Toyota Jidosha Kabushiki Kaisha

Aisin Aw Co., Ltd.

Kaunori Ishikawa

Kazumasa Tsukamoto

Kunihiro Iwatsuki

Hideo Tomomatsu

Hiroji Taniguchi

Yuji Kashihara

Takuji Taniguchi

Tadashi Kondo

A primary regulator valve has a cutback port which regulates a line pressure to increase, at the first speed of D range, a throttle pressure is applied to the cutback port through a cutback valve. The primary regulator valve sets the line pressure from a line pressure port higher. The cutback valve has a spool which is compressed in one direction. A first control chamber which is connected to a hydraulic servo (for example, a second brake hydraulic servo) which hydraulic pressure is applied at more than the second speed is formed against the pressing direction, a second control chamber which is connected to a hydraulic servo (for example, a second-coast brake hydraulic servo) to limit a coasting condition of the second speed is so formed as to follow the above pressing direction. At the second speed of second range, the cutback valve, as the first speed of D range, the throttle pressure is applied to the cutback port. Furthermore, the primary regulator valve has a control chamber which regulates the line pressure to decrease. A pressure control valve (for example, a linear solenoid valve to control a lock-up clutch) is connected to the control chamber to reduce the line pressure when a manual valve is selected from N range to D or R range.

Hydraulic control device with cutback valve for an automatic transmission

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Toyota, Japan

Kaunori Ishikawa