0

I am building a 4 wheel drive rover robot. I was very lucky to find four good condition wheel chair motors on the side of the road. I had to disassemble the wheel chairs of course but well worth the effort.

enter image description here

I also have 4 John Deere riding mower tires similar to these:

enter image description here

they are the same size however the ones I have already have a keyway in them. You'll notice of course that they have no mounting holes in their hubs.

My solution to this problem is as follows:

  1. Mount a pillow block bearing on the outside of the body of the robot
  2. Mount another pillow block bearing on the inside, but facing backwards.
  3. Bolt a piece of steel that is the same size as the inside pillow block frame
  4. Bolt the motor's default mounting to the piece of steel.

Another option of course is drilling holes into the hub of the tires I have, but I am concerned about ruining the tires while doing so

These are the solutions based on the tools and skills I have. I don't know how to create a CAD drawing and have it 3D printed, or CNC machined online.

The upfront time investment in learning CAD just to design this piece makes it less practical than using the tooling and experience I already have.

My questions are: what are you thoughts on this idea? How would you go about connecting these two for a rover robot.

Michael Harvey
  • 105
  • 4
Sam Hammamy
  • 147
  • 6
  • I suggest that you upload the images into your post. Not many readers are going to follow two links just to understand what you are asking. – Transistor Jun 12 '22 at 09:17
  • Those wheels are designed to freely rotate on their bearings. How do you expect to get drive? – Solar Mike Jun 12 '22 at 09:48
  • Does this answer your question? [Torque Problems vs Motor Problem?](https://engineering.stackexchange.com/questions/51302/torque-problems-vs-motor-problem) – Solar Mike Jun 12 '22 at 09:53
  • Thanks @SolarMike, however the reason for this question is that I want to change the design of the rover from a motor with gears/chain, to a direct drive motor using an already geared motor. Therefore I believe they are different questions. Similarly I should have added that the tires I have already have a keyway in them, and the axles I am using already have a keyway as well – Sam Hammamy Jun 12 '22 at 12:19
  • No keyway shown in those bearings. – Solar Mike Jun 12 '22 at 12:29
  • did you check if the wheelchair was stolen? ... thieves may have dumped it – jsotola Jun 13 '22 at 03:04
  • @jsotola that's a terrible thing to assume! The owner of the two wheel chairs who had them on his front yard, helped me load them into his van since I don't have a truck. He is a disabled person and was kind enough to help me. It took two trips! – Sam Hammamy Jun 13 '22 at 11:46

1 Answers1

2

Assuming I'm understanding your solution correctly that sounds decent, and it may be necessary if the wheelchair motors don't have bearings large enough to take the full load of the wheel. You will probably want a spider coupler, or a belt between the wheel shaft and the wheelchair motor to handle any misalignment. Soft mounting the motors might also work.

If the wheelchair motors DO have strong enough bearings, you could make an aluminum adapter that attaches the motor flange to the hub. I would turn it on a lathe or 3D print it (you're probably going to want to learn it sometime). Basically make one side of it conform to the hub shape, and attach it with bolts, (or 1 large bolt through the shaft hole). The other face would have a hole pattern that matches the motor.

Drew
  • 1,848
  • 7
  • 18