Nidec announces in-wheel motor prototype for electric vehicles
Nidec introduced a prototype of a traction motor designed to be fitted inside the wheel hubs.
While regular electric vehicle (EV) traction motors generally occupy the engine compartment, in-wheel motors, as their name implies, are incorporated directly into the wheels of the automobile. Benefits of this set-up include higher efficiency as a result of driving the wheels directly and bypassing the need for conventional power transmission mechanisms. In turn, this allows for lighter and more compact designs. Additionally, independent control of the wheels opens up the possibility of making further improvements to electronic stability control (ESC) and traction control systems (TCS).
The most prominent features of Nidec's in-wheel motor are its high power and torque density and its lightweight properties. The prototype consists of a motor with integrated reduction gears and an oil cooling system. A single in-wheel motor can reportedly achieve a power output of more than 100 kW (135 PS)—equivalent to an 1800 cc class gasoline engine—while weighing 32 kg (70 lb) and being compact enough to fit inside a 20 in wheel. The motor is designed to be compatible with all of the common car layouts: RWD, FWD, and 4WD. The company aims to start mass-producing the motor around 2023.