Planetary, Spur and Worm & wheel gearboxes

Normally, the sun-gear is driven and thus move the planet gears locked in the planet carrier and form the output shaft. The satellite gears have a fixed position in relation to the outside world. This looks like our planetary solar system and that is where the name comes from.

Spur gearboxes:
A spur gear head’s construction consists of larger gears that mesh with smaller gears. The gears are mounted on parallel shafts, but offset from one another. The meshing of the smaller gears with the larger gears reduces rpm transforming it into torque. The tooth pitch of the gears is critical in determining the final output speed and torque of the gear motor. Adding multiple gear stages within the gear head produces larger reduction ratios resulting in even lower output speed and higher output torque. Spur gearheads have a single contact point at any time. This means that any load is held entirely by a single point of contact between two gears.

Worm and wheel gearboxes:
A worm and wheel gearbox consists of a worm (screw-like shaft) that meshes with a worm wheel (similar to a spur gear). The shafts of the worm and wheel are arranged at a 90° angle, making this type of gearbox suitable when a change in the direction of drive is required. The gear ratio is determined by the number of teeth on the worm wheel in relation to the number of starts (threads) on the worm. This configuration allows for high reduction ratios in a compact size.

Another characteristic of worm gearboxes is their self-locking ability in certain setups, meaning the output shaft cannot drive the input shaft, which can be useful in applications requiring holding torque without additional brakes.