This fundamental mechanical component transfers rotational power and motion from one shaft to another. When paired in a mesh, the relative size of each rotating element determines the mechanical advantage and speed ratio of the system. While often used interchangeably with the general term for a toothed drive component, engineers typically use this phrase to distinguish the larger driven element from the smaller driving pinion.
The inspection report shows heavy pitting on the gear wheel, but the mating pinion looks completely clean.
In a standard reduction drive, the gear wheel is the larger, slower-turning component on the output shaft.
Also heard as
- gear
- cogwheel
Do not mix it up with
- Pinion: The pinion is the smaller of the two mating gears, while the gear wheel is the larger one.
Related terms
Pinion
The smaller of two meshing gears, usually the driver in a speed reducer.
Bull gear
Shop name for the biggest gear in a drive train, usually the slow, heavy output gear.
Gear ratio
The number of teeth on the driven gear divided by those on the driver, setting speed reduction and torque gain.
Mesh
The engagement of two gears' teeth, or the zone where they meet; also the verb for gears engaging.