Couplings and accessories

A component that joins two shafts so torque passes from one to the other, while absorbing the small misalignment between them so the bearings are not loaded.

Both are flexible. ROTEX uses a polyurethane spider between two jaws and suits higher speeds and quiet running. HRC uses a rubber element and absorbs shock better. For pumps and electric motors either usually works; the choice comes down to torque and shaft size.

It depends on the load and the environment. Watch for new vibration, a knock on start-up, or rubber crumbs under the coupling. When you see those, change the element. It takes a few minutes and saves a bearing.

The figure you multiply nominal torque by so the coupling is sized for real conditions. Steady loads such as a centrifugal pump take a low factor; shock loads such as a crusher or a piston compressor take a high one.

Where torque is high but space is tight. Two sprockets are joined by a duplex chain and a cover holds the oil. Common on gearboxes and conveyors, but not suited to very high speeds.