Bearing load is defined as the force that’s transferred from one bearing ring.
Usually when we check the bearing type, we often see Cr and Cor two options, what do these two groups of letters represent? Now tell you, Cr refers to the dynamic load rating of the bearing, Cor refers to the static load rating of the bearing. So what is the static load rating and dynamic load rating of a bearing? What is the relationship and difference between these two?
In the design of rolling bearings in often used in the three basic parameters are: to meet a certain fatigue life requirements of the basic dynamic load rating Cr (radial) or Ca (axial); to meet a certain static strength requirements of the basic static strength rating Cor (radial) or Coa (axial) and control the bearing wear limit speed No.
Rolling bearing basic rated static load (radial Cor, axial Coa) is the bearing maximum load rolling body and raceway contact centre caused by a certain contact stress when the equivalent of the imaginary radial load or centre axial static load. Rated static load is in the assumed load conditions decided, to the heart of the bearing, rated static load is the radial load, to the heart of the thrust bearing (angular contact ball bearing) is to make the bearing in half circle raceway by the load of the radial component, to the thrust bearing is the centre of the axial load. That is to say the bearing radial basic rated static load and axial basic rated static load refers to the bearing in static or rotating, the maximum can bear the load. Deep groove ball bearing at rest or slow rotation (speed n ≤ 10r/min) when the bearing capacity for rated static load.
Bearing rated dynamic load is: rolling bearing theoretically can withstand a constant radial load (constant axial load), in the role of the load the basic rated life of 100W turn, bearing the basic rated dynamic load reflects the rolling fatigue resistance of the bearing. The basic dynamic load rating of radial bearings and thrust bearings are called radial dynamic load rating and axial dynamic load rating, with Cr and Ca. Groove ball bearing in the rotation (speed n>10r/mim) when the bearing capacity for the basic dynamic load rating.
The rated dynamic load is the load that the bearing is subjected to at a rated life of 1 million revolutions. The rated static load refers to the bearing under the load, static when the load is the largest rolling body and collar raceway contact, rolling body and collar raceway of the permanent deformation of the sum of rolling body diameter of one million.
Bearing life and bearing load rating has a certain relationship, then what situation we through the bearing load rating to choose the bearing? The main points are as follows.
1, under the action of continuous or intermittent shock loads, the bearing is stationary.
2, in the role of the load, bearing only slow reciprocating oscillation or regulatory movement.
3, in the role of the load, bearing speed is very low (less than 10 revolutions per minute flat) and only a very short life. In particular, in this case, for a given equivalent load P, the life formula will give a very low required basic dynamic load rating C. Therefore, the selected bearing may be severely overloaded in actual operation.
4、In addition to the normal working load required, the bearing is also subjected to very heavy shock loads and the bearing is rotating.
The above various cases, the bearing can withstand the load does not depend on the fatigue of the material, but according to the load on the raceway caused by the degree of permanent deformation.