The influence of the rolling bearing surface tangential stress

When determining the relationship between the contact deformation and load, for most applications, just consider vertical concentrated load on the surface of the effect on is enough. Moreover, in most applications, the rolling bearing lubrication is sufficient, at least between roller and raceway sliding can be ignored. This means that, compared to normal stress and ACTS on the rolling element and raceway contact area, which are round on the contact shear stress is negligible. But in determining the bearing surface of the rolling contact fatigue durability, surface shear stress can not be ignored, and in many cases it is to determine the durability of rolling bearings under given conditions of the most important factor. To determine the combined effect on the surface of z: normal stress and tangential stress ( Drag the power) To the subsurface stress influence, the way it is used, need to adopt numerical calculation. / willen and Schlicht based on several sets of the ratio of the surface shear stress and normal stress calculation て な surface stress field. / Dr. Wirgin and Schlicht 이 assume von Mises stress is the most important impact fatigue failure number 0 p - , and in figure 6. In the 18 shows that this kind of stress. = 0 619 is from 10 refs) , it table 6 = 025 as the surface shear stress and normal stress ratio increases, さ の stress in different depth. The figure also shows that = 0 = 0 = 0. 05 big von Mises stress is closer to the surface, when a/o = 0. 3, the maximum von Mises stress appears on the surface. Other researchers have also found that if the contact surface in addition to the method of 0. 5 to 1. 52. 02 to stress and shear stress, the maximum shear stress have the tendency of increase with the 2 b, its location is closer to the surface ( As shown in figure 6. 19 for different surface shear stress ( r/or) , the reference literature [ 11 - 151). 。 References [ 16 - 18] Material stress ( ow/o) The changes with the depth of the high-order surface effects on contact stress solution. The above reference documents not comprehensive, and just want to give this some representative works in the field of knowledge. Discussed above confined to normal load and uniform surface shear stress concentration under the joint action of surface stress field problems. Surface stress and normal stress ratio is also known as the coefficient of friction. Because rolling contact body surface micro yuan on a small back convex gravamen, so in practice, both neither can appear as shown in figure 6. 6 and figure 6. 7 said uniform normal stress field, also won't appear evenly cut stress field. Saves people such as 'the figure 6. 20 models of elastic alignment is proposed. Kalker established a mathematical model to calculate the concentration contact surface with arbitrary distribution of shear stress and normal stress produced by the surface stress distribution. Ahmad b people put forward such as subdivision method ( 补丁方法) Any concentration of, can be used to determine the contact surface by area = ab in arbitrary distribution of shear stress caused by surface stress. Load on the surface of a Hertz, for example, this method can be combined with the method of Thomas and Hoerwch, by superposition can determine the rolling element and raceway contact surface stress distribution of the time. Harris and Yu used this method to prove that, when the surface shear stress is added to the Hertz stress, the maximum orthogonal shearing stress range, namely 2 ro is not change. Figure 6. 21 illustrates this state. Lundberg - Palmen fatigue life theory of b) Is based on the maximum orthogonal shearing stress as cause early figure 6. 20 and the ideal elastic alignment model to predict fatigue life of rolling bearing the full extent of real roughness elastic ring test method. it is more suitable for certain wavelengths of delta fatigue failure stress, but the use of the theory of a) Using elastic Ming method. it parameters of Hea contact model for convenience, saying only a flexible figure in body, in fact if the acceptor is in doubt. Instead, for the same elastic modulus of materials, the deformation will be made by the two points