According to the different causes of the abnormal noise of the rotary mechanism caused by the mechanical fault, the abnormal noise of the rotary mechanism of the hydraulic excavator can be further divided into the abnormal noise of the rotary support, the abnormal noise of the rotary motor and the meshing noise of the inner teeth of the rotary support and the pinion of the rotary motor.
Noise from slewing
The rotary support used in hydraulic excavator is mostly single row four point contact ball inner tooth rotary support, which is mainly composed of outer ring, inner ring, rolling body and sealing strip. The abnormal noise of slewing bearing is caused by the negative gap between the raceway and the rolling body composed of the inner ring and the outer ring of the slewing bearing. The negative gap between the raceway and the rolling body is caused by different reasons in the manufacture, installation and use of the slewing support.
The problems in the installation of slewing support may lead to elastic deformation of slewing support and negative gap in deformation position, which may lead to abnormal noise of slewing support. The abnormal noise caused by bolt loosening or insufficient pretightening force can be eliminated by pretightening the bolt to the specified pretightening force in turn. The abnormal noise caused by the slewing support mounting surface of the cargo chassis does not meet the flatness requirement can be solved by replacing or trimming the mounting surface of the chassis and chassis.
The lubrication problems of slewing support occur in the first off line of slewing support or for a long time without maintenance. The lack of grease in the slewing bearing raceway leads to the abnormal noise due to the collision between the internal rolling body of the slewing bearing and the spacer, which can be eliminated after the grease is added in time. The mixing of sand and iron chips in the slewing bearing raceway often occurs after the breakage of the slewing bearing sealing tape, which leads to the difficulty of rotating the slewing bearing, the abnormal noise, and the acceleration of the wear of the slewing bearing raceway and the rolling body, which leads to the damage of the slewing bearing. If the slewing support is not damaged, only the foreign body can be removed to eliminate the abnormal noise.
After long time use of rotary support, due to poor quality or lack of maintenance of components, the slewing support will be damaged. After the slewing support is damaged, the slewing support should be removed for replacement or maintenance. The abnormal noise caused by pitting and stripping of the rotary bearing rolling body can be eliminated by replacing the rolling body. The abnormal noise caused by pitting and stripping of the rotary bearing raceway can be solved by welding the peeling or pitting place. After welding, the polishing machine can be used to smooth the welding place, and the normal surface height of the raceway can be gradually repaired with the gold-phase sand cloth. When the stripping and pitting of the raceway are serious, the large rolling body can also be selected, and then the raceway can be repaired according to the larger rolling body size.