Rulah, the rover we use for our rugged terrain navigation experiments, had the gears in her motors wear to the point of being unuseable. These were custom-made parts, not sold separatedly, so we had to either replace an otherwise perfectly fine motor or to print our own gears.

We took the following steps:

  • We opened all four motors to find the least-worn gear, and scanned it.

  • We printed the scanned gear in resin, but both the quality of the scan and the printing material proved inadequate and the resin gears were crushed on our first test.

Gear designed in blender

  • We designed new gears in Blender following the instructions in the tutorial "How to Model Geometrically Correct (Involute) Gears in Blender" by Otvinta. The the instructions is detailed and the only tricky bit is getting the distances right so that the gear fits the motors. You see the result in the image above and feel free to use our design as your starting point, if you find it useful.

  • We went through the list of materials and explanations provided in this guide and selected ABS, the most commonly used plastic for automotive parts.

  • We replaced the gears in all motors with our prints, not only the one that was badly worn.

We gave been testing the new gears on rugged terrain for more than a week now, and we see no signs of any problems.