Project: Pangea (smushing two 9C together to make one motor)

denito

1 mW
Joined
Apr 10, 2010
Messages
16
Back in 2010-2011 I picked up a bunch of 6x10 9C hub motors when an ebike site was doing a 5 motors for $400 close out sale. I wanted to use them to make a 4 wheel electric bicycle car. However a three wheel vehicle would be much easier to fit into the vehicle classification laws in my state.

I'm wanting to build something with a configuration like a Morgan 3 wheeler. Of course now that Morgan actually came out with an electric version it is less original to do mine, but then again I can't afford it anyway. I'm going for something more than a bicycle (moped class? Experimental car?) that I can use to make my 11 mile commute to work.

Since I already had a 6x10 9c rear hub motor that makes six motors. What if two motors powered each single wheel of a trike? The cheese version of this would be thread the solid sides of the axles into 3" sections of water pipe and lace the wheels between the two inner rims. However a better way would be to really join the cases. (and the easiest way of all would be to just run two unmodified wheels in a pod, but then I'd need 6 controllers; with mechanically joined wheels I could wire them as one motor.)

I'm planning to run the highest voltage that the wire insulation will support. Since this is a larger vehicle, I am not limited by the battery size for series cells, and with so many motors it makes sense to up the voltage and reduce current. That's why I wanted the 6x10s.

If the cases are joined air tight and the axles have holes on both sides, that opens up a neat possibility: run inlet and outlet port (bath the wires) through the axle for ATF to cool the motors. Solid fill no air, and run all 6 motors to a small radiator.

Only problem is, while I have general idea what is inside these motors (mechanically) I'm not sure what and how and where to cut them to join them up. That's why I'm posting here to ask for help and advice.
 
There is no real need to hack them up. You just need a way to weld them onto a single shaft and give each motor its own controller. Advantage is that you can use cheap controller and still get lots of power. The cheapest "barn welding" solution would be to make a square with a bar in the middle and have each motor run on their own axle inside each rectangle and use that as a single wheel. Basically a variant of double air on trucks. Then you can put 4 motors on the back wheels. If the wheels are close enough they are viewed as a single axle/wheel keeping the 3 wheeler legal stuff.
 
flippy said:
There is no real need to hack them up. You just need a way to weld them onto a single shaft and give each motor its own controller. Advantage is that you can use cheap controller and still get lots of power. The cheapest "barn welding" solution would be to make a square with a bar in the middle and have each motor run on their own axle inside each rectangle and use that as a single wheel. Basically a variant of double air on trucks. Then you can put 4 motors on the back wheels. If the wheels are close enough they are viewed as a single axle/wheel keeping the 3 wheeler legal stuff.

I like this. It also allows me to use the wheels and tires already fitted to the hubs. Could also make something that looks like airplane landing gear with the load bearing shaft between the wheels. With the strut ending in a bearing with a big hole, the outside and inside joining of the wheels could even be concentric tubes passing through the inside of that bearing.
 
You don't want a bearing on the central strut, becuase you need to secure the axle flats to it, so the motor can push against the frame to create torque to push you along the road. You'll also want ot secure the axle flats on the outer ends to the frame holding the wheels on, too.

All the bearings are in the actual wheels.

So you wouldn't want a tube in between teh wheels, but rather a form of clamp securing them to the frame. It could be as simple as a literal clamp (or block, as Flippy described) as wide as however much you choose to leave of the axle lengths, so ti clamps over the entire lenght of axle flats on both axles where they meet.


Regarding the lacing to the mtoors, you could either interleave spokes from each hub to the rim for a single central rim, or you could use two independent rims, one on each hub, and run "duallies" to provide redundancy in case of flats, and to increase traction and braking power (more contact patch surface area).

If they are independent, then you could even take each motor/wheel off separately, to do tire changes or other maintenance.


All that said, if you did want to hack them up and rewind them, Farfle has a thread doing just that with a pair of Magic Pie motors, IIRC, several years ago.


You could avoid the rewinding step by making a tube that connects the spoke flanges together, and leaves off the covers on the sides that face eachother, andthen make a custom axle going thru both stators, perhaps a hollow one (like Farfle did) to run the phase and hall wires thru.

SInce the hubs would be locked together, you could just parallel the phase wires, and use only one set of halls, and use just one bigger controller for both motors.

But it's a lot of work for likely no real difference vs leaving the motors as-is and just using htem side-by-side as duallies. :)

I don't recall which thread it's in, but there is a commercial scooter (or mc?) motor that does pretty much exactly what I just described, though whether they did that for performance gain or just because they could (and had parts laying around thta would work), I don't know.



Regarding full-ATF fill, that's gonna be really messy, as it will leak out both thru the wire cabling (via the actual conductors inside the insulation if not between the wires), and thru the bearings and the space between bearing and axle and bearing and cover (cuz it's never a perfect fit), as well as the edges of teh side covers where they meet the rotor flange.

I think it's Linukas here on ES that has made a cooling system that uses tubes inside the stator against the windings/teeth that exits the motor to a radiative system. That'd be more practical, as leaks are probably easier to prevent.
 
Yup I think dualies are the way to go; worth it for the flat tire redundancy alone.

You know, if I offset the axles on the central strut, I could get the wheels closer, and have a narrower and simpler strut with two holes.

I haven't decided yet whether the central strut will be holding the wheels single ended (like the two wheels on a medium large airplane nose wheel) or of I'll need 3 struts per wheel. The standard advice I remember reading 6 years ago was that attaching trike wheels on just one side risks breaking the axles, but in this case the load would be nearly half because it is shared. A central strut might allow 3 wheel steering toon
 
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