Ball joint for a motor vehicle

Abstract

The invention relates to a ball joint (10) for a motor vehicle, in particular for a chassis of the motor vehicle, comprising: - a joint housing (1) having a joint opening in which a bearing shell (6) is arranged, - a ball pin (2) having a joint ball (4) and a pin (5), which is mounted with its joint ball (4) in the bearing shell (6) in an articulated manner and which projects with its pin (5) through the joint opening out of the joint housing (1), and - a sensor device for detecting wear, wherein the sensor device has a circuit arrangement (11) which is mechanically actuated by the joint ball (4) and which is arranged within the joint housing (1), wherein the circuit arrangement (11) can be transferred, due to wear, from a basic switching position in which an electrical circuit (21) of the circuit arrangement (11) is closed into at least two further switching positions.

Description

[0001] The invention relates to a ball joint for a motor vehicle, in particular for a chassis of the motor vehicle, comprising a joint housing having a joint opening in which a bearing shell is arranged, a ball stud having a joint ball and a stud, the ball stud being articulatedly mounted in the bearing shell with its joint ball and protruding from the joint housing through the joint opening with its stud, and a sensor device for wear detection. Furthermore, the invention relates to a method for manufacturing such a ball joint.

[0002] In automotive engineering, ball joints are used, among other things, for the articulated connection of chassis components of the wheel suspension and / or steering system, where they serve to transmit spring movements or steering movements between components that are usually movable about multiple axes. Depending on the specific application, different operating forces arise between a joint housing of the ball joint and a ball stud, which is pivotally mounted in the joint housing by means of a joint ball and extends through an opening in the joint housing.

[0003] The pivoting movements that occur during operation of the ball joint cause friction between a surface of the joint ball and the contacting surface, either of the joint housing that accommodates the joint ball, or of a bearing shell arranged in the joint housing that partially surrounds the joint ball for sliding support. As the ball joint's service life increases, the friction caused in this way leads to wear. With progressive wear, the play in the ball joint increases, thus deteriorating the precision with which the affected chassis components are connected to one another. To ensure precise steering and wheel control and thus the safety of the vehicle, it is necessary to replace a worn ball joint in the chassis in a timely manner. When installed on the vehicle, corresponding diagnosis is complex, often quite inaccurate, and can usually only be performed by a specialist.

[0004] Various sensor devices have been used to detect wear on ball joints. For example, DE 10 2008 041 050 A1 discloses a method for measuring wear on a ball joint based on magnetic field measurement.

[0005] A sensor device known from DE 10 2005 030 971 A1 is located on the outer side of a bearing shell and between the bearing shell and a joint housing that accommodates the joint ball. The sensor device is formed by a sensor arrangement comprising at least two pressure or force sensors for measuring the forces or contact pressures acting between the joint ball and the bearing shell. A disadvantage here is that the design of the respective sensor arrangement and the entire sensor device is complex and thus undesirably cost-intensive.

[0006] Furthermore, DE 100 09 054 C2 discloses a ball joint in which the joint housing and the pivot pin are connected to a potential difference measuring device by means of electrical contact elements. The joint ball and the joint housing accommodating the joint ball are electrically insulated from each other. For this purpose, the bearing shell is made of an electrically non-conductive material. Due to wear, the insulation provided by the bearing shell between the joint housing and the pivot pin is eliminated at one point or reduced to such an extent that the potential difference existing in the intact state of the ball joint is eliminated, which is considered an indicator that the ball joint needs to be repaired.Contamination over the service life of the ball joint can lead to corrosion of the contact elements, so that in the event of wear, i.e., direct mechanical contact between the electrode and the joint ball, no or only a very weak electrical contact is formed. This can lead to inaccurate measurements when determining the wear level.

[0007] Based on the prior art described above, it is now the object of the present invention to further develop a ball joint and a method for producing such a ball joint of the type mentioned at the outset in such a way that the sensor device can be produced in a simple and cost-effective manner, wherein the sensor device enables reliable detection of critical bearing play during vehicle operation.

[0008] From a device-technical perspective, this problem is solved based on the preamble of claim 1 in conjunction with its characterizing features. From a process-technical perspective, the problem is solved based on the preamble of the co-ordinate claim 15 in conjunction with its characterizing features. The dependent claims that follow therefrom each represent advantageous developments of the invention.

[0009] According to claim 1, a ball joint for a motor vehicle, in particular for a chassis of the motor vehicle, is proposed, wherein the ball joint is designed with a joint housing having a joint opening in which a bearing shell is arranged, a ball pin having a joint ball and a pin, which is mounted with its joint ball in the bearing shell in an articulated manner and with its pin protruding through the joint opening out of the joint housing, and a sensor device for wear detection.According to the invention, it is provided that the sensor device has a circuit arrangement which is mechanically actuated by the joint ball and which is arranged within the joint housing, wherein the circuit arrangement can be transferred from a basic switching position, in which an electrical circuit of the circuit arrangement is closed, into at least two further switching positions due to wear, wherein in one switching position the electrical circuit closed in the basic switching position is interrupted and in the further switching position a further circuit is closed.

[0010] What is important here is that the inventive design of the sensor device generates a signal indicating the correct functionality of the sensor device in the basic switching position, in which an electrical circuit of the circuit arrangement is closed. This makes it possible to detect a functional restriction during operation, for example due to corrosion caused by contamination of the ball joint, or a functional failure of the sensor device, for example due to an interruption of an electrical connection. On the other hand, the circuit arrangement, which can be converted into at least two further switching positions, makes it possible to detect, on the one hand, a wear-related undershoot of a limit value for bearing play, which corresponds to the joint ball wandering out of the bearing, and, on the other hand, wear of the bearing shell, which leads to the joint ball being pressed into the bearing shell.In both cases, the wear-induced movement of the joint ball leads to the switching arrangement being transferred from the basic switching position into one of at least two further switching positions due to wear.

[0011] The mechanical actuation of the circuit arrangement can occur directly or indirectly through the joint ball. Direct mechanical actuation of the circuit arrangement would be achieved through direct physical contact between the joint ball and the circuit arrangement. Indirect mechanical actuation of the circuit arrangement would be achieved through a component located between the joint ball and the circuit arrangement.

[0012] In particular, the ball joint is designed for the chassis of a motor vehicle. Ball joints can be used in a variety of ways in vehicle construction. In particular, ball joints in the chassis are used to connect chassis components, such as control arm components, wheel carriers, tie rods, or the like, to each other or to the vehicle body or an axle carrier attached to it.

[0013] The circuit arrangement preferably comprises a substantially dome-shaped switching element made of a resilient material, as well as a circuit board or foil arranged opposite the switching element. In the basic switching position, in which the circuit of the circuit arrangement is closed, the dome-shaped switching element is mechanically loaded by the joint ball such that the dome-shaped switching element generates a restoring force. In the basic switching position, in which one circuit of the circuit arrangement is closed, damage to the circuit board or foil can be detected if this leads to an interruption of the circuit.

[0014] In particular, the switching element can be made of an electrically conductive material, have an electrically conductive coating, or interconnected wires can be integrated into the switching element. This can overcome limitations in the choice of material for the spring-elastic material.

[0015] Preferably, the circuit arrangement can have at least one connection point, at which the switching element is electrically connected to at least one contact surface of the circuit board or film, as well as a first contact element that can be brought into contact with a first conductor track section on the circuit board or film, and a second contact element that can be brought into contact with a second conductor track section on the circuit board or film, wherein the at least one contact surface, the first conductor track section, and the second conductor track section are electrically insulated from one another. Preferably, the at least one contact surface can be designed as a conductor track.

[0016] In the basic switching position, the switching element can be subjected to a force by the joint ball, so that the first contact element is in contact with the first conductor track section due to the elastic deformation of the switching element and the second contact element is spaced apart from the second conductor track section.

[0017] Furthermore, the switching element can move from the basic switching position to the first switching position depending on the degree of wear of the joint ball and / or the switching element can move from the basic switching position to the second switching position depending on the degree of wear of the bearing shell.

[0018] In the first switching position of the switching element, any contact existing in the basic switching position between the first contact element and the first conductor track section on the circuit board or the foil is interrupted. This can be caused by the restoring force generated in the dome-shaped switching element in the basic switching position. If the bearing play falls below the limit value due to wear, which corresponds to the joint ball wandering out of the bearing, this leads to the first contact element moving away from the first conductor track section as the switching element springs back to its original shape and loses physical contact. This can interrupt the electrical circuit that is closed in the basic switching position in order to signal the wear of the ball joint to the outside, in particular due to the bearing play.

[0019] In the second switching position of the switching element, contact is established between the second contact element and the second conductor track section on the circuit board or film. This is caused by wear on the bearing shell, which causes the joint ball to be pressed into the bearing shell. As the bearing shell wears, the joint ball presses the dome-shaped switching element in until contact is established between the second contact element and the second conductor track section. This allows another electrical circuit to be closed to signal wear on the ball joint, particularly the bearing shell, to the outside world.

[0020] For this purpose, a device can be provided that is integrated into or connected to the circuit. The device can, for example, enable the connection of a measuring device or an evaluation device.

[0021] According to a preferred development, the switching element can have an elastically deformable concave section on which at least two support elements are arranged along its periphery.

[0022] In particular, at least one of the at least two support elements can be electrically conductively connected to the at least one contact surface on the circuit board or the film, with a further support element forming the first contact element. The at least one support element electrically conductively connected to the at least one contact surface on the circuit board or the film can be connected to the at least one contact surface, in particular by a solder joint, and form the connection point.

[0023] Furthermore, the concave portion of the switching element can form the second contact element.

[0024] Alternatively, the switching element may have a convex portion formed centrally in the concave portion, which forms the second contact element.

[0025] Preferably, at least two support elements can be electrically conductively connected to the at least one contact surface on the circuit board or the film, while a further support element forms the first contact element. The three support elements can be arranged offset from one another at an angle of approximately 120° along the periphery of the spring-elastically deformable concave section. The further support element, which forms the first contact element, differs from the other two support elements in terms of its length in order to have a spatial distance from the first conductor track section in the mechanically unloaded state of the switching element, which corresponds to the basic switching position. For this purpose, the further support element is shorter than the other two support elements.

[0026] More preferably, three support elements can be electrically connected to the at least one contact surface on the circuit board or the film, while a further support element forms the first contact element. The four support elements can be arranged offset from one another at an angle of approximately 90° along the periphery of the resiliently deformable concave section. Here, too, the support element forming the first contact element differs from the other three support elements in its shorter length, in order to maintain a spatial distance from the first conductor track section when the switching element is in the mechanically unloaded state.

[0027] Preferably, the circuit arrangement can be arranged on the bearing shell, the joint ball, or inside the joint housing. The circuit arrangement can be arranged on the side of the bearing shell facing the joint ball. In the assembled state, the joint ball presses against the switching element. Alternatively, the circuit arrangement can be arranged on the joint ball. In the assembled state, the joint ball presses the switching element against the bearing shell. According to a further alternative, the circuit arrangement can be arranged inside a wall of the joint housing surrounding the joint ball and / or the bearing shell.

[0028] In particular, the switching element can have a force-displacement characteristic curve that is dimensioned depending on its arrangement and positioning within the ball joint. This allows the arrangement and positioning of the switching arrangement on the bearing shell, the joint ball, or inside the joint housing to be taken into account.

[0029] For example, the shape, material thickness, and / or size of the switching element can be adjusted to design the force-displacement characteristic curve. The design of the essentially dome-shaped switching element is crucial for the course of the force-displacement characteristic curve. This allows a tolerance range to be specified within which any wear on the ball joint, which leads to movement of the joint ball, is tolerable. The design of the dome-shaped switching element also determines the force with which the switching element can be pressed in during installation and assembly of the ball joint so that the first contact element and the first conductor track section touch one another. This creates the basic switching position of the circuit arrangement without the dome-shaped switching element being completely compressed, which would also cause the second contact element and the second conductor track section to come into contact with one another.

[0030] In particular, the switching element can be coated with a flexible contact and protective layer on its surface in contact with the joint ball. This can at least reduce abrasion on the surface of the switching element.

[0031] Furthermore, the object stated at the outset is achieved by a method for producing a ball joint having the features of the independent claim 15.

[0032] According to claim 15, a method for producing a ball joint according to one of claims 1 to 14 is proposed, in which the ball joint is formed with a joint ball, a joint housing having a joint opening in which a bearing shell is arranged, and a sensor device for wear detection, wherein the joint ball is mounted in the bearing shell in an articulated manner.According to the invention, the sensor device has a circuit arrangement which is mechanically actuated by the joint ball, in particular directly or indirectly, and which is arranged within the joint housing, wherein the circuit arrangement is transferred, due to wear, from a basic switching position in which an electrical circuit of the circuit arrangement is closed, into at least two further switching positions, wherein in one switching position the electrical circuit closed in the basic switching position is interrupted and in the further switching position a further circuit is closed. Preferably, the method is further developed according to the embodiments explained in connection with the ball joint according to the invention described here. Furthermore, the ball joint described here can be further developed according to the embodiments explained in connection with the method.

[0033] The invention is not limited to the specified combination of features of the independent claims or those dependent thereon. Furthermore, possibilities arise for combining individual features with one another, even if they emerge from the claims, the following description of preferred embodiments of the invention, or directly from the drawings. The reference of the claims to the drawings by the use of reference symbols is not intended to limit the scope of protection of the claims.

[0034] An advantageous embodiment of the invention, which is explained below, is illustrated in the drawings. It shows: Fig. 1 a sectional side view of a ball joint according to the invention; Fig. 2 schematically and exemplarily an arrangement of a circuit arrangement of a sensor device for wear detection in a bearing shell of the ball joint; Fig. 3 schematically and exemplarily an arrangement of the circuit arrangement in the joint housing of the ball joint; Fig. 4 schematically and exemplarily an arrangement of the circuit arrangement on a joint ball of the ball joint; Fig. 5 schematically and exemplarily a view of the circuit arrangement from above; Fig. 6 a sectional view along the line AA of the circuit arrangement according to Fig. 5; Fig. 7 schematically and exemplarily a view of a switching element and a circuit board, each from above; Fig. 8 schematically and exemplarily a plan view of a switching element according to a second embodiment; Fig. 9 schematically and exemplarily a plan view of a switching element according to a third embodiment; Fig. 10 schematically and exemplarily a plan view of a switching element according to a fourth embodiment.

[0035] Fig. 1 shows a sectional side view of a ball joint 10 according to the invention. In this exemplary embodiment, the ball joint 10 is designed as a ball and stud joint. The ball joint 10 has a joint housing 1. The joint housing 1 can, for example, be realized as a component of a chassis component. The joint housing 1 has a housing recess 3. In this exemplary embodiment, the housing recess 3 is essentially pot-like or cup-shaped. Furthermore, the ball joint 10 has an inner joint part. The inner joint part is designed here as a ball stud 2. Accordingly, the ball stud 2 has a joint ball 4 and a stud 5. The inner joint part or the ball stud 2 is movably mounted in the housing recess 3. A bearing shell 6 is arranged between an inner side of the housing recess 3 and the joint ball 4.

[0036] The joint housing 1 is secured against withdrawal from the housing recess 3 by a closure element. The pin 5 extends outward from the housing recess 3 through an opening 7 of the closure element. Furthermore, the ball joint 10 has a sealing bellows 8. The sealing bellows 8 rests on the one side against the joint housing 1 and on the other side against the pin 5.

[0037] According to this illustration, the ball joint 10 is rotationally symmetrical to a central longitudinal axis 9. The ball stud 2 is mounted in the bearing shell 6 so as to be pivotable relative to the central longitudinal axis 9 and / or around a center point of the joint ball 4.

[0038] In Fig. Figure 2 shows a schematic and exemplary arrangement of a circuit arrangement 11 of a sensor device for wear detection. The circuit arrangement 11 is arranged within the joint housing 1, here in the bearing shell 6 of the ball joint 10.

[0039] According to the Fig. In the embodiment shown in Figure 2, the circuit arrangement 11 is arranged on the inside of the bearing shell 6, so that the circuit arrangement 11 faces the joint ball 4. The circuit arrangement 11 of the sensor device is directly mechanically actuated by the joint ball 4 arranged within the joint housing 1.

[0040] The circuit arrangement 11 is wear-induced and can be transferred from a basic switching position, in which a circuit 21 of the circuit arrangement 11 is closed, into at least two further switching positions, wherein in one switching position the circuit 21 closed in the basic switching position is interrupted and in the further switching position a further circuit 22 is closed.

[0041] The representation in Fig. Figure 3 shows a schematic and exemplary arrangement of the circuit arrangement 11 in the joint housing 1 of the ball joint 10. The circuit arrangement 11 is arranged inside the joint housing 1. The circuit arrangement 11 of the sensor device is indirectly mechanically actuated by the joint ball 4 arranged within the joint housing 1.

[0042] Fig. Figure 4 shows a schematic and exemplary arrangement of the circuit arrangement 11 on the joint ball 4 of the ball joint 10. The arrangement of the circuit arrangement 11 is preferably provided in the region of the upper half of the joint ball 4. The circuit arrangement 11 of the sensor device is directly mechanically actuated by the joint ball 4 arranged within the joint housing 1.

[0043] The representation in Fig. Figure 5 shows a schematic and exemplary view of the circuit arrangement 11 arranged in the bearing shell 6 from above. Fig. 6 is a sectional view of the circuit arrangement 11 along the line AA according to Fig. 5 shown.

[0044] The circuit arrangement 11 comprises a substantially dome-shaped switching element 12 made of a spring-elastic material and a circuit board 13 or foil arranged opposite the switching element 12.

[0045] According to the illustrated embodiment, the switching element 12 is made of an electrically conductive material. Alternatively, the switching element 12 can have an electrically conductive coating. According to a further alternative, interconnected lines can be integrated into the switching element 12.

[0046] The circuit arrangement 11 has at least one connection point, at which the switching element 12 is electrically connected by at least one support element 14 to at least one contact surface 15, in particular embodied as a conductor track, on the circuit board 13 or film. Furthermore, the switching element 12 has a first contact element 16, which can be brought into contact with a first conductor track section 17 on the circuit board 13 or film. The at least one support element 14, which is electrically conductively connected to the at least one contact surface 15 on the circuit board 13 or film, can be connected to the first conductor track section 17, in particular by a soldering point.

[0047] A second contact element 18 of the switching element 12 can be brought into contact with a second conductor track section 19 on the circuit board 13 or film. The second conductor track section 19 is arranged substantially centrally below the switching element 12. The at least one contact surface 15, which is particularly designed as a conductor track, the first conductor track section 17, and the second conductor track section 19 are electrically insulated from one another.

[0048] The switching element 12 has an elastically deformable concave section 20, on which at least two support elements 14, 14A are arranged along its periphery. Fig. In the embodiment shown in Figure 5, a total of four support elements, three support elements 14 and one shortened support element 14A, are arranged along the periphery of the concave section 20. The first contact element 16 is designed as a shortened support element, so that the first contact element 16 has no contact with the first conductor track section 17 when the switching element 12 is unloaded. The concave section 20 forms the second contact element 18 of the switching element 12.

[0049] In its basic switching position, the switching element 12 is subjected to a force by the joint ball 4, so that the first contact element 16 is in contact with the first conductor track section 17 due to the elastic deformation of the switching element 12, while the second contact element 18 is spaced from the second conductor track section 19. The basic switching position represents the unworn state or the state of wear within a permissible tolerance range of the ball joint 10 or of the joint ball 4 and bearing switch 6. In the basic switching position, in which the circuit 21 of the circuit arrangement 11 is closed, a signal is generated indicating the correct functionality of the sensor device. For this purpose, a device 21A can be provided, which is integrated into the circuit 21 or connected to it.This makes it possible to detect a functional restriction, for example due to corrosion caused by contamination of the ball joint 10 or a functional failure of the sensor device, for example due to an interruption of an electrical connection.

[0050] In Fig. 7 shows a schematic and exemplary view of the switching element 12 and the circuit board 13, each from above. In the basic switching position, the switching element 12 is subjected to a force by the joint ball 4, so that the first contact element 16 is conductively connected to the first conductor track section 17 and the circuit 21 of the circuit arrangement 11 is closed. For this purpose, the switching element 12 is subjected to a force directed essentially perpendicular to the second contact element 18. The circuit arrangement 11 can be transferred from the basic switching position into at least two further switching positions due to wear.

[0051] Wear occurring on the joint ball 4 leads to an increase in bearing play. The switching element 12 moves from the basic switching position to a first switching position depending on the degree of wear on the joint ball 4. In doing so, the first contact element 16 lifts off the first conductor track section 17. The migration of the joint ball 4 out of the bearing leads to the lifting of the first contact element 16, which interrupts the electrical circuit 21 closed in the basic switching position. The lifting of the first contact element 16 is caused by the restoring force generated in the dome-shaped switching element 12 in the basic switching position. The wear-related undershoot of a limit value for the bearing play, which corresponds to the migration of the joint ball 4 out of the bearing, leads to the first contact element 16 moving away from the first conductor track section 17 as the switching element 12 springs back to its original shape.In this way, the circuit 21, which is closed in the basic switching position, can be interrupted in order to signal the wear of the ball joint 10, in particular due to the bearing play, to the outside.

[0052] In the second switching position of the switching element 12, a conductive contact is established between the second contact element 18 and the second conductor track section 19 on the circuit board 13 or the foil. This is caused by the wear of the bearing shell 6. The wear of the bearing shell 6 causes the joint ball 4 to be pressed into the bearing shell 6. As the wear of the bearing shell 6 increases, the joint ball 4 presses the dome-shaped switching element 12 or the concave section 20 in far enough that contact is made between the second contact element 18 and the second conductor track section 19. This allows the additional circuit 22 to be closed in order to signal the wear of the ball joint 10, in particular of the bearing shell 6, to the outside. For this purpose, a device 22A can be provided which is integrated into the circuit 22 or connected to it.

[0053] By interrupting the circuit 21 or closing the circuit 22, signals can be generated that can be transmitted to an evaluation device, so that a suitable indication of the existing wear condition can be output or read out. This is advantageous because it allows differentiation between the wear occurring on the joint ball 4 and the bearing shell 6.

[0054] The device 22A can, for example, enable the connection of a measuring device or the evaluation device.

[0055] The switching element 12 can have a force-displacement characteristic curve adapted to its positioning within the joint housing 1 in order to, on the one hand, specify the restoring force with which the dome-shaped switching element 12, pressed in by the joint ball 4, springs back to its initial position. On the other hand, the force to be applied by the joint ball 4, with which the second contact element 18 is pressed against the second conductor track section 19 due to wear, can be specified. Depending on the arrangement of the circuit arrangement 12 in the ball joint 10, the force-displacement characteristic curve is designed to take into account the location of the different mounting positions of the circuit arrangement 11 in the ball joint 10. In addition, the design of the force-displacement characteristic curve enables the definition of a tolerance range for a permissible wear state of the joint ball 4 and / or bearing shell 6.

[0056] In the Fig. 8 to 10 show further embodiments of switching elements 23 to 25.

[0057] The Fig. The switching element 23 shown in Figure 8 differs from the embodiment of the switching element 12 by a circular recess in the center of the concave section 20.

[0058] The Fig. The switching element 24 shown in Figure 9 differs from the embodiment of the switching element 12 by its essentially circular shape and the number of connection points 26, which are electrically connected to at least one contact surface 15, corresponding to the support points 14, as well as the one connection point 26A, which corresponds in function to the shortened support element 14A, which serves as the first contact element 16. A centrally arranged convex section 27 in the concave section 20 of the switching element 24 forms the second contact element 18.

[0059] The Fig.The switching element 25 shown in Figure 10 differs from the embodiment of the switching element 12 in its outer cuboid contour. Formed in the corner regions are three connection points 28, which, corresponding to the support points 14, are electrically connected to at least one contact surface 15, as well as a fourth connection point 28A, which corresponds in function to the shortened support element 14A, which serves as the first contact element 16. In the center, the switching element 24 has a concave section 29, which forms the second contact element 18.

[0060] To design the force-displacement characteristic curve and to adapt it to the respective positioning within the ball joint 10, the shape, material thickness, and / or size of the switching element 12, 23, 24, 25 can be adjusted. The dimensioning of the concave section 20, 29 is the key factor influencing the force-displacement characteristic curve. Reference symbol 1 joint housing 2 ball studs 3 Housing recess 4 joint ball 5 cones 6 bearing shell 7 Opening 8 Sealing bellows 9 Central longitudinal axis 10 ball joint 11 Circuit arrangement 12 switching element 13 circuit boards 14 Support element 14 Shortened support element 15 Contact surface 16 First contact element 17 First conductor track section 18 Second contact element 19 Second conductor section 20 Concave section 21 Circuit 21A device 22 circuit 22A device 23 Switching element 24 switching element 25 switching element 26 Junction 26A junction 27 Convex section 28 Junction 28A junction 29 Concave section QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2008 041 050 A1

[0004] DE 10 2005 030 971 A1

[0005] DE 100 09 054 C2

[0006]

Claims

[1] Ball joint (10) for a motor vehicle, in particular for a chassis of the motor vehicle, comprising: - a joint housing (1) having a joint opening in which a bearing shell (6) is arranged, - a ball pin (2) having a joint ball (4) and a pin (5), which is mounted with its joint ball (4) in the bearing shell (6) in an articulated manner and which projects with its pin (5) through the joint opening out of the joint housing (1), and - a sensor device for wear detection, characterized byin that the sensor device has a circuit arrangement (11) which is mechanically actuated by the joint ball (4) and which is arranged within the joint housing (1), wherein the circuit arrangement (11) can be transferred, due to wear, from a basic switching position in which an electrical circuit (21) of the circuit arrangement (11) is closed, into at least two further switching positions, wherein in one switching position the electrical circuit (21) which is closed in the basic switching position is interrupted and in the further switching position a further circuit (22) is closed. [2] Ball joint (10) according to claim 1, characterized by that the circuit arrangement (11) comprises a substantially dome-shaped switching element (12) made of a spring-elastic material and a circuit board (13) or film arranged opposite the switching element (12). [3] Ball joint (10) according to claim 2, characterized bythat the switching element (12, 23, 24, 25) consists of an electrically conductive material, has an electrically conductive coating or that interconnected lines are integrated into the switching element (12, 23, 24, 25). [4] Ball joint (10) according to one of claims 2 or 3, characterized by in that the circuit arrangement (11) has at least one connection point through which the switching element is electrically conductively connected to at least one contact surface (15) on the circuit board (13) or film, and a first contact element (16) which can be brought into contact with a first conductor track section (17) on the circuit board (13) or film, and a second contact element (18) which can be brought into contact with a second conductor track section (19) on the circuit board (13) or film, wherein the at least one contact surface (15), the first conductor track section (17) and the second conductor track section (19) are electrically insulated from one another. [5] Ball joint (10) according to claim 4, characterized by that the switching element (12, 23, 24, 25) is subjected to a force by the joint ball (4) in the basic switching position, so that the first contact element (16) is in contact with the first conductor track section (17) due to the elastic deformation of the switching element (12, 23, 24, 25) and the second contact element (18) is spaced from the second conductor track section (19). [6] Ball joint (10) according to claim 4 or 5, characterized by that the switching element (12, 23, 24, 25) changes from the basic switching position to the first switching position depending on the degree of wear of the joint ball (4) and / or that the switching element (12, 23, 24, 25) changes from the basic switching position to the second switching position depending on the degree of wear of the bearing shell (6). [7] Ball joint (10) according to one of claims 4 to 6, characterized bythat the switching element (12, 23, 24, 25) has an elastically deformable concave section (20, 29) on which at least two support elements (14, 14A; 26, 26A; 28, 28A) are arranged along its periphery. [8] Ball joint (10) according to claim 7, characterized by that at least one of the at least two support elements (14, 26, 28) is electrically conductively connected to the at least one contact surface (15) on the circuit board (13) or the film, wherein the further support element (14A, 26A, 28A) forms the first contact element (16). [9] Ball joint (10) according to claim 7 or 8, characterized by that the concave section (20, 29) of the switching element (12, 23, 25) forms the second contact element (18). [10] Ball joint (10) according to claim 7 or 8, characterized by that the switching element (25) has a convex section (27) formed centrally in the concave section (20), which forms the second contact element (18). [11] Ball joint (10) according to one of claims 1 to 10, characterized by that the circuit arrangement (11) is arranged on the bearing shell (6), the joint ball (4) or inside the joint housing (1). [12] Ball joint (10) according to one of claims 2 to 11, characterized by that the switching element (12, 23, 24, 25) has a force-displacement characteristic curve which is dimensioned depending on the arrangement of the switching arrangement (11) in the ball joint (10). [13] Ball joint (10) according to claim 12, characterized by that the shape, material thickness and / or size of the switching element (12, 23, 24, 25) can be adapted to design the force-displacement characteristic curve. [14] Ball joint (10) according to one of claims 1 to 13, characterized by that the switching element (12, 23, 24, 25) is coated with a flexible contact and protective layer on its surface in contact with the joint ball (4). [15] Method for producing a ball joint (10) according to one of the preceding claims, with a joint housing (1) having a joint opening, in which a bearing shell (6) is arranged, a ball pin (2) having a joint ball (4) and a pin (5), which is mounted with its joint ball (4) in the bearing shell (6) in an articulated manner and projects with its pin (5) through the joint opening out of the joint housing (1), and is designed with a sensor device for wear detection, characterized by in that the sensor device has a circuit arrangement (11) which is mechanically actuated by the joint ball (4) and which is arranged within the joint housing (1), wherein the circuit arrangement (11) is transferred, due to wear, from a basic switching position in which an electrical circuit (21) of the circuit arrangement (11) is closed, into at least two further switching positions.

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