×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Ball Bearing Mech. Coupling

Ball Bearing Mech. Coupling

Ball Bearing Mech. Coupling

(OP)
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?

RE: Ball Bearing Mech. Coupling

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.  

RE: Ball Bearing Mech. Coupling

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

SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: Ball Bearing Mech. Coupling

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

 

RE: Ball Bearing Mech. Coupling

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.

RE: Ball Bearing Mech. Coupling

(OP)
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!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources