'Ball screw' type worm & worm wheel drive

[gearcutter]

Interesting video showing a 'ball screw' type worm & worm wheel drive.
I wonder what sort of loses there'd be and how smooth the engagement would be.

http://youtu.be/hvz9A0c_HeQ

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[MikeHalloran]

His worm wheel has grossly enlarged entry slots, suggesting that maybe the fine points of geometry have not quite been worked out.

I can't help but think that I've seen it done before, and better, as in a double-cone double-enveloping worm.

I'd expect the efficiency to be similar to that of a ballscrew assembly, if the geometry is right.

Mike Halloran
Pembroke Pines, FL, USA

 

[gearcutter]

The mechanism is very crude but it's an interesting idea.

It looks like the diameter of the cutter that he used for the gear's profile was too large, much larger than the worm's diameter anyway.
I'd imagine the generating tool for the gear's profile would look like something similar to a profile used for cutting roller chain sprockets.

He has other videos showing a double enveloping design.


Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[tbuelna]

While it's difficult to tell from the video, unless there is true rolling contact between the screw flanks, the balls, and the gear flanks, then this concept will likely not be much more efficient than a conventional worm gear drive. Not to mention the fact that it would have much lower torque capacity for the same volume.

Recirculating ball screws work acceptably because the ball and race contacts produce very little skidding. The approach and recess motion of the race surfaces of the gear makes for a much more complex contact geometry than ball screw threads do.