Spare Parts Swing Motor AP5S53 AP5S63 AP5D67 EX60-2 EX60-3 EX105-2 EX100-2 EX100-3 EX100-5 EX120-2 EX120-3 EX120-5 AP5S67 ZAX120

In the hydraulic system of the operating equipment, the boom and the reversal operation are not normal, resulting in many reasons. It can include the previous fault appearance, but also related to the main safety valve, hydraulic pump, oil filter, hydraulic oil, distribution valve inlet and return oil circuit faults. Because there are many points of contact, we can start from easy to difficult, starting from the critical point. Let's check the most intuitive point, check the oil tank for sufficient oil, check the cleanliness, color, viscosity, consistency and smell of the hydraulic oil. When the hydraulic oil flows from the high pressure side to the low pressure side without mechanical work, heat will occur in the hydraulic system. Too high hydraulic oil temperature will make the sealing parts disintegrate and the oil will be oxidized to failure, which will cause corrosion and deposit, so as to block the damping hole and the abrasion of accelerating valve. Too high temperature will cause the valve and pump to be stuck. In case of doubt, sweep first and then check several critical parts. In terms of probability, the large-arm slide valve and the reversal slide valve are damaged together, and the large-arm oil cylinder and the reversal oil cylinder have less ability of internal leakage. Therefore, we mainly test the system pressure. Detection of system pressure: install a pressure gauge with a range of 40MPa at the pressure measuring point. When the engine is rotating at extra speed, lift the boom to the highest position. At this moment, the gauge shows the highest pressure and the reading should be 27-28MPa.

If the system pressure is too low, the following aspects shall be analyzed and removed:

(1) Internal leakage of distribution valve: the primary causes of internal leakage of distribution valve are: the main valve core of the main safety valve is stuck, the cooperation clearance between the valve rod and the valve body is too large, the pressure regulating tension spring is damaged, the sealing parts in the valve are damaged or the valve body has sand holes, etc. Disassemble and check whether the cone valve of the main safety valve is stuck; Check the cooperation gap between the valve rod and the valve body. The normal cooperation gap shall be 0.005 ～ 0.025mm, and the repair limit shall be 0.04mm; Check the cooperation gap between the main valve core and the main valve bushing. The normal cooperation gap is 0.010~0.018mm, and the repair limit is 0.03mm. Check whether the pressure tension spring and the sealing elements in the valve are damaged.

(2) Internal leakage of operation pump: internal leakage of Japanese Komatsu accessory pump is shown as follows: loud noise during operation, higher engine speed, loud noise; A lot of copper chips can be seen in the oil filter. Dismantle and inspect the pump, and repair or replace the damaged pump.

(3) If all the above checks are normal, measure the pressure of the corresponding operating oil circuit, and measure it with a pressure gauge. When it is in two operating conditions of "reversing" and "boom lifting", the pressure of the operating oil circuit is only 10MPa, and the oil pressure of the pilot control system is only 0.5MPa (the normal value is 2.8MPa). While the operating oil pressure and the pilot control system oil pressure under other operating conditions are in line with the normal value, the schematic diagram of hydraulic operation is carefully analyzed, and it is found that the pilot oil circuit with priority of reverse operation and the pilot oil circuit with priority of large arm operation can be connected with the oil circuit of the left walking control valve and the straight walking valve. Therefore, it can be preliminarily judged that the high pressure oil in the "left walking control valve" has the effect on the "straight shuttle walking valve", When the valve core of the "linear walking shuttle valve" is not in the neutral position, the pilot operation control oil path of the "reversing" and the "large arm lifting and lowering" passes through the "shuttle valve" and the "linear walking valve" and is released by the bypass. When the "left walking" operating handle is slightly operated, the "reversing" and "large arm lifting" actions are accelerated. Therefore, the "tension spring and oil seal" at the end of the "left walking control valve" are damaged. The "left walking control valve" is removed It was found that the oil seal and tension spring had been significantly damaged. After replacing the new tension spring and oil seal, the problem was removed