pic: 254/968 Gearbox - Destructive Testing Results

[Travis Covington]

Funny you ask. We did do long term accelerated wear and fatigue testing.

We built a total of 16 gearboxes. 4 of them went on competition robots. 254's comp bot saw ~8 hours total run time including practice at 4 events. 968's comp bot saw only ~4 hours run time including practice at 2 events.

However, there were another 4 gearboxes built and used on two practice robots which each saw ~100 hours of driving. After these 100 hours of aggressive use, we saw little to no difference between the practice robot gearboxes and the competition gearboxes with less than 10% of the runtime the practice ones saw. It was determined that the anodize wears initially after 2 or so hours of use and remains at that worn, broken in point for the remaining time.

In addition to those 8, we used 2 more gearboxes on an accelerated wear test platform. We mounted the gearboxes onto a mock side rail and programmed a continuous loop program to cycle the motors and actuate the shifting cylinder: full forward, shift, full reverse, shift, for another 100 hours under load.

Here is a picture of that test platform after the 100 hours of testing. You can see the anodize wear, but after measurement, the involute tooth profile is intact. We also disassembled the gearboxes and checked for any fatigue issues and further damage or wear... while we didn’t have the ability to do a thorough lab test, our brief visual inspection showed no damage or signs for concern.





Also, here is a video showing the test platform with a wheel mounted for later use as a demonstration unit. As shown in the video and pictures, there is no load on the output shaft. This video is strictly to show the cycling procedure used. We may bring this to IRI if people want to see it?

http://sivart.org/misc/Demo%20Gearbox.avi

Lastly, here are the components removed from the test platform after ~100 hours of continuous use. Some wear is noticible, other portions are just dirty from the anodize wear.