Chap, 5.2 The fundamental law of gearing( 2. The involute tooth form Inⅴ olute function 发生线 渐开线 cos ak 0. = inva =tan -ak involute B 64 base circle2. The Involute Tooth Form involute base circle Involute function Chap.5.2 The fundamental law of gearing(6) k k k k k b k inv r r      = = − = tan cos