Rolling bearing contact type

Under the condition of zero load, the contact is basically can be defined as the following two types of hypothetical 1) Point contact, the two surfaces in a point contact. 2) Line contact, the two surfaces along a straight line or curve contact width is zero. Obviously, when the load is in contact with body, will expand to become an elliptical. Equal principle problem for the length of the contact line contact, the line will be extended into a rectangle. Figure 6. 23 shows that in both cases the surface pressure distribution. Q Z 2 b catch round 2 b 2 Z X 2 b contact rectangular b) a) The point contact b) Ideal as a finite length line contact roller contact with length is larger in a way, along the roller axial distribution of stress and the stress of the figure shown in 62 is different. Because in a way at the end of roller lateral dent and make the material in the tensile state, child end compressive stress will be higher than the center of the contact stress. Figure 6. 24 shows the edge loading status. In order to offset the state, roller ( Or in a way) Can be made as shown in figure 1. 38 took the shape of the crown. That match the effect of load stress distribution becomes more uniform, but if the load was significantly increased, the edge will happen again ( As shown in figure 6. 25) 。 Palmen and lundberg of roller and raceway contact proposed a modified line contact condition, namely when exposed to round semi-major axis ( 2a) Roller effective length is greater than 1 and less than 1. 51, belong to the fixed line contact: if < 2 a, belong to the point contact; If 2 a> 1. 5, belongs to the attached edge loading line contact. This condition can be 6. 3 section introduces method of replacing type (with roller crown radius 2. 37) ~ ( 2. 40) The R to approximate to determine. See the case 6. 4 and 6. 5. In this section, the analysis of contact stress and deformation is based on existing elliptical contact area, is not included in the load under the action of a rectangular ideal roller contact area. In order to prevent edge loading and with high stress concentration, the roller bearing should follow.