【 Weak current College 】 hydraulic pump symptom and cause analysis---Power By 【 China power house network 】

Symptom and cause analysis:

In maintenance from the following three points to find the cause of the failure, and to make improvements to the system:

(1) inspection boom cylinder of internal leakage. The easiest way is to arm rises to see whether there are obvious free fall. If the whereabouts of the obvious is removable tank inspection, sealing ring if it has been worn and should be replaced.

(2) check the control valve. First clean the safety valve, check valve wear, such as wear should be replaced. Safety valve installation if there is still no change, and then check the control valve wear, its clearance use limits generally wear 0.06mm, should be replaced.

(3) measuring the pressure of the hydraulic pump. If the pressure is low, you make an adjustment, and adjust the pressure is still not up, the hydraulic pump badly worn.

1. in General, resulting in a boom with load cannot be raised by the main causes are:

A. hydraulic pump badly worn. In low-speed operation pump leak seriously; high-speed operation, pump pressure slightly higher, but since the pump wear and volumetric efficiency of internal leakage, sharply declined, it is difficult to attain the rated pressure. Hydraulic pump to work long hours and increased wear, oil temperature rises, the resulting hydraulic component wear and seals aging, damage, loss of ability to seal, the hydraulic oil deterioration, the final result of the failure.

B. selection of hydraulic components. Boom cylinder specifications to 70/40 non-standard series, seals are non-standard, manufacturing costs and seal replacement. Boom cylinder bore is bound to make small, set high pressure systems.

C. design of hydraulic system. We know from Figure 1, the control valve and hydraulic steering pump for single-line, the safety valve set pressure 16MPa separation, and hydraulic pump rated working pressure 16MPa also. Hydraulic pump regularly in full load or long overload (high pressure) cases, and system has a hydraulic shocks, for a long time to change the oil, hydraulic oil contaminated, exacerbate the hydraulic pumps and wear, which breaking hydraulic pump casing (following the discovery of such failures).

2. improved and effects.

(L) improved the design of the hydraulic system. After repeated argument, finally adopts advanced priority valve and load sensing full hydraulic steering gear, the new system will give priority in accordance with the requirements, turning to assign traffic, regardless of the load size, wheel speed and low oil supply can be guaranteed adequate, all the remaining portion may supply working device circuit, thereby eliminating the oil supply due to steering circuit to cause power losses and improves system efficiency, reduce the pressure of the hydraulic pump.

(2) optimum design boom cylinders and hydraulic pump design, lower system working pressure. By optimizing the calculation, boom cylinder adopts standard series 80/4. Hydraulic pump displacement increase from 10ml/r r for 14ml/, system set pressure to 14MPa meets boom cylinder lifting power and speed requirements.

(3) in the course you should also note the loader's proper use and maintenance, periodic add or replace hydraulic oil, hydraulic oil cleanliness, strengthen the daily inspection and maintenance.