What's new
What's new

What kind of drive is this?

The Dude

Hot Rolled
Joined
Oct 19, 2010
Location
Portland, OR
Can someone tell me what type of drive this is? It functions just like a ball screw but there is some kind of combination friction and maybe gear drive that moves the "ball nut" (that is clamped onto the polished shaft). Seems very precise (behaves like a very fine-pitch ball screw). You can override the "drive" and slide the "ball nut" directly on the shaft.

Thanks
The Dude

IMG_0500.jpg
 
Yeah, thats what they are. Good for inaccurate movement where you need to slip in an overload condition like a plasma cutter height control. Specs say they can be off .002 per turn.
 
Yeah, thats what they are. Good for inaccurate movement where you need to slip in an overload condition like a plasma cutter height control. Specs say they can be off .002 per turn.

Also very good for use in measuring machines where you may want to override the screw for fast manual positioning.

Sometimes "slipping" is good.
Very helpful if you want the machine to slip instead of taking out your $1000 lens or 8 grand probe head when you oops a programming dimension.
Certainly not crash proof, but they do help with low speed "oh craps" as they give the controller time to shut down without hurting things.

As they eliminate the torque change as balls enter and exit the ball tube they are also have a little smoother low speed velocity control than many ballscrews when probing a point yielding better accuracies but you can get around this with very high quality screws.

Measuring machines and machine tools have very different design parameters.
I cringe whenever I see someone wanting to use a machine tool with a probe as an "inspection gauge".
Bob
 
Actually, these don't have a ball tube, just a set of regular ball bearings mounted at a skew angle to the rod.

As the rod spins the block with the bearings on it climbs the rod as the bearings spin.
 
Actually, these don't have a ball tube, just a set of regular ball bearings mounted at a skew angle to the rod.

Yes I know that. My wording was not clear. They eliminate the ball tube which is why they are smoother than ballscrews which do have ball returns tubes (or paths in the nuts). This is only a concern to people working in very,very high accuracy measuring machines and probably does not apply here. :dopeslap:
 
I see these used a lot in the glass industry - a spray bar attached applying coatings as they go between a 20 foot wide row of bottles. They crash all the time without any undue damage to the product or the actuator. And as you noted . . . not too particular about accuracy when you are spraying with a mist.
 
Thanks for all the info guys, I forgot to "subscribe" to this thread so I didn't realize all these replies came in

Much appreciated,
The Dude
 








 
Back
Top