国际象棋棋子木 www.cjonla.com.cn Basis for selection
According to the rotation of the loads acting on the bearings relative to the ring, the load bearing ring imported bear has three kinds: local load, cyclic load, load swing. Usually cyclic load (rotating load), swing load with tight fit; local load in addition to the use of special requirements, generally should not be used with tight fit. When the import bearing ring to bear dynamic load and heavy load, the inner ring and the outer ring should be used by interference fit, but sometimes the outer ring can be a little looser, should be able to swim in the axial hole bearing seat; when the import bearing bear load and load swing is light, with the ratio of tight fit slightly loose some.
(2) load size
Depends on the amount of interference between import bearing ring and the shaft or housing bore on the size of the load, the load is heavy, the larger the amount of interference fit; the load is light, using a small surplus with the amount. General radial load P less than 0. 07C for light load, P greater than 0. 07C is equal to or less than 0. 15C for normal load, P greater than 0. 15C for the heavy load (C for the bearing rated dynamic load).
Imported bearings in operation, the ferrule temperature is often higher than the adjacent parts of the temperature, therefore, imports of bearing inner ring may be due to thermal expansion and shaft loosening, the outer ring may be due to thermal expansion effect of bearings in the housing bore axially moving. Help select, on imported bearing device part temperature difference, swelling shrinkage should be taken into account, large temperature difference, and the inner ring of the shaft with the choice of the amount of interference should be bigger.
In order to eliminate the effect of elastic deformation and vibration, the clearance of the bearing should be avoided.
Structure and material of bearing shell hole
It is not appropriate to use the interference fit with the outer ring of the bearing shell, and the outer ring should not be rotated in the shell hole. For the installation of the hole in the thin shell, light metal shell hole or hollow shaft bearings, the use of thicker than the thickness of the shell hole, cast iron shell hole or solid shaft more tight fit.
Easy installation and removal
For heavy machinery, bearings should be used loosely. The tight fit, can choose the separation bearing, the inner ring and the cone with compact sets or unloading sleeve bearing.
Axial displacement of bearing
With a ring, when the requirements of bearing in operation can move in the axial direction, the bearing outer ring and bearing shell hole should adopt a loose fit.
Selection of fit
The combination of the bearing and the shaft is made of a base hole system, and the shaft is used in combination with the shell. The machine manufacturing industry with the bearing and the shaft of the tolerance system is different, the bearing diameter tolerance zone is the same with the following change, therefore, in the conditions with the bearing diameter and shaft fit more closely than usual. The diameter of the bearing shaft tolerance zone and the central axis of the tolerance zone, although the same is below the zero line, but its value is not the same with the general tolerance system.