Alternatives to Keyways in Motion Systems

The age-old tradition of using shaft keys in mechanical drives has served the power transmission industry well for many years. When appropriately sized, it guarantees that virtually no relative motion can take place between a shaft and its respective shaft hub in a unidirectional continuous motion application. Today’s increasing demands for speed, precision, and small size have changed the standard for shaft locking devices, and challenged motion components manufacturers to develop new methods of keyless shaft locking for dynamic loading. As motors and drives become increasingly capable of rapid acceleration and rotary positioning accuracy in smaller and smaller packages, backlash, stress distribution, and balance have all needed to be addressed in shaft locking devices, in many cases rendering the shaft key obsolete.