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Unread 30-12-2015, 13:22
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Aren Siekmeier Aren Siekmeier is offline
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FRC #2175 (The Fighting Calculators)
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Re: pic: Inverted CIM Gearbox V3

Quote:
Originally Posted by Jared View Post
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.
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