초록

A lock-up control valve is operated into a position to effect a lock-up condition of a torque converter by a governor pressure fed by way of a shift valve when the vehicle operates at high speeds in high gear.

대표청구항 ▼

A hydraulic control system for a vehicular automatic transmission including fluid operable units and a torque converter with a lock-up clutch, comprising: a source of first pressurized fluid adapted to be used for operating the fluid operable units; a source of second pressurized fluid that is indic

A hydraulic control system for a vehicular automatic transmission including fluid operable units and a torque converter with a lock-up clutch, comprising: a source of first pressurized fluid adapted to be used for operating the fluid operable units; a source of second pressurized fluid that is indicative of the vehicle speed; a lock-up control valve communicating with the torque converter and including a single control chamber and a valve member exclusively movable in response to pressure within said control chamber, said valve member being movable between a lock-up position in which the lock-up clutch is engaged and a release position in which the lock-up clutch is disengaged; and a shift valve communicating with said source of first pressurized fluid and with at least one of the fluid operable units, said shift valve including a chamber having a first port communicating with said source of second pressurized fluid, a second port communicating with said control chamber of said lock-up control valve and a port for drainage, said shift valve including a valve member movable between a low speed position in which said second port communicates only with said port for drainage and a high speed position in which said second port communicates only with said first port.