| 摘要 |
A method of shifting at least one of a speed increasing stage (H) and/or a speed reductions stage (L) in a claw shifted transfer gear box (VG) in a drive train of a vehicle having a drive engine and a load shiftable shift transmission (SG). The transfer gearbox (VG) is shifted into the neutral position (N) and, after the synchronization, is shifted into the speed increasing stage (H) or the speed reductions stage (L). During synchronization, the shift transmission (SG) is decelerated or accelerated, by activating at least an additional shift element, so that the output rotational speed (n_SG) of the shift transmission (SG) is matched to the output rotational speed (n_VG) of the transfer gearbox (VG), multiplied by the target gear ratio in the transfer gear box (VG). |
| 主权项 |
1. A method of shifting at least one of a speed increasing stage (H) and a speed reduction stage (L) in a claw shifted transfer gearbox (VG) in a drive train of a vehicle comprising a drive engine and a power shiftable shift transmission (SG), the transfer gearbox (VG) being shifted into a neutral position (N) and, after synchronization, either the speed increasing stage (H) or the speed decrease stage (L) is shifted in the transfer gearbox (VG), the shift transmission (SG), during synchronization, is either interconnected or accelerated by activating an additional shift element such that an output rotational speed (n_SG) of the shift transmission (SG) is equalized with an output rotational speed (n_VG) of the transfer gearbox (VG), multiplied by a target gear ratio in the transfer gearbox (i_VG), and during a traction upshift, the transfer gearbox (VG) is shifted from the speed reduction stage (L) into the neutral position (N), the method comprising the steps of:
thereafter activating a shift element of a lower gear of the shift transmission (SG) such that the output rotational speed (n_SG) of the shift transmission (SG) is reduced until the output rotational speed (n_SG) of the shift transmission and the output rotational speed (n_VG) of the transfer gearbox (VG) are synchronized, shifting the transfer gearbox (VG) from the neutral position (N) into the speed increasing stage (H), realizing the upshift without an engine deceleration intervention, and during a traction upshift in the drive train from a fifth gear into a sixth gear and after the neutral shifting of the transfer gearbox (VG), reducing an activating pressure (SE—2) of the shift element, which is assigned to the fifth gear, to a predetermined value, while increasing an activating pressure (SE—3) of the shift element which is assigned to the fourth gear. |
