If the left and right directions cannot rotate, first check whether the positioning pin of the slewing platform has been pulled out. Pull out the platform locating pin before turning. If the positioning pin of the platform has been pulled out, it still cannot swing left and right. At this time, the machine can be started to make the stick and bucket cylinder fully extend, and the bucket is about 1.5 m above the ground before stopping. When the pilot handle is not operated, the staff pushes the bucket along the platform swing direction. At this time, if the platform can rotate at a small angle, it means that the rotary reducer is not damaged, but other faults cause the platform to not rotate left and right. If the platform cannot swing when pushing the bucket, the fault is caused by the damage of the swing reducer. For this, the slewing reducer shall be disassembled for troubleshooting. If the platform cannot swing left and right, if it is not caused by the reducer, the following sequence shall be followed for troubleshooting.
1. Check whether the pilot valve core controlling the rotation can be pressed in place or blocked. If the swing pilot valve element cannot be pressed in place, it shall be repaired or replaced. If the pilot valve core is blocked by foreign matters, the foreign matters shall be removed so that the pilot valve core can move up and down freely.
2. Check whether the rotary brake valve is intact and whether the rotary brake mechanism is properly adjusted. If the slewing brake valve is damaged or the slewing brake mechanism is improperly adjusted, the slewing reducer is always in the braking state, and the platform cannot swing left and right. At this time, the slewing brake valve shall be repaired or the slewing brake mechanism shall be properly adjusted.
3. Check whether the rotary reversing valve rod of the multi way valve can be flexibly reversed. If flexible reversing is not possible, it may be caused by the following three reasons.
1) The return spring of the rotary reversing valve rod is broken.
2) The rotary reversing valve rod is stuck or jammed by foreign matters.
3) The pressure entering the pilot control chamber of the rotary reversing valve rod is small, which is not enough to make the valve rod flexible reversing.
4. Measure whether the oil inlet pressure of swing motor is normal. If the inlet pressure is always low or there is no pressure, it may be caused by the following reasons.
1) The overflow pressure of the corresponding main relief valve is low. At this time, adjust the corresponding main safety valve to make its pressure reach the specified value. If the main safety valve fails, repair or replace the corresponding main safety valve, and adjust the pressure to the specified value.
2) The overflow pressure of the rotary secondary relief valve is low. The following situations exist.
①. The performance of the rotary secondary relief valve is good, but the pressure adjustment value is low. The overflow pressure shall be adjusted to the specified value.
② The tightening torque of the rotary secondary relief valve is not enough. Tighten it to the specified torque.
③. Rotary secondary relief valve fails. The secondary overflow valve shall be repaired or replaced, and its overflow pressure shall be adjusted according to the specified value.
④ The valve body of the rotary secondary relief valve is damaged, so that the oil in the high and low pressure chambers is connected. Damaged valve bodies should be replaced.
3) The clearance between the rotary control valve rod and the valve body of the multi way directional valve is too large, causing serious internal leakage.
5. If the platform still cannot swing when there is high pressure at the oil inlet of the swing motor. The maintenance personnel shall touch the motor oil return pipe. If there is no oil flow in the pipe and the motor vibration is felt, it can be judged that the motor is damaged internally. If the maintenance personnel feel that there is oil flow in the return pipe of the hydraulic motor, and the platform still cannot swing, it may be caused by the following reasons.
1) The output journal of the swing hydraulic motor is broken. Replace or repair the hydraulic motor.
2) Splines in the input shaft of the reducer are sheared. Damaged parts shall be replaced.
3) The slewing ring is worn because it has not been greased for a long time. Grease should be added to make it better lubricated.
4) The slewing ring isolator or steel ball is damaged and fixed. The damaged parts shall be replaced and lubricated.
