Tips for understanding torque with bellows and Oldham couplings

It’s important to note the difference between steady state and max torque based on motion type or when using a bellows vs. a disc coupling. It’s also important to understand how couplings are rated. Jaw couplings have a peak torque, for example, and rigid couplings have a superior torque capability but do not allow for misalignment.

“If you look at our couplings ratings you’ll see a static torque rating and then the note that says ‘for single direction application divide the static torque by 2, and if you are reversing divide the static torque by 4.’ These are your design numbers that you need to use when your picking your coupling,” says Ruland Manufacturing VP of Sales Robert Watkins.

With certain types of couplings, whether its reversing or single direction, it doesn’t affect the torque capacity. Oldham couplings are just one example, jaw couplings also. On the Oldham’s and jaws the engineer will see what’s sometimes called a rated torque. Here, the user does not have to use a formula of divide 2 or divide by 4. These designs of couplings, the oldham and the jaws, are rated the same for reversing or single direction.

Ruland
www.ruland.com