Gear trains

Gear trains consist of two or more interlocking gears that transmit torque and rotary motion.

Torque is turning force.

The gear’s teeth interlock to prevent slipping. The input gear is the driver gear and the output gear is the driven gear. The driven gear rotates in the opposite direction to the driver gear.

Changing direction

If the driven gear and the driver gear need to go in the same direction, an idler gear can be added. The idler gear’s size does not matter, and it does not alter the speed of gears.

Changing speed

Buy changing the size of gears, the output can become faster or slower.

A faster output speed is created by the driver gear being larger than the driven gear; a slower output speed is created by the driven gear being larger than the driver gear.

Gear ratios

Gear ratios are ways of comparing the sizes of gears.

The larger gear always equals 1. The smaller gear’s value is calculated by dividing the number of teeth on the larger gear by the number of teeth on the smaller gear.