The selection of rolling bearing dimensions is a critical aspect of mechanical design, requiring a comprehensive consideration of factors such as type, load, speed, lifespan, and installation space. The following is a systematic selection process and key points:

1. Determining the Bearing Type Select the bearing type based on the application scenario: Deep groove ball bearings are suitable for applications with primarily radial loads and medium to low speeds. Cylindrical roller bearings are used to handle large radial loads but are not resistant to axial forces. Angular contact ball bearings can withstand composite loads and must be used in pairs. Taper roller bearings can simultaneously support large radial and axial loads. Thrust bearings are designed for pure axial loads.

2. Basic Concepts of Bearing Lifespan Lifespan: The number of revolutions or operating hours at a constant speed before the first sign of fatigue expansion appears. Reliability: The percentage of rolling bearings that reach or exceed the specified lifespan. Rated Life: The predicted lifespan based on the basic rated dynamic load in the radial or axial direction. Basic Rated Life: The total number of revolutions that 90% of bearings will not experience rolling fatigue spalling. Modified Rated Life: The lifespan considered under non-standard conditions. Median Life: The lifespan reached by 50% of the bearings. Static Load and Dynamic Load: These refer to the loads the bearing bears when it is relatively stationary or rotating. Theoretical Radial and Axial Basic Rated Dynamic Load (Cr, Ca): The constant radial or axial load that the bearing can theoretically withstand. Equivalent Radial and Axial Dynamic Load (Pr, Pa): The equivalent radial or axial load derived from composite loads. Theoretical Radial and Axial Basic Rated Static Load (Cor, C0a): The maximum radial or axial load that the bearing can withstand when stationary.

3. Selection of Bearing Dimensions: Calculate the equivalent dynamic load (P) based on the radial load (Fr), axial load (Fa), and bearing coefficient. Calculate the 90% reliability life (L10) using the basic rated life formula, converting it to hours. Verify static load: For low-speed or slowly swinging bearings, select the size based on the rated static load to prevent plastic deformation. Size limitations: The inner diameter (d) is determined by the shaft diameter, while the outer diameter (D) and width (B) are influenced by installation space, bearing capacity, and axial clearance. Other factors: Consider speed limits, lubrication methods, precision grades, and environmental conditions. Design process example: Select bearings, calculate life, verify static load, and adjust parameters. Tools and standards: Refer to bearing manufacturer samples, international standards, and software for complex load analysis. By following these steps, you can scientifically select bearing dimensions that meet performance, life, and economic requirements. In practical applications, combine engineering experience and consult bearing suppliers when necessary.