| 摘要 |
To reduce the load on friction couplings 125, 127 when starting a vehicle in forward and reverse both couplings 125, 127 are engaged simultaneously so as to engage two gear stages G1 and G2. The gearbox has an input shaft 5, connected to an engine output shaft 6, and intermediate shafts, eg countershafts, 2, 3. The shaft 5 carries rotatably fixed driving pinions, eg 101, 110, engaged with rotatable gearwheels, eg 102, 103, on the shafts 2, 3 so as to form gear stages G1 to G5. The stages G1 to G5 are selectively connected or disconnected from their respective shafts by the couplings which are activated by actuating devices 130 to 132. For reversing, shafts 2, 3 carries switching sleeves 121, 122 that connects directly engaged reversing gears 113, 114 to their respective shafts. The sleeve 122 connects gear 114 to output pinion 111 engaged with spur gear 119 which transfers rotation to differential 135 and thereby to driveshafts 4. For forward drive output pinion 134 is engaged by sleeve 121 so as to transfer drive to spur gear 119. A free-wheeling device (318, fig 3) having a bridging coupling (323, fig 3) may be included on input shaft (1, fig 3) so that when starting in reverse the gear stage G1 does not become ineffective. The free-wheeling device (318, fig 3) opens in forward drive when there is no slip in coupling 125 of gear stage G1 and the driving power is passed on to gear stage G2 where there is still slip at coupling 127. <IMAGE> |
