| 摘要 |
A control device for a hydraulic direct-coupling clutch of a hydraulic torque converter installed in an automotive vehicle, which is adapted to control the supply of operating fluid to the direct-coupling clutch by means of an electrically actuatable selector valve. Pilot fluid pressure generated by a pilot fluid pressure source acts upon one end face of a valve body of the selector valve to bias the valve body to a position for supplying the operating fluid to the direct-coupling clutch. A drain line communicates a pressure chamber of the selector valve defined by the one end face of the valve body with a zone under a low pressure, and an electromagnetic valve is arranged across the drain line, which is adapted to open the drain line when energized, to permit the pilot fluid pressure in the pressure chamber to escape to the zone under a lower pressure. An electrical circuit supplies the electromagnetic valve with electric power at least dependent upon the speed of the automotive vehicle, for energizing the valve. Signal pressure generating means generates signal fluid pressure dependent upon the speed of the automotive vehicle. Fluid pressure regulating means regulates the magnitude of pressure of the operating fluid in response to the signal fluid pressure generated by the signal pressure generating means. Preferably, when the vehicle speed is lower than a predetermined value, the fluid pressure regulating means regulates the operating fluid pressure to values smaller than a value at which the direct-coupling clutch is rendered inoperative, whereby the direct-coupling clutch is rendered inoperative irrespective of the operative state of the electromagnetic valve. |
