DE102015210850A1 - Wheel suspension for a motor vehicle - Google Patents

Abstract

The invention relates to a wheel suspension (1) for a motor vehicle, comprising at least one wheel carrier (2) for receiving a wheel (3), a longitudinal carrier (4) as part of a vehicle body, and a spring (5). To provide a suspension with good spring properties and low weight available, the invention provides that an upper end (6) of the spring (5) in the region of the longitudinal member (4) is connected to the vehicle body and a lower end (7) of Spring (5) is connected to the wheel carrier (2), wherein the lower end (7) laterally of an installation position of the wheel (3) and disposed further outwardly than the upper end (6).

Description

The invention relates to a wheel suspension for a motor vehicle having the features of the preamble of claim 1.

In modern motor vehicles, all wheels are connected via a suspension with the body or the chassis of the vehicle. The respective wheel and a wheel carrier receiving this are part of the unsprung mass, which follows more or less the height profile of the respective running surface, while body and chassis form parts of the sprung mass, which should be at least largely decoupled from sudden movements of the unsprung mass. Various forms of springs are known in the art. In today's vehicles, above all, either coil springs (for example made of steel) or pneumatic springs are used. The effect of the springs is complemented by shock absorbers, which convert the energy of the movement between sprung and unsprung mass into heat and thus prevent unwanted vibration behavior. Since the motion of the sprung mass with respect to the unsprung mass is predominantly vertical, normally also springs and shock absorbers are oriented substantially vertically. In addition, the wheel carrier is connected to the chassis with more or less horizontally extending arms (eg wishbone or trailing arm). In addition to suspensions in which the spring is at least indirectly connected to the wheel, such designs are known in which the spring acts on a handlebar.

In view of the general requirement to reduce fuel consumption and CO ₂ emissions, the aim is currently to reduce the weight of the vehicle as possible, which in principle all components and components of the vehicle are affected. Also in the area of the wheel suspensions, the aim is to reduce the weight. Here, it is sometimes possible to construct individual components from lighter materials such as fiber-reinforced plastic. However, overall the possibilities of weight reduction are limited by the given architecture of the suspension.

The DE 27 30 323 shows a front wheel single suspension for a motor vehicle with a control arm, which is connected to a vehicle body supporting frame member and a steering knuckle, and a vertically disposed shock absorber, which is connected to the vehicle body and with the steering knuckle. The lower end of the shock absorber is located next to and below the axis of rotation of the wheel. A vertically arranged coil spring is supported on the one hand next to the upper end of the telescopic shock absorber and on the other hand on the steering knuckle or at the lower end of the telescopic shock absorber, essentially in the axis formed by the connection points of the control arm and telescopic shock absorber on the steering knuckle.

The EP 0 489 638 B1 shows a suspension for a steerable wheel of a motor vehicle, with an upper and a lower arm, which are on the one hand connected to the body of the vehicle and on the other hand form joints for the pivotal mounting of a wheel carrier. Furthermore, a shock absorber and a separate spring are provided, which is supported on the body and on the wheel carrier, wherein the spring is located above the wheel and extends approximately along the axis defined by the joints. Here, the wheel carrier has a bent around the inside of the wheel leading around curved part, at the upper end of the spring is received.

The BE 444 162 shows a suspension for motor vehicles with independently suspended wheels, which are respectively connected via upper and lower links to the chassis. All wheels are supported by coil springs which are substantially perpendicular and act on the top of the wheel carriers, being held on the upper side by arms fixedly connected to the chassis.

The FR 1 407 708 A discloses a suspension device for motor vehicles, comprising a steering knuckle carrier having an upper and a lower arm. To the upper arm of the steering knuckle is connected via a hingedly connected to the chassis handlebar and the lower arm via a force acting on the chassis coil spring. Furthermore, a shock absorber arranged outside the helical spring is connected, on the one hand, to the chassis and, on the other hand, to the handlebar.

The GB 2 100 201 A shows a suspension for vehicles with a telescopic hydraulic damper and a lower control arm, which is internally connected to the sprung mass and the outside with a wheel carrier, wherein the lower arm between its two ends is pivotally connected to the hydraulic damper. Furthermore, the suspension comprises an upper control arm pivotally connected to the hydraulic damper, a wheel support rotatably connected to the upper and lower control arms, and a spring disposed between the sprung mass and the wheel carrier. In particular, the spring can be connected on the one hand to the chassis and on the other hand to the hydraulic damper.

The FR 2 748 699 A1 shows a suspension with a coil spring, which is arranged above the wheel and is connected on the one hand to the chassis and on the other hand via an intermediate sleeve with an upper end of an upwardly leading, curved arm of the wheel carrier. A wishbone is pivotally connected to two axes extending in the longitudinal direction of the vehicle on the one hand to the chassis and on the other hand with said cuff.

The WO 2005/051687 shows an independent suspension for a motor vehicle wheel. Here are for connecting a wheel carrier to the chassis of the vehicle more wishbones in a lower transverse link plane and in an upper transverse link plane, which lies above the wheel, is provided. A suspension spring for the vehicle body is arranged above the wheel and attacks, for example, on an upwardly guided rigid arm of the wheel carrier.

The EP 0 412 322 A1 discloses a suspension of a steered wheel of motor vehicles, comprising a wheel carrier which is pivotally connected to the vehicle body by a lower link assembly and by an upper link assembly located above the steered wheel and articulated by means of a ball joint to an upper boom of the wheel carrier. Furthermore, on the one hand on the vehicle body and on the other hand supported on the wheel support spring device is provided, which is supported via an upper spring plate on the vehicle body and a lower spring plate and a rolling bearing in the ball joint on the wheel and spatially aligned so that the spring center axis through the ball center of the ball joint runs.

The DE 10 2004 058 698 B3 discloses a suspension with a vehicle body and on this via a handlebar assembly movably articulated wheel with a wheel. A helical compression spring is supported, on the one hand, on the vehicle body and, on the other hand, on the wheel carrier or on the handlebar arrangement, wherein the spring rigidity of the vehicle body support related to the point of contact of the wheel can be changed in a controlled manner. This is achieved, for example, in that a helical compression spring is used in which the force action line deviates from the geometric spring center line and the spring can be rotated in a controlled manner. In this case, in particular, an S-shaped helical compression spring can be used.

The EP 2 374 639 B1 discloses a torsion beam axle having two drawn longitudinal wings connected by a tread, each longitudinal wing being associated with a coil spring which is supported at its lower end to the longitudinal rocker and at its upper end to a vehicle body. The coil spring is mounted inclined between upper and lower spring bearings and arranged so that the force line of action has a different inclination angle during compression and rebound. An upper piercing point of the force line of action by an upper spring bearing is located closer to the spring centerline with respect to a lower piercing point of the force line of action by a lower spring bearing, the two piercing points being located opposite to the spring center line and the force action line being more inclined during compression on a bend outside during compression is as on a curve inside the rebound.

The KR 10 2004 0012 400 A1 discloses a coil spring for suspensions in vehicles. Here, the diameter of the material used for the coil spring alternates between a first and a second diameter. The first diameter material is positioned on one side of the spring and the second diameter material on the other side. As a result, the center axis of the coil spring can be matched to a load axis.

The development of a suspension with good spring properties and low weight still offers room for improvement in view of the prior art shown. In particular, the weight of the spring should be reduced, without this having a negative effect on their performance.

The invention is therefore an object of the invention to provide a suspension with good spring properties and low weight available.

According to the invention the object is achieved by a suspension with the features of claim 1, wherein the dependent claims relate to advantageous embodiments of the invention.

It should be noted that the features listed in the following description as well as measures in any technically meaningful way can be combined with each other and show other embodiments of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures.

The invention provides a wheel suspension for a motor vehicle. As motor vehicles in particular cars or trucks come into question. It may be the suspension of a front wheel or a rear wheel. The suspension has a wheel carrier for receiving a wheel, a side member as a part a vehicle body and a spring on. The wheel or axle takes on the actual axis of rotation of the wheel, which is thus rotatably mounted in the installed state with respect to the same. The longitudinal beam forms part of the vehicle body or vehicle frame and extends substantially in the longitudinal direction or along the X-axis of the vehicle. The spring is used to decouple the sprung mass, part of which is the side member of the unsprung mass, part of which is the wheel carrier. It can in principle assume any design that is known in the art.

According to the invention an upper end of the spring in the region of the longitudinal member is connected to the structure and a lower end of the spring is connected to the wheel carrier, wherein the lower end is arranged laterally of an installation position of the wheel. Preferably, the upper end is connected (at least indirectly) to the side member. The compounds mentioned are usually given in such a way that the spring is supported on the longitudinal member or on the wheel and is held there in the operating state by its bias, where it is z. B. is accommodated in a kind of spring plate, which in turn is attached to the side member or on the wheel. The connection can thus be provided indirectly by an intermediate spring receptacle (eg spring plate).

The lower end of the spring is the same with built-in wheel laterally, ie along the Y-axis next to the wheel and along the Z-axis at the level of the wheel. It is thus deeply positioned. In this way, on the one hand, despite the usually relatively low position of the longitudinal member, a relatively long spring can be used. This means that the maximum possible spring travel in the operating state in relation to the total length of the spring is smaller. In particular, it is easier to prevent that the spring is fully compressed in the operating state. However, the present design also allows a relatively large ratio of spring travel of the spring to travel of the wheel. This large ratio of travel of the spring to spring travel of the wheel is achieved in that the lower end of the spring is connected directly to the wheel. This, in turn, is crucial for weight savings since, with a longer spring travel, the spring can generally be made lighter due to the lower static load.

In particular, the upper end of the spring can be arranged on an underside of the longitudinal member. Alternatively, it may also be arranged laterally of the longitudinal member. Preferably, the upper end of the spring is arranged offset directly below the longitudinal member or directly below the longitudinal member in the lateral direction (ie in the Y direction) to the vehicle outer side.

According to the invention, the lower end of the spring is arranged on the outside than the upper end. In other words, the spring, when viewed from top to bottom, is inclined outwards. Of course, "outside" refers to a position that is farther from the center of the vehicle with respect to the Y-axis and closer to the wheel carrier Note that due to its inclination, the spring absorbs not only forces in the Z direction (ie perpendicular), but also forces in the Y direction. because the lower end of the spring can be connected directly to the wheel, which is also desirable under the above-mentioned aspect of weight saving.

Advantageously, the lower end of the spring is arranged lower than a rotational axis of the wheel. In this way, even with a relatively low position of the longitudinal member relative to the wheel carrier enough space for the installation of the spring, u.a. also an excessive inclination of the spring can be avoided. Too strong an inclination would on the one hand the main function of the spring, namely the absorption of vertical forces, impaired, on the other hand, the mediated by the spring lateral forces may be too strong. The wheel carrier may in this embodiment have a kind of lower arm, on which the lower end of the spring is supported.

To at least partially decouple the amount of laterally acting forces from the skew of the spring, it is preferred that a force line of action of the spring be at an angle to a centerline of the spring. The center line or spring center line corresponds with a cylindrical coil spring of the cylinder axis. For non-cylindrical springs, in which z. For example, if the individual coils have different diameters and / or are offset from one another, a kind of center of each individual coil is normally constructed and said centers are connected by an imaginary line which then forms the center line. While the center line in the unloaded state may possibly be curved, springs known in the prior art are normally designed such that a straight center line exists in the unloaded state.

According to one embodiment, the force line of action is more inclined to the vertical than the center line. In other words, the Inclination of the force of action line is greater by this configuration. Thus, at a given installation position of the spring, the lateral rigidity of the suspension can be improved as the spring receives more lateral forces (along the Y-axis). This can have a positive effect on driving behavior and stability, especially when cornering.

On the other hand, in some cases too much skew of the force line of action may lead to undesirable preloads in some bushings of the suspension. This is due to the already mentioned lateral force component. To mitigate this effect, in an alternative embodiment, the force line of action may be less inclined to the vertical than the center line. Of course, this also includes the case that the force line of action is perpendicular, while the center line is inclined with respect to the vertical.

Furthermore, the inclination of the force line of action of the spring can also be used to selectively influence or optimize the driving stability and the self-steering behavior under spring deflection.

Basically, the spring can be realized by different tree shapes, for example. As a pneumatic spring. According to another embodiment, the spring is designed as a helical spring. It typically consists of spring steel or fiber composite plastic. In the simplest embodiment, the spring is in a relaxed state straight and cylindrical. In addition, however, there are also designs in question in which, for example, the radius of curvature of the individual turns varies or the center line is curved in a relaxed state. According to such an embodiment, the spring is S-shaped. This refers to the shape of the spring or its center line in a relaxed state. As noted above, such springs are normally straight in the tensioned state. However, in the tensioned state, they have a force action line that does not coincide with the center line but is at an angle to it. A similar effect can be achieved with pneumatic springs with a rolling bellows made of a fiber-rubber composite. In this case, an angled to the geometric center line of the pneumatic spring force line of action is achieved by the asymmetric design of the rolling bellows.

Further advantageous details and effects of the invention are explained in more detail below with reference to an embodiment shown in the figure. It shows

1 a schematic representation of a suspension according to the invention.

1 shows a schematic representation of a suspension according to the invention 1 of a motor vehicle, for example a passenger car. The plane of the drawing here corresponds to the YZ plane of the vehicle. A wheel 3 This is an axis 11 rotatable on a wheel carrier 2 stored. The wheel carrier 2 is on the vehicle side connected via handlebar, not shown here with a vehicle body, to which also a longitudinal member 4 belongs. A coil spring 5 , which consists for example of spring steel, is supported by an upper end 6 from the side member. With a lower end 7 she leans on a boom 8th of the wheel carrier 2 from. The lower end 7 as well as the boom 8th are located next to the bike 3 and are located much lower than the axis of rotation 11 of the wheel 3 , Due to the arrangement of the lower end 7 on the wheel carrier and due to a slight inclination of the spring 5 in which the lower end 7 is arranged further out than the upper end 6 , The spring travel of the coil spring is about as large as that of the wheel 3 more precisely, due to kinematic and elastokinematic effects, slightly smaller. By this ratio of the spring travel and the resulting relatively low static load, the coil spring 5 relatively compressible or "soft" running, which in turn means that they can be comparatively easy. This has a positive effect on the overall weight and thus on the fuel consumption of the vehicle.

Also marked is a midline 9 the coil spring 5 , In a conventional spring this corresponds to the force line of action. Due to the slightly oblique force line of action, lateral forces are transmitted in addition to the vertical forces arising during compression, which can have an advantageous effect on the driving stability.

Alternatively, a coil spring 5 are used, which in the relaxed state is S-shaped, so that one opposite the center line 9 inclined force line of action 10.1 . 10.2 results. The figure shows an example of a force action line 10.1 , which is less inclined to the vertical than the midline 9 , This almost no lateral forces are transmitted, which on the one hand reduce the driving stability, on the other hand, but can prevent certain suspension components through the lateral components of the force of the coil spring 5 be charged in an undesirable manner.

Furthermore, the figure shows a force line of action 10.2 which is more inclined than the midline 9 , As a result, the lateral stabilization effect is further enhanced, but without the inclination the coil spring 5 to have to change. Basically, the different force lines could 10.1 . 10.2 with one and the same coil spring 5 be realized, which would have to be rotated by 180 °.

It is understood that the suspension 1 may include, in addition to the components shown yet further, in particular a shock absorber, either within the coil spring 5 or may be arranged outside thereof.

LIST OF REFERENCE NUMBERS

1

 Arm

2

 wheel carrier

3

 wheel

4

 longitudinal beams

5

 coil spring

6

 top end

7

 lower end

8th

 boom

9

 center line

10.1, 10.2

 Line of action

11

 axis of rotation

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 2730323 [0004]
• EP 0489638 B1 [0005]
• BE 444162 [0006]
• FR 1407708 A [0007]
• GB 2100201 A [0008]
• FR 2748699 A1 [0009]
• WO 2005/051687 [0010]
• EP 0412322 A1 [0011]
• DE 102004058698 B3 [0012]
• EP 2374639 B1 [0013]
• KR 1020040012400 A1 [0014]

Claims (7)

Wheel suspension ( 1 ) for a motor vehicle, at least comprising - a wheel carrier ( 2 ) for receiving a wheel ( 3 ), - a longitudinal beam ( 4 ) as part of a vehicle body, and - a spring ( 5 ) characterized in that an upper end ( 6 ) the feather ( 5 ) in the region of the longitudinal member ( 4 ) is connected to the vehicle body and a lower end ( 7 ) the feather ( 5 ) with the wheel carrier ( 2 ), the lower end ( 7 ) laterally of an installation position of the wheel ( 3 ) and located further outward than the upper end ( 6 ). Wheel suspension according to claim 1, characterized in that the lower end ( 7 ) the feather ( 5 ) lower than a rotation axis ( 11 ) of the wheel ( 3 ) is arranged. Wheel suspension according to one of the preceding claims, characterized in that a force line of action ( 10.1 . 10.2 ) the feather ( 5 ) at an angle to a center line ( 9 ) the feather ( 5 ) runs. Wheel suspension according to one of the preceding claims, characterized in that the force line of action ( 10.2 ) is more inclined to the vertical than the center line ( 9 ). Wheel suspension according to one of claims 1 to 3, characterized in that the force line of action ( 10.1 ) is less inclined to the vertical than the midline ( 9 ). Wheel suspension according to one of the preceding claims, characterized in that the spring ( 5 ) is designed as a helical spring. Wheel suspension according to claim 6, characterized in that the spring ( 5 ) Is S-shaped.

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