Help: Gear Disengagement

Valid concerns. No answers but some thoughts. Look at how transfer cases in 4x4 vehicles for shift on the fly operate. Most have some sort of method, similar to a manual transmission to sync up the shafts before gears are pushed together. Can you remove the torque off the gear you are trying to move, such that it is just idling on the shaft before you try to move it? If you can idle it on and idle it off, can you not bevel the gears to help with alignment? It may be easier to just move the shaft the gear is on than to slide the gear on the shaft when under load. Are you sure that's not an option? What's the RPM of these gears at the time you want to disengage them?

Thanks Mike, good thoughts! It's actually kind of slow, @ 200 RPM. Also, at the time of disengagement, there should in theory be 0 torque transmitted. I know there will be some torque, and I only said 200 ft- lb because that would be the worst case scenario. During acceleration the torque will probably be around 200ft-lb, but once up to speed, and before disengagement, the inertia of the load should reduce the need for so much torque.

Oh - axial or radial separation would be options - whether sliding them apart along the shaft (gear fixed on shaft) or by increasing the distance between the shafts.

What you're thinking is an absolute disaster. Gear disengagement is always done with some sort of shaft coupling. Gears are never ever ever engaged radially and are rarely engaged axially. The only gears that will work by radial engagement are worm gears but you're still risking high stress concentrations on the teeth. It sounds like you need to let both gears spin each other and freewheel until needed. Meaning, lock one gear on a shaft when needed to transmit power. This was the whole idea of the snychromesh which eliminated de-clutching in automobiles.

wrote:

clutches:

This is a really poor idea. Gears are ratio and direction changes, not for power interruption. Use a clutch; that is what clutches are for. Your idea of disengaging/reengaging the gears to provide clutch action is just looking for trouble.

Dr. D.