Its principle of action and single-acting vane pump Similar, the difference is that the stator surface is composed of two length radius arc, two short radius arc and four transition curve eight parts, and the stator and the rotor is concentric. In the case of rotating clockwise rotation of the rotor, the volume of the sealed working chamber increases gradually in the upper left and lower right corner, and is in the lower left and upper right corner, and gradually decreases in the upper and lower corners, for the pressure petroliferous region. There is an oil zone between the oil-absorbing oil region and the oil-pressure petroliferous region. This pump rotor every turn, each sealed working cavity to complete the suction oil and oil pressure two times each, so called double-acting vane pump.
The pump's two oil-absorbing region and two pressure oil region are radially symmetrical, acting on the rotor of the hydraulic force radial balance, so also known as the balance vane pump. The instantaneous flow of the double-acting vane pump is pulsating, and the pulsation rate is small when the number of blades is 4 multiples. For this reason, the number of blades for double-acting vane pumps generally takes 12 or 16.