The previous article explained the first three common faults of the hydraulic circuit of the loader working device. In this article, we will look at the last three faults.
Fault phenomenon 4: The settlement of the boom hydraulic cylinder is too large (the boom is dropped)
Reason analysis:
Lift the fully loaded bucket and the multi-way valve is in the neutral position. At this time, the sinking distance of the boom hydraulic cylinder piston rod is the settlement amount. This machine requires that when the bucket is fully loaded and raised to the highest position for 30 minutes, the sinkage should not exceed 10mm. Excessive settlement not only affects productivity, but also affects the accuracy of work equipment operations, and sometimes even causes accidents.
Causes of boom hydraulic cylinder settlement:
1) The spool of the multi-channel reversing valve is not in the neutral position, and the oil circuit cannot be closed, causing the arm to drop.
2) The gap between the valve core and the valve body hole of the multi-way reversing valve is too large, and the seal is damaged, causing large internal leakage.
3) The piston seal of the boom hydraulic cylinder fails, the piston becomes loose, and the cylinder barrel is strained.
Troubleshooting:
Check the reason why the multi-way reversing valve cannot reach the neutral position and eliminate it; check the gap between the multi-way reversing valve valve core and the valve body hole, ensure that the gap is within the repair limit of 0.04mm, replace the seal; replace the boom hydraulic cylinder piston seal ring, tighten the piston, and inspect the cylinder; check the pipelines and pipe joints, and deal with any leaks promptly.
Fault phenomenon 5: Drop bucket
Reason analysis:
When the loader is operating, the bucket reversing valve returns to the neutral position after the bucket is retracted, and the bucket will suddenly flip down and fall. The reasons for bucket falling are: 1) The bucket reversing valve is not in the neutral position and the oil circuit cannot be closed.
2) The seal of the bucket reversing valve is damaged, the gap between the valve core and the valve body hole is too large, and the leakage is large.
3) The seal of the rodless cavity double-acting safety valve of the bucket cylinder is damaged or stuck, and the overload pressure is too low. 4) The sealing ring of the bucket hydraulic cylinder is damaged, severely worn, and the cylinder barrel is strained.
Troubleshooting:
Clean the double-acting safety valve, replace the sealing ring, and adjust the overload pressure. For other troubleshooting methods, please refer to Problem 3.
Fault phenomenon 6: Oil temperature is too high
Cause analysis and troubleshooting methods:
The main reasons for the oil temperature being too high are: the ambient temperature is too high and the system works continuously for a long time; the system works under high pressure and the relief valve is frequently opened; the relief valve setting pressure is too high; there is friction inside the hydraulic pump; and improper selection of hydraulic oil Or deteriorated; insufficient oil. Check to determine the cause of high oil temperature and eliminate it.
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Post time: Oct-15-2024