Its principle of action is similar to that of a single-acting vane pump. The only difference is that the stator surface is composed of two long-radius arcs, two short-radius arcs and four transition curves. The stator and rotor are concentric. . When the rotor rotates clockwise as shown in the figure, the volume of the sealed working chamber gradually increases at the upper left corner and lower right corner, which is the oil suction area, and gradually decreases at the lower left corner and upper right corner, which is the oil pressure area; the oil suction area There is a section of oil sealing area between them and the pressure oil area to separate them. Each time the rotor of this pump rotates, each sealed working chamber completes the oil suction and oil pressure actions twice, so it is called a double-acting vane pump. The two suction areas and two pressure areas of the pump are radially symmetrical, and the hydraulic pressure acting on the rotor is radially balanced, so it is also called a balanced vane pump.
The instantaneous flow rate of the double-acting vane pump is pulsating, and the pulsation rate is small when the number of vanes is a multiple of 4. For this reason, the number of blades of a double-acting vane pump is generally 12 or 16.
