Control arm for the wheel suspension of a motor vehicle

Abstract

Wishbone (1) for a wheel suspension of a motor vehicle, with - a handlebar body (2) formed from an upper half-shell (3) and a lower half-shell (4), - two chassis-side connection points (5, 6) for a chassis arranged along a chassis pivot axis (A), and - two wheel-side connection points (7, 8) for a wheel carrier arranged along a wheel carrier pivot axis (B), characterized in that the wheel-side connection points (7, 8) are arranged at opposite ends of a wheel-side tube (11) which is rigidly connected to the control arm body (2) over at least a major part of its length, wherein the wheel-side tube (11) is welded to both half-shells (3, 4) and bearing elements (12, 13) for connection to the wheel carrier are arranged at the wheel-side connection points (7, 8), which bearing elements allow a pivoting movement about the wheel carrier pivot axis (B) which runs through the wheel-side tube (11).

Description

[0001] The invention relates to a wishbone for a wheel suspension of a motor vehicle having the features of the preamble of claim 1.

[0002] In modern motor vehicles, all wheels are connected to the vehicle body, i.e. to the body or chassis of the vehicle, via a wheel suspension. This type of suspension primarily fulfils two functions: firstly, the guidance of the wheel carrier or wheel, and secondly, its suspension. The guidance of the wheel carrier is primarily ensured by more or less horizontal control arms (e.g. wishbones or trailing arms) via which the wheel carrier is connected to the chassis. One or more wishbones connect the wheel carrier to vehicle-side components of the chassis, e.g. a side member, a subframe, etc. The main function of the wishbone is to absorb horizontal forces (i.e. those lying in the XY plane) together with other suspension components. Such a wishbone typically has two chassis-side connection points and one or two wheel-side connection points.The chassis-side connection points, through which an articulated connection is established, e.g., through metal-rubber composite bearings, define a pivot axis through their relative arrangement. When installed, this axis normally corresponds to the X-axis (i.e., the longitudinal axis) of the vehicle or is arranged at an angle to it in the XY plane. The pivoting movement of the wishbone relative to the chassis occurs around this axis when the wheel is compressed. The wheel-side connection point(s) ensure the pivoting of the wheel carrier relative to the wishbone.

[0003] In addition to forged wishbones, which are usually made of light metal or steel, control arms manufactured as single- or double-shell sheet metal parts are also known in the art. To give such a control arm the necessary strength, the sheet metal is profiled through a suitable forming process (e.g., drawing), giving it a shell-like structure. Furthermore, control arms are also known that are made at least partially of fiber-reinforced plastic.

[0004] Furthermore, modern vehicles feature stabilizers as part of the chassis. These stabilizers connect opposing wheels on an axle. They do this in such a way that, when the suspension is compressed on one side, a force is transferred to the opposite wheel (usually via torsion of the stabilizer), thereby providing a degree of compensation and reducing the vehicle's lean angle. Such stabilizers are typically connected to the respective wishbone via downward-running coupling rods.

[0005] A special type of control arm is the lower wishbone of a trapezoidal-link rear suspension. Various requirements apply to this. Firstly, it should exhibit high lateral stiffness along the Y-axis (transverse axis), and secondly, it should exhibit high torsional stiffness around the Y-axis. Furthermore, reducing manufacturing costs is naturally just as desirable as minimizing the weight of the control arm in order to reduce overall vehicle weight and the associated fuel consumption.

[0006] DE 10 2013 205 686 A1 discloses a spring link for the wheel suspension of a motor vehicle, comprising a base plate section and two side wall sections, which together form a one-piece, elongated sheet metal shell with a U-shaped cross-sectional profile that is widened in a longitudinally central section relative to a body-side end section and a wheel carrier-side end section of the sheet metal shell. The U-shaped cross-sectional profile is bridged on both sides of the central section by a flat sheet metal strip, which connects the leg ends of the U-shaped cross-sectional profile to each other. Each sheet metal strip is an integral extension of one of the two side wall sections and is connected to the other of the two side wall sections by a weld seam.A connecting element comprising an outer steel cylinder welded to the end portion may be welded to a distal end of the wheel carrier-side end portion.

[0007] DE 10 2012 214 352 A1 discloses an independent wheel suspension for a commercial vehicle, with a steering knuckle arranged on a steering knuckle pin so as to be rotatable about a first axis of rotation, with a wheel hub, a steering knuckle support connected to the steering knuckle by the steering knuckle pin, a vibration damper and a spring element, which can each be fixed on the one hand to a fastening element on the steering knuckle support and on the other hand to a further fastening element of the vehicle body, at least one upper wishbone and at least one lower wishbone.

[0008] DE 10 2012 200 001 A1 discloses a rubber-metal bearing for a wheel suspension of a motor vehicle, comprising an elastic rubber body arranged between an outer bushing and an inner bushing coaxially aligned therewith and fastened thereto. The outer bushing has a front end face to which at least one front elastic rubber damping element is attached, and a rear end face to which at least one rear elastic rubber damping element is attached. The front and rear rubber damping elements are arranged asymmetrically to one another.

[0009] DE 10 2010 051 884 A1 discloses a method for producing a wishbone made from a light metal extruded profile and having a base body with bearing arms extending therefrom. A semi-finished product made from a light metal extruded profile with at least three adjacent hollow chambers is provided, and the top and bottom sides of the central chamber are trimmed so that the outer chambers form projecting bearing arms. The bearing arms are then bent before connection receptacles are formed at their ends. The wishbone can, in particular, be X-shaped.

[0010] DE 10 2005 036 931 B4, which could be considered the closest prior art, discloses a control arm for a wheel suspension comprising two welded sheet metal half-shells and two connections for attaching a wheel carrier. The connections are formed by two outer flat sheet metal tongues that enclose two inner flat sheet metal tongues. The sheet metal tongues are each formed integrally with one of the half-shells. Optionally, the outer and inner sheet metal tongues can be welded together.

[0011] In view of the state of the art shown, there is still room for improvement in providing a wishbone, particularly for a rear wheel suspension, which is lightweight with optimal stiffness and can be manufactured cost-effectively.

[0012] The invention is based on the object of optimising the weight and manufacturing costs of a wishbone while ensuring optimal mechanical properties.

[0013] According to the invention, the object is achieved by a wishbone having the features of claim 1.

[0014] Shown is a wishbone for a wheel suspension of a motor vehicle, with a control arm body formed from an upper half shell and a lower half shell, two chassis-side connection points for a chassis arranged along a chassis pivot axis, as well as two wheel-side connection points for a wheel carrier arranged along a wheel carrier pivot axis. According to the invention, the wheel-side connection points are arranged at opposite ends of a wheel-side tube that is rigidly connected to the control arm body over at least a predominant part of its length. The wheel-side tube is welded to both half-shells, and bearing elements for connection to the wheel carrier are arranged at the wheel-side connection points, allowing a pivoting movement about the wheel carrier pivot axis, which runs through the wheel-side tube.

[0015] The subclaims relate to advantageous embodiments of the invention.

[0016] It should be noted that the features and measures listed individually in the following description can be combined with one another in any technically reasonable manner and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0017] The invention provides a wishbone for a wheel suspension of a motor vehicle. Suitable motor vehicles in this case are, in particular, cars or trucks. This can, in particular, be a rear wheel suspension. In particular, it can be a lower wishbone.

[0018] As mentioned above, the wishbone has a control arm body consisting of an upper half-shell and a lower half-shell. This corresponds to the two-shell construction known in the prior art, with the two half-shells normally being made of sheet steel, although a construction made of fiber-reinforced plastic or a light metal such as aluminum would also be conceivable. The control arm body formed by the half-shells is usually flat or planar, i.e., it extends in one plane (e.g., in the XY plane) and has a significantly smaller extension transverse to this plane (e.g., along the Z axis).

[0019] The half-shells more or less completely enclose an inner cavity of the control arm, with each of the half-shells normally having a flange at the edge. In principle, they can be connected to one another using various positive, non-positive, and / or material-fit joining methods, although the connection is always rigid. A common type of connection for sheet metal half-shells is edge welding. It is understood that the term "half-shells" should not be interpreted to mean that each of the two shells takes up half of the surface of the control arm or the like, but rather that they together form a shell of the control arm body. The position specifications "upper / lower half-shell" refer to the installation position of the control arm, in which it extends approximately within the XY plane, as is known in the art, with one of the half-shells being on top in the Z-axis direction and the other at the bottom.

[0020] As already mentioned, the wishbone has two chassis-side connection points for a chassis, arranged along a chassis pivot axis, and two wheel-side connection points for a wheel carrier, arranged along a wheel carrier pivot axis. These connection points are points or areas where a direct or indirect connection to the wheel carrier or chassis can be established, or where the corresponding connection is established when installed. Such a connection point can be provided, for example, by a bearing bush, a bearing journal, a ball joint mount, or similar. In total, the wishbone therefore has four connection points. One could also say that the respective connection points define the course of the respective pivot axis.

[0021] The chassis-side connection points are used to pivot the connection to the vehicle's chassis, and therefore also to the vehicle's subframe. The wishbone is connected to the chassis or subframe via these connection points in such a way that it can pivot about the chassis pivot axis. This normally runs within the XY plane, but not necessarily parallel to the X-axis (longitudinal axis) of the vehicle. The wheel-side connection points are used to pivot the connection to the wheel carrier. The wheel carrier can be attached here in such a way that it can pivot about the wheel carrier pivot axis relative to the wishbone. Normally, the chassis pivot axis and the wheel carrier pivot axis lie in the same plane with respect to the wishbone. If necessary, the wheel carrier pivot axis can run parallel to the X-axis when the wishbone is in a horizontal position. The two pivot axes can run parallel or at an angle to each other.

[0022] As mentioned above, the wheel-side connection points are arranged at opposite ends of a wheel-side tube that is rigidly connected to the control arm body. The tube is preferably designed as a single piece, but can also be formed from interconnected segmented shells. The tube can also be formed from just one segmented shell, so that the tube is open on one side, either towards the wheel carrier or away from the wheel carrier. The rigid connection ensures that forces acting on the tube are transmitted further into the control arm body. It is also preferably provided that the force flow runs from the wheel-side connection points via the tube to the control arm body. The tube forms a very stable structure that contributes overall to the stabilization of the wishbone. This applies in particular to forces acting transversely to the direction of travel of the tube or to the torques resulting from them.

[0023] The wheel-side tube is connected to the handlebar body over at least a large part of its length. In principle, it can have a polygonal, oval, or other cross-section, but the cross-section is typically circular. In this case, it is a standard component that is cost-effective to manufacture. The tube is normally made of sheet steel, although other materials such as light metals or fiber-reinforced plastic are also suitable. In particular, the tube can also help to distribute stresses that may occur locally at just one of the wheel-side connection points, thus preventing excessive local loading of the handlebar body. Overall, the forces acting at the wheel-side connection points are primarily absorbed by the tube and thus act more evenly on the handlebar body. Normally, the tube is oriented at a relatively large angle to the Y-axis; if necessary,even at right angles to it. This also improves the torsional rigidity of the wishbone around the Y-axis. The wishbone is simple and inexpensive to manufacture.

[0024] Furthermore, as already described above, bearing elements for connection to the wheel carrier are arranged at the wheel-side connection points. These bearing elements allow a pivoting movement about the wheel carrier pivot axis, which runs through the wheel-side tube. The bearing elements can be designed, for example, as rubber-metal bearings, ball joints, pivot bearings or ball bearings or parts thereof. They can, for example, comprise a bushing that is rotatably mounted on an axis. Some of the bearing elements can be rigidly connected to the wheel carrier in the assembled state. In any case, the bearing elements as a whole allow a pivoting movement of the wheel carrier and the wishbone relative to one another about the wheel carrier pivot axis. This axis runs through the wheel-side tube, for example along its axis of symmetry.

[0025] The wheel-side tube is welded to both half-shells. This ensures a materially bond between the tube and both half-shells, and also provides a particularly secure connection between the two half-shells. This creates a particularly stable bond between the three elements in the connecting area.

[0026] It is possible for the bearing elements to be individually attached to the wheel-side tube. According to another embodiment, the bearing elements are connected to one another via a connecting arrangement that runs through the tube. This means that the connecting arrangement serves at least to secure the bearing elements at opposite ends of the tube in their position relative to one another and relative to the tube. In this case, it is conceivable that the connecting arrangement still allows a certain degree of relative movement, thus leaving the bearing elements some play. If necessary, the connecting arrangement can also brace the bearing elements against the wheel-side tube, with a screw and a nut exerting a force that pulls the bearing elements against the tube and thus secures them in position.

[0027] The aforementioned embodiment can be easily implemented by enclosing the screw within the wheel-side tube. The head of the screw can rest against a bearing element at one end of the wheel-side tube, while the nut rests against a bearing element at the other end of the wheel-side tube. Of course, elements known in the art, such as washers or the like, can be interposed. Because the bearing elements on both sides of the wheel-side tube are secured by a single screw and associated nut, the number of parts is kept to a minimum, simplifying assembly.

[0028] In order to secure the position of the screw in the operating state on the one hand and to facilitate insertion of the screw into the wheel-side tube during assembly on the other, it is preferred that the wheel-side tube has a centering element for centering the screw. The centering element can be, for example, a closure cap that is placed on or inserted into one end of the wheel-side tube and that has a (central) opening for the screw to pass through. In particular, the centering element can be arranged at least partially in the wheel-side tube. It can extend along the entire length of the tube or just along part of it. Multiple centering elements can also be present. If the centering element is located inside the wheel-side tube, its outer dimensions are of course adapted to the inner dimensions of the tube and it has a recess inside that is adapted to the outer dimensions of the screw.

[0029] According to one embodiment, chassis-side tubes are arranged at the chassis-side connection points, which are rigidly connected to the half-shells. These tubes can serve, as is known in the prior art for wishbones, to accommodate rubber-metal bearings that are pressed into them. These tubes can, as is also known in the prior art, be cylindrical in shape. The axes of symmetry of the tubes do not have to be aligned parallel to the chassis pivot axis, but can be at an angle to it.

[0030] Optionally, it can be provided that a stabilizer, which connects the suspension of one wheel in a known manner to the suspension of the opposite wheel, is at least indirectly connected to the wishbone. For this purpose, according to one embodiment, a bracket for at least indirectly connecting a stabilizer is rigidly connected to the control arm body. Normally, it is provided that a downwardly extending coupling rod, which in turn is connected to the stabilizer, engages the corresponding bracket. The bracket can be designed as a sheet metal part having a bore. The sheet metal part can in particular run parallel to the direction in which the main force components act on the part of the stabilizer, i.e., for example, approximately vertically.

[0031] The bracket can be connected to one or both of the half-shells. The connection can be force-fitting, form-fitting, and / or material-fitting. Preferably, the bracket is welded to the handlebar body. According to one embodiment, the bracket is partially arranged between the half-shells and welded to them. This means that a recess is provided in the connecting area of ​​the two half-shells, through which the bracket protrudes from the inside to the outside. The inner part of the bracket allows for improved contact with the half-shells, making the connection more stable overall.

[0032] In a further embodiment of the invention, the chassis pivot axis and the wheel carrier pivot axis converge toward each other toward the front. This means that the two pivot axes do not run parallel to each other (and, for example, parallel to the vehicle's X-axis), but rather at an angle, such that the distance between the (imagined extended) pivot axes decreases toward the front, i.e., toward the front of the vehicle. Typically, the two pivot axes run in one plane, so that they intersect at a point in front of the wishbone.

[0033] It should be noted again that the connection to the chassis can also be made via a subframe.

[0034] Further advantageous details and effects of the invention are explained in more detail below with reference to an embodiment shown in the figures. Fig. 1 a perspective view of a wishbone according to the invention; Fig. 2 a top view of the wishbone from Fig. 1; Fig. 3 a sectional view along the line III-III in Fig. 2; and Fig. 4 a sectional view along the line IV-IV in Fig. 2.

[0035] In the different figures, parts that are equivalent in terms of their function are always provided with the same reference symbols, so that they are usually only described once.

[0036] Fig. Figure 1 shows a perspective view of a lower wishbone 1 for a rear wheel suspension of a motor vehicle, e.g., a passenger car. The drawing shows the vehicle axles in the installed position of the wishbone 1, with the X-axis pointing toward the rear of the motor vehicle. The wishbone 1 comprises a control arm body 2, which consists of an upper half-shell 3 and a lower half-shell 4. The two half-shells 3, 4 are manufactured as formed sheet metal parts and joined together by welding. The overall structure of the wishbone 1 is planar or flat and extends predominantly in the XY plane.

[0037] A total of four connection points 5, 6, 7, 8 are arranged on the control arm body. Firstly, there are two chassis-side connection points 5, 6, to each of which a chassis-side metal tube 9, 10 is welded to both half-shells 3, 4. A chassis pivot axis A runs through the chassis-side connection points 5, 6. Each of the chassis-side metal tubes 9, 10 is connected to an arm section 2.1, 2.2 of the control arm body 2. The cross-sections of the metal tubes 9, 10 are each circular, and their axes of symmetry run at an angle to the chassis pivot axis A. In the assembled state, bushings or ball joints can be pressed into the respective metal tubes 9, 10, thus enabling a pivotable connection to a chassis of the motor vehicle. The connection can be made, for example, to a subframe.

[0038] Furthermore, two wheel-side connection points 7, 8 are provided on a wheel-side connection side 18, which are arranged on a side of the handlebar body 2 opposite the connection points 5, 6. They are located at the ends of a wheel-side, preferably one-piece tube 11, which is welded to both half-shells 3, 4 and extends in the direction of the X-axis, as can be seen in particular from the top view in Fig. 2. The tube 11 also has a circular cross-section and is preferably made of a metal, whereby the designation metal tube 11 is chosen below. The metal tube 11 has a width that corresponds at least to the width of the wheel-side connection side 18. In Fig. 1 it can be seen that the metal tube 11 slightly projects beyond the wheel-side connection side 18 on both sides.

[0039] In the area of ​​the wheel-side connection points 7, 8, a first bearing element 12 and a second bearing element 13 are arranged on the wheel-side metal tube 11. Via the bearing elements 12, 13, the wishbone 1 is fastened in the assembled state to a wheel carrier (not shown) in such a way that pivoting about a wheel carrier pivot axis B is provided. As shown in Fig. 1 and Fig. 2, the pivot axes A, B are not parallel to each other, but converge towards each other. As can be seen particularly from the sectional view in Fig. As can be seen in Figure 4, the aforementioned bearing elements 12, 13 are seated on the shaft of a long screw 14 that extends through the metal tube 11. A nut 15 is screwed onto the end of the long screw 14. The long screw 14 and the nut 15 connect the bearing elements 12, 13 to one another and to the wheel-side metal tube 11.

[0040] Pressed into the ends of the wheel-side metal tube 11 are closure caps 16, each with central openings through which the long screw 14 is inserted. The closure caps 16 can be made of metal, for example. They serve, on the one hand, to protect the interior of the metal tube 11 from penetrating dirt, and, on the other hand, to form stops for the bearing elements 12, 13. Finally, they serve as centering elements that enable the centering of the long screw 14.

[0041] Optionally, a further, e.g., cylindrical centering element or a filling material could be provided in the interior 11.1 of the metal tube 11.

[0042] To enable the connection of a stabilizer (not shown), a bracket 17 is arranged on the side of the handlebar body 2, which can also be referred to as a coupling rod bracket 17. This consists of a substantially flat sheet metal part that is thicker than the sheet metal of the half-shells 3, 4. In the operating state, a coupling rod, which in turn is connected to the stabilizer, engages in a bore 17.1 of the coupling rod bracket 17. The orientation of the coupling rod bracket 17 essentially corresponds to the main direction of the forces expected from the coupling rod. To ensure a particularly secure connection of the coupling rod bracket 17 to the handlebar body 2, the former is guided through a recess into the interior of the handlebar body 2 between the half-shells 3, 4. This is shown in the sectional view in Fig.3. In addition, the coupling rod bracket 17 is welded to both half shells 3, 4. List of reference symbols: 1 wishbone 2 handlebar bodies 2.1, 2.2 Arm section 3 upper half shell 4 lower half shell 5, 6 Chassis-side connection point 7, 8 wheel-side connection point 9, 10 Chassis-side metal tube 11 wheel-side pipe 11.1 Interior 12, 13 Bearing element 14 Long screw 15 Mother 16 Cap 17 Bracket 17.1 Drilling 18 wheel-side connection side A chassis swivel axis B Wheel carrier pivot axis X X-axis Y Y-axis Z Z-axis

Claims

[1] Wishbone (1) for a wheel suspension of a motor vehicle, with - a handlebar body (2) formed from an upper half-shell (3) and a lower half-shell (4), - two chassis-side connection points (5, 6) for a chassis arranged along a chassis pivot axis (A), and - two wheel-side connection points (7, 8) for a wheel carrier arranged along a wheel carrier pivot axis (B), characterized byin that the wheel-side connection points (7, 8) are arranged at opposite ends of a wheel-side tube (11) which is rigidly connected to the handlebar body (2) over at least a major part of its length, the wheel-side tube (11) being welded to both half-shells (3, 4) and bearing elements (12, 13) for connection to the wheel carrier being arranged at the wheel-side connection points (7, 8), which bearing elements allow a pivoting movement about the wheel carrier pivot axis (B) which runs through the wheel-side tube (11). [2] Wishbone according to claim 1, characterized by Bearing elements (12, 13) which are connected to one another via a connecting arrangement (14, 15) guided through the wheel-side tube (11). [3] Wishbone according to claim 2, characterized by that the connecting arrangement (14, 15) has a screw (14) guided through the wheel-side tube (11) and a nut (15). [4] Wishbone according to one of the preceding claims, characterized by that the wheel-side tube (11) has a centering element (16). [5] Wishbone according to one of the preceding claims, characterized by that chassis-side tubes (9, 10) are arranged at the chassis-side connection points (5, 6), which are rigidly connected to the half-shells (3, 4) and which are arranged at an angle to the chassis pivot axis (A). [6] Wishbone according to one of the preceding claims, characterized by a holder (17) which is rigidly connected to the handlebar body (2) so that a stabilizer can be connected at least indirectly to the handlebar body (2). [7] Wishbone according to one of the preceding claims, characterized by that the wheel-side tube (11) is designed in one piece and has at least one width which corresponds at least to a width of a wheel-side connection side (18). [8] Wishbone according to one of the preceding claims, characterized bythat the chassis pivot axis (A) and the wheel carrier pivot axis (B) run towards each other in the forward direction.

Images