Motor vehicle wheel suspension with leaf spring and method for mounting such a motor vehicle wheel suspension

Abstract

Motor vehicle wheel suspension (10), comprising a leaf spring (11) made of fiber-reinforced plastic, and a leaf spring bearing (1) which is arranged at an end section (13) of the leaf spring (11) to support the leaf spring (11) against a vehicle body (2), wherein a positive-locking centering device (9) is provided between the leaf spring bearing (1) and the vehicle body (20), wherein the leaf spring bearing (1) for supporting the leaf spring (11) against a motor vehicle body (20) comprises a body-side coupling section (2) for support against the motor vehicle body (20) and at least one elastomer section (3) for compensating for displacements transverse to the support direction (A), and wherein the centering device (9) for positive engagement with a counter contour (22) located on the vehicle body side is provided on the coupling section (2), characterized by the fact that the leaf spring bearing (1) rests loosely against the vehicle body (20), the centering device (9) on the coupling section (2) is designed in such a way as to guide the coupling section (2) of the leaf spring bearing (1) in the direction of the target installation position transversely to the support direction (A) in the event of deviations from a target installation position on the vehicle body (20), and the leaf spring (1) is pre-tensioned in such a way as to keep the leaf spring bearing (1) pressed against the vehicle body (20) at all times and thereby fixed it throughout the entire compression and rebound travel of the motor vehicle wheel suspension (10).

Description

[0001] The invention relates to a motor vehicle wheel suspension according to the preamble of claim 1 and further to a method for assembling such a motor vehicle wheel suspension.

[0002] A generic motor vehicle wheel suspension is known from DE 10 2016 220 325 A1.

[0003] As explained in DE 10 2016 220 325 A1, it is generally possible to attach a free end section of the leaf spring directly to the vehicle body. In the simplest case, a corresponding fastening device consists of only one or more clamping bolts or the like. Furthermore, DE 10 2016 220 325 A1 discusses an articulated coupling to introduce an additional degree of freedom at the body-side connection point.

[0004] When a leaf spring in a motor vehicle wheel suspension compresses and rebounds, length compensation between the leaf spring's mounting points must be ensured for each compression state. To prevent binding, DE 10 2016 220 325 A1 proposes compensating for small relative movements between the leaf spring and the vehicle body via the leaf spring bearing.

[0005] DE 10 2016 220 325 A1 discloses a leaf spring bearing in this regard, which has a support body designed to be rigid in both compression and tension. This support body is supported by a first rubber buffer on the vehicle body and by a second rubber buffer on an end section of the leaf spring. Pins can be formed at the axial ends of the support body, which penetrate the respective rubber buffers and serve to fix the leaf spring bearing in position on the leaf spring and on the vehicle body, where corresponding openings are provided. The rubber buffers prevent binding during deformation and pivoting of the leaf spring 12, so that the deformation potential of the leaf spring can be fully utilized.

[0006] In mass production, there is an interest in automating the entire assembly process of a vehicle axle onto the vehicle body. The leaf spring bearing represents one of the interfaces to the vehicle body in this process.

[0007] The leaf spring bearing known from DE 10 2016 220 325 A1 cannot be reliably positioned on the vehicle body due to its pins, as dimensional deviations prevent automated assembly. Instead, the known leaf spring bearing must be manually pressed into the correct position to achieve the desired bolting position.

[0008] Various positioning and centering devices from different fields of application are known from DE 10 2008 053 ​​886 A1, CN 2 04 020 468 U and JP 2012 - 171 601 A. Furthermore, a transverse leaf spring is known from DE 10 2014 223 576 A1, which connects two control arms in a motor vehicle wheel suspension and is supported on the vehicle body by bearings that are elastic in the longitudinal and transverse directions of the vehicle, but relatively rigid in the vertical direction of the vehicle.

[0009] The invention is based on the objective of facilitating the assembly of a motor vehicle wheel suspension, which has a leaf spring with a leaf spring bearing, on the motor vehicle body.

[0010] This problem is solved by a motor vehicle wheel suspension according to claim 1.

[0011] This ensures that, during the assembly of a leaf spring-equipped vehicle wheel suspension onto the vehicle body, the leaf spring bearing reaches its desired target position on the vehicle body virtually automatically, even in the event of dimensional deviations. This results in a high degree of process reliability regarding the positioning of the leaf spring bearing on the vehicle body. Any dimensional deviations perpendicular to the support direction are compensated for during assembly by the centering device. As the leaf spring bearing approaches its target position, the centering device makes a corresponding positional correction perpendicular to the support direction until the correct target position is reached. This enables automated assembly in mass production without additional manual intervention.

[0012] Furthermore, the centering device ensures that the leaf spring bearing is fixed in its intended position on the vehicle body, transverse to the support direction, due to its positive engagement. Since the leaf spring bearing is always subjected to a compressive force in the support direction when installed, additional fasteners such as screws or similar components for fixing the leaf spring bearing to the vehicle body are unnecessary. Instead, the leaf spring bearing can be positioned and fixed solely based on the positive engagement and the compressive force. This simplifies the design of the leaf spring bearing and offers further assembly advantages, particularly in automated assembly, as an additional fastening process is eliminated; that is, a separate fastening step for securing the leaf spring bearing to the vehicle body becomes obsolete.

[0013] Advantageous embodiments of the invention are the subject of further patent claims.

[0014] According to an advantageous embodiment, the vehicle wheel suspension comprises a further leaf spring made of fiber-reinforced plastic, which together with the first leaf spring forms a V-shaped structure. The V-shaped structure is supported on the vehicle body side in the area where the two leaf springs meet, and the further leaf spring is supported on the wheel side at its free end section. In the installed position, the further leaf spring tensions the entire V-shaped structure. This makes it possible to implement a separate suspension for each wheel, potentially independent of the other wheel side.

[0015] Furthermore, the centering device on the coupling section can, for example, be designed as a recess and thus be manufactured very easily.

[0016] With a view to simple manufacturing and compact design of the leaf spring bearing, it is still possible to vulcanize the coupling section to the elastomer section.

[0017] According to a further advantageous embodiment, the coupling section can be made of a material that has a higher stiffness than the material of the elastomer body. This ensures, on the one hand, precise positioning and, on the other hand, allows for a low stiffness of the bearing, particularly in the direction transverse to the support direction, with regard to compensating for stresses. Furthermore, the leaf spring bearing remains relatively stiff in the support direction, so that the spring rate of the leaf spring is not affected in this direction.

[0018] The centering device can comprise a mandrel and a corresponding recess, with the arrangement optionally being located on the vehicle body and / or the leaf spring bearing. If a mandrel is provided on the body side, for example for the purpose of supporting a conventional coil spring, the leaf spring bearing is designed with a corresponding recess.

[0019] In particular, it is possible to use the pin of a coil spring support to also support a leaf spring bearing, so that different axles with identical body-side structures are compatible with regard to the springs used.

[0020] To facilitate reaching the target installation position, the mandrel and the corresponding recess can, for example, be conical in shape.

[0021] According to a further advantageous embodiment, the coupling section and the elastomer section have a common contact surface.

[0022] According to a further advantageous embodiment, the leaf spring bearing has an additional coupling section for attaching the leaf spring bearing to a leaf spring. The elastomer section connects the two coupling sections, namely the coupling section on the vehicle body side and the coupling section on the leaf spring side, thus providing a manufacturing- and handling-friendly interface to the leaf spring. The two coupling sections are preferably otherwise unconnected. Furthermore, it is possible to vulcanize the elastomer section directly to an end section of a leaf spring.

[0023] To solve the aforementioned problem, a method for assembling a motor vehicle wheel suspension according to claim 9 is further proposed, in which a leaf spring provided with a leaf spring bearing is mounted to the vehicle body from below by connecting the leaf spring in its relaxed state with its end section opposite the leaf spring bearing and bringing the leaf spring bearing into contact with the vehicle body, wherein the centering device guides the leaf spring bearing into the desired mounting position on the vehicle body during assembly and the leaf spring is then tensioned, whereby the leaf spring bearing is held in the desired mounting position solely by the centering and the supporting force from the preload of the leaf spring. The method can be reliably automated for mass production.

[0024] The invention will now be explained in more detail with reference to an embodiment illustrated in the drawing. The drawing shows: Fig. 1 a leaf spring bearing according to a possible embodiment of the invention in installed position on a leaf spring, Fig. 2 a motor vehicle wheel suspension according to a possible embodiment of the invention during vehicle assembly when the leaf spring bearing and the associated leaf spring are brought close to their installation location on the motor vehicle body, Fig. 3 the motor vehicle wheel suspension according to Fig. 2 during assembly when the leaf spring bearing reaches its intended mounting position on the vehicle body, with the leaf spring still relaxed, and in Fig. 4 the motor vehicle wheel suspension according to Fig. 2 after completion of the assembly of the leaf spring and its preload with the vehicle standing on the ground.

[0025] Fig. Figure 1 shows an example of a leaf spring bearing 1 for supporting a leaf spring 11 against an object in the Fig. 2 to 4 of the motor vehicle body 20 shown, which in this case also includes body-mounted components such as subframes and the like. The leaf spring bearing 1 enables advantageous mounting of a component in the Fig. 2 to 4 also shown motor vehicle wheel suspension 10 on the motor vehicle body 20 achieved.

[0026] In the illustrated embodiment, the leaf spring 11 is part of a spring assembly which consists of two leaf springs 11 and 12 on each side of the wheel. However, the leaf spring bearing 1 described in the embodiment can also be used in other spring assemblies of a motor vehicle wheel suspension, for example in those which have only a single leaf spring 11 on each side of the wheel.

[0027] The leaf springs 11 and 12 of the exemplary embodiment are preferably made of a fiber-reinforced plastic, in particular glass fiber reinforced plastic (GFRP) or carbon fiber reinforced plastic (CFRP). They can be designed in a rod or beam shape. Both leaf springs 11 and 12 are in the Fig. In the embodiment shown in Figure 1, the leaf springs are designed as separate components. It is also possible to integrate both leaf springs 11 and 12 into a single body made of fiber-reinforced plastic.

[0028] The two leaf springs 11 and 12 together form a V-shaped structure in a vertical plane. The leaf springs 11 and 12 can have different lengths and are installed one above the other in the vehicle. To form the V-shaped structure, an end section of the first leaf spring 11 and an end section of the second leaf spring 12 are joined and connected, thus forming the apex of the V-shape. The resulting V-shaped spring assembly is preferably pivotally supported on the vehicle body 20 via this apex. The opposing end sections of the leaf springs 11 and 12 form correspondingly free end sections of the V-shape. The first leaf spring 11 is supported at its free end section 13 on the vehicle body side, and the second leaf spring 12 is supported at its free end section 14 on the wheel side.Due to the shorter length of the first leaf spring 11, its vehicle body-side support point at the free end section 13 of the first leaf spring 11 is located closer to the vehicle center than the wheel-side support point of the further leaf spring 12 when the spring assembly is arranged in a transverse direction.

[0029] The V-shape can be designed such that the main extension direction of the first leaf spring 11 and the main extension direction of the second leaf spring 12 in the relaxed state of the spring assembly according to Fig. 2. enclose an acute angle α. This acute angle α is preferably in the range of 15° to 35°, so that on the one hand a low installation height can be ensured, and on the other hand sufficient deflection potential is available for energy absorption. Fig. Figure 4 shows the spring assembly in a pre-tensioned state with the vehicle standing on the ground. This corresponds to the installation position in the vehicle.

[0030] A suitable bearing device is provided at each of the aforementioned support points of the spring assembly.

[0031] In the illustrated embodiment, a first bearing device 15 is provided for the articulated connection of the tip of the V-shaped spring assembly to the vehicle body 20. This device can be designed to mutually clamp the joined end sections of the first and second leaf springs 11 and 12. By means of this clamping, a rotational movement of the second leaf spring 12, which results from its compression and deformation, can be transmitted to the first leaf spring 11 and vice versa. The clamping can be designed, in particular, as described in DE 10 2016 220 325 A1.

[0032] A second bearing device 16 for the articulated connection of the wheel-side free end section of the further leaf spring 12 to a wheel carrier 21 can, for example, be designed as a fork. The connection at this point can also be made as described in DE 10 2016 220 325 A1.

[0033] The connection of the free end section 13 of the first leaf spring 11 to the body-side is made via the leaf spring bearing 1 already mentioned above, which will now be explained in more detail below.

[0034] The leaf spring bearing 1 comprises a body-side coupling section 2 for support against the vehicle body 20 and at least one elastomer section 3 for compensating for displacements transverse to the support direction A. Furthermore, the leaf spring bearing 1 may have a leaf spring-side coupling section 4 for support against the first leaf spring 11.

[0035] The at least one elastomeric section 3 is arranged between the two coupling sections 2 and 4 and connects them to each other. The two coupling sections 2 and 4 are otherwise unconnected.

[0036] In particular, the elastomer section 3 can be vulcanized to the coupling sections 2 and 4, so that no additional fastening means are required which could impair the compact dimensions of the leaf spring bearing 1.

[0037] In a modification of the illustrated embodiment, the leaf spring-side coupling section 4 can also be omitted, in which case the leaf spring bearing 1 is connected directly to the free end section 13 of the first leaf spring 11 via the at least one elastomer section 3.

[0038] The elastomer section 3 primarily provides a desired elasticity transverse to the support direction A of the leaf spring bearing 1, in order to allow the free end section 13 to pivot slightly relative to the vehicle body 20 and, if necessary, to deflect laterally when the vehicle wheel suspension 10 compresses and rebounds.

[0039] In the support direction A, the leaf spring bearing 1 is comparatively stiff. The stiffness of the leaf spring bearing 1 in the support direction A is significantly higher than in the transverse direction, so that the spring rate of the first leaf spring 11 is affected as little as possible.

[0040] Preferably, the coupling section 2 on the body side and – if present – ​​also the coupling section 4 on the leaf spring side are made of a material that has a higher stiffness than the material of the elastomer section 3. The coupling section 2 is preferably made of an aluminum alloy or a thermoplastic, although other materials are also suitable that offer a higher stiffness than the elastomer section 3 made of an elastomer.

[0041] Furthermore, the coupling section 2 on the body side and - if present - also the coupling section 4 on the leaf spring side can each have a common contact surface 5 or 6 with the elastomer section 3.

[0042] To facilitate assembly, a centering device 9 is provided on the body-side coupling section 2 for positive engagement with a counter contour 22 located on the vehicle body.

[0043] This centering device 9 on the coupling section 2 is designed to prevent deviations of the coupling section 2 of the leaf spring bearing 1 from a nominal mounting position on the vehicle body 20, such as those caused by the Fig. 3 and Fig. 4 can be extracted, directed perpendicular to the support direction A in the direction of the intended installation position.

[0044] As the leaf spring bearing 1 and the vehicle body 20 are brought close together, the bearing-side and body-side sections of this centering device initially engage loosely. During further assembly, the centering device 9 automatically guides the leaf spring bearing 1 into its target position, even if its initial position deviates from the desired target position in the transverse direction relative to the support direction. This allows dimensional deviations during assembly to be automatically compensated without requiring additional corrective measures. The assembly is self-centering, making it highly reliable and therefore easily automated. This is particularly advantageous for automated axle assembly in series production.

[0045] In the assembled state, the positive locking also ensures that the leaf spring bearing 1 is fixed in the intended position transverse to the support direction A.

[0046] How in particular Fig. Since the centering device 9 can be removed from the body-side coupling section 2, it can be formed by a recess 9a, which is preferably conical. This allows the centering device 9 to be formed very easily on the leaf spring bearing 1, in particular on its body-side coupling section 2. Furthermore, this facilitates the guidance of the leaf spring bearing 1 into the intended mounting position on the vehicle body 20.

[0047] A corresponding pin 23 is formed or attached to the vehicle body 20 as a counterpart, with which the recess 9a engages. The pin 23 can also be designed in such a way that it can optionally serve to center a coil spring. This makes it possible to optionally install axles with coil springs and axles with leaf springs 1 on the vehicle while maintaining the interface structure on the body.

[0048] However, it is also possible to provide a projection or pin as a centering device 9 on the side of the body-side coupling section 2, which engages positively in a corresponding recess on the vehicle body 20 in order to achieve a position fixation transverse to the support direction.

[0049] If the leaf spring bearing 1 is always subjected to a compressive force from the spring assembly in the support direction A in its installed position, additional fastening means for fixing the leaf spring bearing 1 to the vehicle body 20 are unnecessary. The leaf spring bearing 1 is positioned and fixed solely by virtue of the positive engagement of the centering device 9 and the compressive force in the support direction A. This keeps the design of the leaf spring bearing 1 simple and compact. Furthermore, a fastening process that would otherwise be required during assembly is eliminated.

[0050] The sequence of assembly of the above-described motor vehicle wheel suspension 10 on the motor vehicle body 20 becomes clear from the context of the Fig. 2 to 4, whereby only the aspects relating to the leaf spring bearing 1 and the leaf springs 11 and 12 will be addressed here.

[0051] Before the spring assembly with the leaf springs 11 and 12 is installed on the vehicle body 20, the leaf spring bearing 1 is attached to the end section 13 of the first leaf spring 11. This can be done in any way with or without the leaf spring-side coupling section 4.

[0052] This pre-assembled unit, which is in Fig. The part shown in 1 is then moved into the area of ​​the vehicle body 20 and mounted on the vehicle body 20 from below.

[0053] Fig. Figure 2 shows an initial position in which the leaf springs 11 and 12 are in a relaxed state. Neither the first and second bearing assemblies 15 and 16 nor the leaf spring bearing 1 are connected in this position. The spring assembly, in particular the leaf spring bearing 1, is roughly positioned in front of the relevant support points.

[0054] By moving upwards in the direction of arrow B in Fig. 2. The leaf spring bearing 1, with its body-side coupling section 2, is brought close to the intended mounting position on the vehicle body 20. In this process, the centering device 9, with its bearing-side and body-side sections, in this example the recess 9a and the mandrel 23, engages.

[0055] As the leaf spring bearing 1 is approached, the centering device 9 automatically aligns it with the target position by automatically correcting deviations perpendicular to the support direction A, which can run essentially parallel to the mounting direction B, until the body-side coupling section 2 is in contact with the vehicle body 20, as shown in Fig. Figure 3 is shown. Additionally, the first storage unit 15 can be connected on the superstructure side. Fig. 3. Leaf springs 1 and 2 are still relaxed.

[0056] Fig. Figure 4 shows the vehicle wheel suspension 10 with the vehicle stationary. Here, the free end section 14 of the second leaf spring 12 is also connected to the wheel carrier 21 via the second bearing assembly 16. The leaf springs 11 and 12 are pre-tensioned relative to the Fig. 2 and Fig. 3. Deformed state, in which the vehicle body 20 is supported against the ground via the vehicle wheel suspension 10. Due to this preload, the leaf spring bearing 1 is pressed against the vehicle body 20 in the support direction A. The preload of the leaf springs 11 and 12 is set such that a sufficient contact force in the support direction A is maintained at the leaf spring bearing 1 throughout the entire compression and rebound range of the vehicle wheel suspension 10.

[0057] The leaf spring bearing 1 rests loosely against the vehicle body 20; it is neither bolted nor otherwise additionally fastened to the vehicle body 20 in the support direction A. The positive-locking centering device 9 prevents lateral slippage from its intended position. The leaf spring 11 holds the leaf spring bearing 1 pressed against the vehicle body 20 throughout the entire compression and rebound travel of the vehicle wheel suspension 10, thereby fixing it in place.

[0058] The leaf spring bearing 1 described above significantly simplifies the assembly of a vehicle wheel suspension 10 onto a vehicle body 20. In particular, it enables fully automated assembly of the vehicle wheel suspension 10 onto the vehicle body 20 while simultaneously ensuring a high level of process reliability. At the same time, the manufacturing and production effort for both the leaf spring bearing 1 and the vehicle wheel suspension 10 remains low. One embodiment allows for an interface configuration that permits the optional mounting of axles with coil springs and axles with leaf springs 11 on an identical body-side structure.

[0059] The invention has been explained in more detail above with reference to an exemplary embodiment and further modifications. The exemplary embodiment and the modifications serve to demonstrate the feasibility of the invention. Individual technical features, which were explained above in the context of further individual features, can also be implemented independently of these features and in combination with further individual features, even if this is not expressly described, as long as it is technically possible. The invention is therefore expressly not limited to the specifically described exemplary embodiment, but encompasses all embodiments defined by the claims. Reference symbol list 1 leaf spring bearing 2. Coupling section on the body side 3 Elastomer section 4 leaf spring-side coupling section 5 Contact area 6 Contact area 7 Curvature 8 Curvature 9 Centering device 9a Exclusion 10 Motor vehicle wheel suspension 11 leaf spring (also first leaf spring) 12 additional leaf springs (also second leaf springs) 13 Final Section 14 Final Section 15 first storage facility 16 second storage facility 20 Motor vehicle body 21 bike carriers 22 Counter contour 23 Dorn A Support direction B Mounting direction

Claims

[1] Motor vehicle wheel suspension (10), comprising a leaf spring (11) made of fiber-reinforced plastic, and a leaf spring bearing (1) which is arranged at an end section (13) of the leaf spring (11) to support the leaf spring (11) against a vehicle body (2), wherein a positive-locking centering device (9) is provided between the leaf spring bearing (1) and the vehicle body (20), wherein the leaf spring bearing (1) for supporting the leaf spring (11) against a motor vehicle body (20) comprises a body-side coupling section (2) for support against the motor vehicle body (20) and at least one elastomer section (3) for compensating for displacements transverse to the support direction (A), and wherein the centering device (9) for positive engagement with a counter contour (22) located on the vehicle body side is provided on the coupling section (2), characterized by , that the leaf spring bearing (1) rests loosely against the vehicle body (20), the centering device (9) on the coupling section (2) is designed in such a way as to guide the coupling section (2) of the leaf spring bearing (1) in the direction of the target installation position transversely to the support direction (A) in the event of deviations from a target installation position on the vehicle body (20), and the leaf spring (1) is pre-tensioned in such a way as to keep the leaf spring bearing (1) pressed against the vehicle body (20) at all times and thereby fixed it throughout the entire compression and rebound travel of the motor vehicle wheel suspension (10). [2] Motor vehicle wheel suspension according to claim 1, characterized bya further leaf spring (12) made of fiber reinforced plastic, which together with the first leaf spring (11) forms a V-shaped structure, wherein the V-shaped structure is supported on the vehicle body side in the area of ​​the joined ends of the two leaf springs (11, 12) and the further leaf spring (12) is supported on the wheel side at its free end section (14). [3] Motor vehicle wheel suspension (10) according to claim 1 or 2, characterized by , that the centering device (9) on the coupling section (2) is designed as a recess (9a). [4] Motor vehicle wheel suspension (10) according to one of claims 1 to 3, characterized by , that the coupling section (2) is vulcanized to the elastomer section (3). [5] Motor vehicle wheel suspension (10) according to one of claims 1 to 4, characterized by , that the coupling section (2) consists of a material which has a higher stiffness than the material of the elastomer section (3). [6] Motor vehicle wheel suspension (10) according to one of claims 1 to 5, characterized by , that the centering device (9) comprises a mandrel (23) and a corresponding recess (9a). [7] Motor vehicle wheel suspension (10) according to claim 6, characterized by , that the spike (23) and the corresponding recess (9a) are cone-shaped. [8] Motor vehicle wheel suspension (10) according to one of claims 1 to 7, characterized by , that the leaf spring bearing (1) has a further coupling section (4) for attaching the leaf spring bearing (1) to the leaf spring (11) and the elastomer section (3) connects the two preferably otherwise unconnected coupling sections (2, 4) to each other. [9] Method for assembling a motor vehicle wheel suspension according to any one of claims 1 to 8, wherein the leaf spring (11) provided with the leaf spring bearing (1) is mounted from below on the vehicle body (20) by connecting the leaf spring (11) in its relaxed state with its end section opposite the leaf spring bearing (1) and bringing the leaf spring bearing (1) into contact with the motor vehicle body (20), wherein the centering device (9) guides the leaf spring bearing (1) into the required mounting position on the motor vehicle body (20) during assembly, and subsequently the leaf spring (11) is tensioned, whereby the leaf spring bearing (1) is held in the required mounting position solely by the centering and the support force from the preload of the leaf spring (11).

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