Abstract: A variable transmission comprises a main shift part and a shift mechanism. The main shift part comprises at least an inner gear ring (B) with variable tooth-number which is connected with the shift mechanism. Said inner gear ring (B) is composed of a number of teeth and a pair of tapered discs (7,8) which are coaxially with said gear ring and the teeth are inter-connected to form a curled rack (3). The two side surfaces of the inner gear ring (B) are closely contacted with the facing walls of the two tapered discs (7,8), therefore the inner gear ring (B) is maintained as a circular ring. The end of the rack (3) is connected to the shift mechanism, and the inner gear ring (B) is engaged with a main planetary gear train disposed coaxially. The transmission ratio of the main planetary gear train varies with the change of the tooth-number of the inner gear ring (B).

Abstract: A variable transmission comprises a main shift part and a shift mechanism. The main shift part comprises at least an inner gear ring (B) with variable tooth-number which is connected with the shift mechanism. Said inner gear ring (B) is composed of a number of teeth and a pair of tapered discs (7,8) which are coaxially with said gear ring and the teeth are inter-connected to form a curled rack (3). The two side surfaces of the inner gear ring (B) are closely contacted with the facing walls of the two tapered discs (7,8), therefore the inner gear ring (B) is maintained as a circular ring. The end of the rack (3) is connected to the shift mechanism, and the inner gear ring (B) is engaged with a main planetary gear train disposed coaxially. The transmission ratio of the main planetary gear train varies with the change of the tooth-number of the inner gear ring (B).