Computer Aided Design of Internal Involute Spur Gears

Abstract The modern theory of gearing provides principles of generation for conjugate gear tooth surfaces while computer aided design is a very powerful tool in designing a gear train with conjugate shaped tooth surfaces. It is possible to set up a mathematical model for internal involute spur gears if the theory of gearing and the concept of differential geometry together with computer aided design technique have been applied. The derived mathematical model of internal involute spur gears can be used for computer simulation of conditions of meshing, tooth contact analysis, stress analysis, dynamic analysis, lubricating analysis, and wearing analysis of the gear train. This paper covered the solutions to the following problems : (a) method of generation for internal spur gears with conjugate tooth surfaces; (b) derivation of equations for gear tooth surfaces and their surface unit normals; and (c) computer graphics of generated internal involute spur gears.