Mazda Motor Corporation

Hidetoshi Kambara

Hiroshi Yoshimura

Toshihisa Marusue

Masahito Kitada

A control system controls a second to third gear shift of an automatic transmission in an advantageous way. The transmission has a 3-4 clutch, which is locked under hydraulic pressure, and a 2-3 brake provided with a lock pressure chamber and an unlock pressure chamber. The 2-3 brake is locked when a hydraulic pressure is developed in the lock pressure chamber only and is unlocked when a fluid pressure is developed in the unlock pressure chamber and when a hydraulic pressure is released from both the lock pressure chamber and the unlock pressure chamber. Hydraulic pressure is released from the lock pressure chamber so as to unlock the 2-4 brake only when a second to third gear shift is needed for the first time after engine ignition simultaneously with application of pressure to the 3-4 clutch so as to lock the 3-4 clutch. Other than when a second to third gear shift is needed for the first time after engine ignition, pressure is supplied into the unlock pressure chamber while keeping the lock pressure chamber supplied with pressure so as to unlock the 2-4 brake.

Growing community of inventors

Hiroshima, Japan

Hidetoshi Kambara