How bad would it be to use a dog gear as a brake?

Technical Technical Discussion
1

So in a completely hypothetical discussion, the idea of removing the inner coupling gear on a WCP DS gearbox and replacing it with a machined piece of aluminum that is fixed to the motor plate of the gearbox to bind with the dog gear to use as a brake came up. Of course, we wouldn’t use this to stop the robot in motion, it would only be used once the robot has already stopped to prevent the wheels from spinning.

Is this an awful idea? What other successful methods for locking the wheels other than the obvious disc brake have you seen?

2

Assuming you’re using this for a hanger, I don’t forsee you shearing teeth of a dog gear. That being said, since you’re transferring all the force to your gearbox plate, ensure that neither the gearbox plate or the mounting interface between your gearbox and frame will break.

EDIT: The screw/pin holding the dog gear to the inner shifting shaft would also be of concern.

3

You might have trouble disengaging it under load if the external load (another robot pushing) isn’t removed.

4

Idk, looks like it works pretty well if done properly

5

The robot would have to be stopped or going slow for this to work but you could have downward facing cylinders ram a wedge between the wheels :o

6

This is the idea. The other idea I had was to use a disc brake disc brake with a mechanical caliper, but the dog gear solution would be a lot simpler and more compact.

7

Closed loop control on drive would work well

8

This is the idea. The other idea I had was to use a disc brake disc brake with a mechanical caliper, but the dog gear solution would be a lot simpler and more compact

I can confirm that this will happen, and you probably dont want it to. In 2014 we used a dog gear to disengage a ratchet which prevented backdrive of our shooter winch. The dog would get stuck in normal operation, and needed to be pulsed forwards each shot to eliminate the frictional force preventing disengagement. This isnt as easy to do with a drivetrain. The dog will hold you still no problem, but you may be stuck that way if you’re not careful.

I saw a lot of incredibly simple friction brakes on elevators last year (basically just pistons with traction material on the tip forced against a moving part), and a similar system would avoid this problem.