1, the cause of abnormal sound of excavator bearings
The rotary bearing of excavator generally works under the condition of large load. The working environment of excavator is bad, and the rotary bearing is prone to failure. The common thing is all kinds of abnormal noise. Abnormal noise refers to loud, unusual, and especially loud noise. When the slewing bearing is idling shortly after leaving the factory, it will produce a uniform sound of rolling steel ball, which is a normal sound. If just installed soon, there is a small noise after a period of rotation and run-in will generally disappear. If the excavator rotary bearing has been abnormal noise, it may be caused by the following reasons:
1. There are foreign bodies in the slewing support
When there are sand particles, iron filings and other foreign bodies in the rotary bearing of excavator, aperiodic vibration will occur, and there will also be rotational inflexibility failure. In this case, before installation, it is necessary to strictly clean the bearing, shaft, seat hole and supporting parts, and remove foreign bodies in lubricant in time; It is important to avoid the use of impure material or embedded plastic cage, should be abnormal noise.
2. Abnormal noise caused by grease problems
The excavator slewing bearing is lubricated by grease, and the abnormal noise is likely to be caused by the lubrication problem. Common reasons include insufficient grease in raceways, uneven grease injection, poor grease quality and aging, and incorrect lubricant selection. To solve this problem, just use the appropriate lubricant, immediately inject, immediately replace the solution.
3. Abnormal noise caused by seal damage
Check whether the seal is worn, because the structure of the excavator rotary bearing seal plays a key role in the seal. When the sealing strip and slewing bearing can not be fully fitted, it is easy to cause grease leakage. In addition, the aging resistance and yellow oil resistance of the sealing material is also a problem to be considered.
4. Abnormal noise caused by cracks, indentation or corrosion
When cracks, indentation and rust appear on the rolling surface of the excavator rotary bearing, periodic vibration like rivet is heard. The wound occurs continuously on the channel, and the wound is hidden on the steel ball. This noise changes with the installation and lubrication conditions. The liberation method is not to hit the bearing or use grease with high viscosity when installing.
5. Serious wear and tear of raceway and rolling body
The abnormal noise in the process of excavator rotation is probably caused by the serious wear of slewing bearing and rolling body. At this time, it is necessary to repair the slewing bearings.
2, the type and cause of excavator rotary bearing failure
1. Type
Excavator slewing bearing is prone to the following two kinds of faults
First, the slewing bearing of excavator often operates under large load and impact conditions, and the working environment is poor. The internal and external oil seals of the slewing bearing wear fast and the grease leaks.
Second, the bottom plate connected with the rotary table and slewing bearing deforms seriously under the condition of partial load. The concentrated action of the load is on a part of the rolling body, and the rolling body, inner seat ring, outer seat ring and rotating motor are damaged.
2. Cause of the fault
① The oil seal is worn out
When the excavator rotates, the outer seat ring and the oil seal rotate relative to the inner seat ring. And the inner seat ring is worn and gradually thinned. After the inner oil seal becomes thinner, the sealing effect decreases, the grease in the slewing bearing room is too much or the working temperature rises, the pressure in the slewing bearing room increases, and the grease leaks from the indoor grease.
② The injection of grease is not uniform
Grease is only injected into the same part of the inner cavity of the slewing bearing. The injection of grease is not uniform, the outer oil seal is extruded and falls off, and a large amount of grease spills out.
(3) The quality of grease is poor
When the quality of the added grease is poor, the temperature of the friction part of the slewing bearing rises, and the grease becomes thin. The grease thus thinned will leak from the outer oil seal.
④ slewing bearing wear
If the excavator has abnormal noise or rotation instability in the process of rotation. The slewing bearing raceway and rolling body are seriously worn, and the gap between the inner and outer seat rings is too large. During the rotation of the slewing bearing. The grease is extruded from the inner and outer oil seal, and the inner and outer oil seal is damaged.
