Hydraulic cylinder manufacturer The failure phenomenon, cause analysis and improvement methods of.

1、 Fault Phenomenon and Cause Analysis of Hydraulic Oil Pump

1. Check the internal leakage of boom cylinder. The simple way is to raise the boom to see if it has obvious free fall. If the drop is obvious, disassemble the oil cylinder for inspection, and replace the seal ring if it is worn;

2. 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, check the wear condition of the control valve core. The use limit of the clearance is generally 0.06mm, and it should be replaced if the wear is serious;

3. Measure the pressure of hydraulic pump. If the pressure is too low, adjust it. If the pressure still cannot be adjusted, the hydraulic pump is severely worn.

In general, the main reasons that the boom of the hydraulic oil pump cannot be lifted under load are:

a. The hydraulic pump is severely worn. Serious leakage in the pump at low speed; At high speed, the pump pressure increases slightly, but due to wear and internal leakage of the pump, the volumetric efficiency decreases significantly, and it is difficult to reach the rated pressure. Long time operation of hydraulic pump aggravates wear and oil temperature rise, which causes wear of hydraulic components, aging and damage of sealing elements, loss of sealing ability, deterioration of hydraulic oil, and subsequent failure;

b. The selection of hydraulic components is unreasonable. The boom cylinder specification is 70/40 non-standard series, and the seal is also non-standard, so the manufacturing cost is high and it is inconvenient to replace the seal. The boom cylinder diameter is small, which is bound to make the system set pressure high;

c. The design of hydraulic oil pump system is unreasonable. It can be seen from Figure 1 that the control valve and the full hydraulic steering gear are in series with a single pump. The set pressure of the safety valve is 16MPa, and the rated working pressure of the hydraulic pump is 16MPa. The hydraulic pump often works under full load or overload (high pressure) for a long time, and the system has hydraulic impact, and the oil is not changed for a long time. The hydraulic oil is polluted, which aggravates the wear of the hydraulic pump, so that the pump shell of the hydraulic pump bursts (such failure was found later).

2、 Improvement and effect of hydraulic oil pump

1. Improvement Hydraulic system Design. After several demonstrations, the advanced priority valve and load sensing full hydraulic steering gear are adopted. The new system can give priority to the distribution of flow according to the steering requirements. Regardless of the load and the steering wheel speed, sufficient oil supply can be ensured. The rest can be supplied to the working device circuit, thus eliminating the loss of success rate caused by excessive oil supply in the steering circuit, The system efficiency is improved and the working pressure of the hydraulic pump is reduced;

2. Optimize the design of boom cylinder and hydraulic pump to reduce the working pressure of the system. Through optimization calculation, the boom cylinder adopts the standard series 80/4. The displacement of the hydraulic oil pump is increased from 10ml/r to 14ml/r, and the set pressure of the system is 14MPa, which meets the lifting force and speed requirements of the boom cylinder;

3. Pay attention to the correct use and maintenance of the loader hydraulic oil pump during use, Oil cylinder manufacturer Add or replace hydraulic oil regularly, keep the cleanliness of hydraulic oil, and strengthen daily inspection and maintenance.