Vinka mid-drive improvements

[Bokonon]

Hi all, there doesn't seem to be much available on this forum (or others) about the Vinka mid-drives from Japan. A while back I picked up one of the new mid-drives from Wally World thinking it would be an interesting project. These come with a drive that is essentially a Vinka E20. From the factory these bikes come with a 36V battery, rated power of 250W, 80nm of torque, no throttle and a torque sensor.

Taking the drive unit apart (pics below), it appears to have an 88mm inrunner and approx. 60:1 reduction. The rotor shaft has an 8T helical gear carved directly into it. There is a small controller inside the case. No hall sensors.

Ultimately I want more power (a lot of hills here) no torque sensor, running 48V, and a throttle. My first attempt was to hook it up to a VESC. Ultimately I couldn't get the VESC to do much with it sensorless. There was a lot of stuttering, a lot of heat, and not much power even after a few weeks of adjustments.

So I am removing the motor and found this this 87mm, 85KV outrunner drone motor that fits inside the stator case on the non-drive side. This motor should have about twice as much torque as the factory motor. My plan is to add hall sensors and use it with a VESC, but I got stuck on a few things. Any advice appreciated.

1) The drive shaft would need to attach to motor's bell housing, then run through a bearing mounted in the drive case. I'm having a really hard time finding a shaft that will work. The rotor shaft from the factory motor is in the last picture. It is "stepped": 10mm for the gear part, 12mm for the bearing, then a "ribbed" 14mm part that fit into the rotor. I was thinking maybe to grind down the whole thing to 10mm, then use it with a 10mm propeller shaft adapter which are easy to find. Seems like a lot of work. When I search for this type of thing I mainly find "annular cutters"..

2) What's the best way to get the stator out of the metal "cup"? It seems to be pressed in there. I could just start cutting and prying, but there has got to be a better way...

 

[scianiac]

Honestly you would probably be better off getting the VESC to drive the stock motor in terms of complexity. That outrunner will only be more powerful if it's aggressively air cooled and even then may not be. Also you're limited to how much more torque you can add by that nylon gear. You can certainly add more but I kinda think that would limit the torque more than over driving the stock motor. Did you get it to run smoothly with the VESC after the tuning or was it still having sensorless starting issues.


If you wanted to run an outrunner I would select one that has a center shaft which you could press out and then press that shaft in. Something like an 80100 or 8080. Machining would probably be required and would still have the same cooling issues if you want it inside the case.

 

[J. Dub]

Hi all, there doesn't seem to be much available on this forum (or others) about the Vinka mid-drives from Japan. A while back I picked up one of the new mid-drives from Wally World thinking it would be an interesting project. These come with a drive that is essentially a Vinka E20. From the factory these bikes come with a 36V battery, rated power of 250W, 80nm of torque, no throttle and a torque sensor.

Taking the drive unit apart (pics below), it appears to have an 88mm inrunner and approx. 60:1 reduction. The rotor shaft has an 8T helical gear carved directly into it. There is a small controller inside the case. No hall sensors.

Ultimately I want more power (a lot of hills here) no torque sensor, running 48V, and a throttle. My first attempt was to hook it up to a VESC. Ultimately I couldn't get the VESC to do much with it sensorless. There was a lot of stuttering, a lot of heat, and not much power even after a few weeks of adjustments.

So I am removing the motor and found this this 87mm, 85KV outrunner drone motor that fits inside the stator case on the non-drive side. This motor should have about twice as much torque as the factory motor. My plan is to add hall sensors and use it with a VESC, but I got stuck on a few things. Any advice appreciated.

1) The drive shaft would need to attach to motor's bell housing, then run through a bearing mounted in the drive case. I'm having a really hard time finding a shaft that will work. The rotor shaft from the factory motor is in the last picture. It is "stepped": 10mm for the gear part, 12mm for the bearing, then a "ribbed" 14mm part that fit into the rotor. I was thinking maybe to grind down the whole thing to 10mm, then use it with a 10mm propeller shaft adapter which are easy to find. Seems like a lot of work. When I search for this type of thing I mainly find "annular cutters"..

2) What's the best way to get the stator out of the metal "cup"? It seems to be pressed in there. I could just start cutting and prying, but there has got to be a better way...

@Bokonon you should join us hyper mid drive owners on facebook. We are the people you seek

The name of the group is hyper mid-drive owners

 

[J. Dub]

Have you thought about retrofitting the 350 motor by vinka?

 

[Bokonon]

Thank you for the replies. I'll check the facebook group. So far I haven't gotten this project to work well yet. The E350 motor is a promising idea. I reached out to Vinka about this a few weeks back, but the problem (as with most of the mid-drive vendors) is that they are nearly impossible to find retail.

 

[J. Dub]

Thank you for the replies. I'll check the facebook group. So far I haven't gotten this project to work well yet. The E350 motor is a promising idea. I reached out to Vinka about this a few weeks back, but the problem (as with most of the mid-drive vendors) is that they are nearly impossible to find retail.

I too have reached out to Vinka as well asking if our controller can handle the 350w motor E21.