Motor vehicle leaf spring assembly

A leaf spring assembly resiliently supporting a wheel carrier on a vehicle body of a motor vehicle. The leaf spring assembly including first and second spring leaves and a clamp having a clamping part exerting a clamping force whereby the first and second spring leaves are held together by the clamp. A bridging part arranged between the first spring leaf and the clamping part transmits at least part of the clamping force from the clamping part to the first spring leaf bridging the second spring leaf and reducing the clamping force exerted thereon.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a leaf spring assembly for a motor vehicle wheel suspension; and more specifically to a leaf spring assembly including two spring leaves for resiliently supporting a wheel carrier on a vehicle body.

2. Description of Related Art

Leaf spring assemblies that resiliently support a wheel carrier on a motor vehicle are generally known in the art. A wheel carrier includes any device creating a mechanical connection between a vehicle wheel held by the wheel carrier and the wheel suspension of the motor vehicle. Leaf spring assemblies are used in commercial vehicles, for example smaller and larger trucks. The leaf springs are usually attached to the motor vehicle oriented in such a manner that their longitudinal extension runs substantially parallel to a longitudinal direction of the motor vehicle.

As is generally known, a leaf assembly may include a plurality of spring leaves formed of a metal material and/or a fiber composite material. In the suspension section of the leaf spring, the wheel carrier is usually connected to the leaf spring assembly via a fastening mechanism, wherein the fastening mechanism couples all the spring leaves of the leaf spring assembly together, pressing them one against another. Besides being used for fastening the wheel carrier to the leaf spring, the fastening mechanism also clamps the individual spring leaves to one another and is therefore also referred to herein as clamp.

SUMMARY OF THE INVENTION

A wheel suspension for a motor vehicle including a leaf spring having a suspension section including a first spring leaf and a second spring leaf. A clamp holds the first spring leaf and second spring leaf adjacent one another. The clamp including a clamp plate adjacent the second spring leaf. A bridging part extends between the first spring leaf and the clamp plate. The bridging part extending forming a force transmission path that bypasses the second spring leaf and transmits at least a portion of the clamping force directly from the clamp plate to the first spring leaf reducing the clamping force on the second spring leaf.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Parts that are comparable in terms of their function are always provided with the same reference numbers in the different figures, meaning these are usually also only described once.

FIG. 1is a schematic side view of an exemplary embodiment of a leaf spring assembly1for a wheel suspension of a motor vehicle. The leaf spring assembly1attached to the motor vehicle with its longitudinal axis L extending substantially parallel to the longitudinal direction of the motor vehicle.

FIG. 1shows a leaf spring assembly1on one side of the vehicle. The motor vehicle includes another leaf spring assembly1on the opposite side of the vehicle, wherein the leaf spring assembly1inFIG. 1is on both sides of the vehicle.

The leaf spring assembly1includes a leaf spring2resiliently supporting a wheel carrier (not shown) on a vehicle body3of the motor vehicle, depicted schematically inFIG. 1. A rigid axle4holds the wheel carrier in the exemplary embodiment, wherein the rigid axle4and the wheel carrier, are connected to the leaf spring2.

The leaf spring2has a first end section5with a first fastener6fastening the leaf spring2to the vehicle body3, a longitudinally opposite second end section7with a second fastener8fastening the leaf spring2to the vehicle body3, and a suspension section9extending between the two end sections5,7. A clamp10fastens the wheel carrier, in this case the rigid axle4holding or supporting the at least one wheel carrier, to the leaf spring2. The rigid axle4can be connected to the clamp10through different connection methods, for example welding, screwing, riveting, and adhesion. Connection methods for fastening the rigid axle4to the clamp10are known in the art and are not further described.

The leaf spring2has two spring leaves11,12. The spring leaf11is also called the first or upper spring leaf and the spring leaf12as the second or lower spring leaf. In the exemplary embodiment depicted inFIG. 1, the first or upper spring leaf11is made of a metal material, for example steel, and the second lower spring leaf12is made of a fiber composite material.

The fiber composite spring leaf12of the leaf spring assembly1may also be called the supporting spring leaf or auxiliary spring leaf. Its main purpose is to support the metal spring leaf11. The support provided gradually or progressively as the load on the leaf spring2increases, since the fiber composite spring leaf12, unlike the metal spring leaf11, is substantially straight in design, so the free ends13of the supporting spring leaf12are spaced furthest from the metal spring leaf11over the entire course of the longitudinal extension L of the fiber composite spring leaf12when the metal spring leaf11is in the unloaded state.

The first spring leaf11need not necessarily be made of a metal material, but may be a fiber composite spring leaf. Besides the first upper spring leaf11, there may be additional upper leaf springs (not shown) configured in a similar manner to the first spring leaf11, which are operatively connected to the spring leaf11. The additional upper spring leaf/spring leaves not shown here is/are preferably made of the same material as the first spring leaf11. It is unnecessary that the second lower spring leaf12be made of a fiber composite material, it could be made of a metal material, for example steel. The leaf spring assembly includes a leaf spring2having a first upper spring leaf11made of a metal material and a second lower spring leaf12made of a fiber composite material. The unloading of the fiber composite spring leaf12is advantageous, however, as the fiber composite spring leaf12reacts considerably more sensitively to high clamping forces introduced by the clamp10to the spring leaves11,12, particularly in the region of the claim10the leaf spring2opposite the metal spring leaf11. A traditional embodiment of a leaf spring assembly known from the prior art can under certain circumstances be damaged by these. An overload damaging the fiber composite spring leaf12is safely prevented by the present invention, as set out in greater detail below.

The free ends13of the support spring leaf12contact the upper spring leaf11only when a large load is applied to it. To dampen this action, the supporting spring leaf12has, in the region of its free ends13, rubber buffers14arranged between the first and second spring leaf11,12. The lower leaf spring12prevents overloading of the upper spring leaf11.

FIG. 1shows the leaf spring2of the leaf spring assembly1having two spring leaves11,12, at least in its suspension section9. These are held pressed against one another by the clamp10. The clamp10of the exemplary leaf spring assembly1has two substantially U-shaped bolts15, or U-bolts, spaced apart from one another in the longitudinal direction L of the leaf spring. The U-bolts15enclose the two spring leaves11,12on three sides, seeFIG. 3. The leaf spring assembly1is shown on the upper side of the first spring leaf11facing away from the second spring leaf12and also along the two side surfaces of the spring leaves11,12. The lower open sides of the U-shaped bolts15are each closed by a lower clamping plate17secured by threaded nuts16on the free ends of the U-shaped bolt15. The clamping plate17lying adjacent to an underside of the second spring leaf12. In the exemplary embodiment the leaf spring assembly1, the clamp10contains an upper clamping plate18inserted between the upper side of the first spring leaf11and the respective U-bolt15. The clamp10exerts a clamping force F through the respective clamping parts15,16,17, and18both in a first active direction on the first spring leaf11and in a second active force substantially opposite the first clamping force on the second spring leaf12. The extent of the total clamping force F exerted by the clamp10on the leaf spring2is determined in a known manner by correspondingly tightening the threaded nuts16.

FIG. 2shows a detailed sectional view of the suspension section9of the leaf spring assembly1including the clamp10.FIG. 3depicts a cross-sectional view of the leaf spring assembly1fromFIG. 1along the sectional line A-A inFIG. 2in the transverse extensional direction Q of the leaf spring assembly1.

FIGS. 2 and 3show a plurality of bridging parts19arranged and configured between the first spring leaf11and the lower clamping plate17of the clamp10to absorb at least part of the clamping force F acting between the first spring leaf11and the clamping part17and transmit it between the spring leaf11and the clamping part17. The proportion of the clamping force F absorbed and transmitted by the bridging parts19in each case is denoted inFIGS. 2 and 3using the reference number F″. Following the removal of all clamping force proportions F″ received by the bridging parts19, a residual force proportion F′, transmitted between the first and second spring leaf11and12, remains of the total clamping force F. This residual force proportion F′ may be zero when the total of all clamping force proportions F″ absorbed by the bridging parts19corresponds to the total clamping force F exerted by the clamp10on the leaf spring2. In each case, the absorption of the clamping force proportions F″ by the bridging parts19leads to a reduction in the residual clamping force F′ transmitted between the first and second leaf spring11,12with a leaf spring assembly1as depicted inFIGS. 1 to 3with a leaf spring2composed of at least one metal spring leaf11and a composite spring leaf12. Preferably, the residual clamping force F′ is at most half as great as the total clamping force F, so the composite spring leaf12is adequately unloaded and therefore protected from a damaging overload.

In addition, the bridging parts19bridge the second spring leaf12in a force-free manner, they are not connected to the second-spring leaf12in a force-fitting, substance-bonded or form-fitting manner in relation to the force transmission direction of the clamping force proportions F″ defined by them. With the exemplary embodiment of the leaf spring assembly1shown, the bridging parts19are columnar in design, taking the form of cylinders, for example. The force-free bridging of the second spring leaf12includes the second leaf spring12having through bores or openings20, seeFIG. 4, with correspondingly configured diameters, wherein the respective bridging parts19extend through the openings20in a substantially force-free manner.

Although the bridging parts19are not connected to the second spring leaf12in a force-fitting, substance-bonded or form-fitting manner in relation to their force transmission direction of the clamping force proportions F″, the bridging parts19most likely create a form fit for the spring leaves11and12in relation to the longitudinal direction L and the lateral direction Q of the spring leaves11,12to reduce or prevent relative movement between them. Wherein wear, for example abrasion between the spring leaves11,12resulting from relative movement is effectively prevented, particularly on their contact surfaces.

FIGS. 2 and 3an exemplary embodiment including a planar intermediate layer21,22inserted between the first spring leaf11and the second spring leaf12and between the second spring leaf12and the third clamping part17of the clamp10. The intermediate layers21,22are not required. These intermediate layers21and22may be made of a metal material, a rubber-elastic material and/or a dimensionally stable plastic. They may, in addition, be multi-layer in design, so that, for example, the intermediate layer21has a metal layer on its side facing the metal spring leaf21and a rubber-elastic layer or a dimensionally stable plastic layer on its side facing the fiber composite spring leaf12. Likewise, the intermediate layer22may, for example, have a rubber-elastic layer or a dimensionally stable plastics layer on its side facing the fiber composite spring leaf12and a metal layer on its side facing the clamping part17, particularly when the clamping part17is also made of a metal material. An embodiment of the intermediate layers21and22may be formed by two separate intermediate layers, one made of a metal material, the other of a rubber-elastic material or a dimensionally stable plastic in each case and two separate intermediate layers, one made of a metal material, the other of a rubber-elastic material or a dimensionally stable plastic. An intermediate layer adjacent to the fiber composite spring leaf12, for example the intermediate layers21and22, may, for example, be directly incorporated in the fiber composite spring leaf12, for example vulcanized or inserted in a corresponding production form during the manufacturing process of the fiber composite spring leaf12and in this way incorporated in the fiber composite spring leaf12.

FIGS. 4a, 4b, 4c, 4dand 4edepict five plan views of a contact surface23of different second spring leaves12,24,25,26,27in each case, according to further exemplary embodiments of a leaf spring assembly (not shown in its entirety here) according to the invention. A first spring leaf, for example, the spring leaf11in the leaf spring assembly1, lies adjacent to the contact surface23shown of every second spring leaf in the manner described or is clamped against the second spring leaf12,24,25,26,27in each case by a clamp, for example the clamp10inFIG. 1. A respective position and course of the two U-bolts15of the clamp10inFIGS. 1-3is indicated for example inFIG. 4by a corresponding dotted line15a.

FIG. 4bshows a plan view of the second spring leaf12as described above. The other second spring leaves24,25,26and27depicted inFIG. 4are also produced from a fiber composite material.

FIGS. 4a-4eshow both the number, position, and shape, including the cross-sectional shape, of the bridging parts19,28,29,30and31may be different. All bridging parts28,29,30and31inFIGS. 4a, 4c-4eare columnar in design, as with the bridging part19,FIG. 4balready described above. As has mentioned earlier, the bridging parts, for example the bridging parts19,28,29,30and31shown here, need not necessarily have a constant diameter over their columnar longitudinal extension, but they may also have at least one narrowing and/or at least one thickening.

InFIG. 4athree substantially identical, cylindrical bridging parts28are arranged linearly along the central longitudinal axis of the second spring leaf24running parallel to the longitudinal extension direction L. The bridging parts28have a larger diameter than, for example, the four cylindrical bridging parts19arranged in a rectangle inFIG. 4bof the leaf spring assembly1depicted inFIGS. 1 to 3andFIG. 4b.

FIG. 4cshows two bridging parts29with an elliptical cross section, each aligned with the major axis of the ellipse extending substantially parallel to the transverse extension direction Q of the spring leaf25.

FIG. 4dshows four bridging parts30likewise with an elliptical cross section, aligned in a rectangle, with the major axis of the ellipse extending substantially parallel to the longitudinal extension direction L of the leaf spring26.

Finally,FIG. 4eshows a linear arrangement of two cruciform bridging parts31and a link-shaped bridging part32arranged between them.

A plurality of other different embodiments and arrangements of bridging parts are also possible and fall within the basic idea underlying the invention.

FIG. 5shows a perspective partial view of another exemplary embodiment of a leaf spring assembly33according to the invention. The partial view depicts the suspension section9of a two-leaf leaf spring arrangement34of the leaf spring assembly33. A first spring leaf35is formed from a metal material, for example steel, and a second spring leaf36from a fiber composite material. The leaf spring assembly33depicted inFIG. 5has two bridging parts37that are columnar in design, as with the bridging parts19,28,29,30,31and32previously described. Bridging parts37, unlike the bridging parts19,28,29,30,31, and32made of a solid material, are hollow inside37a, configured as hollow cylinders, for example, as depicted inFIG. 5.

FIG. 5shows above and below the fiber composite spring leaf36and lying adjacent thereto are planar plastic intermediate layers38, one upper and one lower. A planar metal intermediate layer39is furthermore arranged between the upper plastics intermediate layer38and the underside of the first spring leaf35. A metal plate40is furthermore arranged on the underside of the plastics intermediate layer38arranged on the underside of the fiber composite spring leaf35. This metal plate40forms the first clamping part of a clamp41which contains, a clamping plate42lying adjacent to the upper side of the metal spring leaf35as a second clamping part, two straight threaded bolts43each with a bolt head44as the third clamping parts, and threaded nuts45that can be screwed onto the respective end opposite the bolt heads44as the fourth clamping parts.

The bolts43of the clamp41are guided through the hollow cavity37aof the bridging parts37in each case. This embodiment allows a compact design of the leaf spring assembly33, as at least part of the clamp41runs inside the two spring leaves35,36. The two bridging parts37are guided in a force-free manner through corresponding through-openings36ain the second spring leaf36, as described for the leaf spring assembly1inFIGS. 1 to 3. In addition, they lie on the underside of the first spring leaf35, on the underside of the metal intermediate layer39, the upper side of the metal plate40acting as the first clamping part, or on the bolt heads43acting as the third clamping parts, so the total clamping force F exerted by the fastening clamping means41on the leaf spring34is partially guided via the bridging parts37arranged between the first spring leaf35and the first clamping part40or the third clamping parts44of the fastening clamping means41in a force-transmitting manner, as has been described above in relation to the leaf spring assembly1.

Because the bridging parts37are directly adjacent to the metal intermediate layer39, for example with their ends facing the first spring leaf35, they bring a uniform clamping force distribution over the individual bridging points37. Here, the metal intermediate layer39may also be referred to as the pressure plate. In the same way, the metal layer40may also act as a pressure plate for a uniform clamping force distribution on the individual bridging parts37of the bolt heads44, if these lie adjacent to the metal layer40with their ends facing the bolt heads44.

The bridging parts37may also be connected to a pressure plate39,40in a substance-bonded or form-fitting manner, so an assembly of the corresponding leaf spring assembly can be realized even more easily and quickly.

The leaf spring assembly1inFIGS. 1 to 3may also be provided with a pressure plate corresponding to the metal intermediate layer39inFIG. 5, like the intermediate layer21depicted inFIG. 2, to which the bridging parts19may be optionally fastened in a substance-bonded or form-fitting manner. The bridging parts19of the leaf spring assembly1may also be fastened to the lower clamping plate17of the clamp10in a substance-bonded or form-fitting manner. Suitable substance-bonding and form-fitting connection methods are, for example, adhesion, welding, screwing, and riveting.

In the embodiment of the leaf spring assembly33inFIG. 5, when the bolts43are sufficiently strong for the loads occurring during operation of the leaf spring assembly33, further fastening mechanisms, other than the clamp41can be dispensed with. The wheel carrier or the rigid axle4,FIG. 1, may be fastened to the metal plate40.

However, should the bolts43not be strong enough to support operation loads of the motor vehicle, the leaf spring assembly33depicted inFIG. 5with the clamp41may be a particularly easy-to-handle assembly arrangement in which the leaf spring assembly33for mounting is held together in a properly aligned manner by the clamp41.

In the case of the previously described exemplary embodiments of the leaf spring assemblies1and33, the clamping force proportion F″ guided via the respective bridging parts19,28,29,30,31,32and37can be selectively determined through the lengths thereof and/or through the thicknesses of the inserted intermediate layers21,22and38and/or through the material properties thereof, in particular their stiffness or elasticity.

In the exemplary embodiment, the leaf spring assembly according is used in a wheel suspension for the resilient support of a wheel carrier, in particular a rigid axle holding or supporting the wheel carrier, on a motor vehicle, for example a commercial vehicle such as a truck.

The leaf spring assembly includes a leaf spring resiliently supporting a wheel carrier on a vehicle body of the motor vehicle. A wheel carrier means any device mechanically connecting a vehicle wheel to the wheel suspension of the motor vehicle, for example, a vehicle axle, such as a rigid axle, to which a wheel carrier on which a vehicle wheel is rotatably mounted is attached. The leaf spring has a first end section, containing a first leaf spring end, a second end section, containing a second leaf spring end, which is diametrically opposite this first end section, and a suspension section extending between two end sections. The leaf spring is attached to the vehicle body at its first leaf spring end by a suitable fastener and attached to the vehicle body at its second leaf spring end by suitable fastener. In contrast to the two end sections, primarily used to fasten the leaf spring to the vehicle body or to an auxiliary frame connected to the vehicle body, the suspension section provides the actual spring action of the leaf spring due to its elastic deflection capability.

In the suspension section of the leaf spring a clamp fastens or attaches the wheel carrier to the leaf spring. The leaf spring of the leaf spring assembly includes two spring leaves, at least in the suspension section, a first spring leaf and a second spring leaf held pressed against one another by the clamp because the clamp exerts a clamping force through a clamp part both in a first effective direction on the first spring leaf and also in a second effective direction substantially opposite the first effective direction on the second spring leaf. The clamp contains at least one clamp part exerting a necessary clamping force on the leaf spring, that is on at least some of the spring leaves forming the leaf spring, directly or also indirectly. The Insertion of an additional clamp part may, for example distribute the clamping force exerted by the first clamp part over a larger area on the spring leaf or spring leaves. Consequently, clamp part means each element of the clamp that introduces or transmits the clamping force produced by the clamp to the leaf spring, to at least some of the spring leaves forming the leaf spring, or to at least one further clamp part.

A bridging part arranged and configured between the first spring leaf and the clamp absorbs at least part of the clamping force acting between the first spring leaf and the clamp and transmits it between them, that is between the first spring leaf and the clamp, wherein it bridges the second spring leaf in a force-free manner.

Without a bridging part, the clamping force is usually introduced by a clamp part of the clamp to the first spring leaf, is substantially transmitted by the first spring leaf to the second spring leaf, and then received again by a clamp part of the clamp, and vice versa. Here, a substantially single force-transmission path is created that is followed by the clamping force, the force-transmission path leading from the clamping part via the first and second spring leaf and back again to the clamping part, and vice versa. The clamping force therefore acts substantially to the full extent both on the first and on the second spring leaf.

The clamp may exhibit a plurality of clamping parts, so the clamping force exerted by a first clamping part on the first spring leaf, for example, can be transmitted via the second spring leaf to a second clamping part different from the first clamping part. The clamp may, however, also have a clamping part enclosing the two spring leaves, for example in a metal or plastic strap that firmly encloses the at least two spring leaves and presses them together. While discussing a clamp or clamping part, a plurality of clamping parts can be supplied as or parts of the clamp, wherein the clamping force can be transmitted between multiple clamping parts; for example, introduction of the clamping force by a clamping part to the spring leaves need not necessarily be returned to the same clamping part.

According one embodiment a force-conveying bridging part between the first spring leaf and a clamping part of the clamp bridges the second spring leaf in a force-free manner, establishing a force-transmission path effective in traditional leaf spring assemblies for guiding the clamping force between the clamping part and the spring leaves pressed together by the clamp that can be advantageously split into a first clamping force path following the traditional force-transmission path from the clamping part via the two spring leaves back to the clamping part, and a second clamping force path leading from the clamping part via the first spring leaf, the at least one bridging part, and back to the clamping part, excluding the second spring leaf bridged in a force-free manner by the bridging part. The clamping force path in the leaf spring assembly is guided between the first spring leaf and the clamping part of clamp in at least two partial force paths running parallel to one another, one of which is guided via the bridging part.

The design and arrangement of the bridging part selectively determines the extent of the clamping force received by the bridging part and therefore passed on to the second spring leaf, unloading to the desired extent the second spring leaf. The nature of the design of the bridging part may include its geometry, shape and the material from which it is made. This and its arrangement between the first spring leaf and the clamping part of the clamp provide force absorption capability and force transmission capacity, also its stiffness and elasticity, can be determined. In this way, the force distribution along the different force-transmission paths described above can be selectively determined. A corresponding embodiment of the bridging part achieves a force-transmission path running via the bridging part to guide wherein substantially exerting the total clamping force of the clamp on the leaf spring, so the second spring leaf is maximally unloaded, in the exemplary example completely unloaded. Other force distributions are likewise achievable.

An unloading of the second spring leaf using the bridging part involves an exceptionally low outlay compared with the production of the total leaf spring assembly and can therefore be achieved simply and cost-effectively. In addition, providing the bridging part allows a simple and compact design of the leaf spring assembly. Its weight, compared with traditional leaf spring assemblies, is not increased substantially or at most slightly by provision of the bridging part.

In accordance and embodiment, the bridging part between the first spring leaf and the clamping part is configured and arranged so it absorbs more than half the clamping force exerted on the leaf springs by the clamp and, the second leaf spring is loaded with less than half this clamping force. The load absorbed by the bridging part can also be called the main load.

A further embodiment includes making the first spring leaf from a metal material and the second spring leaf from a fiber composite material. In this embodiment the unloading of the second leaf spring achieved is advantageous, as the fiber composite spring leaf reacts considerably more sensitively to relatively high clamping forces introduced by the clamp to the spring leaves for a secure fastening of the wheel carrier to the leaf spring, particularly in the region of the clamp to the leaf spring opposite the metal spring leaf, and can under certain circumstances be damaged by these. An overload damaging the fiber composite spring leaf is reliably prevented, the bridging part can be specially configured for the loading capability of the fiber composite spring leaf used in the respective application.

Since the leaf spring has at least two spring leaves, it may also exhibit more than one metal spring leaf and/or more than one fiber composite spring leaf.

The second spring leaf, the fiber composite spring leaf, configured as a supporting spring leaf, also as an additional spring leaf or an auxiliary spring leaf. The supporting spring leaf supports the spring leaf or the other spring leaves, in that it/they is/are additionally supported by the supporting spring leaf with an increasing load or deflection. This support may take effect gradually, for example, as the load on the leaf spring increases. The supporting spring leaf may, for example, be substantially straight in design, so the free ends of the supporting spring leaf are spaced as far apart as possible from the remaining spring leaf or spring leaves when it/they is/are in the unloaded state and only contact it/them when there is a high load. This property provides a progressive characteristic curve of the leaf spring, as the supporting force of the supporting spring leaf increases with the increasing load or deflection of the spring leaf or the other spring leaves. The supporting spring leaf may, however, also be configured substantially to follow the curvature of the spring leaf or the other spring leaves in the unloaded state.

Another embodiment of the invention includes a planar intermediate layer inserted between the first spring leaf and the second spring leaf and/or between the clamping part and the first spring leaf and/or between the second spring leaf and the clamping part. The intermediate layer made of a metal material, a rubber-elastic material and/or a dimensionally stable plastic. The intermediate layer of planar design extending over at least the entire contact surface between the respective adjacent components. An intermediate layer adjacent to a metal spring leaf or a metal clamping part is made of a metal material and forms an intermediate layer made of a rubber-elastic material or a plastic adjacent to a fiber composite spring leaf or a plastic clamping part. The intermediate layer may also include multiple layers, including a metal material on a first side and a rubber-elastic material or a plastic on the opposite second side.

Insertion of an intermediate layer in the intermediate spaces allows in an advantageous, simple manner a thickness adjustment of the assembly made of the two spring leaves enclosed by the clamp, within the clamping part clamping the two spring leaves. In this way, the proportion of the clamping force exerted on the second spring leaf can be selectively changed, as the insertion of an intermediate layer when the clamping part is in an otherwise unchanged position means that closer contact can be established between the second spring leaf and the first spring leaf, because of which the proportion of the clamping force transmitted from the first spring leaf to the second spring leaf is increased. Conversely, by removing an intermediate layer the reverse effect can be achieved. The selection of material for the intermediate layer in each case, its elasticity and stiffness all allow a specific setting in this respect.

The intermediate layer may also be used as tolerance compensation for the assembly made up of at least two spring leaves and the clamp. The intermediate layer, provides for a more uniform load distribution over the entire contact surface of the components lying adjacent to one another across the intermediate layer, which effectively prevents local overloading.

The intermediate layer further prevents penetration of unwanted foreign substances, for example dirt particles, salt, water, and the like, into the respective contact surface occupied by the intermediate layer, preventing or reducing wear of the leaf springs accelerated by these foreign substances, particularly on a spring leaf formed from a fiber composite material.

A further embodiment of the invention, includes the bridging part having a columnar design and extending through a corresponding through-opening in the second spring leaf. The through-opening in the second spring leaf has a diameter sized so the bridging part extends through the second spring leaf in a non-force-fit or form-fit manner wherein the force application direction of the clamping force conducted between the first spring leaf and the clamping part of the clamp. No clamping force absorbed by the bridging part is transmitted to the second spring leaf, corresponding to a force-free passage of the bridging part through the second spring leaf.

The columnar bridging part need not have a constant cross section in its longitudinal extension direction. For example, for the columnar bridging part may have a narrowing or thickening in its columnar profile. Likewise, the columnar bridging part need not have a solid design, it could be hollow or partially hollow in design.

Alignment of a longitudinal axis of the columnar bridging part preferably takes place substantially in a thickness direction of the spring leaves when the leaf spring assembly is in the mounted state on the vehicle, toward a vertical axis of the vehicle. This means the columnar bridging part offers an advantage because the spring leaves cannot be displaced against one another or relative to one another in their longitudinal or lengthwise direction and also in their lateral or crosswise direction, as the columnar bridging part guided through the corresponding through-opening in the second spring leaf and in force-transmitting connection with the first spring leaf and the at least one clamping part of the clamp creates a form fit in relation to the longitudinal and lateral direction of the spring leaves and therefore suppresses the relative movement between them. Wearing, e.g. abrasion, of the spring leaves, particularly on their contact surfaces, caused by a relative movement of this kind is effectively prevented.

The longitudinal or lengthwise direction of the leaf springs or spring leaves is the direction the leaf spring extends from its first end section to the opposite second end section. Correspondingly, the lateral or crosswise direction is a direction running substantially perpendicular to the vibration plane of the leaf spring, wherein the vibration plane through the bending movement of the leaf spring is determined under different load conditions.

The bridging part described above makes it easier to assemble the leaf spring assembly, since the assignment or positioning of the spring leaves in relation to one another and the clamp is already defined by the columnar bridging part. A special assembly device for the alignment of the spring leaves can therefore be dispensed with.

Over the length, extension in its longitudinal direction, of the columnar bridging part, the proportion of the clamping force absorbed and guided by the bridging part from the first spring leaf or clamping part can be defined, as has been described above. In addition, via a corresponding formation of its cross section, influence can also be exerted on the clamping force or load distribution. In this sense, the number of bridging parts, and the distribution thereof over the entire contact surface, can likewise be selectively defined between the spring leaves and/or between the respective spring leaf and the clamping part of the clamp.

Since the columnar bridging part is guided inside the spring leaves, the leaf spring assembly configured in this manner also has a compact design.

Another embodiment includes a plurality of bridging parts, the ends on the spring leaf side facing the first spring leaf and/or the ends on the clamping part side facing the clamping part are attached to the first spring leaf or the clamping part in a force-transmitting manner with insertion of a joint planar pressure plate. The pressure plate may be produced from a metal material or a dimensionally stable plastic, achieving a more uniform clamping force distribution between the first spring leaf or the clamping part and all bridging parts.

One embodiment includes the bridging parts connected to the planar pressure plate in a substance-bonded or form-fitting manner, for example connected thereto by adhesion, welding, screwing, and riveting. A direct, integral embodiment of the planar pressure plate with corresponding bridging parts is likewise possible.

The columnar bridging part may also be configured with a hollow interior, reducing the total weight of the leaf spring assembly. With a hollow, columnar bridging part, a part of the clamp may extend through the hollow or cavity. The clamp may include a clamping part configured in a structurally particularly simple manner, for example, a bolt guided through the hollow or cavity of the bridging part and through corresponding through-openings in the first spring leaf, wherein a screw head configured on one end of the bolt and a threaded nut screwed onto a threaded portion of the bolt formed on the opposite end exert a clamping force on the at least two spring leaves, to press them together.

A further embodiment of the invention includes the clamp having a U-shaped bolt as a first clamping part surrounding the two spring leaves on three sides, wherein in open side of the U-shaped bolt is closed by a clamping plate, secured by threaded nuts as second clamping parts on the free ends of the U-shaped bolt, lying adjacent to one of the two spring leaves as the third clamping part. The clamping plate is preferably a constituent of the wheel carrier to be attached to the leaf spring or the vehicle axle. By corresponding tightening of the threaded nuts, the total clamping force exerted by the fastening clamping means on the at least two spring leaves can be selectively defined.