| 摘要 |
The vehicle transmission has a two-speed transmission and a multi- speed transmission coupled in tandem. A preselector device (30) determines the direction of movement of the shifting clutch of the two-speed transmission. Two solenoid valves (17, 19, 21; 18, 20, 22) control the pressure medium supply to the actuating cylinder of the shifting clutch. Circuit breakers, actuatable by the manual shift lever (3) of the multi-speed transmission and provided for locking the gear change of the two-speed transmission are inoperative in the non-rotational position of the pair of gears of the multi-speed transmission, that is in the neutral position of the manual shift lever (3) shown. The two-speed transmission can then be shifted. A centrifugal switch (40), driven at the speed of the input shaft (87) controls further circuit breakers (39, 39') and holds one in the closed state and the other in the open state respectively so that when the drive clutch is operated at high speed the two-speed transmission (87 to 91) is shifted to the stage with the larger transmission ratio and when operated at low speed to the stage with the smaller transmission ratio. This makes operation easier and reduces the synchronising work and the wear. <IMAGE>
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