Ball Bearing Mech. Coupling

[mtipg]

I am looking at a unique application where I am planning on using ball bearings to transmit torque between two mating shafts. I have uploaded a picture of the general idea. (Forgive me the picture was done quickly with paint.) There is only one ball in the picture but this will be copied several times around the shaft in a circular pattern. Also, the reason for this design is to transmit torque while allowing the "beige" outer shaft to move freely along its its own axis.

My question is two fold.

1. Has anyone dealt with an application that is similar to this? Would you mind sharing your experience?

2. Would this best be considered at a spherical keyway of sorts, when measuring torque capacity?

 

[MintJulep]

It won't work - except maybe for very low torques.

It will lock itself tight against axial movement when torque is applied.

Google "overrunning clutch" to understand why.

 

[GregLocock]

That's roughly how an Rzeppa CV joint works, as modified to allow axial plunge. As MJ says, they don't really plunge very well while they are loaded up, to do that properly you need a Tripod CV joint. I know you don't need the angular articulatuion for this application.

If you really want to guarantee that the thing will plunge when loaded consider just using a spider between the two shafts.

Splines don't easily plunge under load either.







Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[MintJulep]

Except that in the CV the radial loads are supported by the cage, not the balls.

 

[GregLocock]

Well I never knew that! Good one.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[alansimpson]

Following looks similar:

https://sdp-si.com/eStore/Direct.asp?GroupID=844

 

[Tmoose]

Looks like a basic ball spline. If the axial travel forces the balls to the end of the slot, then to avoid jamming they need to recirculate, like this.

http://news.thomasnet.com/images/large/492/492789.jpg

Assembling it so that the balls start in the middle of the travel might be tricky.

 

[mtipg]

Thanks so much for all your inputs!

Tmoose, The ball spline looks like exactly what I want to do, I didn't realize there was so much info on it, I guess you just need to get the right vocabulary and google then tends to be a big help.

Cheers!