VersaPlanetary Friction Clutch
 

VexPro/WCP's new 775pro is wildly cool. However, packing 143W into the 775 form factor seems to have come at a price, namely the allowable stall time. According to Vex's data, the 775pro burns up after ~3.9s of stall at 12V, which is faster than the other FRC legal 775 form factor motors.

One approach to avoiding stalls is a torque-limiting clutch. I designed a clutch that replaces a single stage of VersaPlanetary gearing and helps to mitigate stalls in theory. It uses a neodymium magnet and two aluminum friction plates to transmit torque through a friction interface that is sealed off from the rest of the gearbox using an O-Ring.

This design has not been verified using anything other than some back-of-envelope calculations involving the clamping force of the magnet and the friction coefficients of the plates, but should be an okay starting point for anyone deciding they want this functionality.

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"Pack and Go"ed Assembly

Rough BOM:
1 x 10:1 VersaPlanetary Ring Gear Kit
1 x 3/4"ODx1/4"IDx1/4"TH Ring Magnet, axially polarized, such as this
1 x Dash 123 O-Ring
1 x Custom cast Transmitting Plate
1 x Custom cast Recieving Plate