In order to give full play to the original performance of the seated rolling bearing and maintain it for a long time, it is important to choose a shaft suitable for the use conditions. The shaft should have sufficient rigidity without bending, scratches, burrs, etc. Accuracy of the shaft: the dimensional tolerance of the shaft used for cylindrical bore bearings with stop screws. Cylindrical bore bearings with stop screws use tolerance zones that can form a relatively loose fit for easy installation. For the fit between the inner ring of the bearing and the shaft, the higher the speed of the bearing, the smaller the fit clearance should be. The approximate standards for the rotational speed of the cylindrical bore bearing with set screw and the tolerance zone of the shaft used are shown in Table 9.1. In the case of heavy load (Pr /Cr>0.12) and vibration and impact of cylindrical bore bearings with stop screws, in order to prevent creep and peeling of the mating surface of the bearing inner ring and the shaft, the shaft used can be used for comparison. Tight fit tolerance zone. The approximate standard of the tolerance zone of the shaft used when forming a relatively tight fit with a cylindrical bore bearing with a set screw is shown in Table 9.2. In addition, the recommended values u200bu200bof roundness and cylindricity of the shaft are shown in Table 9.3. Dimensional tolerance of the shaft used for cylindrical bore bearings with set screws (recommended) (for clearance fit or transition fit) Note) dn u003d d (bearing inner diameter, mm) × n (speed, min-1) with set screws The dimensional tolerance (recommended) of the shaft used in the cylindrical bore bearing (in transitional fit or interference fit) The recommended accuracy of the shaft used in the seated rolling bearing. The dimensional tolerance of the shaft used in the blower bearing (with a stop screw cylindrical hole) The blower bearing (special symbol S5) works in a high-speed rotating state, and at the same time, in order to suppress vibration and noise during operation, the inner part of the bearing is moved The clearance (C2) and the machining accuracy of the bearing have been improved by one level. Therefore, the tolerance zone shown in Table 9.4 is recommended for the shaft used in the blower bearing (with a set screw cylindrical hole). The dimensional tolerance of the shaft used in the blower bearing (with a set screw cylindrical hole) (recommended) The dimensional tolerance of the shaft used in the tapered bore bearing (with fasteners) The tapered bore bearing uses fasteners to fix the bearing on the shaft. Therefore, the shaft selected for ease of installation adopts a tolerance zone that can form a relatively loose fit. The dimensional tolerances of shafts used in tapered bore bearings (with fasteners) are shown in Table 9.5. The dimensional tolerance of the shaft used in the tapered bore bearing (with fasteners) (recommended) The dimensional tolerance of the shaft used in the cylindrical bore bearing with eccentric fixing ring If the fit clearance is large, there will be the risk of the shaft being installed tilted. Therefore, it is recommended that the shaft used in the cylindrical bore bearing with eccentric fixed ring and the shaft used in the blower bearing (special symbol S5) have the same tolerance zone (h5 or j5) (refer to Table 9.4). Stepped shaft size: When using cylindrical bore bearings in applications where the axial load is large and intense vibrations and shocks exist, use a stepped shaft and tighten the inner ring of the bearing with a nut. The shoulder diameter and corner fillet radius of the stepped shaft are shown in Table 9.6. The shoulder diameter of the stepped shaft and the fillet radius of the corner (recommended).