Disk (Woodruff) Keys

Woodruff keys are commonly used, similar to parallel keys, to fix the position of shaft and hub in tapered connections. This form-fit connection enables torque transmission, for example from a drive shaft to a gear. Woodruff keys are also referred to as Woodruff keys in English terminology.

The Woodruff key transmits torque via its side flanks through a positive-fit connection. It acts as a torque driver, transferring torque from the shaft to the driven component (e.g. drive shaft), or from the driving component to the output shaft. In axial direction, the wheel is typically secured against displacement on the (usually tapered) shaft using a locknut.

Woodruff keys are standardized in shape and dimensions according to DIN 6888. According to DIN 7155, the keyway width is usually toleranced with a P9 fit for a tight fit or N9 fit for a looser fit. The key width corresponds to a h9 tolerance (lower deviation = 0), while the key height is toleranced to h12. Design and calculation guidelines for key connections are specified in DIN 6892.