| 摘要 |
PURPOSE:To reduce a total time of shift operation by providing a hydraulically operated first clutch and the second clutch capable of performing engaging and disengaging operation, and effecting shift operation by means of an actuator. CONSTITUTION:A hydraulically-operated first clutch 6 and the second clutch 19 capable of rapidly engaging and disengaging a clutch are located in series to a running transmission system. A a point of time A1, the second clutch 19 is rapidly disengaged in linkage with the starting of shift operation, and the working pressure of the first clutch 6 is reduced to a given low pressure P2. During a time between points of time A2 and A3, the second clutch 19 is rapidly engaged in linkage with completion of shift operation by means of actuators T1-T3, and the working pressure of the first clutch 6 is gradually increased. During the time between points of time A4 and A5, a load sensor 33 to detect the traction load of a working vehicle is provided. When a detecting traction load is high, operation to increase the working pressure of the first clutch 6 is rapidly performed. This constitution decreases a shift operation time. |
