FAG super precision bearing installation process guide

The manufacturing process of FAG super precision bearings maintains an extremely high standard of clean environment, very strict inspection, and is protected by high quality packaging. In order not to affect the high performance of the bearing, care must be taken during installation. It is best to have a separate and clean installation room. Preparation of components Only approved components should be used for installation. Depending on the part, approval procedures include dimensional inspection, optical inspection or a pre-balancing process. The matching installation of components has a decisive influence on the function of the bearing. Therefore, it is sometimes necessary to match the bearing to the spindle or housing. For spindle bearings, bore and outside diameter tolerances are divided into groups, where the average tolerance for each group is marked on the package and on the bearing. Also the actual deviation of the bearing width is marked on the bearing (see page 19). Matching procedure In order to obtain the best performance or achieve accurate positioning of the spindle relative to the bearing seat, some special adjustments must be made, such as the end cover used for the axial clamping of the bearing outer ring in the bearing seat, and the bearing seat before tightening. There is a gap on the end face (as shown in Figure 2). For high-speed spindles, a spacer ring is recommended to compensate for the expansion of the ferrule caused by installation and preloading. Grease FAG super precision bearings do not need to be cleaned before adding grease. See Table 4 on page 179 for the amount of grease to be filled. Regreasing must be carried out in extremely clean conditions. The amount of grease to be filled is very demanding on both the filling and measuring equipment. Therefore, it is recommended to choose bearings that have been greased and sealed by Schaeffler. Mounting: When mounting the bearing on the shaft or housing, the rolling elements must not be loaded. Components with a tight fit (interference fit) are heated prior to installation. If the induction heating device in Figure 3 is used, the heating process is simple, fast and clean. Table 4 and Table 5 give the clamping force for locking the bearing inner ring with the lock nut. In order to avoid improper installation, the nut can be tightened by 3 times of the given torque, then loosened, and finally tightened with the given torque. Installation Instructions Installation Operation Test and Grease Distribution of Super Precision Bearings For grease lubricated bearings, a grease run-in operation must be performed before the spindle operation test. See appendix (page 230) for grease fill levels and guidelines for grease running-in procedures. Lock Nut Recommendations: A lock nut is often used to clamp the inner race of a spindle bearing to secure it to the shaft. A lock nut with an axial hole holds the bearing on the shaft better than a lock nut with radial grooves because it has minimal air turbulence at high speeds. The mounting surface of the lock nut must be ground on the same fixture as the thread. The axial runout value is recommended to be less than 2μm. The liner of the clamp is ground along with the threads and end face of the lock nut to prevent deflection during clamping. Spindle bearing installation To ensure quality, it is recommended to record the following measurements: Journal diameter, interference Spacer size difference Steady-state temperature Radial and axial runout values.