Super-precision cylindrical roller bearings: High

Super-precision cylindrical roller bearings: High
Super-precision
cylindrical roller
bearings: High-speed
N 10 series
Contents
A Product information
C Product data
High-speed super-precision single row
cylindrical roller bearings . . . . . . . . . . 3
The assortment. . . . . . . . . . . . . . . . . . . 4
High-speed design. . . . . . . . . . . . . . . . . 5
Preparing for oil injection . . . . . . . . . . 9
Bearing data – general. . . . . . . . . . . . .
Boundary dimensions . . . . . . . . . . . . . .
Chamfer dimensions. . . . . . . . . . . . . . .
Tolerances . . . . . . . . . . . . . . . . . . . . . . .
Radial internal clearance . . . . . . . . . . . .
Axial displacement. . . . . . . . . . . . . . . . .
Radial stiffness. . . . . . . . . . . . . . . . . . . .
Equivalent loads. . . . . . . . . . . . . . . . . . .
Attainable speeds. . . . . . . . . . . . . . . . . .
Cage material. . . . . . . . . . . . . . . . . . . . .
Materials and heat treatment. . . . . . . . .
Packaging. . . . . . . . . . . . . . . . . . . . . . . .
Designation system . . . . . . . . . . . . . . . .
Application examples. . . . . . . . . . . . . . 10
Product table . . . . . . . . . . . . . . . . . . . . 18
Lubrication. . . . . . . . . . . . . . . . . . . . . . 12
Grease lubrication . . . . . . . . . . . . . . . . . 12
Oil lubrication. . . . . . . . . . . . . . . . . . . . . 13
D Additional information
Applications . . . . . . . . . . . . . . . . . . . . . 6
B Recommendations
Adjusting for clearance or preload . . . 8
Setting the highest standard for
precision bearings . . . . . . . . . . . . . . . .
Super-precision angular contact ball
bearings. . . . . . . . . . . . . . . . . . . . . . . . .
Super-precision cylindrical roller
bearings. . . . . . . . . . . . . . . . . . . . . . . . .
Super-precision double direction
angular contact thrust ball bearings. . . .
Super-precision angular contact thrust
ball bearings for screw drives. . . . . . . . .
Super-precision axial-radial cylindrical
roller bearings . . . . . . . . . . . . . . . . . . . .
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SKF – the knowledge engineering
company. . . . . . . . . . . . . . . . . . . . . . . . 22
2
High-speed super-precision single
row cylindrical roller bearings
Machine tools and other precision applications require superior bearing performance.
In these applications, a high degree of system rigidity is one of the main performance
challenges, as the magnitude of elastic
deform­ation under load determines the
product­ivity and accuracy of the equipment.
Another performance challenge is keeping
the amount of friction and heat generated
by the bearing to a minimum during highspeed operation.
To meet these demanding performance
criteria, N 10 series cylindrical roller bearings have an optimized internal geometry
and a redesigned cage, enabling them to
­accommodate a speed increase of up to 30%.
The bearings are characterized by:
• high-speed capability
• high load carrying capacity
• high stiffness
• low friction
• low cross sectional height
A
The non-locating bearing position is typically at the non-tool end of a spindle. If the
bearing at this position has a loose fit, it can
have a negative influence on the total rigidity of the bearing arrangement. Therefore,
for a high degree of stiffness at the non-tool
end of a spindle, N 10 series cylindrical roller bearings with a tapered bore should be
used. They accommodate axial displacement
within the bearing and enable an interference fit for both the inner and outer rings.
Bearings in the N 10 series provide high
reliability and superior accuracy for applications such as high-speed milling machines,
machining centres and lathes.
3
The assortment
SKF bearings in the N 10 series can accommodate shaft diameters ranging from 40 to
80 mm. The bearings are available with a
tapered bore only and are manufactured
to two tolerance classes. To accommodate
increased operational speeds, the bearings
are available in a hybrid variant.
The bearing overall dimensions are in
accordance with ISO Dimension Series 10
and have a low cross sectional height. They
are able to accommodate relatively large
diameter shafts to provide the necessary
system rigidity within a relatively small
bearing envelope. When compared to a set
of angular contact ball bearings with the same
load carrying capacity and the same degree
of rigidity, an N 10 series bearing requires
a much smaller radial space. This enables
compact spindle bearing arrangements.
Hybrid variant
Bearings in the N 10 series are available
with ceramic (bearing grade silicon nitride)
rollers. As ceramic rollers are considerably
lighter and harder than steel rollers, hybrid
bearings can provide a higher degree of rigidity and run considerably faster than comparably sized all-steel bearings. The lower
weight of the ceramic rollers reduces the
centrifugal forces within the bearing and
generates less heat. Lower centrifugal forces
are particularly important in machine tool
applications where there are frequent rapid
starts and stops. Less heat generated by the
bearing means less energy consumption
and longer bearing and grease service life.
Hybrid bearings in the N 10 series are
identified by the designation suffix HC5.
The bearings are available in an all-steel and
hybrid variant.
Steel rollers
Ceramic rollers
SKF super-precision single row cylindrical roller bearings: N 10 series
Features and benefits
• An inner ring with two integral flanges for roller guidance provides high load carrying capacity, high degree of rigidity.
• The improved internal geometry of the inner ring enables high-speed capability.
• An optimized PEEK cage accommodates high speeds and temperatures up to 150 °C.
• The optimized roller profile (hybrid bearings) enables high speeds, low levels of heat generation.
• ISO Dimension Series 10 enables compact bearing arrangements.
• The separable design facilitates mounting and dismounting.
• A tapered bore enables preload or clearance adjustments.
• A flangeless outer ring accommodates axial displacement, within the bearing, due to spindle elongation, and also enables an interference fit for both the inner and outer rings.
4
High-speed design
Super-precision single row cylindrical roller
bearings in the N 10 series are designed for
bearing arrangements requiring increased
speed capability, high load carrying capacity
and a high degree of radial stiffness.
The features of high-speed N 10 series
bearings include, among others, an optimized internal geometry, a flangesless outer
ring and a high-speed cage.
The bearings are separable, making it
possible to separate the inner ring with roller and cage assembly from the outer ring to
facilitate mounting and dismounting.
Optimized, high-speed cage
N 10 series bearings are equipped with an
outer ring centred, window-type cage made
of carbon fibre reinforced polyetherether­
ketone (PEEK). The symmetrical, self-­
centring design enables the cage to be better guided on the raceway of the outer ring,
compared to previous designs. The cage also
offers excellent guidance for the rollers and
provides access for the lubricant (typically
oil-air) to reach the contact areas between
the cage and the inner ring flanges. The exceptional properties of PEEK provide a
superior combination of strength and flexi­
bility at high operational speeds. PEEK can
also accommodate high operating temperatures while providing high wear resistance.
Compared to previous high-speed design
bearings, the new, optimized cage can accommodate a speed increase of up to 30% in
grease lubricated applications and up to 15%
in oil-air lubricated applications.
High-speed design cylindrical roller bearing
Comparison of attainable speeds – oil-air lubrication
Bearing type
Bearing series
SKF super-precision single row cylindrical roller
bearings
N 10 KPHA/HC5SP
SKF high-precision single row cylindrical roller
bearings
N 10 KTNHA/HC5SP
N 10 KPHA/SP
N 10 KTNHA/SP
N 10 KTN/HC5SP
N 10 KTN/SP
0
0,5
1,0
Comparison of attainable speeds – grease lubrication
Bearing type
Bearing series
SKF super-precision single row cylindrical roller
bearings
N 10 KPHA/HC5SP
SKF high-precision single row cylindrical roller
bearings
N 10 KTNHA/HC5SP
1,5
Speed
2,0
2,5
factor A [106 mm/min]
N 10 KPHA/SP
N 10 KTNHA/SP
N 10 KTN/HC5SP
N 10 KTN/SP
0
0,5
1,0
1,5
2,0
2,5
Speed factor A [106 mm/min]
5
A
Applications
In applications requiring a high degree of
system rigidity, cylindrical roller bearings are
typically an excellent choice.
The SKF assortment of super-­precision
single row cylindrical roller bearings in the
N 10 series is very well suited to meet this
requirement as well as other demands
placed on precision bearing arrangements.
High-speed milling machines and
­machining centres require high positioning
accuracy and low levels of heat generation.
In addition, these applications are often
subjected to heavy radial loads at the nontool end of the spindle. The ability of bearApplications
• Machine tools
• High-speed milling machines
• High-speed machining centres
• Lathe electro-spindles
ings in the N 10 series to accommodate
heavy loads at high speeds, and still provide
a high degree of radial stiffness, makes
them an excellent solution for these and
similar applications.
Requirements
• High-speed capability
• High load carrying capacity
• High degree of system rigidity
• High positioning accuracy
• Long service life
• Low friction
• Increased machine uptime
Solution
SKF high-speed super-precision single row
cylindrical roller bearings in the N 10 series
6
A
7
Adjusting for clearance or preload
When adjusting a cylindrical roller bearing
with a tapered bore for clearance or preload,
the result is determined by how far the
bearing is driven up on the tapered shaft
seat. The further the bearing is driven up
the seat, the more the clearance is reduced,
until eventually, there is preload in the bearing. To quickly and accurately determine the
amount of clearance or preload in the
mounted bearing, SKF recommends using a
GB 30 series internal clearance gauge
(† fig. 1).
If SKF gauges are not available, the axial
displacement, i.e. the additional distance
through which the bearing inner ring must
be pushed up on its tapered seat, can be
calculated. For additional information, refer
to the SKF Interactive Engineering Catalogue
available online at www.skf.com.
8
Fig. 1
Preparing for oil injection
B
For bearings in the N 10 series, particularly
the larger sizes, SKF recommends using the
SKF oil injection method to facilitate mounting and dismounting. With this method, oil
­under high pressure is injected between the
bearing inner ring bore and the shaft seat to
form an oil film that separates the mating
surfaces and appreciably reduces the friction between them. The distribution of oil
between the mating surfaces is accomplished by a circumferential oil distribution
groove in the shaft that communicates with
a supply duct in the shaft († fig. 1).
It is necessary to make provision for the
SKF oil injection method. This is usually
done at the design stage of the bearing
­arrangement. For additional information
about the SKF oil injection method and
­recommended dimensions for distribution
grooves and oil supply ducts, refer to the
SKF Interactive Engineering Catalogue
­available online at www.skf.com.
Fig. 1
9
Application examples
High-speed super-precision single row
­cylindrical roller bearings are common in,
but not limited to, machine tool applications.
Depending on the type of machine tool and
its intended purpose, spindles may require
different bearing arrangements.
For high-speed machining centres and
lathes, for example, there is typically a compromise between rigidity and load carrying
capacity. In these applications, the spindle is
often driven directly by a motor. The spindle
is then referred to as a motorized spindle or
electro-spindle. As there are only very light
radial loads at the non-tool end (compared
with a belt-driven spindle), but a high degree of rigidity is required, a super-precision
single row cylindrical roller bearing is frequently used at that end. A cylindrical roller
bearing at the non-tool end accommodates
thermal elongation of the shaft within the
bearing. Angular contact ball bearings at the
tool end locate the shaft axially.
High-speed milling machine
For high-speed milling machines, where a high degree of system rigidity is required, a super-precision single row cylindrical roller bearing at the non-tool end,
e.g. N 1013 KPHA/SP, is suitable. A matched set of four super-precision hybrid angular contact ball bearings, e.g. 7014 ACD/HCP4AQBCB, incorporating a set of
­precision-matched spacer rings, can be used at the tool end, providing an overall robust bearing arrangement.
10
B
High-speed milling machine
In a high-speed milling machine where there are relatively heavy combined loads at the tool end, a high degree of rigidity and high load carrying capacity are
important operational requirements. It is common to have a super-precision hybrid single row cylindrical roller bearing, e.g. N 1014 KPHA/HC5SP, in combination with a matched set of back-to-back super-precision hybrid angular contact ball bearings, e.g. 7014 ACD/HCP4ADBB, at the tool end. A super-precision
hybrid single row cylindrical roller bearing, e.g. N 1013 KPHA/HC5SP, is suitable for the non-tool end.
Electro-spindle for a high-speed machining centre
For high-speed machining centres where speeds can exceed 1 200 000 mm/min, a super-precision cylindrical roller bearing, e.g. N 1009 KPHA/SP, is used at
the non-tool end. A matched set of super-precision angular contact ball bearings mounted back-to-back, e.g. 7012 CD/P4ADBB, are used at the tool end.
11
Lubrication
Heat resulting from friction is a constant
threat to production equipment. One way to
reduce heat and the wear associated with
friction, particularly in bearings, is to be sure
that the correct quantity of the appropriate
lubricant reaches all necessary parts.
Initial grease fill
In high-speed applications, less than 30% of
the free space in the bearings should be
filled with grease. The initial grease fill depends on the bearing size as well as the
speed factor, which is
A = n dm
Grease lubrication
In most applications with bearings in the
N 10 series, grease with a mineral base oil
and lithium thickener is suitable. These
greases, which adhere well to the bearing
surfaces, can accommodate operating temperatures ranging from –30 to +100 °C.
where
A = speed factor [mm/min]
n = rotational speed [r/min]
dm= bearing mean diameter
= 0,5 (d + D) [mm]
The initial grease fill can be estimated by
Running-in of grease
lubricated bearings
A grease lubricated super-precision bearing
will initially run with a relatively high frictional moment. If the bearing is run at high
speed without a running-in period, the temperature rise can be considerable. The time
required to stabilize the operating temperature depends on a number of factors – the
type of grease, the initial grease fill, how the
grease is applied to the bearings and the
running-in procedure.
For additional information about runningin of grease lubricated bearings, refer to the
SKF Interactive Engineering Catalogue
­available online at www.skf.com.
G = K Gref
where
G = initial grease fill [cm3]
K = a calculation factor dependent on the
speed factor A († diagram 1)
Gref= reference grease quantity († table 1)
[cm3]
Diagram 1
Factor K for initial grease fill estimation
Reference grease quantity for initial grease
fill estimation
Factor K
Bearing
Bore
diameter
d
1,1
1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
12
Table 1
0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
Speed factor A [106 mm/min]
Size
Reference grease
quantity1)
Gref
mm
–
cm3
40
45
50
55
60
08
09
10
11
12
3,1
4,1
4,4
6,1
6,5
65
70
75
80
13
14
15
16
6,9
9,2
9,6
12,5
1) Refers
to a 30% filling grade.
Oil lubrication
Oil-air lubrication method
Where speeds are constantly very high
(generally, speed factor A > 1 800 000
mm/min), bearings in the N 10 series
should be oil lubricated, as the service life of
grease is too short under these conditions
and oil provides the added benefit of cooling.
In some precision applications, the very high
operational speeds and requisite low operating temperatures require an oil-air lubrication system. Oil is supplied to the feed
lines at given intervals by a metering unit.
The oil coats the inside surface of the feed
lines and “creeps” toward the nozzles
(† fig. 1), where it is delivered to the bearings. The oil nozzles should be positioned
correctly († table 2) to make sure that the
oil is introduced into the contact area between the rollers and raceways and to avoid
interference with the cage.
Guidelines for the oil quantity to be supplied to each bearing for very high speed
operation can be obtained from
B
qdB
Q = –––––
100
where
Q= oil flow rate [mm3/h]
d = bearing bore diameter [mm]
B= bearing width [mm]
q = a factor of 1 to 2
Different bearing types and designs show
varying sensitivity to oil quantity change.
Roller bearings, which are very sensitive to
lubricant quantity, can experience a significant increase in operating temperature.
Therefore, SKF recommends testing and
verifying the calculated oil flow rate prior to
operation in a production environment.
High quality lubricating oils with a viscosity of 40 to 100 mm2/s at 40 °C are typically
used, as are oils with EP additives, which are
preferable for roller bearings. A filter that
prevents particles > 5 μm from reaching the
bearings should also be incorporated.
Fig. 1
Mixing valve
0,5 to 10 m
Helical coil
Oil + air line
Nozzle
Table 2
Oil nozzle position for oil-air lubrication
d dn
Bearing
Bore
diameter
d
Size
Oil nozzle
position
dn
mm
–
mm
40
45
50
55
60
08
09
10
11
12
52,1
57,9
63
70,1
75,2
65
70
75
80
13
14
15
16
80,1
87,7
92,7
99,3
13
Bearing data – general
Boundary dimensions
The boundary dimensions of bearings in the
N 10 series are in accordance with ISO
15:2011, Dimension Series 10.
Chamfer dimensions
Minimum values for the chamfer dimensions
in the radial direction (r1, r3) and the axial
direction (r2, r4) are provided in the product
table. The values for the chamfers on the
outer ring are in accordance with
ISO 15:2011. The values for the chamfers
on the inner ring are smaller and are not
standardized.
The appropriate maximum chamfer ­limits
are in accordance with ISO 582:1995.
Radial internal
clearance
Bearings in the N 10 series are manufactured, standard, with C1 radial internal
clearance. On request, the bearings can be
supplied with a special reduced radial internal clearance (smaller than C1), when a
Table 1
Class SP tolerances
Inner ring
d
over
incl.
Δds1)
high
mm
µm
30
50
50
80
µm
µm
0
0
low
VDp
max
ΔCs, VCs
Bearings in the N 10 series are manufactured, standard, to an SP (special precision)
tolerance class († table 1), which is approximately in accordance with ISO tolerance class 5 for dimensional accuracy and
approximately in accordance with ISO tolerance class 4 for running accuracy.
On request, bearings can be supplied in
an ultra-precision (UP) tolerance class
(† table 2), which is approximately in accordance with ISO tolerance class 4 for dimensional accuracy and better than ISO tolerance class 4 for running accuracy.
Additional tolerances for tapered bores
are provided in table 3.
The tolerance symbols used in these
­tables are listed together with their defin­
itions in table 4.
mm
µm
1)For
ΔBs
high
4
5
ΔDs
high
80
120
150
Vdp
max
–8
–9
Outer ring
D
over
incl.
50
80
120
low
0
0
Tolerances
0
0
0
low
–120
–150
VBs
max
Kia
max
Sd
max
µm
µm
µm
5
6
4
4
8
8
Kea
max
SD
max
µm
µm
5
6
7
8
9
10
µm
–9
–10
–11
5
5
6
SP tolerances for tapered bores, refer to Table 3.
Values are identical to
those for the inner ring of
the same bearing (ΔBs, VBs)
Table 2
Class UP tolerances
Inner ring
d
over
incl.
Δds1)
high
mm
µm
30
50
50
80
low
Vdp
max
ΔBs
high
µm
µm
0
0
–6
–7
3
3,5
0
0
Outer ring
D
over
incl.
ΔDs
high
low
VDp
max
ΔCs, VCs
mm
µm
50
80
120
1)For
14
minimum operational clearance or preload
after mounting is required.
The bearing rings of individual bearings
are matched at the factory and must be kept
together. (When packed separately, bearing
rings have a serial number.) If bearing rings
are swapped, the “new” radial internal clearance in the bearing could fall outside the
80
120
150
0
0
0
low
–100
–100
VBs
max
Kia
max
Sd
max
µm
µm
µm
2
3
2
2
3
4
Kea
max
SD
max
µm
µm
3
3
4
2
3
3
µm
–6
–7
–8
3
4
4
UP tolerances for tapered bores, refer to Table 3.
Values are identical to
those for the inner ring of
the same bearing (ΔBs, VBs)
specifications and complicate the mounting
procedure.
The values for C1 radial internal clearance
are listed in table 5, on page 16. They are in
accordance with ISO 5753-1:2009 and valid
for unmounted bearings under zero measuring load.
Table 3
Classes SP and UP tolerances for a tapered bore, taper 1:12
B
d2 +Dd2mp
Axial displacement
Bearings in the N 10 series can accommodate thermal elongation of the shaft, within
the bearing. This enables the inner and
outer rings to be mounted with an interference fit. The permissible axial displacement
s from the normal position of one bearing
ring in relation to the other is provided in the
product table.
d1 +Dd1mp
d +Ddmp
C
a
Dd1mp - Dd2mp
2
Half angle of taper:
a = 2° 23’ 9,4”
a
m
Measuring distance a = 2,5 mm
Radial stiffness
Bore diameter Class SP tolerances
d
Δd2mp
Vdp
over
incl.
high
low
max
Class UP tolerances
Δd1mp – Δd2mp1) Δd2mp
Vdp
high
low
high
low
max
Δd1mp – Δd2mp1)
high
low
Radial stiffness depends on the deformation
of the bearing under load and can be expressed as the ratio of the load to bearing
resilience. However, since there is not a dir­
ect linear relationship between bearing resilience and load, constant values for radial
mm
µm
µm
µm
µm
4
5
+4
+5
3
3,5
+3
+3
30
50
1)Δ
d1mp
µm
50
80
+12
+15
0
0
µm
0
0
+7
+8
0
0
0
0
– Δd2mp = angle deviation over the measuring distance m
Table 4
Tolerance symbols
Tolerance
symbol
Definition
Tolerance
symbol
Bore diameter
Definition
Outside diameter
d
Nominal bore diameter
D
Nominal outside diameter
ds
Single bore diameter
Ds
Single outside diameter
dmp
Mean bore diameter; arithmetical mean of the largest and
smallest single bore diameters in one plane
DDs
Deviation of a single outside diameter from the nominal
(DDs = Ds – D)
Dds
Deviation of a single bore diameter from the nominal
(Dds = ds – d)
VDp
Outside diameter variation; difference between the largest
and smallest single outside diameters in one plane
Ddmp
Deviation of the mean bore diameter from the nominal
(Ddmp = dmp – d)
Dd1mp
Deviation of the mean bore diameter at the large end of a
tapered bore from the nominal; arithmetical mean of the
largest and smallest single bore diameters, measured in
one plane in a defined distance from the bearing side face
Dd2mp
Deviation of the mean bore diameter at the small end of a
tapered bore from the nominal; arithmetical mean of the
largest and smallest single bore diameters, measured in
one plane in a defined distance from the bearing side face
Vdp
Bore diameter variation; difference between the largest
and smallest single bore diameters in one plane
Width
B, C
Nominal width of inner ring and outer ring, respectively
Bs, Cs
Single width of inner ring and outer ring, respectively
DBs, DCs
Deviation of single inner ring width or single outer ring
width from the nominal (DBs = Bs – B; DCs = Cs – C)
VBs, VCs
Ring width variation; difference between the largest and
smallest single widths of inner ring and of outer ring,
respectively
Running accuracy
Kia, Kea
Radial runout of inner ring and outer ring, respectively,
of assembled bearing
Sd
Side face runout with reference to bore (of inner ring)
SD
Outside inclination variation; variation in inclination of
outside cylindrical surface to outer ring side face
15
stiffness cannot be quoted. Exact values of
radial stiffness, for bearings in the N 10 series, for a given load can be calculated using
advanced computer methods, but guideline
values are listed in table 6. These values apply to mounted bearings with zero clearance
under static conditions and subjected to
moderate loads.
Equivalent loads
The equivalent dynamic bearing load can be
calculated using
P = Fr
The equivalent static bearing load can be
calculated using
• Housing and shaft seats and abutments
meet the accuracy requirements for precision applications.
The speed ratings must be reduced when:
• operational clearance is smaller than
2 μm
• preload is set
• the housing and shaft seats and abutments do not meet accuracy
requirements
Rollers of hybrid bearings are made of bearing grade silicon nitride Si3N4.
The bearings undergo a special heat
treatment to achieve a good balance between hardness and dimensional stability.
The hardness of the rings and rolling elem­
ents is optimized for wear-resistance and
the bearing rings are heat stabilized to accommodate temperatures up to 150 °C.
Table 5
Radial internal clearance
The values provided for oil lubrication apply
to the oil-air lubrication method and should
be reduced if other oil lubrication methods
are used. The values provided for grease lubrication are maximum values that can be
attained with good lubricating grease that
has a low consistency and low viscosity.
P0 = Fr
where
P = equivalent dynamic bearing load [kN]
P0= equivalent static bearing load [kN]
Fr = radial component of the load [kN]
Attainable speeds
The attainable speeds listed in the product
table should be regarded as guideline
values. They are valid under the following
conditions:
• The bearings have small operational
clearance (2 to 3 μm).
Cage material
Bearings in the N 10 series have a cage
made of carbon fibre reinforced polyetheretherketone (PEEK) († fig. 1) that can
withstand temperatures up to 150 °C.
The technical specifications of carbon ­fibre
reinforced PEEK are provided in table 7.
Materials and heat
treatment
The rings and rollers of all-steel bearings in
the N 10 series are made from SKF Grade 3
steel, in accordance with ISO 683-17:1999.
Bearing
Radial internal
clearance
C1
min
max
Bore diameter
d
Size
mm
–
μm
40
45
50
55
60
08
09
10
11
12
15
17
17
20
20
25
30
30
35
35
65
70
75
80
13
14
15
16
20
25
25
25
35
40
40
40
Table 6
Static radial stiffness
Bearing
Bore diameter
d
Size
Static radial stiffness
of all-steel bearings
of hybrid bearings
mm
–
N/μm
40
45
50
55
60
08
09
10
11
12
155
176
194
229
250
172
196
215
254
277
65
70
75
80
13
14
15
16
271
305
303
347
301
339
337
385
16
Table 7
Technical specifications of carbon fibre
reinforced polyetheretherketone (PEEK)
Property
Specification
Density
[g/cm3]
1,41
Thermal linear
expansion coefficient
[10-6 /K]
25
Elasticity traction
modulus
[MPa]
7 700
Melting point
[°C]
340
Packaging
SKF super-precision bearings are distributed in new SKF illustrated boxes († fig. 2).
Bearings in the N 10 series are usually supplied in a single box. However, if the bearing
rings are packed separately, they are identified by a serial number and must be kept
together.
Fig. 2
Fig. 1
Designation system
C
The designations for SKF bearings in the
N 10 series are provided in table 8 ­together
with their definitions.
Table 8
Designation system for SKF high-speed super-precision single row cylindrical roller bearings
in the N 10 series
Example:
N 1016 KPHA/HC5SP
N
10
16
K
PHA
/
HC5
SP
Bearing design
N
Single row cylindrical roller bearing with integral flanges on the inner ring
Dimension Series
10
In accordance with ISO Dimension Series 10
Bearing size
08
to
16
Bore shape
K
(x5) 40 mm bore diameter
(x5) 80 mm bore diameter
Tapered bore (taper 1:12)
Cage material and design
PHA
Carbon fibre reinforced polyetheretherketone (PEEK), outer ring centred,
high-speed design
Rolling elements
–
HC5
Tolerance class
SP
UP
Carbon chromium steel (no designation suffix)
Bearing grade silicon nitride Si3N4 (hybrid bearings)
Dimensional accuracy approximately in accordance with ISO tolerance
class 5 and running accuracy approximately in accordance with ISO
tolerance class 4
Dimensional accuracy approximately in accordance with ISO tolerance
class 4 and running accuracy better than ISO tolerance class 4
17
Super-precision single row cylindrical roller bearings
d 40 – 80 mm
B
r2
r4
D E
s
r1
r3
d d1
Principal dimensions
Basic load ratings
dynamic
static
Fatigue
load limit
d
C
Pu
D
B
mm
C0
kN
Attainable speeds
when lubricating with
grease
oil-air
Mass
Designation
kN
r/min
kg
–
40
68
68
15
15
23,3
23,3
25
25
2,9
2,9
30 000
32 000
36 000
38 000
0,190
0,172
N 1008 KPHA/SP
N 1008 KPHA/HC5SP
45
75
75
16
16
27
27
30
30
3,45
3,45
28 000
30 000
34 000
36 000
0,240
0,202
N 1009 KPHA/SP
N 1009 KPHA/HC5SP
50
80
80
16
16
28,6
28,6
33,5
33,5
3,8
3,8
26 000
28 000
30 000
32 000
0,260
0,217
N 1010 KPHA/SP
N 1010 KPHA/HC5SP
55
90
90
18
18
37,4
37,4
44
44
5,2
5,2
22 000
24 000
28 000
30 000
0,380
0,316
N 1011 KPHA/SP
N 1011 KPHA/HC5SP
60
95
95
18
18
40,2
40,2
49
49
5,85
5,85
20 000
22 000
26 000
28 000
0,400
0,330
N 1012 KPHA/SP
N 1012 KPHA/HC5SP
65
100
100
18
18
42,9
42,9
54
54
6,3
6,3
20 000
22 000
24 000
26 000
0,430
0,354
N 1013 KPHA/SP
N 1013 KPHA/HC5SP
70
110
110
20
20
53,9
53,9
69,5
69,5
8
8
18 000
20 000
22 000
24 000
0,610
0,501
N 1014 KPHA/SP
N 1014 KPHA/HC5SP
75
115
115
20
20
52,8
52,8
69,5
69,5
8,15
8,15
17 000
19 000
20 000
22 000
0,640
0,531
N 1015 KPHA/SP
N 1015 KPHA/HC5SP
80
125
125
22
22
66
66
86,5
86,5
10,2
10,2
16 000
18 000
19 000
20 000
0,880
0,731
N 1016 KPHA/SP
N 1016 KPHA/HC5SP
18
ra
Da
da
C
Dimensions
d
Abutment and fillet dimensions
d1
~
E
~
r1,2
min
r3,4
min
s1)
mm
da
min
da
max
Da
min
Da
max
ra
max
mm
40
50,6
50,6
61
61
1
1
0,6
0,6
1,5
1,5
45
45
59
59
62
62
63
63
1
1
45
56,3
56,3
67,5
67,5
1
1
0,6
0,6
1,5
1,5
50
50
65
65
69
69
70
70
1
1
50
61,3
61,3
72,5
72,5
1
1
0,6
0,6
1,5
1,5
55
55
70
70
74
74
75
75
1
1
55
68,2
68,2
81
81
1,1
1,1
0,6
0,6
1,5
1,5
61,5
61,5
79
79
82
82
83,5
83,5
1
1
60
73,3
73,3
86,1
86,1
1,1
1,1
0,6
0,6
1,5
1,5
66,5
66,5
84
84
87
87
88,5
88,5
1
1
65
78,2
78,2
91
91
1,1
1,1
0,6
0,6
1,5
1,5
71,5
71,5
89
89
92
92
93,5
93,5
1
1
70
85,6
85,6
100
100
1,1
1,1
0,6
0,6
2
2
76,5
76,5
98
98
101
101
103,5
103,5
1
1
75
90,6
90,6
105
105
1,1
1,1
0,6
0,6
2
2
81,5
81,5
102
102
106
106
108,5
108,5
1
1
80
97
97
113
113
1,1
1,1
0,6
0,6
2
2
86,5
86,5
110
110
114
114
118,5
118,5
1
1
1) Permissible
axial displacement from the normal position of one bearing ring in relation to the other.
19
Setting the highest standard for
precision bearings
SKF has developed and is continuing to
develop a new, improved generation of superprecision bearings. The new assortment
delivers improved accuracy and extended
bearing service life when compared to
previous designs.
Super-precision
angular contact ball
bearings
Bearings in the 718 (SEA)
series
Bearings in the 718 (SEA) series provide
optimum performance in applications where
a low cross section and high degree of rigidity, speed and superior accuracy are critical
design parameters. They are particularly
suitable for machine tool applications, multi­
spindle drilling heads, robotic arms, measuring devices, racing car wheels and other
precision applications. The standard assortment accommodates shaft diameters ranging from 10 to 160 mm.
Bearings in the 719 .. D (SEB)
and 70 .. D (EX) series
For applications where a high load carrying
capacity is an additional operational requirement, SKF offers high-capacity bearings in
the 719 .. D (SEB) and 70 .. D (EX) series.
The ability of the new design super-precision bearings in these two series to accommodate heavy loads in applications where
radial space is often limited, makes them an
excellent choice for demanding applications.
Open bearings in the 719 .. D (SEB) series
accommodate shaft diameters ranging from
10 to 360 mm; sealed bearings from 10 to
150 mm.
Open bearings in the 70 .. D (EX) series
accommodate shaft diameters ranging from
6 to 240 mm; sealed bearings from 10 to
150 mm.
Bearings in the S719 .. B
(HB .. /S) and S70 .. B
(HX .. /S) series
High-speed sealed bearings in the S719 .. B
(HB .. /S) and S70 .. B (HX .. /S) series can
virtually eliminate the problem of premature
bearing failures resulting from contamin­
ation. The standard assortment accommodates shaft diameters ranging from 30 to
120 mm. These relubrication-free bearings
are particularly suitable for metal cutting
and woodworking machines. The bearings
are also available in an open variant.
Bearings in the 719 .. E (VEB)
and 70 .. E (VEX) series
Bearings in the 72 .. D (E 200)
series
High-capacity bearings in the 72 .. D (E 200)
series offer solutions to many bearing
arrangement challenges. Their ability, among
others, to provide a high degree of rigidity and
accommodate heavy loads at relatively high
speeds, is beneficial for a variety of applications. The extended range of bearings in this
series now accommodates shaft diameters
ranging from 7 to 140 mm. And, there is
also a relubrication-free, sealed variant,
available on request.
20
Compared to high-speed B design bearings,
high-speed E design bearings have a higher
speed capability and can accommodate
heavier loads. This desirable combination
makes these bearings an excellent choice
for demanding applications.
Open bearings in the 719 .. E (VEB) series
accommodate shaft diameters ranging from
8 to 120 mm; sealed bearings from 20 to
120 mm.
Open bearings in the 70 .. E (VEX) series
accommodate shaft diameters ranging from
6 to 120 mm; sealed bearings from 10 to
120 mm.
Bearings made from
NitroMax steel
In extremely demanding applications such
as high-speed machining centres and milling machines, bearings are frequently subjected to difficult operating conditions such
as very high speeds, thin-film lubrication
conditions, and contaminated and corrosive
environments. To enable longer bearing
service life and reduce the costs associated
with downtime, SKF has developed a superior high-nitrogen steel.
The SKF assortment of super-precision
angular contact ball bearings made from
NitroMax steel have ceramic (bearing grade
silicon nitride) rolling elements as standard.
Super-precision
cylindrical roller
bearings
SKF produces super-precision single row
and double row cylindrical roller bearings.
The characteristic features of these bearings
are a low cross sectional height, high load
carrying capacity, high rigidity and highspeed capability. They are therefore particularly well suited for machine tool spindles
where the bearing arrangement must
accommodate heavy radial loads and high
speeds, while providing a high degree of
stiffness.
Single row cylindrical roller bearings are
produced in the N 10 series as basic design
bearings and as high-speed design bearings. High-speed single row cylindrical roller
bearings in the N 10 series are available
with a tapered bore only and for shaft diameters ranging from 40 to 80 mm. Compared
to previous high-speed design, they can
accommodate a speed increase of up to 30%
in grease lubricated applications and up to
15% in oil-air lubricated applications.
Double row cylindrical roller bearings are
produced as standard in the NN design and
NNU design.
Super-precision
double direction
angular contact thrust
ball bearings
Super-precision
angular contact thrust
ball bearings for screw
drives
Double direction angular contact bearings,
as their name implies, were developed by
SKF to axially locate machine tool spindles
in both directions.
The new optimized design of super-precision bearings in the BTW series consists
of a set of two single row angular contact
thrust ball bearings, arranged back-to-back.
This configuration enables the bearings to
accommodate axial loads in both directions
while providing a high degree of system
rigidity. These bearings can accommodate
higher speeds compared to bearings in the
former 2344(00) series. The bearings are
available for shaft diameters ranging from
35 to 200 mm.
The redesigned high-speed BTM series
accommodate higher speeds, anywhere
from 6% to 12% depending on the size;
minimize heat generation, even at higher
speeds; provide high load carrying capacity
and maintain a high degree of system rigidity. The range of BTM bearings series has
been expanded to accommodate shaft
diameters from 60 to 180 mm.
Single direction angular contact thrust ball
bearings in the BSA and BSD (BS) series are
available for shaft diameters ranging from
12 to 75 mm. These bearings are characterized by superior axial stiffness and high
axial load carrying capacity.
Double direction angular contact thrust
ball bearings in the BEAS series have been
developed for machine tool applications
where space is tight and easy mounting is
required. The bearings are available for shaft
diameters ranging from 8 to 30 mm. Bearings in the BEAM series, which can accommodate shaft diameters ranging from 12 to
60 mm, can be bolt-mounted to an associated component.
Cartridge units are another solution for
simple and quick mounting. Units in the
FBSA (BSDU and BSQU) series incorporate
SKF single direction angular contact thrust
ball bearings and can accommodate shaft
diameters ranging from 20 to 60 mm.
Super-precision axial­
radial cylindrical roller
bearings
SKF axial-radial cylindrical roller bearings
are suitable for arrangements that have
simultaneously acting (radial and axial)
loads as well as moment loads.
Their internal design, together with close
tolerance manufacturing processes, enable
these bearings to attain better than P4 running accuracy.
Axial-radial cylindrical roller bearings are
commonly used to support rotating tables,
indexing tables and milling heads.
21
D
SKF – the knowledge engineering
company
From one simple but
inspired solution to
a misalignment
problem in a textile
mill in Sweden, and
fifteen employees in
1907, SKF has
grown to become a
global industrial
knowledge leader.
Over the years, we have built on our expertise in bearings, extending it to seals, mechatronics, services and lubrication systems.
Our knowledge network includes 46 000
employees, 15 000 distributor partners,
offices in more than 130 countries, and a
growing number of SKF Solution Factory
sites around the world.
Research and development
Meeting the toughest challenges
Working for a sustainable future
Our network of knowledge and experience,
along with our understanding of how our
core technologies can be combined, helps
us create innovative solutions that meet the
toughest of challenges. We work closely with
our customers throughout the asset life
cycle, helping them to profitably and
responsibly grow their businesses.
Since 2005, SKF has worked to reduce the
negative environmental impact from our
operations and those of our suppliers. Our
continuing technology development resulted
in the introduction of the SKF BeyondZero
portfolio of products and services which improve efficiency and reduce energy losses,
as well as enable new technologies harnessing wind, solar and ocean power. This
combined approach helps reduce the environmental impact both in our operations and
our customers’ operations.
We have hands-on experience in over forty
industries based on our employees’ knowledge of real life conditions. In addition, our
world-leading experts and university partners pioneer advanced theoretical research
and development in areas including tribology, condition monitoring, asset management and bearing life theory. Our ongoing
commitment to research and development
helps us keep our customers at the forefront
of their industries.
SKF Solution Factory makes SKF knowledge and manufacturing expertise
available locally to provide unique solutions and services to our customers.
22
Working with SKF IT and logistics systems and application experts, SKF
Authorized Distributors deliver a valuable mix of product and application
knowledge to customers worldwide.
Innovative solutions
Whether the application is linear or rotary
or a combination, SKF engineers can work
with you at each stage of the asset life cycle
to improve machine performance by looking
at the entire application. This approach
doesn’t just focus on individual components
like bearings or seals. It looks at the whole
application to see how each component interacts with each other.
an
d
dc
om
m
ai
n
ission
Spec
ific
Our objective is to help our customers
improve productivity, minimize maintenance, achieve higher energy and resource
efficiency, and optimize designs for long
service life and reliability.
SKF Life Cycle
Management
st
te
Working closely with you
Man
ufa
ctu
re
an
d
SKF Life Cycle Management is how we combine our technology
platforms and advanced services, and apply them at each stage
of the asset life cycle, to help our customers to be more
successful, sustainable and profitable.
ion
at
int
Ma
Our knowledge
– your success
Design and develo
p
rep
air
Opera
te and monitor
n
la
tal
Ins
D
Bearings
SKF is the world leader in the design, development
and manufacture of high performance rolling
bearings, plain bearings, bearing units and
housings.
Machinery maintenance
Condition monitoring technologies and maintenance services from SKF can help minimize
unplanned downtime, improve operational
efficiency and reduce maintenance costs.
Sealing solutions
SKF offers standard seals and custom engineered
sealing solutions to increase uptime, improve
machine reliability, reduce friction and power
losses, and extend lubricant life.
Design optimization and verification
SKF can work with you to optimize current
or new designs with proprietary 3-D modelling software that can also be used as a
virtual test rig to confirm the integrity of the
design.
Mechatronics
SKF fly-by-wire systems for aircraft and drive-bywire systems for off-road, agricultural and forklift
applications replace heavy, grease or oil consuming
mechanical and hydraulic systems.
Lubrication solutions
From specialized lubricants to state-of-the-art
lubrication systems and lubrication management
services, lubrication solutions from SKF can help to
reduce lubrication related downtime and lubricant
consumption.
Actuation and motion control
With a wide assortment of products – from actuators and ball screws to profile rail guides – SKF
can work with you to solve your most pressing
linear system challenges.
23
The Power of Knowledge Engineering
Seals
Bearings
and units
Mechatronics
Lubrication
systems
Services
Drawing on five areas of competence and application-specific expertise amassed over more than 100
years, SKF brings innovative solutions to OEMs and production facilities in every major industry worldwide. These five competence areas include bearings and units, seals, lubrication systems, mechatronics
(combining mechanics and electronics into intelligent systems), and a wide range of services, from 3-D
computer modelling to advanced condition monitoring and reliability and asset management systems.
A global presence provides SKF customers uniform quality standards and worldwide product availability.
®SKF and SNFA are registered trademarks of the SKF Group.
©SKF Group 2012
The contents of this publication are the copyright of the publisher and may not be reproduced (even
extracts) unless prior written ­permission is granted. Every care has been taken to ensure the accuracy
of the information contained in this publication but no liability can be accepted for any loss or damage
whether direct, indirect or consequential arising out of the use of the information contained herein.
PUB BU/P9 07016/2 EN · November 2012
This publication complements information about SKF bearings in the N 10 series in the SKF publication High-precision bearings (Publication No. 6002).
www.skf.com/superprecisionbearings
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