I have been developing this new motormount for a while(1-2 months) and i decided to make a topic about it.
What has been done?
Truck adaptor plate, fits trampa cnc machined trucks.
Motor baseplate, designed for 63mm motors with 44mm bolt division.
Spur gears designed and ordered.
Stress analysis for mechanical parts.
3D printed prototypes(Alot).
Designed magnetic encoder.
Cost optimization for parts.
Design cover with integrated encoder.
To Do :
Finish magnetic encoder design and order.
Finish baseplate, truck adaptor design and order them cnc machined.
Design wheel adaptor and 3D print it.
Machine spur gears.
March 3, 2021, 7:57am
Great work so far!
So do you need a magnet on the motor shaft?
Yes. I have tried attaching 3d printed “magnet holder” on the shaft. That worked fine, but i think it could be more compact. For this i am trying to embed magnet inside the spur gear so i could save 3-5 mm of cover height.
March 3, 2021, 8:25am
What is the advantage of encoder compared with hall sensor inside the motors?
Normal esk8 motor has 7 pole pairs and 3 hall sensors, so it generates 42 pulses per revolution.
42 pulses / 360 degrees. 1 pulse equals ~8.57 degrees of resolution.
Encoder generates 4000 pulses / revolution ( 4000 pulses / 360 degrees), which equals 1 pulse / 0.09 degrees of resolution.
Higher resolution is important for FOC mode.
Increasing resolution, increases dramatically low speed torque and efficiency of motor, removes coqqing.
March 4, 2021, 5:54am
Are the gears steel or not steel?
Wheel spur gear is made of POM plastic and spur gear on the motor shaft is steel. It’s pretty common to use soft and hard material in drivetrain.
Interesting design, I don’t think I’ve seen anyone with encoder integration quite yet.
Mountainboards and encoders mix really well, and I agree, I think embedding it in the spur gear is a good idea. Need some kind of retention though so it doesn’t break off and get in the gear teeth
That’s good point to make sure magnet can’t get in the gear teeth.
March 4, 2021, 8:59am
Do you have any plans to use steel gears in the future?
March 4, 2021, 9:04am
Etoxx approximately 5 years ago. Ready available since years.
It’s possible. I am making wheel gear assembly modular so material of teeths can be changed.
Encoder wire is attached to cover plate. I designed there 1 zip tie, but i think i go for 2 zip ties just to be sure.
Motor attached, motor shaft will be cutted correct length.
Spur gears arrived :
Encoders arrived :
I got cnc and have been learning to use it
3D printed bracket for milling
Finally its working
I made 10S6P Samsung 30Q batterypack for this project.
Vesc is limiting peak power to 3200 watts. Thanks to encoders torque is very high and constant.