Neato Botvac Main Brush Motor Gear

thingiverse

The motor gear on my Neato D7 Connected Botvac came loose and I had to replace it, which was a hassle. After searching online, I found that the replacement cost was way too high for such a small piece of plastic. Most places wanted $40 USD, but I finally found a used motor assembly including the gear, motor, belt, housing, and sensor for just $15 with $5 shipping. Given the expense, I'm not looking forward to buying these gears again if this is a common problem (the original lasted around 9 months). According to the product page, this assembly should fit a Botvac 65, 70e, 75, D75, 80, D80, 85, and D85 models. The comments suggest that it also fits a D3, D5, and D7. I had never worked with OpenSCAD before and decided to take all the measurements and try to model up a spare gear in case the new one came loose again. I set most of the variables via code just in case this part doesn't work out of the box on your printer. I used two libraries while making this part: Polygear by dpellegr, which can be found on Github, and Regular Convex Polygon Library - OpenSCAD by VincentD, which is available here on Thingiverse. I had to increase the center shaft hole diameter a few times before the gear would slip nicely onto the shaft. You might have to go back down if it doesn't work out for you. I measured the shaft on my part at 7mm, but the gear wouldn't fit until I increased the hole to 8mm. The belt seems to fit perfectly around the teeth and connecting the motor to 12v gets it spinning quite vigorously. The hexagon also fits nicely into the replacement brushes I've got. However, I haven't tested the part in a real cleaning cycle yet because I haven't gotten the motivation to take the robot apart again after just getting it back together. Please let me (and others) know if you needed to tweak any of the parameters to make it work with your machine. The top of the hexagon was filled in with some iterations of my print, but clearing the support material from them was difficult. While attempting to do this with a drill, I accidentally discovered that the top of the center shaft was only ~1-2 mm from the end of the part. I removed the top so that the center would no longer need to be cleared and the part still feels strong enough to work. You still need support material around the outside to hold up the belt guard, but it's not too difficult to clear off.