DE102018123443B4 - Axle suspension with double wishbones - Google Patents

Abstract

Axle suspension (1) for a motor vehicle (2), in particular an electric motor vehicle, a vehicle wheel (9) being coupled to an axle auxiliary frame (3) and / or a vehicle body via a double wishbone suspension on each side, characterized in that a wishbone made of fiber composite material is used as a spring wishbone (4) and is firmly coupled on the vehicle side, a wheel carrier (8) being arranged on the wheel side and the wheel carrier (8) being coupled to the wheel-side end of the spring control arm (4) and to the wheel-side end of the second control arm (5), each with one degree of freedom (10).

Description

The present invention relates to an axle suspension for a motor vehicle according to the features in the preamble of claim 1.

Various axle suspensions are known from the prior art. For this purpose, an axle is coupled either directly to the motor vehicle body or also, at least partially, to an axle auxiliary frame by means of links.

A McPherson wheel suspension is known, for example. Here a lower wishbone is coupled to an auxiliary axle frame. The lower wishbone is then connected to a wheel carrier at its wheel-side end. A vehicle wheel is rotatably coupled to the wheel carrier. A shock absorber is also coupled in the upper region of the wheel carrier so that the wheel carrier is now also defined in the transverse direction of the motor vehicle and is kept following the deflection or rebounding process of the wheel. Usually a helical compression spring is then attached to the shock absorber, which absorbs the static and dynamic wheel load.

From the DE 10 2013 209 648 A1 such a suspension is known. However, no helical compression spring is coupled in the upper region of the shock absorber in a spring strut dome of a motor vehicle body. Rather, a leaf spring is provided here, which is coupled to an axle auxiliary frame on the body side and is coupled to the lower wishbone.

A disadvantage of this arrangement, however, is that the shock absorber located above and the design of the leaf spring require a corresponding overall height of this vehicle wheel suspension.

From the generic DE 10 2014 102 541 A1 is known an axle suspension with double wishbones on an electric motor vehicle. In addition to the double wishbones, a transverse leaf spring is arranged here. From the DE 10 2016 207 631 A1 the torque-fixed connection of two transverse leaf springs to a wheel carrier is disclosed in a McPherson axle.

The object of the present invention is to provide a wheel suspension which implements a simplified construction and a low construction height with regard to the vehicle body.

The aforementioned object is achieved according to the invention in an axle suspension with the features in claim 1.

Advantageous embodiments of the present invention are the subject of the dependent claims.

In the case of an axle suspension for a motor vehicle, which is particularly suitable for an electric motor vehicle, the invention provides that a vehicle wheel is arranged on each side. The respective vehicle wheel is connected to the motor vehicle via a double wishbone suspension. There are therefore two wishbones on each side. A respective wishbone is either coupled to an axle subframe or the vehicle body. A frame structure can also be used. Both wishbones can be coupled with an auxiliary axle frame. However, both wishbones can also be coupled to the vehicle body. It is also possible to couple a lower wishbone to an axle auxiliary frame and an upper wishbone to a vehicle body.

According to the invention, the axle suspension is characterized in that a wishbone made of fiber composite material is designed as a spring wishbone, which can also be referred to as a resilient wishbone. This spring wishbone is coupled firmly clamped on the vehicle side. According to the invention, a separate spring, in particular a helical compression spring, an air spring, but also a separate leaf spring, can thus be dispensed with. The spring control arm thus takes over the function of the spring and works on the principle of a leaf spring with one-sided clamping. At the same time, the spring wishbone also assumes a wheel guidance function, so that it not only absorbs forces in the vertical direction of the motor vehicle, but also forces in the transverse direction of the motor vehicle and in the longitudinal direction of the motor vehicle. The spring control arm is thus the suspension spring of the motor vehicle. In particular, the spring control arm is made of fiber composite material. Thus, it can deform while exerting a spring force, in particular to absorb the static and dynamic wheel loads in the vertical direction of the motor vehicle. The spring wishbone is designed in particular as a component which is flat in the vertical direction of the motor vehicle and a component which is significantly wider in relation to the longitudinal direction of the motor vehicle. Because the spring wishbone is firmly clamped on the vehicle side, the wheel-side end can then move up and down, in particular in the vertical direction of the motor vehicle, and thus provide the corresponding spring force for absorbing static and dynamic wheel loads.

As a result of the fact that an additional spring, in particular a coil spring or air spring, is dispensed with in the axle suspension according to the principle of a double wishbone arm, the entire axle suspension has a low construction height in the vertical direction of the motor vehicle. In particular is the construction height is less than 500 mm, in particular the construction height is less than or equal to 400 mm. However, the axle suspension should have a height of more than 200 mm and in particular more than 300 mm.

For the purposes of the invention, a wheel carrier is thus arranged on the wheel side. The wheel carrier is coupled to the respective wheel-side end of each wishbone. In particular, coupling with one degree of freedom of rotation is provided here. For example, rubber-metal bearings can be used. The wheel carrier can thus maintain the required camber or the kinematic coupling during the spring-in or spring-out movement.

An additional pivot bearing can also be arranged on the wheel carrier side, preferably with a degree of freedom of rotation about the vertical axis. The axle suspension according to the invention can thus be used as a steerable axle suspension, in particular as a front axle.

In a further preferred embodiment variant, the spring control arm is installed at the top in relation to the vertical direction of the motor vehicle. This offers the advantage that, in particular, any stone chips that occur in the underfloor area of the motor vehicle, which could cause damage to the fiber composite material if the motor vehicle has been used for years. However, it is also possible within the scope of the invention to install the spring control arm at the bottom in relation to the vertical direction of the motor vehicle.

The second wishbone is made of a metallic material. It can also be a wishbone, for example. As already mentioned at the beginning, this is coupled to the wheel carrier on the vehicle side with a degree of freedom of rotation.

Particularly preferably, the second wishbone is also coupled on the vehicle side with a degree of freedom of rotation, in particular via two bearings which are offset from one another in the longitudinal direction of the motor vehicle. The second wishbone can be a triangular link, but also, for example, a single link or two single links, which are then arranged on each side of the vehicle in addition to the spring control arm.

In order to further minimize the installation height in particular, a shock absorber is integrated into the axle suspension on each side.

This is in particular carried out in such a way that the shock absorber is coupled on the vehicle side in the area of the fixed clamping of the spring control arm and is coupled on the wheel side to the second control arm. The shock absorber is thus related to the vertical direction of the motor vehicle, not via the axle suspension. The shock absorber is thus preferably installed obliquely in the vertical direction of the motor vehicle. Particularly preferably with an angle between 10 and 60, particularly preferably between 15 and 45 degrees.

In particular, the shock absorber is coupled to the second wishbone in such a way that it is coupled with respect to a length of the second wishbone coming from the vehicle-side end of the second wishbone in the range from 1/4 to 1/2 the length of the wishbone.

The axle suspension according to the invention can particularly preferably be installed in the region of a front axle of a motor vehicle and in particular of an electric motor vehicle. The fact that no internal combustion engine is installed in the front end of the electric motor vehicle means that the overall height is lower than that of conventional motor vehicles that are operated with internal combustion engines. It can therefore in particular be a steered front axle. The wheel carrier is then coupled to the wishbones at the wheel-side ends by a further degree of freedom of rotation. This further degree of freedom of rotation rotates in particular about the vertical direction of the motor vehicle, so that the steering movement can be carried out to turn the front wheels.

As a further preferred refinement of the present invention, provision is made for the vehicle-side fixed clamping of the spring control arm to be adjustable. This is designed such that the vehicle height can be adjusted with a static wheel load. A kind of level regulation can therefore be carried out. For example, if the vehicle is to be placed higher or lower in the vertical direction of the motor vehicle, the fixed clamping can be adjusted and the height of the motor vehicle body relative to the road surface can thereby be adjusted.

• 1 eine Vorderansicht auf eine Seite einer erfindungsgemäßen Achsaufhängung mit oben angeordnetem Federquerlenker,
• 2 eine Vorderansicht auf eine Seite einer Achsaufhängung mit unten angeordnetem Federquerlenker,
• 3a bis d einen erfindungsgemäßen Federquerlenker in verschiedenen Fahrsituationen,
• 4a und b eine Draufsicht und eine _Seitenansicht eines Federquerlenkers,
• 5 eine Draufsicht auf eine erfindungsgemäße Achsaufhängung mit unten angeordnetem Federquerlenker und oben angeordnetem zweiten Querlenker als Dreiecksquerlenker,
• 6 eine Frontansicht gemäß 5,
• 7 eine Draufsicht auf eine erfindungsgemäße Achsaufhängung mit oben angeordnetem zweiten Querlenker als Stabquerlenker,
• 8 eine Frontansicht gemäß 7 und
• 9 eine Frontansicht mit oben angeordnetem Federquerlenker und unten angeordnetem zweiten Querlenker als Einzelstablenker.

Further advantages, features, properties and aspects of the present invention are the subject of the following description. Preferred design variants are shown in schematic figures. These serve to simplify the understanding of the invention. Show it

• 1 2 shows a front view on one side of an axle suspension according to the invention with a spring control arm arranged at the top,
• 2nd a front view of one side of an axle suspension with spring control arm arranged below,
• 3a to d a spring control arm according to the invention in different driving situations,
• 4a and b are a top view and a side view of a spring control arm,
• 5 1 shows a plan view of an axle suspension according to the invention with a spring wishbone arranged at the bottom and a second wishbone arranged at the top as a wishbone wishbone,
• 6 a front view according to 5 ,
• 7 a plan view of an axle suspension according to the invention with a second wishbone arranged above as a rod wishbone,
• 8th a front view according to 7 and
• 9 a front view with a spring control arm arranged at the top and a second control arm arranged at the bottom as a single rod control arm.

The same reference numerals are used in the figures for identical or similar components, even if a repeated description is omitted for reasons of simplification.

1 shows an axle suspension according to the invention 1 . Here is only one side of a motor vehicle 2nd shown in front view, a second page would result, for example, in mirror image. Here is an axle subframe 3rd shown. This can be, for example, the front-end structure of an electric motor vehicle. It can also be a general frame structure that is produced, for example, by extrusion.

On the axle subframe 3rd a spring wishbone is arranged at the top 2nd and arranged below a second wishbone 5 each shown on the vertical direction Z of the motor vehicle. The second wishbone 5 is on the vehicle side with a degree of freedom of rotation 6 with the axle auxiliary frame 3rd coupled. Furthermore, it is on the wheel side with a degree of freedom of rotation 7 with a wheel carrier 8th coupled. To the wheel carrier 8th is a vehicle wheel rotatable 9 coupled.

According to the invention, the spring control arm is now referenced above to the vertical direction Z of the motor vehicle 4th arranged. The spring control arm 4th itself is on the wheel side with a degree of freedom of rotation 10th with the wheel carrier 8th coupled. The suspension arm is on the vehicle side 4th firmly clamped with the axle auxiliary frame 3rd , also connected to the entire vehicle frame.

Now becomes a static or dynamic force F introduced into the wheel carrier, so there is a relative displacement of the auxiliary axle frame 3rd to the vehicle wheel 9 , based on the vertical vehicle direction Z instead. The lower second wishbone 5 takes over a pure kinematic coupling and in particular wheel guidance in the motor vehicle transverse direction Y. The upper spring control arm 4th develops a spring force at its wheel-side end due to the fixed vehicle-side clamping 11 . The spring control arm 4th also takes over the wheel guidance in the vehicle longitudinal X and transverse direction Y.

The spring control arm 4th is according to 3a to d deformed accordingly. 3a shows the spring control arm 4th in an unloaded and unassembled state of delivery. 3b shows the spring control arm 4th in installed condition. Here it is firmly clamped on the vehicle side and with a fixed clamp 11 connected to the motor vehicle, not shown. On the wheel side, it has a bearing with a degree of freedom of rotation 10th coupled with the wheel carrier, not shown. The static wheel load acts F _S on the spring control arm 4th , so that it differs from the delivery state 3a deformed under the development of a spring force. Now becomes an additional dynamic wheel load F _d upset, this is in 3c shown, which leads to a further deformation of the spring control arm 4th leads to the motor vehicle vertical direction Z upwards. This reflects a deflection process. In 3d a rebound process is then shown. The spring control arm thus works according to the technical principle of a cross leaf spring.

Furthermore, in 1 shown that a shock absorber 12 in the axle suspension 1 arranged. For this purpose, there is an upper end related to the vertical direction Z of the motor vehicle 13 of the shock absorber 12 in the area of fixed clamping 11 of the spring control arm Z arranged, preferably with a degree of freedom of rotation. A lower end related to the automotive vertical direction 14 of the shock absorber 12 is with the second wishbone 5 coupled. In particular, there is always one end of the shock absorber 12 with the second wishbone 5 coupled. The vehicle-side connection of the shock absorber 12 can also, for example, on the axle auxiliary frame 3rd or a frame element.

Based on the length L , hence the total length of the second wishbone 5 is the shock absorber 12 with the second wishbone 5 in the range of 1/4 to 1/2 of the length L coupled. The shock absorber 12 is thus at an angle with respect to the vertical direction Z of the motor vehicle α arranged.

According to the invention, it is therefore possible to have a height 15 , hence the total height of the axle suspension 1 less than 500 mm.

Because of the fixed clamping 11 is preferably adjustable, the motor vehicle 2nd with static wheel load at vehicle height. Hence the distance 16 to the road surface 17th changed or discontinued and the motor vehicle 2nd be placed higher or lower.

2nd shows an embodiment variant similar to 1 , here the spring control arm 4th with respect to the motor vehicle vertical direction Z is arranged below and the second wishbone 5 based on the vertical vehicle direction Z above. So here is the shock absorber 12 also at an angle α arranged to the vertical direction Z of the motor vehicle. A bottom end 14 the shock absorber is in the area of the fixed clamping 11 of the spring control arm 4th arranged. An upper end 13 is with the second wishbone 5 coupled. Again, based on the length is preferred L the second wishbone the shock absorber 12 in a range of 1/4 to 1/2 with the second wishbone 5 coupled.

Furthermore struts or reinforcement struts 18th in 2nd shown. So here, for example, the axle subframe 3rd produced as a frame element, for example as a front or rear structure, this can be produced for example by extrusion. The struts are thus also made of the same material.

4a and 4b show a spring control arm 4th in top view and side view. In the area related to the image plane on the left when connecting to an auxiliary axle frame 3rd , the spring control arm 4th a greater thickness D3 in relation to the side of a wheel carrier 8th , related to the image plane on the right. The spring control arm 4th is preferably trapezoidal in plan view. Here again it refers to the image plane, on the left a greater width than on the side of a wheel carrier 8th . The width B8 is therefore smaller than the width B3 . The fat D8 is also smaller than the thickness D3 . 5 shows a plan view of an axle suspension according to the invention 1 . The spring control arm 4th is arranged below in relation to the vertical direction Z of the motor vehicle. Then there is a second wishbone on top 5 arranged as a wishbone. The wishbone is with a respective degree of freedom of rotation 6 arranged on the vehicle side, further with a further degree of freedom of rotation 7 on the wheel carrier 8th . Also clearly visible in the front view 6 is that the shock absorber 12 with a lower end 14 in the area of the vehicle frame or the fixed clamping of the spring control arm 4th is arranged and with its upper end 13 in the area of the wheel carrier 8th or at the outer end of the wishbone.

7 shows an alternative embodiment. The spring control arm is also related to the vertical vehicle direction Z here 4th arranged below and the second wishbone 5 arranged in the form of a rod link or single link. In this case it is possible to do so according to 8th at the upper end 13 of the shock absorber 12 at any length of the second wishbone 5 to arrange.

9 shows an alternative embodiment. Here is the end of the frame 13 of the shock absorber 12 not in the area of the coupling point of a handlebar or the fixed clamping 11 of the spring control arm 4th arranged, but on the frame structure itself.

Reference symbol list

1 -

Axle suspension

2 -

Motor vehicle

3 -

Axle subframe

4 -

Suspension arm

5 -

second wishbone

6 -

Degree of freedom of rotation

7 -

Degree of freedom of rotation

8th -

Wheel carrier

9 -

Vehicle wheel

10 -

Degree of freedom of rotation

11 -

fixed clamping

12 -

Shock absorber

13 -

top end too 12

14 -

bottom end too 12

15

height

16

distance

17th

Road surface

D3

thickness

D8

thickness

B3

width

B8

width

Y -

Motor vehicle cross direction

Z -

Motor vehicle vertical direction

F -

force

F _S -

static wheel load

F _d -

dynamic wheel load

L

Length too 12

Claims (9)

Axle suspension (1) for a motor vehicle (2), in particular an electric motor vehicle, with each A vehicle wheel (9) is coupled to an axle auxiliary frame (3) and / or a vehicle body via a double wishbone suspension, characterized in that a wishbone made of fiber composite material is designed as a spring wishbone (4) and is firmly coupled on the vehicle side, with a wheel carrier ( 8) and the wheel carrier (8) is coupled to the wheel-side end of the spring control arm (4) and to the wheel-side end of the second control arm (5), each with a degree of freedom (10). Axle suspension (1) according to claim, characterized in that the spring control arm (4) works according to the technical function of a leaf spring. Axle suspension after Claim 1 or 2nd ,, characterized in that the spring control arm (4) is installed at the top in relation to the vertical direction of the motor vehicle or that the spring control arm (4) is installed at the bottom. Axle suspension (1) according to Claims 1 to 3rd , characterized in that the second wishbone (5) is made of a metallic material, preferably a steel material. Axle suspension (1) according to Claims 1 to 4th , characterized in that a shock absorber (12) is incorporated on each side. Axle suspension (1) after Claim 5 characterized in that the shock absorber (12) on the vehicle side is coupled in the area of the fixed clamping (11) of the spring control arm (4) and on the wheel side is coupled to the second control arm (5), the shock absorber (12) is preferably connected to the second control arm ( 5) coupled in a range from 1/4 to 1/2 the length of the second wishbone (5), starting from the vehicle-side end. Axle suspension (1) according to Claims 1 to 6 , characterized in that the height (15) of the axle suspension (1) in the vertical vehicle direction (Z) is less than 500 mm, in particular less than or equal to 400 mm. Axle suspension (1) according to Claims 1 to 7 , characterized in that it is a front axle suspension, the wheel carrier (8) being coupled on the wheel side to both wishbones by a further degree of freedom of rotation. Axle suspension (1) according to Claims 1 to 8th , characterized in that the fixed clamping (11) of the spring control arm (4) is adjustable in such a way that the vehicle height with static wheel load (FS) is adjustable.

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