pic: Inverted CIM Gearbox V3

[Aren Siekmeier]

Originally Posted by Jared

Three CIMs have a combined stall torque of around 1000 in-oz, and pinions have a pitch radius of around .3 inches, so the tangential force at the pitch circle is around 3000 oz or 190 lbs force. FRC gears have a pressure angle of 14.5 degrees, so the radial load is 190 x tan 14.5, which is 50 lbs.

50 lbs is less than a cantilevered wheel will experience on a WCD and these shafts do not commonly bend.

I am more worried about the ~25 in-lb torque on the bearing (gear cantilevered .5" from the bearing). It appears there is not a second bearing to fix this, but I haven't loaded up the CAD so I could be wrong. Perhaps one solution is to rigidly mount the shaft to the gearbox plate and run one of vexpro's bearing bore gears directly on a bearing, so that the gear is centered on the bearing.