What are the maintenance methods for high-pressure hydraulic cylinders?

The maintenance methods and fault causes of high-pressure hydraulic cylinders mainly include the following points. These are summarized by our maintenance masters’ many years of maintenance experience. We hope they will be helpful to everyone. Common faults of the high-pressure cylinder hydraulic system include: jumping during the lifting process, forks, self-lowering, mast self-tilting, lifting capacity not reaching the rated value, slow lifting speed, etc. Here’s how you can fix it.

1.The gantry jumped during the lifting process. The cause of the failure was that there was air in the lifting hydraulic cylinder, the performance of the gear pump was poor, the reversing valve was not flexible, and the oil was not clean. Maintenance method: First, loosen the bleed plug on the lifting hydraulic cylinder to release the air in the lifting hydraulic cylinder; check the cleanliness of the forklift oil. If the runout still cannot be eliminated, check the working condition of the reversing valve and gear pump. If they still work poorly, repair or replace them.

2. The fork descends on its own and the mast tilts forward on its own. Phenomenon, after the fork is raised, it automatically descends or the mast automatically tilts forward. The cause of the failure is that the distribution valve, valve core and valve body are severely worn, and the oil automatically flows back to the tank; there is leakage in the hydraulic system; the sealing ring of the lifting and tilting hydraulic cylinder is damaged, causing the front and rear chambers to communicate; the one-way speed limit valve is damaged. The maintenance method is as follows: First, check whether there are leaks in the hydraulic components and connecting pipelines, and if so, repair them. If only the fork comes down on its own, check the one-way speed limiter and reversing valve. It would be nice if the tilt hydraulic cylinder tilted forward on its own. The working condition of the tilt cylinder sealing ring or reversing valve should be checked. If there is any damage, it should be repaired or replaced.

3. The lifting capacity cannot reach the rated value. Phenomenon, the lifting weight is low and cannot reach the rated value. The cause of this failure is that the gear pump is damaged or leaking; the safety valve pressure is too low; the oil pipe or lifting hydraulic cylinder is leaking; the lifting hydraulic cylinder is deformed or damaged; the fuel tank is short of oil. Maintenance method: First check whether the hydraulic oil tank is short of oil; check whether there is oil leakage in each component, find out the cause and eliminate it; check whether the lifting hydraulic cylinder is deformed; check and adjust the pressure of the safety valve.

4. The lifting speed is very slow, which means that the fork is lifted too slowly. Cause of failure: Insufficient oil supply to the gear pump; failure of the safety valve. The lifting hydraulic cylinder is severely worn, causing the matching gap between the valve core and the valve body to be too large; there is air in the system; and the system is leaking oil. Maintenance method: First check each joint, sealing element pad and structure for oil leakage. If so, replace it; deflate the system. If it cannot be ruled out, disassemble and check the working condition of the lifting hydraulic cylinder, gear pump and safety valve. If it does not meet the technical requirements, repair or replace it.