| 摘要 |
PURPOSE: To solve drag trouble of a running motor vehicle by providing an electromagnetic transmission gear retention control valve to a control pressure line and switching the valve from the gear release position to the gear retention position when a fault signal arises in the output terminal of the electronic control device. CONSTITUTION: A gear change element 7 to actuate a transmission gear frictional brake 5 of a planet gear transmission is connected to a gear change valve 10, which is actuated by an adjustment element 10a connected to a control pressure line 17. A control valve 13 is connected to the control pressure line 17, which controls communication between a main pressure line 33 and a return line 34. In such a selector device, an electromagnetic gear retention control valve 20 connected to an actuation pressure line 9 is arranged. In case when a fault signal arises at the output terminal of the control device, the control valve 20 switches from the gear release position 24, where the control pressure line 17 is released and the actuation pressure line 9 is shut off, to the gear retention position 25, where the condition of the lines 17 and 9 is reversed. |
