According to the rotation of the load acting on the bearing relative to the ring, the bearing ring bears three kinds of loads: local load, cyclic load and swing load. Rolling Bearing Normal cyclic load (rotating load) and swing load adopt tight fit; unless there are special requirements for local load, tight fit is generally not suitable.
When the bearing ring bears the holding load and the load is heavy, the inner and outer rings shall adopt interference fit, but sometimes the outer ring can be slightly loose and can move axially in the bearing seat shell hole; Rolling Bearing when the bearing ring bears the swing load and the load is small When light, a slightly looser fit than a tight fit can be used.
The interference between the bearing ring and the shaft or shell hole depends on the load. When the load is heavy, a large interference fit is adopted; When the load is light, use a small interference fit. Rolling Bearing Generally, when the radial load p is less than 0.07c, it is a light load, and when p is greater than 0.07c, it is equal to or less than 0. It is normal load at 15C, and P is greater than 0. 15C is the heavy load (C is the rated dynamic load of the bearing).
When the bearing is running, the temperature of the ring is often higher than that of adjacent parts. Rolling Bearing Therefore, the inner ring of the bearing may loosen with the shaft due to thermal expansion, and the outer ring may affect the axial swimming of the bearing in the housing hole due to thermal expansion.
When selecting the fitting of the upper, the temperature difference and expansion and contraction of the bearing device shall be taken into account. When the temperature difference is large, Rolling Bearing the fitting interference between the shaft and the inner ring shall be larger.
When there are high rotation accuracy requirements for the bearing, in order to eliminate the influence of elastic deformation and vibration, Rolling Bearing clearance fit should be avoided. Structure and material of bearing housing hole
For the shell hole, Rolling Bearing the interference fit should not be used when matching with the bearing outer ring, nor should the outer ring rotate in the shell hole. For bearings installed on thin-wall shell holes, light metal shell holes or hollow shafts, a tighter fit than thick wall shell holes, cast iron shell holes or solid shafts shall be adopted.
For heavy machinery, loose fit should be adopted for bearings. When tight fitting is required, Rolling Bearing separate bearings, bearings with tapered holes in the inner ring and bearings with fixed or retracted sleeves can be selected.
During the matching, when one ring of the bearing is required to be able to move axially during operation, Rolling Bearing the outer ring of the bearing and the shell hole of the bearing seat shall be loosely matched.
The matching of bearing and shaft adopts the base hole system, while the matching with housing adopts the base shaft system. Rolling Bearing The fit of bearing and shaft is different from the tolerance fit system adopted in machine manufacturing industry. The tolerance zone of bearing inner diameter is mostly below change. Therefore, under the condition of the same fit, the fit ratio of bearing inner diameter and shaft is usually close.
Although the tolerance zone of the outer diameter of the bearing and the tolerance zone of the central shaft of the base shaft system are both below the zero line, its value is also different from the general tolerance system.