrical roller bearings, which demonstrate minimal temperature rise, are used in highspeed applications.
Bearing
Selection
Bearing
Life
Rigidity
● In order to improve the rigidity of rotational axis, the rigidity of the shaft and housing, as well as the bearing rigidity become important.
● In general, roller bearing rigidity is greater than a ball bearing.
● The rigidity of combination angular contact ball bearing is increased by applying a preload to the bearing.
Bearing
Tolerance
Mounting and dismounting
● Selecting a separable bearing increases work efficiency during mounting and dismounting for periodic inspection, etc.
Bearing
Arrangement
Preload
and
Rigidity
Lubrication
Limiting
Speeds
79 Series
NNU49 Series
70 Series
BNH Series
NN30 Series
TAH Series
Shaft and
Housing
Design
72 Series
● Figure 1.2 Main Precision Rolling Bearings Used in Machine Tools
Bearing
Handling
Bearing Selection
3
Technical Description
2
Bearing Life
2-1 Basic Dynamic Load Rating and Rated Life
Although the requirements of rolling contact bearings vary somewhat
with the individual application, the principal requirements are:
● High load capabilities
● Low friction
● Smooth and quiet rotation
● High accuracy
● High rigidity
The reliability or durability requirement sets the time frame over
which all other requirements are to be maintained. The reliability
requirement (life in the broad sense) includes grease and acoustic
life, as well as fatigue life. Reliability is reduced by various type of
damage and degradation.
Though there are other damage such as breakage and seizure, these
are considered to be separate from bearing life. Improper handling,
mounting, lubrication, and fits are the major causes of problems
leading to lower-than-calculated bearing life.
Regardless of how well they are maintained or mounted or handled,
dynamic bearings will eventually fail from rolling fatigue generated by
the repetitive stress of bearing load. The service life of a bearing can
be examined from two perspectives: 1) If, from inspection, a trace of
fatigue becomes noticeable, the bearing should be deemed not suitable
for further use; or 2) length of bearing life in hours or revolutions can
be predefined as a limit beyond which the bearing is automatically
replaced. Since calculated fatigue life will vary with the size and type
of bearings used under identical load conditions, great care must be
taken in the analysis of the load conditions and the final choice of
bearings to satisfy the application requirements.
Fatigue lives of individual bearing are dispersed. When a group of
identical bearings operates under the same conditions, the statistical
phenomenon of dispersion will appear. Use of average life is not an
adequate criterion for selecting rolling contact bearings. Instead, it is
more appropriate to consider the limit (hours or numbers of revolutions)
which a large percentage of the operating bearings can attain.
Accordingly, the rating life and basic dynamic load rating Cr or Ca
are defined using the following definition:
● Basic Rating Life
Total number of revolutions that 90% of a group of identical
bearings operated individually under equal conditions can complete
without suffering material damage from rolling fatigue.
● Basic Dynamic Load Rating (Cr or Ca)
Bearing load of constant direction and magnitude that ends the
bearing life after one million revolutions.
The rating life of bearings is calculated by Formula 2.1 and Formula
2.2.
(Formula 2.1)
(Formula 2.2)
: Basic rating life (106 revolutions)
: Basic rating life (hours)
: Basic Dynamic Load Rating (N) (Cr for radial bearings, Ca for thrust bearings)
: Bearing Load (Dynamic Equivalent Load) (N) (Pr for radial bearings, Pa for
thrust bearings)
p : 3 (ball bearings), 10/3 (roller bearings)
N : RPM: (min-1)
L
Lh
C
P
In the case of multiple rows of radial ball bearing arrangements, the
basic dynamic load rating is calculated using the factors provided
below.
2-row arrangement
3-row arrangement
4-row arrangement
1.62
2.16
2.64
2-2 Dynamic Equivalent Load
Bearing load P in Formula 2.1 and Formula 2.2 is the pure radial load
(pure axial load) of constant direction and magnitude. Under actual
operating conditions, there are many cases where radial and axial
loads are applied simultaneously. In such cases, bearing life must
be calculated by converting the radial and axial loads into dynamic
equivalent load.
Dynamic equivalent load is calculated using Formula 2.3.
Bearing load of constant direction and magnitude that ends the
bearing life after one million revolutions.
The rating life of bearings is calculated by Formula 2.1 and Formula
2.2.
● Table 2.1 Load Factors
Nominal
contact
angle
15°
Radial ball
bearings
(Formula 2.3)
Pr
Pa
Fr
Fa
X
Y
4
: Dynamic equivalent radial load (N)
: Dynamic equivalent axial load (N)
: Radial load (N)
: Axial load (N)
: Radial load factors (Table 2.1)
: Axial load factors (Table 2.1)
Bearing Life
Thrust ball
bearings
25°
30°
40°
50°
55°
60°
iFa/
Cor
e
0.015
0.029
0.058
0.087
0.12
0.17
0.29
0.44
0.58
−
−
−
−
−
−
0.38
0.40
0.43
0.46
0.47
0.50
0.55
0.56
0.56
0.68
0.80
1.14
1.49
1.79
2.17
Single-row/singledirection bearing
Fa/Fr>e
X
Y
0.44
0.41
0.39
0.35
0.73
0.81
0.92
1.47
1.40
1.30
1.23
1.19
1.12
1.02
1.00
1.00
0.87
0.76
0.57
1
1
1
Multiple-row/multiple-direction
bearing
Fa/Frde
Fa/Fr>e
X
Y
X
Y
1
1.37
1.6
1.9
1.65
1.57
1.46
1.38
1.34
1.26
1.14
1.12
1.12
0.92
0.78
0.55
0.57
0.56
0.55
0.72
0.67
0.63
0.57
0.73
0.81
0.92
2.39
2.28
2.11
2.00
1.93
1.82
1.66
1.63
1.63
1.41
1.24
0.93
1
1
1
Note 1) i = 2 for DB or DF, i = 1 for Single or DT.
Note 2) For Single or DT, use Pr=Fr when Fa/Frde.
Note 3) When the nominal contact angle is 15q, use linear interpolation to determine X, Y, and
e values of iFa/Cor that are not included in the table.
Note 4) For high-speed use (dmn value > 800,000), the centrifugal force of the roller must
also be taken into consideration in addition to the external load. Please consult NACHI
concerning such applications.
NACHI BEARING
Technical Description
2-3 Angular Contact Ball Bearing Load
In the case of angular contact ball bearings, the points where the
extended contact lines within the bearing and the axis as shown
in Figure 2.1 must be used as the bearing support points (load
centers).
Because of this, angular contact ball bearings are shown in
dimension tables with "a" dimensions indicating support point
positions. This consideration is particularly important when a
moment load is acting on a bearing series.
Axial component forces are generated when a radial load acts on an
angular contact ball bearing. You can calculate the axial component
forces using Formula 2.4.
Fa'
Bearing
Selection
Fr
Bearing
Life
(Formula 2.4)
Bearing
Tolerance
Fa’ : Induced axial load (N)
Fr : Radial load (N)
Y : Axial load factor
● Figure 2.1 Induced Axial Load for Angular Contact Ball Bearings
Due to these component forces, the axial load and dynamic equivalent
radial load acting on the bearing is as shown in Table 2.2.
Preload
and
Rigidity
● Table 2.2 Axial Load and Dynamic Equivalent Load of Angular Contact Ball Bearings
Bearing arrangement
II
Load conditions
Lubrication
Axial load
Dynamic equivalent radial load
I
Limiting
Speeds
Shaft and
Housing
Design
Fa
Bearing
Handling
FrI
FrII
I
II
Fa
FrI
FrII
II
I
Fa
FrI
FrII
I
II
Fa
FrI
Bearing
Arrangement
FrII
FrI, FrII : Radial load (N) applied to bearings I and II Fa
: External axial load (N)
: Axial load factors of bearings I and II
YI, YII
XI, XII : Radial load factors of bearings I and II
PrI, PrII : Dynamic equivalent radial load (N) of bearings I and II
Bearing Life
5
Technical Description
Bearing Life
2-4 Basic Static Load Rating and Static Equivalent Load
● Table 2.3 Static Load Factors
2.4.1 Basic Static Load Rating
Load applied to stationary bearings can create permanent indentions
in the load surfaces. While some level of deformation can be
tolerated, a level of deformation will be reached where noise and
vibration during operation of the bearing, will make the bearing
unusable. The term Basic Static Load Rating (Cor or Coa) refers to
the maximum contact stress value of the static load when the rolling
element and raceways contact.
Ball bearings — 4200 MPa
Roller bearings — 4000 MPa
With these contact stresses, the sum of deformations is
approximately 1/10,000 of the diameter of the rolling element.
(Figure 2.2).
Rolling element
Radial ball
bearings
Thrust ball
bearings
Single or DT
DB or DF
Nominal
contact angle
Xo
Yo
Xo
Yo
15°
25°
30°
40°
50°
55°
60°
0.5
0.5
0.5
0.5
2.74
3.28
3.98
0.46
0.38
0.33
0.26
1
1
1
1
1
1
1
2.74
3.28
3.98
0.92
0.76
0.66
0.52
1
1
1
2.4.3 Safety Factors
The basic static load rating is considered as the limiting load for
general applications.
An application may require a safety factor larger than 1.
Formula 2.8 and Table 2.4 show the calculation formula and safety
factors (guidelines).
Da
r
inne
r andceway
e
t
u
O ng ra
ri
Load
Raceway surface deformation G1
Rolling element surface deformation G2
(Formula 2.8)
Po max : Permissible static equivalent load (N)
Co
: Basic static load rating (N)
So
: Safety factors (Table 2.4)
● Table 2.4 Safety Factors So
● Figure 2.2 Permanent Indentation
Application conditions
2.4.2 Static Equivalent Load
Static equivalent load is the static load that reflects the actual load
conditions to the contact section of the rolling elements and raceway
receiving the maximum stress.
For radial bearings, radial load of a constant direction and magnitude
is called the static equivalent radial load, and for thrust bearings,
axial load of a constant direction and magnitude is called the static
equivalent axial load.
To calculate the static equivalent radial load, the larger of the two
values obtained from Formula 2.5 and Formula 2.6 are to be used.
(Formula 2.5)
(Formula 2.6)
High rotating accuracy is needed
Vibration and or impact present
Normal operating conditions
So
Ball bearings Roller bearings
2
3
1.5
2
1
1.5
2.4.4 Permissible Thrust Load
A permissible thrust load exists for bearings that can be applied with
axial load like an angular contact ball bearings.
For ball bearings, the permissible load is the smaller of the following
two values.
a Axial load when the contact pressure value between the roller
and raceway surfaces is 4200 MPa or less
b Axial load causing the contact ellipse formed between the roller
and raceway surface to deviate beyond the raceway shoulder
(Figure 2.3)
The static equivalent axial load is calculated using Formula 2.7.
(Formula 2.7)
Por
Poa
Fr
Fa
Xo
Yo
Axial load
: Static equivalent radial load (N)
: Static equivalent axial load (N)
: Radial load (N)
: Axial load (N)
: Static radial load factors (Table 2.3)
: Static axial load factors (Table 2.3)
Contact ellipse
Axial load
2b
2a
● Figure 2.3 Contact Ellipse
6
Bearing Life
NACHI BEARING
Bearing Tolerance
Technical Description
3
3-1 Radial Bearing Tolerances
The tolerance of rolling contact bearings includes dimensional and
running accuracy. The tolerances is classified by ISO 492 and JIS B
1514 (Rolling bearings - Tolerances), with precision rolling bearings
conforming to Class 5, 4, and 2.
Radial bearing tolerances are shown in Table 3.1 and Table 3.2 (page
8).
● Table 3.1 Tolerances of Inner Ring (JIS Class 5, Class 4, Class 2)
Nominal bearing
bore diameter
d (mm)
2.5
10
18
30
50
80
120
150
180
Incl.
10
18
30
50
80
120
150
180
250
Bore diameter deviation (1)
Single plane mean bore diameter variation (1)
'd mp
Class 5
Over
Unit: μm
Class 4
Single plane mean bore
Single plane bore difference (1)
diameter difference (1)
'd s
Class 2
Vd sp
Class 4
Class 2
Diameter series
High
0
0
0
0
0
0
0
0
0
Low
-5
-5
-6
-8
-9
-10
-13
-13
-15
High
0
0
0
0
0
0
0
0
0
Low
High
-4
-4
-5
-6
-7
-8
-10
-10
-12
0
0
0
0
0
0
0
0
0
Low
-2.5
-2.5
-2.5
-2.5
-4
-5
-7
-7
-8
Low
-4
-4
-5
-6
-7
-8
-10
-10
-12
High
0
0
0
0
0
0
0
0
0
Class 4
Class 5 Class 4 Class 2
Diameter series
0,2
High
0
0
0
0
0
0
0
0
0
Vd mp
Class 5
Low
-2.5
-2.5
-2.5
-2.5
-4
-5
-7
-7
-8
9
0,2
9
0,2
Max
Max
Max
Max
5
5
6
8
9
10
13
13
15
Max
4
4
5
6
7
8
10
10
12
Max
4
4
5
6
7
8
10
10
12
Max
3
3
4
5
5
6
8
8
9
3
3
3
4
5
5
7
7
8
2
2
2.5
3
3.5
4
5
5
6
1.5
1.5
1.5
1.5
2
2.5
3.5
3.5
4
Bearing
Selection
Bearing
Life
Bearing
Tolerance
Bearing
Arrangement
Preload
and
Rigidity
Lubrication
Unit: μm
Nominal bearing
bore diameter
d (mm)
Assembled bearing
Inner ring radial run-out Inner ring reference
inner ring reference face
of assembled bearing face runout with bore
runout with raceway (2)
K ia
Sd
Class 5 Class 4 Class 2 Class 5 Class 4 Class 2 Class 5 Class 4 Class 2
Over
2.5
10
18
30
50
80
120
150
180
Deviation of a single ring width
'B s
S ia
Class 5
Incl.
10
18
30
50
80
120
150
180
250
Max
Max
Max
Max
Max
Max
Max
Max
Max
4
4
4
5
5
6
8
8
10
2.5
2.5
3
4
4
5
6
6
8
1.5
1.5
2.5
2.5
2.5
2.5
2.5
5
5
7
7
8
8
8
9
10
10
11
3
3
4
4
5
5
6
6
7
1.5
1.5
1.5
1.5
1.5
2.5
2.5
4
5
7
7
8
8
8
9
10
10
13
3
3
4
4
5
5
7
7
8
1.5
1.5
2.5
2.5
2.5
2.5
2.5
5
5
Class 4/Class 2
Single bearing
High
0
0
0
0
0
0
0
0
0
Low
-40
-80
-120
-120
-150
-200
-250
-250
-300
High
0
0
0
0
0
0
0
0
0
VB s
Class 5/Class 4
Class 5 Class 4 Class 2
/Class 2
Duplex bearing (3)
Low
-40
-80
-120
-120
-150
-200
-250
-250
-300
Limiting
Speeds
Inner ring width
variation
High
0
0
0
0
0
0
0
0
0
Low
-250
-250
-250
-250
-250
-380
-380
-380
-500
Max
Max
Max
5
5
5
5
6
7
8
8
10
2.5
2.5
2.5
3
4
4
5
5
6
1.5
1.5
1.5
1.5
1.5
2.5
2.5
4
5
Note 1) Applies to bearings with cylindrical bore.
Note 2) Applies to ball bearings.
Note 3) Applies to the rings of single bearings made for mounted bearings.
Remark: The high deviation of bearing bore diameter of cylindrical bore bearings in Table 3.1 does not apply within a distance from the raceway ring face of 1.2 x r (max) of the chamfer.
Bearing Tolerance
7
Shaft and
Housing
Design
Bearing
Handling
Technical Description
Bearing Tolerance
● Table 3.2 Tolerances of Outer Ring (JIS Class 5, Class 4, Class 2)
Nominal bearing
outside diameter
D (mm)
Single plane mean outside diameter variation
of outer ring
Unit: μm
Outside diameter deviation
'D s
'D mp
Class 5
Class 4
Class 2
Class 4
Outside diameter variation in a single Mean outside diameter
radial plane (1)
variation
VD sp
Class 2
Class 5
Diameter series
Over
18
30
50
80
120
150
180
250
315
Incl.
30
50
80
120
150
180
250
315
400
High
0
0
0
0
0
0
0
0
0
Low
High
-6
-7
-9
-10
-11
-13
-15
-18
-20
0
0
0
0
0
0
0
0
0
Low
-5
-6
-7
-8
-9
-10
-11
-13
-15
High
0
0
0
0
0
0
0
0
0
Low
-4
-4
-4
-5
-5
-7
-8
-8
-10
Low
-5
-6
-7
-8
-9
-10
-11
-13
-15
High
0
0
0
0
0
0
0
0
0
Class 2 Class 5 Class 4 Class 2
Diameter series
0,2
High
0
0
0
0
0
0
0
0
0
VD mp
Class 4
Low
-4
-4
-4
-5
-5
-7
-8
-8
-10
9
0,2
9
0,2
0,2
Max
Max
Max
Max
6
7
9
10
11
13
15
18
20
Max
5
5
7
8
8
10
11
14
15
Max
5
6
7
8
9
10
11
13
15
Max
4
5
5
6
7
8
8
10
11
Max
4
4
4
5
5
7
8
8
10
3
4
5
5
6
7
8
9
10
2.5
3
3.5
4
5
5
6
7
8
2
2
2
2.5
2.5
3.5
4
4
5
Unit: μm
Nominal bearing
outside diameter
D (mm)
Over
18
30
50
80
120
150
180
250
315
Incl.
30
50
80
120
150
180
250
315
400
Outer ring radial runout of
assembled bearing
K ea
Class 5
Max
6
7
8
10
11
13
15
18
20
Class 4
Max
4
5
5
6
7
8
10
11
13
Class 2
Max
2.5
2.5
4
5
5
5
7
7
8
Variation of outside surface
generatrix inclination with
outer ring reference
Assembled bearing outer ring
reference face runout with
raceway (2)
SD
S ea
Class 5
Max
8
8
8
9
10
10
11
13
13
Class 4
Max
4
4
4
5
5
5
7
8
10
Class 2
Max
1.5
1.5
1.5
2.5
2.5
2.5
4
5
7
Class 5
Max
8
8
10
11
13
14
15
18
20
Class 4
Max
5
5
5
6
7
8
10
10
13
Class 2
Max
2.5
2.5
4
5
5
5
7
7
8
Deviation of a
single ring width
'C s
Corresponds to the
values of 'B s of
the inner ring being
matched with it.
Note 1) Applies to open type bearings.
Note 2) Applies to ball bearings.
Remark: The low outside diameter deviation of bearings in Table 3.2 does not apply within a distance from the ring face of 1.2 x r (max) of the chamfer.
8
Bearing Tolerance
Outer ring width variation
VC S
Class 5
Max
5
5
6
8
8
8
10
11
13
Class 4
Max
2.5
2.5
3
4
5
5
7
7
8
Class 2
Max
1.5
1.5
1.5
2.5
2.5
2.5
4
5
7
NACHI BEARING
Technical Description
3-2 Tolerances and Permissible Values of Angular Contact Ball Bearings for Thrust Loads (TAH/TBH Series)
Except for the outside diameter of outer ring outside diameter, accuracy of angular contact ball bearings for thrust loads conforms to JIS Class 4.
Outside diameter of outer ring tolerances is as shown in Table 3.3.
● Table 3.3 Tolerance of Outside Diameter
Nominal bearing
outside diameter
D (mm)
Unit: μm
Outside diameter deviation
'D s
Over
Incl.
High
Low
50
80
120
180
250
80
120
180
250
315
-30
-36
-43
-50
-56
-49
-58
-68
-79
-88
Bearing
Selection
Bearing
Life
Bearing
Tolerance
3-3 Tolerances of Cross Tapered Roller Bearings
Bearing
Arrangement
Tolerances for cross tapered roller bearings is shown in Table 3.4 and Table 3.5.
● Table 3.4 XRN Series Inner Ring and Outer Ring tolerances
Bearing no.
150XRN23
200XRN28
250XRN33
250XRN35
300XRN40
310XRN42
0330XRN045
350XRN47
375XRN49
400XRN55
0457XRN060
580XRN76
0685XRN091
950XRN117
Single plane mean bore
diameter variation
'd mp
Unit: μm
Single plane mean outside
diameter variation of outer ring
'D mp
Variation of assembled height Ts
Outer ring run-out (Max)
Lubrication
High
Low
High
Low
High
Low
0
0
0
0
0
0
+25
0
0
0
+25
+25
+38
0
-13
-15
-15
-10
-13
-13
0
-13
-13
-13
0
0
0
-75
0
0
0
0
0
0
+25
0
0
0
+25
+38
+38
0
-15
-18
-18
-13
-15
-15
0
-15
-15
-18
0
0
0
-75
+350
+350
+350
+350
+350
+350
+350
+350
+350
+350
+380
+406
+508
+750
-250
-250
-250
-250
-250
-250
-250
-250
-250
-250
-380
-406
-508
-750
Radial run-out Sideface runout
7
7
7
9
7
7
8
9
7
9
9
10
12
14
7
7
7
9
7
7
8
9
7
9
9
10
12
14
● Table 3.5 XRG (XRGV) Series Inner Ring and Outer Ring Tolerances
Bearing no.
130XRG23
140XRGV20
150XRG23
200XRGV028
320XRG43
480XRGV66
Single plane mean bore
diameter variation
'd mp
Preload
and
Rigidity
Limiting
Speeds
Shaft and
Housing
Design
Bearing
Handling
Unit: μm
Single plane mean outside
diameter variation of outer ring
'D mp
Variation of assembled height Ts
High
Low
High
Low
High
Low
0
0
0
0
0
0
-10
-13
-13
-15
-13
-45
0
0
0
0
0
-70
-15
-15
-15
-18
-15
-100
+350
+350
+350
+350
+350
+450
-250
-350
-250
-350
-250
-450
Inner ring run-out (Max)
Radial run-out Sideface runout
6
5
6
7
7
11
7
5
7
7
7
11
Bearing Tolerance
9
Technical Description
Bearing Tolerence
3-4 Ball Screw Support Bearing (TAB Series) Tolerances
Tolerances for ball screw support (TAB Series) is shown in Table 3.6 and Table 3.7.
● Table 3.6 Tolerances for Inner Ring (Including Outer Ring Width and Outer Ring Sideface Runout Reference to Raceway)
Nominal bearing
bore diameter
d (mm)
Single plane mean bore and
bore variation
'd mp, 'd s
Class 5
Class 4
Bore diameter
variation in a
single radial
plane
Mean bore
diameter
variation
Vd mp
Vd p
Deviation of a
single inner ring
width (or a single
outer ring width)
' B s, ' C s
Unit: μm
Side face runout with
Radial runout
Side face
reference to raceway
of assembled runout S d with of assembled bearing
bearing inner ring reference to inner ring S ia and of
K ia
assembled bearing
bore
outer ring S ea
Width
deviation of
Inner ring
VB s
Class 5 Class 4 Class 5 Class 4 Class 5/Class 4 Class 5 Class 4 Class 5 Class 4 Class 5 Class 4 Class 5 Class 4
Over
Incl.
High
Low
High
Low
Max
Max
Max
Max
High
Low
Max
Max
Max
Max
Max
Max
Max
Max
10
18
30
50
18
30
50
80
0
0
0
0
-5
-6
-8
-9
0
0
0
0
-4
-5
-6
-7
4
5
6
7
3
4
5
5
3
3
4
5
2
2.5
3
3.5
0
0
0
0
-80
-120
-120
-150
5
5
5
6
2.5
2.5
3
4
4
4
5
5
2.5
3
4
4
7
8
8
8
3
4
4
5
4
5
6
7
2
2.5
2.5
2.5
● Table 3.7 Tolerances for Outer Ring
Nominal bearing
outside diameter
D (mm)
Single plane mean outside diameter
variation of outer ring
'D mp, 'D s
Class 5
Over
30
50
80
Incl.
50
80
120
Unit: μm
High
0
0
0
Low
-7
-9
-10
Class 4
High
0
0
0
Low
-6
-7
-8
Variation of outside
Outside diameter
Radial runout of
Mean outside
Outside Inclination
surface generatrix
variation in a single
assembled bearing
diameter variation
of outer ring
inclination with
radial plane
outer ring
VD mp
SD
outer ring reference
VD p
K ea
VC s
Class 5
Class 4
Class 5
Class 4
Class 5
Class 4
Class 5
Class 4
Class 5
Class 4
Max
5
7
8
Max
5
5
6
Max
4
5
5
Max
3
3.5
4
Max
5
6
8
Max
2.5
3
4
Max
7
8
10
Max
5
5
6
Max
8
8
9
Max
4
4
5
For the TAB Series flush ground type, strict tolerances are established for outside diameter and bore diameter to minimize differences within
duplex bearings. (Table 3.8, Table 3.9)
● Table 3.8 Tolerances for Bore Diameter of Inner Ring (Class 4 Flush Ground)
Unit: μm
Nominal bearing
bore diameter
d (mm)
Over
10
18
30
50
Incl.
18
30
50
80
Single plane mean bore diameter variation
'd mp, 'd s
Class 4 flush ground
High
0
0
0
0
Tolerances for other than bore diameter conforms to Class 4 in Table 3.6.
10
Bearing Tolerance
Low
-4
-4
-4
-5
● Table 3.9 Tolerancs for Outside Diameter of Outer Ring (Class 4 Flush Ground)
Unit: μm
Nominal bearing Single plane mean outside diameter variation of outer ring
'D mp, 'D s
outside diameter
D (mm)
Class 4 flush ground
Over
30
50
80
Incl.
50
80
120
High
0
0
0
Low
-4
-5
-6
Tolerances for other than outside diameter conforms to Class 4 in Table 3.7.
NACHI BEARING
Technical Description
3-5 Tolerances for Ball Screw Support Bearing (TAF Series)
Tolerances for ball screw support (TAF Series) is shown in Table 3.10 and Table 3.11.
● Table 3.10 Tolerances for Inner Ring (Including Outer Ring Width, JIS Class 5)
Nominal bearing
bore diameter
d (mm)
Bore diameter
Mean bore
variation in a
diameter
single radial
variation
plane
Single plane mean bore
diameter variation
'd mp
Vd mp
Vd p
Unit: μm
Radial runout
Width
Outer and inner ring width
of assembled
deviation VBS
variation
bearing inner
of Inner Ring
ring
'B s, 'C s
VB s
K ia
Side face Side face runout with
runout with reference to raceway
reference to
of assembled
bore
bearing inner ring
Sd
S ia
Over
Incl.
High
Low
Max
Max
High
Low
Max
Max
Max
Max
18
30
50
80
30
50
80
120
0
0
0
0
-6
-8
-9
-10
5
6
7
8
3
4
5
5
0
0
0
0
-120
-120
-150
-200
5
5
6
7
4
5
5
6
8
8
8
9
8
8
8
9
● Table 3.11 Tolerances for Outer Ring (JIS Class 5)
Nominal bearing
outside diameter
D (mm)
Bearing
Selection
Bearing
Life
Unit: μm
Outside diameter
Variation of outside Assembled bearing
Radial runout
Mean outside Outer ring width
variation in a
surface generatrix outer ring reference
of assembled
variation
single radial diameter variation
inclination with outer ring face runout with
bearing outer ring
VD mp
VC s
plane
reference
raceway
Single plane mean outside
diameter variation of outer ring
'D mp
K ea
VD p
SD
S ea
Over
Incl.
High
Low
Max
Max
Max
Max
Max
Max
50
80
120
150
180
250
80
120
150
180
250
315
0
0
0
0
0
0
-9
-10
-11
-13
-15
-18
7
8
8
10
11
14
5
5
6
7
8
9
6
8
8
8
10
11
8
10
11
13
15
18
8
9
10
10
11
13
10
11
13
14
15
18
Lubrication
Limiting
Speeds
Shaft and
Housing
Design
Tolerances for tapered bores (Cylindrical roller bearings) is specified by JIS. Since JIS tolerances are rather broad, NACHI defines its own
narrower range for precision bearings.
● Table 3.12 Tolerances for Tapered Bores (Cylindrical Roller Bearings)
Nominal bearing
bore diameter
d (mm)
Over
18
30
50
80
120
180
250
315
Incl.
30
50
80
120
180
250
315
400
High
+10
+12
+15
+20
+25
+30
+35
+40
Bore diameter variation in a
single plane radial plane
'd 1mp- 'd mp
Class 4
Low
0
0
0
0
0
0
0
0
High
+6
+8
+9
+10
+13
+15
+18
+23
Bearing
Handling
Unit: μm
'd mp
Class 5
Class 5
Low
0
0
0
0
0
0
0
0
High
+5
+5
+6
+7
+10
+12
+15
+16
Vd p
Class 4
Low
0
0
0
0
0
0
0
0
High
+3
+4
+4
+5
+7
+9
+11
+12
Low
0
0
0
0
0
0
0
0
Class 5
Class 4
Max
3
4
5
5
7
8
9
12
Max
3
3
4
4
5
6
9
12
'd1mp'd1mp
I (d+'dmp)
Id1
ID
D
I (d1+'d1mp)
2
D
B
B
Theoretical tapered bore
Tapered bore with actual mean diameters at their deviations
D
d1
: Basic diameter at theoretical large end of tapered bore
'dmp
: Mean bore diameter deviation at theoretical small end of tapered bore
'd1mp
B
D
Bearing
Arrangement
Preload
and
Rigidity
3-6 Tolerances for Tapered Bores (Cylindrical Roller Bearings)
Mean bore diameter deviation at theoretical small end of a tapered bore
Bearing
Tolerance
: Nominal bearing bore diameter
: Mean bore diameter deviation at theoretical large end of tapered bore
: Nominal bearing inner ring width
: Nominal taper angle (half of cone angle)
● Figure 3.1 Tapered Bores of Cylindrical Roller Bearings
Bearing Tolerance
11
Technical Description
4
Bearing Arrangement
4-1 Duplex Bearing Features
In addition to a duplex set, precision angular contact ball bearings
and ball screw support bearings are available in 3-row duplex and
4-row duplex. Bearings in these combinations are manufactured
in sets with a desired preload and dimensional variation of outside
diameter and bore diameter within the bearing sets are controlled.
Because of this, avoid switching the duplex bearings in a set with
other bearings.
Table 4.1 shows the main combinations and describes their
characteristics.
● Table 4.1 Main Combinations and Characteristics
Main combinations
Cross section
Load capability Moment load rigidity
Speed
Features
● Radial loads and axial loads in both directions can be
applied.
● The load center distance is long, so moment load
capability is high.
● Misalignment or other mounting error increases internal
load and tends to generate premature flaking.
Back-to-back
(DB)
Load center distance
Face-to-face
(DF)
c
● The load center distance is decreased, so moment load
capability is low.
● Since moment load capability is low, increase in internal
load due to misalignment is kept under control. Because
of this, this combination is suitable when misalignment
can not be avoided or when shaft deflection is large
because of the load.
U
● Radial loads and axial loads can be applied in one
direction.
● Since the axial load capability is double that of a single
row, this combination is suitable for large axial load in
one-direction.
Load center distance
Tandem
(DT)
3-row duplex
(FFB)
U
Preload
4-row duplex
(FFBB)
12
Bearing Arrangement
● Radial loads and axial loads in both direction can be
applied.
● The axial load capability is double that of a single-row,
but preload is not distributed uniformly to each bearing,
and the single-row configuration is double that of the
two-row configuration.
This non-uniform preload distribution makes appropriate
preload settings difficult at high speed rotation.
● Radial loads and axial loads in both directions can be
applied.
● Compared to the back-to-back configuration under the
same preload clearance, preload is doubled and rigidity
is greater.
NACHI BEARING
Technical Description
4-2 Mounting and Mounting Symbols
The symbols used for each type of combination are shown in
Table 4.1. The arrangement sequence and direction of the load are
important for duplex bearings. Because of this, the outside surface of
the outer ring of the duplex bearings in Figure 4.1 has a combination
mark ([<]) that can be used to check the arrangement sequence. If
the bearings are arranged in the correct sequence, the marks on the
outside surface of each bearing appear as a "<"
Bearing
Selection
DB
DF
DT
FFB
BFF
FFF
Bearing
Life
Bearing
Tolerance
Bearing
Arrangement
FFBB
BBFF
FFFB
BFFF
Preload
and
Rigidity
● Figure 4.1 Set Combinations and Outer Ring Combination Marks
Lubrication
4-3 Flush Ground Angular Contact Ball Bearings
For flush ground angular contact ball bearings, the face side width
dimension (Af) and back side width dimension (Ab) are controlled
to be the same. Therefore, desired preload is obtained in any set of
combination. (Figure 4.2).
Flush ground angular contact ball bearings are delivered singularly
(suffix symbol; U) or in a duplex set (suffix symbol: DU). Duplex
sets have a small dimensional variation in bore diameter and outer
diameter. When using U series in a combination, select a bearing
whose actual measured outside diameter and bore diameter values
are close to each other.
For the ball screw support bearing TAB Series flush ground type, a
combination ([<]) mark is put on the outside surface of the outer
ring. For information about set combinations and the combination
marks, see Figure 4.3.
Af
Limiting
Speeds
Shaft and
Housing
Design
DB
DF
FFB
BFF
Bearing
Handling
DT
FFF
FFBB
BBFF
FFFB
BFFF
● Figure 4.3 Flush Ground Bearing Set Combinations and Combination Marks
Ab
Af = Ab
● Figure 4.2 Flush Ground Angular Contact Ball Bearing
Bearing Arrangement
13
Technical Description
5
Preload and Rigidity
5-1 Preload Objectives
Rolling contact bearings generally have internal clearance suitable
for operating conditions, angular contact ball bearings also may be
installed with appropriate predetermined negative clearance (axial
preload).
This is known as "preload". Care is required when determining
preloads. An improper preload can increase friction torque, raise
temperature, cause abnormal sounds, shorten bearing life, and
cause other problems.
The following is a list of what can be achieved by preloading.
● Reduced axial displacement due to external force and greater
axial rigidity
● Prevention of vibration and noise and increased speed due to
greater axial rigidity
● Less chance of fretting due to external vibration
● Smooth rolling rotation
● Lower noise and less heat due to ball centrifugal force and
gyro-moment
of the two different axes. This is called a "gyro-moment" (Figure 5.1).
The size of the gyro-moment is proportional to rotational angular
velocity and orbital angular velocity. Gyro-moment is small enough to
be ignored at low-speed rotation, but heat generation due to slipping
caused by gyro-motion in the high-speed rotation range cannot be
ignored. In order to suppress slipping caused by gyro-motion, friction
(ball load x coefficient of friction ) between the balls and raceway
surface must be maintained. This means that there are times when
minimal preload can be chosen.
Ball rotation
Gyro-moment
Gyro-moment
The balls of an angular contact ball bearing spin around rotational
axes while they revolve around an orbital axis (axis line). An angle
is performed between the rotational axis and orbital axis, and a
moment is generated when a ball attempts to revolve on the center
● Figure 5.1 Gyro-moment
5-2 Preload Methods
1.2
Life ratio
(Life=1 when radial clearance=0)
Preloading combination bearings is broadly divided between fixedposition preload and fixed-pressure preload.
Table 5.1 (page 15) shows graphic examples and describes the
characteristics of each type of preloading.
A cylindrical roller bearing with tapered bore also may be used with
radial preload (negative radial clearance) applied. However, caution
is required because radial preload that is too large dramatically
reduces service life (Figure 5.2).
Radial Load: 4710N
(3% of dynamic load rating)
1.0
0.8
0.6
0.4
0.2
0
-0.020
0
0.020
0.040
0.060
Radial clearance (mm)
● Figure 5.2 Cylindrical Roller Bearing (NN3020) Radial Clearance and
Service Life
5-3 Measuring Preload
a Axial load measurement method
For spring preloading (fixed-pressure preload), the preload is
known if the spring displacement is known.
For nut preloading (fixed-position preload), the preload can be
determined based on the relationship between nut tightening
torque and tightening force. However, that caution is required
because there is wide variation in the relationship between
nut tightening torque and tightening force due to accuracy and
roughness of the threaded portion.
b Axial displacement measurement method
The preload can be determined based on the relationship
between the axial load on the bearing and axial displacement.
14
Preload and Rigidity
c Bearing starting friction torque measurement method
To perform this measurement, your first need to create a graph of
the load and starting torque of the bearing itself. However, caution
is required because of variation due to bearing type, lubrication
conditions, etc.
NACHI BEARING
Technical Description
● Table 5.1 Preload Methods
Preload
methods
Design example
Features
● Since bearing spread is used, the prescribed preload can be obtained simply by
tightening a nut.
● Fit causes preload inconsistency.
● Heat generation causes preload inconsistency.
● Applying an axial load that is too great can cause loss of preload.
Fixedposition
preload
Method using either a duplex bearing with pre-adjusted preload or a
dimension adjusted spacer
Bearing
Selection
Bearing
Life
● Uniform preload, even if fit is inconsistent
● Further tightening possible
● Heat generation causes preload inconsistency.
● Applying an axial load that is too great can cause loss of preload.
Bearing
Tolerance
Bearing
Arrangement
Preload adjustment method using nut tightening
Preload
and
Rigidity
● Constant uniform preload while running
● No loss of preload
● Suitable for high speeds
● In principle, one-direction axial load can be applied
● Inferior rigidity compared to fixed-position preload of the same preload
Fixedpressure
preload
Lubrication
Limiting
Speeds
Method using spring
Shaft and
Housing
Design
5-4 Preload Effect
e Axial displacement is given as bearing B displacement Gw.
(Bearing B displacement is the displacement for Tp subtracted
from the displacement for Tb.)
The reason for this is that the displacements of two preloaded
bearings are not uniform within the range that the preload does not
become zero due to outside load. (Figure 5.3 is uniform). In other
words, bearing A is displaced only as much as bearing B is displaced
by the external load.
After external load becomes great and preload is eliminated, bearing
B load Tb becomes the same as external load Tw, and bearing A
load is eliminated. The size of the external load when this preload is
eliminated is indicated in Figure 5.3 as Tpo.
Bearing A
Bearing B
Tw
Axial elastic displacement amount Ga
Graphic analysis of load distribution and axial displacement on two
bearings when preload is applied with an external load, as shown in
Figure 5.3, is performed as described below.
a Graph the Axial Load T - Axial Deflection Ga curve for bearing A.
b Locating preload Tp on the T-axis, determine the point of
intersection for bearing A curve, and then graph the T - Ga
curve for Bearing B point P.
c Link the above two curves horizontally along the T-axis for a
length that corresponds to the external load value Tw.
d Loads Ta and Tb, which correspond to the points of intersection
of the lines, are the loads of each bearing under external load
conditions.
O'
ring
f bea
T-Ga
eo
curv
A
P
T-Ga
c
urve
Applied load Tw
O
Ta
Tp
Tb
of be
aring
B
Tpo
Axial load
● Figure 5.3 Fixed-position Preload
Preload and Rigidity
15
Bearing
Handling
Technical Description
Preload and Rigidity
5-5 Standard Preload and Axial Rigidity
5.5.1 Angular Contact Ball Bearing
● Table 5.2 Preload Factors for Multiple-row Arrangements
Preloads and axial rigidity for face-to-face and back-to-back duplex
mounting are shown in Table 5.3 1 to 6 (pages 16 through
18). Preloads for multiple-row arrangements can be obtained by
multiplying by the coefficients in Table 5.2.
3-row arrangement
4-row arrangement
FFB·BFF
FFFB·BFFF
FFBB·BBFF
1.36
1.57
2
● Table 5.3
1 7900C Series with 15° Contact Angle
E (extra-light preload)
Bore diameter number
00
01
02
03
04
05
06
07
08
09
10
Preload
(N)
5
7
8
8
15
15
15
25
25
35
35
Axial rigidity
(N/μm)
10
12
13
13
19
19
21
28
28
35
35
L (light preload)
Preload
(N)
15
20
25
25
40
50
50
70
80
100
100
Axial rigidity
(N/μm)
15
18
21
21
27
33
36
41
44
53
56
M (medium preload)
Preload
(N)
30
40
50
50
80
100
100
140
155
195
195
Axial rigidity
(N/μm)
20
24
28
28
36
43
48
56
60
70
72
2 7900AC Series with 25° Contact Angle
L (light preload)
Bore diameter number
00
01
02
03
04
05
06
07
08
09
10
16
Preload and Rigidity
Preload
(N)
20
20
29
29
59
69
78
88
88
98
118
Axial rigidity
(N/μm)
33
33
42
42
65
69
78
88
98
109
118
M (medium preload)
Preload
(N)
88
98
108
118
235
265
294
323
412
470
520
Axial rigidity
(N/μm)
59
65
67
74
107
120
134
147
165
188
208
H (heavy preload)
Preload
(N)
196
216
235
255
490
560
628
785
1,000
1,040
1,140
Axial rigidity
(N/μm)
82
90
94
102
149
169
190
212
244
260
284
NACHI BEARING
Technical Description
3 7000C Series with 15° Contact Angle
E (extra-light preload)
Bore diameter number
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
Preload
(N)
20
20
20
20
50
50
50
70
70
70
70
100
100
100
145
145
145
195
195
195
195
L (light preload)
Axial rigidity
(N/μm)
13
14
15
16
23
26
27
33
34
34
36
43
43
47
57
57
57
65
65
68
70
Preload
(N)
50
50
50
50
100
100
100
145
145
145
145
195
195
195
295
295
295
390
390
390
390
Axial rigidity
(N/μm)
20
21
23
25
33
36
38
46
49
49
51
56
58
61
75
77
75
89
87
91
93
M (medium preload)
Preload
(N)
100
100
100
100
195
195
195
295
295
295
295
390
390
390
590
590
590
785
785
785
785
H (heavy preload)
Axial rigidity
(N/μm)
29
31
34
35
48
50
53
64
68
68
70
78
82
85
105
107
105
125
121
125
127
Preload
(N)
145
145
145
145
295
295
390
390
590
590
590
785
785
785
1170
1170
1170
1470
1470
1470
1470
Axial rigidity
(N/μm)
37
39
42
43
59
63
75
75
98
98
100
112
115
123
149
153
149
171
165
171
173
4 7000AC Series with 25° Contact Angle
L (light preload)
Bore diameter number
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
Preload
(N)
39
39
49
59
59
108
118
127
147
216
225
314
333
363
392
412
529
549
676
706
745
Axial rigidity
(N/μm)
39
44
49
59
59
83
91
98
113
135
141
157
167
191
196
206
230
239
260
272
287
M (medium preload)
Preload
(N)
118
127
157
216
274
392
441
539
617
745
784
1,040
1,098
1,225
1,460
1,530
1,900
1,990
2,185
2,300
2,400
Axial rigidity
(N/μm)
62
67
83
98
110
140
158
174
193
213
224
254
268
299
332
348
373
390
405
427
445
Axial rigidity
(N/μm)
95
104
118
144
152
187
208
236
256
300
317
341
362
402
443
464
504
530
555
580
608
Preload and Rigidity
Bearing
Life
Bearing
Tolerance
Bearing
Arrangement
Preload
and
Rigidity
Lubrication
Limiting
Speeds
Shaft and
Housing
Design
H (heavy preload)
Preload
(N)
314
343
353
520
608
804
892
1,156
1,176
1,646
1,744
2,078
2,205
2,450
3,010
3,155
3,880
4,080
4,600
4,810
5,050
Bearing
Selection
Bearing
Handling
17
Technical Description
Preload and Rigidity
5 7200C Series with 15° Contact Angle
E (extra-light preload)
Bore diameter number
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
Preload
(N)
30
30
30
30
70
70
70
100
100
100
100
145
145
145
195
195
195
295
295
295
295
L (light preload)
Axial rigidity
(N/μm)
16
16
17
17
25
29
29
35
36
36
39
46
46
47
54
56
58
68
67
68
68
Preload
(N)
70
70
70
70
145
145
145
195
195
195
195
295
295
295
390
390
390
490
490
490
490
Axial rigidity
(N/μm)
24
24
25
25
37
41
41
47
49
50
52
63
61
64
73
75
77
85
83
85
85
M (medium preload)
Preload
(N)
145
145
145
145
295
295
295
490
490
490
490
590
590
590
785
785
785
980
980
980
980
H (heavy preload)
Axial rigidity
(N/μm)
36
36
38
37
53
58
58
74
77
77
80
88
84
88
102
105
105
117
114
114
115
Preload
(N)
195
195
195
195
490
490
590
590
785
785
785
980
980
980
1470
1470
1470
1960
1960
1960
1960
Axial rigidity
(N/μm)
42
42
44
44
71
77
83
82
98
98
102
114
109
113
139
144
143
166
161
159
159
6 7200AC Series with 25° Contact Angle
L (light preload)
Bore diameter number
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
18
Preload and Rigidity
Preload
(N)
39
39
69
78
118
147
157
225
255
333
353
460
540
600
610
650
800
940
1,200
1,235
1,588
Axial rigidity
(N/μm)
44
44
57
60
74
92
92
119
127
145
153
177
186
206
210
223
241
262
285
294
324
M (medium preload)
Preload
(N)
186
196
265
274
420
430
628
853
950
1,200
1,295
1,500
1,600
2,069
2,108
2,255
2,725
2,970
3,745
3,870
4,930
Axial rigidity
(N/μm)
78
78
95
98
120
139
165
194
216
241
259
278
280
328
335
358
389
407
441
450
503
H (heavy preload)
Preload
(N)
412
421
530
628
853
922
1,314
1,890
1,960
2,470
2,655
3,145
3,410
4,175
4,260
4,310
5,730
6,090
7,620
8,140
9,950
Axial rigidity
(N/μm)
108
111
129
143
164
188
227
270
288
321
345
379
383
440
444
464
531
549
591
612
677
NACHI BEARING
Technical Description
5.5.2 High-speed Angular Contact Ball Bearings
5.5.3 Thrust Load Angular Contact Ball Bearings
● Table 5.4 BNH000 Series with 15° Contact Angle
● Table 5.5
1 TAH Series with 30° Contact Angle
Bore diameter Bore diameter
number
(mm)
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
24
26
28
30
32
34
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
120
130
140
150
160
170
L (standard preload)
Preload
(N)
78.5
98.1
98.1
98.1
147
147
147
245
245
294
294
392
392
392
490
588
588
785
834
1080
1180
1370
Axial rigidity
(N/μm)
44
49
52
54
61
64
67
88
91
98
98
115
119
123
136
144
147
163
174
200
206
221
Nominal bore
diameter
(mm)
50
55
60
65
70
75
80
85
90
95
100
105
110
120
130
140
150
160
170
M (medium preload)
Preload
(N)
294
392
392
392
588
588
686
686
1080
1080
1080
1180
1370
1470
1860
1960
2450
2650
3040
Axial rigidity
(N/μm)
226
262
280
280
327
327
361
361
449
449
469
490
528
566
621
654
721
779
800
Bearing
Selection
Bearing
Life
Bearing
Tolerance
Bearing
Arrangement
Preload
and
Rigidity
Lubrication
Limiting
Speeds
Shaft and
Housing
Design
2 TBH Series with 40° Contact Angle
Nominal bore
diameter
(mm)
50
55
60
65
70
75
80
85
90
95
100
105
110
120
130
140
150
160
170
M (medium preload)
Preload
(N)
539
686
686
686
1080
1080
1270
1270
1860
1860
1860
2060
2450
2550
3330
3530
4310
4510
5300
Bearing
Handling
Axial rigidity
(N/μm)
415
458
490
528
599
599
671
671
776
810
847
858
943
1,020
1,111
1,177
1,269
1,367
1,431
Preload and Rigidity
19
Technical Description
Preload and Rigidity
5.5.4 Ball Screw Support Bearings
● Table 5.6
1 TAB Series with 60° Contact Angle Standard Preload: M (Medium)
Bearing no.
15TAB04
17TAB04
20TAB04
25TAB06
30TAB06
35TAB07
40TAB07
40TAB09
45TAB07
45TAB10
50TAB10
55TAB10
55TAB12
60TAB12
2-row arrangement
3-row arrangement
DB/DF
BFF/FFB
Preload
(N)
2160
2160
2160
3330
3330
3920
3920
5200
4120
5980
6280
6280
7060
7060
Axial rigidity Starting torque
(N/μm)
(N·cm)
735
15
735
15
735
15
981
20
981
20
1230
25
1230
25
1320
50
1270
30
1470
60
1520
65
1520
65
1770
70
1770
70
Preload
(N)
2940
2940
2940
4510
4510
5300
5300
7060
5590
8140
8530
8530
9610
9610
4-row arrangement
BBFF/FFBB
Axial rigidity Starting torque
(N/μm)
(N·cm)
1080
20
1080
20
1080
20
1470
27
1470
27
1770
35
1770
35
1910
68
1910
40
2160
82
2260
88
2260
88
2550
95
2550
95
Preload
(N)
4310
4310
4310
6670
6670
7840
7840
10400
8240
12000
12600
12600
14100
14100
BFFF/FFFB
Axial rigidity Starting torque
(N/μm)
(N·cm)
1470
30
1470
30
1470
30
1960
40
1960
40
2350
50
2350
50
2550
100
2550
60
2890
120
3040
130
3040
130
3480
140
3480
140
Preload
(N)
3430
3430
3430
5200
5200
6180
6180
8140
6470
9410
9810
9810
11100
11100
Axial rigidity Starting torque
(N/μm)
(N·cm)
1320
25
1320
25
1320
25
1910
30
1910
30
2300
40
2300
40
2500
80
2500
45
2790
95
2940
100
2940
100
3380
110
3380
110
Note) Starting torque shows values for an open type and non-contact seal type with grease lubrication.
2 TAF Series with 50° or 55° Contact Angle Standard Preload: M (Medium)
Bearing no.
25TAF06
30TAF07
35TAF09
40TAF09
40TAF11
45TAF11
50TAF11
60TAF13
60TAF17
80TAF17
100TAF21
120TAF03
2-row arrangement
3-row arrangement
DB/DF
BFF/FFB
Preload
(N)
1670
1860
3700
3700
4600
4600
4600
5200
8300
8300
13200
19600
Axial rigidity Starting torque
(N/μm)
(N·cm)
555
642
908
908
1020
1020
1020
1130
1440
1440
1970
2550
20
20
55
55
80
80
80
105
215
215
485
700
Note) Starting torque shows values with grease lubrication.
20
Preload and Rigidity
Preload
(N)
2270
2530
5030
5030
6250
6250
6250
7070
11300
11300
17900
26600
4-row arrangement
BBFF/FFBB
Axial rigidity Starting torque
(N/μm)
(N·cm)
805
944
1340
1340
1530
1530
1530
1680
2110
2110
2940
3810
27
27
75
75
110
110
110
145
290
290
660
950
Preload
(N)
3340
3720
7400
7400
9200
9200
9200
10400
16600
16600
26400
39200
BFFF/FFFB
Axial rigidity Starting torque
(N/μm)
(N·cm)
1110
1284
1816
1816
2040
2040
2040
2260
2880
2880
3940
5100
40
40
110
110
160
160
160
210
430
430
970
1400
Preload
(N)
2620
2920
5810
5810
7220
7220
7220
8160
13000
13000
20700
30800
Axial rigidity Starting torque
(N/μm)
(N·cm)
1060
1180
1680
1680
1960
1960
1960
2140
2660
2660
4160
4810
30
30
85
85
125
125
125
165
340
340
760
1100
NACHI BEARING
The radial internal clearance for multiple-row cylindrical roller
bearings is specified by JIS, NACHI defines its own narrower range
● Table 5.7
1 Cylindrical Bore Bearing Non-interchangeable Clearance
Nominal bearing bore
diameter
d (mm)
Over
24
30
40
50
65
80
100
120
140
160
180
200
225
250
280
315
Incl.
30
40
50
65
80
100
120
140
160
180
200
225
250
280
315
355
Unit: μm
Cylindrical bore bearing clearance (non-interchangeable)
C1na
Min
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
C2na
Max
10
12
15
15
20
25
25
30
35
35
40
45
50
55
60
65
Min
10
12
15
15
20
25
25
30
35
35
40
45
50
55
60
65
Cna
Max
25
25
30
35
40
45
50
60
65
75
80
90
100
110
120
135
Min
25
25
30
35
40
45
50
60
65
75
80
90
100
110
120
135
C3na
Max
35
40
45
50
60
70
80
90
100
110
120
135
150
165
180
200
Min
40
45
50
55
70
80
95
105
115
125
140
155
170
185
205
225
Nominal bearing bore
diameter
d (mm)
Incl.
30
40
50
65
80
100
120
140
160
180
200
225
250
280
315
355
Bearing
Selection
Max
50
55
65
75
90
105
120
135
150
165
180
200
215
240
265
295
2 Tapered Bore Bearing Non-interchangeable Clearance
Over
24
30
40
50
65
80
100
120
140
160
180
200
225
250
280
315
Technical Description
in order to maximize rotation accuracy. The radial internal clearances
for cylindrical bore bearings and tapered bore bearings are shown
in Table 5.7. Caution is required when handling and installing
bearings with non-interchangeable clearances, because there is no
interchangeability with another bearing's outer ring or inner ring.
5.5.5 Radial Internal Clearance for Multiple-row
Cylindrical Roller Bearings
Bearing
Life
Bearing
Tolerance
Bearing
Arrangement
Preload
and
Rigidity
Lubrication
Limiting
Speeds
Shaft and
Housing
Design
Unit: μm
Tapered bore bearing clearance (non-interchangeable)
C9na
Min
5
5
5
5
10
10
10
15
15
15
20
20
25
25
30
30
C1na
Max
10
12
15
15
20
25
25
30
35
35
40
45
50
55
60
65
Min
15
15
17
20
25
35
40
45
50
55
60
60
65
75
80
90
C2na
Max
25
25
30
35
40
55
60
70
75
85
90
95
100
110
120
135
Min
25
25
30
35
40
45
50
60
65
75
80
90
100
110
120
135
Max
35
40
45
50
60
70
80
90
100
110
120
135
150
165
180
200
Preload and Rigidity
21
Bearing
Handling
Technical Description
6
Lubrication
6-1 Purpose of Lubrication
The main purposes of rolling bearing lubrication is to reduce bearing
friction and wear, and to prevent seizure. The appropriate lubrication
methods and lubricating agents greatly influences rolling contact
bearing performance and service life.
The following are the purposes of lubrication.
a Lubrication of friction surfaces
1) Reduce rolling friction on roller and raceway surfaces, and reduce
sliding friction on roller and guide surfaces in roller bearings
2) Reduce sliding friction between the roller and the cage
3) Reduce sliding friction on cage and raceway ring guide surfaces
b Removal of friction-generated heat and heat transmitted from
other mechanisms
c Dust-proofing and rust prevention
d Reduce stress concentration
1) Uniform distribution of stress on points or linear-contact rolling
surfaces.
2) Buffering of impact load
6-2 Lubrication Methods
6.2.1 Oil Lubrication
a Forced lubrication (jet lubrication)
● Forced lubrication is used when cooling is required at relatively
high speed rotation or under high ambient temperatures.
● Jet lubrication supplies vaporized lubricating oil using
pressurized oil and a small nozzle, which has a cooling effect.
● The oil drain port must be larger than the oil supply port
because agitation of oil that collects inside the housing
increases heat generation and power loss. Particularly with jet
lubrication, an oil drain port that is at least 10 times larger than
the supply port opposite the nozzle is needed, and a pump
should be used for forced draining.
● Figure 6.1 shows an example of jet lubrication.
heating effect, this type of lubrication is suitable for relatively
low load applications.
c Oil air lubrication
● With oil air lubrication, a small amount of lubricating oil is
discharged by a measurement piston at fixed intervals, the
lubricating oil is supplied by the mixing valve into compressed
Air
Air filter
Pressure adjustment value
Mist generator
Air escapes here.
● Figure 6.2 Example of Spindle Unit Using Vapor Lubrication
Oil inlet
Generally, the nozzle is directed between
the cage and the inner ring.
Pressure: 10 to 50N/cm2
Nozzle orifice size: 1 to 2 mm
Oil capacity: 500 cc/min. (minimum)
● Figure 6.1 Jet Lubrication Example
b Vapor lubrication (oil mist lubrication)
● With this lubrication method, the bearing is air cooled and a
small amount of oils required for lubrication is vaporized and
sprayed onto the bearing. Figure 6.2 shows an example of oil
mist lubrication.
● Air sent to the mist generator via the pressure adjustor valve is
mixed with oil, which is sprayed on the bearing.
● The nozzle can spray directly onto the bearing, or it can spray
onto the bearing using the centrifugal force of the tapered part
of a slinger installed on the axis (Figure 6.3).
● Generally, the mist pressure is 5 to 15 N/cm2, with a few cc's
of oil mixed with 10 to 50ℓ/parts of air every hour.
● Oil mist uses only a small amount of oil so it is suitable for
high-speed operation with little bearing power loss, but since
the specific heat of air is not large and it does not have great
22
Lubrication
● Figure 6.3 Example of Mist Oil Delivery by Slinger
NACHI BEARING
Technical Description
air, and then supplied continually to rolling part of the bearing.
● Since a small and measured amount of new lubricating oil is
constantly being supplied, this method is suitable for highspeed applications where little heat is generated.
● Oil air lubrication is more environmentally friendly because oil
requirements are 1/10 that of vapor lubrication and the oil is
delivered in the form of droplets rather than a mist.
● Figure 6.4 shows an example of oil air lubrication.
6.2.2 Grease Lubrication
Note the following precautions whenever using grease lubrication.
● Select the proper grease. For examples of the main types of
grease used for machine tool bearings, see Table 6.1.
● Make sure the grease replenishment amount and locations are
correct. A greasing amount of 10 to 20% of the bearing internal
space volume is recommended for high-speed roller bearings.
Note, however, that 40 to 50% is recommended for a ball screw
support bearing (open type).
● Over-greasing can result in very high temperatures and large
power loss due to agitation. For information about internal
space volume of bearings, see Table 6.2 (page 24 to 25).
● For an example illustrating the difference in bearing temperature
increase due to lubrication method, see Figure 6.5.
Oil inlet port 4 locations (1 location/1 bearing)
Bearing
Selection
Bearing
Life
Bearing
Tolerance
60
Outer ring temperature increase (°C)
Grease lubrication (ISOFLEX NBU 15, 15% greasing)
50
Jet lubrication (ISO VG2 compliant, 1000 cc/min)
Preload
and
Rigidity
40
30
Lubrication
20
Limiting
Speeds
10
0
0
Oil/air discharge ports x 2 places
● Figure 6.4 Example of Spindle Unit Using Oil Air Lubrication
Bearing
Arrangement
Oil air lubrication (ISO VG46 compliant, 0.02 cc/30 min.)
5
10
Speed (×1000 rpm)
15
20
● Figure 6.5 Comparison of Temperature Increase Caused by Different
Lubrication Methods
● Table 6.1 Main Grease Used for Machine Tool Bearings
Grease brand
Manufacturer
Base oil
Thickener
Recommended
operation
temperature range
°C
Main applications
ISOFLEX NBU15
NOK KLUBER
Ester Oil
Barium composite
-40 ~ +130
Spindle bearing
ISOFLEX LDS18 Special A
NOK KLUBER
Ester Oil
Lithium
-60 ~ +130
Spindle bearing
Multemp LRL No. 3
Kyodo Yushi
Polyol Ester Oil
Lithium
-50 ~ +150
Spindle bearing
Alvania Grease S No. 2
Showa Shell Oil
Mineral Oil
Lithium
-25 ~ +120
Ball Screw Support Bearings
Multemp PS No. 2
Kyodo Yushi
Diester Oil + Hydrocarbon Oil
Lithium
-55 ~ +130
Ball Screw Support Bearings
Lubrication
23
Shaft and
Housing
Design
Bearing
Handling
Technical Description
Lubrication
● Table 6.2 Bearing Internal Space Volume
1 Internal space volume of angular contact ball bearings and cylindrical roller bearings
Bore diameter Bore diameter
number
(mm)
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
24
26
28
30
32
34
36
38
40
24
Lubrication
10
12
15
17
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
120
130
140
150
160
170
180
190
200
Unit: cc/each
Series
7900C
7900AC
0.44
0.49
0.68
0.68
1.5
1.9
2.2
3.0
5.2
5.7
6.2
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
7000C
7000AC
0.9
1.0
1.4
1.7
2.9
3.4
4.8
6.4
7.8
10.2
10.7
15.9
17.0
18.2
27.7
28.7
32.1
36.3
49.2
53.0
55.1
−
−
−
−
−
−
−
−
−
−
−
7200C
7200AC
1.2
1.7
2.2
3.0
4.7
5.3
8.2
10.3
13.0
15.4
18.6
25.9
33.2
39.1
45.2
49.4
59.0
73.5
93.1
117
135
−
−
−
−
−
−
−
−
−
−
−
BNH000
−
−
−
−
−
−
−
5.6
7.2
9.0
9.7
14.0
15.0
16.0
22.0
23.0
30.0
31.0
40.0
42.0
43.0
54.0
66.0
71.0
108
114
138
174
227
−
−
−
TAH
TBH
−
−
−
−
−
−
−
−
−
−
8.0
12.0
13.0
14.0
19.0
20.0
27.0
28.0
38.0
40.0
41.0
52.0
65.0
70.0
105
111
139
167
225
−
−
−
NN3000
NNU4900
−
−
−
−
−
3.6
5.9
7.5
9.5
12.8
13.8
19.6
20.7
21.8
30.4
32.9
46.3
47.8
62.9
64.5
67.3
91.8
114
126
178
195
235
288
374
508
530
684
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
49.5
57.9
59.6
86.4
102
114
195
199
209
281
296
448
NACHI BEARING
Technical Description
2 Ball Screw Support Bearing (TAB Series) Internal Space Volume
Bearing no.
15TAB04
17TAB04
20TAB04
25TAB06
30TAB06
35TAB07
40TAB07
40TAB09
45TAB07
45TAB10
50TAB10
55TAB10
55TAB12
60TAB12
Internal space volume
[cc/each]
3.8
3.8
3.8
4.8
4.8
5.8
5.8
14
6.5
15
16
16
19
19
3 Ball Screw Support Bearing (TAF Series) Internal Space Volume
Bearing no.
25TAF06
30TAF07
35TAF09
40TAF09
40TAF11
45TAF11
50TAF11
60TAF13
60TAF17
80TAF17
100TAF21
120TAF03
Internal space volume
[cc/each]
9.3
14
26
26
45
45
45
71
150
150
282
473
6.2.3 Grease Life
Grease life is affected by operating temperature, grease type, rotation
speed, load, and other factors. Grease life approximate estimates for
a rolling contact bearing, which is used as a representative example,
can be calculated using Formula 5.1.
(Formula 5.1)
Bearing
Selection
L : Grease life (hours)
T : Bearing temperature (°C)
SG : Life reduction factor based on grease type
Grease type
Long life petroleum grease
and silicon grease
Bearing
Life
SG
Bearing
Tolerance
0
Conventional petroleum grease
1.0
Diester and
and low temperature grease
2.9
Bearing
Arrangement
Preload
and
Rigidity
Lubrication
SN
d
n
(dn)L
Limiting
Speeds
: Life reduction factor based on rotation speed
: Nominal bearing bore diameter (mm)
: Bearing speed (rpm)
: Bearing type-specific speed factor
Bearing type
Shaft and
Housing
Design
Bearing
Handling
(dn)L
Angular contact ball bearings
400,000
Cylindrical roller bearings
200,000
SW : Load-specific life reduction factor
C : Basic dynamic load rating (N)
w : Bearing load (N)
Lubrication
25
Technical Description
7
Limiting Speeds
7-1 Limiting Speed Correction
Using a bearing at high speeds that exceed its limit generates
frictional heat inside the bearing, which can cause temperatures to
rise to levels that will not support bearing performance. The limit on
the empirical rotation speed that avoids these problems is called the
"rotation speed limit".
The rotation speed limit depends on the bearing type, dimensions,
lubricating method, load, etc. The rotation speed limit of a contact
seal bearing is limited by the circumferential speed of the contact
sections of the seal and raceway ring. The dimension tables in this
catalog show rotation speed limits for grease lubrication and oil
lubrication, but these values all assume light load, horizontal shaft
operation, and proper lubrication.
Though normally two or more pre-loaded angular contact ball bearings
are used, the rotation speed is limited in so it is necessary to multiply the
speeds in the dimension tables by the correction factors shown in Table
7.1.
When using a bearing at 75% or more of its rotation speed limit,
select the correct required grease type and amount or the correct
lubrication oil and method.
● Table 7.1 Correction Factors for Rotation Speed Limit of Duplex Bearings
No. of bearings in set
Extra-light preload (E)
Light preload (L)
Medium preload (M)
Heavy preload (H)
2 rows
3 rows
4 rows
0.83
0.78
0.63
0.54
0.73
0.68
0.54
0.39
0.78
0.73
0.59
0.44
26
Limiting Speeds
NACHI BEARING
Shaft and Housing Design
Technical Description
8
8-1 Shaft and Housing Fit
Appropriate inner ring and shaft fit, and outer ring and housing fit is
required in order to get the most performance out of a bearing.
Loose fit surfaces can result in rotation of the raceway rings on the
shaft or in the housing.
This is called "creep." When it occurs creep can cause premature
failure, vibration, and other trouble due to abnormal heat and wear,
from debris getting into the bearing. An interference fit is a good way
of preventing creep. For convenient installation the interference fit
in on the inner ring and shaft or on the outer ring and housing (not
both).
However, this cannot be done under certain conditions so bearing
fitting needs to be determined after carefully considering the
relationship between the shaft and housing and other factors.
Recommended fits for general operating conditions (inner ring
rotation) of precision bearings used for machine tools are shown in
Tables 8.1 through 8.3.
Bearing
Selection
● Table 8.1 Shafts and Recommended Fit
Shaft diameter
(mm)
Bearing type
Angular contact ball
bearings
Cylindrical roller bearings
(cylindrical bore)
Main spindle thrust
bearing
Ball screw support bearings
Unit: μm
Bearing accuracy class
Over
10
18
50
80
150
25
40
140
Class 5
Incl.
18
50
80
150
200
40
140
200
Class 4/Class 2
Desired fit
0~2T
0~2.5T
0~3T
0~4T
0~5T
−
−
−
Shaft tolerance
h4
h4
h4
js4
js4
js4
k4
k4
Desired fit
0~2T
0~2.5T
0~3T
0~4T
0~5T
−
−
−
For all shaft diameters
0~6L
h4
0~6L
h4
For all shaft diameters
0~10L
h5
0~10L
h5
Bearing type
Angular contact ball
bearings
Cylindrical roller bearings
Main spindle thrust
bearing
Ball screw support bearings
Angular contact ball
bearings
Cylindrical roller bearings
Ball screw support bearings
Shaft and
Housing
Design
Class 5
Class 4/Class 2
Desired fit
Desired fit
Housing bore
tolerance
18
50
50
120
120
180
180
250
Overall housing bore
0~3L
0~4L
0~5L
0~6L
±0
JS4
JS4
JS4
JS4
K5
0~3L
0~4L
0~5L
0~6L
±0
JS3
JS3
JS3
JS3
K5
Overall housing bore
30L~40L
K5
30L~40L
K5
Overall housing bore
10L~20L
H6
10L~20L
H6
Unit: μm
Bearing accuracy class
Housing bore diameter
(mm)
Class 5
Class 4/Class 2
incl.
Desired fit
Housing bore
tolerance
18
50
50
120
120
180
180
250
Overall housing bore
Overall housing bore
6L~10L
8L~13L
12L~18L
15L~22L
±0
10L~20L
H4
H4
H4
H4
K5
H6
Over
Lubrication
Unit: μm
● Table 8.3 Housings and Recommended Fit (Free Side)
Bearing type
Preload
and
Rigidity
Limiting
Speeds
Housing bore
tolerance
incl.
Bearing
Arrangement
Bearing accuracy class
Housing bore diameter
(mm)
Over
Bearing
Tolerance
Shaft tolerance
h3
h3
h3
js3
js3
js4
k3
k3
● Table 8.2 Housings and Recommended Fit (Fixed Side)
Bearing
Life
Desired fit
Housing bore
tolerance
6L~10L
8L~13L
12L~18L
15L~22L
±0
10L~20L
H3
H3
H3
H3
K4
H6
Note) In Tables 8.1 through 8.3, "L" following a value indicates loose or clearance fit, while "T" indicates tight or interference fit.
Shaft and Housing Design
27
Bearing
Handling
Technical Description
Shaft and Housing Design
8-2 Recommended Accuracy for Shaft and Housing
In order to maintain mechanical performance of the main spindle
of a machine tool, the accuracy of installation and of installed
components must be equal to or higher than bearing accuracy.
The recommended bearing installation section accuracy and surface
roughness are shown in Tables 8.4 to 8.7.
● Table 8.4 Shaft Accuracy
● Table 8.6 Housing Accuracy
Accuracy item
Roundness
c, a
Cylindricity
,b
Vibration
,c
Concentricity
,d
Unit: μm
Shaft diameter
Over
−
10
18
30
50
80
120
180
−
10
18
30
50
80
120
180
−
10
18
30
50
80
120
180
−
10
18
30
50
80
120
180
Bearing accuracy class
Incl.
10
18
30
50
80
120
180
250
10
18
30
50
80
120
180
250
10
18
30
50
80
120
180
250
10
18
30
50
80
120
180
250
Class 5
1.3
1.5
2.0
2.0
2.5
3.0
4.0
5.0
1.3
1.5
2.0
2.0
2.5
3.0
4.0
5.0
2.0
2.5
3.0
3.5
4.0
5.0
6.0
7.0
4.0
5.0
6.0
7.0
8.0
10.0
12.0
14.0
Class 4
0.8
1.0
1.3
1.3
1.5
2.0
2.5
3.5
0.8
1.0
1.3
1.3
1.5
2.0
2.5
3.5
2.0
2.5
3.0
3.5
4.0
5.0
6.0
7.0
4.0
5.0
6.0
7.0
8.0
10.0
12.0
14.0
Class 2
0.5
0.6
0.8
0.8
1.0
1.3
1.8
2.3
0.5
0.6
0.8
0.8
1.0
1.3
1.8
2.3
1.3
1.5
2.0
2.0
2.5
3.0
4.0
5.0
2.5
3.0
4.0
4.0
5.0
6.0
8.0
10.0
● Table 8.5 Shaft Fitting Surface Roughness (Ra)
Over
−
10
18
30
50
80
120
180
−
10
18
30
50
80
120
180
−
10
18
30
50
80
120
180
−
10
18
30
50
80
120
180
Roundness
c, a1
Cylindricity
, b1
Vibration
, c1
Concentricity
, d1
Shaft diameter
d
Class 5
Class 4
Class 2
d ≤ 80mm
0.2
0.2
0.1
d > 80mm
0.4
0.4
0.2
Housing bore diameter
D
D ≤ 80mm
80mm < D ≤ 250mm
D > 250mm
Class 5
1.3
1.5
2.0
2.0
2.5
3.0
4.0
5.0
1.3
1.5
2.0
2.0
2.5
3.0
4.0
5.0
2.0
2.5
3.0
3.5
4.0
5.0
6.0
7.0
4.0
5.0
6.0
7.0
8.0
10.0
12.0
14.0
Class 4
0.8
1.0
1.3
1.3
1.5
2.0
2.5
3.5
0.8
1.0
1.3
1.3
1.5
2.0
2.5
3.5
2.0
2.5
3.0
3.5
4.0
5.0
6.0
7.0
4.0
5.0
6.0
7.0
8.0
10.0
12.0
14.0
Bearing accuracy class
Class 5
0.4
0.8
1.6
Class 4
0.4
0.8
1.6
Class 2
0.2
0.4
0.8
b1
c1 AB
c1 AB
A
B
c AB
28
Shaft and Housing Design
Class 2
0.5
0.6
0.8
0.8
1.0
1.3
1.8
2.3
0.5
0.6
0.8
0.8
1.0
1.3
1.8
2.3
1.3
1.5
2.0
2.0
2.5
3.0
4.0
5.0
2.5
3.0
4.0
4.0
5.0
6.0
8.0
10.0
c a1
dA
b
Incl.
10
18
30
50
80
120
180
250
10
18
30
50
80
120
180
250
10
18
30
50
80
120
180
250
10
18
30
50
80
120
180
250
Bearing accuracy class
● Table 8.7 Housing Fitting Surface Roughness (Ra)
Bearing accuracy class
c a
Accuracy item
Unit: μm
Housing bore diameter
A
d1 A
B
NACHI BEARING
Technical Description
8-3 Chamfer Dimension Limits
● Table 8.8 Chamfer Dimensions for Radial Bearings (Excluding Tapered Roller Bearings)
1.1
1.5
2
2.1
2.5
3
4
5
6
7.5
9.5
12
15 19
−
−
−
−
−
40
−
40
−
50
−
120
−
120
−
80
220
−
280
−
100
280
−
280
−
−
−
−
−
−
−
−
−
0.1
0.16
0.2
0.3
0.5
0.6
0.8
1
1.3
1.5
1.9
2
2.5
2.3
3
3
3.5
3.8
4
4.5
3.8
4.5
5
5
5.5
6.5
8
10
12.5
15
18
21
25
0.2
0.3
0.4
0.6
0.8
1
1
2
2
3
3
3.5
4
4
5
4.5
5
6
6.5
7
6
6
7
8
8
9
10
13
17
19
24
30
38
0.05
0.08
0.1
0.15
0.2
Bearing bore or
outside diameter
surface
0.3
r(maximum) or
r1(maximum)
(Radial direction)
−
−
−
−
−
−
40
−
40
−
50
−
120
−
120
−
80
220
−
280
−
100
280
−
280
−
−
−
−
−
−
−
−
Max
r(maximum) or
r1(maximum)
Axial direction
r1
1
Radial
direction
or
m)
mu )
ini um
0.6
Incl.
(
0.3
Over
r (m inim
m
0.05
0.08
0.1
0.15
0.2
Nominal bearing bore
diameter
Side face of inner/outer
ring or center washer
Smallest permissible
chamfer dimensions of
inner and outer rings
r (min) or r1 (min)
Unit: mm
Smallest permissible
(Reference)
chamfer dimensions of inner
Shaft or housing fillet
and outer rings
radius ra
r (max) or r1 (max)
Bearing
Selection
r (minimum) or
r1 (minimum)
Bearing
Life
Bearing
Tolerance
(Axial direction)
0.6
1
r: Chamfer dimensions of inner ring and outer ring
r1: Chamfer dimensions of inner ring and outer ring
(front face etc.) or of center ring of thrust ball
bearing
Bearing
Arrangement
1
Preload
and
Rigidity
1.5
Lubrication
2
Limiting
Speeds
2
Shaft and
Housing
Design
2
Bearing
Handling
2.5
3
4
5
6
8
10
12
15
Note
a Exact shape of chamfer is not specified. Limits
fall within radial and axial minimum radius and
maximum radius.
b r (minimum) values in the axial direction of
bearings with nominal bearing widths of 2 mm
or less r (max) are the same as those in the
radial direction.
Shaft and Housing Design
29
Technical Description
9
Bearing Handling
9-1 Storing and Transporting Bearings
Rolling contact bearings are precision components. It is important
to handle them with care to avoid damage due to impact. Rolling
contact bearings also are susceptible to dirt and rust, so care is
required during storage and transport.
● When storing bearings, select a cool, dry location that is not
exposed to direct sunlight or humidity.
● Do not leave bearings on the floor. Store them at a height of at
least 30 cm, and avoid exposure to dust.
● First-in, first-out storage should always be used for bearing
inventory management. Arrange bearings so those with the
oldest packing date can be used first.
● Take care bearings being transported are not crushed or
dropped, etc., protect them from damage and deformation due
to impact, and ensure they do not become soiled due to broken
packing materials.
9-2 Assembling Bearings
The quality of bearing installation influences precision, service life,
performance, and other factors, so care is required. The following is
the procedure for assembly work.
a Shaft and housing inspection
b Unpacking and cleaning
c Assembly
d Post assembly check
9.2.1 Shaft and Housing Inspection
● Clean the shaft and housing thoroughly and remove any dirt
and debris. Also, confirm there are no burrs.
● Confirm that the shaft and housing are finished in accordance
with the drawings, and check and record dimensions, shoulder
squareness, and the corner radius. As shown in Figure 9.1,
measure the shaft diameter and housing bore at two locations
in the axial direction and four locations radially.
1
2
3
A
● After washing, shake the oil from the bearing and then cover it.
Do not rotate a bearing that has been degreased.
9.2.3 Assembly
Generally the majority of bearings assembled into machine tools
have interference shaft fits and loose housing fits. The methods used
for mounting bearings to shafts are the shrink and press fits.
Shrink fits
With this mounting method, the bearing is heated until it expands
larger than the shaft and the inner ring can be slipped onto the shaft.
An electromagnetic heater with degausser (Figure 9.2) avoids undue
stress to the inner ring, while an oven helps to shorten process time.
Heating temperature must be no greater than 120°C.
Temperatures greater than 120°C can decrease bearing hardness
and shortens its service life.
After a heated bearing is installed on a shaft, it contracts axially as
it cools, which can cause a gap between the inner ring and shaft
shoulder (Figure 9.3), so positioning is achieved using a nut, etc.
B
4
1
2
3
A
B
4
● Figure 9.1 Shaft Diameter and Housing Diameter Measurement Locations
● Figure 9.2 Induction Heater
9.2.2 Unpacking and Cleaning
● Do not unpack a bearing until just before you are ready to use
it. Be sure to wear vinyl gloves when unpacking a bearing.
Unpacking a bearing with bear hands or while wearing fabric
gloves creates the risk of rust or lint intrusion.
● Apply anti-rust oil to the surface of the unpacked bearing. Wash
the bearing with white kerosene. For washing, prepare either
a filtered shower or two containers with raised wire mesh
bottoms, one for basic washing and one for finish washing.
● Figure 9.3 Shaft Shoulder Gap After Cooling
30
Bearing Handling
NACHI BEARING
Reference: Press fit force and removal force
Though the force required to press fit a bearing inner ring to and
removing it from the shaft depends on interference amounts and the
shaft surface finish, general values can be obtained using Formula
9.1.
(Formula 9.1)
Ka
: Press fit force (removal force) (kN)
fk
: Installation/removal condition coefficient (Table 9.1)
Δde
B
d
di
: Effective interference (mm)
: Nominal inner ring width (mm)
: Nominal bearing bore diameter (mm)
: Inner ring mean outside diameter (mm)
Cylindrical roller bearing
Bearing
Selection
Bearing
Life
Bearing
Tolerance
Other bearings
Bearing
Arrangement
Here, D = Nominal bearing outside diameter (mm)
● Figure 9.4 Inner Ring Press Fitting
Preload
and
Rigidity
● Table 9.1 Installation/Removal Condition Coefficient
Conditions
Risk of ball damage
Technical Description
Press fits
With this method, a tool is placed on the inner ring side surface and
a jack or press is used to press fit (Figure 9.4). When press fitting
the inner ring on a shaft do not apply force to the outer ring or cage.
In the case of an angular contact ball bearing, application of force
in the opposite direction of the contact angle direction should be
avoided because it will damage the raceway shoulder (Figure 9.5).
fk (mean value)
Inner ring press fit to cylindrical solid shaft
39
Inner ring removal from cylindrical solid shaft
59
Lubrication
Limiting
Speeds
Note) Values when shaft bore and shaft are thinly coated with oil.
Shaft and
Housing
Design
Bearing
Handling
● Figure 9.5 Angular Contact Ball Bearing Assembly Direction
Reference: Maximum radial run-out locations
The maximum radial run-out locations of the inner ring and outer
ring are indicated by "c" marks on the ring face. Axial run-out can
be minimized by aligning the minimum radial run-out location of the
axis with the "c" mark on the inner ring. The outer ring also should
be assembled so its "c" mark is aligned with the minimum run-out
locations of the housing.
Note that there is no relationship between the outside ring
"c" mark position and the outside diameter "<" mounting mark
position.
Maximum radial run-out surface
● Figure 9.6 Maximum Radial Run-out Locations
Bearing Handling
31
Technical Description
Bearing Handling
Mounting on a shaft
Normally a shaft nut is used to secure the inner ring of the bearing to
the shaft.
It is necessary to ensure that the shaft nut side surface is at the
proper angle relative to the thread. If the surfaces are not square
tightening of the shaft nut can result in bending of the shaft.
Also, adjustment of the shaft nut is required when tightening it
because of edge contact due to a gap in the mating surface between
the shaft nut and the shaft.
Tightening with the shaft nut makes it possible to apply a specific
tightening force by controlling the tightening torque. Though there is
a discrepancy in the relationship between shaft nut tightening torque
and the tightening force due to the accuracy and roughness of each
threaded portion, it can be expressed as Formula 9.2.
The recommended mounting force for each bearing bore is shown in
Table 9.2.
Mounting on a housing
In order to secure the outer ring of a bearing in the axial direction,
clearing normally is maintained between the press-fit cover and
housing and a bolt is used for tightening. Caution is required because
outer ring misalignment and deformation can occur bolts are not
tightened correctly or uniformly (Figure 9.7).
Generally an outside ring clearance reduction gap D of 0.010 to 0.020
is recommended. Recommended clearance reduction gap values
for a face-to-face ball support bearing (TAB Series, TAF Series) are
shown in Tables 9.3 and 9.4.
Δ+2A
2A clearance
Housing
Press-fit cover
A
A
(Formula 9.2)
F
Mn
d2
E
P
U
D
dn
μm
μ
: Tightening force (N)
: Tightening torque (N·mm)
Δ =0.010mm
: Thread nominal diameter (mm)
: Lead angle
● Table 9.3 Recommended Clearance Reduction Gap Values for Ball
Screw Support Bearings (TAB Series)
: Pitch (mm)
: Thread surface friction angle
Bearing no.
: Half-angle of thread
: Mean diameter of nut bearing surface (mm)
: Coefficient of friction of nut bearing surface (| 0.15)
: Coefficient of friction of thread surface (| 0.15)
● Table 9.2 Recommended Shaft Nut Tightening Force Values
Nominal
bearing bore
diameter
(mm)
10
12
15
17
20
25
30
35
40
45
50
55
60
65
70
75
32
Shaft nut tightening
force
(N)
Bearing Handling
1500
2500
2500
2500
4900
4900
4900
4900
9800
9800
9800
14700
14700
14700
14700
14700
Δ =0.050mm
● Figure 9.7 Example of Raceway Deflection Depending on Outer Ring
Clearance Reduction Gap
Nominal
bearing bore
diameter
(mm)
80
85
90
95
100
105
110
120
130
140
150
160
170
180
190
200
Shaft nut tightening
force
(N)
19600
19600
19600
19600
19600
19600
19600
19600
19600
29400
29400
29400
29400
29400
29400
29400
15TAB04 DF
17TAB04 DF
20TAB04 DF
25TAB06 DF
30TAB06 DF
35TAB07 DF
40TAB07 DF
40TAB09 DF
45TAB07 DF
45TAB10 DF
50TAB10 DF
55TAB10 DF
55TAB12 DF
60TAB12 DF
External ring clearance reduction gap ' (mm)
0.010 ~ 0.030
0.010 ~ 0.040
0.020 ~ 0.050
0.020 ~ 0.060
● Table 9.4 Recommended Clearance Reduction Gap Values for Ball
Screw Support Bearings (TAF Series)
Bearing no.
External ring clearance reduction gap ' (mm)
25TAF06 DF
30TAF07 DF
35TAF09 DF
40TAF09 DF
40TAF11 DF
45TAF11 DF
50TAF11 DF
60TAF13 DF
60TAF17 DF
80TAF17 DF
100TAF21 DF
120TAF03 DF
0.020
0.030
0.040
0.050
NACHI BEARING
Technical Description
Tapered bore cylindrical roller bearing clearance adjustment
The internal clearance of a tapered bore cylindrical roller bearing can
be adjusted by the spacer width using the procedure below.
a Check the shaft taper. Coat the taper with a thin layer of bluing;
80% or more contact is required.
b Lightly place the inner sub-unit onto the shaft taper (Figure 9.8).
d Place the outer ring and fix the shaft horizontally.
f Touch the center the outer ring with a dual gauge probe.
g Pressing down on the outer ring from above, rotate it left and
right a few times so it fits well, and then zero set the dial gauge.
h Push the outer ring straight up 180° from its position of
symmetry (directly below), and rotate it slightly left and right to
take a reading of its maximum value (Figure 9.9).
i Change the position of the shaft at steps of approximately 30°,
measure the axial displacement, and calculate the average of the
readings as the value of D R.
j Use a block gauge to measure the length to the inner ring edges
surface and shaft shoulder (Figure 9.10).
k Change the position and use the average of five or six locations
as the value for L'.
l Use Formula 9.3 to determine the wide dimension of the required
spacer.
● Figure 9.8 Inner Sub-unit Temporary Tightening
Bearing
Selection
Bearing
Life
Bearing
Tolerance
Bearing
Arrangement
Preload
and
Rigidity
(Formula 9.3)
Lubrication
L’
ΔR
Δ
Oe
: Average spacer width obtained in step k
: Measured radial clearance
: Desired post-assembly radial clearance
: External ring contraction ratio
Limiting
Speeds
Shaft and
Housing
Design
● Figure 9.9 Radial Clearance Measurement
Bearing
Handling
Block gauge
D
De
Dh
G
: Inner ring outside diameter (mm)
: Inner ring bore (mm)
: Housing bore (mm)
: Outer ring interference
m Correct the spacer width dimension.
n Remove the inner sub-unit from the shaft. This time avoid striking
the inner ring with strong force. Use of a special removal tool to
make ring removal easy.
o Install the spacer and bearing onto the shaft.
p Again, measure the radial clearance and confirm that the desired
radial clearance is provided (Figure 9.11).
● Figure 9.10 Spacer Temporary Width Dimension Measurement
9.2.4 Post Assembly Check
Use the procedure under "5-3 Measuring Preload" (page 14) to
confirm that the prescribed preload is being applied.
● Figure 9.11 Final Assembly Radial Clearance Check
Bearing Handling
33
Technical Description
Bearing Handling
9-3 Running Test
After installing bearings, a test run is performed to confirm that
operation is normal. Particularly when using grease lubrication the
grease must be allowed to get inside the bearing, and so sufficient
break-in running is required.
The following is the general running test procedure.
a Check to make sure there is no gap between the shaft and
housing or the cover or that all the gaps are uniform.
b First rotate manually any rotatable mechanisms and check for
abnormal noise and sticking.
c For large mechanisms that cannot be rotated manually, start at a
speed that is as low as possible then do the same checks as step
b while coasting.
d If no abnormalities are discovered during the first three steps above,
gradually increase speed up to normal operating speed while
confirming that the rise in temperature is within normal conditions.
e For long term operation, check for bolt and nut looseness, oil and
grease leaks, and abnormal noise. If possible, after completing
the test run drain the lubricant and check for the presence of
foreign matter.
f Actual operation can be started after completing the run in test.
9-4 Removing Bearings
Though the main reasons for removing bearings is periodic
maintenance and mechanical breakdown, it also should be used as
an opportunity to check the current status of a machine and to use
what is learned for improvements, etc. Particularly in the case of
malfunction, the key reasons for the breakdown usually can be found
after disassembly. Because of this, the following points should be
checked when removing bearings.
a Problems with bearing installation
b Insufficient lubricating oil or grease, and the amount of
contaminants present (Collect samples.)
34
Bearing Handling
c Inner ring and outer ring fit
d Bearing trouble
The following items also need to be settled before starting bearing
removal.
a Bearing removal method
b Fitting conditions
c Tools required for removal
Dimension Tables
Dimension Tables
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
Precision Rolling Bearings
Angular Contact Ball Bearings
High-speed Angular Contact Ball Bearings
Thrust Load Angular Contact Ball Bearings
Multiple-row Cylindrical Roller Bearings
Cross Tapered Roller Bearings
Ball Screw Support Bearings
36
Precision Rolling Bearing Types and Designs
NACHI BEARING
Precision Rolling Bearing
Types and Designs
Dimension Tables
Type
Angular contact ball
bearings
High-speed angular
contact ball bearings
Cross section
Bearing
series
7900C
Contact
angle
15°
7900AC
25°
7000C
15°
7000AC
25°
7200C
15°
7200AC
25°
BNH
15°
TAH
30°
Thrust load angular
contact ball bearings
NN type multiplerow cylindrical roller
bearings
TBH
40°
NN3000
−
Description
● Balls and the inner ring and outer ring raceways are designed for contact in a
specific contact angle, which means this type of bearing is suitable for composite
loads (axial load and radial load).
● The contact angle means that axial force components are generated when a radial
load is applied, so these bearings are normally used in pairs at either end of a
shaft.
● A contact angle of 15° is best for high speed, while a contact angle of 25° is
better for axial loads.
● Since ball slipping is reduced by the gyro-moment at high-speeds, the ball
diameter of this type of bearing is smaller than that of a standard angular contact
ball bearing.
● This type of bearing is dimensionally interchangeable with the 7000 Series, and
can be used for their replacement.
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
● The contact angle of this type is smaller than that of the previous TAD Series
(double-direction thrust angular contact ball bearings), for less gyro-moment
induced ball sliding and lower temperature.
● Can be used to replace TAD Series bearings.
TAB
TAF
● A large number of rollers (cylindrical) for high rigidity.
● Tapered bore allows adjustment of the internal clearance.
● Oil groove and oil hole in the center of the outer ring width are also available.
NNU type multiplerow cylindrical roller
bearings
NNU4900
−
Cross tapered roller
bearings
XRN
XRG
−
● Designed as an alternate to tapered roller bearings, this series provides high axial
load and moment load rigidity.
● Rollers have rotational and orbital centers for smooth rotation.
TAB
60°
● Mainly used in machine tool ball screw support applications.
● Open type and sealed type (contact type, non-contact type) available.
TAF
50°
(55°)
● Mainly used in machine tool high load ball screw support applications for electric
injection molding machines.
● Large-diameter balls provide a large contact angle for high thrust load capacity.
Ball screw support
bearings
Precision Rolling Bearing Types and Designs
Types
Types
and
and
Designs
Designs
37
Angular Contact Ball Bearings
Standard Type
38
Angular Contact Ball Bearings
NACHI BEARING
Nomenclature of Bearing Numbers
Tolerance class code
P5 : JIS Class 5
P4 : JIS Class 4
Cage code
Y : Polyamide resin cage
Contact angle code
C : 15°
AC : 25°
Preload and other class codes
/GE : Extra-light preload
/GL : Light preload
/GM : Medium preload
/GH : Heavy preload
Mounting code
U : Flush ground (Single)
DU : Flush ground (duplex)
DB : Back-to-back
DF : Face-to-face
DT : Tandem
● With angular contact ball bearings, the balls and the inner ring and
outer ring raceways form a specific angle of contact. When used
in a single configuration, axial load is limited to a single direction,
this type of bearing is suitable for bearing composite loads made
up of axial and radial loads.
● Since this type of bearing has a contact angle, axial components
are generated when a radial load is applied. Because of this, this
type of bearing is normally used in pairs at either end of a shaft.
● Ceramic ball type also available.
Contact Angle
Two contact angles are available: 15° and 25°. 15° is for high-speed
applications. 25° is for applications requiring high axial rigidity.
Cage
A ball guide polyamide cage is provided as standard. The polyamide
cage should be used under temperatures lower than 120°.
Dimensional Accuracy, Rotational Accuracy
Conforms to JIS Class 5 or Class 4. See page 7 for details.
Preload
● Four types of standard preload settings are available. Use the
nearby table to select the preload that meets your criteria.
● See page 16 through 18 for standard preloads available for each
series and size.
7900
7000
7200
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
Preload Selection Criteria
Preload code
E (extra-light preload)
L (light preload)
M (medium preload)
H (heavy preload)
Types
and
Designs
BNH
Bore diameter number
Dimension series number 00 : 10 mm bore dimension
01 : 12mm
9 : 19 Series
Bearing type
02 : 15mm
0
:
10
Series
7 : Single-row angular contact ball bearing
Material code
03 : 17mm
2 : 02 Series
SH6- : Inner ring/Outer ring = Bearing steel; Ball = Ceramic
04+ : (bore number) ×5 mm
(No code): Inner ring/Outer ring/Balls = Bearing steel
Features
Dimension Tables
SH6- 7 2 08 C Y DU /GL P4
Selection criteria
Prevents mechanical vibration and increases accuracy.
Provides rigidity at high-speed (dmn value = 500,000) operation.
Provides higher than light preload rigidity at standard-speed operation.
Provides maximum rigidity at low-speed operation.
Mounting
See page 12 and 13 for multiple-row arrangements.
Ceramic Ball Types
Bearings with ceramic balls that are less dense than bearing steel balls also
are available for lower centrifugal force when balls rotate at high speeds.
● The characteristics of ceramic and bearing steel are shown in the
table below.
● The bearing number of a bearing that uses ceramic balls starts with "SH6-".
● Preload and axial rigidity is approximately 1.2 times that of
bearing steel type bearings.
Comparison of Ceramic and Bearing Steel Characteristics
°C
g/cc
Ceramic
(Si3N4)
800
3.2
Bearing steels
(SUJ2)
180
7.8
1/°C
3.2×10-6
12.5×10-6
Hv
1400~1700
700~800
GPa
314
206
Features
Unit
Heat resistance
Density
Linear expansion
coefficient
Hardness
Longitudinal
elastic coefficient
Poisson's ratio
Corrosion resistance
Magnetism
Conductivity
Crystal chemical bonding
−
−
−
−
−
0.26
0.30
Good
No good
Non-magnetic substance Strongly magnetic substance
Insulator
Conductor
Covalent
Metallic
Angular Contact Ball Bearings
39
Dimension Tables
Angular Contact Ball Bearings
7900C Series
7900AC Series
Contact angle D = 15°
Contact angle D = 25°
B
r
r1
r
r
D
d
D
a
Back-to-back (DB)
Bearing no.
40
d
D
B
r
(Min)
Face-to-face (DF)
r1
(Min)
Load center
a
(mm)
Basic dynamic
load rating
Cr
(kN)
Boundary dimensions (mm)
Tandem (DT)
Basic static load
rating
Cor
(kN)
7900C
10
22
6
0.3
0.15
-0.9
3.00
1.52
7900AC
10
22
6
0.3
0.15
0.7
2.88
1.45
7901C
7901AC
12
12
24
6
0.3
0.15
-0.6
3.20
1.72
24
6
0.3
0.15
1.2
3.05
1.63
7902C
7902AC
15
15
28
28
7
7
0.3
0.3
0.15
0.15
-0.6
1.5
4.75
4.55
2.64
2.53
7903C
7903AC
7904C
7904AC
17
17
20
20
30
7
0.3
0.15
-0.3
5.00
2.95
30
7
0.3
0.15
2.1
4.75
2.82
37
9
0.3
0.15
-0.7
7.30
4.55
37
9
0.3
0.15
2.1
6.95
4.35
7905C
7905AC
25
25
42
9
0.3
0.15
0.1
7.80
5.45
42
9
0.3
0.15
3.5
7.40
5.15
7906C
30
47
9
0.3
0.15
0.7
8.30
6.25
7906AC
7907C
7907AC
7908C
7908AC
30
35
35
40
40
47
9
0.3
0.15
4.5
7.85
5.95
55
10
0.6
0.3
1.0
12.5
55
10
0.6
0.3
5.5
11.9
62
62
12
12
0.6
0.6
0.3
0.3
0.8
5.9
15.7
14.9
12.4
11.8
7909C
7909AC
7910C
45
45
50
68
12
0.6
0.3
1.6
16.6
14.1
68
12
0.6
0.3
7.2
15.7
13.3
72
12
0.6
0.3
2.2
17.7
15.5
7910AC
50
72
12
0.6
0.3
8.2
16.4
14.9
Angular Contact Ball Bearings
9.65
9.20
NACHI BEARING
R1
R
R
R
d1
D1
R
D1
d2
d2
d1
D1
D1
d1
Dimension Tables
73000
63500
64800
56400
54300
47200
49700
43200
41000
35600
34800
30300
30300
26300
25900
22500
22900
19900
20600
18000
19100
16600
d2
Back-to-back
Rotation speed limit (rpm)
Grease
lubrication
D1
D1
Single row
R
Face-to-face
Corner radius (mm)
Oil lubrication
D1
(Min)
d1
(Max)
d2
(Max)
R
(Max)
R1
(Max)
Mass
(kg)
(Reference)
Bearing no.
100000
85000
88800
75500
74400
63200
68000
57800
56100
47700
47700
40600
41500
35300
35500
30200
31300
26600
28300
24000
26200
22300
12.5
12.5
14.5
14.5
17.5
17.5
19.5
19.5
22.5
22.5
27.5
27.5
32.5
32.5
39.5
39.5
44.5
44.5
49.5
49.5
54.5
54.5
19.5
19.5
21.5
21.5
25.5
25.5
27.5
27.5
34.5
34.5
39.5
39.5
44.5
44.5
50.5
50.5
57.5
57.5
63.5
63.5
67.5
67.5
20.8
20.8
22.8
22.8
26.8
26.8
28.8
28.8
35.8
35.8
40.8
40.8
45.8
45.8
52.5
52.5
59.5
59.5
65.5
65.5
69.5
69.5
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.008
0.008
0.010
0.010
0.015
0.015
0.016
0.016
0.035
0.035
0.041
0.041
0.046
0.046
0.074
0.074
0.107
0.107
0.127
0.127
0.128
0.128
7900C
7900AC
7901C
7901AC
7902C
7902AC
7903C
7903AC
7904C
7904AC
7905C
7905AC
7906C
7906AC
7907C
7907AC
7908C
7908AC
7909C
7909AC
7910C
7910AC
Angular Contact Ball Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
41
Dimension Tables
Angular Contact Ball Bearings
7000C Series
7000AC Series
Contact angle D = 15°
Contact angle D = 25°
B
r
r1
r
r
D
d
D
a
Back-to-back (DB)
Bearing no.
42
d
D
B
r
(Min)
Face-to-face (DF)
r1
(Min)
Load center
a
(mm)
Basic dynamic
load rating
Cr
(kN)
Boundary dimensions (mm)
Tandem (DT)
Basic static load
rating
Cor
(kN)
7000C
10
26
8
0.3
0.15
-1.9
5.35
2.50
7000AC
7001C
10
12
26
8
0.3
0.15
0.2
5.15
2.41
28
8
0.3
0.15
-1.7
5.80
2.91
7001AC
12
28
8
0.3
0.15
0.7
5.60
2.79
7002C
7002AC
7003C
7003AC
7004C
7004AC
15
15
17
17
20
20
32
9
0.3
0.15
-1.8
6.65
3.70
32
9
0.3
0.15
1.0
6.30
3.55
35
35
10
10
0.3
0.3
0.15
0.15
-2.0
1.1
7.00
6.65
4.15
3.95
42
12
0.6
0.3
-2.4
11.2
6.60
42
12
0.6
0.3
1.2
10.6
6.25
7005C
25
47
12
0.6
0.3
-1.8
12.9
8.65
7005AC
25
47
12
0.6
0.3
2.4
11.7
7.60
7006C
7006AC
30
30
55
13
1
0.6
-1.6
16.0
11.1
55
13
1
0.6
3.4
15.1
10.5
7007C
7007AC
7008C
7008AC
7009C
7009AC
35
35
40
40
45
45
62
14
1
0.6
-1.4
19.3
13.7
62
14
1
0.6
4.3
18.2
13.0
68
15
1
0.6
-1.3
20.7
16.0
68
15
1
0.6
5.1
19.5
15.1
75
75
16
16
1
1
0.6
0.6
-1.1
6.0
24.6
23.1
19.4
18.3
7010C
7010AC
7011C
50
50
55
80
16
1
0.6
-0.5
26.2
22.0
80
16
1
0.6
7.2
23.7
19.7
90
18
1.1
0.6
-0.6
34.5
28.8
7011AC
7012C
7012AC
7013C
55
60
60
65
90
18
1.1
0.6
7.9
31.0
25.6
95
18
1.1
0.6
-0.1
35.5
30.5
95
18
1.1
0.6
9.1
32.0
27.6
100
18
1.1
0.6
0.5
37.5
34.5
7013AC
7014C
7014AC
7015C
7015AC
65
70
70
75
75
100
18
1.1
0.6
10.2
34.0
31.0
110
20
1.1
0.6
0.4
47.0
43.0
110
115
20
20
1.1
1.1
0.6
0.6
11.0
1.0
44.5
48.5
41.0
46.0
115
20
1.1
0.6
12.2
45.5
43.0
7016C
7016AC
7017C
7017AC
7018C
80
80
85
85
90
125
22
1.1
0.6
0.8
59.0
55.5
125
22
1.1
0.6
12.9
55.5
52.5
130
22
1.1
0.6
1.4
60.5
59.0
130
22
1.1
0.6
14.1
57.0
55.5
140
24
1.5
1
1.3
72.0
69.5
7018AC
90
140
24
1.5
1
14.8
68.0
65.5
7019C
7019AC
7020C
95
95
100
145
24
1.5
1
1.9
74.0
73.5
145
24
1.5
1
16.0
69.5
69.5
150
24
1.5
1
2.4
76.0
77.5
7020AC
100
150
24
1.5
1
17.2
71.0
73.0
Angular Contact Ball Bearings
NACHI BEARING
R1
R
R
R
d1
D1
R
D1
d2
d1
D1
D1
d1
Dimension Tables
65000
56500
58500
51000
49500
43000
45000
39000
37500
32500
32500
28200
27400
23900
24100
21000
21600
18800
19500
16900
18000
15600
16100
14000
15000
13100
14200
12300
13000
11300
12300
10700
11400
9900
10900
9400
10100
8800
9700
8400
9300
8100
d2
Back-to-back
Rotation speed limit (rpm)
Grease
lubrication
D1
d2 D1
Single row
R
Face-to-face
Corner radius (mm)
Oil lubrication
D1
(Min)
d1
(Max)
d2
(Max)
R
(Max)
R1
(Max)
Mass
(kg)
(Reference)
Bearing no.
89000
75500
80000
68000
68000
58000
61500
52500
51500
44000
44500
37500
37500
32000
33000
28000
29600
25200
26700
22700
24600
20900
22100
18800
20600
17500
19400
16500
17800
15100
16800
14300
15600
13300
14900
12700
13900
11800
13300
11300
12800
10900
12
12
14
14
17
17
19
19
24
24
29
29
35
35
40
40
45
45
50
50
55
55
61
61
66
66
71
71
76
76
81
81
86
86
91
91
97
97
102
102
107
107
24
24
26
26
30
30
33
33
38
38
43
43
50
50
57
57
63
63
70
70
75
75
84
84
89
89
94
94
104
104
109
109
119
119
124
124
133
133
138
138
143
143
25
25
27
27
31
31
34
34
40
40
45
45
52
52
59
59
65
65
72
72
77
77
86
86
91
91
96
96
106
106
111
111
121
121
126
126
135.6
135.6
140.6
140.6
145.6
145.6
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.6
0.6
0.6
0.6
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1.5
1.5
1.5
1.5
1.5
1.5
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.3
0.3
0.3
0.3
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
1
1
1
1
1
1
0.022
0.022
0.024
0.026
0.035
0.035
0.045
0.045
0.079
0.079
0.091
0.091
0.135
0.135
0.170
0.170
0.210
0.210
0.265
0.265
0.285
0.285
0.420
0.420
0.450
0.450
0.470
0.470
0.660
0.660
0.695
0.695
0.925
0.925
0.960
0.960
1.26
1.26
1.36
1.36
1.37
1.37
7000C
7000AC
7001C
7001AC
7002C
7002AC
7003C
7003AC
7004C
7004AC
7005C
7005AC
7006C
7006AC
7007C
7007AC
7008C
7008AC
7009C
7009AC
7010C
7010AC
7011C
7011AC
7012C
7012AC
7013C
7013AC
7014C
7014AC
7015C
7015AC
7016C
7016AC
7017C
7017AC
7018C
7018AC
7019C
7019AC
7020C
7020AC
Angular Contact Ball Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
43
Dimension Tables
Angular Contact Ball Bearings
7200C Series
7200AC Series
Contact angle D = 15°
Contact angle D = 25°
B
r
r1
r
r
D
d
D
a
Back-to-back (DB)
Bearing no.
44
d
D
B
r
(Min)
Face-to-face (DF)
r1
(Min)
Load center
a
(mm)
Basic dynamic
load rating
Cr
(kN)
Boundary dimensions (mm)
Tandem (DT)
Basic static load
rating
Cor
(kN)
7200C
10
30
9
0.6
0.3
-2.2
6.95
3.30
7200AC
10
30
9
0.6
0.3
0.2
6.75
3.20
7201C
7201AC
12
12
32
10
0.6
0.3
-2.5
7.95
3.90
32
10
0.6
0.3
0.2
7.65
3.75
7202C
7202AC
15
15
35
11
0.6
0.3
-2.6
8.70
4.55
35
11
0.6
0.3
0.4
8.35
4.40
7203C
7203AC
7204C
7204AC
17
17
20
20
40
40
12
12
0.6
0.6
0.3
0.3
-2.7
0.8
10.9
10.5
5.90
5.65
47
14
1
0.6
-3.1
14.7
47
14
1
0.6
0.9
14.0
7205C
7205AC
25
25
52
15
1
0.6
-3.1
16.7
52
15
1
0.6
1.6
15.9
7206C
30
62
16
1
0.6
-2.7
23.2
14.9
7206AC
7207C
7207AC
7208C
30
35
35
40
62
16
1
0.6
2.8
22.0
14.1
72
17
1.1
0.6
-2.3
30.5
20.1
72
17
1.1
0.6
4
29.1
19.1
80
18
1.1
0.6
-2.1
36.5
25.4
7208AC
7209C
7209AC
7210C
40
45
45
50
80
85
18
19
1.1
1.1
0.6
0.6
5
-2.0
34.5
41.0
24.1
29.0
85
19
1.1
0.6
5.7
39.0
27.5
90
20
1.1
0.6
-1.9
43.0
32.0
7210AC
7211C
7211AC
7212C
7212AC
7213C
50
55
55
60
60
65
6.3
41.0
30.5
-1.6
53.0
40.0
7213AC
7214C
7214AC
7215C
8.15
7.80
10.3
9.80
90
20
1.1
0.6
100
21
1.5
1
100
21
1.5
1
7.6
50.5
38.0
110
22
1.5
1
-1.2
64.5
49.5
110
22
1.5
1
8.8
58.0
43.5
120
23
1.5
1
-0.8
73.5
59.0
65
70
70
75
120
23
1.5
1
10.1
66.5
52.0
125
125
24
24
1.5
1.5
1
1
-0.7
10.7
80.0
72.5
65.0
57.5
130
25
1.5
1
-0.7
83.5
70.0
7215AC
7216C
7216AC
7217C
75
80
80
85
130
25
1.5
1
11.4
75.5
62.5
140
26
2
1
-0.3
93.5
78.0
140
26
2
1
12.7
88.5
74.0
150
28
2
1
-0.4
7217AC
85
150
28
2
1
13.4
7218C
7218AC
7219C
90
90
95
160
30
2
1
-0.6
124
160
30
2
1
14.2
112
170
32
2.1
1.1
-0.7
133
115
7219AC
7220C
7220AC
95
100
100
170
32
2.1
1.1
14.9
126
107
180
180
34
34
2.1
2.1
1.1
1.1
-0.8
15.7
150
142
128
121
Angular Contact Ball Bearings
100
95.0
85.0
81.0
105
93.0
NACHI BEARING
R1
R
R
R
d1
D1
R
D1
d2
d1
D1
D1
d1
Dimension Tables
58500
51000
53000
46000
46500
40500
41000
35500
34500
30500
30000
26400
25200
22000
21800
19000
19500
16900
18000
15600
16700
14500
15000
13100
13700
12000
12600
11000
12000
10400
11400
9900
10600
9200
9900
8600
9300
8100
8800
7700
8300
7200
d2
Back-to-back
Rotation speed limit (rpm)
Grease
lubrication
D1
d2 D1
Single row
R
Face-to-face
Corner radius (mm)
Oil lubrication
D1
(Min)
d1
(Max)
d2
(Max)
R
(Max)
R1
(Max)
Mass
(kg)
(Reference)
Bearing no.
80000
68000
72500
62000
64000
54500
56000
47500
47500
40500
41500
35500
34500
29600
29900
25400
26700
22700
24600
20900
22900
19400
20600
17500
18800
16000
17300
14700
16400
13900
15600
13300
14500
12400
13600
11600
12800
10900
12100
10300
11400
9700
15
15
17
17
20
20
22
22
26
26
31
31
36
36
42
42
47
47
52
52
57
57
64
64
69
69
74
74
79
79
84
84
90
90
95
95
100
100
107
107
112
112
25
25
27
27
30
30
35
35
41
41
46
46
56
56
65
65
73
73
78
78
83
83
91
91
101
101
111
111
116
116
121
121
130
130
140
140
150
150
158
158
168
168
27.4
27.4
29.4
29.4
32.4
32.4
37.4
37.4
43.4
43.4
48.4
48.4
58.4
58.4
67
67
75
75
80
80
85
85
94.6
94.6
104.6
104.6
114.6
114.6
119.6
119.6
124.6
124.6
134
134
144
144
154
154
163
163
173
173
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
2
2
2
2
2
2
2
2
2
2
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
1
1
1
1
1
1
0.8
0.8
1
1
1
1
1
1
1
1
1
1
1
1
0.034
0.034
0.040
0.040
0.048
0.048
0.070
0.070
0.110
0.110
0.135
0.135
0.210
0.210
0.295
0.295
0.380
0.380
0.430
0.430
0.485
0.485
0.635
0.635
0.820
0.820
1.02
1.02
1.12
1.12
1.23
1.23
1.50
1.50
1.87
1.87
2.30
2.30
2.78
2.78
3.32
3.32
7200C
7200AC
7201C
7201AC
7202C
7202AC
7203C
7203AC
7204C
7204AC
7205C
7205AC
7206C
7206AC
7207C
7207AC
7208C
7208AC
7209C
7209AC
7210C
7210AC
7211C
7211AC
7212C
7212AC
7213C
7213AC
7214C
7214AC
7215C
7215AC
7216C
7216AC
7217C
7217AC
7218C
7218AC
7219C
7219AC
7220C
7220AC
Angular Contact Ball Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
45
High-speed Angular Contact Ball Bearings
BNH Series
46
High-speed Angular Contact Ball Bearings
NACHI BEARING
Nomenclature of Bearing Numbers
Tolerance class code
P4 : JIS Class 4 (standard)
P2 : JIS Class 2
Preload and other class codes
/GL : Light preload (standard)
Mounting code
U : Flush ground (Single)
DB : Back-to-back
DF : Face-to-face
DT : Tandem
Cage code
T : Phenolic resin cage (standard)
Y : Polyamide resin cage
Bore diameter number
07+: Bore dimension (bore number) ×5 mm
BNH000
Contact Angle
15° contact angle provided as standard.
Cage
Outer ring guided phenolic resin cage provided as standard. Ball
guide polyamide resin cage also available.
Dimensional Accuracy, Rotational Accuracy
JIS Class 4 compliance as standard. See page 7 for details.
BNH
XRN
XRG
TAB
TAF
Preload
7000C
7900
7000
7200
NN3000
NNU4900
Material code
SH6- : Inner ring/Outer ring = Bearing steel; Ball = Ceramic
(No symbol): Inner ring/Outer ring/Balls = Bearing steel
● Smaller machine steel balls, higher speeds, and lower
temperatures than previous angular contact ball bearings. Mainly
used for the main spindle of high-speed machining centers.
● Ceramic ball type also available.
Types
and
Designs
TAH
TBH
Dimension series number
0 : 10 Series
Bearing type
BNH : BNH Series angular contact ball bearing
Features
Dimension Tables
SH6- BNH 0 10 T DB /GL P4
Light preload as standard. See page 19 for information about
preloads.
Ceramic Ball Types
● Bearings with ceramic balls that are less dense than bearing steel
balls also are available for lower centrifugal force when balls
rotate at high speeds.
● The characteristics of ceramic and bearing steel are shown in the
table below.
● The bearing numbers of bearings that use ceramic balls start with
"SH6-".
● Preload and axial rigidity is approximately 1.2 times that of
bearing steel type bearings.
Comparison of Ceramic and Bearing Steel Characteristics
°C
g/cc
Ceramic
(Si3N4)
800
3.2
Bearing steels
(SUJ2)
180
7.8
1/°C
3.2×10-6
12.5×10-6
Hv
1400~1700
700~800
GPa
314
206
Features
Unit
Heat resistance
Density
Linear expansion
coefficient
Hardness
Longitudinal
elastic coefficient
Poisson's ratio
Corrosion resistance
Magnetism
Conductivity
Crystal chemical bonding
−
−
−
−
−
0.26
0.30
Good
No good
Non-magnetic substance Strongly magnetic substance
Insulator
Conductor
Covalent
Metallic
High-speed Angular Contact Ball Bearings
47
Dimension Tables
High-speed Angular Contact Ball Bearings BNH Series
Contact angle 15°
B
r
r1
r
15˚
Id
ID
r
a
r1
(Min)
Load center
a
(mm)
Basic dynamic
load rating
Cr
(kN)
Boundary dimensions (mm)
Bearing no.
48
d
D
B
r
(Min)
Basic static load
rating
Cor
(kN)
BNH007
35
62
14
1
0.6
-0.5
11.6
BNH008
40
68
15
1
0.6
-0.3
14.8
BNH009
BNH010
45
50
75
16
1
0.6
0
15.5
14.5
80
16
1
0.6
0.7
16.1
15.9
BNH011
BNH012
55
60
90
95
18
18
1.1
1.1
0.6
0.6
0.7
1.4
20.0
20.8
20.1
21.9
BNH013
BNH014
BNH015
BNH016
65
70
75
80
100
18
1.1
0.6
2.1
21.5
23.4
110
20
1.1
0.6
2.1
29.4
31.5
115
20
1.1
0.6
2.7
29.8
32.5
125
22
1.1
0.6
2.7
35.0
39.0
BNH017
BNH018
85
90
130
22
1.1
0.6
3.4
35.5
40.0
140
24
1.5
1
3.4
46.5
53.0
BNH019
95
145
24
1.5
1
4.1
47.0
55.0
BNH020
BNH021
BNH022
BNH024
BNH026
100
105
110
120
130
150
24
1.5
1
4.7
48.0
56.5
160
26
2
1
4.8
54.5
65.0
170
28
2
1
4.8
61.0
74.0
180
200
28
33
2
2
1
1
6.1
5.6
63.0
83.5
79.0
105
BNH028
BNH030
BNH032
140
150
160
210
33
2
1
6.9
86.0
112
225
35
2.1
1.1
7.6
102
132
240
38
2.1
1.1
7.8
110
145
BNH034
170
260
42
2.1
1.1
7.8
129
173
High-speed Angular Contact Ball Bearings
9.95
12.9
NACHI BEARING
R
R
R
R
d1
D2
R
D1
d1
d1
D1
D1
d1
d1
D2
Back-to-back
Rotation speed limit (rpm)
Grease lubrication
Oil lubrication
28900
26000
23400
21600
19400
18100
17000
15600
14800
13700
13100
12200
11700
11200
10600
10000
9400
8500
8000
7500
7000
6500
39000
35000
31500
29200
26200
24500
23000
21100
20000
18500
17700
16500
15800
15200
14300
13600
12700
11500
10900
10100
9500
8800
40
45
50
55
61
66
71
76
81
86
91
97
102
107
115
120
130
140
150
161
172
182
d1
Face-to-face
Corner radius (mm)
D1
(Min)
D2
Dimension Tables
Single-row or tandem
R1
D2
(Min)
d1
(Max)
R
(Max)
R1
(Max)
Mass
(kg)
(Reference)
Bearing no.
39
44
49.5
54.5
59.5
64.5
69.5
74.5
79.5
84.5
89.5
95.5
100.5
105.5
110.5
115.5
125.5
135.5
145.5
156
166
176
57
63
70
75
84
89
94
104
109
119
124
133
138
143
150
160
170
190
200
213
228
248
1
1
1
1
1
1
1
1
1
1
1
1.5
1.5
1.5
2
2
2
2
2
2
2
2
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
1
1
1
1
1
1
1
1
1
1
1
0.167
0.200
0.260
0.280
0.400
0.433
0.460
0.650
0.690
0.930
0.973
1.27
1.33
1.39
1.77
2.18
2.32
3.46
3.68
4.55
5.57
7.50
BNH007
BNH008
BNH009
BNH010
BNH011
BNH012
BNH013
BNH014
BNH015
BNH016
BNH017
BNH018
BNH019
BNH020
BNH021
BNH022
BNH024
BNH026
BNH028
BNH030
BNH032
BNH034
High-speed Angular Contact Ball Bearings
Types
and
Designs
7900
7000
7200
BNH
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
49
Thrust Load Angular Contact Ball Bearings
TAH/TBH Series
50
Thrust Load Angular Contact Ball Bearings
NACHI BEARING
Nomenclature of Bearing Numbers
Tolerance class code
P5 : JIS Class 5
P4 : JIS Class 4 (standard)
Dimension Tables
90 TBH 10 T DB /GM P4
Preload and other class codes
/GM : Medium preload (standard)
Mounting code
DB : Back-to-back (standard)
DF : Face-to-face
FFB : 3-row arrangement
Types
and
Designs
7900
7000
7200
Cage code
T : Phenolic resin cage
Dimension series number
10 : 10 Series
BNH
TAH
TBH
Bearing type
TAH : TAH Series Contact angle: 30°
TBH : TBH Series Contact angle: 40°
NN3000
NNU4900
XRN
XRG
Bore dimension (mm)
TAB
TAF
Features
Contact Angle
● Same number and diameter of balls as the TAD20 type doubledirection thrust angular contact ball bearings, and with smaller
contact angles, 30° (TAH Series) or 40° (TBH Series), providing
better high-speed performance with no separable ring.
● 2B width dimension of a duplex mounting (DB or DF) that is
equivalent to the B1 dimension of the TAD20 Type. TAH/TBH Series
are interchangeable by changing the method used to secure them
to the shaft.
2B
B
30° contact angle for the TAH Series, 40° contact angle for the TBH
Series.
Cage
Outer ring guided phenolic resin cage provided as standard.
Dimensional Accuracy, Rotational Accuracy
JIS Class 4 compliance as standard, but the external ring outside
diameter has smaller tolerances compared to the jointly used radial
bearing. See page 9 for details.
B
TAH (TBH) Type
Preload
Medium preload as standard. See page 19 for information about
preloads.
B1
TAD Type
Thrust Load Angular Contact Ball Bearings
51
Dimension Tables
Thrust Load Angular Contact Ball Bearings TAH Series
Contact angle 30°
2B
B
r1
B
r r
r1
r
r
ID
r1 r1
Id
30˚
a
1N=0.102kgf
Boundary dimensions (mm)
Bearing no.
52
d
D
2B
r
(Min)
r1
(Min)
Load center
a
(mm)
Basic dynamic
load rating
Ca
(kN)
Basic static load
rating
Coa
(kN)
50TAH10DB
50
80
28.5
1
0.6
11.6
19.2
40.5
55TAH10DB
60TAH10DB
55
60
90
33
1.1
0.6
12.7
23.8
51.0
95
33
1.1
0.6
14.1
24.7
56.0
65TAH10DB
65
100
33
1.1
0.6
15.6
25.6
61.0
70TAH10DB
75TAH10DB
80TAH10DB
85TAH10DB
90TAH10DB
95TAH10DB
70
75
80
85
90
95
110
115
36
36
1.1
1.1
0.6
0.6
17.0
18.4
35.0
35.5
80.0
83.5
125
40.5
1.1
0.6
19.5
41.5
99.5
130
40.5
1.1
0.6
20.9
42.0
104
140
45
1.5
1
21.9
55.5
135
145
45
1.5
1
23.4
56.0
141
100TAH10DB
100
150
45
1.5
1
24.8
57.0
147
105TAH10DB
105
160
49.5
2
1
25.9
64.5
168
110TAH10DB
120TAH10DB
110
120
170
54
2
1
26.9
73.0
191
180
54
2
1
29.8
75.0
207
130TAH10DB
140TAH10DB
150TAH10DB
160TAH10DB
130
140
150
160
200
63
2
1
31.9
99.5
269
210
63
2
1
34.8
103
291
225
240
67.5
72
2.1
2.1
1.1
1.1
37.3
39.7
121
131
340
375
170TAH10DB
170
260
81
2.1
1.1
41.8
154
445
Thrust Load Angular Contact Ball Bearings
NACHI BEARING
R1
R
Da da
da
Da
Dimension Tables
Rotation speed limit (rpm)
Grease
lubrication
11500
10300
9700
9100
8300
7900
7300
7000
6500
6200
6000
5600
5300
5000
4500
4200
4000
3700
3400
Corner radius (mm)
Oil lubrication
da
(Min)
Da
(Max)
R
(Min)
R1
(Min)
Mass
(kg)
(Reference)
Bearing no.
14600
13100
12300
11500
10600
10000
9200
8800
8200
7900
7600
7100
6800
6300
5700
5400
5000
4700
4400
61
68
73
78
85
90
97
102
107.5
112.5
117.5
125
132
142
156
166
178
190
204
75
84
89
94
104
109
118
123
132
137
142
151
160
170
188
198
212
227
245
1
1
1
1
1
1
1
1
1.5
1.5
1.5
2
2
2
2
2
2
2
2
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
1
1
1
1
1
1
1
1
1
1
1
0.266
0.405
0.432
0.460
0.622
0.655
0.900
0.944
1.24
1.30
1.35
1.75
2.20
2.36
3.52
3.75
4.59
5.62
7.63
50TAH10DB
55TAH10DB
60TAH10DB
65TAH10DB
70TAH10DB
75TAH10DB
80TAH10DB
85TAH10DB
90TAH10DB
95TAH10DB
100TAH10DB
105TAH10DB
110TAH10DB
120TAH10DB
130TAH10DB
140TAH10DB
150TAH10DB
160TAH10DB
170TAH10DB
Thrust Load Angular Contact Ball Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TAH
TBH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
53
Dimension Tables
Thrust Load Angular Contact Ball Bearings TBH Series
Contact angle 40°
2B
B
B
r1
r r
r1
r
r
ID
r1 r1
Id
40˚
a
Boundary dimensions (mm)
Bearing no.
54
d
D
2B
r
(Min)
1N=0.102kgf
r1
(Min)
Load center
a
(mm)
Basic dynamic
load rating
Ca
(kN)
Basic static load
rating
Coa
(kN)
50TBH10DB
50
80
28.5
1
0.6
20.2
22.8
53.0
55TBH10DB
55
90
33
1.1
0.6
22.2
28.2
67.0
60TBH10DB
65TBH10DB
60
65
95
33
1.1
0.6
24.3
29.3
73.0
100
33
1.1
0.6
26.4
30.0
70TBH10DB
75TBH10DB
70
75
110
115
36
36
1.1
1.1
0.6
0.6
28.8
30.9
41.5
42.0
104
109
80TBH10DB
85TBH10DB
90TBH10DB
95TBH10DB
80
85
90
95
125
40.5
1.1
0.6
32.9
49.0
130
130
40.5
1.1
0.6
35.0
50.0
136
140
45
1.5
1
37.0
65.5
176
145
45
1.5
1
39.1
66.5
184
100TBH10DB
105TBH10DB
100
105
150
45
1.5
1
41.2
67.5
191
160
49.5
2
1
43.2
76.5
219
110TBH10DB
110
170
54
2
1
45.3
86.0
249
120TBH10DB
130TBH10DB
140TBH10DB
150TBH10DB
160TBH10DB
120
130
140
150
160
180
54
2
1
49.5
88.5
200
63
2
1
53.5
118
350
210
225
63
67.5
2
2.1
1
1.1
57.7
61.8
121
143
380
445
240
72
2.1
1.1
65.9
155
490
170TBH10DB
170
260
81
2.1
1.1
70.0
182
580
Thrust Load Angular Contact Ball Bearings
79.5
269
NACHI BEARING
R1
R
Da da
da
Da
Dimension Tables
Rotation speed limit (rpm)
Grease
lubrication
10000
8900
8300
7900
7200
6800
6300
6000
5600
5400
5200
4900
4600
4300
3900
3700
3400
3200
3000
Corner radius (mm)
Oil lubrication
da
(Min)
Da
(Max)
R
(Min)
R1
(Min)
Mass
(kg)
(Reference)
Bearing no.
13200
11800
11000
10400
9500
9000
8300
7900
7400
7100
6800
6400
6100
5700
5200
4900
4500
4200
3900
61
68
73
78
85
90
97
102
107.5
112.5
117.5
125
132
142
156
166
178
190
204
75
84
89
94
104
109
118
123
132
137
142
151
160
170
188
198
212
227
245
1
1
1
1
1
1
1
1
1.5
1.5
1.5
2
2
2
2
2
2
2
2
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
1
1
1
1
1
1
1
1
1
1
1
0.266
0.405
0.432
0.460
0.622
0.655
0.900
0.944
1.24
1.30
1.35
1.75
2.20
2.36
3.52
3.75
4.59
5.62
7.63
50TBH10DB
55TBH10DB
60TBH10DB
65TBH10DB
70TBH10DB
75TBH10DB
80TBH10DB
85TBH10DB
90TBH10DB
95TBH10DB
100TBH10DB
105TBH10DB
110TBH10DB
120TBH10DB
130TBH10DB
140TBH10DB
150TBH10DB
160TBH10DB
170TBH10DB
Thrust Load Angular Contact Ball Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TAH
TBH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
55
Multiple-row Cylindrical Roller Bearings
NN3000 Series/
NNU4900 Series
56
Multiple-row Cylindrical Roller Bearings
NACHI BEARING
Nomenclature of Bearing Number
Tolerance class code
P5 : JIS Class 5
Inner clearance code P4 : JIS Class 4
C9NA : Non-interchangeable clearance (tapered bore)
C1NA : Non-interchangeable clearance (cylindrical bore, tapered bore)
C2NA : Non-interchangeable clearance (cylindrical bore, tapered bore)
CNA : Non-interchangeable clearance (cylindrical bore)
C3NA : Non-interchangeable clearance (cylindrical bore)
Bore shape code
(No code) : Cylindrical bore
K
: Tapered bore
Bearing type
NN : Multi-row cylindrical roller bearing (ribbed inner ring, non-ribbed outer ring)
NNU : Multi-row cylindrical roller bearing (non-ribbed inner ring, ribbed outer ring)
● Comparatively simple construction provides high accuracy. A large
number of rollers for high rigidity.
● Fewer sliding sections than a tapered rollar bearing so less heat is
generated.
● Tapered bore bearing allows adjusting of radial internal clearance
during assembly.
● This bearing cannot bear axial load, so normally it is used in
combination with a thrust bearing.
Cage
Both the NN3000 Series and NNU4900 Series are provided with
brass alloy roller guide cage as standard.
Dimensional Accuracy, Rotational Accuracy
● Conforms to JIS Class 5 or Class 4. See page 7 for details.
● Nachi defines its own tolerance values for accuracy of dimensions.
See page 11 for details.
Radial Internal Clearance
Outer Ring Oil Hole Dimensions
The table below shows the dimensions of the outer ring oil hole and
oil groove (W33 Specification).
Outer ring width dimension
B (mm)
Over
Incl.
−
19
19
25
25
35
35
50
50
80
−
80
Oil hole diameter
dH (mm)
Oil groove width
A (mm)
2
2
3
4
6
8
3.5
4
6
8
10
12
Nominal outside diameter dimensions
D (mm)
Over
Incl.
−
250
−
250
Types
and
Designs
7900
7000
7200
BNH
Oil hole number
Cage code
(No code) : Without outer ring oil groove, oil hole (No code) : Machined brass cage (integrated)
W33
: With outer ring oil groove and oil hole M2
: Machined brass cage (separate)
Bore diameter number
(bore dimension) = (bore number) ×5 mm
Dimension series number
49 : 49 Series
30 : 30 Series
Features
Dimension Tables
NN 30 06 W33 M2 K C1NA P4
Number of oil holes
N
4
6
A
N-dH
Nachi defines its own non-interchangeable clearances for cylindrical
bores and tapered bores in order to minimize axial run-out
inconsistency. See page 21 for details.
Multiple-row Cylindrical Roller Bearings
57
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
Dimension Tables
Multiple-row Cylindrical Roller Bearing NN3000 Series
B
r
r
Id
NN Type
Cylindrical bore
NN Type
With outer ring oil groove and oil hole
Tapered bore (1/12)
(W33)
Bearing no.
Cylindrical bore
58
Tapered bore
Id
1/12
Taper
IEW
ID
r
Boundary dimensions (mm)
d
D
B
Ew
r
(Min)
Basic dynamic
load rating
Cr
(kN)
Basic static load
rating
Cor
(kN)
NN3005
NN3005K
25
47
16
41.3
0.6
25.8
30.0
NN3006
NN3006K
30
55
19
48.5
1
31.0
37.0
NN3007
NN3008
NN3007K
NN3008K
35
40
62
20
55
1
39.5
50.0
68
21
61
1
43.5
55.5
NN3009
NN3010
NN3011
NN3012
NN3013
NN3014
NN3009K
NN3010K
NN3011K
NN3012K
NN3013K
NN3014K
45
50
55
60
65
70
75
23
67.5
1
52.0
65.5
80
90
23
26
72.5
81
1
1.1
53.0
69.5
72.5
96.5
95
26
86.1
1.1
73.5
106
100
26
91
1.1
77.0
116
110
30
100
1.1
97.5
148
NN3015
NN3016
NN3015K
NN3016K
75
80
115
30
105
1.1
96.5
149
125
34
113
1.1
119
186
NN3017
NN3017K
85
130
34
118
1.1
125
201
NN3018
NN3019
NN3020
NN3021
NN3018K
NN3019K
NN3020K
NN3021K
90
95
100
105
140
37
127
1.5
143
228
145
37
132
1.5
150
246
150
37
137
1.5
157
265
160
41
146
2
198
320
NN3022
NN3024
NN3026
NN3028
NN3022K
NN3024K
NN3026K
NN3028K
110
120
130
140
170
180
45
46
155
165
2
2
229
239
375
405
200
52
182
2
284
475
210
53
192
2
298
515
NN3030
NN3032
NN3034
NN3036
NN3038
NN3040
NN3030K
NN3032K
NN3034K
NN3036K
NN3038K
NN3040K
150
160
170
180
190
200
225
56
206
2.1
335
585
240
60
219
2.1
375
660
260
67
236
2.1
450
805
280
74
255
2.1
565
995
290
75
265
2.1
595
1080
310
82
282
2.1
655
1170
NN3044
NN3048
NN3044K
NN3048K
220
240
340
360
90
92
310
330
3
3
815
855
1480
1600
NN3052
NN3056
NN3052K
NN3056K
260
280
400
104
364
4
1080
2070
420
106
384
4
1080
2080
NN3060
NN3064
NN3060K
NN3064K
300
320
460
118
418
4
1430
2740
480
121
438
4
1430
2750
Multiple-row Cylindrical Roller Bearings
NACHI BEARING
Ida
IDa
Ida1
ra
Dimension Tables
Rotation speed limit (rpm)
Grease
lubrication
21300
18000
15800
14200
12800
11700
10500
9800
9200
8500
8000
7500
7100
6600
6300
6100
5800
5400
5100
4600
4300
4100
3800
3500
3300
3200
2900
2700
2500
2300
2100
2000
1900
Corner radius (mm)
Mass (kg)
(Reference)
(Tapered bore)
Bearing no.
(Tapered bore)
(Min)
ra
(Max)
41.8
49
56
62
69
74
82
87
92
101
106
114
119
129
134
139
148
157
167
183
194
208
221
238
257
267
285
313
333
367
387
421
442
0.6
1
1
1
1
1
1
1
1
1
1
1
1
1.5
1.5
1.5
2
2
2
2
2
2
2
2
2
2
2
2.5
2.5
3
3
3
3
0.123
0.199
0.258
0.312
0.405
0.454
0.651
0.704
0.758
1.04
1.14
1.52
1.61
2.07
2.17
2.26
2.89
3.68
3.98
5.92
6.44
7.81
8.92
12.6
16.6
17.5
21.6
28.4
31.8
46.0
49.6
68.7
74.0
NN3005K
NN3006K
NN3007K
NN3008K
NN3009K
NN3010K
NN3011K
NN3012K
NN3013K
NN3014K
NN3015K
NN3016K
NN3017K
NN3018K
NN3019K
NN3020K
NN3021K
NN3022K
NN3024K
NN3026K
NN3028K
NN3030K
NN3032K
NN3034K
NN3036K
NN3038K
NN3040K
NN3044K
NN3048K
NN3052K
NN3056K
NN3060K
NN3064K
Da
Oil lubrication
da
(Min)
da1
(Min)
(Max)
25000
21200
18600
16700
15000
13800
12400
11600
10900
10000
9400
8800
8300
7800
7500
7200
6800
6400
6000
5400
5100
4800
4500
4200
3900
3700
3500
3200
3000
2700
2500
2300
2200
30
36
41
46
51
56
62
67
72
77
82
87
92
98.5
103.5
108.5
115
120
130
140
150
162
172
182
192
202
212
234
254
278
298
318
338
30
37
42
48
52
58
64
68
74
78
84
90
96
100
106
112
116
122
132
144
154
164
174
184
196
206
216
238
256
280
300
325
345
42
49
56
62
69
74
83
88
93
103
108
118
123
131.5
136.5
141.5
150
160
170
190
200
213
228
248
268
278
298
326
346
382
402
442
462
Multiple-row Cylindrical Roller Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
59
Dimension Tables
Multiple-row Cylindrical Roller Bearing NNU4900 Series
B
r
r
NNU Type
Cylindrical bore
Bearing no.
Cylindrical bore
60
Tapered bore
1/12
Taper
Id
IFW
Id
ID
r
NNU Type
Tapered bore (1/12)
Ew
r
(Min)
Basic dynamic
load rating
Cr
(kN)
Boundary dimensions (mm)
d
D
B
Basic static load
rating
Cor
(kN)
NNU4920
NNU4920K
100
140
40
113
1.1
155
305
NNU4921
NNU4921K
105
145
40
118
1.1
161
325
NNU4922
NNU4924
NNU4922K
NNU4924K
110
120
150
40
123
1.1
167
335
165
45
134.5
1.1
183
360
NNU4926
NNU4928
NNU4926K
NNU4928K
130
140
180
190
50
50
146
156
1.5
1.5
275
283
565
585
NNU4930
NNU4932
NNU4934
NNU4936
NNU4930K
NNU4932K
NNU4934K
NNU4936K
150
160
170
180
210
60
168.5
2
350
715
220
60
178.5
2
365
760
230
60
188.5
2
375
805
250
69
202
2
480
1020
NNU4938
NNU4940
NNU4938K
NNU4940K
190
200
260
69
212
2
485
1060
280
80
225
2.1
570
1220
NNU4944
NNU4944K
220
300
80
245
2.1
600
1330
NNU4948
NNU4952
NNU4956
NNU4960
NNU4964
NNU4948K
NNU4952K
NNU4956K
NNU4960K
NNU4964K
240
260
280
300
320
320
80
265
2.1
625
1450
360
100
292
2.1
935
2100
380
420
100
118
312
339
2.1
3
960
1230
2230
2880
440
118
359
3
1270
3050
Multiple-row Cylindrical Roller Bearings
NACHI BEARING
Idc
Ida1
Ida
IDa
ra
Dimension Tables
Rotation speed limit (rpm)
Grease
lubrication
Oil lubrication
6300
6100
5800
5300
4900
4600
4200
4000
3800
3500
3400
3200
2900
2700
2400
2300
2100
2000
7500
7200
6900
6300
5800
5400
5000
4700
4500
4200
4000
3700
3400
3200
2900
2700
2500
2300
Corner radius (mm)
da
(Min)
(Max)
da1
(Min)
106.5
111.5
116.5
126.5
138
148
159
169
179
189
199
211
231
251
271
291
313
333
111
116
121
133
144
154
166
176
186
199
209
222
242
262
288
308
335
335
110
115
120
130
142
151
162
172
182
194
204
214
234
254
276
296
320
340
dc
(Min)
Da
(Max)
ra
(Max)
115
120
125
137
148
158
171
182
192
205
215
228
248
269
296
316
343
363
133.5
138.5
143.5
158.5
172
182
201
211
221
241
251
269
289
309
349
369
407
427
1
1
1
1
1.5
1.5
2
2
2
2
2
2
2
2
2
2
2.5
2.5
Mass (kg)
(Reference)
(Tapered bore)
Bearing no.
(Tapered bore)
1.77
1.85
1.93
2.65
3.55
3.80
5.95
6.25
6.60
9.50
10.0
10.1
15.5
17.0
28.3
30.3
46.7
49.6
NNU4920K
NNU4921K
NNU4922K
NNU4924K
NNU4926K
NNU4928K
NNU4930K
NNU4932K
NNU4934K
NNU4936K
NNU4938K
NNU4940K
NNU4944K
NNU4948K
NNU4952K
NNU4956K
NNU4960K
NNU4964K
Multiple-row Cylindrical Roller Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
61
Cross Tapered Roller Bearings
XRN Series/XRG Series
62
Cross Tapered Roller Bearings
NACHI BEARING
Nomenclature ofBearing Number
300 XRN 40
Outside diameter value
Outside diameter
divided by 10
Features
● A bearing that can stand up to radial loads, axial loads, and
moment loads.
● Bearing applications can be simplified, fewer components reduce
weight and size, reduced assembly time.
● Shaft thermal expansion has minimal affect on bearing preload
promoting machine accuracy.
● Tapered rollers are used and the center of rotation is maintained
for smooth rotation, even under preload.
● Polyamide resin spacers are inserted between rollers to minimize
roller-to-roller friction (except XRGV Type).
● Angle of contact is approximately 45°.
Bearing type
XRN : XRN Series Inner ring separable type
XRG : XRG Series Outer ring separable type
XRGV : XRG Series Outer ring separable type,
no spacer
Bore dimension (mm)
Axial Load and Axial Displacement
1
0.020
2
345
Axial displacement [mm]
Installation Example of Tapered Roller Bearing and Cross Tapered Roller Bearing
TAH
TBH
9
10
0.014
0.008
0.006
1 : 200XRN28
2 : 250XRN33 / 250XRN35
3 : 300XRN40 / 310XRN42
4 : 350XRN47
5 : 0330XRN045
6 : 375XRN49
0.002
0
10
20
30
40
50
60
Axial load [kN]
70
7 : 0457XRN060
8 : 400XRN55
9 : 580XRN76
10 : 0685XRN091
11 : 0901XRN112
12 : 950XRN117
80
90
100
XRG Series
XRG (XRGV) Type
Main Applications
● Work table of a machining center, grinding machine, etc.
● Work spindle of a lathe, grinding machine, etc.
● Large-scale milling machine, drilling machine, or other indexing
machine.
● Pivot of parabolic antenna, etc.
1 2
3
4
0.020
0.018
5
0.016
Axial displacement [mm]
The XRN Series is a separable inner ring, primary outer ring type
bearing, intended mainly for applications where the focus is on
outer ring accuracy under outer ring rotation. The XRG Series, on the
other hand mainly is used where the focus is on inner ring rotation
accuracy during inner ring rotation.
NN3000
NNU4900
XRN
XRG
TAB
TAF
0.010
Nachi defines its own accuracy standards. See page 9 for details.
XRN Type
11
12
0.012
0.004
Accuracy
Mechanism
7900
7000
7200
BNH
7 8
6
0.016
Cross Tapered Roller Bearings
Types
and
Designs
XRN Series
0.018
Duplex Tapered Roller Bearings
Dimension Tables
A bearing that provides functions equivalent to a duplex tapered
roller bearing, but in the size of a single bearing. The rolling
elements are arranged in alternating orientation between the
separable ring and the primary ring.
0.014
0.012
0.010
0.008
0.006
1 : 130XRG23 / 150XRG23
2 : 140XRGV20
3 : 200XRGV028
4 : 320XRG43
5 : 480XRGV66
0.004
0.002
0
10
20
30
40
50
60
Axial load [kN]
70
80
90
Cross Tapered Roller Bearings
100
63
Dimension Tables
Cross Tapered Roller Bearings XRN Series
Id
r
C
T
r
r
r
ID
Boundary dimensions (mm)
Bearing no.
150XRN23
64
d
D
T
C
r
Basic dynamic load
rating
Ca
(kN)
Basic static load
rating
Coa
(kN)
150
200
230
30
30
1.5
105
335
200XRN28
280
30
30
1.5
144
520
250XRN33
250
330
30
30
1
164
650
250XRN35
250
350
40
40
3
170
680
300XRN40
310XRN42
300
310
400
420
38
40
38
40
3
2.5
268
260
985
1070
0330XRN045
350XRN47
330.2
350
457.2
63.5
63.5
3.3
400
1540
470
50
50
3
284
1230
375XRN49
400XRN55
375
400
490
45
45
2.5
290
1280
550
60
60
3.5
365
1900
0457XRN060
580XRN76
0685XRN091
950XRN117
457.2
580
685.8
950
609.6
63.5
63.5
3.3
370
1670
760
80
80
6.4
830
3800
914.4
79.375
79.375
3.3
1090
5000
85
85
3
1440
7400
Cross Tapered Roller Bearings
1170
NACHI BEARING
Id1
ra
Dimension Tables
ra
ID1
Rotation speed limit (rpm)
Corner radius (mm)
Grease lubrication
Oil lubrication
d1
(Min)
600
480
400
400
330
320
290
280
260
250
220
170
140
100
1200
950
800
800
650
630
580
560
530
500
440
340
280
200
182
235
285
302
345
358
380
410
430
475
535
667
807
1050
D1
(Max)
ra
(Max)
Mass
(kg)
(Reference)
Bearing no.
197
249
298
312
369
380
409
424
445
492
554
691
834
1084
1
1
1
1.5
2.5
2
2
1.5
1.5
1.5
2
4
2
2.5
5.11
6.43
7.77
13.6
14.8
18.1
35.4
27.7
25.5
48.8
57.1
108
161
218
150XRN23
200XRN28
250XRN33
250XRN35
300XRN40
310XRN42
0330XRN045
350XRN47
375XRN49
400XRN55
0457XRN060
580XRN76
0685XRN091
950XRN117
Cross Tapered Roller Bearings
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRN
XRG
TAB
TAF
65
Dimension Tables
Cross Tapered Roller Bearings XRG Series
Id
r
T
B
r
r
r
ID
Boundary dimensions (mm)
Bearing no.
66
D
T
130
140
230
30
30
1.5
105
335
140XRGV20
200
25
25
1.5
89
299
150XRG23
200XRGV028
150
200
230
285
30
30
30
30
1.5
1
105
170
335
655
320XRG43
480XRGV66
320
480
430
40
40
2.5
260
1070
660
50
49.5
4
405
2110
Cross Tapered Roller Bearings
r
Basic static load
rating
Coa
(kN)
d
130XRG23
B
Basic dynamic load
rating
Ca
(kN)
NACHI BEARING
Id1
ra
Dimension Tables
ra
ID1
Rotation speed limit (rpm)
Corner radius (mm)
Grease lubrication
Oil lubrication
d1
(Min)
650
680
600
480
300
200
1250
1350
1200
950
600
400
182
162
182
235
358
550
D1
(Max)
ra
(Max)
Mass
(kg)
(Reference)
Bearing no.
197
176
197
249
382
572
1
1
1
1
2
3
5.97
2.86
5.11
7.13
18.9
61.0
130XRG23
140XRGV20
150XRG23
200XRGV028
320XRG43
480XRGV66
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRN
XRG
TAB
TAF
Cross Tapered Roller Bearings
67
Ball Screw Support Bearings
TAB/TAF Series
TAB Series
Ball screw support bearings are used in high accuracy and high-speed precision machine tools,
precision measuring machines, robots, and other machines that have built in precision feed actuators.
Nomenclature of Bearing Numbers
30 TAB 06 DB -2LR /GM P4
Tolerance class code
Preload and other class codes P4 : JIS Class 4 (standard)
/GM : Medium preload (standard)
Seal code
(No code) : Open type
-2LR
: With two contact seals
-2NK
: With two non-contact seals
Features
● Resin cage and more balls than previous ball bearings for greater
rigidity.
● Combination bearings are provided with preset preloads,
eliminating the need for troublesome installation adjustment using
shims and torque measurements.
● A contact angle of 60° and has the ability to handle radial and
axial loads creates a compact bearing.
● The seal type provides a choice between contact seal and noncontact seal to suit specific applications.
Contact Angle
The contact angle is 60°.
Cage
A ball guided polyamide resin cage is provided as standard.
Preload
Medium preload as standard. See page 20 for details.
Axial Load and Axial Displacement
30
Fa
1
2
Axial elastic displacement [μm]
Bearing type
Bore dimension (mm)
Mounting code
U : Flush ground (single)
DU : Flush ground (duplex)
DB : Back-to-back
DF : Face-to-face
Outside diameter value
Outside diameter divided by 10
3
4
5
6
7
8
20
10
Bearing (single)
1 : 15, 17, 20TAB04
2 : 25, 30TAB06
3 : 40TAB09
4 : 35, 40TAB07
5 : 45TAB10
6 : 45TAB07
7 : 50, 55TAB10
8 : 55, 60TAB12
Accuracy
JIS Class 4 is standard. See page 10 for details.
0
0
4000
8000
Axial load Fa [N]
68
Ball Screw Support Bearings
12000
NACHI BEARING
Nomenclature of Bearing Numbers
25 TAF 06 DF /GM P5
Tolerance class code
Preload and other class codes P5 : JIS Class 5 (standard)
/GM : Medium preload (standard)
Mounting code
DB : Back-to-back
DF : Face-to-face
DT : Tandem
Bearing type
Bore dimension (mm)
Dimension Tables
Though hydraulic actuators were widely used in the past in high load drive devices like injection molding
machines, the use of electric drives (ball screw drives) in such applications is becoming more common. The
TAF Series are special bearings designed to support high-load drive ball screws.
TAF Series
Types
and
Designs
7900
7000
7200
BNH
Outside diameter value
Outside diameter divided by 10 (with some exceptions)
TAH
TBH
NN3000
NNU4900
Features
Preload
● A large-diameter ball and large contact angle provides the high
thrust load capacity needed for the high loads of the ball screw
used in injection molding machines.
● A one-piece molded cage that combines both greater accuracy
and strength, and the ability to withstand repeated high-speed
switching between forward and reverse.
XRN
XRG
Medium preload as standard. See page 20 for details.
TAB
TAF
Cage
A ball guide polyamide resin cage is provided as standard. Some
sizes come with a machined brass cage.
Contact Angle
A contact angle of 50° up to a nominal bore of 80 mm, and 55° for a
nominal bore of 100 mm or greater.
Accuracy
JIS Class 5 is standard. See page 11 for details.
Comparison of Basic Dynamic Axial Loads
Comparison of Axial Limiting Loads
250
450
TAF Series
73B Series
TAB Series
400
TAF Series
73B Series
TAB Series
200
350
300
150
250
200
100
150
100
50
50
0
I25
I30
I35
I40
I50
Bore dimension (mm)
I60
I80
I100
0
I25
I30
I35
I40
I50
Bore dimension (mm)
I60
I80
I100
Ball Screw Support Bearings
69
Dimension Tables
Ball Screw Support Bearing TAB Series
B
r
r1
60°
Open type
IDa2
Ida1
Ida2
IDa1
IDa2
Id
Ida1
r
Ida2
IDa1
ID
r
Contact seal (2LR)
Non-contact seal (2NK)
Boundary dimensions (mm)
Bearing no.
15TAB04
15TAB04-2NK
d
D
B
r
(Min)
r1
(Min)
15
15
47
15
1(1)
0.6
25.9
32.0
47
15
1(1)
0.6
25.9
32.0
(1)
15TAB04-2LR
17TAB04
15
17
47
15
1
0.6
25.9
32.0
47
15
1
0.6
25.9
32.0
17TAB04-2NK
17TAB04-2LR
20TAB04
20TAB04-2NK
20TAB04-2LR
25TAB06
17
17
20
20
20
25
47
15
1
0.6
25.9
32.0
47
47
15
15
1
1
0.6
0.6
25.9
25.9
32.0
32.0
47
15
1
0.6
25.9
32.0
47
15
1
0.6
25.9
32.0
62
15
1
0.6
29.9
46.4
25TAB06-2NK
25TAB06-2LR
25
25
62
15
1
0.6
29.9
46.4
62
15
1
0.6
29.9
46.4
30TAB06
30
62
15
1
0.6
29.9
46.4
30TAB06-2NK
30TAB06-2LR
35TAB07
35TAB07-2NK
30
30
35
35
62
15
1
0.6
29.9
46.4
62
15
1
0.6
29.9
46.4
72
15
1
0.6
32.5
54.3
72
15
1
0.6
32.5
54.3
35TAB07-2LR
40TAB07
40TAB07-2NK
40TAB07-2LR
35
40
40
40
72
72
15
15
1
1
0.6
0.6
32.5
32.5
54.3
54.3
72
15
1
0.6
32.5
54.3
72
15
1
0.6
32.5
40TAB09
40TAB09-2NK
40TAB09-2LR
45TAB07
45TAB10
50TAB10
40
40
40
45
45
50
90
20
1
0.6
65.0
101
90
20
1
0.6
65.0
101
90
20
1
0.6
65.0
101
75
15
1
0.6
33.5
100
20
1
0.6
68.0
113
100
20
1
0.6
69.5
119
55TAB10
55TAB12
55
55
100
120
20
20
1
1
0.6
0.6
69.5
73.0
119
137
60TAB12
60
120
20
1
0.6
73.0
137
Note (1) Minimum r for inner ring bore is 0.6.
(2) When the axial load is on a 2-row or 3-row arrangement, the values in the table should be multiplied by 1.62 and 2.16 respectively.
(3) When the axial load is on a 2-row or 3-row arrangement, the values in the table should be multiplied by 2 and 3 respectively.
(4) Rotation speed limit for medium preload (preload code GM).
70
Basic dynamic load
rating (2)
Axial limiting load (3)
Ca
(kN)
(kN)
Ball Screw Support Bearings
54.3
59.5
NACHI BEARING
Dynamic equivalent axial load Pa=X Fr+Y Fa
No. of bearings in set
2
Number of rows receiving axial load
Fa/Fr > 2.17
1 row
2 rows
1 row
2 rows
3 rows
1 row
2 rows
3 rows
4 rows
X
1.90
−
1.43
2.33
−
1.17
2.33
2.53
−
Y
X
0.54
−
0.77
0.35
−
0.89
0.35
0.26
−
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
Y
1
1
1
1
1
1
1
1
1
Rotation speed limit (4) (rpm)
Grease
lubrication
4
Reference dimensions (mm)
Mass
(kg)
(Reference)
Dimension Tables
Fa/Fr ≤ 2.17
3
Bearing no.
Oil lubrication
da1
da2
Da1
Da2
6300
6300
8000
33.7
26.8
33.5
41
0.14
15TAB04
−
33.7
26.8
35
41.9
0.14
15TAB04-2NK
6300
−
8000
33.7
33.7
26.8
26.8
35
33.5
41.9
41
0.14
0.13
15TAB04-2LR
17TAB04
−
33.7
26.8
35
41.9
0.13
17TAB04-2NK
−
8000
−
33.7
33.7
33.7
26.8
26.8
26.8
35
33.5
35
41.9
41
41.9
0.13
0.12
0.12
17TAB04-2LR
20TAB04
20TAB04-2NK
−
6000
33.7
46.2
26.8
39.7
35
46
41.9
53.4
0.12
0.24
20TAB04-2LR
25TAB06
−
46.2
39.7
47.5
54.9
0.24
25TAB06-2NK
−
6000
46.2
46.2
39.7
39.7
47.5
46
54.9
53.4
0.24
0.21
25TAB06-2LR
30TAB06
−
46.2
39.7
47.5
54.9
0.21
30TAB06-2NK
−
5000
46.2
56.2
39.7
49.7
47.5
56
54.9
63.4
0.21
0.29
30TAB06-2LR
35TAB07
−
56.2
49.7
57.5
64.9
0.29
35TAB07-2NK
−
5000
−
56.2
56.2
56.2
49.7
49.7
49.7
57.5
56
57.5
64.9
63.4
64.9
0.29
0.26
0.26
35TAB07-2LR
40TAB07
40TAB07-2NK
−
4000
56.2
67.2
49.7
57.2
57.5
67
64.9
78.4
0.26
0.62
40TAB07-2LR
40TAB09
−
67.2
57.2
68.5
79.9
0.62
40TAB09-2NK
−
4500
3500
3500
3500
3000
3000
67.2
61.7
74.2
78.2
78.2
92.2
92.2
57.2
55.2
64.2
68.2
68.2
82.2
82.2
68.5
61.5
74
78
78
92
92
79.9
68.9
85.4
89.4
89.4
103.4
103.4
0.62
0.25
0.79
0.72
0.95
1.15
1.08
40TAB09-2LR
45TAB07
45TAB10
50TAB10
55TAB10
55TAB12
60TAB12
6300
6300
6300
6300
6300
6300
4650
4650
4650
4650
4650
4650
3750
3750
3750
3750
3750
3750
3150
3150
3150
3400
2850
2700
2700
2300
2300
Ball Screw Support Bearings
Types
and
Designs
71
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
Dimension Tables
Ball Screw Support Bearing TAF Series
B
Id
Ida1
r
Ida2
IDa1
ID
D
r1
IDa2
r1
r
Contact angle
D (°)
Basic dynamic
load rating (1)
Ca
(kN)
Axial limiting
load (2)
(kN)
Boundary dimensions (mm)
Bearing no.
d
D
B
r
(Min)
r1
(Min)
25TAF06
30TAF07
25
30
62
17
1.1
0.6
50
56.0
47.5
72
19
1.1
0.6
50
74.0
58.0
35TAF09
40TAF09
35
40
90
23
1.5
1
50
103
90
23
1.5
1
50
103
40TAF11
45TAF11
40
45
110
110
27
27
2
2
1
1
50
50
152
152
118
118
50TAF11
60TAF13
60TAF17
80TAF17
50
60
60
80
110
27
2
1
50
152
118
130
31
2.1
1.1
50
196
157
170
39
2.1
1.1
50
279
238
170
39
2.1
1.1
50
279
238
100TAF21
120TAF03
100
120
215
47
3
1.1
55
385
234
260
55
3
1.1
55
445
380
Note (1) When the axial load is on a 2-row or 3-row arrangement, the values in the table should be multiplied by 1.62 and 2.16 respectively.
(2) When the axial load is on a 2-row or 3-row arrangement, the values in the table should be multiplied by 2 and 3 respectively.
(3) Use at 80% or less of the allowable axial load is recommended.
(4) Rotation speed limit for medium preload (preload code GM).
72
Ball Screw Support Bearings
77.0
77.0
NACHI BEARING
Dynamic equivalent axial load Pa=X Fr+Y Fa
Contact angle 50°
Contact angle 55°
No. of bearings in set
2
Number of rows receiving axial load
Fa/Fr ≤ 1.49
Fa/Fr > 1.49
2 rows
1.37
−
0.57
−
0.73
0.73
1
1
2
Number of rows receiving axial load
Fa/Fr ≤ 1.79
Fa/Fr > 1.79
Reference dimensions (mm)
Rotation speed limit (4)
(rpm)
Grease lubrication
da1
da2
Da1
4500
3800
3000
3000
2500
2500
2500
2100
1500
1500
1200
1000
42.9
49.8
63.2
63.2
77.6
77.6
77.6
92.4
121.1
121.1
152.3
186.2
32.7
38.6
49.7
49.7
60.3
60.3
60.3
72.9
97.2
97.2
123.4
151.1
44.9
53
67.7
67.7
83.4
83.4
83.4
98.9
130.3
130.3
164.1
193.8
X
Y
X
Y
1 row
2 rows
1.60
−
0.56
−
0.81
0.81
1
1
Da2
Mass
(kg)
(Reference)
Bearing no.
56.6
65.9
82.3
82.3
101.1
101.1
101.1
119.7
155.8
155.8
194.7
228.4
0.237
0.357
0.709
0.655
1.28
1.21
1.13
1.79
4.48
3.80
7.41
14.8
25TAF06
30TAF07
35TAF09
40TAF09
40TAF11
45TAF11
50TAF11
60TAF13
60TAF17
80TAF17
100TAF21
120TAF03
Ball Screw Support Bearings
Dimension Tables
X
Y
X
Y
No. of bearings in set
1 row
Types
and
Designs
7900
7000
7200
BNH
TAH
TBH
NN3000
NNU4900
XRN
XRG
TAB
TAF
73
The appearance and specifications may be changed without prior notice if required to
improve performance.
Every care has been taken to ensure the accuracy of the information contained in this
catalog but no liability can be accepted for any errors or omissions.
CATALOG NO.
B1031E-5
2013.05.X-ABE-ABE

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