Introducing Planetary Gear Reducers for In-Wheel Drive

The Ultimate in Space-Efficiency

One strength of planetary reduction mechanisms is its characteristic coaxial input and output. This structure provides the potential for seamless installment of the reduction gear on the same axis between the wheel and the motor, simplifying the overall layout.

Compared to multi-stage spur gear structures, it is possible to achieve a larger reduction ratio with fewer stages. Furthermore, a Planetary Gear Reducer can withstand higher torque levels due to its large number of meshing points.

In the example shown in the figure, the motor output shaft is used as the sun gear, and the output is connected to the wheel by fixing the internal gear and connecting the planetary carrier to the wheel.

It is also possible to fix the planetary carrier and connect the internal gear (ring gear) to the wheel to obtain the output.

As such, planetary reduction mechanisms are the ideal reducers for space-limited wheel-in-motors, being compatible with any type of motor. Since in-wheel motors can be controlled independently, they are often used in autonomous transport vehicles that require good maneuverability.