| 摘要 |
PURPOSE:To prevent overspeed of an engine by providing a hydraulic circuit in which a speed change ratio control valve and a regulator valve are connected to a selector valve through a manual valve so that a control hydraulic pressure is fed to the speed change ratio control valve and to the regulator valve from the selector valve when the manual valve is set at a specific position due to abnormal operation of a control valve. CONSTITUTION:A speed change ratio control valve 21 and a regulator valve 20 are connected a selector valve 26 by means of hydraulic circuits 61, 62, 64 through the intermediary of a manual valve 27. Further, when control valves 30 to 34 for controlling the selector valve 26 are closed and the manual valve 27 is set to a specific position due to occurrence of an abnormality, a control hydraulic pressure is fed to the speed change ratio control valve 21 and the regulator valve 20 from the selector valve 26 so that they are controlled toward the low speed stage and a predetermined line pressure is ensured. |
