Ebike friction drive unit

thingiverse

Update 24.03.2019 Now as the weather is getting better I had a chance to test the e-drive in real.This this thing accelerates as hell with a 4S battery and the motor and the ESC is good for 6S. The test reult is that the position of the drive unit to the wheel is very important , if it is too high than it can jump over as the tires got pressed. To prevent this an end stop will be needed. Probably a small (RC car size) shock absorber is also a good option. The gear mesh is good and the gears are strong enough for this motor. This is work in progress, at the moment only a proof of concept only the 2. sprint of the project. This thing is a drive unit to convert a mountain bike to ebike. Design goal is to make a fully 3D printable drive unit what can be fitted to a mountain bike in limited space. The unit shall not serve for long rides but only as a booster on a few slopes. The bike I use for testing is an old 26" woman bike. The unit is using RC hobby electronics what are available from many manufacturers in similar size and quality. A short video of the unit https://youtu.be/5WURZFLKVwA The friction drive is self locking in one direction and freewheeling in the other direction only by it's position to the wheel and the direction of rotation. No additional pressure needed to push the drive gear to the wheel, no oneway bearing is used. At high speed oscillations are generated because of the irregular circle form of the bike wheel. I will need a shock absorber inbetween the console and the drive unit. I plan to use some RC car shock unit in version 3. The ESC is controlled only with a potentiometer (servo tester attached to the handlebar) currently I have no resources to develop a better solution. The battery is only temporary, a Battery box will come. Cable management is also a next step. Motor: Hobbyking Turnigy Aerodrive SK3 4240 620KV ESC: Hobbyking Redbrick 60A Battery: LIPO 4S with as much capacity as you can get. Probably I will try a 6S if I get one. The motor and ESC can handle it.