For everyone who was curious about the strength of the gearbox components, we had a third party testing laboratory verify strengths as part of the final analysis for our senior project.
Some results to note:
- 170 foot pounds of torque before failure on the output shaft. That’s the equivalent of a higher powered 4 cylinder engine you’d find in your car!
-4,119 pounds bending force before failure on the output shaft. Again, very high and quite unexpected!
-155 foot pounds of torque on the 80 tooth gears web before the test rig failed! The gear was intact with no noticeable deformation!
Also, if you look closely at the components, you can see clear examples of the inherent stress risers caused by sharp corners. Almost all of the shafts failed where there is a sharp corner. This was avoided as much as possible, but without specialized tooling, elimination of these sharp corners was difficult. For our purposes it was not completely necessary either, as almost all components had factors of safety well above what a FIRST robot needs.
Feel free to ask any questions.