What is the primary function of gears in machinery?

The primary function of gears in machinery is to transmit torque and change the direction of force. Gears are designed with teeth that mesh together to create a mechanical advantage; as one gear turns, it imparts motion and force to another gear. This interlocking design allows for the transfer of power from one part of a machine to another, enabling efficient movement.

In many applications, gears can also change the direction of the applied force. For instance, an input gear rotating in one direction can drive an output gear to rotate in the opposite direction. This ability to alter force direction, along with the transmission of torque, is crucial in various mechanisms, from simple clockwork to complex automotive systems.

While other functions of gears may be relevant in specific scenarios—like converting motion or regulating speed—they are secondary to the fundamental roles of torque transmission and directional change, which are intrinsic to the functioning of gear systems.