In order to increase the maximum working pressure of the Fixed Vane Pumps, the main structural measures are: to make the vane reliably contact the inner surface of the stator, but also to prevent the contact stress between the two from being too large and causing serious wear. . In the early days, the maximum working pressure of vane pumps was not more than 6.3MPa, and some of the maximum working pressures of vane pumps in the world have reached 20-30MPa. To realize the high pressure of the vane pump, the following two problems must be solved. That is, the leakage problem of the rotor end surface and the top of the blade and the wear problem of the inner surface of the blade and the stator.

The so-called double blade means that two relatively freely sliding blades are installed in the same blade slot. The sealing edge of the top of each blade keeps good contact with the inner surface of the stator, and the chamfered part of the top of the two blades forms a small oil cavity. , The oil cavity a at the bottom of the blade always communicates with the pressure oil cavity of the pump outlet, or only communicates with the pressure oil cavity in the high pressure zone.

The vane oil cavity of the vane pump can be communicated through the gap b between the two vanes or the small hole b, so the top and bottom of the vane are basically equal in oil pressure, so that when the top and bottom of the vane are subjected to high-pressure oil pressure, the forces are basically balanced.

When designing a vane pump, the width of the oblique edge on the top of the vane is often selected to ensure that the vane has a certain tightening force and the inner surface of the stator is tight, so as to separate the high and low pressure chambers and prevent the high pressure of the vane pump. , High pressure produces excessive contact stress on the top of the blade, which intensifies wear and makes the blade slide flexibly in the blade groove. However, this double-blade structure requires Hydraulic Vane Pumps processing accuracy of the blades.