Torque transmission device

This claims the benefit of German Patent Application No. 10 2005 059 408.5, filed Dec. 13, 2005 and hereby incorporated by reference herein.

The present invention relates to a torque transmission device having a torque converter which is accommodated in the drivetrain of a motor vehicle, for transmitting torque between a drive unit and a transmission, and which has a converter housing that is rotationally mounted about an axis of rotation and is nonrotatably connected to the drive unit.

An object of the present invention is to devise a torque transmission device, which will be optimized with respect to space requirements, have a simple design, and be cost-effective to manufacture.

The present invention provides a torque transmission device having a torque converter which is accommodated in the drivetrain of a motor vehicle, for transmitting torque between a drive unit and a transmission, and which has a converter housing that is rotationally mounted about an axis of rotation and is nonrotatably connected to the drive unit, that the torsionally fixed connection between the drive unit and the converter housing includes a tubular connecting element that is disposed coaxially to the axis of rotation of the converter housing. The configuration of the connecting element creates a clearance space radially outside of the same in the axial direction between the drive unit and the converter housing, permitting a drive shaft, projecting from a differential gear, for example, to pass through perpendicularly to the axis of rotation of the torque converter.

One preferred exemplary embodiment of the torque transmission device provides for a fastening flange, which is attached to the converter housing, to extend from the end of the connecting element facing the converter housing. The fastening flange is preferably welded to the converter housing.

Another preferred exemplary embodiment of the torque transmission device provides for the fastening flange to project radially outwardly from the end of the connecting element facing the converter housing. This facilitates welding of the fastening flange to the converter housing.

Another preferred exemplary embodiment of the torque transmission device provides for the fastening flange to have a plurality of centering tabs which engage in centering recesses provided in the converter housing. This permits centering of the connecting element in relation to the converter housing in a simple manner.

Yet another preferred exemplary embodiment of the torque transmission device provides for the end of the connecting element facing away from the converter housing to be terminated by an end wall. The end wall enhances the stiffness of the connecting element.

Another preferred exemplary embodiment of the torque transmission device provides for the end wall to be integrally formed in one piece with the connecting element. This reduces the number of structural components requiring assembly or connection.

Another preferred exemplary embodiment of the torque transmission device provides for the end wall to have the shape of a circular disk having a bent-over peripheral region. The bent-over peripheral region is used for integrally joining, in particular welding, the end wall to the connecting element at any given axial positions.

Another preferred exemplary embodiment of the torque transmission device provides for the end wall to have a centering element. The centering element preferably projects from the end wall into an opening that is provided in an output shaft leading out from the drive unit.

Another preferred exemplary embodiment of the torque transmission device provides for a torque converter drive plate to be fastened to the end of the connecting element facing away from the converter housing. The torque converter drive plate is preferably secured on the drive side to a so-called flexplate, which is fastened, in turn, to an output shaft projecting from the drive unit.

Another preferred exemplary embodiment of the torque transmission device provides for the torque converter drive plate to have a tubular fastening portion from which a driving flange projects radially outwardly.

The tubular fastening portion of the torque converter drive plate is integrally joined, in particular welded, to the connecting element.

Another preferred exemplary embodiment of the torque transmission device provides for the torque converter drive plate and the connecting element to be integrally joined together to form one piece. This reduces the number of structural components requiring assembly or connection.

Other preferred exemplary embodiments of the torque transmission device provide for the connecting element to be a formed part, in particular a rollformed part. The connecting element is preferably integrally formed in one piece with the fastening flange, the end wall, and/or the torque converter drive plate.

Other advantages and features of the present invention and details pertaining thereto are derived from the following description in which various exemplary embodiments are explained in detail with reference to the drawings. In the accompanying drawings, the figures show:

FIG. 1 shows a torque transmission device in accordance with a first exemplary embodiment, in half section.

FIG. 2 shows a torque transmission device in accordance with a second exemplary embodiment, in half section.

FIG. 3 shows a torque transmission device in accordance with a third exemplary embodiment, in half section.

A portion of a drivetrain 1 of a motor vehicle is illustrated in FIG. 1 . Accommodated between a drive unit 3 , for example an internal combustion engine, a crankshaft 4 leading out therefrom, and a transmission 5 , is a hydrodynamic torque converter 6 . Crankshaft 4 of internal combustion engine 3 is fixedly connected via bolted connections 7 to a driving disk 8 which essentially has the shape of a radially extending annular disk. Driving disk 8 is referred to as a flexplate. A flywheel ring gear 9 is provided radially externally to driving disk 8 .

A fastening flange 11 of a torque converter drive plate 12 is secured by bolted connections 10 to the radially outer peripheral region of driving disk 8 . Radially inwardly, torque converter drive plate 12 has a tubular fastening portion 14 . Tubular fastening portion 14 is slid onto a tubular connecting portion 15 of a connecting element 16 . Connecting element 16 has the shape of a circular cylindrical surface, which is terminated at its drive-side end by an end wall 18 . End wall 18 is integrally formed in one piece with tubular connecting portion 15 . On the drive side, a mushroom-shaped centering element 20 is fastened to end wall 18 . Mushroom-shaped centering element 20 projects into a blind hole recessed in crankshaft 4 .

Fastening portion 14 of torque converter drive plate 12 is secured by weld seams 21 , 22 to connecting element 16 . A fastening flange 24 , which projects radially outwardly, extends from the end of tubular connecting portion 15 of connecting element 16 facing transmission 5 . Fastening flange 24 is secured radially outwardly by a weld seam 25 to a housing 28 of torque converter 6 . Radially inwardly of weld seam 25 , fastening flange 24 has a plurality of centering tabs 26 , which engage in corresponding recesses of housing 28 of torque converter 6 . Housing 28 of torque converter 6 is rotatable about an axis of rotation 27 and is equipped with a drive-proximal housing wall 30 and a drive-distal housing wall 31 . Fastening flange 24 of connecting element 16 is secured to drive-proximal housing wall 30 . Drive-distal housing wall 31 is combined with an impeller 32 of hydrodynamic torque converter 6 to form one subassembly.

Interposed between impeller 32 and drive-proximal housing wall 30 is a turbine 34 which is secured radially inwardly to a turbine hub 35 . Turbine hub 35 is connected nonrotatably to an input shaft 36 of transmission 5 . Located between turbine 34 and impeller 32 is a stator 38 which is supported by a freewheel 39 on an impeller hub 40 that is mounted, for example, by way of a toothing on a housing-mounted tubular piece 42 . Interposed in a generally known manner between turbine 34 and drive-proximal housing wall 30 is a converter lockup clutch 44 having a torsional-vibration damper 46 .

Connecting element 16 allows a drive shaft 48 , which projects from a differential gear, to pass through perpendicularly to axis of rotation 27 between driving disk 8 and housing 28 of torque converter 6 . By compensating for the requisite height differential, tubular connecting portion 15 of connecting element 16 makes it possible for converter 6 to be connected. Connecting element 16 may be designed as a shaped sheet metal part and manufactured in a forming process.

Exemplary embodiments similar to those in FIG. 2 through 3 are shown in FIG. 1 . The same reference numerals are used to identify equivalent parts. To avoid repetitive explanations, reference is made to the preceding description of FIG. 1 . In the following, only the differences between the individual exemplary embodiments are discussed in detail.

In the exemplary embodiment shown in FIG. 2 , a torque converter drive plate 52 , which has a fastening flange 51 , is integrally formed in one piece with a tubular connecting portion 55 of a connecting element 56 . Drive-side end of tubular connecting portion 55 is terminated by a circular disk-shaped end wall 58 which has a bent-over peripheral region 59 . Bent-over peripheral region 59 of end wall 58 is configured on the inside of tubular connecting portion 55 . Fastened to end wall 58 is a mushroom-shaped centering element 60 which extends into a recess of crankshaft 4 . End wall 58 is secured radially outwardly by a weld seam 61 to connecting element 56 . The transmission-side end of tubular connecting portion 55 of connecting element 56 is butt-welded by a weld seam 65 to drive-proximal housing wall 30 of housing 28 of torque converter 6 . The exemplary embodiment shown in FIG. 2 has the advantage that, viewed in the axial direction, end wall 58 is attachable at different locations radially inside of tubular connecting portion 55 . Accordingly, this exemplary embodiment may be adapted to different installation situations, without entailing substantial outlay.

In the exemplary embodiment shown in FIG. 3 , a torque converter drive plate 72 , which has a fastening flange 71 , is integrally formed in one piece both with a tubular connecting portion 75 of a connecting element 76 , as well as with a drive-side, disk-shaped end wall 78 . As a result, the benefit is derived that connecting element 76 may be manufactured together with tubular connection portion 75 , end wall 78 , and torque converter drive plate 72 , as well as with fastening flange 71 using forming processes, in particular rollforming processes. Sheet metal may be used as feedstock for the forming processes, in particular rollforming processes. Fastened to end wall 78 is a mushroom-shaped centering element 80 which extends into a recess of crankshaft 4 . The transmission-side end of tubular connecting portion 75 of connecting element 76 is butt-welded by a weld seam 85 to drive-proximal housing wall 30 of housing 28 of torque converter 6 .

The term tubular can include perfectly tubular and substantially tubular.

1 . drivetrain

3 . drive unit

4 . crankshaft

5 . transmission

6 . torque converter

7 . bolted connection

8 . driving disk

9 . flywheel ring gear

10 . bolted connection

11 . fastening flange

12 . torque converter drive plate

14 . fastening portion

15 . connecting portion

16 . connecting element

18 . end wall

20 . centering element

21 . weld seam

22 . weld seam

24 . fastening flange

25 . weld seam

26 . centering tab

27 . axis of rotation

28 . housing

30 . housing wall

31 . housing wall

32 . impeller

34 . turbine

35 . turbine hub

36 . input shaft

38 . stator

39 . freewheel

40 . impeller hub

42 . tubular piece

44 . converter lockup clutch

46 . torsional-vibration damper

48 . drive shaft

51 . fastening flange

52 . torque converter drive plate

55 . connecting portion

56 . connecting element

58 . end wall

59 . peripheral region

60 . centering element

61 . weld seam

65 . weld seam

71 . fastening flange

72 . torque converter drive plate

75 . connecting portion

76 . connecting element

78 . end wall

80 . centering element

85 . weld seam