Reversing Transmission System - UD Mechanical Engineering

Reversing Transmission System - UD Mechanical Engineering
SCHILLER GROUNDS CARE, INC.
Reversing Transmission
System
Final Report
Hugh Kettler, Ed Kowalski, Tom Malone, Bill Power, Zach Schoepflin
12/12/2009
Here is presented a report for Schiller Grounds Care, cataloging the design and validation processes.
Contents
Executive Summary....................................................................................................................................... 3
Introduction and Project Scope .................................................................................................................... 4
Design Requirements .................................................................................................................................... 4
Wants and Constraints .............................................................................................................................. 4
Metrics and Target Values ........................................................................................................................ 6
Benchmarking ........................................................................................................................................... 7
Concept Generation and Selection ............................................................................................................... 7
Parallel Worms .......................................................................................................................................... 7
Double Helical and Spur Gear ................................................................................................................... 8
Comparison ............................................................................................................................................... 9
Detailed Design ........................................................................................................................................... 10
Gearing Subsystem ................................................................................................................................. 10
“Collapsible” Driveshaft Subsystem ........................................................................................................ 11
Worm Movement Subsystem ..................................................................................................................... 11
Full design ............................................................................................................................................... 12
Performance Validation .............................................................................................................................. 12
Gear Housing........................................................................................................................................... 14
Center of Gravity ..................................................................................................................................... 14
Power Output.......................................................................................................................................... 15
Cost of Parts ............................................................................................................................................ 15
Cost of Assembly ..................................................................................................................................... 16
Number of Parts ...................................................................................................................................... 16
Weight ..................................................................................................................................................... 16
Path Forward............................................................................................................................................... 17
Single-Piece Transmission Housing ......................................................................................................... 17
Worm ...................................................................................................................................................... 17
Optimization for Gear Sizing ................................................................................................................... 17
Durability Testing .................................................................................................................................... 17
Control System ........................................................................................................................................ 18
Future Additional Considerations ........................................................................................................... 18
Acknowledgements..................................................................................................................................... 18
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Table 1:
Table 2:
Table 3:
Table 4:
Table of wants, as discussed by communication with Schiller....................................................... 5
Table of metrics and target values, as discussed by communication with Schiller ....................... 7
Estimated cost of parts for the final product ............................................................................... 15
Metrics of success for prototype and proposed casted housing ................................................. 16
Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Figure 7:
Figure 8:
Figure 9:
Parallel worms concept ................................................................................................................. 8
Dual helical and spur gear concept ............................................................................................... 9
Comparison of two concepts focusing on housing width ............................................................. 9
Gearing subsystem ...................................................................................................................... 10
"Collapsible" driveshaft subsystem............................................................................................. 11
Worm movement subsystem ...................................................................................................... 11
Full prototype design .................................................................................................................. 12
Built prototype attached to four-stroke motor .......................................................................... 13
Solid model of single-piece transmission housing ...................................................................... 14
Executive Summary
Schiller Grounds Care, Inc. is a leading manufacturer of gardening and grounds care equipment.
One of Schiller’s best-selling pieces of equipment is the Mantis miniature tiller and cultivator. Schiller
has asked the University of Delaware design team to redesign the transmission of the Mantis tiller to
incorporate a reversing feature.
In order to make the Mantis more versatile as an all-purpose machine, Schiller desires the
option of having the output shaft rotate in the opposite direction from the perspective of the user. In
doing so, the Mantis will be more effective for attachments such as a sweeping arm or snow thrower.
Currently, the Mantis uses a worm and worm gear system driven by a combustion engine or electric
motor that has been optimized for tilling torque and speed. Because the device is primarily used for
tilling, Schiller wishes to incorporate this reverse feature into the current machine without changing the
normal tilling output or drastically increasing the size of the transmission housing. The main purpose of
this project is to design such a feature, focusing solely on the gearing involved and the method for
actuating the reversing mechanism.
Through communication with Schiller, the design team compiled a list of designable and
measurable metrics of success and target design values. A design concept to best achieve these success
metrics was envisioned and fabricated into a prototype. The functionality and success of the prototype
was then tested. From these results, the design team worked with Schiller to decide the best path
forward for further testing and eventual incorporation of the reversing design into the commercial
product.
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Introduction and Project Scope
Schiller Grounds Care, Inc. was established in early 2009 with the merger of Schiller-Pfeiffer, Inc.
and Commercial Grounds Care, Inc. Schiller Grounds Care, Inc. manufactures gardening, landscaping,
and grounds care equipment brand names such as Little Wonder®, Classen®, Bob-Cat®, and Mantis®.
The Mantis brand has been on the market for over twenty-five years and boasts the Mantis
tiller/cultivator, the world’s best-selling tiller with over one million customers. Although the Mantis
tiller already has attachments for tasks such as edging, dethatching, and aerating, Schiller wishes to
expand their market and sell additional attachments for processes like sweeping and snow-throwing. In
order to make effective attachments for such tasks, the output shaft of the Mantis tiller should rotate in
the reverse direction from the proper tilling direction, so that the debris is thrown away from the user
instead of towards. In order to more effectively design a reversing feature, the design was divided into
three subsystems: the gearing subsystem including the necessary gears for reversing the output shaft,
the actuation subsystem including the way in which the reverse feature is engaged in the transmission
housing, and the control subsystem including the interface through which the user will manage the
reversing feature. Schiller has asked the design team to focus solely on the gearing and actuation
subsystems for this project.
Design Requirements
Wants and Constraints
The design team spoke with representatives from Schiller in order to better define their wants
for the design. One important consideration specified was for the transmission to occupy a footprint
very similar to the current design. The size and shape of the transmission affect both the placement of
the tilling blades and attachments and where the engine must be placed on the tiller. Specifically, the
design team must concern itself with the width of the transmission housing for our new design. As the
tiller is dragged through the ground, the transmission creates a resistance through the soil. A larger
transmission housing will increase this resistance, making it harder to use the tiller for its primary
function.
Schiller also requested the team to consider the center of gravity of the tiller. One of the
biggest reasons for the success of the Mantis is its low center of gravity. If the center of gravity of the
machine falls outside the width of the tines while tilling, the blades will not dig into the soil, making the
machine less useful as a tiller. It is important for the functioning of the machine to keep the relatively
same center of gravity and not raise it too much.
The Mantis tiller is designed and engineered for optimal tilling success. The output torque,
speed, and power of the machine are carefully managed through the engine and gear ratios in order to
till efficiently. Schiller expressed that they would not like to change or reduce the output in the forward
direction in order to maintain these optimizations.
Next, Schiller expressed a desire for the new transmission to have a similar cost of parts and
assembly to the old transmission, so the reversing mechanism can be included in the tiller without
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having to increase, or at least not drastically increase, the cost in order to preserve the current profit
margin.
Another want for the new transmission is for it to have a simple actuation; the process of
switching the tiller from forward to reverse, and vice versa, should be clear and should not involve more
than a couple of easy-to-remember steps. This way, it will appeal to gardeners who are not especially
mechanically inclined. In addition to a simple interface, the transmission should be easy to manually
engage in both forward and reverse. If the entire target demographic of the tiller is not strong enough
to switch the tiller between gears, Schiller may lose current or potential customers. As a safety concern
with the actuation, Schiller expressed a desire for the engine to be shut off and the tines removed
during shifting. This is necessary to avoid accidental injury to the user. Because of this safety constraint,
the team was able to disregard concepts concerning shifting a running system.
The company wants the new transmission to be element-resistant and durable. Because the
tiller is usually operated to churn up the ground, soil, plants, water, etc., debris will be coming into
contact with the housing of the transmission. In order to ensure reliable operation, the housing must be
able to withstand such contact. The company’s reputation depends on how well its products hold
together over their expected lifespan, and therefore something as critical as the tiller’s transmission
must be capable of properly operating for as long as possible. This will help maintain the reputation of
the Schiller name and their ability to sell the tiller and other products.
Mechanically, the possible design concepts are constrained by the power output from the
motor. Schiller provides three distinct motors for the Mantis: a two-stroke, a four-stroke, and an
electric. The finalized design must be compatible with these motors, particularly the current four-stroke
engine. In addition, the tines on the tiller have a set output torque for a given engine RPM that should
be matched by the design.
Table 1: Table of wants, as discussed by communication with Schiller
Wants
Relatively Same Footprint
Relatively Same Center of Gravity
Relatively Same Tilling Output
Low Cost
Simple Design
Easy to engage
Durability/Element Resistant
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Metrics and Target Values
The width of the gear housing in the transmission is a metric that the design team aims to meet.
The width of the current transmission housing at its widest point is 2.375in. The design team is
designing for no more than an additional 0.375in to each side of the transmission, giving a total
maximum width of 3.125in. While tilling, the gear housing is fully under the surface of the ground being
tilled. Any drastic increase in the width of the gear housing will increase resistance through the soil
being tilled, making the job require more physical labor. Additionally, in an ideal design, the gear
housing with the reversing transmission will be identical to the current design, eliminating the need to
alter the assembly or manufacturing process of the current transmission housing.
The center of gravity of the tiller is a very important aspect. If the center of gravity rests too
high on the machine, the tines will not dig into the soil appropriately, severely decreasing the
effectiveness of the machine. As a result, the team is designing to maintain as close to the current
center of gravity as possible. The design should not raise the current center of gravity by more than
0.5in.
The current four-stroke tiller outputs a maximum 31ft-lbs of torque at the tines, and a maximum
rotational velocity of about 240 RPM. These current values are kept as target values for the torque and
RPM metrics for the forward direction of the reversing feature. As mentioned above, it is important for
Schiller to maintain the normal, forward output of the device.
The low cost of the Mantis is made possible by the low cost of manufacturing and assembly of
the device. The current cost of parts and labor for one tiller is $40.83. In order to maintain the low
price of the Mantis, the target value for total cost of parts is chosen as $60. Additionally, the design
team is designing for an assembly cost of less than $25. By designing a reversing transmission for under
this target total cost, the retail price of the Mantis will not have to increase by very much, making the
tiller still accessible to the current target customers.
Factored into the cost of parts and cost of assembly is the added number of parts of the
transmission. More parts leads to longer assembly times, ultimately leading to higher assembly costs.
More parts also directly affect the total cost of parts. To cross-correlate the wants and reach a desirable
design, the team is targeting to add no more than ten total parts to the current transmission.
The Mantis is designed as an easily-portable miniature tiller, able to be used and carried by
owners of average size and weight. The lightweight design is an important selling point and makes the
tiller widely accessible. It is important for the added reversing mechanism to not add any substantial
weight to the current design. Schiller and the design team have chosen to not add more than 5lb to the
current design, in order to maintain the portability of the tiller.
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Table 2: Table of metrics and target values, as discussed by communication with Schiller
Metrics
Target Value
Housing dimensions
raised ≤ 0.75in wide
Center of gravity
raised ≤ 0.5in
Output (power, torque, rpm)
31ft∙lb, 240RPM
Cost of parts
raised ≤ $34 ($60 total)
Cost of assembly
raised ≤ $10.50 ($25 total)
Number of parts
raised ≤ 10
Weight
raised ≤ 5lb
Benchmarking
In order to begin the step of concept generation, the team performed some benchmarking to
discuss some early possible solutions to the problem. Competitive models, such as the miniature tillers
manufactured by Honda, Craftsman, and Yard Machines have been investigated for comparison. None
of the competing models exhibited possible working solutions to this unique problem. The only tillers
found with reversing features are large, rear-tine tillers, and their solutions are not applicable to this
problem. Additionally, the team investigated certain “combo tools”, like those of Echo Power
Equipment, capable of different attachments with different features including tiller/cultivators. None
seemed to provide a feasible solution to the problem, however, as all the directional features were
included in the attachments only, if ever.
The team also investigated current technology before attacking the design process. They
became familiar with the current Mantis transmission and assembly process. Additionally, they
researched previous work in the field. A previous design team has already proposed possible solutions
to this problem. These ideas include a new gearbox and a planetary gear system, which upon further
consideration seem too complicated and pricey for this situation.
Concept Generation and Selection
The design team explored a number of different possible approaches to this problem. The
gearing subsystem required some specific expertise. In order to better understand the requirements of
the system, communication was opened with the sponsor and with local gear distributors and
manufacturers. Several designs resulted, the most feasible of which being one including two worms in
parallel and one with a double helical and spur gear concept.
Parallel Worms
This concept consists of two worms simultaneously being rotated by the drive shaft. One worm
will have right hand threads while the other will have left hand threads. One of the two worms will be in
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contact with the worm gear which causes the tines to rotate. To make the tines rotate the other way,
the worms will rotate 180° to allow the oppositely-threaded worm gear to come in contact with the
worm gear which will, in turn, cause the tines to rotate in the opposite direction.
Figure 1: Parallel worms concept
Double Helical and Spur Gear
In order to achieve the desired reversing feature, this design utilizes a collapsible shaft and an
additional helical gear. A spur gear, with a diameter slightly larger than that of the current helical gear,
is fixed to the tine shaft. The additional helical gear and another spur gear are located on shaft directly
above the tine shaft with the spurs connected. When the user wishes to engage the reversing feature,
he or she will cause the drive shaft to collapse and raise the worm, which will act analogous to a rack
and pinion with the tine shaft freely rotating. The worm will eventually engage the upper helical gear.
When the tiller is run in this new position, the worm will turn the upper helical gear and spur gear,
which in turn will drive the lower spur gear and tine shaft in the reverse direction. A model of the
design can be found below.
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Figure 2: Dual helical and spur gear concept
Comparison
Through communication with the sponsor, it was apparent that the most important metric was
the dimensions of the transmission house. Too wide a transmission housing has deleterious
consequences on the Mantis’ ability to till effectively. The concepts’ performance in this category
helped drive the concept selection process. The double helical and spur gear concept was chosen as a
result. The comparison of the two concepts based on width can be seen below. The parallel worm
concept is shown on the left, while the “combo” gear concept is shown on the right.
Figure 3: Comparison of two concepts focusing on housing width
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The actuation subsystem for the dual helical and spur gear design was further divided into
“collapsible” driveshaft and worm movement systems. The design will utilize a collapsible drive shaft in
order to articulate the two helical gears. The design for a collapsible drive shaft involves the use of a DD
shaft mating. A shaft containing the worm will articulate inside a drive shaft driven by the motor.
Detailed Design
The design team spent time more definitely realizing and developing the chosen concept into a
full design, ready to be implemented into a Mantis tiller. After more consideration, the design team
decided to add an additional subsystem to the design giving a total of three: the worm, worm gear, and
spur gear system; the collapsible driveshaft system; and a new system including the method for
articulating the collapsing driveshaft.
Gearing Subsystem
This subsystem incorporates the different gears that transmit power from the engine to the tine shaft.
The worm meshes to either the upper or lower helical gear, which then turns the connected spur gear
and, through the meshing of the spur gears, the other helical gear. The lower helical gear rotates, either
directly from the worm or from its attached spur gear, and spins the tine shaft. Based on the sizing of
the worm gears, the spur gears are easily chosen as having a 3in pitch diameter. Spur gears with a 3in
pitch diameter are just large enough to maintain no interference between the worm gears and also
easily manufactured as standard without requiring any custom gear requests.
Figure 4: Gearing subsystem
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“Collapsible” Driveshaft Subsystem
This subsystem employs a “collapsible” driveshaft in order to allow the desired axial motion of
the worm. The shaft leading upwards from the worm mates with and is driven by the upper driveshaft
through a DD shaft profile. The center of the driveshaft has a bored, hollow center using the same DD
profile that allows the worm shaft to move up to three inches in the axial direction. The upper
driveshaft mates with the engine through a hexagonal top profile, and is held in place by a tapered roller
bearing press-fit into the housing.
Figure 5: "Collapsible" driveshaft subsystem
Worm Movement Subsystem
This subsystem is responsible for controlling the axial motion of the worm. A fork straddles the
worm and moves in the axial direction along a low-profile linear bearing that is attached to the housing.
The fork is moved up and down along guides located on top of the transmission housing, and is located
and locked into place by a locking pin.
Figure 6: Worm movement subsystem
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Full design
A model of the full design can be found below.
Figure 7: Full prototype design
Performance Validation
A prototype was built in order to prove the functionality of the proposed design. The
transmission housing was modeled as a box, as seen in the design pictures above. One of the side plates
was manufactured out of polycarbonate in order to see the gear work inside. The prototype was
attached to a four-stroke Mantis engine and run at a low throttle. The engine was attached backwards
from the conventional Mantis in order to better accommodate the pin-locking system on the top of the
housing. The prototype can be found below.
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Figure 8: Built prototype attached to four-stroke motor
After the prototype was built and proven to work as designed, it was validated to assess its
performance in the metrics of success. Because the prototype was built as an aluminum box and not as
a solid-piece casted housing like it would be when fully integrated into the Mantis product line, the
weight and center of gravity metrics could not be directly measured. As a result, a solid model of a
single-piece housing was designed and validated through SolidWorks. The model is found below.
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Figure 9: Solid model of single-piece transmission housing
The testing and validation focused on ensuring all of the metrics of success were met. The
design can be considered a general success provided it meets or exceeds each of the target values. Each
metric was evaluated and tested individually to determine if it fell within the acceptable range of target
values.
Gear Housing
The gear housing width target value was set at 3.125 inches. The prototype housing width at its
widest point was measured using calipers to be 2.55 inches. The proposed final casted housing modeled
in SolidWorks was modeled to be 3.125 inches at its widest point to allow for maximum housing wall
thickness while still remaining within the target value.
Center of Gravity
The acceptable rise in the center of gravity was set at 0.5in in order to keep the weight of the
motor above the tines. Using element analysis in SolidWorks, it was possible to calculate the center of
gravity of the transmissions. The center of gravity of the prototype was lowered 0.825in while the
casted housing was lowered 0.755in, which are both acceptable values. The weight of the engine is
more than the transmission housing. By increasing the weight of the housing below the motor, it
actually lowers the center of gravity, which is highly beneficial for the Mantis in the proper tilling
position.
14
Power Output
The desired power output was the current tilling output, with a maximum of 31ft∙lb of torque
and 240RPM. Although additional gears were added to the transmission, the optimized gear ratio of
42:1 was kept between the worm and worm gear and the spur gears were matched to maintain identical
speed between the two output shafts. Because of this matching, there is only a negligible frictional
change to the power output in both the constructed prototype and the proposed single-piece housing.
Cost of Parts
Using the current cost of parts for the Mantis tiller, the cost of parts for the proposed design
was speculated. The price of the current worm and housing were increased five and ten percent,
respectively, in order to conservatively estimate the higher cost due to material volume increase for
each part. The prices for the bearings, tine shafts, worm gears, etc. were taken as twice the current
value, because the same parts can be used in the proposed design. The fork was estimated as half the
housing cost, because it is anticipated that the fork will be formed by similar processes but contain
approximately half the material volume. The price for the spur gear was estimated at half the cost of
the worm gear, based off of estimates provided by gear manufacturers. A table of the anticipated cost
of parts for the proposed design is found below.
Table 3: Estimated cost of parts for the final product
Part Name
Worm
Thrust Bearing
Worm Gear (2)
Worm gear thrust bearing
Tine shafts
Tine shaft bushings
Tine shaft seals
Tine shaft seal retainers
Gasket
Housing Cover
Transmission House
Screws
Spur Gear (2)
Drive Shaft
Fork
Fork Bearings
Estimated Cost of Parts
4.347
0.42
15.68
0.376
7.17
1.48
0.06
0.208
0.078
0.5
7.2853
0.124
7.84
1.587
3.64265
0.64
Total: $52.00
This proposed cost of parts list raises the cost of parts of the Mantis tiller by an estimated
$25.65. This falls within the target value of raising the cost of parts by $34, further validating the design.
15
Cost of Assembly
The time of assembly for the proposed final product was estimated using standardized assembly
time charts provided as supplemental material in MEEG304 – Machine Design: Elements, a junior-year
design course in the University of Delaware Mechanical Engineering curriculum. Using these charts, the
current Mantis transmission assembly was estimated to take sixty seconds. The new proposed Mantis
transmission was estimated with an assembly time of ninety-five seconds. Using the current cost of
assembly for a Mantis transmission, provided by Schiller Grounds Care as $14.48, the new transmission
is speculated to incur an assembly cost of $23.00. This value falls within the target value of $25.00 for
assembly ($10.50 above the current value) with some additional room for unseen assembly costs.
Number of Parts
The number of acceptable added parts was set at ten. This was easily calculated for both the
prototype as well as the casted housing by simply comparing the finalized designs to the current tiller
transmission. The prototype had twelve added parts. Although this is above the target value, different
manufacturing processes account for the added parts in the prototype. In the final single-piece housing,
both the linear bearing track and the fork pin posts will be part of the molded final housing. The fork
and “T” will also be manufactured out of a single piece of material which makes the total number of
parts nine, within the target value.
Weight
The target value for the largest acceptable weight addition was set as 5lbs. The prototype was
weighed with a triple beam balance to obtain a weight of 8.25lbs compared to the current transmission
weight of 3.5 lbs, which is an addition of 4.75lbs. The weight of the casted housing model was
estimated using SolidWorks element analysis as 4.98lbs. The additional material in the transmission
housing makes the final model heavier. Although it is within the target value of 5lbs, it is very close. The
design team will have to continue to work with Schiller in order to reduce this weight even further.
Overall not all the target values were met for the prototype due to the limited availability of parts,
machining techniques and time constraints. The proposed casted housing design meets all of the
desired target values, however.
A table comparing the successes of the prototype and the casted housing in each of the metrics
of success is found below.
Table 4: Metrics of success for prototype and proposed casted housing
Metric
Gear housing
Center of gravity
Power output
Cost of parts
Cost of assembly
Number of parts
Weight
Target Value
≤ 3.125in wide
raised ≤ 0.5in
31ft∙lb, 240RPM
≤ $60
≤ $25
raised ≤ 10 parts
raised ≤ 5lb
Prototype Value
2.55in
lowered 0.825in
31ft∙lb, 240RPM
N/A
N/A
+12 parts
+4.75lb
Casted Housing
3.125in
lowered 0.755in
31ft∙lb, 240RPM
$52
$23
+9 parts
+4.98lbs.
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Path Forward
While the prototype was successful, there are several steps that must be taken before the
project can be entirely handed over to Schiller. First, there are several aspects of the design that must
be taken into consideration for changes between the prototype and their final production design.
Single-Piece Transmission Housing
Schiller has a patent on a solid transmission housing, which is very useful for the reliability of
their transmissions. A one-piece housing protects the interior of the transmission from dirt and debris
much better than multi-piece housings and also eliminates shearing in screws due to vibration. The
design team has proposed a solid one-piece housing, but must further work with Schiller to ensure it is
up to their specifications before this model is incorporated into the marketed Mantis.
Worm
Another design modification to be made comes with the worm. Due to time constraints and
material availability, the design team had to manufacture a two-piece worm with a DD shaft lacking
case-hardening. Because of this, no durability or reliability tests could be performed accurately.
However, the team took the care to examine the reactions within the gear train. With the current 5mm
shaft, assuming a worst-case SAE 1050 steel without case hardening, using Tresca failure criterion for
the shear stresses in the shaft, the worm has a factor of safety of approximately 4.7. Although this value
will increase with case hardening as the yield strength increases, this value does not model any impact
loading or vibration fatigue in the housing. Schiller must examine the possibility of increasing the worm
diameter while maintaining the proper 42:1 gear ratio. They must take care to find the balance
between size, weight, and reliability for the marketed product. Additionally, the design team would
suggest to Schiller to examine the possibility of reversing the handedness of the worm and worm gear
and use the upper gear system for the normal tilling output. This would reduce the fatigue felt by the
worm from the longer moment arm experienced in the lower meshed position.
Optimization for Gear Sizing
The design team decided to keep the spur gears at the same diameter, in order to keep the
output the same in both the forward and reverse direction. If Schiller decides at a future point to
increase or decrease the speed or torque of the reverse direction based on requirements for certain
applications, the sizing of these gears can be changed and optimized. The only constraint to the sizing is
that the distance of centers of the two gears is kept at 3in so that the worm gears do not interfere.
Durability Testing
As mentioned earlier, the design team was unable to do any durability or reliability testing
based on time constraints. Schiller will still have to perform extensive durability testing of the new
transmission design in order to stand by the warranties offered for their products. Conducting a string
of long-term tests would allow them to confidently give consumers assurance in their products.
17
Control System
Once the design for the gearing and actuation subsystems is finalized, Schiller must focus on the
control subsystem mentioned earlier. The control subsystem must be designed for the user interface
with the tiller. Although the pin-locking mechanism currently on the prototype is a simple solution to
the problem, it is not aesthetically pleasing. Schiller must spend some effort making their product more
“user-friendly”.
Future Additional Considerations
There are other smaller considerations that must be taken into account before Schiller can
incorporate the new reversing transmission into their Mantis product line. The assembly-line procedure
must be changed. Different pneumatic presses must be designed to accommodate the new bearing
locations and housing size. The assembly order must be modified as well, once the design is finalized.
In addition, before the reversing feature is marketed, Schiller must consider things such as
safety manuals and instruction manuals for both Schiller employees and customers. Such things will
ensure that Schiller makes the most out of their product in a safe and efficient manner.
Acknowledgements
The design team would once again like to thank Schiller Grounds Care for this great opportunity.
Lana and Rick have been instrumental in their engineering advice, guidance, and support. Nina has been
incredibly helpful in securing funds for the team’s design prototype and proof of concept. The design
team has had a wonderful experience working with Schiller on this design and hope that it can be
implemented into their product line in the near future.
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