What factors influence bearing selection? Below, Shanghai SKF spherical roller bearing manufacturers provide a detailed explanation!

1. Installation Space and Bearing Type

The design space available for rolling bearings and their peripherals is limited. Bearing type and dimensions must be selected within these constraints. Mechanical designs typically commence by determining the shaft diameter, hence bearing selection is often based on the inner diameter. Rolling bearings feature numerous standardised size series and structural configurations, enabling selection of the most suitable type.

2. Load and Bearing Type

Comparing bearing types reveals their fundamental rated load capacity and derived axial load capability, as illustrated below. Within the same size series, roller bearings generally exhibit higher load capacity than ball bearings, making them suitable for applications involving impact loads.

3. Maximum Speed and Bearing Type

The maximum permissible speed for rolling bearings varies not only by bearing type but also by cage design, material, load, lubrication method, and cooling conditions. Under typical oil bath lubrication, bearings are categorised by maximum speed in descending order.

4. Misalignment of Inner and Outer Rings and Bearing Type

Misalignment between the inner and outer rings may occur due to shaft deflection under load, poor shaft or housing precision, or installation errors. The permissible misalignment angle varies by bearing type and operating conditions, typically being less than 1.0012 radians (4'). Where significant misalignment between inner and outer rings is anticipated, select self-aligning bearing types such as self-aligning ball bearings, spherical roller bearings, or spherical outer ring ball bearings with housing.

5. Rigidity and Bearing Type

When rolling bearings bear loads, elastic deformation occurs at the contact points between rolling elements and raceways. Bearing stiffness is determined by the ratio of applied load to the elastic deformation of the inner and outer rings and rolling elements. Applications such as machine tool spindles require enhanced shaft-bearing stiffness. Consequently, roller bearings—which exhibit lower deformation ratios than ball bearings under load—are frequently selected. Furthermore, applying preload to achieve negative clearance enhances bearing stiffness. This technique is suitable for angular contact ball bearings, tapered roller bearings, and similar types.

6. Noise, Torque and Bearing Type

Rolling bearings manufactured using precision machining techniques exhibit low noise and torque. Deep groove ball bearings, cylindrical roller bearings and similar types have specified noise grades according to their application. High-precision miniature ball bearings have defined starting torque specifications. For instruments requiring low noise and low torque, such as electric motors and measuring instruments, deep groove ball bearings are suitable.

7. Rotational Precision and Bearing Type

Applications demanding high rotational runout precision, such as machine tool spindles, or high rotational speeds like in superchargers, should employ high-precision bearings of grades 5, 4, or 2. Rotational precision specifications for rolling bearings vary by parameter and differ across bearing types. Consequently, deep groove ball bearings, angular contact ball bearings, and cylindrical roller bearings are frequently selected for applications requiring high rotational accuracy.

8. Installation, Removal and Bearing Type

Cylindrical roller bearings, needle roller bearings, and tapered roller bearings feature separable inner and outer rings, facilitating installation and removal. Where bearings require frequent disassembly and reassembly for periodic inspection, these structural types are particularly suitable. Self-aligning ball bearings with tapered bores and self-aligning roller bearings (small sizes) employ bushings, enabling relatively straightforward disassembly and installation.