| 摘要 |
PURPOSE: To provide the electro-hydraulic interlock system for a transmission with a simple structure for maintaining the transmission to a selected speed ratio, even when an electric obstacle is generated in the system. CONSTITUTION: Each electro-hydraulic interlock system 50 contains a pilot operated value for controlling one of a hydraulically actuated clutch 46 in response to the receipt of a pilot signal from an electro-hydraulic proportional valve proportionally controlled to a first electrical control signal. Further, a solenoid operated valve is also provided to selectively communicate the pressurized fluid from the one hydraulically actuated clutch to a pressure responsive section of the electrode-hydraulic proportional valve and in the event of an electrical failure in the system, the pressurized fluid from the one hydraulically actuated clutch 46 acts on the pressure responsive section and holds the electro- hydraulic proportional valve in the fluid passing condition. Thereby, the pilot operated valve is held in a position to maintain the hydraulically actuated clutch engaged. |
