| 摘要 |
PURPOSE:To eliminate speed change shock at the time of backward speed change by governing the back pressure applied to an accumulator in case of selecting a backward speed stage to be lower than that in the other speed stages. CONSTITUTION:When a manual valve 3 is set on a backward stage, hydraulic fluid is supplied to C2 clutch 13, and simultaneously applied to a signal port 30 of an accumulator pressure governor valve 20. In that case, as the face area A3 of the third land 28 of a spool 21 is a little narrower than the area A4 of the fourth land 29, force for pushing up the spool 21 is decreased and low oil pressure is generated at an outlet port 23 to be applied as back pressure to an accumulator 18. That is, as it is ordinary to set a backward stage in a low-throttle opening, the accumulator back pressure becomes lower as load applied to C2 clutch 13 becomes smaller. Accordingly, speed change shock at the time of speed change to a backward stage can be eliminated. |
