Coupling device for connecting a leaf spring to a wheel carrier of a motor vehicle wheel suspension and motor vehicle wheel suspension with such a coupling device

Abstract

Coupling device (40) for connecting a leaf spring (20) to a wheel carrier (10) of a motor vehicle wheel suspension (1), wherein the coupling device (40) is designed as a component comprising: a first end section (41) which has fastening devices (41a) for coupling with the wheel carrier (10), a second end section (42) for receiving an end section (22) of the leaf spring (20), characterized in that the coupling device (40) further comprises a fastening section (43) which has fastening devices (43a) for connecting a vibration damper (30), wherein this fastening section (43) for connecting the vibration damper (30) is arranged between the first end section (41) for coupling with the wheel carrier (10) and the second end section (42) for receiving the end section (22) of the leaf spring (20).

Description

The invention relates to a coupling device for connecting a leaf spring to a wheel carrier of a motor vehicle wheel suspension with the features of the preamble of claim 1. Furthermore, the invention relates to a motor vehicle wheel suspension with such a coupling device. Vehicle wheel suspensions with a so-called X-spring system represent an interesting alternative to conventional wheel suspensions such as multi-link axles with leaf springs. In a vehicle wheel suspension with an X-spring system, the suspension spring, which is usually a coil spring in conventional wheel suspensions and supports the chassis against the vehicle body, is replaced in this case by an X-shaped arrangement of leaf springs, with the leaf springs extending predominantly in the transverse direction of the vehicle. A coupling device of the type mentioned above, as well as a wheel suspension with such a device, are both known within the context of an X-spring system from the generic documents DE 10 2016 220 325 A1, DE 10 2018 215 111 B3 and DE 10 2020 207 153 A1. The coupling device is in each case a component against which an end section of the leaf spring is clamped at one end and which is pivotally connected to the wheel carrier at the other end. Instead of an X-arrangement of the leaf springs, other configurations with leaf springs running in the transverse direction of the vehicle are also possible. Another motor vehicle wheel suspension with a transverse leaf spring is known from DE 10 2014 205 635 A1. This suspension has a wheel carrier which is supported on a subframe via a lower and an upper control arm. The transverse leaf spring connects both sides of the wheel and extends under the subframe, against which it is also supported. The ends of the transverse leaf spring are each articulated to the upper control arm via a lever and corresponding joints. A vibration damper is supported directly on the wheel carrier, for which a corresponding attachment point must be provided on the latter. The present invention relates to the connection area of ​​the leaf spring to a wheel carrier of the wheel suspension. The invention aims to enable a large damper length and reduce the overall weight of the wheel suspension in a motor vehicle wheel suspension with at least one leaf spring extending predominantly in the transverse direction of the vehicle. This problem is solved by a coupling device according to claim 1 and by a motor vehicle wheel suspension with such a coupling device according to claim 10. This allows for a low, wheel-side mounting of the shock absorber, which is advantageous in terms of the vehicle's vertical alignment and in turn permits a desirable long shock absorber length. A long shock absorber length is beneficial in a wheel suspension. The solution according to the invention is particularly suitable for the series production of motor vehicles when different axle types are to be used optionally for the same vehicle body. The different spatial conditions of a leaf spring axle variant, compared to a multi-link axle, make it more difficult to accommodate the vibration damper in the latter. With the coupling device proposed here, a position of the wheel-side damper connection point comparable to that of a multi-link axle is made possible, thus eliminating the need for modifications to the vehicle body or the vibration damper for the leaf spring axle variant in order to ensure sufficient damping performance. A further advantage of the solution according to the invention is that it allows for a lower overall weight of a wheel suspension than would be possible if the vibration damper were attached directly to the wheel carrier. In that case, the wheel carrier would have to be equipped with corresponding mounting structures, which would result in a greater increase in weight on the wheel carrier side than on the coupling device. Compared to a conventional spring link, such as that used in a multi-link axle, this results in a further weight advantage. Specific embodiments of the invention are the subject of further patent claims. To accommodate the end section of the leaf spring, the second end section of the coupling device can have a preferably slot-shaped recess for the end section of the leaf spring to be held against its face. This allows for a very stable attachment of the leaf spring to the coupling device, as the leaf spring can be held against it from two opposite sides. In another particular embodiment of the invention, the coupling device has two legs and a crossbar connecting them to form a U-shape. The legs have, at their free end sections, the first end section with the fastening devices for coupling to the wheel carrier. This structure enables high rigidity with very low component weight. Preferably, the crossbeam widens the second end section to accommodate the end section of the leaf spring. In another particular embodiment of the invention, the crossmember has a slot-shaped recess on a side facing away from the legs. This facilitates the mounting of the three structures that engage with the coupling device, namely the wheel carrier, the leaf spring, and the vibration damper. In one embodiment, the slot-shaped recess is formed by two opposing flanks that form a flat contact surface against the leaf spring. Optionally, the two flanks are connected at the base of the recess by an end wall positioned opposite the end face of the leaf spring. This allows for a stable yet simple mounting and securing of the leaf spring to the coupling device. The mounting points for attaching a vibration damper can be formed very simply and without adding weight by means of through-holes in the legs. These through-holes are arranged between the mounting points for coupling to the wheel carrier and the slot-shaped recess. Furthermore, the distance between the legs on the mounting devices for attaching the vibration damper can be greater than on the mounting devices for attaching the wheel carrier, so that, if necessary, parts of a reservoir tube of the vibration damper can extend between the legs of the coupling device in order to achieve a particularly long damper length. With regard to a wheel-side damper mounting point that is low in the vehicle's vertical direction, the mounting devices for attaching the vibration damper can be located perpendicular to the legs in the direction of view, either on or below a straight imaginary line that passes through both the mounting devices for attaching the wheel carrier and the recess for enclosing the leaf spring. The coupling device can advantageously be manufactured as a one-piece cast part. However, it is also possible to manufacture these components as particularly lightweight sheet metal parts, in which the fastening devices for coupling to the wheel carrier and the fastening devices for attaching the vibration damper are formed on a first sheet metal element, and the flanks and the end wall for defining the slot-shaped recess are formed by a separate second sheet metal element, wherein the second sheet metal element is connected to the first sheet metal element, in particular by welding. This division is advantageous from a manufacturing perspective and promotes stiffness at a low weight, since the second sheet metal element stiffens the first sheet metal element. The aforementioned problem is further solved by a motor vehicle wheel suspension according to claim 10. This suspension comprises, for each wheel side, a wheel carrier, a leaf spring, a vibration damper, and a coupling device of the type described above, wherein the coupling device is coupled to the wheel carrier at its first end section, in particular by a pivot connection, clamps an end section of the leaf spring at its second end section, and is coupled to the vibration damper at its mounting section, and wherein a space is formed within the coupling device between the first end section and the second end section, and the vibration damper extends into this space. Compared to conventional multi-link axles with coil springs and steel coil springs, this motor vehicle wheel suspension is characterized by a reduced overall weight. The invention will now be explained in more detail with reference to exemplary embodiments illustrated in the drawing. The drawing shows: Fig. 1 an exemplary embodiment of a motor vehicle wheel suspension according to the invention, in which only one wheel side is shown; Fig. 2 a three-dimensional view of a first exemplary embodiment of a coupling device according to the invention; Fig. 3 a side view of the coupling device according to Fig. 2; Fig. 4 a three-dimensional view of a second exemplary embodiment of a coupling device according to the invention; and Fig. 5 a side view of the coupling device according to Fig. 4. The embodiments described relate to a motor vehicle wheel suspension 1 for passenger cars and light commercial vehicles. This motor vehicle wheel suspension 1 comprises, on each side of the wheel as shown in Fig. 1, a wheel carrier 10, a leaf spring 20, a vibration damper 30 and a coupling device 40. The coupling device 40 serves to couple the leaf spring 20 and the vibration damper 30 to the wheel carrier 10. The leaf spring 20 and the vibration damper 30 are further supported against a vehicle body or a subframe attached to it. The wheel carrier 10, the leaf spring 20, and the vibration damper 30 can, for example, be designed as described in DE 10 2016 220 325 A1, DE 10 2018 215 111 B3, and DE 10 2020 207 153.5 A1, the content of which is hereby expressly incorporated into the present disclosure. The leaf spring 20 connected to the coupling device 40 is shown there in each case within the framework of an X-spring assembly, which has two leaf springs per wheel side made of a fiber-reinforced plastic, for example, glass fiber reinforced plastic (GFRP) or carbon fiber reinforced plastic (CFRP), which extend predominantly in the transverse direction y of the vehicle. As indicated in Fig. 1, the two leaf springs 20 and 21 are arranged one above the other. They are joined at an end furthest from the wheel for support on the vehicle body side. A wheel-side end section 22 of the lower leaf spring 20 is connected to the coupling device 40 for wheel-side support, whereas the upper leaf spring 21 can be supported on the vehicle body side with its wheel-side end section 23. However, the invention is not limited to the use of such an X-spring device, but can rather be used wherever a leaf spring 20 extending predominantly in the transverse direction y of the vehicle is to be coupled with a wheel carrier 10. As already mentioned, the coupling device 40 serves not only to couple the leaf spring 20 with the wheel carrier 10, but also to connect the vibration damper 30 to the wheel side, so that the latter has a particularly low wheel-side connection point in the vehicle's vertical direction z, which allows for a large damper length. In the embodiment shown in Fig. 1, this connection point is located below the wheel center A in the vehicle's vertical direction z. Preferably, it is also offset from the wheel center A in the vehicle's longitudinal direction x, opposite to the direction of travel. In Fig. 1, the wheel-side damper connection point is located behind and below the wheel center A. The vibration damper 30 is supported on the wheel carrier 10 by means of the coupling device 40. For this purpose, the wheel carrier 10 forms a cantilever arm 12 projecting from its wheel hub section 11. By connecting the vibration damper 30 to the coupling device 40, dedicated connection structures for the vibration damper 30 on the wheel carrier 10 are no longer necessary, thus saving weight on the wheel carrier 10. The coupling device 40, which is shown in two embodiments in Fig. 2, Fig. 3, Fig. 4 to Fig. 5, has a first end section 41 with fastening devices 41a for coupling with the wheel carrier 10. The first end section 41 can be designed in the form of a fork. Fastening devices 41a can be provided in the form of through openings 41b, through which the coupling device 40 is fastened to the wheel carrier 10 by means of one or more bolts 50. The fastening can be designed as a hinge. In the embodiment shown in Fig. 1, the fork-shaped first end section 41 encompasses the free end of the cantilever arm 12 on both sides in the longitudinal direction x of the vehicle. A bolt 50 is passed through the through-openings 41b and through the cantilever arm 12 in the longitudinal direction x of the vehicle and forms a pivot axis. Furthermore, the coupling device 40 has a second end section 42 for receiving the end section 22 of the leaf spring 20. In particular, the end section 22 of the leaf spring 20 can be clamped to the second end section 42 of the coupling device 40. Fig. 1 shows, by way of example, two clamping bolts 60, which extend essentially in the vertical direction z of the vehicle through the second end section 42 and the leaf spring 20. Furthermore, a fastening section 43 is provided on the coupling device 40, which has fastening devices 43a for connecting the vibration damper 30. The fastening devices 43a for the vibration damper 30 are exemplified as through-openings 43b through which a pivot pin 70 passes. The pivot pin 70 extends through a pivot eye 31 provided on the vibration damper 30. The pivot axis of the pivot pin 70 preferably runs predominantly in the longitudinal direction x of the vehicle. As can be clearly seen in Fig. 1, the fastening section 43 for connecting the vibration damper 30 is spatially arranged between the first end section 41 for coupling with the wheel carrier 10 and the second end section 42 for receiving the end section 22 of the leaf spring 20. Within the coupling device 40, a space 2 is formed between the first end section 41 and the second end section 42, into which the vibration damper 30 extends. In one embodiment, the coupling device 40 has a U-shape when viewed along the vehicle's vertical axis z. As shown particularly in Figures 2 and 4, this U-shape can be formed by two legs 44 and a cross member 45 connecting them to form the U-shape. The aforementioned gap 2 is bounded in the longitudinal direction x of the vehicle by the legs 44, but is open upwards and downwards, i.e., in the vehicle's vertical direction z and in the vehicle's transverse direction y towards the wheel side. The legs 44 have at their free end sections the first end section 41 with the fastening devices 41a for coupling with the wheel carrier 10. The traverse 45 is located on the second end section 42 to accommodate the end section 22 of the leaf spring 20. The fastening section 43 with its fastening devices 43a for the vibration damper 30 is also located on the legs 44, preferably in a central section between the first end section 41 and the crossbeam 45. To accommodate the end section 22 of the leaf spring 20, the second end section 42 or the cross member 45 of the coupling device 40 can have a slot-shaped recess 46 which surrounds the end section 22 of the leaf spring 20 at its end face. This slot-shaped recess 46 is preferably arranged on a side of the traverse 45 facing away from the legs 44. In particular, the slot-shaped recess 46 can be formed by two opposing flanks 46a to form a flat contact against the leaf spring 20. If necessary, as shown in particular in Fig. 4, the two flanks 46a in the groove base of the recess 46 can be connected by an end wall 46b, which in the installation position of the coupling device 40 is placed opposite an end face of the leaf spring 20. The flanks 46a are penetrated by through openings 47 for the clamping bolts 60. The coupling device 40 can be designed as a one-piece cast part, as shown by way of example in Fig. 2 and Fig. 3. Figures 4 and 5 show, as an alternative, an embodiment of the coupling device 40 as a sheet metal component, which has two sheet metal elements joined together. On a first sheet metal element, which may have been stamped from a circuit board and bent into a U-shape, the fastening devices 41a for coupling with the wheel carrier 10 and the fastening devices 43a for connecting the vibration damper 30 are formed. The flanks 46a and any end wall 46b to limit the slot-shaped recess 46 are formed by a separate second sheet metal element. The second sheet metal element is connected to the first sheet metal element, for example by welding it. With regard to the mounting of the vibration damper 30 between the legs 44, the distance between the legs 44 at the fastening devices 43a for attaching the vibration damper 30 can be greater than at the fastening devices 41a for attaching the wheel carrier 10. Furthermore, with a view to achieving the lowest possible wheel-side mounting point for the vibration damper 30, the fastening devices 43a for attaching the vibration damper 30 can be located perpendicular to the legs 44 in the direction of view, as shown in Figs. 3 and 5, on or below a straight imaginary line e, which runs both through the fastening devices 41a for attaching the wheel carrier 10 and through the recess 46 for enclosing the leaf spring 20. The latter can be referenced to the center in the groove base. The coupling device 40 described above, as well as its integration into a motor vehicle wheel suspension 1 with a transverse leaf spring 20, enables a low wheel-side connection of the vibration damper 30 with respect to the vehicle's vertical direction z, and thus a large length of the vibration damper 30. Especially in the series production of motor vehicles, where different axle types are to be used optionally for a single vehicle type with the same vehicle body, the coupling device 40 enables an advantageous arrangement of the vibration damper 30 without further modifications to the vibration damper 30 or the vehicle body. This makes it possible, for example, to optionally install either a leaf spring axle or a multi-link axle without additional effort with regard to the vibration damper 30 and the vehicle body, while achieving comparable damping characteristics. Moreover, the coupling device 40 described above enables a reduction in the overall weight of a leaf spring axle, since any slight additional weight on the coupling device 40 due to the connection of the vibration damper 30 is more than compensated for by savings in the weight of the wheel carrier 10. The invention has been explained in more detail above with reference to various embodiments and variants. These 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 embodiments, variants, and modifications, but encompasses all configurations defined by the claims. Reference symbol list 1 Motor vehicle wheel suspension 2 Space 10 Wheel carrier 11 Wheel hub 12 Cantilever arm 20 Leaf spring 21 Leaf spring 22 End section 23 End section 30 Vibration damper 31 Ball joint 40 Coupling device 41 First end section 41a Mounting device 41b Through opening 42 Second end section 43 Mounting section 43a Mounting device 43b Through opening 44 Leg 45 Crossmember 46 Recess 46a Flank 46b End wall 47 Through opening 50 Bolt 60 Tension bolt 70 Joint bolt e Imaginary straight line x Vehicle longitudinal direction y Vehicle transverse direction z Vehicle vertical direction A Wheel center

Claims

Coupling device (40) for connecting a leaf spring (20) to a wheel carrier (10) of a motor vehicle wheel suspension (1), wherein the coupling device (40) is designed as a component comprising: a first end section (41) which has fastening devices (41a) for coupling with the wheel carrier (10), a second end section (42) for receiving an end section (22) of the leaf spring (20), characterized in that the coupling device (40) further comprises a fastening section (43) which has fastening devices (43a) for connecting a vibration damper (30), wherein this fastening section (43) for connecting the vibration damper (30) is arranged between the first end section (41) for coupling with the wheel carrier (10) and the second end section (42) for receiving the end section (22) of the leaf spring (20). Coupling device (40) according to claim 1, characterized in that the second end section (42) for receiving the end section (22) of the leaf spring (20) has a slot-shaped recess (46) for the end-side enclosure of the end section (22) of the leaf spring (20). Coupling device (40) according to claim 1 or 2, characterized in that it has two legs (44) and a cross member (45) connecting these legs (44) to form a U-shape, wherein the legs (44) have at their free end sections the first end section (41) with the fastening devices (41a) for coupling with the wheel carrier (10) and the cross member (45) has the second end section (42) for receiving the end section (22) of the leaf spring (20). Coupling device (40) according to claim 3, characterized in that the traverse (45) has the slot-shaped recess (46) on a side facing away from the legs (44). Coupling device (40) according to one of claims 2 or 4, characterized in that the slot-shaped recess (46) is formed by two opposing flanks (46a) for planar contact against the leaf spring (20), wherein optionally the two flanks (46a) are connected in the base of the recess (46) by an end wall (46b) which is positioned opposite the end wall of the leaf spring (20). Coupling device (40) according to one of claims 4 or 5, characterized in that the fastening devices (43a) for connecting a vibration damper are formed by through openings (43b) in the legs (44), wherein these through openings (43b) are arranged between the fastening devices (41a) for coupling with the wheel carrier (10) and the slot-shaped recess (46). Coupling device (40) according to one of claims 4 to 6, characterized in that the distance between the legs (44) at the fastening devices (43a) for attaching the vibration damper (30) is greater than at the fastening devices (41a) for attaching the wheel carrier (10), and / or that the fastening devices (43a) for attaching the vibration damper (30) are located perpendicular to the legs (44) in the direction of view on or below a straight imaginary line (e) which passes both through the fastening devices (41a) for attaching the wheel carrier (10) and through the recess (46) for enclosing the leaf spring (20). Coupling device (40) according to one of claims 1 to 7, characterized in that it is a one-piece cast part. Coupling device (40) according to one of claims 4 to 7, characterized in that it is a sheet metal component, wherein the fastening devices (41a) for coupling with the wheel carrier (10) and the fastening devices (43a) for connecting the vibration damper (30) to a first sheet metal element are formed and the flanks (46a) and the end wall (46b) for limiting the slot-shaped recess (46) are formed by a separate second sheet metal element, wherein the second sheet metal element is connected to the first sheet metal element, in particular by welding. Motor vehicle wheel suspension (1), comprising a wheel carrier (10), a leaf spring (20), a vibration damper (30), and a coupling device (40) according to one of the preceding claims 1 to 9, wherein the coupling device (40) is coupled to the wheel carrier (10) with its first end section (41), in particular is pivotally coupled, clamps an end section (22) of the leaf spring (20) at its second end section (41), and is coupled to the vibration damper (30) with its fastening section (43), wherein an intermediate space (2) is formed within the coupling device (40) between the first end section (41) and the second end section (42), and the vibration damper (30) extends into this intermediate space (2).

Images