After the driving wheel drives the rotor to rotate, the blade opens under the action of centrifugal force, and forms a working cavity together with the stator, the rotor, and the oil distribution plate, when the rotor and the blade rotate from the small arc area on the inner surface of the stator to the large circular arc area, the volume between the two blades increases, the pressure decreases, and the oil is sucked through the oil suction port of the oil distribution plate;