torque mounts

This torque mount scheme was used to mount the servo's to the
ballscrews directly on the Cincinatti Cintimatic that I removed the
ballscrews from about a year back. The motors had only a solid coupling
between the shaft and themselves. Interestingly, the motor bearing was the
only bearing for that end of the ballscrew! The screw was rigidly
constrained (two tapers back to back) on the opposite end, and only
constrained by the motor's bearing, and the torque mount, on the drive end.
By this I mean that the screw had no support on the motor end, other than
the motor itself, which was mounted most like the torque mount method. It
did not have a double ended shaft and bearing, but was just prevented from
twisting, and not as rigidly held in the radial direction, (although it was
not free either).
The total ballscrew suport was a rigid mount on one end, a fairly
massive ballnut mount on the table, and the motor's rigid coupling.

Brad

> From: Greg Jackson <jackson@...>
>Subject: torque mounts (was Re: Helical Couplings)

>Torque mounts are definitely underutilized in industry. So many engineers
>see the nice little 4 bolt flange and assume they will rigid bolt it in
>place, and then engineer all sorts of Rube Goldberg things to get the
>alignment right.

>Fact of the matter is that all most motors are good for is torque and that
>the best way to mount them is often a torque mount. This works really well
>if you happen to have a double shaft motor. Just use a solid coupling to
>the shaft you need to drive, then mount a bearing on the back side of the
>motor. The motor itself then floats between two bearings. All you need do
>is to bolt an arm to the motor housing and fix it with a single point
>contact. In effect, all you are doing is delivering a solid base for the
>field winding to work from. The rotor is fixed to the shaft. Alignment
>and self aligning couplings are never a problem with a torque mount.

>G. Jackson