CIM motor and 8mm key hub

Our team is looking at using andy mark gear to launch the disks. Namely, using the large CIM motors and pneumatic wheels connected using an 8mm key hub. With the wheel sitting on top of the motor, the key hub rests on the face of the motor. To me this seems far from desirable. How have other teams attached their CIM motors to the pneumatic wheels?

Which ever method you use, please be reminded no motor likes to see a bending load on its shaft. this means no direct placement onto the cim motors keyed shaft. Look into a small reduction gearbox of some type that suits your design criteria or do your best to support the final output shaft through the use of bearings or bushings.
Hope this helps. Many motors fail “unexpectedly” when loaded directly either in competition or on bench testing.

One of our prototypes that is similar to yours has a “cage” over the wheels. From there two dead axle/bearings set ups drop down into the wheels to help support any lateral movement of wheels on the output shaft of the CIM.

you could cut 3/8" off the boss on it and clamp the hub on with a 8mm shaft collar.

Hi Phyrxes. Our working design included a cage (still a build in progress) with a bolt dropping down into a bearing in the top of the wheel. Hopefully this would prevent bending. What I wasn’t sure about was if I should have this bolt floating inside the wheel, or if I should turn it around and have it supporting the weight of the wheel. Supporting the wheel would then prevent the hub from contacting the motor… either way I still think I would prefer a dead axle extending all the way through and drive the motor using a belt… any other thoughts?

The first generation prototype had a spacer between the hub and motor, our second generation (currently being fabricated) has the motor above the wheel.

I did have the the thought of putting the motor above the wheel. I’ll need to sit down and think about this more. There seems to be a lot of assumptions in other threads about what the CIM motors can and can’t do wrt to radial load, high current draws and use with and without gear boxes. It makes it very difficult to know how we should or should not be using the motors.

We aren’t running ours at full speed, as a number of people have posted video running a slight speed difference between the wheels and still only about 50% input was getting 30 ft shots.