A Komatsu excavator can't move at high speed, but the engine does not emit black smoke. The excavator can't move when walking alone on the right, and other actions are normal.
Check the left and right traveling overflow of the excavator. The engine is reduced from 2000 rpm to 1400 rpm, smoke-free. The jib is operated alone, and the boom overflows. The 2000 rpm is direct, smoke-free, and the engine is choked. Adjust it to 1400 rpm to overflow. The engine emits black smoke until the engine shuts down. The oil pump and the nozzle are calibrated and the data are normal. This is the fault of the hydraulic pump. First, when the load is not large, the oil pressure output by the hydraulic pump does not reach the system pressure, and the hydraulic pump will not overflow If the load is too large, overflow will occur when the excavator cannot dig or move, or when the oil cylinder extends and retracts to the end point. The overload valve is only a little higher than the pressure set by the safety valve. That is to say, it has the function of one-level protection, which is equivalent to adding an additional insurance
The above description may be caused by the poor matching between the power of the hydraulic pump and the engine, and the adjustment mechanism of the hydraulic pump needs to be reset. If it is mechanically adjusted, the position of the accelerator lever and the position of the adjustment arm of the hydraulic pump should be adjusted well. The electric control hydraulic pump and the electric magnetic valve should also be adjusted in this respect It includes appropriate modification of the control program, because the performance of the machine will change after a long time, and it cannot be accurately controlled according to the original control program. In addition, it should be noted that the pressure of positive feedback or negative feedback must be correct. If it is incorrect, check and clean the pipelines and components of these oil circuits. It is better to reduce the power of the hydraulic pump appropriately. If the two pumps supply oil to the two traveling pumps respectively and the adjustment is not good, The output pressure and flow rate will be different
The boom, bucket and other actions of the excavator are normal, indicating that there is no problem with the main pump of the excavator Therefore, check that the pilot pressure of the right travel valve core of the control valve is 39bar, and check that the pressure from the overflow valve at the root of the right control valve to the rear pump regulator is 6bar within the normal range, indicating that the right travel valve core is completely switched The left travel and front movement of the excavator are combined, and the right travel can operate normally, indicating that the center joint and the right travel motor have no fault Plug the two oil inlet and return pipes of the right travel motor with plugs. The pressure of the rear pump during the right travel action is 36bar, which is abnormal. It is judged that the problem is on the main control valve. The check valve near the right travel valve core is found to be damaged. After the one-way valve of the excavator is damaged, it can not operate when the excavator is traveling alone, and other actions are normal. Replace the damaged one-way valve and eliminate the fault
