Woodruffnøkkel

Woodruffnøkkel, also known as a Woodruff key, is a semicircular key used to transmit torque between a shaft and a hub. It is named after William Woodruff, who patented the design in the mid-19th century. Unlike standard parallel keys, Woodruff keys are designed to fit into a semicircular slot milled into the shaft. This allows for easier assembly and disassembly, as the key does not need to be pressed in with significant force. The semicircular shape also helps to prevent the key from being dislodged due to vibration or axial movement.

The primary function of a Woodruff key is to prevent relative rotation between two components. When torque is applied, the key engages with the corresponding keyway in both the shaft and the hub, effectively locking them together. This is crucial in many mechanical applications where precise alignment and power transmission are required. Examples include automotive components like crankshafts and pulleys, agricultural machinery, and various industrial equipment.

The advantage of a Woodruff key lies in its self-aligning nature and the fact that it only requires a semicircular slot in the shaft, which can be easily milled. This simplifies machining compared to the rectangular keyways required for standard keys. However, the deeper slot in the shaft can potentially weaken it, which is a consideration in high-stress applications. The key itself is typically made of steel and is available in various standard sizes to suit different shaft diameters and torque requirements.