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Ningbo Power Hydraulic Motor Co.,Ltd
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Hydraulic Pump Repair Failure Has Three Points

Hydraulic pump are usually made of aluminum alloy, high strength, corrosion resistance, light weight, suitable for a variety of environments.

Two-speed characteristics to reduce the number of times in the low-pressure chamber quickly in the load power state, immediately converted to high pressure, shorten the cycle of each operation.

Equipped with pressure regulating valve, adjustable control and set working pressure.

1, the phenomenon of failure and analysis

In the maintenance from the following three points to find the cause of the malfunction, and to improve the system:

(1) Check the internal pressure of the boom cylinder. The easiest way is to raise the boom to see if there is a clear free fall. If the drop is clear, then remove the cylinder inspection, the seal should be replaced if the wear and tear.

(2) Check the control valve. First clean the safety valve, check the spool wear, such as wear and tear should be replaced. If there is no change after the installation of the safety valve, and then check the valve spool wear situation, the gap limit is generally used 0.06mm, wear should be replaced seriously.

(3) measure the pressure of the hydraulic pump. If the pressure is low, then adjust, the pressure is still not up, then the hydraulic pump serious wear and tear.

In general, the main cause of the boom can not be raised:

A. The hydraulic pump is severely worn. In the low-speed operation of the pump leakage is serious; high-speed operation, the pump pressure slightly improved, but because of the pump wear and leakage, volumetric efficiency decreased significantly, it is difficult to achieve the rated pressure. Hydraulic pump for a long time work has exacerbated the wear and tear, oil temperature rise, resulting in hydraulic components wear and sealing of the aging, damage, loss of sealing capacity, hydraulic oil deterioration, and finally lead to failure.

B. Hydraulic components selection is unreasonable. Boom cylinder specifications for the 70/40 non-standard series, the seal is also non-standard parts, high manufacturing costs and the replacement of the seal inconvenience. Boiler cylinder bore is small, is bound to make the system set the pressure high.

C. Hydraulic system design is unreasonable. The control valve and the whole hydraulic steering gear for the single pump in series, the safety valve set pressure 16MPa, and the rated working pressure of the hydraulic pump is 16MPa. The hydraulic pump is often operated at full load or for extended periods of time (high pressure), and the system has a hydraulic shock, long-term oil change, hydraulic oil pollution, increased hydraulic pump wear, so that the hydraulic pump pump shell burst (later found Such failure).

2, improvement and effect

(L) Improved hydraulic system design. After several demonstrations, the final use of advanced priority valve and load sensing full hydraulic steering gear form, see Figure 2. The new system can be in accordance with the steering requirements, give priority to the distribution of its flow, regardless of the size of the load, the steering wheel speed can ensure adequate oil supply, the remaining part can be used to supply the working device circuit, eliminating the power supply due to excessive steering circuit Loss, improve the system efficiency, reduce the working pressure of the hydraulic pump.

(2) optimize the design of boom and hydraulic pump modeling, reduce system operating pressure. By optimizing the calculation, the boom cylinder uses the standard series 80/4. Hydraulic pump displacement from 10ml / r increased to 14ml / r, the system set the pressure of 14MPa, to meet the boom cylinder lift and speed requirements.

(3) in the course of the use of the loader should also pay attention to the correct use and maintenance, regular addition or replacement of hydraulic oil to maintain the cleanliness of hydraulic oil to strengthen the daily inspection and maintenance.