Key Characteristics Of Hydraulic Orbital Motors

In this design the inner gear or rotor has one tooth less than the outer stator. This creates a gear ratio where the orbit speed is far lower than the rate at which the rotor rolls around the stator. This speed reduction has the effect of multiplying torque, so a hydraulic orbital motor produces high torque at low speed.

A second noteworthy feature is size. Placing the rotor inside the stator creates a compact design, resulting in higher power density, (a measure of torque produced for volume of motor), than other types of hydraulic motor.