Analysis And Elimination Of Common Fault Of Chinese Pay Loader Working Device

Analysis And Elimination Of Common Fault Of Chinese Pay Loader Working Device

Date:Jan 29, 2018

Analysis and elimination of common fault of Chinese pay loader working device

1. Slow speed of lifting and collecting bucket

In such a case, we should first check whether the oil level of the fuel tank is too low, resulting in insufficient or empty suction of the high-pressure pump, whether the oil filter is blocked or not, resulting in poor oil return, resulting in low oil level of the tank. Secondly, check whether the gear pump is released or not, so that the volume efficiency of the high-pressure pump can't meet the requirement. Whether the sealing condition of the inlet pipe is good, whether the air enters the system, causes insufficient pressure, and whether the gear pump's inlet and outlet pipe is accurately installed. After checking the hidden trouble of the above parts, check the inner leakage of the arm cylinder and the manipulating valve of the movable arm, the cylinder of the flip bucket and the control valve of the flip bucket.

Through analysis and practice, a simple method for quick diagnosis and troubleshooting is found.

(1) the bucket full load, lifting to the limit position; the movable arm lever is placed in position, and the engine flameout, the hydraulic pump to stop the oil boom, observe the sinking speed; then the arm lever in the raised position, if the boom sinking speed significantly accelerated in the causes of leakage from the boom control valve. Similarly, for the weak phenomenon of bucket hopper, a similar method can also be used to determine the expansion condition of tipping bucket according to the joystick's position in the middle and backward position.

(2) check whether the piston seal ring of the arm cylinder is damaged. The boom cylinder shrinkage in the end, and then remove the non rod chamber oil pipe, the boom cylinder rod chamber to oil filled, if non rod chamber oil mouth has a large number of oil leakage (leakage normal should be less than or equal to 30ml/min), indicating the piston seal ring is damaged, should be replaced immediately.

(3) if the O type sealing ring of the distribution valve is aged, deformed or worn, the valve rod is partially corroded, causing the seal surface to be damaged, the leakage of the distribution valve will be caused. You should replace the O ring, if the stem ends can be corroded part of serious corrosion, wear off, and then make the brazing, restore to the original diameter I polished. If the distribution valve's spool and valve sleeve wear seriously, it will cause internal leakage. At this time, the distributor valve should be replaced. If conditions permit, chromium plating on the spool surface can also be made, and then match with the valve sleeve to make the gap match 0.006 to 0.012mm and no stuck.

(4) this kind of problem will occur when the opening pressure of the pilot safety valve is too low. At this time, we can not blindly adjust the pressure regulating screw of the total safety valve. We should check the safety valve to see whether the pilot valve spring is broken, whether the pilot valve seal is good, whether the main valve core is jammed and whether the main valve core damping hole is blocked. If there is no problem above, the opening pressure of the safety valve should be adjusted. The pressure adjustment method: first unscrew the plug valve on the distribution, connect the pressure gauge, and then start the engine and the speed control in 1800r/min, and then the rotating bucket valve placed in position, the arm up to the limit position, the system pressure, then adjust the pressure regulating screw until the pressure readings reach the specified value.

2. The lifting of the arm is normal, but the bucket is slow.

The main reasons for the failure are the bucket cylinder, the non rod cavity of the bucket oil cylinder and the two overload valves with the rod cavity should be in accordance with the regulations. The pressure detection process is as follows: in pressure connected with the pressure gauge will double bucket control valve is placed in position, to lift or lower the boom, when the rod over the dead center, bucket oil cylinder rod cavity and a non rod chamber pressure should be established, the tipping bucket cylinder piston rod movement when the pressure gauge pressure is shown as the overload valve set pressure. If the pressure is lower than that of the factory, the reason may be as follows:

(1) there are internal leakage faults in the bucket cylinder, and the elimination method is the same as that in the cylinder of the moving arm.

(2) the main valve core of the overturn cylinder overload valve has impurity particles, and the main valve core is stuck to die, and the main valve core is in the constant open state, forming a fault point.

At this time, we should clear the impurities, check the state of the parts in the valve and adjust the gap between the valve stem and the valve body, and the normal clearance should be 0.06 ~ 0.012mm.

3. Jitter of lifting and hopping

The reasons and methods of troubleshooting are as follows:

(1) lack of oil quantity, make the work pressure unstable, should add the hydraulic oil.

(2) the sealing of the oil road interface is not good, so that the air enters the system, the work pressure is unstable, and the interface of the oil road should be checked.

(3) a large number of air bubbles are mixed in the oil liquid to make the oil mixed with air into a compressible object. We should eliminate the tight seal in the low pressure oil road and drain the oil mixed with the air.

(4) the locking nut of the piston rod of the hydraulic cylinder is loose, causing the piston rod to move in the hydraulic cylinder. The hydraulic cylinder should be disassembled and the nut is locked.

(5) the opening pressure of the total safety valve is unstable, which causes the pressure of high pressure oil to change and cause the jitter. The pressure regulating spring should be checked and the opening pressure should be adjusted.

(6) the amount of discharge in the cylinder and the double arm cylinder is unequal, causing the fluctuation of the flow and causing the jitter. It is necessary to remove the faults in the cylinder of the bucket and the cylinder of the moving arm. If the check is no problem, and the piston rod has a large area of szlama, should be removed by grinding, and hard chrome plating 0.05mm, if worn rod diameter is too small, may be appropriate to increase the thickness of the guide sleeve.


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