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Solutions to common problems of crane slewing mechanism

01-06, 2023 / in Bearing Knowledge / by LDB

For hydraulic cranes, the slewing drive and motion control of the slewing mechanism mainly depend on the hydraulic system. Therefore, the common faults of the slewing mechanism are firstly related to the hydraulic system. The slewing mechanism is composed of three parts: the support device, the slewing drive device and the turntable. Its important mechanical part, the slewing support, is an important force-bearing part. It not only bears the weight of the slewing part of the crane, but also bears the vertical force of the lifting load. and overturning moment forces.

In the process of use, there must be wear and tear, and the performance of related mechanical parts will gradually deteriorate or even be damaged. Therefore, common failures of the slewing mechanism are also related to the mechanical part. Accordingly, crane failure analysis can generally start from two aspects: mechanical failure and hydraulic system failure. According to the relevant staff, the common faults of the slewing mechanism mainly include excessive clearance of the slewing bearing (wild movement), slow (weak) or immobile movement of the slewing system, abnormal system pressure, oil leakage, and failure to lock the slewing brake valve, etc. .

Weak or unable to rotate (system pressure is normal)

1. The hydraulic motor fails and the power cannot be output normally. Repair or replace it.

2. The reducer breaks down and affects the power transmission, check and adjust.

3. In case of overload, the lifting capacity must be checked again to avoid overload.

4. The overflow valve and manual control valve are faulty, check and adjust.

Cannot rotate (system pressure is normal)

1. The gear or worm gear or worm of the slewing reducer is damaged, check and repair.

2. The hydraulic motor plunger or bearing is stuck or severely worn, check and repair.

3. The output shaft of the hydraulic motor is broken and replaced with a new one.

slewing drive

Swing hydraulic system pressure is low

1. Fault phenomenon

If the crane is unloaded or lightly loaded, the sound and speed of its rotation are normal, but when the crane is heavily loaded, it will be difficult to rotate or even unable to rotate.

2. Cause of failure

The possible reasons for this phenomenon are: low pressure of the relief valve of the rotary hydraulic system, wear of the hydraulic motor, serious internal leakage or low pressure setting of the control valve, severe wear of the valve stem of the control valve, large internal leakage, and pressure loss.

3. Troubleshooting

The troubleshooting method is to adjust first. There are two adjustments: one is to adjust when the rotation is stopped under load, until the rotation is normal under heavy load; the other is to use a pressure gauge to readjust the pressure of the relief valve according to the requirements of the instruction manual. Pressure (the size of the rotary pressure is related to the model); followed by the maintenance of the hydraulic motor and the control valve, and the replacement of worn parts.

The clearance of the slewing bearing is too large (wild movement)

1. Reason: The worm gear of the slewing reducer, the driving gear and the slewing bearing gear are seriously worn.

2. Elimination method: check the clearance with a dial indicator, if it is too large, repair the slewing bearing and replace the relevant parts.

slewing bearing

Oil spill

If the joint surface of the relevant hydraulic components leaks oil, it should be removed for cleaning, and the joint surface should be ground with oil stone or fine sandpaper, and if possible, it can be processed with a grinder; if the threaded connection of the pipeline is loose, it should be tightened; the seal The damaged ones can be replaced; if the casing of the hydraulic component leaks oil, the casing or components must be replaced.

The above are the common problems of the crane slewing mechanism and the corresponding solutions. In actual operation, if you encounter a fault or problem, you must do a good job of troubleshooting and then take the corresponding solution.

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