The hydraulic pump is the power source of the hydraulic system of the excavator. It is an energy conversion device that converts mechanical energy into hydraulic energy. In the hydraulic excavator, the hydraulic pump is also the component with the most failures. What are the common failures of the hydraulic pump? The excavator works frequently to repair the hydraulic pump. It is easy to wear. Today, the reason why the hydraulic pump is easy to wear is described.
cause of issue:
Check the inner leakage of the boom cylinder. The easiest way is to raise the boom to see if it has a clear free fall. If the drop is obvious, remove the cylinder and check. If the seal ring is worn, it should be replaced.
Check the control valve. First clean the safety valve, check whether the valve core is worn, and replace it if worn.
If there is no change after the safety valve is installed, then check the wear of the spool of the control valve. The clearance limit is generally 0.06mm, and it should be replaced if the wear is serious.
Measure the pressure of the hydraulic pump. If the pressure is low, adjust it, but the pressure can not be adjusted, it means that the hydraulic pump is seriously worn.
Generally speaking, the main reason that the boom load cannot be raised is: a. The hydraulic pump is seriously worn. During low-speed operation, the internal leakage of the pump is serious; during high-speed operation, the pump pressure is slightly increased, but due to the wear and internal leakage of the pump, the volumetric efficiency is significantly reduced, and it is difficult to reach the rated pressure. Long-term operation of the hydraulic pump intensifies the wear and the oil temperature rises, which causes the wear of the hydraulic components and the aging and damage of the seals, the loss of sealing ability, the deterioration of the hydraulic oil, and finally the failure.
Unreasonable selection of hydraulic components. The seal is also a non-standard part, and the manufacturing cost is high and the replacement of the seal is inconvenient. The small diameter of the boom cylinder will inevitably make the system set pressure high. The hydraulic system design is unreasonable. As can be seen from Figure 1, the control valve and the full hydraulic steering gear are single pumps in series. The hydraulic pump often works under full load or long-term overload (high pressure), and the system has hydraulic shock. Pollution, aggravating the wear of the hydraulic pump, so that the pump casing of the hydraulic pump burst.
After many demonstrations, finally adopt the advanced priority valve and load sensing full hydraulic steering gear. The new system can give priority to the flow distribution according to the steering requirements. No matter the load size or the steering wheel speed, it can ensure sufficient oil supply, and the remaining part can be fully supplied to the working device circuit, thereby eliminating the power caused by the excessive oil supply to the steering circuit Loss improves the efficiency of the system and reduces the working pressure of the hydraulic pump.
Optimize the design of boom cylinder and hydraulic pump to reduce the working pressure of the system. Through optimization calculation, the lifting force and speed requirements of the boom cylinder are met. During the use process, attention should also be paid to the correct use and maintenance of the loader, the hydraulic oil should be regularly added or replaced, the cleanliness of the hydraulic oil should be maintained, and the daily inspection and maintenance should be strengthened.
