Method for shifting an automatic transmission

Abstract

A method for shifting an automatic transmission, including a drive region, a hydrodynamic converter, an output region, and exactly one planetary gear that acts in a first operating state and a second operating state. In order to shift to different gears of the automatic transmission, different transmission ratios are set in the strictly mechanical power branch by disengaging and engaging clutches and/or brakes in the drive region. The planetary gear set in the output region in the case of at least two different transmission ratios in the strictly mechanical power branch, the rotational movement transmitted by the strictly mechanical power branch is stepped up, in order to always set additional gears.

Claims

1. A method for shifting an automatic transmission, comprising: providing the automatic transmission with a drive region, a hydrodynamic converter, an output region, at least one of clutches and brakes in the drive region, and exactly one planetary gear set in the output region, the planetary gear set acts in a first operating state as a summation gearbox for simultaneous parallel drive power transmission via the hydrodynamic converter in a hydrodynamic power branch and around the hydrodynamic converter in a strictly mechanical power branch and in a second operating state to step up a rotational movement transmitted via the strictly mechanical power branch; setting different transmission ratios in the strictly mechanical power branch by disengaging and engaging at least one of the clutches and the brakes in the drive region in order to shift to different gears of the automatic transmission; and stepping up, by the planetary gear set, the rotational movement transmitted via the strictly mechanical power branch in at least two different transmission ratios in the strictly mechanical power branch for setting additional gears relative to the gears of the automatic transmission.

2. The method according to claim 1, wherein via the planetary gear set in the output region, in all the various transmission ratios in the strictly mechanical power branch, the rotational movement transmitted via the strictly mechanical power branch is always stepped up for setting of the additional gears.

3. The method according to claim 1, wherein the planetary gear set includes a sun wheel that is secured for setting of an additional gear.

4. The method according to claim 1, wherein the automatic transmission further includes a transmission output shaft, and the strictly mechanical power branch in the drive region includes four different transmission ratios that are set electively for setting of specifically four mechanical gears, wherein a power input of the planetary gear set is rotationally fixed with the transmission output shaft to avoid a ratio in the planetary gear set.

5. The method according to claim 1, wherein the automatic transmission further includes a transmission output shaft, and the step of setting the additional gears includes connecting a power output of the planetary gear set, in the form of a ring gear, with the transmission output shaft, in order to produce a ratio in the planetary gear set.

6. The method according to claim 5, further including a step of setting a gear with a power transfer via the hydrodynamic power branch and simultaneously via the strictly mechanical power branch, and a turbine wheel of the hydrodynamic converter is connected with a sun wheel of the planetary gear set, an output of the strictly mechanical power branch is connected with a planetary carrier of planetary gear set, and the transmission output shaft is connected with the planetary carrier of the planetary gear set, wherein the ring gear of the planetary gear set is fastened.

7. The method according to claim 1, wherein in the drive region various ratios of the strictly mechanical power branch are transmitted with interconnected planetary gearsets.

8. The method according to claim 1, wherein the automatic transmission further includes a transmission input shaft and a transmission output shaft, and gear ratios between the transmission input shaft and the transmission output shaft in all gears and intermediate gears are shifted relative to one another free of overlap.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 illustrates an automatic transmission, wherein the inventive method can be utilized;

(3) FIG. 2 illustrates a first gear of the automatic transmission;

(4) FIG. 3 illustrates a second gear of the automatic transmission;

(5) FIG. 4 illustrates the second gear with overdrive of the automatic transmission, in which the turbine brake is closed and the transmission output shaft is connected with the ring gear of the planetary gearset;

(6) FIG. 5 illustrates a third gear of the automatic transmission;

(7) FIG. 6 illustrates the third gear with overdrive;

(8) FIG. 7 illustrates a fourth gear of the automatic transmission;

(9) FIG. 8 illustrates the fourth gear with overdrive of the automatic transmission;

(10) FIG. 9 illustrates a reverse gear of the automatic transmission; and

(11) FIG. 10 illustrates a deviating design with an additional hydrodynamic retarder.

(12) Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

(13) FIG. 1 illustrates an automatic transmission featuring a drive region 1, a hydrodynamic converter 2 and an output region 3, wherein precisely one planetary gear set 4 is provided in output region 3. In drive region 1, that is originating from hydrodynamic converter 2 on the side of the transmission input shaft 5, various brakes 6 of multi-disk design are shown with which the individual components of the two interconnected planetary gear sets 8, 9 of drive region 1 can be optionally secured. Moreover, a so-called pump brake 7 is provided in order to secure the pump wheel of hydrodynamic converter 2. Thus, various ratios can be set in drive region 1 in order to create various gears in the transmission.

(14) The turbine wheel of hydrodynamic converter 2 can be secured by a turbine brake 10 which, in this case is also of multi-disk design. The brake at the same time also secures sun wheel 11 of planetary gear set 4 in output region 3.

(15) Planetary carrier 12 of planetary gear set 4 can be connected via jaw clutch 14 with transmission output shaft 13. Transmission output shaft 13 can moreover be connected by means of said jaw clutch 14 with ring gear 15 of planetary gear set 4.

(16) Ring gear 15 of planetary gear set 4 can be secured via brake 16, again with respect to the transmission housing.

(17) Planetary carrier 12 of planetary gear set 4 in drive region 3 can be secured by means of jaw clutch 17, also with respect to the transmission housing.

(18) The setting of the first gear of the automatic transmission is illustrated in FIG. 2, wherein the first gear is designed as combined hydrodynamic mechanical gear. Accordingly, planetary gear set 4 is used as summation gearbox in order to add together the drive power from hydraulic power branch 18 and the strictly mechanical power brand 19. Regarding the power flow, we refer to the process flow illustrated with the emphasized lines. A brake 6 in drive region 1 is shifted in order to connect the ring gear of planetary gear set 8 with transmission input shaft 5. Ring gear 15 of planetary gear set 4 in output region 3 is secured by means of brake 16 and planetary carrier 12 of planetary gear set 4 in output region 3 is connected via jaw clutch 14 with transmission output shaft 13.

(19) FIG. 3 illustrates the power flow in second gear, wherein in this case a strictly mechanical power transfer occurs exclusively via the strictly mechanical power branch 19. No speed-up ratio occurs in planetary gear set 4 in output region 3, or respectively no transmission ratio at all, so that the output of the strictly mechanical power branch 19 rotates with the same speed as transmission output shaft 13. For this purpose, planetary carrier 12 of planetary gear set in output region 3 is connected via clutch 14 to transmission output shaft 13. Pump brake 7 is closed, turbine brake 10 is open in contrast to FIG. 2, where both brakes 7, 10 must be open for the hydrodynamic power transfer.

(20) FIG. 4 shows that for shifting a second gear with overdrive, turbine brake 10 was also closed and transmission output shaft 13 was connected with ring gear 15 of planetary gearset 4 in output region 3in this case via jaw clutch 14. Strictly mechanical power branch 19 moves planetary carrier 12 so that a speed up ratio is produced in planetary gear set 4. Apart from that, the shifting position remains unchanged in accordance with the position in FIG. 3.

(21) Compared to the shifting positions in FIGS. 3 and 4 in drive region 1, another brake 6 is closed in FIG. 5, in order to set the third gear. Specifically, the planetary carrier of planetary gear set 8 in this case is connected with transmission input shaft 5. As a result, the third gear is set. Apart from that, the shifting position remains unchanged in accordance with the position in FIG. 3.

(22) In FIG. 6, the shifting position that is illustrated in FIG. 5 is now changed by changing the drive power flow via planetary gear set 4 in output region 3analog to the illustration in FIG. 4in order to set the third gear with overdrive.

(23) In FIG. 7 the fourth gear is set, in this case by closing third brake 6 in drive region 1, wherein the planetary carrier of planetary gear set 9 is connected with transmission input shaft 5. No ratio is set in planetary gear set 4 in output region 3.

(24) FIG. 8 shows again utilization of the overdrive in order to set an additional gearthe fourth gear with overdrive. Apart from that, the shifting position is consistent with that in FIG. 7.

(25) FIG. 9 illustrates setting of the reverse gear, wherein in this case the drive power is transferred exclusively via hydrodynamic power branch 18.

(26) Transmission input shaft 5 and transmission output shaft 13 rotate opposite to one another. In principle, rotation in opposite directions could also be provided in forward gears, and rotation in the same directions in reverse gears, depending on specific installation of the transmission in the remaining power train.

(27) In the arrangement according to FIG. 10 a hydrodynamic retarder 20 is additionally positioned on transmission output shaft 13. In particular, the rotor of hydrodynamic retarder 20 is supported directly by transmission output shaft 13.

(28) While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.