The use and maintenance of excavator hydraulic pump

Excavator hydraulic pump serious wear on the excavator has a fatal impact, so the excavator such problems must be resolved in a timely manner. When repairing the excavator hydraulic pump from the following three points to find the cause of failure.

   (1) check the internal leakage of the moving arm cylinder

    The easiest way is to lift the moving arm and see if there is an obvious free fall. If the drop is obvious then disassemble the cylinder to check, the seal should be replaced if it is worn.

    (2) Check the operating valve

    First clean the safety valve, check whether the valve spool is worn, such as wear should be replaced. If there is still no change after the installation of the safety valve, then check the operating valve spool wear, the gap use limit is generally 0.06MM, serious wear should be replaced.

    (3) Measure the pressure of the hydraulic pump

    If the pressure is low, then adjust, add pressure is still not adjusted up, it means that the hydraulic pump is seriously worn.

    A general cause of the moving arm with load can not be lifted for the following main reasons.

    1, excavator hydraulic pump serious wear and tear

    In low-speed operation, the pump leakage is serious; high-speed operation, the pump pressure slightly increased, but due to the wear of the pump and internal leakage, volumetric efficiency significantly decreased, it is difficult to reach the rated pressure. Hydraulic pump work for a long time and intensify the wear, oil temperature, resulting in wear and tear of hydraulic components and seals aging, damage, loss of sealing capacity, hydraulic oil degradation, and finally lead to failure.

    2, hydraulic components selection is not reasonable

    The moving arm cylinder specifications for 70 / 40 non-standard series, the seals are also non-standard parts, high manufacturing costs and seal replacement inconvenience. The movable arm cylinder bore is small, which will inevitably make the system adjust the pressure high.

    3, hydraulic system design is not reasonable

    Maneuvering valve and full hydraulic steering for a single pump in series, the safety valve setting pressure points 16MPA, while the hydraulic pump rated working pressure is also 16MPA. hydraulic pump often at full load or long time overload (high pressure), and the system has a hydraulic shock, long-term oil change, hydraulic oil contamination, intensify the wear and tear of the hydraulic pump, so that the hydraulic pump case blow (after the discovery of such failure).

    Second, the improvement and effect

    (1) improve the hydraulic system design

    After many times of demonstration, finally adopt the advanced priority valve and load sensing full hydraulic steering form. The new system can be in accordance with the steering requirements, priority to its distribution of flow, regardless of the size of the load, steering wheel speed can ensure sufficient oil supply, the remaining part can be supplied to the work device circuit to use, thus eliminating the power loss caused by excessive oil supply to the steering circuit, improve the efficiency of the system and reduce the working pressure of the hydraulic pump. Reduce the serious wear of excavator hydraulic pump.

    (2) Optimize the design of the movable arm cylinder and hydraulic pump shape

    Reduce the working pressure of the system. Through optimization calculation, the movable arm cylinder adopts standard series 80/4. The hydraulic pump displacement is increased from 10ML/R to 14ML/R, and the system pressure is set to 14MPA, which meets the lifting force and speed requirements of the movable arm cylinder.

    (3) Strengthen daily inspection and maintenance

    In the process of use should also pay attention to the correct use and maintenance of the loader, regularly add or replace hydraulic oil, keep the cleanliness of the hydraulic oil, and strengthen the daily inspection and maintenance. This will avoid serious wear and tear of the excavator hydraulic pump.