Configuration design of ten-speed automatic transmissions with twelve-link three-DOF Lepelletier gear mechanism

Many Lepelletier-type automatic transmissions are in production. Some of Lepelletier related configurations are still far from reaching maximum possible sequential speed ratios. This work focuses on analyzing and developing twelve-link three-DOF Lepelletier-type automatic transmissions to attain maximum speed ratios. Following the general trend of increased shift stages and a wider range of speed ratios, new ten-speed automatic transmissions are enumerated from the twelve-link three-DOF Lepelletier gear mechanisms. Furthermore, a ten-speed automatic transmission is modified from an existing eight-speed Lepelletier-type automatic transmission. The results show that the twelve-link three-DOF Lepelletier gear mechanism could reach eleven forward speeds at most. Nomographs are shown to be practical in detecting possible configurations and their clutching sequences.