| 摘要 |
PURPOSE:To prevent a valve body from being accidentally held at a permissible position so as to properly perform reverse stage prohibiting actions by delaying the supply of oil pressure to the hold port of a reverse stage prohibiting valve. CONSTITUTION:When a manual shift to reverse stage is actuated at the time of forward running, no oil pressure is applied to a hold port 118. Since vehicle speeds are equal to or more than a specified one, an electromagnetic drain valve 150 is opened so as to permit line oil pressure to be applied to an inhibit port 114 for positioning a valve body 102 and a plug 104 at prohibited positions while over-coming the force of a spring 120 so that the establishment of reverse stage is prohibited. And the supply of oil pressure is being kept on from ports 108 and 110 to the oil chamber 42a of No.3 clutch 42 and the inside oil chamber 48a and the outside oil chamber 48b of the second brake 48 until change-over to the prohibited positions is made. Accompanied with the above supply, oil pressure is applied to a hold port 116, but the upstand of the oil pressure is delayed by an orifice 166 as compared with that of the port 114. By this constitution, any erroneous operation will never take place which permits the valve body and the plug to be held at permissible positions at the time of reverse speed prohibition. |
