Basic Requirements for Bearing Selection and Application

Basic Requirements for Bearing Selection and Application

A complete bearing configuration involves not only bearings, but also other related components, such as shafts and bearing seats, all of which belong to the main components of the whole bearing system. In addition, lubricants and seals are also key components. To give full play to the proper performance of a bearing, it is necessary to use appropriate lubricants and an effective sealing system to prevent pollutants from entering the bearing. After years of verification, cleanliness has a significant impact on the working life of bearings, which is also the main reason why manufacturers of bearings extended their business scope to lubricating and sealing products many years ago. Ms. Today, I would like to talk briefly with you about the problems that should be paid attention to in bearing configuration.


Problems to be Concerned about Bearing Configuration

To design an ideal bearing configuration, we need to do the following things, of course, the motor bearing configuration is no exception.

-Choose the appropriate bearing type.

-Determine the appropriate bearing size.

-Structure and design of other components in configuration.

-Appropriate tolerance fit and bearing clearance or preloading.

-Fixed bearing mode.

-Proper sealing system.

-Types and dosages of lubricants.

-Installation and disassembly methods, etc.


Each of the above will affect the performance, reliability and cost-effectiveness of the entire bearing configuration. The time and workload involved in selecting bearings depends on whether the user has experience in similar bearing configurations. If these experiences are lacking, there are special requirements in application, or the cost of bearing configuration and other related factors need to be considered in detail, more detailed work, including more accurate calculation or testing, must be done in the selection of the type.


When choosing the dimensions of bearings, according to the load acting on the bearings and the requirements of working life and reliability, the required bearings can be preliminarily determined according to the rated load of the bearings. The basic rated dynamic load C and basic rated static load Co are listed in the product table. The condition of bearing static load and dynamic load must be checked independently. When checking the dynamic load, the load spectrum which is most in line with the actual situation should be used for checking calculation, including the maximum load that may occur. Static load refers not only to the load acting on bearings at rest or at very low speed (n < 10r/min), but also to the safety factor of static load under heavy impact load (load acting in a very short time).


System Method for Selecting Bearings and Reliability of Bearings

The stresses considered in the formula of bearing rated life include stresses caused by external forces, stresses caused by surface condition, lubrication condition and rolling contact surface in kinematics. By considering the effect of these stresses on bearing life, the performance and performance of bearings can be predicted more accurately in specific applications.


Generally speaking, the metal fatigue of rolling contact surface is the main cause of rolling bearing damage. Therefore, for a specific application, the raceway fatigue is enough to select the appropriate rolling bearing and its size. The international standard IS0281 is based on the metal fatigue of rolling contact surface. But more importantly, the whole set of bearings should be regarded as a system, in which the possible components, such as cages, lubricants and seals, play the same role in the durability of bearings, and in some cases play a leading role. In theory, when all components reach the same life, it is the best working life.


That is to say, if the actual working life of the bearing is to reach the calculated life, the working life of its components must also reach the calculated life of the bearing at least. Key components include cages, seals and lubricants. In practical application, metal fatigue is still the most important factor.