Small small-sized bearing curvature and the relative curvature

Two within a pair of principal plane of rotors with different radius of curvature in no load cases in point contact with each other, this is called the point contact condition, as shown in figure 2. 7. In figure 2. 7, the above objects down to 1, the object plane below 1 notes for Ⅱ miniature bearing body, principal plane are expressed in 1 and 2, respectively. So, body 1 in planar 2 within the radius of curvature can be written as r1. Because 2 curvature radius r is flat, the curvature can be defined as p - ( 2. 24) Object 1 although the radius of curvature is always positive, but the curvature may be positive, negative, can also be used for regulation of the convex surface is positive, negative concave surface. 1 in order to describe the two corresponding plane rotary surface contact between the two states, want to use the following item (1) the definition of the object Curvature and: flat to the 2 p ( 2. 25) 2) Curvature difference:) = P1 - p12) + ( Pn - Pn F( p) 2. 26) Figure 2. 7 the geometric relationships between a contact body type ( 225). Type ( 2. 26) , using the convex and concave surface curvature sign convention. In addition must make F ( p) Take positive definition of curvature and curvature difference is the purpose of the contact of two objects can be as an equivalent spheroid and half plane of contact analysis. Using this concept, the front of curvature sign agreement becomes more apparent. The surface of the concave will make contact with more close to the body, this is equivalent to increase or equivalent radius of curvature. On the contrary, the surface of the convex equivalent to reduce or increase the equivalent radius of curvature. Because is an ellipsoid, curvature difference is only with the difference between the two orthogonal plane equivalent radius. If the two equal radius ( A sphere) , the curvature difference is zero. If the curvature differential to infinity, then the equivalent ellipsoid approximation for the cylinder. An example is used to determine whether the ball under the contact with the inner raceway of F ( ) Value ( As shown in figure 2. 8) :