Ball joint for wheel suspension

Abstract

A ball joint (10) for a wheel suspension of a motor vehicle has a housing (16) and a ball stud (12) which is received in the housing (16) and has a spherical section (14). A bearing shell (20) is arranged between the spherical section (14) and an inner wall (34) of the housing (16). Furthermore, a cover (22) is provided, which is separate from the bearing shell (20), is fixedly connected to the housing (16), and has a support surface (48) for the bearing shell (20) on one side and a receptacle (54) for a sensor unit (26) on the opposite side, within which a sensor unit (26) is detachably mounted.

Description

[0001] The invention relates to a ball joint for a wheel suspension of a motor vehicle, comprising a housing, a ball stud which is received in the housing and has a spherical section, wherein a bearing shell is arranged between the spherical section and an inner wall of the housing, and wherein a cover is provided which is designed separately from the bearing shell and is firmly connected to the housing.

[0002] Such ball joints for the wheel suspensions of motor vehicles are known.

[0003] In motor vehicles, sensors are used to control or regulate chassis and vehicle safety systems that represent the kinematic and dynamic behavior of the vehicle. For example, sensor information is needed to control dynamic headlight range adjustment based on kinematic information about the inclination to the road surface.

[0004] It is also known to integrate such sensors into ball joints. However, this usually requires compromises that lead to reduced bearing quality and / or decreased sensor accuracy.

[0005] The object of the invention is to provide a ball joint that has low tolerances and into which a sensor with high accuracy can be reliably integrated.

[0006] The problem is solved by a ball joint for a motor vehicle's wheel suspension, comprising a housing, a ball stud which is received in the housing and has a spherical section. A bearing shell is arranged between the spherical section and an inner wall of the housing. Furthermore, a cover is provided, which is separate from the bearing shell, is fixedly connected to the housing, and has a support surface for the bearing shell on one side and a receptacle for a sensor unit on the opposite side, within which the sensor unit is detachably mounted. The receptacle for a sensor unit is hereinafter referred to as the sensor receptacle.

[0007] It was recognized according to the invention that by designing the bearing shell and the cover separately, these two components can be manufactured with properties specifically adapted to their requirements and with tight tolerances, thus providing their function particularly effectively. Furthermore, the bearing shell can be pre-tensioned more effectively using the separate cover, ensuring a defined arrangement of the components forming the joint relative to each other with minimal effort. This results in a consistently high-quality joint. The sensor receptacle integrated into the cover also ensures that a sensor unit can be precisely positioned with minimal effort and thus provides consistently accurate measured values ​​as part of a sensor. The cover, as a stable component, prevents relative displacement and protects the sensor from mechanical damage.Furthermore, the ball joint is formed by a small number of components and therefore offers advantages in manufacturing and logistics.

[0008] In one embodiment, the bearing shell and the cover are made of different materials that can be optimally adapted to the different requirements.

[0009] The cover can be made of metal, making it particularly robust and ensuring a consistently defined support surface for the bearing shell. Furthermore, the metal sensor mount guarantees excellent protection against damage.

[0010] With a metal lid, the sensor mount can be integrated as a single piece with the lid. This ensures a defined arrangement of the sensor mount and thus the sensor unit. Furthermore, the number of components in the ball joint is further reduced.

[0011] In an alternative embodiment, the cover is a composite component comprising a metal ring for attachment to the housing and a plastic body that provides the support surface and sensor receptacle. This design allows for easy manufacturing of the cover while simultaneously making it particularly robust.

[0012] Furthermore, it may be provided that the sensor mount has a circumferentially closed wall, which makes the sensor mount particularly robust and protects the sensor unit particularly well.

[0013] According to one embodiment, the sensor receptacle has a groove on its outer surface into which a mounting clip engages, which is mounted on the sensor unit. Thus, the sensor unit is reliably attached to the cover and precisely aligned with it.

[0014] According to a further embodiment, a sensor target is accommodated in the spherical section, and the sensor unit includes a position sensor. The position sensor is configured to detect the relative position of the sensor target and thus the orientation of the ball stud relative to the housing.

[0015] In this case, the sensor target can be a permanent magnet and the position sensor a Hall sensor, which allows the relative position to be determined particularly accurately.

[0016] Additionally or alternatively, the sensor target can be housed in a plug that is pressed into the ball stud. This ensures that the sensor target is effectively and securely fixed within the ball stud.

[0017] The plug can be connected to the ball stud by means of a force-fit and / or a positive-locking connection to ensure a permanent connection and precise arrangement.

[0018] Furthermore, the plug can be provided with at least one vent groove. This prevents a pressure chamber from forming between the plug and the ball stud when the plug is pressed in, which would otherwise subject the plug to a force pushing out of the ball stud.

[0019] According to one aspect, the sensor unit contains an acceleration sensor to detect the acceleration of the ball joint or the vehicle. This data can then be used to control or regulate the vehicle's chassis and / or safety systems.

[0020] Another aspect is that the sensor unit is equipped with one of several different types of printed circuit boards, making it particularly compact. Furthermore, this modular design allows the sensor unit to be easily adapted to different requirements or applications.

[0021] In one embodiment, a flexible conductor track is provided that extends from one side of the circuit board to the opposite side. This allows sensors to be attached to the circuit board on different sides and connected to it for signal transmission.

[0022] Additionally or alternatively, the circuit board can be provided with geometric features for unambiguous positioning in order to ensure a defined orientation of the circuit board and the one or more sensors arranged on it with minimal effort.

[0023] Furthermore, the circuit board can be potted inside the sensor unit, which provides it with particularly good protection and a defined arrangement.

[0024] In another embodiment, a sealing ring is arranged between the sensor unit and the sensor mount to effectively protect the sensor unit from environmental influences.

[0025] Furthermore, the bearing shell can be designed to be ring-shaped and have a contact arc length corresponding to the sliding arc length of the ball section at maximum tilt angle. This results in a low bearing shell height and therefore a compact design.

[0026] The spherical section can have a recess whose central axis coincides with the central axis of a shaft of the ball stud, with the edge of the recess not overlapping the bearing race when the ball stud is at maximum deflection. This prevents contact between the edge of the recess and the bearing race, thus avoiding any potential damage to the ball bearing. Furthermore, it ensures that a sensor target or its mounting within the recess cannot come into contact with the bearing race and be displaced. The coaxial arrangement of the recess relative to the shaft of the ball stud offers the advantage of allowing the sensor target to be positioned within the spherical section with minimal effort, enabling precise measurement of the ball stud's deflection.

[0027] Further advantages and features will become apparent from the following description and the accompanying drawings. These show: - Fig. 1 in a schematic sectional view a ball joint according to the invention, - Fig. 2 in a perspective view, a cover of the ball joint made of Fig. 1, - Fig. 3 in a perspective view a mounting bracket of the ball joint made of Fig. 1, - Fig. 4 in a side view the ball joint Fig. 1 without mounting bracket, - Fig. 5 in a detailed view the ball joint Fig. 4, - Fig. 6 in a side view the ball joint Fig. 1, - Fig. 7 in a perspective view a circuit board of the ball joint made of Fig. 1, - Fig. 8 in a side view the circuit board Fig. 7, - Fig. 9 in a perspective view a circuit board of the ball joint made of Fig. 1 according to one variant, - Fig. 10 in a side view the circuit board made of Fig. 9 in an unfolded state without a sensor, - Fig. 11 in a sectional view the ball joint Fig. 1 in a maximally deflected state, with the sensor unit not shown, - Fig. 12 in a sectional view a ball stud of the ball joint made of Fig. 1 with a sensor target mounted in a plug in side view, - Fig. 13 in a perspective view of the plugs made of Fig. 12, - Fig. 14 in a sectional view the plug with recorded sensor target from Fig. 12, - Fig. 15 in a bottom view the plug with recorded sensor target from Fig. 12, - Fig. 16 in a bottom view the plug with recorded sensor target from Fig. 12 according to one variant, - Fig. 17 in a sectional view the ball stud of the ball joint Fig. 1 according to one variant, - Fig. 18 in a top view the ball stud from Fig. 17, - Fig. 19 in a sectional view the ball stud of the ball joint Fig. 1 according to another variant, - Fig. 20 in a top view the ball stud from Fig. 19, - Fig. 21 in a schematic sectional view a ball joint according to the invention with a cover according to a further embodiment, - Fig. 22 in a perspective view the lid from Fig. 21, - Fig. 23 in a sectional view the lid from Fig. 21, - Fig. 24 in a schematic sectional view a ball joint according to the invention with a cover according to a further embodiment in a partially assembled state, wherein the sensor unit is not shown, - Fig. 25 in a schematic sectional view the ball joint made of Fig. 24 in the assembled state, with the sensor unit not shown, - Fig. 26 in a perspective view another embodiment of the ball joint made of Fig. 1, where only the lid and the sensor unit are shown, which are connected to each other by means of a spring clip, - Fig. 27 in a perspective view the spring clip from Fig. 26, - Fig. 28 in a perspective view the lid from Fig. 26, and - Fig. 29 in a sectional view the lid from Fig. 26.

[0028] The detailed description below, in conjunction with the accompanying drawings, in which identical numbers refer to identical elements, is intended to describe various embodiments of the disclosed subject matter and is not meant to represent the only embodiments. Each embodiment described in this disclosure serves only as an example or illustration and should not be construed as preferable or advantageous over other embodiments.

[0029] All features disclosed below with reference to the exemplary embodiments and / or the accompanying figures can be combined alone or in any subcombination with features of the aspects of the present disclosure, including features of preferred embodiments, provided that the resulting combination of features is meaningful to a person skilled in the art.

[0030] In Fig. Figure 1 shows a ball joint 10 for a wheel suspension of a motor vehicle.

[0031] The ball joint 10 has a ball stud 12 with a ball section 14 and a housing 16 with a through hole 18 in which the ball section 14 is received and pivotably mounted via a bearing shell 20.

[0032] Furthermore, the ball joint 10 has a cover 22 which closes the through hole 18 opposite to a shaft 24 of the ball stud 12, and a sensor unit 26 which is detachably attached to the cover 22 by means of a fastening element 28.

[0033] Housing 16 is part of a chassis component of the wheel suspensions.

[0034] The through-hole 18 extends in axial direction A from a first axial end 30 to a second axial end 32 and has an inner wall 34 which forms a ball receptacle 36 for the ball section 14.

[0035] The bearing shell 20 is designed separately from the cover 22 and is made, for example, of a friction-optimized plastic.

[0036] In the illustrated embodiment, the lid 22 is designed as a single piece and is made of metal.

[0037] In an alternative embodiment, the lid 22 can be made of a plastic, for example a fiber-reinforced plastic.

[0038] The bearing shell 20 is arranged between the inner wall 34 and the spherical section 14, which rests against the bearing shell 20 via a spherical section 40 of the spherical section 14 encompassing the equator 38 of the spherical section 14.

[0039] Furthermore, the bearing shell 20 can be designed in a ring shape and / or have axial slots to facilitate axial insertion of the ball section 14 into the bearing shell 20.

[0040] At the second axial end 32, the housing 16 has a chamfer where the shaft 24 is in a state of maximum deflection of the ball stud 12 (see Fig. 11) is located and thus forms a stop for the ball stud 12.

[0041] At the first axial end 30, the housing 16 has an annular recess 42 in the form of a circumferential groove, in which an annular collar 44 (see Fig. 2) of the lid 22 is arranged.

[0042] In this context, the cover 22 has a sleeve-shaped axial section 46 with a support surface 48 against which the bearing shell 20 rests in axial direction A.

[0043] In the present embodiment, the support surface 48 is arranged at one axial end of the sleeve-shaped axial section 46 opposite the bearing shell 20.

[0044] To attach the cover 22 to the housing 16, during assembly the ball stud 12 with the bearing shell 20 is first inserted into the ball receptacle 36 and then the cover 22 with the annular collar 44 and the sleeve-shaped axial section 46 is inserted into the through hole 18.

[0045] Subsequently, a housing edge 50 at the first axial end 30 is formed by a plastic forming process, for example by rolling or flanging, in order to form the annular recess 42 and thus to fix the cover 22 to the housing 16 in a form-fitting manner.

[0046] In this case, the ball joint 10 is designed such that the cover 22 rests on the bearing shell 20 via the support surface 48 and preloads the bearing shell in axial direction A against an axial stop 52, which is axially adjacent to the inner wall 34.

[0047] The cover 22 has a sensor receptacle 54 on the side opposite the sleeve-shaped axial section 46, in which the sensor unit 26 is received section by section and via which the sensor unit 26 is attached to the cover 22.

[0048] The sensor mount 54 has a circumferential U (see Fig. 2) closed circumferential wall 56 with a radial outer surface 58.

[0049] On the outer side 58, the sensor receptacle 54 has two grooves 60 offset from each other by 180° in the circumferential direction U, into which the fastening element 28 engages to fix the sensor unit 26 to the cover 22.

[0050] In the present embodiment, the fastening element 28 is a fastening clip 62 (see Fig. 3).

[0051] In this context, the sensor unit 26 has a sensor housing 64 with retaining sections 66 designed to complement the grooves 60 (see Fig. 4 and Fig. 5), via which the fastening element 28 positively engages with the grooves 60 and the sensor housing 64 (see Fig. 6).

[0052] This ensures that the sensor unit 26 is positioned in a defined orientation relative to the cover 22 when the sensor housing 64 is attached to the circumferential wall 56 via the groove 60 using the fastening element 28.

[0053] Additionally or alternatively, the sensor mount 54 can have one or more positioning structures 68 (see Fig. 22 and Fig. 23), which interlock with complementary positioning structures on the sensor housing 64 to ensure a defined arrangement of the sensor unit 26 relative to the cover 22.

[0054] The sensor unit 26 (see Fig. 1) has an internal sensor chamber 70 in which a circuit board 72 is arranged.

[0055] The circuit board 72 is connected to a terminal 76 of the sensor unit 26 via connection pins 74 which are embedded in the sensor housing 64, transmitting signals.

[0056] In the present embodiment, the sensor unit 26 has a position sensor 78 and an acceleration sensor 80.

[0057] In principle, the sensor unit 26 can have one or more sensors of any kind, in particular a position sensor 78 and / or an acceleration sensor 80.

[0058] The position sensor 78 is mounted on the circuit board 72 opposite the spherical section 14, while the acceleration sensor 80 is mounted axially opposite the position sensor 78 on the circuit board 72. In other words, the position sensor 78 and the acceleration sensor 80 are arranged on opposite sides of the circuit board 72 (see Fig. 8).

[0059] The circuit board 72 has geometric features 82 (see Fig. 7), for example in the form of positioning recesses into which complementary geometric features of the sensor housing 64, for example in the form of positioning lugs, engage in order to align the circuit board 72 and thus the sensors 78, 80 in a defined manner relative to the sensor housing 64, in particular uniquely.

[0060] Instead of the ones in the Fig. 7 and Fig. The simple printed circuit board shown in section 8 can be a flexible printed circuit board (see [reference]). Fig. 10) which is folded accordingly to arrange the sensors 78, 80 on opposite sides of the folded circuit board 72 (see Fig. 9).

[0061] In this case, one side of the circuit board 72 is connected to the opposite side of the folded circuit board 72 by a flexible conductor track 84.

[0062] Of course, in an alternative embodiment, the sensor unit 26 can have one or more arbitrarily designed circuit boards 72 for the one or more sensors 78, 80.

[0063] In the illustrated embodiment, the circuit board 72 with the sensors 78, 80 is encapsulated in the sensor chamber 70 by means of a casting material 86 (see Fig. 1).

[0064] Furthermore, a plastic closure cap 88 is provided, which closes the sensor chamber 70.

[0065] Furthermore, a sealing ring 90 is arranged between the circumferential wall 56 and the sensor housing 64 to seal the sensor chamber 70 against environmental influences.

[0066] The sealing ring 90 is optional and can therefore be omitted in other embodiments.

[0067] The position sensor 78 is functionally coupled to a sensor target 92, which is arranged in a recess 96 of the spherical section 14 by means of a plug 94 (see Fig. 11).

[0068] The recess 96 is provided here in a pole section 98 of the spherical section 14 arranged opposite to the shaft 24.

[0069] For example, the position sensor 78 is a Hall sensor and the sensor target 92 is a permanent magnet.

[0070] The cover 22 or the sleeve-shaped axial section 46 form a joint chamber 100 in which the pole section 98 of the spherical section 14 is received.

[0071] In the present embodiment, the pole section 98 does not make contact with the cover 22, the housing 16 or the bearing shell 20 in any position of the ball joint 10 or when the ball stud 12 is not deflected.

[0072] Furthermore, the edge 102 of the recess 96 in the maximally deflected position (see Fig. 11) no contact with the bearing shell 20.

[0073] The bearing shell 20 can have a height H that is less than or equal to the radius R of the spherical segment 14.

[0074] In an alternative embodiment, the rim 102 and / or the plug 94 can abut the bearing shell 20 and / or the cover 22 in at least some of the positions of the ball joint 10.

[0075] The recess 96 is formed by a blind hole (see Fig. 12), whose central axis M coincides with the central axis N of the shaft 24. In other words, the recess is designed coaxially with the shaft 24.

[0076] The plug 94 is made of plastic, for example an elastic plastic.

[0077] Furthermore, the plug 94 has cylindrical axial sections 104 which fit tightly and securely against the inner wall of the blind hole, as well as a cap-shaped section 106 which covers the recess 96 and rests against a recess edge 108 in axial direction A.

[0078] The cylindrical axial sections 104 have at least one venting groove 110 (see Fig. 13), which extends in axial direction A through the axial sections 104.

[0079] The sensor target 92 is in a chamber 112 (see Fig. 14) is positively fitted inside the plug 94.

[0080] The plug 94 can be made in one piece.

[0081] For manufacturing, the sensor target 92 can be overmolded with the plug 94, either completely or at least section by section.

[0082] In one variant, chamber 112 is open in the opposite direction to the cap-shaped section 106 (see Fig. 11).

[0083] In an alternative variant, a retaining web 114 extends in a radial direction (see Fig. 15) adjacent to the sensor target 92 or the chamber 112, in order to hold the sensor target 92 precisely in the plug 94.

[0084] In another variant (see Fig. 16) Two support bridges 114 extend crosswise and adjacent to the sensor target 92 and the chamber 112, respectively.

[0085] The plug 94 with the sensor target 92 is pressed into the recess 96 and is thus securely fastened in it by force and form.

[0086] The recess edge 108 forms an axial stop for the cap-shaped section 106, which ensures a defined arrangement of the sensor target 92 in the recess 96.

[0087] To further secure the sensor target 92, the plug 94 can be connected via a positive locking connection 116 (see Fig. 17 to 20) are connected to the sphere segment 14.

[0088] In the Fig. 17 and Fig. In the embodiment shown in 18, the positive locking connection 116 is formed by three extensions 118 which project radially into the recess 96.

[0089] In the Fig. 19 and Fig. In the embodiment shown in Figure 20, the positive locking connection 116 is an edge 120 circumferentially U, which projects radially into the recess 96.

[0090] In principle, the positive locking connection 116 can be designed in any way, in particular with any number of extensions 118 and / or circumferential edges 120.

[0091] In this way, the sensor target 92 is defined in all embodiments and fixed in the spherical section 14 and arranged in such a way as to allow the deflection of the ball stud 12 to be determined permanently and precisely by means of the position sensor 78.

[0092] Based on the Fig. Sections 21 to 23 now describe a ball joint 10 according to a further embodiment. The same reference numerals are used for the components known from the above embodiment, and reference is made to the preceding explanations in this respect.

[0093] Unlike in the Fig. In the embodiment shown in Figure 1, the cover 22 is a composite component formed from a metal ring 122 and a plastic body 124.

[0094] The plastic body 124 can be made of a fiber-reinforced plastic.

[0095] For example, the plastic body 124 is injection-molded onto the metal ring 122.

[0096] In an alternative embodiment (see Fig. 24 and Fig. 25) The metal ring 122 and the plastic body 124 are fitted together during assembly to form the lid 22.

[0097] A ring-shaped sealing element 126 is arranged between the metal rings 122 and the plastic body 124 to ensure a particularly high level of sealing.

[0098] Based on the Fig. Sections 26 to 29 now describe a ball joint 10 according to a further embodiment. The same reference numerals are used for the components known from the above embodiments, and reference is made to the preceding explanations in this respect.

[0099] Unlike in the Fig. In the embodiment shown in Figure 1, the sensor unit 26 is attached to the cover 22 by means of a fastening element 28 in the form of a spring clip 128.

[0100] The spring clip 128 has lower clamping sections 130 assigned to the cover 22, which engage positively in groove 60 on the outside 58 of the sensor receptacle 54, and upper clamping sections 132 assigned to the sensor unit 26, which bear against the sensor housing 64 in axial direction A and together with the lower clamping sections 130 pre-tension or clamp the sensor unit 26 against the cover 22 in axial direction A.

[0101] To ensure a particularly high clamping effect, the cover 22 has a collar 136 at its axial end 134 facing the sensor unit 26, which circumferentially extends in section U (see Fig. 28), which extends in axial direction A to the grooves 60 (see Fig. 29) and thus forms or transitions into an axial side wall 138 of the groove 60.

[0102] In the fastening position, the lower clamping sections 130 lie axially against the axial side wall 138 and thus against the collar 136 under tension.

[0103] Naturally, the collar 136 can extend over one or more arbitrary sections in circumferential view U, for example completely.

[0104] Furthermore, the collar 136 can be arranged axially spaced from the axial end 134 facing the sensor unit 26 on the outside 58 of the sensor receptacle 54.

[0105] Furthermore, the spring clip 128 can have lower clamping sections 130 which are axially tensioned outside the groove 60 against the collar 136 and pre-tension or clamp the sensor unit 26 against the cover 22 in axial direction A.

[0106] The groove 60 and / or the collar 136 and the spring clip 128 are designed, for example, to be complementary in such a way that the sensor unit 26 is arranged in a defined position or orientation relative to the cover 22 when the sensor housing 64 is attached to the circumferential wall 56 by means of the fastening element 28 via the groove 60 and / or the collar 136.

[0107] In all embodiments, a ball joint 10 is provided in this way, which has low tolerances and into which at least one sensor with high accuracy can be reliably integrated.

[0108] Furthermore, the ball joint 10 is designed in such a way that it can be manufactured with minimal effort.

[0109] The cover 22 is designed to be multifunctional and fulfills several tasks. Firstly, it axially supports the bearing shell 20 near the ball section 14, thus minimizing settling of the bearing under operating load and ensuring a long service life. Furthermore, the cover 22 is connected to the housing 16 by a plastic forming process, preventing settling effects and ensuring a permanently tight seal. Additionally, the cover 22 forms a robust sensor receptacle 54 in which the sensors 78 and 80 are protected from external influences. The circumferential wall 56 ensures a stable and defined mounting.

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