| 摘要 |
PURPOSE:To reduce the extent of a shift shock by installing such a back pressure selector valve as capable of switching between both m-speed and n-speed positions in linkage with a shift valve, and making it so as to drain a back pressure chamber of an accumulator at the side where hydraulic pressure is discharged at time of speed shifting. CONSTITUTION:This shift valve 10 using a back pressure selector valve in combination is provided with a spool 12 being selected according to the extent of hydraulic pressure in a port 16 where hydraulic pressure out of a shift solenoid 18 acts on, and at an m speed position of this spool 12, each interval between hydraulic pressures 20 and 22 as well as between 24 and 26 is interconnected to each other, and two oil passages 28, 30 are made into a state of being drained. In addition, at an n speed, the oil passages 22, 26 are drained, and both intervals between the oil passages 28 and 20 as well as between 30 and 24 are interconnected as well. In this connection, line pressure is fed to the oil passage 20, and hydraulic pressure out of a back pressure control valve 32 is fed to the oil passage 24. In addition, the oil passages 22, 28 are connected to each of both first and second oil chambers 34, 36 of first and second frictional clamping elements, while the oil passages 26, 30 are interconnected to each of back pressure chambers 40, 50 of both first and second actuators 38, 40. |
