1、 The engine has enough power, but there is a phenomenon of silly car (stuffy car). The hydraulic pump itself also has a certain power. If the power of the hydraulic pump is greater than that of the engine, the phenomenon of stuffy car (stuffy car) will appear. This requires the hydraulic pump to be tested and debugged on the test bench, and the power of the hydraulic pump can be reduced to 95% of the engine power.
2、 When walking, the action of one handle is not ideal. The hydraulic pump is divided into front and rear pumps or left and right pumps. Walking deviation indicates that one pump is faulty. The simplest judgment method is to remove the two high-pressure oil pipes of the hydraulic pump and adjust them. If the original slow walking becomes faster and the fast walking becomes slower, it indicates that one pump is faulty. For such problems, just remove the hydraulic pump, The accessories in a pump can be processed or replaced, and then debugged on the test bench. At the same time, the problem of unsatisfactory handle is also solved.
3、 The engine has sufficient power and operates normally, while the machine is slow and unable to dig
1. The hydraulic pump of the excavator is a plunger variable displacement pump. When it works for a certain time, the components in the hydraulic pump (such as cylinder block, plunger, port plate, swing, etc.) will inevitably be excessively worn, resulting in a large number of internal leakage and uncoordinated parameter data, resulting in insufficient flow, high oil temperature, slow speed and unable to establish high pressure, so the action is slow and the excavation is weak. For such problems, the hydraulic pump must be removed and sent to the commissioning Department of the company to test the data of the hydraulic pump, confirm the problem of the excavator, replace the parts that can not be used, repair the parts that can be used, reassemble the hydraulic pump, and then go to the commissioning test-bed to match various series of soft parameters (such as pressure, flow, torque, power, etc.).
2. At the same time, the excavator also has an important hydraulic component multi-channel distribution valve, which includes main safety valve, secondary valve, jet valve, oil makeup valve, etc. If the pressure set by these safety valves cannot reach the standard pressure (the standard pressure of ex200-5 main safety valve is 320kg, while the current pressure is only 230kg), the excavation will be weak. In addition, if the clearance between the valve stem and the valve hole is too large due to wear and the valve stem return is not complete, it will lead to insufficient flow and slow speed. For such problems, remove the multi-channel distribution valve, directly raise the test bench for commissioning after sending it to the company, reset the pressure of all safety valves and eliminate the gap between the valve stem and the valve hole.
3. The hydraulic pumps on the excavator are equipped with pilot gear pump, which is mainly used to participate in the variable of the hydraulic pump and open the valve rod of the multi-channel distribution valve as the pilot oil to reverse it. If the gear pump is excessively worn and cannot establish a certain pressure or the pressure set by the safety valve on the gear pump is not enough, the hydraulic pump will always be in a low flow state, and the valve rod cannot be completely reversed, so the flow will be insufficient and the action will be slow, The pressure is not enough and the excavation is weak. For such problems, just replace the pilot gear pump or reset the pilot safety valve.
4、 When the engine is cold, everything is normal, when the engine is hot, the action is slow and the excavation is weak. This problem indicates that the hydraulic pump must be overhauled. The internal parts of the hydraulic pump are seriously worn, and the continued use may cause serious damage to the hydraulic pump parts. It is necessary to deal with or replace all worn parts inside, reassemble and then debug on the test bench, so as to restore the standard condition of the hydraulic pump.
