Discussion on the relationship between the load property of stainless steel bearing and the fitting mode.
The load borne by stainless steel bearing can be divided into light load, conventional load and heavy load according to the load size, and static load, variable load and impact load according to the time change of load. In addition, according to the load direction, it can be divided into rotating load, static load or variable load.
Rotating load, static load or variable load are not the load properties of the bearing itself, but the load properties observed relative to each bearing ring. When determining the fit of the inner and outer rings, it is necessary to first see whether they are rotating loads or static loads, and then judge whether to use interference fit or clearance fit.
Rotating load refers to the continuous change of load direction with respect to the ferrule, which is independent of whether the ferrule itself is rotating or stationary. Static load means that the load direction is always toward the corresponding part of the ferrule, regardless of whether the ferrule itself is stationary or rotating.
In principle, the ferrule bearing rotating load shall adopt interference fit. If clearance fit is adopted, the ring will slip on the mating surface of the shaft or bearing seat; When the load is large, it will damage the mating surface or cause fretting wear. For the tightness of the fit, it should be considered that the interference can be guaranteed even under the conditions of bearing load, temperature difference between the inner race and the shaft or temperature difference between the outer race and the bearing seat during operation. According to different operating conditions, the inner ring of bearing mainly adopts k5, m5, n6, etc., and the outer ring mainly adopts N7, P7, etc.
As for large bearings, sometimes in order to avoid the difficulty of assembly and disassembly, the method of clearance fit of rings bearing rotating load is also adopted. In this case, the shaft shall be made of hard materials, with surface finish machining and sufficient lubrication to prevent damage caused by slipping to a large extent.
As there is no slipping condition between the ring bearing static load and the stainless steel bearing or bearing seat, clearance fit or transition fit is adopted. The degree shall be determined according to the accuracy required by the operating conditions and after the deformation of the ferrule, it will not cause excessive load distribution. Generally, the inner ring adopts g6, h6, js5, etc., and the outer ring adopts H7, JS7, etc.
For the variable direction load, it can not be the same, but the inner and outer rings are mostly fitted with interference.