Created on:2021-12-03 13:31

Solution to the imbalance of blade pressure of double acting vane pump

Solution to the imbalance of blade pressure of double acting vane pump

Generally, the bottom of the blade of the double acting vane pump adopts the ejector structure with pressure oil, but when the blade turns to the oil suction area, the top pressure is too small and tightly squeezed on the stator surface, resulting in excessive wear of the curve of the stator oil suction area. At the same time, this reason also seriously affects the further increase of the d-working pressure of the double acting vane pump, Therefore, in the structure of high-pressure vane pump, we can often see the following radial pressure equalization structures of vanes.

(1) Damping oil groove. In order to reduce the force of the oil at the bottom of the blade, we can try to reduce the pressure of the oil by connecting the oil in the pressure chamber of the pump to the bottom of the blade in the oil suction area through a damping groove or a small built-in pressure reducing valve, so as to reduce the oil pressure acting on the bottom of the blade, so that the force of the blade pressing against the inner surface of the stator will not be too large when the blade passes through the oil suction chamber.

(2) Thin blade structure. Reducing the area under the action of pressure oil at the bottom of the blade can reduce the stress at the bottom of the blade. Generally, the method of reducing the thickness of the blade is adopted. However, the minimum thickness of the blade is generally 1.8 ~ 2.5mm, which will affect the strength and rigidity of the blade.

(3) Step sheet structure. Fig. C (b) shows a stepped blade structure. The pressure oil chamber B is arranged in the middle of the blade. In this way, the radial force of the pressure oil on the blade is reduced by half due to the reduction of the radial bearing area. Although this method reduces the radial force of the blade to a certain extent, the oil also acts on the side of the blade, resulting in additional side pressure of the blade, It hinders the smooth sliding of the blade. In addition, the manufacturability of this structure is also poor.

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(4) Compound blade structure. Fig. C (a) shows a composite blade (also known as sub parent blade) structure. The blade is made into a sub parent composite structure. An independent oil chamber C is formed with the sub blade in the middle of the bottom of the parent blade, and the C chamber is always connected with pressure oil through the oil distribution pan and oil groove K, while the L chamber at the bottom of the parent blade is always the same as the top oil pressure with the help of the oil}l shown by the dotted line. In this way, when the blade is in the oil suction chamber, only the pressure oil in chamber C acts on the bearing surface of the mother blade with a small area, which reduces the force at the bottom of the blade, and the oil force can be controlled by adjusting the area of this part.

(5) Double blade structure. Fig. D (a) shows a double blade structure. Two freely sliding blades 1 and 2 are placed in each groove at the same time, and a hole C is arranged at the joint surface of the two blades to keep connected with the oil cavity a formed at the top of the blade. In this way, the liquid pressure at the top and bottom of the blade can be balanced through this hole C.

Figure D (b) shows the blade ejection structure with spring. In this structure, the blade 1 is thick, and there are small holes at the top and bottom. The oil at the bottom of the blade is introduced from the top of the blade through the small holes of the blade. If the pressure drop of the small holes is not considered, the acting force of the oil in the upper and lower oil cavities of the blade is always balanced, The blade is basically close to the inner surface of the stator by the force of the bottom spring to ensure sealing.

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