When the rotor of vane pump rotates, under the action of centrifugal force and pressure oil, the tip of vane clings to the inner surface of stator. In this way, the working volume formed by the two blades, the rotor and the inner surface of the stator first absorbs oil from small to large and then discharges oil from large to small. When the blades rotate for one circle, the oil absorption and discharge are completed once.
1、 Working principle of single acting vane pump
The pump is composed of rotor 1, stator 2, blade 3, oil distribution plate and end cover. The inner surface of the stator is a cylindrical hole. There is eccentricity between rotor and stator. The blade can slide flexibly in the groove of the rotor. Under the centrifugal force when the rotor rotates and the pressure oil flowing into the root of the blade, the top of the blade is close to the inner surface of the stator, so the two adjacent blades, oil distribution plate, stator and rotor form a sealed working cavity. When the rotor rotates in a counter clockwise direction, the blade on the right side of the figure stretches out, the volume of the sealing working chamber increases gradually, creating a vacuum, so the oil is sucked in through the oil suction port 6 and the window on the oil distribution plate 5. On the left. When the blades are retracted in, the volume of the sealing chamber is gradually reduced, and the oil in the sealing chamber is pressed out through another window of the oil distribution plate and the oil pressure port 1, and then it is output to the system. This kind of pump is called single acting pump because it sucks oil and presses oil once in the process of rotor rotation. The rotor is subjected to the unbalanced force of radial hydraulic pressure, so it is also called the unbalanced pump, and its bearing load is large. The displacement of the pump can be changed by changing the eccentricity between the stator and the rotor, so this kind of pump is variable displacement pump.
2、 Working principle of double acting vane pump
Its working principle is similar to that of single acting vane pump, except that the stator surface is composed of eight parts, i.e. two long radius arcs, two short radius arcs and four transition curves, and the stator and rotor are concentric. When the rotor rotates clockwise as shown in the figure, the volume of the sealing working chamber increases gradually at the upper left corner and the lower right corner, which is the oil absorption area, and decreases gradually at the lower left corner and the upper right corner, which is the oil pressure area; there is a section of oil sealing area between the oil absorption area and the oil pressure area to separate them. This kind of pump is called double acting vane pump because every rotor rotates, each sealed working chamber completes oil suction and pressure action twice respectively. The two oil suction areas and two oil pressure areas of the pump are radially symmetric, and the hydraulic pressure acting on the rotor is in radial balance, so it is also called balanced vane pump.
The instantaneous flow of double acting vane pump is pulsating, and the pulsation rate is small when the number of vanes is multiple of 4. Therefore, the number of blades of double acting vane pump is generally 12 or 16.