Vane pump not pumping oil? With the outlet pressure not going up?

Almost all causes of failure of "vane pump does not produce oil" may be that the pressure cannot rise or there is no pressure at all:

1. The oil distribution plate and the end surface (fixed surface) of the housing are in poor contact, and there is a large amount of dirt in between, causing part of the pressure oil in the oil pressure chamber to flow into the low-pressure area through the gap between the two. The output flow rate is reduced and should be Take it apart and clean it to make it tight;

2. If the end surface (sliding surface) of the oil distribution plate and the rotor is roughened, the wear is serious, the internal leakage is large, and the output flow is insufficient. You can first use coarser (not too coarse) sandpaper to polish the roughened high points, and then use fine emery cloth to polish it. Remove dents and use after polishing;

3. The inner hole (inner curved surface) of the stator is roughened and worn. The roughened and scratched grooves on the top circle of the blade and the curved surface bracket in the stator hole leak into the oil suction area, resulting in insufficient output flow. The inner curved surface of the stator can be sanded with metallographic sandpaper;

4. The vane and rear drill assembly (vane pump cartridge kit) is installed backwards;

5. The pump body has pores, trachoma, shrinkage porosity and other casting defects, which are broken down, causing the high and low pressure chambers to be partially connected and unable to absorb oil. At this time, the vane pump may need to be replaced;

6. The axial clearance is too large, that is, the thickness of the vane pump rotor is too different from the thickness of the stator and the depth of the vane pump body hole, or a paper pad was added during repair, causing the axial clearance to be too large and the internal leakage to be too large. increases, causing the output flow to decrease;

7. If the variable mechanism is adjusted incorrectly or there is something wrong, it can be dealt with as appropriate after the cause is found out;

8. The end face of the oil distribution plate is worn or has grooves, the internal leakage is large, and the output flow is insufficient. Generally, the end face of the oil distribution plate needs to be ground;

9. The oil filter is clogged, or the filtration accuracy is too high, and there is no oil or very little oil (depending on the degree of blockage). It can be disassembled and cleaned;

10. The viscosity of the hydraulic oil is too low, especially for small-capacity vane pumps. When the oil viscosity is too low or the oil temperature rises too high, the oil pumped out by the vane pump often cannot be loaded to the required pressure. This is because the oil viscosity is too low and the temperature rise causes internal leakage to increase;

11. For pressure-limiting variable vane pumps, when the pressure adjustment screw is not adjusted properly and exceeds the pressure-limiting pressure, the flow rate will be significantly reduced, and after entering the system, the pressure will hardly be higher;

12. After the internal parts of the vane pump are worn, although the pressure can be increased at low temperatures, after the equipment has been running for a period of time, the oil temperature rises, the internal leakage caused by wear is large, the pressure loss is also large, and the pressure cannot be increased at this time. (It cannot reach the highest level). If you want to adjust it hard at this time (tighten the relief valve), the needle will shake violently. At this time, it is certain that the vane pump is severely worn. If a new vane pump is replaced, the pressure will increase immediately;

13. The inner surface of the stator is scratched, resulting in poor contact between the top of the blade and the inner curved surface of the stator, large internal leakage, reduced flow, and difficulty in adjusting the pressure. At this time, the inner curved surface of the stator should be polished or the stator should be replaced;

14. For medium and high-pressure vane pumps equipped with pressure reducing valves, if the output pressure of the pressure reducing valve is adjusted too high, it will cause early wear of the top of the vane and the inner surface of the stator due to excessive contact stress. The leakage inside the vane pump is large, the output flow is reduced, and the pressure cannot be increased;