Why Machining Accuracy Determines the Performance and Stability of Orbital Motors

In an orbital motor, hydraulic oil enters the high-pressure working chambers formed between the stator and the rotor. The pressure acting on these chambers drives the rotor and transfers torque to the output shaft, converting hydraulic energy into mechanical power.

The motor's output is created by the effective pressure acting on these sealed working chambers. In practice, the real geometry of each chamber and its sealing condition are defined by the machining accuracy of the stator–rotor set. This accuracy directly determines the motor's volumetric efficiency.

In service, a reduction in performance is most often related to internal leakage. In many cases, the root cause is insufficient matching accuracy between the stator and rotor, or wear of the working surfaces during operation. Once the running clearance is no longer properly controlled, high-pressure oil can pass into the low-pressure side, leading to pressure loss and a noticeable drop in output.

For this reason, the machining accuracy of the stator–rotor set is a fundamental factor behind both the performance and the operating stability of an orbital motor. A precisely manufactured and well-matched stator–rotor pair is essential for maintaining effective sealing, stable output and reliable operation over the motor's service life.