| 摘要 |
<p>PURPOSE:To soften shock due to coupling by constituting the action of a loose coupling valve to stand by during the period of time just before a clutch is coupled in after a speed ratio switching means has been switched over. CONSTITUTION:When a speed ratio switching valve 8 is switched, a control signal is output to an actuator in such a way that a reset valve 13 for a loose coupling valve is operated after a certain time (t1) has elapsed since the afore said switching. After that, with the control signal turned off after time (t2) has elapsed, the reset of the loose coupling valve 12 is released. When, for example, the valve 8 is switched over to first forward speed from second for ward speed, the aforesaid time (t1) is suitably determined after a time required for a clutch 1 on a coupling side, that is, on the side of first forward speed to be ready for coupling is taken into consideration, and the control signal is output in such a way that the valve 13 is actuated after the time (t1) has elapsed. This thereby permits the loose coupling valve 12 to be actuated while working oil pressure to be supplied to the clutch 1 side is decreased so that the valve is coupled in at low hydraulic pressure, thereby softening shock due to coupling.</p> |
