Gears

Work

The exertion or effort directed to produce or accomplish something.

Rack Gear

A gear mounted to a straight rod, such that it moves in a linear fashion when torque is applied to it by a spur gear (known as the pinion gear).

Crown Gear

A type of bevel gear in which the teeth project perpendicular to the gear face.

Bevel Gears

Conically shaped gears that transmit power between shafts that have intersecting axes of rotation.

Epicyclic (Planetary) Gears

Consists of one or more gears moving along an outer ring gear.

Helical Gears

Gears with teeth curved like a helix (spiral). Can transmit power between two axes of rotation, both parallel and perpendicular.

Gear Pitch

In order for two gears to mesh, they need to have the same size (and shape) teeth on the same spacing.

Idler Gear

The driven gear spins in the opposite direction as the driving gear. Used for reverse motion.

Torque

The magnitude of the force multiplied by the distance it is from the center of rotation (Force x Distance).

Gear Ratio

The relationship between the numbers of teeth on two meshing gears used to transmit motion. It reflects the change in mechanical advantage resulting from the gears.

Transmission

The transference of force between machines or mechanisms, often with changes of torque and speed.

Spur Gears

Transfer motion between two shafts running parallel to each other. They are characterized by their teeth, which are straight and parallel to the gears axis of rotation.

Worm

____________ gears come in pairs that mate together to transfer power between perpendicular shafts that have axes of rotation offset from one another. These gears resemble screws; as they spin they turn their mating wheel.

Mechanical Advantage

the ratio of output force to the input force applied to a mechanism.

Rotational Speed

Measured in units of angular-distance per time (i.e. degree per second) or rotational cycles per time (i.e. revolutions per minute.)