The life of the slewing ring raceway is determined by the quality of its own products and subsequent maintenance. It is even considered “three-point quality and seven-point maintenance”. The following phenomena generally occur after the raceway is damaged and failed: large gaps, oil leakage, jamming, abnormal noise, iron powder and even iron pieces on the raceway, etc. There are many reasons for the failure of the bearing. Today, the editor will introduce four common failures of the slewing ring raceway. For everyone to learn and understand.
1. The raceway is worn
The relative sliding friction between the surfaces causes the metal of the working surface to wear out continuously and cause failure. Abrasion will cause an increase in the fit clearance and a change in the shape of the raceway surface, and it will also affect the lubricating function of the lubricant, causing the bearing to lose rotation accuracy or even fail to operate normally. Raceway wear is divided into normal wear and abnormal wear. Normal wear and tear is a process in which the gap gradually increases during the full life cycle to complete the task of the full life cycle. Abnormal wear has manufacturing problems, standard parts problems, grease problems and later maintenance problems. The first three problems are related to the slewing bearing manufacturer, and the fourth situation is the problem of the equipment user.
2, plastic deformation of raceway
Under the action of external force, the partial plastic flow or overall deformation of the surface of the part, such as the deformation of the raceway or the torsion and warpage of the cage, causes the failure of the slewing bearing to fail to work normally, which is called plastic deformation failure. This situation often occurs after a period of use. At this time, the high-hardness layer has been mostly worn out. After the load and friction are suddenly increased, the metal inside and outside the raceway is squeezed into a pile. The steel with high hardenability should be used instead.
3, the surface of the raceway peels off
The main reason for the surface spalling of the slewing bearing raceway is that the hardened layer is too thin and the hardness transition zone is too narrow. There are many reasons for contact fatigue failure. It may be that excessive axial load, poor lubrication, poor alignment, excessive impact load during installation, etc. can cause contact fatigue failure of the bearing. A lower frequency intermediate frequency equipment should be used to deepen the hardened layer. At the same time, it is necessary to appropriately increase the quenching and tempering hardness to reduce the hardness gradient of the raceway section.
4, raceway corrosion and pitting
The metal surface undergoes a chemical or electrochemical reaction with the environmental medium, and the surface damage caused is called corrosion failure. Corrosion is divided into three categories: chemical corrosion, electric corrosion, and fretting corrosion, which is mainly manifested as the corrosion of the internal bearing surface. Factors such as the intrusion of corrosive media, the condensation of moisture in the air, the sparks generated when the current passes, and the fretting vibrations can all cause corrosion failure of the slewing ring raceway. Pitting corrosion mainly occurs on the raceway treated by quenching and tempering. The reason is low hardness and unreasonable design of the raceway structure, causing sliding friction and contact fatigue stress, causing defects such as pitting corrosion and indentation.
The above is an introduction to the four forms of common slewing ring failures. In order to avoid such failures, reasonable and effective maintenance of the slewing ring should be carried out on a regular basis. This will not only reduce the occurrence of failures, but also increase the number of slewing rings. Service life.