| 摘要 |
PURPOSE:To readily reduce shock in speed change in the case that a direct- coupled clutch is operated in asociation with operation of at least two gear trains, by mechanically temporarily disengaging with the direct-coupled clutch upon speed changing. CONSTITUTION:When a vehicular speed is increased from a low speed condition where a direct-coupled clutch Cd is disengaged, and a medium speed stage clutch C2 receives hydraulic pressure from a hydraulic oil line 412 so as to establish a medium speed stage gear train, this hydraulic pressure is supplied through an oil line 412' to a timing valve Vt at the same time to move a piston 13 rightwardly and start to operate the direct-coupled clutch Cd. Then, hydraulic pressure in a hydraulic cylinder 14 is increased, and accordingly hydraulic pressure in a pilot hydraulic pressure chamber 92 of a reducing valve Vd is also increased. When this hydraulic pressure exceeds a fixed value, a valve body 90 moves rightwardly to cut off communication between an input port 93 and an output port 94, thereby preventing increase in excessive engagement force of the direct-coupled clutch Cd. Thus, it is possible to obtain weakly engaged area of the direct-coupled clutch Cd. |
