Development of concave conical gear used for marine transmissions - (1st report, principle of generating helical concave conical gear)

Conical involute gears used for marine transmissions are mostly helical ones. These gears are available in the form of not only intersecting axis gears but also nonintersecting-nonparallel axis gears. The contact between tooth surfaces of a pair of gears is the point contact. Tooth surface durability is generally low. In order to overcome this weak point, one of the authors invented a-new type of conical gear called "Concave conical gear". Concave conical gear has higher tooth durability than the conventional conical involute gear. In this paper, a method to generate the helical Concave conical gear is newly developed. First, the principle of the generating method is introduced, and the tooth surface is analyzed theoretically. Second, test gears are ground. Tooth surfaces of the test gears are measured and compared with theoretical ones, and good agreement is observed.