| 摘要 |
PURPOSE:To enhance the controllability by providing a third control valve for shutting off a manual valve, a speed change limiting valve and a regulator valve when a control valve connected to a speed change ratio control valve and the regulator valve is normal, but for opening the speed change limiting valve when the control valve is abnormal. CONSTITUTION:When solenoid valves 8, 17 or an electronic control device are normal, a solenoid valve 18 is opened to feed a control pressure Pvc into a port 7c of a speed ratio limiting valve 7 so as to displace a spool 7p leftward in order to block ports 7a, 7b. Accordingly, a clutch supply pressure Pc fed to a regulator valve 15 and 2a speed change ratio control valve 16 is cut off. Accordingly, the speed change ratio control valve 16 carries out speed change ratio control with the use of a control pressure Pva from the solenoid valve 8. When the solenoid valve 8 or 17 is abnormal, the solenoid valve 18 is closed while the speed ratio limiting valve 7 is opened so as to feed a hydraulic pressure corresponding to the position of the manual valve 9 into the speed ratio control valve 16 and the regulator valve 15. |
