| 摘要 |
In a construction wherein an electronic pressure regulating valve (31 SIMILAR 36) is connected individually to each clutch of a two-stage transmission, i.e. main transmission (1st, 2nd, R, 4th, 3rd) and subtransmission (L, H) and each clutch can be controlled independently by a controller (10), the present invention cuts off the supply of an oil pressure to a transmission clutch for a present speed stage on the basis of a transmission instruction when the present speed stage is shifted down to the next stage at the time of power-ON, operates the pressure regulating valve so as to start the supply of the oil pressure to this transmission clutch at the point of time when the relative number of rotations at the transmission clutch for the next stage transmission becomes zero, then increases gradually the supply oil pressure after confirmation of the end of filling time to this transmission clutch, and thus prevents offensive feeling due to the speed change shock applied to an operator in whichever state the acceleration operation quantity and the brake operation state may be. In the shift-down operation involving the operations of the transmission clutches of both main and sub-clutches, a torque-OFF time is not provided to the sub-transmission clutch but the supply of the oil pressure to the clutch for the next stage transmission is started immediately so as to make the gradually increasing supply of the oil pressure. After this clutch is meshed, the gradually increasing supply of the oil pressure to the main transmission clutch is made after the filling time described above is over, and offensive feeling due to the transmission shock is prevented. |
