In the installation of SKF bearings, the engineers are most concerned about how to operate correctly. Improper operation may cause damage to the SKF bearings. If it is operated at high speed and the working temperature is high, special attention should be paid to the fitting of the rotating ferrule not to be too loose to prevent eccentric vibration, and the fit of the fixed ferrule should not have gaps to prevent the ferrule from deforming under load. Excite vibration. The burning interference of the rotating ferrule should also be small within the possible range. As long as the influence of thermal expansion at the working temperature and the influence of centrifugal force at the maximum speed are ensured, the creeping or sliding of the tight-fitting surface will not be caused. According to the size of the working load and the size of the SKF bearing, the fixed ring selects a very small clearance fit or interference fit. Too loose or too tight is not conducive to maintaining the original precise shape. It is necessary to accurately calculate not only the interference fit of the rotating ferrule, but also the proper fit of the fixed ferrule. The roundness of the shaft and the seat hole and the verticality of the shoulder should be required according to the corresponding accuracy of the SKF bearing. The assembly accuracy of the cage is guaranteed by the special assembly mold, which can fully guarantee the assembly accuracy requirements of SKF bearings. The condition for adopting a small interference fit for the fixed ring is that both sides of the mating surface have high shape accuracy and small roughness, otherwise, it will make installation difficult and disassembly even more difficult. Swing load and indeterminate load should be treated the same as rotating load in terms of fit. Too loose fit will cause damage to the mating surface. For the ferrule and shaft or seat hole that rotate relative to the load direction, transition fit or interference fit should be selected. The size of the interference is based on the principle that when the SKF bearing works under load, the 'creep' phenomenon does not occur on the mating surface of the ring on the shaft or in the seat hole. When the load is very light, or the ferrule occasionally rotates at low speed under heavy load, transition fit can be selected. At this time, the shaft surface should have high hardness and small surface roughness. For heavy duty applications, the fit should generally be tighter than for light and normal duty applications. The heavier the load, the larger the interference should be. Spindles using paired double angular contact ball bearings are mostly loaded with light loads. If the fit interference is too large, the internal axial preload will be significantly larger, which will cause adverse effects. The main shaft of the double row short cylindrical roller bearing and the main shaft of the tapered roller bearing have a relatively large load, so the interference is relatively large. Sometimes the direction and magnitude of the load cannot be accurately determined. For example, in high-speed rotating machinery, in addition to the load with a fixed direction of the rotor weight, there is also a rotating load caused by an unbalanced mass. If this rotating load is higher than the fixed load. If the rotational load is much smaller than the fixed load, the resultant load is the swing load. Regardless of rotational or oscillating loads, SKF bearings are constantly changing in size and orientation. In the variable working state, some ferrules may be subjected to a rotating load, sometimes a fixed load, and sometimes a swing load. Such loads are called indefinite loads.