The design of the base The rigidity of the base and the flatness of the mounting surface When the rigidity of the base of the mounted rolling bearing is low or the flatness of the mounting surface is poor, vibration and abnormal sound will be generated during the operation of the mounted bearing, which may cause early damage. In addition, there is a risk of reducing the strength of the bearing housing. Therefore, the base on which the seated bearing is installed should have sufficient rigidity, and the mounting surface must be machined to a precision that does not cause the bearing and the bearing housing to deform. The recommended value of the flatness of the mounting surface of the base installed with a seated rolling bearing is shown in Figure 9.3. Mounting hole with ring seat bearing The ring seat bearing is directly installed in the cylindrical hole of the base as a free end component. Under general conditions of use, the tolerance zone for installing cylindrical bores with ring seat bearings is selected as H7. When the shaft and bearing are used at high temperature, the tolerance zone of the cylindrical hole of the base is selected as G7. In applications where there is vibration and shock, it is recommended to use a tolerance zone with a small clearance between the cylindrical hole of the base and the bearing with a seat. The dimensional tolerance of the cylindrical hole for mounting the base with ring seat bearing is shown in Table 9.8. Dimensional tolerance of cylindrical hole for mounting of bearing with ring seat (recommended) Installation related dimensions of bearing with slider seat The bearing with slider seat is installed between the two guide rails on the side of the base, and the support position of the shaft center can be adjusted by adjusting the bolt. The dimension table of the guide rail, adjusting bolt and round nut for mounting the bearing with slider seat on the base is shown in Table 9.9. The vertical seat, square seat and diamond seat bearing box are equipped with positioning pin seat. When the bearing box needs to be fixed in the correct position, use positioning pins for installation. For the position of the pin hole for positioning the bearing housing and the diameter of the pin, please refer to the attached table 6 at the end of the volume.