Excavator fault analysis: Why does the slewing bearing make abnormal noises?

First of all, it needs to be made clear that when the slewing bearing is idling shortly after leaving the factory, it will make a uniform sound of steel balls rolling, which is a normal sound; if it has just been installed, it doesn’t matter if there is a slight abnormal noise, which will generally disappear after a period of rotation and running-in. What we are talking about today is the louder and more special noises, and you need to pay attention when you hear special noises.

1. Uneven mounting surface and loose mounting bolts

When abnormal noise occurs, it is necessary to check whether it is caused by the problem of installation operation. When the unevenness of the mounting surface does not meet the requirements, it will cause the raceway to form a negative gap, thereby generating abnormal noise; in addition, when the pinion meshes poorly, abnormal noise may also occur, which will also cause the failure of broken teeth; in addition, when the mounting bolts are loose, the slewing bearing is elastically deformed, and the deformation position produces a negative gap. It is necessary to check immediately and tighten the bolts as required.

2. There are foreign objects in the slewing bearing

When there are foreign objects such as sand and iron filings inside the slewing bearing, non-periodic vibration will occur, and there will also be a failure of inflexible rotation. When encountering this situation, it is necessary to strictly clean the bearings, shafts, seat holes and matching parts before installation, and remove foreign objects in the lubricant in time; remember to avoid using plastic cages with impure materials or embedded foreign objects, so as to remove the corresponding abnormal noise.

3. Abnormal noise caused by grease problems

The slewing bearing of the excavator is lubricated with grease, and the abnormal noise is likely caused by lubrication problems. Common reasons include lack of grease in the raceway, uneven grease filling, poor grease quality and aging, wrong lubricant selection, etc. To solve this problem, just use the right lubricant, fill it in time, and replace it in time.

4. Abnormal noise caused by damaged sealing strip

Check whether the sealing strip is worn, because the structure of the slewing bearing sealing strip plays a key role in the sealing performance. When the sealing strip and the slewing bearing cannot fit completely, it is easy to cause grease leakage. In addition, the aging resistance and butter resistance of the sealing strip material are also issues that need to be considered.

5. Abnormal noise caused by cracks, indentations or rust

When there are cracks, indentations or rust on the rolling surface of the slewing bearing, periodic vibrations like riveted rivets can be heard. Scars will occur continuously on the groove, and scars will appear and disappear on the steel ball from time to time. Moreover, this noise varies with the installation and lubrication conditions. The solution is not to knock the bearing during installation or use high-viscosity grease.

6. Severe wear of the raceway and rolling element

When the excavator makes abnormal noise during the rotation process, it is likely that the raceway and rolling element of the slewing bearing are severely worn. At this time, the slewing bearing needs to be repaired.