Common Fault Analysis of Single Piston Pump Hydraulic System
November 04, 2024
Common failures in the hydraulic system can be grouped into four types: empty load can not be improved; heavy load can not be improved; slow speed and jitter accompanied by lifting phenomenon; when the joystick is placed in a neutral position, the implement drops rapidly.
In the hydraulic system failure analysis, can be divided into two sections: the fuel tank, the pump for the first section, responsible for the oil supply and the low-pressure oil into high-pressure oil, the hydraulic system is the power part of the cylinder as the second Section.
An empty load can not be increased Loose pump and cylinder connection pipe joints, observe the pump work. If the pump oil, indicating the normal operation of the first section; the other hand, that the first section is faulty.
1. Belongs to the first section of fault (1) separation block stuck. The clutch handle placed in the joint position, see the top of the separation shaft drop situation, such as the whereabouts of incomplete, indicating that the separation block stuck. In this case, loosen slightly the three bolts of the oil pump and move the oil pump slightly to eliminate the jamming of the separation block, and then tighten the three bolts evenly.
(2) too little hydraulic oil, the tank lack of oil. Can be observed through the transparent plastic pipe of the low-pressure oil line, or release the low-pressure oil pipe joint. If the oil level is too low, add hydraulic oil.
(3) A serious oil leak, such as one-way valve sealing surface uneven or clutter; safety valve steel ball seal ring damaged or stuck into the stolen goods, etc., can make the pump does not pump oil. To clean the booty or grinding to restore its sealing performance.
(4) The first gearbox can not rotate normally. For example, a serious clutch slippery, clutch pedal in a separate position, the pump lost power, of course, can not rotate.
(5) Low-pressure oil into the large amount of air, air bubbles impede the flow of hydraulic oil, can be seen directly. Release the check valve nut to remove the air.
(6) 108 bearing ring broken, ball off, broken debris stuck in the variable speed gear, the driver did not hear the sound of damage, the plunger will not pump oil. At this point should remove the pump observation, if the 108 bearing is broken, gear oil should be released to completely remove debris, and then replace the 108 bearings.
(7) plunger stuck in the pump body, clutch clutch handle by hand, judging whether the plunger stuck. If the separation is easy, the plunger spring is in compression and the plunger is stuck in the pump body. Plunger stuck for three reasons: ① longer working pressure pump, a larger load, or a long time "empty pump", or with the gap is too small, poor lubrication, high temperature and other reasons can cause the plunger stuck. If the serious injury, should be replaced by a new pump; If the minor injuries, the application of fine abrasive cloth polished to the Department of polished, can continue to use. ② newly installed pump prone to plug the phenomenon of the plunger, which is mainly fixed pump three bolts caused by inconsistent tightening torque, the three bolts can be slightly tightened. Move the pump slightly and tighten the three bolts evenly. ③ more impurities in the hydraulic oil, so that the plunger and pump body surface damage and stuck.
2. Belongs to the second section of fault (1) connecting rod connecting rod with the inner lifting arm broken, connecting rod off, the inner lifting arm can not get power. The diagnosis is: When the hydraulic pump is working normally, lift the outer lifting arm several times by hand and feel whether the inner lifting arm pushes the piston. If there is no sense of force, the lifting arm and the connecting rod can be basically determined to be disconnected. At this point the cover should be disassembled inspection, if it is within the lifting arm and the connecting rod connecting rod break, you can replace a slightly smaller pin, so that the pin does not directly withstand the force, leaving the connecting rod spherical surface and lift arm concave direct contact Power transmission, or pin will continue to break. After connecting the connecting rod and the inner lifting arm to break the pin, the connecting rod spherical surface may directly overhang the edge of the pit of the lifting arm, which is equivalent to lengthening the connecting rod. Pistons can not lift to reach the drain position on time, therefore, the connecting rod may break the inner lifting arm, or even breach the back cover. This failure occurs with a certain noise, once found, should immediately stop, replace the new pieces.
(2) The cylinder and the piston stuck, the hydraulic oil is too dirty, pulling the piston and the cylinder wall; or piston and cylinder liner gap is too small, working time is longer, the temperature is higher, the piston swelled in the cylinder sleeve. Diagnosis is: When the pump is working properly, release the tubing joint between the pump and the cylinder, you can find that there is high pressure oil spray, but the outer lift arm without lifting action. Exclusion method is: decomposition cylinder. If cylinder and piston are damaged seriously, should be replaced with new ones. If the strain is light, use fine emery cloth to polish the injury and re-install.
Two. Heavy load can not be upgraded 1. Belongs to the first section of the fault (1) safety valve to adjust the pressure low, correct safety valve pressure. (2) Plunger and pump body with serious wear and tear, this phenomenon is mainly the hydraulic system using a longer time. The general accumulated working hours up to 1500h, with a small diameter dial gauge, with the maximum gap of not more than 0.03ram. If the clearance is too large, it will affect the amount of pump oil in the plunger, causing oil leakage or air intake. (3) mixed with air in the hydraulic oil should be excluded. (4) safety valve ball sealing surface stained with dirt or its own lax, should remove the safety valve cleaning. (5) other parts have oil spills, especially one-way valve. Check valve body under the plane and the pump body contact between the sealing surface dirt, should be removed. Seal the valve body surface should be polished in a smooth cloth to restore its sealing.
2. Belongs to the second section of the fault (1) the top of the piston seal drain ball leak seal, a serious oil spill, this fault is not easy to judge on the outside, only to break down the cylinder for inspection. (2) piston and cylinder wear serious seal ring is severely damaged or severely damaged, resulting in oil spills, affecting the lifting force. (3) cylinder into the top of the loose tube, causing serious oil spills. If the cylinder screw holes on the slider, should be replaced with a new cylinder.
