Roomba Herringbone quiet gear set

thingiverse

Roomba 5 series green CHM quiet replacement gear set for cleaning head module, note: different Roomba models use distinct gears. Aug 13 2019: I added a filet and chamfer to the brush and beater gears to enhance print strength. Print these parts closely or at 100% infill. After 300 hours of vacuuming abuse in my shop, cleaning up metal bits, the beater shaft finally sheared off due to excessive wear. Failure analysis revealed the printer's slicer has a reduced infill in thin wall sections. Conclusion: I need a different slicer. Herringbone involute tooth profile with zero backlash for smooth operation. This gear set is designed for vic7767 ball bearing hair reduction modification circa 2009 (http://www.robotreviews.com/chat/viewtopic.php?f=1&t=11591). The transmission has 6 gears, two of which are identical. I included only 5 files; you need to double print roombaherringR.stl. The three idler gears (roombaherringR.stl, roombaherringL.stl, and roombaherringR.stl) are installed with the smaller and deeper circular depression facing forward. The axle hole is slightly undersized. Holes need to be straight and have minimal shaft clearance. Carefully run a drill through the axle holes. Gears can be tricky to install due to their herringbone profile with zero backlash. You need to engage all gears and slide them down the shafts simultaneously or fiddle with them while trying not to drop them off the shaft if attempting one at a time. Grease only the axles and run them in for 10 minutes or until gear surface finish improves, then grease the gear faces. If you have an adjustable bench power supply, run in the gears with the transmission cover open because the herringbone profile tends to track the motor-mounted gear position. In the photo of the closed transmission, I put tape over the shaft bushings as an additional mod that keeps the grease in and hair out, but it is not required. Have fun, Peter