1. The engine has enough power, but the phenomenon of slack (smooth) occurs. The hydraulic pump itself also has a certain power. If the power of the hydraulic pump is greater than the power of the engine, the phenomenon of slack (smooth) will occur. This requires the hydraulic pump to be tested and debugged on the experimental platform, and the power of the hydraulic pump can be reduced to 95% of the engine power.
2. Walking deviation, at the same time, the action of a handle is not ideal. The hydraulic pump is divided into front and rear pumps or left and right pumps. Walking deviation shows that one pump is faulty. The simplest method of judgment is to disassemble the two high-pressure oil pipes of the hydraulic pump. Check it out. If the original slow walking speed becomes faster and the fast walking speed becomes slower, it means that one pump is faulty. For such problems, you only need to remove the hydraulic pump and process or replace the accessories in one pump. , And then go to the experimental bench for debugging, but also solve the problem of a handle is not ideal.
Third, the engine power is sufficient, the operation is normal, and the machine is slow, and the digging is weak
1. The hydraulic pump of the excavator is a plunger variable pump. After working for a certain period of time, the original parts in the hydraulic pump (cylinder, plunger, valve plate, swing, etc.) will inevitably produce excessive wear, resulting in a large amount of internal leakage, various parameters The data is not coordinated, resulting in insufficient flow, too high oil temperature, slow speed, and high pressure cannot be established, so the action is slow to dig. For such problems, you must remove the hydraulic pump and send it to the commissioning department of the company to test the data of the hydraulic pump to confirm the problem of the excavator, replace the accessories that can no longer be used, repair the accessories that can be used, and reassemble the hydraulic pump After that, go to the commissioning test bench and match each series of soft parameters (such as: pressure, flow, torque, power, etc.).
2. The excavator also has an important hydraulic original multi-way distribution valve, which has a main safety valve, a secondary valve, a jet valve, a charge valve, etc. If the pressure set by these safety valves does not reach the standard pressure (the standard pressure of the EX200-5 main safety valve is 320kg, and the current pressure is only 230kg), it will cause weak excavation. In addition, if the gap between the valve stem and the valve hole is too large due to wear, and the valve stem is not completely returned, it will result in insufficient flow and slow speed. For such problems, you must remove the multi-way distribution valve, send it to the company and go directly to the debugging station for debugging, reset the pressure of all safety valves, and eliminate the gap between the valve stem and the valve hole.
3. The hydraulic pump on the excavator is equipped with a pilot gear pump. This pump is mainly involved in the variables of the hydraulic pump and the stem of the multi-way distribution valve opened as the pilot oil to change its direction. If the gear pump is worn too much, it cannot be established. A certain pressure or the pressure set by the safety valve on the gear pump is not enough, it will cause the hydraulic pump to always be in a low flow state, and the valve stem cannot be completely commutated, so that the flow will be insufficient, the action will be slow, the pressure will be insufficient, and the digging will be weak. In such cases, it is only necessary to replace the pilot gear pump or reset the pilot safety valve.
4. Everything is normal when the machine is cold, and the movement is slow when the machine is hot. The failure of digging is weak. This indicates that the hydraulic pump has to be overhauled. The internal parts of the hydraulic pump are seriously worn out. Continued use may cause serious damage to the hydraulic pump parts. . Need to deal with or replace all the worn parts inside, re-assemble and then go to the test bench for debugging, in order to restore the standard condition of the hydraulic pump.
