| 摘要 |
PURPOSE:To prevent the switching under a high load by communicating an oil path to a selector valve from between a solenoid valve and the port of a line pressure control valve and providing an orifice on the inlet side oil path of the solenoid valve. CONSTITUTION:The line pressure is guided to one side or the other side of a hydraulic actuator 65 via a selector valve 70, and a two-wheel/four-wheel drive switching engagement clutch 55 is released or coupled by this actuator 65 to perform a switching action. The line pressure is guided to the port 91f of a line pressure control valve 90 by a solenoid valve 97 to perform low- pressure control under a low or medium load. Under this condition, the oil pressure of the port 91f can be guided to the actuator 65 for switching, thus the switching under a high load is restricted. At the time of such switching, the line pressure feed is restricted by an orifice 89, and the oil pressure at the port 91f is used for the actuator 65 and reduced. The line pressure is temporarily increased by the line pressure control valve 9p, and a belt slip is surely prevented. |
