Spring arrangement for a motor vehicle

Abstract

Spring assembly (1) for a motor vehicle, comprising a coil spring (2) extending along an axis of extension (A) and a rubber-elastic spring support (3, 5) for indirectly supporting the coil spring (2) on a spring seat (10, 11), wherein at least one intermediate element (4) is arranged between the coil spring (2) and the spring support (3, 5), which bears against the coil spring (2) on one side and, in the unloaded state, bears against the spring support (3, 5) with a radially extending first contact area (4.4), wherein the intermediate element (4) bears against the coil spring (2) with a radially extending second contact area (4.6), characterized in that the intermediate element (4) has a base section (4.1) and two claw-like flange sections (4.2, 4.3) projecting from it, as well as a recess (4.5) located between them, which is smaller in dimension than a spring wire to be received therein. (2.2) of the coil spring (2), wherein surfaces of the intermediate element (4) adjacent to the recess (4.5) form the second contact area (4.6), which radially from the inside and from the outside with its claw-like flange sections (4.2, 4.3) encompassing the spring wire (2.2) bears against the spring wire (2.2) under preload and wherein rounded areas (4.7, 4.8) are arranged laterally to the first, planar contact area (4.4) and wherein at least one reinforcing element (6) is embedded in and enclosed by the intermediate element (4).

Description

[0001] The invention relates to a spring arrangement for a motor vehicle having the features of the preamble of claim 1.

[0002] The suspension is an essential element of the wheel suspension in motor vehicles. In a typical design, a wheel carrier, which forms the mount for the actual vehicle wheel, is connected to the vehicle chassis via one or more links (e.g. wishbones and trailing arms). The actual suspension can be ensured in a variety of ways. In each case, the spring is arranged in such a way that a restoring force is produced when the wheel carrier moves relative to the vehicle body. The vehicle body is part of the sprung mass, while the wheel carrier is part of the unsprung mass. In the prior art, coil springs are often used, which are usually made of spring steel. Such a coil spring is usually supported on the one hand either on the wheel carrier itself or on a link, and on the other hand on the vehicle body (i.e. the body or the chassis).The spring's course can be more or less vertical, but under certain circumstances there may also be a significant inclination in the longitudinal or transverse direction of the vehicle.

[0003] The respective area in which the spring is supported (wheel side or body side) is often referred to as the spring seat. In the prior art, for example, it is known to mount the spring in spring plates, which serve to provide a sufficiently large and flat contact surface for the spring, with the edge of the spring plate often being flange-like and enclosing the end of the spring to prevent lateral displacement. In this case, the spring is often not supported directly on a metal part (e.g. the spring plate), but rather a spring pad made of an elastic material, e.g. rubber, is arranged between them and serves to dampen vibrations. Especially in vehicles in the premium sector, it is an essential quality feature that vibrations emanating from the chassis are not transmitted to the body, or are transmitted to the body to the smallest possible extent.The springs represent a primary transmission path for noise and vibrations. Effective damping of vibrations at the transition between the spring and the spring seat, especially from the spring to the vehicle body, is therefore of central importance from an NVH (noise, vibration, harshness) perspective. However, current suspension systems, despite the interposition of an elastic spring base, cannot satisfactorily dampen such vibrations, at least in some frequency ranges.

[0004] DE 10 2007 050 084 A1 discloses a support for a helical compression spring on a wheel control arm, on which a cup is supported when installed. A plate, which is supported on the helical compression spring when installed, is in turn supported on the cup via an elastically flexible annular body, which, on the one hand, directly contacts the plate at a contact surface on the plate side and, on the other hand, directly contacts the cup at a contact surface on the cup side. Both the plate-side contact surface and the cup-side contact surface are designed to form a surface segment of a cone or a sphere.

[0005] JP H09-269027 A discloses a coil spring isolator arranged between a coil spring of a vehicle suspension and a spring seat supporting the coil spring. It consists of a laminated body composed of an annular vibration-damping rubber plate and a layer with high sliding properties. The layer is secured in an annular groove formed on the spring seat. A circumferentially extending recess is formed on one end surface of the vibration-damping rubber plate. One end of the coil spring is held in the recess. A low frictional resistance exists between the layer and the spring seat to generate sliding therebetween. Since the frictional resistance is low, abnormal noise generated by the displacement of the rubber and metal parts and positioning at the time of assembly are facilitated.

[0006] DE 10 2011 051 430 A1 relates to a support device for mounting a spring element on a damper body, in particular for a spring strut of a motor vehicle, comprising a support element with an opening for receiving the damper body, a contact area for supporting the spring element, and a holding area for supporting the support element on a holding element. The support element comprises a plastic material and can be positioned on the damper body by means of the holding element. The contact area is at a radial distance from the opening, and the holding area extends radially away from the opening. The radial distance of the contact area from the opening is greater than the radial extent of the holding area.

[0007] DE 196 32 184 A1 relates to a spring strut for motor vehicles, which is installed between the vehicle body and a wheel guide component and consists of a vibration damper and a helical compression spring surrounding the vibration damper. The helical compression spring rests on a spring plate firmly connected to a housing of the vibration damper, and on a second spring plate, preferably arranged on the vehicle body, with an elastic support arranged between the spring plate and the end of the helical compression spring for noise insulation. This support consists of at least two layers of recyclable and elastic material arranged one above the other in the axial direction of the spring plate.

[0008] US 2010 / 0 109 428 A1 discloses a device for damping vibrations of a coil spring, wherein a retaining device partially surrounds the end coil of the coil spring. The retaining device can be formed in one or two parts and comprises an annular flange arranged outside the end coil and a plurality of elastic claws arranged inside, forming a snap mechanism that secures the end coil in its position and thus prevents vibrations.

[0009] US 2014 / 0 265 081 A1 discloses an elastic cushion, e.g. made of rubber, that can be arranged between a spring seat and a coil spring and serves to protect the end of the spring from damage and contamination. The cushion comprises a seat section that is circularly arc-shaped and arranged axially in front of the spring, as well as two lateral wall sections that extend from the seat section. At least one wall section has a circular arc-shaped contact surface with which it rests against the coil spring, as well as an inclined surface sloping in the radial direction, which is intended to allow dirt to slide off. In the relaxed state, the radius of the contact surface is smaller than the radius of the wire of the coil spring.

[0010] US 2015 / 0 096 536 A1 discloses a pulse damper that is connected to a fuel line to absorb pulse pressure waves within the line. The pulse damper comprises a low-pressure coil spring and a high-pressure disc spring, which are arranged together with a spring guide shaft that can be moved back and forth inside a spring body, as well as a low-pressure spring cover arranged between the low-pressure coil spring and the high-pressure disc spring, and a high-pressure spring plate. The spring guide shaft and the piston are formed integrally with one another, and the high-pressure spring plate is mounted at one end of the spring guide shaft. The low-pressure spring cover and the high-pressure spring plate form stops that prevent the elastic limit of the respective springs from being exceeded.

[0011] DE 10 2013 009 637 A1 discloses a spring support for a motor vehicle for placement between a coil spring and a spring plate. The spring support comprises a base body made of elastic polymer and a sacrificial anode arranged thereon on the spring side, which in turn is supported by an insert made of solid material intended to prevent the sacrificial anode from breaking under mechanical stress. One embodiment shows a spring support with a circular section arranged between the spring plate and the coil spring, as well as an adjoining cylindrical section that rests against the inside of the spring.

[0012] EP 2 172 352 B1 discloses a spring base for a suspension spring of a wheel suspension. The spring base comprises a piezo actuator embedded between an upper and lower part of the spring base. The piezo actuator can be energized via appropriate connections to specifically compensate for vibrations caused by the spring, or the electrical energy generated in the piezo actuator during vibrations can be fed into the vehicle's electrical system.

[0013] KR 2012 0 061 624 A shows a spring base comprising a circular ring-like section and an internally adjoining cylindrical section. A coil is formed in the surface of the former section, which is intended for the attachment of a coil spring. The cylindrical section has a central recess through which a shock absorber arranged within the coil spring is guided when installed.

[0014] KR 2013 0 017 156 A discloses a spring support with a groove-shaped recess designed to accommodate the end of a coil spring. To ensure improved contact with the coil spring, the partially circular spring support is spirally formed, so that the recess also has a profile that rises along the circumferential direction.

[0015] KR 2015 0 054 378 A shows a motor vehicle suspension in which a coil spring is supported on a spring seat via a spring base. The spring base has a plate-shaped base and a central protrusion extending from it, which is located within the coil spring. Here, securing clips secure the position of an end turn of the coil spring to the spring base. The securing clips enclose the spring wire in a ring-like manner and are detachably attached to the spring base.

[0016] In view of the state of the art shown, there is still room for improvement in the damping of vibrations transmitted between a spring and a spring seat, in particular from a suspension spring to the vehicle body.

[0017] The invention is based on the object of enabling improved vibration damping at the transition between a spring and a spring seat.

[0018] According to the invention, the object is achieved by a spring assembly having the features of claim 1.

[0019] A spring arrangement for a motor vehicle is shown, with a helical spring extending along an extension axis and a rubber-elastic spring base for indirectly supporting the helical spring on a spring seat, wherein at least one intermediate element is arranged between the helical spring and the spring base, which on the one hand rests on the helical spring and on the other hand, in the load-free state, rests on the spring base with a radially extending first contact area, wherein the intermediate element rests on the helical spring with a radially extending second contact area.According to the invention, the intermediate element has a base section and two claw-like flange sections projecting therefrom and a recess located therebetween, which is smaller in dimension than a spring wire of the helical spring to be received therein, wherein surfaces of the intermediate element adjacent to the recess form the second contact area, which bears radially from the inside and from the outside with its claw-like flange sections enclosing the spring wire under pretension against the spring wire and wherein rounded areas are arranged laterally of the first, flat contact area, and wherein at least one reinforcing element is embedded in the intermediate element and enclosed by it.

[0020] The subclaims relate to advantageous embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0021] The invention provides a spring arrangement for a motor vehicle. Suitable motor vehicles are, in particular, cars or trucks. The spring arrangement has a coil spring extending along an axis of extension and a rubber-elastic spring base for indirectly supporting the coil spring on a spring seat. The coil spring can consist in particular of spring steel, but possibly also of another material, e.g. fiber-reinforced plastic or a composite material. The axis of extension corresponds to the direction of extension of the coil spring and can, if necessary, coincide with an axis of symmetry or spring centerline of the coil spring. However, the coil spring does not have to be symmetrical. The axis of extension defines a coordinate system with axial, tangential and radial directions.The coil spring is intended to be supported primarily in the axial direction on the spring seat. The spring arrangement is normally part of a motor vehicle's wheel suspension. The spring connects an unsprung mass of the vehicle with a sprung mass of the vehicle. In any case, the areas on the sprung or unsprung components on which the spring is supported are referred to in this context as the "spring seat." Otherwise, the term is not to be interpreted in a restrictive manner with regard to its shape. Overall, in this sense, a spring seat must be provided for each end of the spring. This could, for example, be a spring plate.

[0022] The design is such that the coil spring is not supported directly on such a spring seat, but indirectly, via the rubber-elastic spring base. As explained below, this does not mean that the coil spring is in direct contact with the spring base. However, at least the spring base is interposed between the coil spring and the spring seat. The spring base is rubber-elastic, meaning it consists at least predominantly of rubber or a comparable material such as an elastomer, silicone rubber, or similar.

[0023] As mentioned above, at least one intermediate element is arranged between the coil spring and the spring base, which intermediate element rests on the coil spring on the one hand and, in the unloaded state, rests on the spring base with a radially extending first contact area on the other. When the spring arrangement is used as intended, the coil spring is supported on the spring base via the intermediate element, so that a flow of force runs from the coil spring via the intermediate element to the spring base (and from there to the spring seat). To ensure this flow of force, the intermediate element rests on the coil spring on the one hand and on the spring base on the other. The first contact area, which extends radially, is provided opposite the spring base. I.e.In contrast to a spring resting directly on the spring base, which has a linear support area and, viewed radially, rests at specific points, the intermediate element rests on the spring base at a plurality of (possibly connected) points along the radial direction. It is understood that, for stability reasons, there must also be a plurality of points or a connected area along the tangential direction at which the at least one intermediate element rests on the spring base.

[0024] There may be a single, continuous first contact area, or it may be subdivided, or several first contact areas may be provided. The statement that the intermediate element rests against the spring base with the first contact area refers to a load-free state, in which the spring arrangement is not under pressure, and the spring base is therefore not elastically deformed. This means that in the unloaded state, the intermediate element rests against the spring base with the radially extending first contact area. This is achieved in that the at least one first contact area has a shape that corresponds to the opposite surface of the spring base, i.e. is complementary to it to a certain extent. However, the contact area does not have to be an exact negative form of the opposite surface, but rather, for example, there may be two or more first contact areas within the first contact area orRecesses or interruptions should be provided between the first contact areas where the surface of the intermediate element recedes from the spring base and thus does not rest against it (at least in the unloaded state). It goes without saying that the intermediate element generally rests against the spring base, at least with its first contact area, even when loaded.

[0025] The invention is based on the finding that strong local compressive loads on the spring base can severely impair its damping properties. If, as is common in the prior art, the coil spring rests directly on the spring base, the unloaded contact area is a linear one that is limited to a single point in the radial direction. This means that the compressive force exerted by the spring is concentrated on a very small area, which in turn leads to high pressure and strong local deformation of the spring base. In particular, the localized high pressure means that vibrations or sound (where the two terms are treated as synonymous below) cannot be effectively dampened, at least in certain frequency ranges. Strong local compressive loads can also lead to premature material fatigue of the spring base.These disadvantages can be avoided by radially distributing the force through the first contact area, resulting in effective pressure limitation. This improves the NVH properties of the spring arrangement and, for example, effectively suppresses the transmission of vibrations generated by the chassis via the coil spring toward a vehicle body on which the spring seat is formed. This is supported not only by the design and the pressure distribution, but also by the mere interposition of the intermediate element, since every boundary layer or material transition is known to impede the propagation of sound waves. Furthermore, the improved pressure distribution results in lower local stress on the spring base, which has a positive effect on its service life.It should be noted that this lower load does not occur at the expense of the intermediate element, since the spring base applies a corresponding pressure distribution based on the counterforces.

[0026] As mentioned above, the intermediate element rests against the coil spring with a radially extending second contact area. With respect to the cross-section in the axial-radial plane, there is no point loading of the intermediate element; instead, the load, i.e. the force acting on the coil spring, is distributed radially, resulting in lower pressure. This can have a positive impact on the service life of the intermediate element. It is also easier to distribute the force acting on the coil spring over the surface of the first contact area if the force is already introduced into the intermediate element via the second contact area in the manner described.Otherwise, there would be a risk that a local load on the intermediate element by the coil spring could lead to an (elastic or plastic) deformation of the intermediate element and a significantly inhomogeneous pressure distribution in the area of ​​the first contact section.

[0027] Particularly preferably, the spring base is provided for support on a vehicle-mounted spring seat. Such a vehicle-mounted spring seat is formed on a vehicle body (body or chassis), while an opposite, wheel-mounted spring seat can be formed on a wheel carrier or control arm. The advantages of the invention are particularly evident in a vehicle-mounted spring seat, since it is crucial to reduce the transmission of vibrations from the spring to the spring seat as much as possible to prevent them from becoming audible and / or noticeable to the occupants.

[0028] Preferably, the coil spring is physically isolated from the spring base. This means that, when the spring assembly is properly assembled, there is no direct physical contact between the coil spring and the spring base. This also precludes direct transmission of vibrations from the coil spring to the spring base. This means that the coil spring is only in contact with the spring base via the intermediate element. Vibration transmission could at best occur via the intermediate element or via the air, although the latter is negligible from an NVH perspective.

[0029] As already explained, the key ideas of the invention are, on the one hand, the interposition of an additional element between the coil spring and the spring base in order to generally impede sound transmission, and on the other hand, the distribution of the pressure acting on the spring base. The latter can be particularly well achieved if the intermediate element has greater rigidity than the spring base. In this case, it is conceivable that the intermediate element is made at least partially of metal or ceramic. Preferably, the intermediate element is made at least partially or at least predominantly of plastic. Plastics, e.g. thermoplastics, can be easily formed into any desired shape and contribute only insignificantly to weight and material costs. In this context, it is expressly possible for the intermediate element to have a composite structure and thus consist of several materials, only some of which have the aforementioned greater rigidity.For example, a plastic could be reinforced with fibers, such as glass fibers, aramid fibers, or carbon fibers. Since sound transmission between bodies with different stiffnesses is usually worse than between bodies with the same stiffness, an improvement in this regard is also achieved if the intermediate element is stiffer than the spring base.

[0030] In principle, it is possible for the coil spring to rest against the intermediate element, with the relative position of the two being secured only by spring tension and frictional forces. In order to better secure the relative position during operation and to facilitate assembly of the spring arrangement, it is preferred, however, for the intermediate element to be attached to the coil spring. This can be achieved in a variety of ways, using a wide variety of detachable or non-detachable connections. One possibility here would be a material-to-material connection, for example by gluing. This can be advantageous in that the adhesive layer leads to the formation of an additional boundary layer, which in turn impedes the transmission of sound and vibrations.On the other hand, it must be taken into account that an adhesive bond must withstand the static and dynamic loads in the connection area between the coil spring and the intermediate element without premature fatigue.

[0031] The intermediate element is preferably connected to the coil spring in a form-fitting and / or force-fitting manner. It can be pushed, clipped, or clamped onto the coil spring, for example. Elastic claws or the like can be formed on the intermediate element, which engage around part of the coil spring and are possibly under tension when fastened, resulting in increased static friction between the intermediate element and the coil spring. In general, the intermediate element can be elastic and have a recess with an inner dimension that is slightly smaller than the corresponding outer dimension of the coil spring, so that when the coil spring is connected to the intermediate element, the latter undergoes elastic deformation, resulting in the intermediate element being preloaded against the coil spring.

[0032] The second contact area rests radially on the inside and outside of the coil spring. This allows the position of the coil spring relative to the intermediate element to be better secured. In particular, this allows for effective attachment of the intermediate element to the coil spring. The radially inner and outer parts of the second contact area form elastic claws or flanges that rest against the coil spring under preload. This design, in which the coil spring is, so to speak, enclosed on both sides by the second contact area, also allows for reliable physical insulation of the coil spring from the spring base.

[0033] As already mentioned above, at least one reinforcing element is embedded in the intermediate element. Said reinforcing element is at least predominantly enclosed by the intermediate element. Typically, it does not form part of the surface of the intermediate element. The reinforcing element serves to structurally reinforce the intermediate element and therefore normally has greater rigidity than other parts of the intermediate element. For example, the intermediate element can consist predominantly of plastic, while a reinforcing element, which may be made of metal or ceramic, for example, is cast into the plastic. In a broader sense, glass fibers, aramid fibers, or carbon fibers, which are enclosed in a plastic matrix for reinforcement, can also be considered reinforcing elements in this sense.

[0034] According to one embodiment, the first contact area is at least partially flat. The plane in which it extends can in particular run perpendicular to the axis of extension, i.e. coincide with the radial-tangential plane. In any case, the surface of the spring base opposite the first contact area is also flat, which corresponds to a particularly simple design. This is in contrast to prior art solutions in which the surface of a rubber-elastic spring base itself is adapted to the shape of the spring. In terms of planning and production, it is often easier to provide an appropriately shaped intermediate element than to adapt the shape of the spring base. With a flat contact area, a particularly even pressure distribution can normally be achieved.

[0035] In principle, an improvement over the prior art can be achieved even if the first contact area has only a very small radial extent, but is not linear. In order to achieve effective pressure distribution, however, a radial extent of the first contact area advantageously corresponds to at least 50% of the thickness of a spring wire of the coil spring. The spring wire is of course the wire from which the coil spring is wound, whereby the term here also refers in a broader sense to coil springs that are not made of metal but, for example, of fiber-reinforced plastic. If the wire has a non-circular cross-section, this refers to the thickness of the wire in the radial direction. More preferably, the radial extent corresponds to at least 75%, at least 100% or at least 150% of the thickness of the spring wire.

[0036] In order to fulfill its inventive function, it is sufficient if the intermediate element is arranged essentially in a region which is located in the axial direction between the spring wire (or the last turn thereof) and the spring base. Accordingly, the intermediate element is preferably designed in the shape of a circular ring. This design of the intermediate element saves material and weight. It does not have to extend over a full circle, but it is preferred that it extends tangentially over at least 180°. In this case, it is preferred that the first contact region also extends tangentially over at least 180°. Larger extensions, e.g. over at least 270°, are also conceivable for both the intermediate element and the first contact region.

[0037] Rounded areas advantageously adjoin the sides of the first contact area. This means that the first contact area is not limited by sharp edges, but rather provides a smooth transition, for example, to the side surfaces of the intermediate element. Sharp edges could lead to very different loads in adjacent areas of the spring base if the intermediate element deforms the spring base, which in turn could cause damage or premature fatigue of the spring base. Such edges could, in a sense, "cut" into the spring base. Depending on the direction of the force applied, particularly high pressures could also occur in the area of ​​the edge, which, however, are precisely what the invention aims to avoid.

[0038] Further advantageous details and effects of the invention are explained in more detail below with reference to an exemplary embodiment illustrated in the figures. They show: Fig. 1 is a schematic sectional view of a front view of a spring arrangement according to the invention within a wheel suspension; Fig. 2 a bottom view of part of the spring arrangement from Fig. 1; Fig. 3 a sectional view along the line III-III in Fig. 2; and Fig. 4 a Fig. 3 corresponding sectional view of a spring arrangement according to the prior art.

[0039] In the different figures, identical parts are always provided with the same reference symbols, which is why they are usually only described once.

[0040] Fig. 1 shows a schematic side view of a spring arrangement 1 according to the invention, which is part of a wheel suspension 20 of a motor vehicle. A wheel 21 is rotatably mounted on a wheel carrier 22, which in turn is pivotally connected to a vehicle body 25 via two wishbones 23, 24. A lower spring plate 10 is arranged on a control arm 24, while an upper spring plate 11 is arranged on the vehicle body 25. The aforementioned spring plates 10, 11 form spring seats for a coil spring 2, by means of which the vehicle body 25 is sprung relative to the wheel 21, the wheel carrier 22, and the control arms 23, 24. In the present case, the coil spring 2 is made of spring steel; alternatively, however, a coil spring made of fiber-reinforced plastic, for example, could also be used. The coil spring 2 extends along an extension axis A, which defines an axial direction and thus also a radial and tangential direction.It is understood that the wheel suspension 20 normally also includes a shock absorber, which is not shown here for the sake of simplicity.

[0041] The coil spring 2 is supported indirectly on the two spring plates 10, 11. In the case of the upper spring plate 11, a first spring pad 3 made of rubber is interposed, which rests against the spring plate 11. However, the coil spring 2 is not supported directly on the first spring pad 3, but rather via an intermediate element 4 arranged therebetween, which will be discussed in more detail below. The coil spring 2 is supported on the lower spring plate 10 via a second spring pad 5, also made of rubber. The spring plates 10, 11 and the spring pads 3, 5 can, if necessary, be of similar design. It is understood that the design shown is purely exemplary. For example, a different type or number of links could be used, or the lower spring plate 10 could be supported directly on the wheel carrier 22.It would also be conceivable to provide an intermediate element between the coil spring 2 and the second spring base 5.

[0042] Fig. Figure 2 shows a bottom view of a part of the spring arrangement 1, wherein the drawing plane corresponds to the radial-tangential plane, perpendicular to the extension axis A. It can be seen that an end turn 2.1 of the helical spring 2 is accommodated within the intermediate element 4, which is shaped like a circular arc and extends over an arc of approximately 300°. Depending on whether the end turn 2.1 runs parallel to the drawing plane or rises relative to it, the intermediate element can be flat or can rise in a ramp-like or helical manner. In any case, the embodiment shown provides that a Fig. 2 rear side of the intermediate element 4 facing the spring base 3 runs parallel to the plane of the drawing.

[0043] The further design of the intermediate element 4 is shown in the sectional drawing in Fig. 3, which corresponds to a section along the line III-III in Fig. 2. It should be noted that the Fig. 3 upper part related to Fig. 1 is at the bottom and vice versa. The intermediate element 4 is predominantly made of thermoplastic and has a base section 4.1 as well as two claw-like flange sections 4.2, 4.3 projecting therefrom. On the side of the base section 4.1 facing the spring base 3, a first contact area 4.4 is formed, which extends on the one hand along a tangential direction T circumferentially along the entire intermediate element 4, and on the other hand along a radial direction R along a distance which, in the present case, corresponds approximately to 150% of the thickness of a spring wire 2.2 of the end turn 2.1. The first contact area 4.4 is flat and thus corresponds to a flat surface 3.1 of the spring base 3.

[0044] The flange sections 4.2, 4.3 surround the spring wire 2.2 and are arranged radially inside and outside thereof. Due to the elasticity of the plastic from which the intermediate element 4 is formed, the spring wire 2.2 can be inserted into a recess 4.5 located therebetween by bending the flange sections 4.2, 4.3. When the spring wire 2.2 reaches the Fig. 3, the flange sections 4.2, 4.3 spring back, although they do not reach their original position because the recess 4.5 is slightly smaller than the spring wire 2.2. Thus, the flange sections 4.2, 4.3 are preloaded against the spring wire 2.2. Therefore, a both force-locking and form-locking connection is established between the intermediate element 4 and the coil spring 2.

[0045] The surfaces of the intermediate element 4 adjacent to the recess 4.5 form a second contact area 4.6, which extends in the axial direction but also in the radial direction R. The latter is particularly important in that it distributes the forces acting on the intermediate element 4 by the helical spring 2 over a large area, thereby structurally relieving the intermediate element 4 as a whole. Fig. 3, this is illustrated by the pressure distribution p sketched below the first contact area 4.4. While the position of the intermediate element 4 shown relative to the spring base 3 corresponds to an unloaded or load-free state in which the coil spring 2 exerts no pressure, the pressure distribution p shown corresponds to a loaded state. In this case, the intermediate element 4 would naturally be pressed into the surface 3.1 of the spring base 3, although this deformation would remain rather minor due to the uniform pressure distribution p. In order to avoid stresses caused by strong local pressure differences in the edge areas of the first contact area 4.4, rounded areas 4.7, 4.8 are provided on the sides thereof, resulting in a lower load on the spring base 3 than if comparatively sharp edges were present there. Under certain circumstances, it is sufficient for the intermediate element 4 to be made entirely of plastic.Optionally, however, as in . Fig. As shown in Figure 3, a reinforcing element 6, e.g., made of metal or ceramic, can be embedded in the plastic matrix. This stabilizes the intermediate element 4 as a whole, which can increase its service life and better ensure even force distribution.

[0046] The advantages of the inventive concept are compared with Fig. 4, which shows a configuration without intermediate element 4. Here, the spring wire 2.2 lies directly on the spring base 3, which in the unloaded state corresponds to a contact area that is limited to a point along the radial direction R. In the Fig. In the loaded state illustrated in Figure 4, the spring wire 2.2 deforms the surface 3.1 of the spring base 3 comparatively strongly, which corresponds to a locally limited pressure distribution p with relatively high pressures. This locally limited, strong load can lead to premature material fatigue of the spring base 3. More importantly, however, is that such a pressure distribution leads to the spring base 3 not being able to effectively dampen certain vibrations emanating from the coil spring 2, but rather transmitting them to a greater extent. With a more even pressure distribution as in Fig. As shown in Figure 3, such transmission of vibrations is largely suppressed. Furthermore, the interposition of the intermediate element 4 creates an additional interface, whereby some of the vibrations or sound waves are not transmitted but reflected. List of reference symbols: 1 spring arrangement 2 coil springs 2.1 Final turn 2.2 Spring wire 3 spring pads 3.1 Surface 4 Intermediate element 4.1 Basic section 4.2, 4.3 Flange section 4.4 first investment area 4.5 Recess 4.6 second investment area 4.7, 4.8 rounded area 5 spring pad 6 Reinforcing element 10, 11 spring plate 20 Wheel suspension 21 wheels 22 wheel carriers 23, 24 wishbones 25 Vehicle body A extension axis p pressure distribution R radial direction T tangential direction

Claims

[1] Spring arrangement (1) for a motor vehicle, comprising a helical spring (2) extending along an extension axis (A) and a rubber-elastic spring base (3, 5) for indirectly supporting the helical spring (2) on a spring seat (10, 11), wherein at least one intermediate element (4) is arranged between the helical spring (2) and the spring base (3, 5), which on the one hand bears against the helical spring (2) and on the other hand, in the load-free state, bears against the spring base (3, 5) with a radially extending first bearing region (4.4), wherein the intermediate element (4) bears against the helical spring (2) with a radially extending second bearing region (4.6), characterized byin that the intermediate element (4) has a base section (4.1) and two claw-like flange sections (4.2, 4.3) projecting therefrom and a recess (4.5) located therebetween, which is smaller in dimension than a spring wire (2.2) of the helical spring (2) to be received therein, wherein surfaces of the intermediate element (4) adjacent to the recess (4.5) form the second contact area (4.6) which bears radially from the inside and from the outside with its claw-like flange sections (4.2, 4.3) encompassing the spring wire (2.2) under pretension, and wherein rounded areas (4.7, 4.8) are arranged laterally of the first, flat contact area (4.4), and wherein at least one reinforcing element (6) is embedded in the intermediate element (4) and enclosed by it. [2] Spring arrangement (1) according to claim 1, characterized by that the coil spring (2) is physically isolated from the spring base (3, 5). [3] Spring arrangement (1) according to one of claims 1 or 2, characterized by that the intermediate element (4) has a greater rigidity than the spring base (3, 5). [4] Spring arrangement (1) according to one of the preceding claims, characterized by that a radial extension of the first contact area (4.4) corresponds to at least 50% of a thickness of a spring wire (2.2) of the helical spring (2). [5] Spring arrangement (1) according to one of the preceding claims, characterized by that the intermediate element (4) is circular in shape and extends tangentially over at least 180°.

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