Created on:2021-10-21 14:02

Working principle and structure of double acting vane pump

Working principle and structure of double acting vane pump

Vane pump is most widely used in hydraulic system of machine tool. It has the advantages of compact structure, small volume, stable operation, low noise and long service life, but it also has the disadvantages of complex structure, poor oil absorption performance and sensitive to oil pollution. Generally, the working pressure of vane pump is 7MPa, and that of high-pressure vane pump can reach 14MPa. With the continuous improvement of structure and process materials, vane pump is also gradually developing towards medium and high pressure, and the rated pressure of existing products is as high as 28Mpa. According to whether the output flow is variable, the vane pump can be divided into quantitative vane pump and variable vane pump; According to the times of oil suction and pressure per revolution and the radial hydraulic pressure borne by shaft, bearing and other parts, the vane pump can be divided into variable vane pump and quantitative vane pump.

1. Basic working principle of double acting vane pump

The basic working principle of double acting vane pump is shown in Figure Z. it is composed of stator 1, rotor 2, blade 3 and oil distribution plate (not shown in the figure). The rotor axis of the double acting vane pump is coaxial with the geometric center of the stator; The inner surface curve of the stator is composed of two long radii R, two short radii R and four transition curves, forming a roughly oval inner cavity surface to form the change of sealing volume; The radial groove of the rotor is equipped with blades that can slide radially along the groove. With the help of the gravity of the blades, when the rotor rotates at high speed driven by the drive shaft, the blades move radially along the rotor groove and press against the inner surface of the stator under the action of centrifugal force and root pressure oil. In this way, two adjacent blades, the inner surface of the stator, the outer surface of the rotor and the oil distribution discs on both sides form an independent sealing space. When the rotor rotates in the direction shown in the figure, the sealing space on the small arc moves to the large arc through the transition curve. Due to the change of the stator curve, the volume of the sealing space continues to increase. At this time, the sealing volume is in the area of the oil suction chamber, and oil should be sucked in; Moving forward again, during the movement of the sealing space from the large arc through the transition curve to the small arc, the blade is gradually pressed into the groove by the inner wall of the stator, the volume of the sealing space becomes smaller, the oil is pressed out from the oil pressure port, and the oil pump process of oil suction and oil pressure is completed, and the same action occurs at the upper and lower sides of the rotor at the same time.

This vane pump has two symmetrical oil suction chambers and two oil pressure chambers. Therefore, in the process of each revolution of the rotor, each sealing space needs to complete oil suction and oil pressure twice, so it is called double acting vane pump.

The double acting vane pump adopts the structure of symmetrical oil suction chamber and oil pressure chamber on both sides, so the radial pressure acting on the rotor is balanced and will not cause radial eccentric load to the rotor rotating at high speed. Therefore, double acting vane pump is also called unloading vane pump.

In order to completely balance the radial force, the number of sealing spaces (i.e. the number of blades) should be kept even, and the stator curve should be symmetrical.

2. Basic structure of double acting vane pump

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As shown in figure a, it is the basic structure of a Yb type double acting vane pump. The whole pump adopts a separate structure. The pump body is composed of front pump body 7, rear pump body 1 and front end cover 8. Rotor 3, stator 4 and blade 5 become the main structure of the pump, and port plates 2 and 6 are configured on both sides. As can be seen from the figure, the oil suction port and the oil pressure port are respectively arranged on the rear pump body L and the front pump body 7, with a long distance, which can solve the problems of isolation and sealing. The whole rotor is supported in the pump body by rolling bearings 11 and 12 at both ends of the spline shaft. The sealing ring 10 can prevent the leakage of oil and the invasion of external dust and dirt.

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