shaftkey

A shaft key is a mechanical component used to connect a rotating machine element, like a gear or pulley, to a shaft. It works by fitting into a keyway, which is a slot on the shaft, and a corresponding keyseat in the hub of the rotating element. This connection prevents relative rotation between the shaft and the element, ensuring that torque can be transmitted effectively.

Keys are typically made from steel and come in various shapes and sizes depending on the application. Common types include square keys, rectangular keys, and Woodruff keys. Square and rectangular keys are often tapered to create a snug fit and provide some axial constraint. Woodruff keys, which are semi-circular, fit into a semi-circular slot on the shaft, making them easier to install and remove.

The primary function of a shaft key is to transmit rotational force. When torque is applied to the shaft, the key transfers this torque to the connected component, allowing it to rotate along with the shaft. In overload situations, the key is designed to fail before the shaft or the connected component, acting as a safety device and preventing more catastrophic damage. The selection of a key size and material depends on the torque to be transmitted, the shaft diameter, and the desired safety factor. Proper installation and maintenance of shaft keys are crucial for the reliable operation of machinery.