Hub Motor (In-Wheel Motor)

A drive motor built directly into a wheel's hub, turning the wheel itself.

A hub motor packs the entire motor inside the wheel, usually as an outrunner design: the outer shell turns together with the tire, eliminating the need for a drive shaft, gearbox, or belt. It's compact, has low transmission losses, and lets each wheel be controlled independently, so it's common in e-bikes and self-balancing scooters, and also used in mobile-robot chassis and the foot-wheels of wheeled-legged robots. Its downsides are that it makes the wheel heavier (adding unsprung mass, which hurts suspension performance), demands more from motor cooling and waterproofing, and often still needs a reducer for low-speed, high-torque situations. For robots, it simplifies chassis design, since differential steering just means controlling the left and right wheel speeds independently.

ExampleMany DIY mobile robots repurpose hub motors salvaged from self-balancing scooters as chassis drive wheels.

Also called

In-Wheel Motor

Related

Mobile Base (Chassis) · Differential Drive Base · Wheel-legged Robot · Outrunner Motor · Direct Drive

Sources

Wheel hub motor - Wikipedia