In-Wheel Motor
In-wheel motor, also called a wheel-hub or hub motor, is a traction motor installed in or immediately beside a driven wheel rather than centrally in the vehicle body.
What the location changes
Placing torque production at the wheel can shorten or remove conventional half-shafts, differentials, and central reduction stages. Independent wheel motors can also give control systems direct torque authority at each wheel. The exact package may still include a reduction gear, brake, bearing, inverter connection, cooling circuit, and suspension interface.
The main boundary is location: an e-axle close to the wheels is not an in-wheel motor if the motor remains sprung on the body or subframe. Moving motor mass into the wheel can increase unsprung mass, affecting ride and wheel control. The assembly must also tolerate road shock, water, dirt, brake heat, limited space, and flexible high-voltage or coolant connections.
For the broader packaging context, see Integrated Electric Drive Units.