Ring function depending on its use, experienced professionals recommend that the rolling bearing and the corresponding bearing block secured to the shaft in the radial, axial and circumferential. Radial and circumferential positioning is usually achieved by friction, that is, the bearing race adopts a tight fit. Axially positioning often achieved by direct contact, for example: a nut, the bearing housing end cover, shaft stop collar, sleeve and collar etc.
Fitting of bearing mounting parts
Accordance with the predetermined shaft and a bearing housing tolerances prescribed ISO, while the outer diameter of the bearing tolerances and tolerances of the inner diameter of the bearing are by DIN 620. ISO tolerances are expressed in tolerance bands. Tolerance has two characteristics, its relative position to the zero line and its width. Tolerance positions are indicated by letters.
When selecting the bearing tolerances, pay attention to the following issues:
In order to take full advantage of the bearings and carrying capacity, it must be good to the bearing inner ring circumferential support.
Between the bearing sleeve and its fittings shall not have relative movement, otherwise it will damage the mating surfaces.
One of the inner and outer rings of the floating bearing and the shaft must be able to adapt to changes in the length of the housing, it means it can move axially. Only N and NU cylindrical roller bearings can move inside.
Try to make the installation and removal of the bearings as easy as possible.
In order to meet the first two requirements, the inner ring and outer ring of the radial bearing adopt a tight fit in principle. However, if the movable bearing must be moved axially or the non-detachable bearing must be able to be installed and disassembled, the two ferrules cannot be tightly fitted, and at least one ferrule is impossible. In this case, whether the bearing ring is subjected to local or cyclic loading is a determining factor. If the load does not change with respect to the direction of the ferrule, a clearance fit can be used, while another ferrule rotates with respect to the direction of the load, a tight fit is used in principle.
N and NU cylindrical roller bearings can achieve tight fit on both rings at the same time, because the length compensation can be made inside the bearing, and the inner and outer rings of the bearing can be installed separately.
Bearings under heavy loads, especially impact loads, require greater interference and tighter shape tolerances. Bearings that use a tight fit and the temperature between the inner and outer rings will reduce the radial clearance. Experts cautioned that this should be taken into account when selecting the radial clearance group.