| 摘要 |
In an automatic transmission for vehicles which has a fluid torque converter, a lock-up clutch for directly connecting the input and output members of the torque converter when pressure is supplied to its pressure chamber, and a gear transmission mechanism which has several hydraulic fluid actuated friction engaging devices for providing several speed stages: a control system which provides selective supply of pressures for actuating the friction engaging devices, which includes a system for manually selecting any of several desired shift ranges, several shift valves for selectively providing actuating pressures for the friction engaging devices according to the shift range selected by the manual selecting system and according to the balance between the opening of the intake throttle valve of the engine of the vehicle and its road speed, and a system for supplying pressure to the pressure chamber of the torque converter, when any one of several shift ranges is selected by the manual selecting device, only when the highest speed stage available from the gear transmission mechanism, for that shift range, is being provided. |
