Created on:2021-11-30 15:55

Structural characteristics and application of double acting vane pump

Structural characteristics and application of double acting vane pump

1. Several important structures and parameters of double acting vane pump

(1) Oil distribution pan.

1) Oil sealing area. Figure B shows the Yb type oil distribution plate structure. In order to achieve the purpose of sealing and flow distribution, there are two oil suction windows 2 and 4 and two oil pressure windows 1 and 3 on the plate. There is an oil sealing area between the two groups of windows. Generally, the center angle B corresponding to the oil sealing area should be slightly greater than or equal to the clamping angle between the two blades, otherwise the oil suction chamber and oil pressure chamber will be connected, resulting in internal leakage of the two chambers.

2) Unloading slot. During the transition of the sealing oil between the two blades from the oil absorption area to the oil sealing area (at the long radius arc), the oil pressure is basically the same as the oil absorption pressure, but when the rotor continues to rotate for a small angle, the sealing chamber will suddenly connect with the oil pressure chamber, resulting in a sudden increase in the pressure of the oil chamber, resulting in a great pressure impact, and the volume of the oil will suddenly shrink, It leads to the backflow of oil in the pressure oil chamber, causing the flow pulsation, pressure pulsation and noise of the hydraulic pump. In order to reduce the pressure impact at this time, a unloading groove (also known as eyebrow groove) with a triangular cross-section shape is respectively opened on the side of the two oil pressure windows 1 and 3 of the oil distribution plate entering the oil pressure area by the blade oil sealing area, as shown in Figure B, so that the closed oil between the two blades is connected with the pressure oil through the triangular groove before entering the oil pressure area, and its pressure increases gradually, Thus, the pulsation of flow and pressure is alleviated and the noise is reduced.

3) Annular groove. As shown in Figure B, in order to ensure that the blade can be thrown out along the radial groove in time and close to the inner cavity surface of the stator during high-speed rotation, an annular groove is set in the middle of the port plate, which is connected with the oil pressure cavity and the bottom of the rotor blade groove, which can make the bottom of the blade act with pressure oil and help the blade move outward quickly under the action of pressure oil.

(2) Stator curve. The stator cavity curve is composed of 4 segments of arc and 4 segments of transition curve. During high-speed movement, ensure that the blade is always close to the transition curve of the inner surface of the stator to form an isolated sealing space. In order to make the acceleration of the blade moving radially in the rotor slot change evenly and the impact of the blade on the stator surface as small as possible, the current stator curves mostly adopt the moving law curve and high-order curve of "equal acceleration and equal deceleration".

(3) The inclination of the blades. When the blade moves to the oil pressure area, it will be forced to squeeze the blade back into the groove by the great force exerted on it by the inner surface of the stator. At this time, due to the steep curve of the stator surface, the pressure angle applied to the blade will be large, which will affect the smooth return of the blade, which will increase the pressure between the blade, stator and rotor groove and aggravate the mutual wear, In severe cases, the blade may even be stuck. In order to reduce the pressure angle of the blade at this time, tilt the blade forward one along the rotation direction of the rotor θ In this way, the pressure angle can be effectively reduced, the blade can move flexibly in the slot smoothly, and the pressure and wear on the stator surface are reduced. According to the geometric parameters of the inner surface of the stator of the double acting vane pump, the maximum value of the pressure angle is β max≈24°。 Usually take θ= (1/2) β Max, so the daily inclination of vane pump blades is generally 10 ° ~ 14 °, and the forward inclination of Yb vane pump blades is 13 °.

2. Characteristics and application of double acting vane pump

The structure of double acting vane pump is more complex than that of gear pump, but its working pressure is higher than that of gear pump, and the flow pulsation is small (the number of blades of double acting vane pump is generally 12 or 16), with stable operation, low noise and long service life. Therefore, it is widely used in medium and low pressure hydraulic systems such as special machine tools and automatic lines in mechanical manufacturing. The general working pressure is about 16MPa, but its structure is complex, its oil absorption characteristics are not very good, and it is also sensitive to oil pollution.

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