There are many types of ball bearings, each with special features designed for different purposes and to meet specific requirements. The structure of the equipment, dimensions of the parts which will be assembled to the bearing, and the ball bearing application environment and conditions need to be confirmed. Several conditions of the application should be considered as you decide on a ball bearing part number and specification. Additionally, the market is an important factor in your bearing part number and specification selection. Setting an overarching standard for the selection of bearings is difficult, as each type of the bearing has different criteria for application-influencing factors. Therefore, you should always review your selection of bearings according to your application’s specific requirements. Following are a few generic guidelines to help you through some of the factors that influence the selection of ball bearings.
Structure and function of the equipment
The dimensions and performance are required of your application’s ball bearings for your application should be based on an understanding of the structure and function of the equipment involved. The scaling down of equipment has made bearing structure limitations more severe. Even so, we recommend taking into account the items listed below and selecting your ball bearing carefully to achieve the bearing performance that your application requires.
Application environment (temperature, humidity, vibration, dust, etc.)
Your application’s predicted ranges of humidity and temperature should determine your selection of bearing materials, lubricants, and retainer. Vibration conditions determine the proper ball bearing proper preload and lubricant. For applications that involve the presence of dust, this factor should be taken into account when selecting the bearing. In certain bearing operation conditions, the temperature of the ball bearings can sometimes be higher than environmental temperature.
Loads applied to ball bearings
Selecting the bearing dimension, or Part Number, should be based on the magnitude, position, and direction of loads applied to the bearing. The equipment’s structure should be taken into account to determine if excessive loads would be applied to the bearing. If so, it will be necessary to select a larger size bearing or decrease the loads in the application.
Material and dimensions of the shaft and housing
When it comes to choosing the bearing dimensions and tolerances of bore, outer diameter, and width, the decision should be based on dimensions and material of the shaft and housing. Temperature changes will cause fluctuations in bearing internal clearance, and it is important to take this into account. There are differences in linear expansion coefficients between either shaft or housing material and bearing material.
RPM, Rotation Precision, Rotation Ring
Dimensional tolerance, retainer, clearance, preload, and lubricant are selected based on RPM, Rotation Precision, and rotation conditions (continuous/intermittent/back and forth/outer or inner ring rotation).
There are two relevant classifications for torque: starting torque or running torque. For ball bearing applications that require low torque, lubricant selection, fill amount, and retainer material need to be considered carefully.
When low noise level is required for a bearing application, the noise characteristics, lubricants, and preloads of the bearings should be considered. Because improper installation of ball bearings can cause noise levels to increase, it is important to take care during the installation process.
JIS B 1518 / ISO 281 does define rating life for ball bearings, but bearing life can be defined in a variety of ways. The life of a bearing is not only affected by the application requirements, but also by the progress of degradation in performance levels, such as noise, torque, runout, etc. When it comes to bearing life, consideration of the types to consider rating life, noise life, performance life, and lubricant life is also necessary.
Environmental, health, and safety regulations on certain substances have been put into place in recent years. Determining whether your application involves any regulated substances that are harmful to humans or the environment is critical