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Is the cause of hydraulic system pressure insufficient or no?How to diagnose and eliminate?

2016-10-10 14:04:16

Hydraulic system pressure is insufficient or completely without pressure, diagnosis, and eliminate the cause of, can according to the following aspects:
(1) the hydraulic oil hydraulic pump can output.Without hydraulic oil output, could be the turning of the pump is wrong, badly worn or damaged parts: suction pipe resistance is too much (blocking oil filter, oil viscosity, etc.) or air leakage.If it is a new hydraulic pump, the likelihood is the pump body of casting defects (shrinkage, sand holes, etc.), the oil pressure and oil absorption cavity are interlinked, lose pressure capacity, input power is insufficient, make the oil pressure can not meet the working pressure of the pump, pump shaft twist off, and no oil.
If there is the oil hydraulic pump output, should check the return pipe, see which parts of oil spill.Such as relief valve return pipe of oil spill, may be setting pressure is low.At this point, tighten the overflow valve pressure regulating spring, if there were no changes in pressure, could be the overflow valve is the main valve core or pilot section of the cone valve by dirt or rust stuck in open position;Or because of spring break off;Or because of the damping hole were choked up with dirt, oil pump output immediately after the overflow valve flow back into the tank.Excluded methods: relief valve should be apart, to be clean.Check or replace spring, restore its work performance.
(2) the work the overflow valve is normal.If not normal, it is probably one of the valve pressure oil stuck with dirt or other reasons, in the oil return position, the pressure oil with short circuit, the overflow loop may also be a loose coupling, or in some of oil pressure valve leakage is serious, or hydraulic cylinder, hydraulic motor seal damage, serious leakage.Elimination method: open the valve for cleaning, check the size of the seal clearance and all kinds of sealing device, sealing device damage should be replaced.
(3) if the hydraulic pump output flow decreases significantly with the pressure, and pressure and can not meet the specified value, is due to hydraulic pump wear after clearance increases.Method: determination of hydraulic pump volume efficiency, it can determine whether the pump can continue to use, to wear parts, should be for repair or replacement.
(4) if the entire hydraulic system is to establish normal pressure, and some piping or no pressure in the hydraulic cylinder or hydraulic motor, may be due to line, hole or blockage in areas such as the throttle valve, reversing valve.At this point, you should check pressure and the presence of oil by piecewise, find out why, to be ruled out.