The hydraulic pump is often worn, and the cause of the fault is:
Check the internal leakage of boom cylinder. The simplest way is to raise the boom and see if it has obvious free fall. If the drop is obvious, disassemble the oil cylinder for inspection, and replace the sealing ring if it is worn.
Check the control valve. First, clean the safety valve and check whether the valve core is worn. If worn, replace it.
If there is still no change after the installation of the safety valve, then check the wear of the control valve spool. The gap service limit is generally 0.06mm, and it should be replaced if it is seriously worn.
Measure the pressure of the hydraulic pump. If the pressure is low, adjust it. If the pressure still cannot be adjusted, it indicates that the hydraulic pump is seriously worn.
Generally speaking, the main reasons why the boom cannot be lifted with load are: a The hydraulic pump is severely worn. Serious leakage in the pump during low-speed operation; When running at high speed, the pump pressure increases slightly, but due to the wear and internal leakage of the pump, the volumetric efficiency decreases significantly, and it is difficult to reach the rated pressure. The long-term operation of the hydraulic pump intensifies the wear and tear, and the oil temperature rises, resulting in the wear of hydraulic components and the aging and damage of seals, loss of sealing capacity, deterioration of hydraulic oil, and finally failure.
The selection of hydraulic components is unreasonable. The seals are also non-standard parts, with high manufacturing costs and inconvenient replacement of seals. The small cylinder diameter of boom cylinder will inevitably make the set pressure of the system high. The design of hydraulic system is unreasonable. It can be seen from Figure 1 that the control valve and the full hydraulic steering gear are single pump in series. The hydraulic pump often works under full load or overload (high pressure) for a long time, and the system has hydraulic impact. The oil is not changed for a long time. The hydraulic oil is polluted, which intensifies the wear of the hydraulic pump, resulting in the cracking of the pump shell.
After many demonstrations, the advanced priority valve and load sensing full hydraulic steering gear are finally adopted. According to the Steering requirements, the new system can give priority to the distribution of flow to it. Regardless of the size of the load and the speed of the steering wheel, it can ensure sufficient oil supply, and the rest can be supplied to the working device circuit, so as to eliminate the loss of success rate caused by excessive oil supply in the steering circuit, improve the system efficiency, and reduce 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 requirements of lifting force and speed of boom cylinder are met. In the process of use, we should also pay attention to the correct use and maintenance of the loader, add or replace hydraulic oil regularly, maintain the cleanliness of hydraulic oil, and strengthen daily inspection and maintenance.
