1. Find a fault cause from the following three points during the repair machine and improve the system:
(1) Check the inner leakage of the boom cylinder. The easiest way is to raise the boiled boat and see if it has a significant freedom decline. If the drop is obvious, the cylinder is removed, and the sealing ring should be replaced if wear.
(2) Check the operating valve. First clean the safety valve, check if the spool is wear, such as the wear should be replaced.
If there is still no change in the safety valve installation, then the control valve valve core wear is inspected. The gap is usually 0.06mm, and the wear is severely replaced.
(3) Measure the pressure of the hydraulic pump. If the pressure is low, the adjustment is adjusted, and the pressure is still not being tested, then the hydraulic pump is severely worn.
In general, the main reasons why the boom belt cannot be improved is:
A. The hydraulic pump is severely worn. When the pump is severely leaked during low speed; when the speed is run, the pump pressure is slightly improved, but due to the wear and internal leakage of the pump, it is difficult to reach the rated pressure.
Hydraulic pumps have exacerbated wear, increased oil temperature, resulting in aging, damage, loss of sealing capacity, hydraulic oil deterioration, and final resulting in a hydraulic oil deterioration.
B. The selection of hydraulic components is unreasonable. The motor arm cylinder is 70/40 non-standard series, and the seal is also non-standard, manufacturing high and inconvenient replacement of the seal. The boom cylinder block is small, which is bound to make the system modulate the pressure.
C. Hydraulic system design is unreasonable. The manipulation valve and the full hydraulic steering are single pump tandem, the safety valve modulates the pressure of 16 MPa, and the rated operating pressure of the hydraulic pump is 16 MPa. Hydraulic pumps are often operated in the case of full load or long-term overload (high pressure), and the system has liquid impact, long-term non-changing oil, hydraulic oil is contaminated, exacerbated hydraulic pump wear, so that the hydraulic pump housing fry (after discovery Such faults).
2, improvement and effect
(1) Improve hydraulic system design. After multiple arguments, the final use of advanced priority valves and load sensing full hydraulic steering gear is used. The new system can allocate traffic in accordance with the steering requirements, regardless of the load size, the directional disk rotation speed can ensure that the oil supply can be supplied, and the remainder can be used to use the workfinder circuit, thereby eliminating the excessive power supply of the steering circuit. Loss, improved system efficiency, reduced the working pressure of the hydraulic pump.
(2) Optimize the design of the dynamic arm cylinder and hydraulic pump, reducing system working pressure. By optimizing the calculation, the boom cylinder uses a standard series 80/4. The hydraulic pump assembly is increased from 10 ml / R to 14 ml / r, and the system is determined to 14MPa to meet the booming and speed requirements of the boom tank.
(3) In the process of use, you should pay attention to the correct use and maintenance of the loader, regularly add or replace the hydraulic oil to maintain the cleanliness of hydraulic oil, and strengthen daily inspections and maintenance.
