| 摘要 |
PURPOSE:To realize a speed change in a low speed range and the backing engagement prohibition of an automatic transmission in high speed traveling by using the extremely simple circuit constitution and control with one transfer valve and one shift valve used. CONSTITUTION:Solenoid valves 66, 67, and 68 are opening/closing-controlled by a command from a control means 47, and the spool 63a of a 1-2 shift valve 63 is positioned on the right side when an automobile is high speed traveling, consequently reverse clutch pressure, led via a fourth output line 114, line 132, and ball valve 83, is not supplied to a low reverse brake line 130 to make the engagement of a low reverse brake 46 impossible. That is, the backing engagement of an automatic transmission is prohibitted when the automobile is traveling at a speed over a prescribed value even if a manual valve is R- range-operated. |
