DE102011011118A1 - Rear axle mounted in rear wheel of motor vehicle such as passenger vehicle, has a space formed along longitudinal center axis of one of the longitudinal arms and cross beam and is set as free space - Google Patents

Abstract

The rear axle comprises two longitudinal arms (11) for coupling to vehicle body, and a cross bar (15) which connects the arms. The cross bar is tensioned between the ends (16) against the forward direction of travel of the motor vehicle. The space formed along the longitudinal center axis (C) of one of the longitudinal arms and the cross beam is set as a free space.

Description

The invention relates generally to the field of motor vehicles with alternative drives, and more particularly to a rear axle that accommodates the particular spatial requirements of such drives.

Motor vehicles are for the most part driven by internal combustion engines. In the present case, alternative drives are understood in particular to mean gas and electric drives, as well as hybrid drives which combine different types of drive.

Such alternative drives require large-volume energy storage such as batteries, fuel cells or gas tanks, which must be accommodated as crash-proof as possible in the vehicle in order to minimize the risk potential for the occupants in an accident.

As a suitable arrangement location for such energy storage is currently considered the space under the rear seats to the rear axle. This space should therefore be made as large as possible.

However, available rear axles, which are designed for motor vehicles with internal combustion engines, are for this purpose only partially suitable because they were constructed under other conditions. In such cases, the design is often based on an achievable boot volume or the placement of a spare tire.

Out DE 100 03 230 A1 is a rear axle for a motor vehicle is known, which comprises two trailing arms for coupling to a vehicle body, and a cross member which connects the trailing arm, wherein the cross member at its ends in each case has a cross-sectional profile which is penetrated by a rotational axis of a vehicle wheel. The wishbone is pulled in its central region in the direction of travel arrow-shaped forward. In addition, the rear axle is stiffened by another, front cross member between the trailing arms.

This is intended to create space for a spare wheel well in motor vehicles with low wheel overhang at the rear of the vehicle. For motor vehicles with alternative drives, as explained above, such a configuration, however, is not very suitable because it would reduce the crash-safe space for the required energy storage.

Another rear axle is off DE 10 2008 045 082 A1 known. In this, the cross member runs entirely behind the axes of rotation of the vehicle wheels, so that space for a rear-wheel drive is created. The cross member is connected via two-shell connecting elements, which at the same time each form a wheel, connected to two trailing arms. For vehicles with rear-wheel drive, this rear axle offers a simple construction combined with a low weight. In terms of non-driven rear axles, however, there is further savings potential.

The invention is based on the object to provide a non-driven rear axle for a motor vehicle, which allows a large space in the range from under the rear seats to the rear axle in particular for accommodating energy storage devices, drive units and the like.

This object is achieved by a rear axle according to claim 1. The rear axle according to the invention for a motor vehicle comprises two trailing arms for coupling to a vehicle body, and a cross member which connects the trailing arm, wherein the cross member at its ends in each case has a cross-sectional profile which is penetrated by a rotational axis of a vehicle wheel. It is characterized in that the cross member between its ends against a forward direction of travel of the motor vehicle is cranked, and formed by the trailing arms and the cross member space is formed at least in a band-shaped strip along the longitudinal central axis of the rear axle as a free space.

The rear axle according to the invention has a very small number of components with regard to its load-bearing structure, which makes manufacturing and assembly simple. For example, no additional connecting elements between the cross member and the longitudinal members must be incorporated. The vehicle wheels of the rear axle sit in front of the ends of the cross member. The shape of the rear axle makes it easy to adapt the rear axle to the respective requirements with regard to flexural rigidity and torsional rigidity.

The rear axle according to the invention can therefore be manufactured inexpensively. It is also characterized by a low component weight.

In particular, the rear axle according to the invention when used on a motor vehicle allows a large freedom of design for an optimized in terms of crash safety arrangement of energy storage, such as batteries, fuel cells, gas storage and the like, in the ground near the back seat to the cross member of the rear axle.

However, the rear axle according to the invention can also be used in motor vehicles with conventional drives, if in such from z. B. other reasons, a large ground level space requirement in the area between the rear bench and rear axle cross member should exist.

Advantageous embodiments of the invention are specified in further claims.

Preferably, the cross member extends between its ends with respect to the forward direction at least partially behind the axes of rotation of the vehicle wheels of the rear axle. As a result, an additional space gain is achieved.

According to an advantageous embodiment of the invention, the cross member is a one-piece hollow profile body with varying profile cross-section. By profiling, the above-mentioned adaptation in terms of bending stiffness and torsional rigidity can be achieved very easily in terms of manufacturing technology.

According to a further advantageous embodiment, a respective cranking section adjoins end sections of the cross member, which have the ends thereof. Between these Kröpfungsabschnitten a middle section is arranged. In this case, the cross member on a closed hollow profile, which is box-shaped in the range of Kröpfungsabschnitte, in the region of the central portion, however, is designed as a double-walled folded U or V-profile. As a result, a rigid, but torsionally soft structure is created, which is for ride comfort and driving safety advantage. On the other hand, sufficient stiffness for supporting spring and damper forces predominantly in the vertical direction of the vehicle as well as transverse forces is ensured in the region of the cranking sections and end sections.

In a further preferred embodiment, the cross-sectional profile of the cross member, starting from the central portion in the direction of the end portions in each case over a range in which the profile extension in the vehicle vertical direction is less than or equal to the profile extension in the vehicle longitudinal direction, in a range in which the profile extension in the vehicle vertical direction is greater as the profile extension in the vehicle longitudinal direction. This allows a particularly good support of vertical forces near the wheel.

According to a further advantageous embodiment, the U- or V-profile of the central portion is symmetrical with respect to a center line. It also has an opening angle in the range of 5 to 40 degrees. As a result, an advantageous Torsionsbeschgiebigkeit can be achieved in the middle of the cross member.

Furthermore, a corresponding suitable structure may be provided on the rear axle for supporting transverse forces against the vehicle body. This is preferably to be arranged such that the above-mentioned space is not affected. In an advantageous embodiment of the invention, a Panhard rod is provided for this purpose, which is coupled via a hinge to the cross member, wherein this joint is attached to one of the Kröpfungsabschnitte of the cross member. As a result, a particularly space-saving in terms of the required clearance lateral force support is achieved. By connecting the joint to the cross member, the structure of the rear axle remains simple.

According to a further advantageous embodiment of the invention, the longitudinal members are connected in the region of the Kröpfungsabschnitte and / or end portions of the cross member, resulting in a rigid composite.

For the same reasons, it is recommended that a damper mount on a side facing away from the forward travel direction of the cross member in the region of a Kröpfungsabschnitts and / or an end portion form or fasten.

The invention will be explained in more detail with reference to an embodiment shown in the drawing. The drawing shows in:

1 a schematic representation of a motor vehicle with an alternative energy storage,

2 a spatial view of an embodiment of a rear axle according to the invention in the direction opposite to the forward direction,

3 a representation of the rear axle 3 to illustrate the mounting position with respect to the vehicle rear wheels and a body-side support structure,

4 a partial view of the rear axle from diagonally behind,

5 a sectional view taken along the line VV in 4 .

6 a sectional view taken along the line VI-VI in 4 .

7 a sectional view taken along the line VII-VII in 4 .

8th a sectional view taken along the line VIII-VIII in 4 .

9 a sectional view taken along the line IX-IX in 4 .

10 a sectional view taken along the line XX in 4 .

11 a sectional view taken along the line XI-XI in 4 , and in

12 a partial view of the rear axle from behind.

1 shows a passenger vehicle 1 in which an energy store, for example a battery, a fuel cell, a gas tank or another fuel tank is close to the ground in an area 2 is housed, which extends from below the rear seat to a cross member of a rear axle of the vehicle. Instead of such an energy storage can also drive units or components thereof in the said area 2 be housed. In addition, the said range 2 be used for other purposes, such as storage space. To this area 2 as large as possible, the following is based on the 2 to 12 explained in more detail rear axle 10 for use.

As 2 shows includes the rear axle 10 initially two trailing arms 11 which extend substantially parallel to the direction indicated by an arrow V forward direction. The trailing arm 11 are each with a front end portion 12 over a rubber camp 13 hinged to a vehicle body, not shown, so that they can pivot about a substantially horizontal axis A. The trailing arm 11 are designed as sheet metal elements, which extend mainly in a vertical plane containing the longitudinal direction. As a result, the trailing arm 11 with respect to bending moments about a horizontal axis extending in the vehicle transverse direction a high bending stiffness. Optionally, the trailing arm 11 additionally stiffened by beads and the like. The trailing arm 11 continue to close with a rear end section 14 to a cross member 15 at. Instead of the single-shell sheet-metal trailing arm shown, depending on the load, double or multi-leaf trailing arms or trailing arms produced in other ways may also be used.

The crossbeam 15 runs essentially in the vehicle transverse direction. It is also arranged such that the cross-sectional profile of its ends 16 is penetrated in each case by a rotational axis B of a vehicle wheel HR of the rear axle, as in 3 easy to recognize. To accommodate a wheel bearing and attaching a vehicle brake is at the ends 16 or end faces of the cross member 15 in each case a preferably plate-shaped or disk-shaped trained wheel carrier 17 attached, for example, welded. However, it is also possible, corresponding fastening devices for a wheel bearing and / or a vehicle brake at the ends 16 of the crossbeam 15 Form or appropriate consoles on the circumference of the cross member 15 to install.

The crossbeam 15 is designed with regard to a simple production and assembly as single-storey hollow profile body. By varying in the vehicle transverse direction cross-sectional profile a rigid, but torsionally soft configuration is achieved. In particular, the cross member 15 be made of a hollow profile body, which initially has a closed, box-shaped cross-sectional profile. The latter is understood to mean both rectangular and polygonal, round or oval cross-sectional shapes in which the profile inner walls are spaced from each other. By appropriate profile deformation of the profile profile is explained in more detail cross member 15 get that the different requirements for a rear axle 10 optimally adapted.

As already stated, the cross member 15 arranged so that its ends 16 be penetrated by the rotational axes B of the rear wheels HR. Between his ends 16 is the crossbeam 15 but the forward direction of travel V opposite cranked. Towards the center of the vehicle is the cross member 15 towards the vehicle center thus offset in the vehicle longitudinal direction in the vehicle longitudinal direction with respect to the axes of rotation B of the rear wheels to the rear, which in view of the above range 2 to accommodate more space, for example, an energy storage is gained. This area 2 is not at least in the vehicle center by other components of the rear axle 10 impaired. Rather, one of the trailing arms 11 and the cross member 15 Spent space at least in a band-shaped strip along the longitudinal center axis C of the rear axle 10 to the cross member 15 designed as a free space.

In each case between a trailing arm 11 and the cross member 15 formed, pointing to the vehicle center angle is a spring plate 18 for supporting a vehicle spring 19 arranged. The spring plate 18 is presently designed as a sheet metal part and both on the trailing arm 11 as well as on the cross member 15 attached, preferably welded. As a result, the substantially rectangular connection between the cross member 15 and the respective trailing arm 11 stiffened.

Furthermore, between the rear axle 10 and the vehicle body not shown damper 20 incorporated, to support them the cross member 15 corresponding consoles 21 are attached. In particular 4 can be taken, are two such consoles 21 like a fork on the side facing away from the forward direction of travel V of the cross member 15 attached, for example, welded in the form of corresponding tabs. While the spring support takes place in front of the axes of rotation B of the vehicle wheels HR, the dampers engage 20 behind the axes of rotation B at the rear axle 10 at.

However, it is also possible, the spring support on the cross member 15 or with appropriate spring plate with respect to the forward direction of travel V behind the cross member 15 make.

Furthermore, the rear axle 10 a panhard bar 22 for supporting lateral forces against the vehicle body. The latter is in 2 by a body-side support 23 indicated. The panhard rod 22 extends in the vehicle transverse direction and is connected to a first end portion via a first joint 24 to the cross member 15 coupled, wherein the axis of rotation of the first joint 24 is substantially parallel to the longitudinal center axis C or forward direction V is. The coupling to the body-side support 23 takes place with the opposite end portion via a second joint 25 , The latter, according to the in 12 illustrated embodiment extending in vehicle vertical direction D axis of rotation. On the vehicle side, this is a fixed hinge pin 26 provided on which a socket 27 is rotatably mounted. The socket 27 or the radial direction thereof forms with the Panhardstab firmly connected to this 22 an angle β in the range of 1 ° to 15 °, preferably 2 ° to 10 °, to a compression of the rear axle 10 and to allow self-steering movements of the same.

Instead of the illustrated joint shape for the second joint 25 are also other designs possible, which allow a rotational movement parallel to the longitudinal center axis C or forward direction V and / or a rotational movement substantially in the vehicle vertical direction D.

Based on 4 to 11 should now the cross-sectional profile of the cross member 15 the above-explained rear axle 10 to be discribed.

As already stated, the ends are 16 of the crossbeam 15 arranged so that they include the axes of rotation B of the vehicle wheels HR. From these ends 16 go corresponding end sections 28 in the direction of the vehicle center each in a Kröpfungsabschnitt 29 over, with which an offset of the cross member 15 in the direction of the longitudinal center axis C of the rear axle 10 , ie is achieved against the forward direction of travel V. The two Kröpfungsabschnitte 29 are in turn about a substantially straight middle section 30 interconnected and integrally formed therewith.

In the area of the cranking sections 29 becomes the cross-sectional profile of the cross member 15 offset in relation to the axes of rotation B against the forward direction V to the rear. The trailing arm 11 as well as the consoles 21 for a damper 20 as well as the first joint 25 are preferably at the Kröpfungsabschnitten 29 However, if necessary, they can be arranged right down to the end sections 28 extend.

5 shows a section through the middle section 30 of the crossbeam 15 , In this area, the box-shaped hollow profile is formed into a double-walled folded U or V profile. This U- or V-profile is open at the bottom and has a lower torsional resistance, as the undeformed hollow profile, so that the cross member 15 in the middle section 30 is torsionally soft. The torsional stiffness in the middle section 30 is smaller than in a crank section 29 or end section 28 , This favors a different, in particular opposing compression of the vehicle wheels HR and is advantageous for driving stability and ride comfort.

The U or V profile is symmetrical with respect to a center line M. This includes with the vehicle vertical direction D an angle α in the range of 0 to 30 degrees. In addition, the profile between its legs on an opening angle γ of 5 ° to 40 °.

Furthermore, the center P of the cross-sectional profile in the middle section 30 opposite to the axis of rotation B and the wheel center Z against the forward direction of travel V backwards and downwards. The offset s against the forward direction of travel V is in a suitable for passenger vehicles rear axle 10 in the range of 20 to 200 millimeters, preferably in the range of 50 to 150 millimeters. The offset t in the vehicle vertical direction D is of the same order of magnitude, but is preferably smaller than the offset s in the longitudinal direction.

The folded profile cross section goes in the direction of the Kröpfungsabschnitts 29 continuously into a box-shaped profile shape over in 7 is shown. 6 shows an example of a transition form of the U or V-profile in the box shape. This transition takes place in the even rearwardly offset and straight portion of the cross member 15 ,

Starting from the middle section 30 is still before the actual crank and at the beginning of the range of the connection of the spring plate 18 reaches a box-shaped profile shape, where there the Profile extension h in the vehicle vertical direction D is less than or equal to the profile extension b in the forward direction of travel V. The ratio of profile height h to profile width b is preferably in the range from 1: 1 to 1: 2.

In the further course towards the end sections 28 of the crossbeam 15 the profile shape changes to the effect that the profile extension in the vehicle vertical direction is greater than the profile extension in the vehicle longitudinal direction.

8th shows a further section through the cross member 15 in the area of the cranking section 29 , and that at the point where the first joint 24 connected.

The latter has a hinge pin 31 on that through the cross member 15 is inserted through and attached to this. The hinge pin 31 extends in the direction of the longitudinal central axis C of the rear axle 10 and sticks out at the back of the cross member 15 out of this. He is both with the wall pointing in the forward direction 32 the cross-sectional profile as well as with the facing in the opposite direction wall 33 welded the cross-sectional profile. Other forms of attachment, such as a screw connection or riveting are also possible.

In the area of damper connection, that is in the area of the consoles 21 , the profile height h is already significantly greater than the profile width b, as in 9 is shown. There is also the corresponding trailing arm 11 connected. The ratio h: b reaches its maximum in this range. It is preferably in the range of 3: 2 to 3: 1.

In the further course beyond the trailing arm 11 increases the relative profile width again. At the same time, the hitherto substantially rectangular profile shape is in an oval shape, as in 10 is shown, which is a section through the cross member 15 in front of the wheel-side console 21 at the beginning of the final section 28 shows.

In the area of the end section 28 the oval shape goes into the 11 illustrated circular shape at the end 16 of the crossbeam 15 above. The axis of rotation B of the associated rear wheel HR or the wheel center Z is in the center of this circle, whereby an optimal wheel connection is achieved.

The above-described rear axle 10 Characterized by a support structure, which is assembled from a very small number of components. This results in a simple production and assembly and ultimately a cost-effective production. It is also characterized by a low component weight.

The rear wheels HR sit in front of the ends 16 of the crossbeam 15 , About the varying cross-sectional profile is on the one hand a particularly rigid design in the field of connection of the trailing arm 11 as well as the springs 19 and dampers 20 reached. On the other hand, the torsionally soft middle section 30 allows a defined elastic twisting in the nature of the action of a stabilizer, which is advantageous in a compression of the vehicle wheels.

In particular, by the above-explained rear axle 10 a great freedom of design for the area in front of the relatively far back on the vehicle crossmember 15 created. The through the rear axle 10 provided near-ground clearance 2 can be used for a variety of purposes, such as crash-proof storage of energy storage, accommodation of other vehicle components, or additional storage space. The between the trailing arms 11 and the cross member 15 Spanned free space is sufficient, apart from the spring plates 19 and the springs 18 to the cross member 15 and to the trailing arm 11 approach.

The invention has been explained above with reference to an embodiment. However, it is not limited thereto, but encompasses all embodiments defined by the claims.

LIST OF REFERENCE NUMBERS

1

motor vehicle

2

near-ground area from below the rear bench to the front of the cross member 15 the rear axle 10

10

rear axle

11

Trailing arm

12

front end section

13

Rubber bearing

14

rear end section

15

crossbeam

16

End of the cross member

17

wheel carrier

18

spring plate

19

feather

20

damper

21

console

22

Panhardstab

23

carrier

24

first joint

25

second joint

26

hinge pins

27

Rifle

28

End portion of the cross member 15

29

Kröpfungsabschnitt of the cross member 15

30

Middle section of the cross member 15

31

hinge pins

32

in the forward direction facing wall

33

in the opposite direction facing wall

A

Rotary axis of the trailing arm connection to the vehicle body

B

Rotary axis of a rear wheel

C

Longitudinal center axis of the rear axle

D

Vehicle vertical direction

MR

rear wheel

M

Profile center line

P

Middle of the cross section profile in the middle section 30

V

Forward direction

Z

wheel center

α

Angle between profile center line M and vehicle vertical direction D

β

Angle between the radial direction of the bush 27 and vehicle vertical direction D

γ

Opening angle of the profile cross section in the middle section 30

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10003230 A1 [0006]
• DE 102008045082 A1 [0008]

Claims (10)

Rear axle for a motor vehicle, comprising: two trailing arms ( 11 ) for coupling to a vehicle body, and a cross member ( 15 ), the trailing arm ( 11 ), wherein the cross member ( 15 ) at its ends ( 16 ) each having a cross-sectional profile which is penetrated by a rotational axis of a vehicle wheel, characterized in that the cross member ( 15 ) between its ends ( 16 ) is cranked against a forward direction of travel of the motor vehicle, and one of the trailing arms ( 11 ) and the cross member ( 15 ) spanned space at least in a band-shaped strip along the longitudinal central axis (C) of the rear axle ( 10 ) is designed as a free space. Rear axle according to claim 1, characterized in that the cross member ( 15 ) between its ends ( 16 ) Based on the forward direction at least partially behind the axes of rotation of the vehicle wheels runs. Rear axle according to claim 1 or 2, characterized in that the cross member ( 15 ) is a one-level hollow profile body with varying cross-sectional profile. Rear axle according to one of claims 1 to 3, characterized in that at the ends ( 16 ) end sections ( 28 ) of the cross member ( 15 ) each a Kröpfungsabschnitt ( 29 ) and between these offsets ( 29 ) a middle section ( 30 ) is arranged, wherein the cross member ( 15 ) has a closed hollow profile, which in the region of the Kröpfungsabschnitte ( 29 ) box-shaped, in the area of the middle section ( 30 ), however, is designed as a double-walled folded U or V profile. Rear axle according to claim 4, characterized in that the cross-sectional profile of the cross member ( 15 ) starting from the middle section ( 30 ) towards the end sections ( 28 ) Over an area in which the profile extension in the vehicle vertical direction is less than or equal to the profile extension in the vehicle longitudinal direction, merges into an area in which the profile extension in the vehicle vertical direction is greater than the profile extension in the vehicle longitudinal direction. Rear axle according to claim 4 or 5, characterized in that the U- or V-profile to a center line (M) is symmetrical and has an opening angle in the range of 5 to 40 degrees. Rear axle according to one of claims 1 to 6, characterized in that a Panhardstab ( 22 ) provided by a joint ( 24 ) coupled to the cross member ( 15 ), this joint ( 24 ) at one of the Kröpfungsabschnitte ( 29 ) of the cross member ( 15 ) is attached. Rear axle according to one of claims 1 to 7, characterized in that the longitudinal members ( 11 ) in the region of the cranking sections ( 29 ) and / or end sections ( 28 ) to the cross member ( 15 ) are connected. Rear axle according to one of claims 1 to 8, characterized in that at least one damper mount on a side facing away from the forward travel direction of the cross member ( 15 ) is formed or fastened, wherein the damper mount in the region of a Kröpfungsabschnitts ( 29 ) and / or an end section ( 28 ) is arranged. Motor vehicle with a rear axle according to one of claims 1 to 9.

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