Ring-A-Majig Contest 2016

Robot Torsen Differential

Dr. Ranjeet AgarwalaEast Carolina University

Department of Technology Systems

Created in Autodesk Inventor/Fusion 360 By

Joshua StevensAndrew DiMeglio

Connor Jones

3/31/2016

IntroductionOur team’s entry in the 2016 Rotor Clip “Ring-A-Majig” contest is a Robot Torsen

Differential which uses a variety of eight different rotor clips in assembly. In total, 43 rings were used to assemble the differential and its counterparts. Throughout the project our team members used our 3D modeling/CAD experience to create a model comprised of 32 unique parts and 123 pieces total (including the rotor clips). The model names/sizes of the clips used are listed below:

TX-50 BSH-62 BSH-31 VSH-100 SHI-100 SHR-39 SHR-62 SH-15

Creation and Application There was a lot of teamwork and critical thinking involved to split the work up evenly

and accomplish our goal on time. Our 3D model was created entirely from scratch using Autodesk Inventor and Autodesk Fusion 360 modeling software. We watched a video of a torsen differential functioning to get an understanding of how the system works, and then created the raw gear system. The next step was to create casings for both the worm/spur gear system and the differential as a whole which keeps the differential working properly while keeping it safe from the environment. Rod sizes and clip sizes can be scaled up or down to fit a number of applications with two axles. Using the rotor clips as opposed to nuts, bolts, screws, etc., our assembly can be created as a kit to be used for schools or in homes unlike traditional manufacturing methods which use heating/cooling methods to fuse the gears and rods together. This leads us to believe that this method of production and assembly would save both time and money for the manufacturer as well as opening up the versatility and usability of the assembly. Assembly views (without the top casing, to show detail) are pictured below in figures 1 and 2. Some components have had their opacity reduced to further show detail.

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Figure 1 – Southwest Isometric View of the Full Assembly

Figure 2 – Northwest Isometric View of the Full Assembly

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Differential DescriptionTorsen (a type of limited-slip differential) differentials are used in place of standard

differentials which are used on all vehicles with an axel and two wheels. A torsen differential is used in situations where a wheel would slip (be it on ice, mud, etc.). When a wheel starts to slip or whenever a wheel loses contact with the ground, the wheel continues to spin and the system does not give adequate power to the wheel that is still in contact with the ground. Using a torsen differential in this scenario allows the wheels to spin independently giving the power, which would otherwise be wasted on the slipping wheel, to the wheel making contact to aid in continuing movement. The bare differential with rotor clips is displayed below in figures 3 and 4.

Figure 3 – Southwest Isometric View of the Differential

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Figure 4 – Northwest Isometric View of the Differential

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Rotor Clip ApplicationsBelow is a list of the model names and sizes of the rotor clips used, followed by the number of clips used in the assembly. Pictures are supplied to describe the placement of the rings. Some components of the model have been removed or pictured with reduced opacity for better description.

TX-50 (2 used)

Figure 5

The self locking TX rings (pictured orange) were used on the exterior of the wheels (part number 3) and drive rod shafts (part numbers 7 and 8) due to their greater thrust load capacity, securing the wheels during high loads when turning. The teeth on the ring give a strong connection while allowing for easy removal to change wheels.

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BSH-62 (5 used)

Figure 6

Each of the 5 BSH-62 rings (pictured orange) was used on one of the five bearings. The bearings are created by another distributor. It is important to make sure the drive rod shaft (parts 7 and 8), the bearings (part number 5), the cap (parts 1 and 2) and the gear box holder (part number 4) are all snug together. The BSH rings allow for adjustments due to different tolerances created by the distributor of the bearings.

SH-15 (6 used)

Figure 7

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Figure 8

SH rings (colored yellow in figure 7, and silver in figure 8) were used to fasten the gear holding rods (part number 19) to the bevel gear’s exterior (part number 13) and the gear box plate exterior (part number 20). The SH was used because of their availability in small sizes.

VSH-100 (1 used)

Figure 9

The VSH-100 ring (pictured blue) was used to fasten the main drive shaft and small bevel gear (part numbers 6 and 30) together. The 15 groove on the inner edge helps secure the gear to the shaft, eliminating its ability to wiggle around causing misalignment of the bevel gear and small bevel gear (part numbers 13 and 30).

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SHI-100 (1 used)

Figure 10

On the other side, the main drive shaft and small bevel gear are held together by the SHI-100 ring (pictured green). The main drive shaft was chosen to be modified from .5” to 1” in diameter to be able to incorporate a beveled ring into our design. The fasten the main drive shaft and small bevel gear we needed to use the inverted SH ring so there would be enough clearance in between gears and the cap.

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BSH-31 (12 used)

Figure 11

12 rings in total were used to fasten the spur gear rods (part number 31) to the gear box holder. Four of the yellow rings are pictured in figure 11, while the other eight are positioned every 120 around the gear box. Like the other BSH rings, they allow for any tolerance differences in the manufactured parts while keeping the components securely fastened.

SHR-62 (4 used)

Figure 12

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Figure 13

Figure 14

Just like the SH, the SHR rings (pictured in yellow) have a groove on the inside to help with securing the sun gears (part number 12) to the drive rods (parts 8 and 9). The SHR model is thicker, therefore able to withstand stronger forces. This is extremely important for the main drive shaft with all of the forces going on. One ring was used on each side of the two sun gears for a total of four.

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SHR-39 (12 used)

Figure 14

Figure 15

All 12 SHR-39s play a very important role in our assembly. They are responsible for holding the entire cap housing together (parts 1 and 2) and keeping it together so it can stay clean and free of debris. SHRs were used again for their durability and thickness. They can be seen in figures 14 and 15, pictured in silver attached to the green and yellow rods (part number 9) with added O-rings to help keep the housing together.

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