Bearing load between the rolling element and raceway

In rolling bearing, acting on the load between roller and raceway can only form a very small contact area between them. So, despite the rolling element load may be moderate, but the stresses induced in the rolling element and raceway surface usually is high. In dynamic compressive stress on the surface of the more than 1380 mpa ( 200, 00 p0 continuous operation under the condition of bearing is not uncommon, in some applications, and durability experiment, rolling surface compressive stress even more than 3449 mpa ( 500，000i) O due to the fact that effective regional stress will increase rapidly with depth under the surface of roll, so on the surface of a high voltage stress will not spread to the whole rolling element. So, in the rolling bearing of rolling element in the design of the overall damage does not usually the main consideration, but rolling surface damage is the focus of attention. This chapter will consider only the stress generated by the deformation of the surface and near surface and the deformation produced by the contact stress. Because of rolling element stiffness characteristics, the deformation usually are small, such as the steel bearings generally less than 0. 025mm( 0. 001年) 。 Het in 1896 put forward about two elastomer in point contact local stress and deformation of the classical solution, this day, this stress is often referred to as Heta contact stress or Het stress for short. In order to establish math expression of the contact stress, must have a solid foundation of the principle of mechanics of elasticity. However the purpose of this section is not about the theory of elasticity, but only to introduce the subject of basic methods to illustrate the complexity of the problem of contact stress. DtytyzX role according to the Z5 + a stress state on infinitesimal cube purposes, consider figure 6. 1 composed of homogeneous isotropic materials infinitesimal in the stress state of the elasticity of the cube in no sense objects under the condition of gravity, according to the x direction stress on the static equilibrium conditions can be obtained: ro, dyd: +, dad: +. drdy - o, +'du lyda atOT+- dy dxd: - t+- Dr Dx dy = 0, y o, then. 或。 or=062) Ox oy or similarly, oo in y and x direction respectively. 或= 0 63) Oy ox az oo, or in the or = 0 64). Type ( 6. 2) - Type ( 6. 4) Is the equilibrium equation in the cartesian coordinate system.