The vane pump has the advantages of compact structure, small volume, stable rotation, uniform oil delivery and low noise. However, its structure is more complicated, the oil absorption characteristics are poor, the stator, rotor, and blades are more difficult to process, and the oil cleanliness requirements are stricter.
The vane pump is widely used. Its working pressure is (70-160)×105Pa, the flow rate is 4-200L/min, and the volumetric efficiency can reach more than 95%.
The vane pump is divided into single-acting (variable, internal and external feedback) and double-acting (quantitative) vane pumps according to the mode of action; divided into single-stage and bipolar vane pumps according to the number of stages; divided into single pumps and double pumps according to the connection form; according to work The pressure can be divided into medium pressure (6.3MPa) and medium and high pressure (6.3MPa-16MPa) vane pumps.
In the single-acting vane pump, when the rotor rotates once, each space completes an oil suction and pressure action, and the pressure and flow rate can be adjusted in a limited manner.
In the double-acting vane pump, when the rotor rotates once, each sealed working space completes two oil suction and oil pressure actions, and the pressure and flow cannot be adjusted.
There are mainly three gap leaks that affect the volumetric efficiency of the vane pump:
The gap between the rotor slot and the blade is equal to the slot width minus the blade thickness.
The gap between the height of the blade and the two oil distribution pans is equal to the height of the stator minus the height of the blade.
The gap between the rotor and the two oil distribution pans is equal to the height of the stator minus the height of the rotor.
The oil drain of the above three gaps accounts for 93% of the oil drain in the entire pump, which is the key to ensuring the volumetric efficiency of the vane pump. Experience tells us that the rotor slot width and blade thickness of quantitative pumps should be within 0.02-0.025mm, variable pumps should be within 0.025-0.04mm; the height of blades and stators should be within 0.005-0.01mm; the rotor and two oil distributions The disc gap should be within 0.045-0.055mm.
Repair of oil distribution pan and side plate: most of these two parts are end-face abrasion and strain. Lighter ones can be ground flat on a grinding plate and then assembled. Those with a strain depth greater than 0.3-0.8mm can be ground with a flat grinder to remove the scars, and then assembled after polishing and grinding. However, it is necessary to trim a proper amount of unloading triangle grooves to be deep and slender, which is beneficial to eliminate trapped oil.
Repair of the stator: When the inner arc curve of the stator is not severely worn and strained, it can be polished with 0# gauze or oil stone and used again. If the abrasion is severe, the stator can be turned over 180o to change the positions of the stator oil suction cavity and pressure oil cavity, and additional positioning pin holes are added at the symmetrical positions of the original pin holes, which can be reused. The inner surface of the stator can be polished and polished by machine tools such as lathes and drilling machines, but the roundness and cylindricity should be ensured.
Repair of the rotor: The rotor is mainly worn and roughed on both ends, and sometimes there are fractures or cracks at the keyway. If it is only slightly worn on both ends, it can be used after polishing and roughening. For severely worn and roughened, both ends should be polished on a cylindrical grinder. At this time, the corresponding size of the blade and stator is removed.
Blade repair: The damage of the blade mainly includes the wear and tear of the contact between the top of the blade and the inner surface of the stator and the relative sliding position of the end face and the oil distribution plate plane. Continue to use after the outer surface. But it must be ensured that the fit clearance is within 0.02-0.03mm, and the broken blades need to be updated and replaced with new blades.
Pump shaft repair: the general wear parts of the pump shaft are the key and spline connection and the pump shaft diameter bearing support. The connection between the pump shaft key and the spline can be repaired after repair welding. If the pump shaft support diameter is lightly worn, it can be polished and replaced with a new bearing (sleeve) before assembling. If the pump shaft support diameter is severely worn, it can be repaired with a cylindrical grinder and then polished and equipped with a support sleeve. The fit clearance is generally less than 0.02mm.
Link to this article：The Structure Principle And Maintenance Of Vane Pump
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