Excavator maintenance is an effective means to restore the technical performance of the excavator, troubleshoot and eliminate hidden troubles, and prolong the service life of the machine. At present, the domestic automobile maintenance industry has a considerable scale, but the excavator maintenance industry started relatively late, and there are still many technical problems in the maintenance. The existence of these problems has led to poor mechanical maintenance, poor equipment reliability, and even major excavator accidents.
In view of the common problems encountered in excavator maintenance work, according to the introduction of the excavator repair shop, there is a recent failure case about the boom that cannot be lifted with load. Generally, there are many reasons why the excavator boom cannot be lifted. It can be summarized as serious wear and tear of the hydraulic pump; unreasonable hydraulic components; reasonable hydraulic system design department.
Reasons why the boom cannot be lifted with load:
1. Excavator hydraulic pump is severely worn-leakage in the pump is serious when running at low speed; when running at high speed, the pump pressure is slightly increased, the volumetric efficiency is significantly reduced, and it is difficult to reach the rated pressure. Long-term operation of hydraulic pumps aggravates wear and oil temperature, which causes wear of hydraulic components and aging and damage of seals, loss of sealing ability, deterioration of hydraulic oil, and finally failure.
2. Unreasonable selection of hydraulic components-boom cylinder specifications are 70/40 non-standard series, and seals are also non-standard, high manufacturing costs and inconvenient replacement of seals. The small cylinder diameter of the boom cylinder will inevitably make the system set pressure high.
3. The design of the hydraulic system is unreasonable-the control valve and the full hydraulic steering gear are connected 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 also 16mpa. Hydraulic pumps often work under full load or long-term overload conditions, and have hydraulic shocks. If the oil is not changed for a long time, the hydraulic oil is contaminated, which aggravates the wear of the hydraulic pump and causes the pump casing to burst.
