The excavator makes a rattling sound irregularly when it is slewing under heavy load. Check the slewing motor with a sonic detector, install a pressure gauge on the main pump, and when the excavator slews under heavy load, the gauge needle swings, and the pressure value then decreases whenever a rattling sound is made. The following is method of checking.
Step 1: Safety Isolation and Preliminary Check
First, park the excavator in an open area to ensure that the surroundings are safe. Subsequently, fully extend the movable arm and bucket bar, raise the bucket to a height of approximately 1m above the ground, and turn off the engine to relieve residual pressure in the system. Keeping the slewing motor oil line connection intact, we removed the bolts holding the motor in place, partially separated the motor from the slewing gearbox, and secured it after ensuring that there was some clearance between the main shaft and the center tooth sleeve. Then, the engine was restarted and the motor was idled by the hidden corpse operator. As the motor was separated from the reducer at this time, it operated smoothly without abnormal sound, thus confirming that the slewing motor itself was not faulty. Afterwards, we completely removed the motor from the excavator.
Step 2: Located The Source of The Noise
In order to determine the specific location of the abnormal noise, we pushed the bucket by human power(making sure that the bucket was off the ground), so that the excavator rotated left and right. Through the hearing judgment of the personnel on board, we found that the noise comes from both the rotary reducer and the rotary gear ring. For further confirmation, we removed the reducer and disassembled it for inspection, and found that the bearing at the main shaft end was damage, which was the cause of the noise in that area.
Step 3: Deeper Inspection and Discovery
Although the problem with the gearhead had been found, there was still a strange noise from the slewing ring. Therefore, we continued to dismantle the gear ring for detailed inspection, and found that hardened layer of the rolling surface of the disk had been peeled off and skinned, which was the direct cause of the ring’s noise.
Step 4: Professional Repair and Reinstallation
For the problem of slewing ring, we sent it to a professional repair shop for treatment. According to the increased size of the ball, the workshop repaired the raceway accordingly, and re-quenched it. After the repair, we reinstalled the slewing ring on the excavator and started the machine for test run, confirming that the noise was eliminated and the excavator returned to normal working condition.
Post time: Oct-20-2024