A8V Series A8V40SR1.1R131G1 Hydraulic Piston Pump For Excavators

1、 Disassembly and tightening of pump body bolts The hydraulic piston pump on construction machinery has been used in vibration for a long time. If the bolts on the repaired pump do not meet the torque standard, it will cause a series of hidden dangers and violations. The bolt tightening exceeds the standard torque and damages the bolt. Experienced maintenance personnel can achieve tightening standards without torque handling. But for another group of inexperienced people, there is a convenient and practical method to introduce to everyone. Before repairing the pump, the surface of the bolts should be cleaned of dust and dirt. Before disassembling the bolts, a marked connecting line should be made between the bolts and the pump casing. When disassembling the bolts, it is not allowed to remove one bolt at a time and then another. This type of bolt disassembly can damage both the pump casing and the bolts. The correct method is to unscrew all the bolts on the pump casing diagonally by 30 °, and then proceed with another round of disassembly by 30 °. Only after all the bolts on the pump casing have been disassembled and loosened can the bolts be removed from the pump casing.

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Detection of Arc Friction Pair in Plunger Pump
1. The variable rack of the pump is a friction pair with a precision fit of convex and concave. In order to reduce the friction torque and wear between the convex and concave pairs when the pump is in operation, a high-pressure oil is introduced from the P port of the pump to establish a strong oil film between the convex and concave curved surfaces (as shown in Figure 1). If the convex and concave curved surfaces cannot achieve the matching accuracy, there will be leakage between the friction pairs. When the pump is in high pressure, the pump flow will be severely reduced, In severe cases, there may be pressure to establish.
The method for checking the curved surface of the variable holder is to clean the variable holder, stack the convex and concave friction pairs, press the winding flange on top with your hand, and use a pen tube to forcefully blow smoke into hole A. If these friction pairs do not meet the required fitting accuracy, smoke will leak out between the curved surfaces, indicating that their fitting accuracy is low and cannot be assembled into the pump. The variable mechanism in Komatsu, Hitachi, and Carter pumps can all be checked using this method.
2. The arc-shaped distribution plate and rear cover of the pump
The curved surface of the valve plate and the variable slide on the rear cover of this pump are a pair of ultra precision friction pairs, even if there is a slight leakage,
3. Inspection of the mating surface between the arc-shaped port plate and the cylinder block
Install the valve plate onto the curved slide, and one person presses the oil passage on the surface of the valve plate with their palm to prevent air leakage from the oil passage hole. Another person uses their mouth to forcefully blow smoke into the high-pressure port, and if smoke leaks from a certain point on the valve plate, it is the fault point. This test method is used at three locations on an arc, namely the left, middle, and right of the variable slide. If there is smoke leakage in these three places, it indicates that the distribution plate and variable arc channel are in good coordination.

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