Gear Drives

Gear Drivetransmission of motion or torque from one shaft to another by means of direct contact between toothed wheels or a mechanism consisting of toothed wheels that engage and transmit rotary motion, usually transforming angular velocity and torques.

Gear drive is a rotating machine having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gear drive working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Gear drives can change the speed, torque, and direction of a power source. The most common situation is for a gear to mesh with another gear , however a gear can also mesh with a non-rotating toothed part, called a rack, thereby producing translation instead of rotation.

The gear drives in a transmission are analogous to the wheels in a pulley. An advantage of gear drive is that the teeth of a gear prevent slipping.When two gears of unequal number of teeth are combined a mechanical advantage is produced, with both the rotational speeds and the torques of the two gears differing in a simple relationship. In transmissions which offer multiple gear ratios, such as bicycles and cars, the term gear, as in first gear, refers to a gear ratio rather than an actual physical gear. The term is used to describe similar devices even when gear ratio is continuous rather than discrete, or when the device does not actually contain any gears, as in a continuously variable transmission.

Advanced materials science and higher computing power are driving improvements in all stages of gear drive development and production – leading to significantly smaller gear drive sizes.