Due to the pressure of the hydraulic oil, the imbalance of forces causes torque to be generated in the rotor. The output torque of a vane-type hydraulic motor is related to the displacement of the hydraulic motor and the pressure difference between the inlet and outlet ports, while its speed is determined by the flow rate input to the hydraulic motor. Since hydraulic motors generally require reversible operation, the vanes of a vane-type hydraulic motor are arranged radially.
To ensure a constant flow of pressurized oil to the vane root, a check valve should be installed in the passage from the return and pressure oil chambers to the vane root. To ensure normal starting of the vane-type hydraulic motor after pressurized oil is introduced, the vane tip must be in tight contact with the inner surface of the stator to ensure a good seal; therefore, a preload spring should be installed at the vane root. Vane-type hydraulic motors are small in size, have low rotational inertia, and are highly sensitive, making them suitable for applications with high reversing frequencies; however, they have relatively high leakage and are unstable at low speeds. Therefore, vane-type hydraulic motors are generally used in applications requiring high speed, low torque, and sensitive operation.
