Abstract: From the precise shape of the tooth surface of the spiral bevel gears, the basic
components of the spherical involute tooth surface are discussed in detail. On the basis of
application of the theory about spherical involute for the spiral bevel gears, the characteristics and
shortcomings are analyzed and summarized, and a principle of forming spherical involute tooth
surface for the spiral bevel gears is proposed in the paper. Additionally, it makes inferences of its
key links namely the generating-line, working tooth profile, and the basic equations of the
spherical involute tooth surface, and proposes some approaches for its surface design and
manufacturing, in order to provide theory basis and ideas for the research on the spiral bevel
gears.

Key words: spiral bevel gears, spherical involute tooth surface, forming principle;
generating-line, working tooth profile