Switch assembly and steering device for a motor vehicle, and motor vehicle

Abstract

The invention relates to a switch assembly (10) for a motor vehicle, comprising at least one switch element (12) and an electrically conductive discharge element (16), wherein the discharge element (16) is arranged in the surroundings of the switch element (12) and is designed to discharge an electrical charge excess from the surroundings of the switch element (12) to a vehicle mass of the motor vehicle in a controlled manner. According to the invention, the switch element (12) has a rotatable operating section (32) with at least one axis of rotation (r), wherein the discharge element (16) has at least one needle-shaped antenna section (18) which extends along the main extension direction (26) of the discharge element substantially perpendicularly in relation to the at least one axis of rotation (r). Alternatively or additionally, the discharge element (16) has, according to the invention, a discharge section (20) which can be directly electrically conductively connected to the vehicle mass of the motor vehicle in order to discharge the electrical charge excess to the vehicle mass of the motor vehicle.

Description

[0001] Switch arrangement and steering device for a motor vehicle and motor vehicle

[0002] The invention relates to a switch arrangement for a motor vehicle with at least one switch element and an electrically conductive discharge element, which is arranged in the vicinity of the switch element and is designed to discharge an excess electrical charge from the vicinity of the switch element to a vehicle mass of the motor vehicle in a controlled manner. A further aspect of the invention relates to a steering device for a motor vehicle, comprising a steering wheel and a steering shaft or steering column, wherein the steering device comprises the switch arrangement according to the invention. A further aspect of the invention relates to a motor vehicle with such a steering device. The "surroundings" of the switch element in the context of the present disclosure refers in particular to the area within a few millimeters, in particular the area within a few millimeters to a few centimeters, around the switch element.

[0003] Modern motor vehicles generally have a plurality of switch arrangements, which usually comprise a plurality of switch elements. Such a switch element can be designed to be operated by a user of the motor vehicle in order to perform a function assigned to the switch element in the motor vehicle. Such switch elements can be designed, for example, as push buttons and / or rotary switches and / or toggle switches. Such switch elements can alternatively or additionally have roller-shaped or rotatable operating sections, wherein such an operating section can be rotated, turned or rolled about a rotation axis that usually runs centrally along a longitudinal direction of the operating section in order to perform a desired operating action. Such switch elements are also known as "scroll and / or tip wheels".

[0004] With the increasing number of assistance systems in modern motor vehicles, the number of input options, input devices, or switch elements that can be assigned to the operation of the assistance systems or individual functions of these systems is also increasing. In order to make such systems particularly easy to operate, the corresponding switch elements are sometimes integrated directly into the steering wheel of such a motor vehicle as steering wheel switches. This means they are always within the user's immediate reach and can be operated blindly. The switch elements can be arranged in the steering wheel in such a way that a user who is gripping the steering wheel as intended can easily reach and conveniently operate the switch elements with their fingers or thumbs. This applies, for example, to switch elements that can be used to set a cruise control or to select a highly automated driving mode.

[0005] Due to space constraints and functional interrelationships, sensitive electronic components are often located in the immediate vicinity of the described switch elements. These components can be, for example, printed circuit boards (PCBs) or the electronic components arranged on such PCBs, such as sensors, particularly optical sensors. Sometimes, capacitive switches can also be arranged near such switch elements. Capacitive switches are known to function in such a way that an operator action is detected via a change in the electric field near the capacitive switches.

[0006] Due to the sensitivity of the described electronic components and / or the described capacitive control surfaces, it is necessary to protect these and other components in the vicinity of the described switch elements from unwanted electrical discharges and the associated current peaks. In particular, electrostatic discharge (ESD) on the described sensitive electronics should be prevented as much as possible. Such an electrostatic discharge can occur when the user of the motor vehicle brings their hand or a finger of their hand close to a switch element to operate it. If the finger and the switch element have different electrical potentials, a charge exchange inevitably occurs between the finger and the switch element. This usually occurs through an electrical current flow.This manifests itself in the well-known phenomenon of the user "getting a shock." The charge exchange can occur through air or through direct physical contact between the user's hand or finger and the switch element. The resulting high voltages can damage or even destroy sensitive electronic components.

[0007] EP 2 051 267 A1 discloses a so-called ESD protection device for electrical switching devices in motor vehicles. This device features electrical discharge elements that absorb the excess charge generated when the switching device is operated and conduct it away from sensitive electronic components. EP 2 051 267 A1 only shows a switching device designed in the form of a steering column lever.

[0008] In this context, DE 10 2011 008 742 A1 describes a push-button switch, i.e., a switch or switch element whose position can be changed translationally along an operating axis. The excess charge is diverted to a carrier plate by the discharge element.

[0009] According to known methods, the excess electrical charge is dissipated via additional electrical or mechanical components, such as ohmic resistors or mechanical labyrinths in which the charge is balanced. The use of additional cable harnesses is also known. These known solutions impair the efficiency of the dissipation and sometimes require a lot of space, which is often unavailable, especially in the steering wheel area of ​​a motor vehicle.

[0010] An object of the present invention is to provide a reliable and space-saving ESD protection device for a switch element with a rotatable operating section.

[0011] The problem is solved by the subject matter of the independent patent claims. Advantageous developments of the invention are described by the dependent patent claims, the following description, and the figures.

[0012] The invention is based on the realization that the known discharge elements cannot be transferred to switch elements with rotating operating sections due to their complex geometry. Rather, the complex movement geometry of the rotating operating sections results in entirely new requirements for the design and arrangement of ESD protection devices.

[0013] The invention therefore provides a switch arrangement for a motor vehicle, which comprises at least one switch element and an electrically conductive discharge element, wherein the discharge element is arranged in the vicinity of the switch element and is designed to discharge an excess electrical charge from the vicinity of the switch element to a vehicle ground of the motor vehicle in a controlled manner. The vehicle ground is preferably formed by a vehicle body or a vehicle chassis. In the context of the present disclosure, "vehicle ground" refers to ground in the electrical sense, in particular the reference potential of the electrical system. The vehicle ground therefore refers to the electrically conductive body of the motor vehicle, to which the electrical potential "0" is assigned.

[0014] The switch element according to the invention has a rotatable operating section with at least one rotation axis. The rotation axis can be arranged centrally or eccentrically within the rotatable operating section. If the rotatable operating section is elongated, the rotation axis preferably runs along a main extension direction of the operating section. In other words, the switch element can comprise a roller switch and / or a rocker switch or be designed as such.

[0015] According to the invention, the discharge element is arranged relative to the operating section in such a way that an excess electrical charge from the rotatable operating section or its surroundings can be discharged to the vehicle's ground. Such an excess electrical charge typically results from an electrostatic charge on the components and / or a user. If the user touches the components, the charge must be discharged to ground to prevent damage to electronic components, for example.

[0016] In one embodiment of the invention, the electrically conductive discharge element has at least one or more needle-shaped antenna sections or pins, which extend along its main direction of extension substantially perpendicular to the at least one axis of rotation. For the purposes of this invention, a needle-shaped antenna section is understood to be a flat or thin and elongated element with a round, rectangular, or square cross-section, which is at least part of an antenna or an antenna section. In other words, the discharge element according to the invention has at least one antenna section extending perpendicular to the axis of rotation, which is arranged in the vicinity of the rotatable operating section. The antenna section is designed to conduct an excess electrical charge in a controlled manner away from the rotatable operating section to the vehicle mass of the motor vehicle.In other words, the antenna section is arranged or positioned relative to the operating section in such a way that it represents the closest dissipation path for the excess charge. Preferably, the antenna section is formed from or comprises a material that has a reduced impedance with respect to ground compared to other components arranged in the vicinity.

[0017] The described geometry between the operating section and the antenna section results in greater spatial flexibility with respect to the direction of movement of the rotating operating section when operating the switch element compared to existing solutions. The more complex geometry of rotating operating sections compared to purely translationally movable operating elements can be accommodated by the described arrangement.

[0018] In order to make the described discharge of the excess electrical charge particularly reliable and space-saving, the invention alternatively or additionally provides that the discharge element has a discharge section that receives the excess electrical charge from the antenna section and can be directly electrically connected to the vehicle ground of the motor vehicle in order to discharge it to the vehicle ground. In other words, the discharge section is designed such that it can be directly electrically connected to the vehicle ground of the motor vehicle without the need for additional electronic components. This can be achieved, for example, by a flat conductor that connects the antenna section directly to the vehicle ground without the need for the conductor track of a PCB.

[0019] It is important that the distance between the operating section and the printed circuit board (PCB) is chosen to be large enough so that the discharge can be safely carried out via the antenna section and that there is no discharge from the operating section directly to the PCB.

[0020] In particular, a connection without additional cable harnesses is possible. This connection without any additional interposed electronic components has the advantage that the excess electrical charge can be dissipated particularly effectively to the vehicle's ground. This ensures particularly reliable protection of the sensitive electronic components described above in the vicinity of the switch element.

[0021] The invention also encompasses embodiments that provide additional advantages. One embodiment of the invention comprises the deflection element being at least one electrically conductive, plate-shaped antenna element, which is arranged perpendicular to the plane of the rotational axis of the rotatable operating section and preferably completely surrounds the rotatable operating section in this plane. This is understood, for example, to mean a metallic border that surrounds the actuating element laterally or at the edge of the actuating area.

[0022] One embodiment provides that the rotatable operating section of the switch element itself is formed from an electrically insulating material. In other words, the rotatable operating section is not suitable for absorbing an electrical charge. For example, the rotatable operating section is formed from rubber or plastic. In this case, the inventive arrangement of the needle-shaped antenna section allows the excess electrical charge to be discharged to jump over the rotatable operating section, so that the excess electrical charge is absorbed directly by the needle-shaped antenna section of the discharge element. If, for example, a user of the switch arrangement approaches the rotatable operating section with their hand, the excess electrical charge is discharged directly to the needle-shaped antenna section.This ensures effective and controlled dissipation of excess charge, which therefore cannot damage the neighboring electronic components.

[0023] An alternative embodiment provides that the rotatable operating section itself comprises an electrically conductive material and is designed to initially accumulate the excess electrical charge and, upon reaching a predetermined excess limit, to release the excess charge in a controlled manner to the at least one needle-shaped antenna section of the discharge element. In other words, the excess electrical charge can initially be discharged to the rotatable operating section. There, it is collected or trapped, so to speak, so that it cannot spread to the adjacent sensitive electronic components. The rotatable operating section can be made, for example, of a chrome-plated plastic.The inventive geometry between the rotatable operating section and the needle-shaped antenna section ensures that, upon reaching the predetermined excess charge limit, the excess charge is diverted directly to the antenna section, from where it can be discharged to the vehicle ground in a controlled manner. A further embodiment provides that the at least one switch element of the described switch arrangement is a switch element that can be integrated into a steering wheel of a steering device of the motor vehicle. In other words, the switch element can be a steering wheel switch. As such, the switch element can be designed, for example, to switch a highly automated or autonomous driving mode of the motor vehicle on and off. The switch element can also be designed as a cruise control switch for the motor vehicle.

[0024] The rotatable operating section of the switch element preferably comprises a roller designed to be rotated or rolled about the at least one rotational axis to detect an operating action. The roller can have an elongated shape, wherein the rotational axis can run along a main extension direction of the roller. The rotational axis can run centrally within the roller or eccentrically, i.e., offset from the roller's axis of symmetry. To increase the grip of the operating section, a ribbing or rubber coating can be provided along a surface of the rotatable operating section.

[0025] According to a further embodiment, the rotatable operating section alternatively or additionally comprises a sphere having at least two mutually perpendicular axes of rotation, wherein the deflection element, with its at least one antenna section, extends along its main extension direction substantially perpendicular to one of the axes of rotation. The operating section can thus be formed by or comprise a spherical operating element.

[0026] The discharge element can preferably have two or more needle-shaped antenna sections that are arranged parallel to one another at a distance from one another, with the rotatable operating section of the switch element being accommodated between the antenna sections. The antenna sections can be spaced apart from one another at a distance of 1 to 2 mm inclusive. Alternatively, a spacing in the range of 5 to 7 mm is also possible. This can preferably be selected according to the prevailing installation space situation for the switch element or the switch arrangement. In other words, the needle-shaped antenna sections form a type of basket or cage for the rotating or rotatable operating section of the switch element. This advantageously allows the switch element to be held securely in place in addition to the described ESD protection function.An advantageous development provides that the antenna sections are electrically conductively connected to one another at least in sections. In other words, the antenna sections arranged parallel to one another and spaced apart from one another can be electrically conductively connected to one another at least in sections by a further electrically conductive component. The antenna sections are preferably electrically conductively connected to one another in the region of their tips facing the operating section. The connection can in particular be designed such that the connected antenna sections form a partially or completely closed, electrically conductive ring or frame around the switch element or around the rotatable operating section of the switch element.This results in an enlarged electrically conductive surface around the rotatable operating section, so that the excess electrical charge can be dissipated particularly reliably and effectively.

[0027] A further embodiment provides for an air gap of defined width between the discharge element or its at least one antenna section and the rotatable operating section of the switch element. The provided air gap can compensate for manufacturing inaccuracies in the switch arrangement. The fact that the rotatable operating section does not lie directly against the antenna section also results in a pleasant haptic operating feeling when operating the rotatable operating section. Noise generation during operation is also advantageously reduced. The air gap preferably has a width of between 0.1 mm and 5 mm inclusive. The air gap is preferably narrower than the distance between the rotatable operating section and the other electronic component arranged closest to it.This effectively ensures that the excess electrical charge jumps across the air gap directly to the antenna section and is not passed on to the electronic component. Particularly preferably, the antenna section has a lower impedance than the electronic component arranged next to the rotatable operating section.

[0028] This allows the reliability of the discharge of the excess electrical charge to be maintained despite the presence of the air gap.

[0029] A further embodiment provides that the switch arrangement has at least one capacitive operating surface and / or at least one non-capacitive operating surface adjacent to the switch element with the rotatable operating section. For example, the switch arrangement can be a so-called 5-way scroll module. The switch arrangement can therefore be a multifunctional switch arrangement. In particular, the arrangement of a capacitive operating surface in the immediate vicinity of the rotatable operating section can be implemented without problems, since the capacitive operating surface is effectively protected from excess electrical charge by the inventive arrangement of the at least one antenna section. Thus, even if an excess electrical charge occurs between the hand of an operator of the switch arrangement and the switch arrangement itself, incorrect operation of the capacitive operating surface is advantageously prevented.

[0030] Preferably, the at least one antenna section and the discharge section of the discharge element are directly connected to one another in an electrically conductive manner. Particularly preferably, the antenna section and the discharge section are formed as a single piece.

[0031] To simplify the dissipation of excess electrical charge, a further embodiment provides for the dissipation element to contain a metal, for example, copper and / or chromium. The dissipation element can also have a plastic core and a metallized surface.

[0032] As described, the discharge element according to the invention can alternatively or additionally be designed to discharge the excess charge directly to the vehicle ground of the motor vehicle. This can be achieved by the discharge section being directly electrically conductively connected to the vehicle ground of the motor vehicle for discharging the excess electrical charge to the vehicle ground. This means that the discharge section has at least terminals that are suitable for electrically conductively connecting it, on the one hand, to the antenna section and, on the other hand, to the vehicle ground of the motor vehicle.

[0033] One embodiment in this regard provides that, in the intended installation position of the switch arrangement, the discharge element with its discharge section can be directly connected in an electrically conductive manner to a metallic component of the motor vehicle, in particular to a metallic steering wheel component of the motor vehicle, wherein the metallic component forms part of the vehicle mass of the motor vehicle. In the present context, a direct electrically conductive connection is to be understood as meaning that no further electronic component or a specially suitable electronic component, such as a voltage-dependent resistor or a diode, is interposed between the discharge section and the metallic component of the motor vehicle. This also includes additional cable sets or further connecting sections. This advantageously results in a very short and reliable discharge section for the excess electrical charge.

[0034] A further aspect of the invention relates to a steering device for a motor vehicle, comprising a steering wheel and a steering shaft or just the steering wheel alone, wherein the steering device has a switch arrangement according to the embodiments described above. In other words, the switch arrangement, which is integrated into the steering device, comprises at least one switch element and a diverter element according to the described embodiments. The at least one switch element of the switch arrangement is preferably integrated into the steering wheel of the steering device. In other words, the switch element forms part of a steering wheel switch of the steering device of the motor vehicle.

[0035] A preferred embodiment provides that an operating surface of the at least one switch element is integrated into a steering wheel strut of the steering wheel and, in particular, is flush with a surface of the steering wheel strut. The rotatable operating section can, of course, protrude beyond the surface in such a way that it can be rotated by the user's finger.

[0036] In other words, the rotatable operating portion of the switch element can protrude at least partially from the surface of the steering wheel strut. In other words, a recess can be provided in the surface or in a housing surface of the steering wheel strut, through which the rotatable operating portion of the switch element protrudes, making it accessible to an operator. The at least one antenna portion, however, can be arranged hidden beneath the surface, invisible to the user.

[0037] Preferably, the discharge section of the discharge element for discharging the excess electrical charge to the vehicle mass of the motor vehicle is directly electrically connected to a metallic steering wheel component, which, when the steering device is installed as intended, forms part of the vehicle mass of the motor vehicle. For example, when installed as intended, the metallic steering wheel component can be electrically connected to the vehicle body via the electrically conductive steering shaft of the steering device. In this case, the excess electrical charge is discharged directly to the vehicle body via the discharge section, without the need for additional intermediary electronic components.

[0038] A further aspect of the invention relates to a motor vehicle with such a steering device or steering wheel. The motor vehicle can be a truck, a passenger car, a motorcycle, or a passenger bus.

[0039] Further embodiments of the steering device according to the invention and / or the motor vehicle according to the invention follow directly from the various embodiments of the switch arrangement according to the invention, and vice versa. In particular, individual features and corresponding explanations as well as advantages relating to the various embodiments of the switch arrangement according to the invention can be transferred analogously to corresponding embodiments of the further aspects of the invention.

[0040] Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures can be encompassed by the invention not only in the respectively specified combination, but also in other combinations. In particular, the invention can also encompass embodiments and combinations of features that do not have all the features of an originally formulated claim. Furthermore, the invention can encompass embodiments and combinations of features that go beyond the combinations of features set out in the backreferences to the claims or deviate from them.

[0041] The figures show:

[0042] Fig. 1 is a schematic representation of a switch arrangement with a roller-shaped switch element;

[0043] Fig. 2 is a schematic representation of a switch arrangement with a rocker switch as the switch element; Fig. 3 is a schematic representation of parts of a switch arrangement with a spherical switch element;

[0044] Fig. 4 schematic representations of different embodiments of the discharge element according to the invention;

[0045] Fig. 5 is a schematic representation of a switch arrangement with an electrically conductive connection of two antenna sections arranged circumferentially around the rotatable operating section;

[0046] Fig. 6 is a schematic representation of a switch arrangement with an electrically conductive connection of two antenna sections arranged tangentially to the rotatable operating section;

[0047] Fig. 7 is a schematic representation of a switch arrangement with an electrically conductive connection of two antenna sections arranged tangentially to the rotatable operating section with sections projecting from the connection in a comb-like manner;

[0048] Fig. 8 is a schematic representation of a switch arrangement with an electrically conductive connection of two antenna sections arranged tangentially to the rotatable operating section, with sections projecting fan-shaped from the connection; and

[0049] Fig. 9 is a schematic representation of a section of a steering wheel surface, wherein the switch element is integrated into the steering wheel surface.

[0050] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that are to be considered independently of one another. These features also further develop the invention independently of one another and are thus to be considered as components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described. In the figures, the same reference numerals designate functionally equivalent elements.

[0051] Fig. 1 shows a schematic switch arrangement 10 with a roller-shaped switch element 12. The exemplary embodiment in Fig. 1 shows a section of the switch arrangement 10, as it can be integrated, for example, into a steering wheel device of a motor vehicle. For example, the housing section 14 shown in Fig. 1 can be part of a surface of a steering wheel of a motor vehicle or a steering wheel cover of the steering wheel. In other words, Fig. 1 shows, for example, a cross-section through a steering wheel or a steering wheel strut of a motor vehicle, wherein the switch arrangement 10 according to the invention can be integrated or installed within the housing section 14 shown.

[0052] In the embodiment shown in Fig. 1, the rotation axis r is arranged centrally within the roller-shaped switch element 12. In other words, the switch element 12 of Fig. 1 can be operated by rotating the roller in the direction 22 about the rotation axis r. This can be done, for example, by a correspondingly executed operating movement of a user of the switch assembly 10.

[0053] The arrangement shown in Fig. 1 also comprises a discharge element 16 with a needle-shaped antenna section 18 and a discharge section 20 which is, here by way of example, integrally connected thereto. The discharge section 20 can be continued and directly connected in an electrically conductive manner to a vehicle ground of the motor vehicle.

[0054] For example, if an operator of the switch assembly 10 approaches the roller-shaped switch element 12 with his finger 23, a spontaneous discharge of an excess electrical charge onto the switch element 12 may occur. If the switch element 12 comprises electrically conductive material, the switch element 12 may initially absorb the excess electrical charge.

[0055] Preferably, the switch element 12 releases the excess electrical charge to the electrically conductive antenna section 18 once a limit excess is reached.

[0056] Alternatively, the switch element 12 itself may be designed to be non-electrically conductive. To prevent the excess electrical charge from jumping to electronic components in the vicinity of the switch element 12, the needle-shaped antenna section 18 is provided. This can have a lower impedance than other electronic components in the vicinity of the switch element 12. As a result, the excess electrical charge jumps from the finger 23 directly to the antenna section 18, from where it can be diverted directly to the vehicle ground of the motor vehicle by means of the diverter section 20.

[0057] Fig. 2 shows, with reference to the components designated and described in connection with Fig. 1, a schematic representation of a switch arrangement 10, wherein here, by way of example, the switch element 12 is designed as a rocker switch. The switch element 12 can be operated by rocking back and forth along the operating direction represented here by the arrow 22. Similar to what was already described in Fig. 1, here too a needle-shaped antenna section 18 is arranged next to the switch element 12. Here too, as in the example in Fig. 1, the antenna section is spaced from an outer peripheral surface of the switch element 12 by an air gap. The air gap can have a width of 0.1 to a maximum of 5 mm.The arrangement is selected in such a way that here too an excess electrical charge preferably jumps to the antenna section 18, from where it can be passed on to the vehicle mass via the discharge section 20 indicated here.

[0058] Fig. 3 now shows a schematic representation of parts of a switch arrangement 10, wherein, for example, the switch element 12 is spherical. In the embodiment shown here, the discharge element has two needle-shaped antenna sections 18. These are connected, for example, in one piece with the discharge section 20. The discharge section 20 can be electrically connected, in particular screwed, to a vehicle body via a connecting element 24 shown schematically here in the form of a threaded ring. For this purpose, for example, a metal screw can be screwed through the threaded ring.

[0059] Regarding all switch arrangements 10 shown, it should be noted that the antenna sections 18 shown extend along their main extension direction 26 essentially perpendicular to the rotation axes r shown of the rotatable switch elements 12 shown. Fig. 4 shows schematic representations of three different embodiments of the deflection element 16 according to the invention. By way of example, the switch element 12 is again shown as a roller-shaped switch element 12. However, the configurations shown can of course also be applied to differently shaped rotatable switch elements 12, for example, to the sphere shown in Fig. 3.

[0060] From all three representations in Fig. 4, it can be seen that the antenna sections 18 shown are each arranged with their longitudinal extension direction 26 essentially perpendicular to the rotation axes r of the roller-shaped switch elements 12 shown. For the sake of clarity, only one of the antenna sections 18 is provided with a reference numeral in each of the three representations. As shown, the antenna sections 18 can each be arranged parallel to one another and spaced from one another on the discharge element 16. Antenna sections 18 can be arranged at different distances on both sides or only on one side of the roller-shaped switch element 12. In the right-hand image area of ​​Fig. 4, as many as five antenna sections 18 are shown, one of the antenna sections 18 being arranged on an end face of the roller-shaped switch element 12.

[0061] Fig. 5 shows a schematic representation of a switch element 12, which is completely surrounded tangentially by an electrically conductive connecting structure 28, which electrically connects the two antenna sections 18 shown. This results in a particularly efficient dissipation of the excess electrical charge. The connecting structure 28 connects the antenna sections 18 in the region of their tips facing the switch element 12.

[0062] In Fig. 6, such a connecting structure 28 is arranged tangentially to the rotating switch element 12.

[0063] In the embodiment shown in Fig. 7, additional sections 30 are shown, which extend comb-like from the connecting structure 28 of the antenna sections 18 toward the roller-shaped switch element. The sections 30 are preferably also electrically conductive and can absorb the excess charge.

[0064] Fig. 8 shows an embodiment in which the electrically conductive sections 30 are arranged in a fan-shaped manner on each of the antenna sections 18 and are oriented toward the roller-shaped switch element. The sections 30 can also be formed as fibers or hairs of a wire brush that is electrically conductively connected to the antenna sections 18, which can additionally protect the air gap from contamination.

[0065] To manufacture the switch assembly 10, for example, a housing can first be provided into which the discharge element 16 can be inserted. The discharge element 16 can also be overmolded with the housing. The electrically conductive sections 30 can, for example, be melted onto the antenna sections 18 or clipped onto them.

[0066] Finally, Fig. 9 shows a schematic representation of a section of a housing surface or a housing section 14, which can, for example, belong to a steering wheel surface of a steering wheel for a motor vehicle. The switch element 12, in the embodiment shown here, is designed as a so-called 5-way scroll module. The rotatable operating section 32 is located in the central region of the switch element 12. This can be rotated and thus operated according to the operating directions 22 shown above. Arranged laterally with respect to the rotatable operating section 32 are two buttons or operating surfaces 34, which can, for example, be capacitive operating surfaces 34.Due to the effective dissipation of the excess electrical charge by the described arrangement with antenna section 18 and discharge section 20, the capacitive control surfaces 34 are effectively protected from damage caused by a brief current flow during the discharge of the excess electrical charge. The discharge element 16 is located on the rear side of the 5-way scroll module (not visible in Fig. 9).

[0067] To test the effectiveness of the inventive concept, the switch arrangement was replicated in a test bench. Three air gap widths of 0.5 mm, 1 mm, and 5 mm were set. The distance between the switch element and the nearest sensor was always 7 mm in the setup. The electrical discharge voltages set included +15 kV and -15 kV. For the air gap width of 0.5 mm, the test was carried out ten times for each voltage, with the discharge occurring via the antenna section each time. For the air gap width of 1 mm, eight tests were carried out at +15 kV and ten tests at -15 kV, with the discharge also occurring via the antenna section each time. For the air gap width of 1 mm, the test was carried out 30 times for each voltage, with the discharge also occurring via the antenna section each time.

[0068] While a steering wheel assists the driver in steering a vehicle, the electronics integrated into the steering wheel support the driver by enabling quick access and easy control of many functions. Furthermore, convenience functions are enabled with this so-called steering wheel switch electronics, which are controlled, for example, via steering wheel switches (SWS).

[0069] To ensure that the electronics and their intended functions function reliably and flawlessly in a vehicle, the electronics must be robust against electrostatic discharge (ESD). Technically speaking, electrostatic discharge is a temporary event in which the electrical potentials of two objects equalize whenever there is an opportunity for charge exchange (through electrical current). This occurs either via a transfer medium such as air or through direct physical contact. This is known to damage or even destroy sensitive electronics.

[0070] To validate the robustness of electronics at both the vehicle and component levels, compliance with standardized test procedures (as described in ISO 10605) is required. Within the tests, "touchable points" and "enclosure openings" are tested at the component level. This includes both contact discharges, e.g., in the case of physical contact between two objects with different potential, as well as discharges via air. In both cases, the unintentional flow of compensating charges to the component, including its printed circuit board (PCB) and the electronic components mounted on it, is validated. The discharge path with the lowest impedance is usually favored by the compensating ESD current. For components within a vehicle, this is realized either remotely, as with terminal 31, or locally, as via the vehicle chassis.

[0071] In addition to direct discharge onto a roller and tilt wheel, integrating a roller and tilt wheel into a steering wheel requires the steering wheel cover to be cut to fit the dimensions of the roller and tilt wheel. After installation, an open gap typically remains between the roller and tilt wheel and the steering wheel cover. In known arrangements, the gap around the roller and tilt wheels allows ESD air discharge directly onto the electronic components mounted on the circuit board, potentially damaging them. When capacitive touch panels are used as part of steering wheel switches (SWS), they are, by design, sensitive to the electrical charges in their surroundings. The presence of additional charges near this panel can lead to false detection of touch events. To ensure proper operation, the charge must therefore be effectively dissipated, which is made possible by the present invention.

[0072] The invention thus ensures the ESD-safe design of the touch and scroll wheel with capacitive touch functionality for steering wheel switches. This is also relevant because the integration of a touch and scroll wheel into a steering wheel switch involves moving parts and, due to the nature of the application, requires housing openings.

[0073] The invention covers ESD events on the components (e.g., the touch and scroll wheel and / or the capacitive touch panel) as well as in their immediate vicinity. It is applicable to conductive and non-conductive switch elements and parts thereof, as well as to conductive and non-conductive environments. In addition, unintentional propagation via low-resistance paths (such as signal lines or power supply lines) can be prevented by directing the ESD current to the steering wheel skeleton.

[0074] An embodiment of the invention also allows for the active dissipation of charges from the conductive tip and the scroll wheels during use.

[0075] The inventive mechanical structure of the discharge element is intended to redirect, deflect, and guide the ESD discharge current along the intended path with the lowest impedance. It protects nearby electronic components and vehicle wiring networks from ESD damage.

[0076] The antenna section is an additional electrical contact that ensures the successful dissipation of ESD discharges. It can also be an electrically conductive spring located closer to the switch element (scroll wheel) than the nearest electronic components or the printed circuit board (PCB).

[0077] Various mechanical implementations are conceivable:

[0078] - single or multiple needle-shaped antenna sections in the manner of a comb like a comb (see Fig. 4);

[0079] - a solid sheet metal version covering the dimensions of the switch element (see Fig. 5);

[0080] - a sheet metal version with different shapes (see e.g. Fig. 6 to 8);

[0081] - a version with a ring that completely or partially encloses the tip and the scroll wheel.

[0082] The antenna section and / or the connecting structure can be positioned in the intended installation position both perpendicularly and tangentially, or in other orientations, to the steering wheel. Parallel designs of a ring arranged circumferentially around the switch element are also possible to establish the discharge contact. For this purpose, plates or spikes can be provided on one or more sides of the rotating operating section (e.g., the rocker or roller switch, tip wheel, or scroll wheel).

[0083] The discharge section can divert the electrical discharge current from the antenna section to the vehicle ground in a defined manner. An example of a discharge path runs via a screw connection point on the steering wheel skeleton, which is directly connected to the steering wheel skeleton in an electrically conductive manner.

[0084] The antenna section is designed to cover the following two cases:

[0085] 1 . The discharge first occurs at the conductive switch elements and, when the excess charge limit is reached, the discharge current flows from the switch elements to the antenna section instead of to the electronic parts and the circuit board.

[0086] 2. the discharge occurs directly onto the antenna section, e.g. if the switch element itself is not electrically conductive.

[0087] In both cases, the ESD discharge is redirected to the steering wheel skeleton and protects the electronics and the circuit board from damage.

[0088] The discharge section is designed to be low-impedance, low-inductance, conductive, and remote and / or insulated from the circuit board and other electronic components, preventing any discharge from the discharge section to the circuit board and other electronic components. An alternative is a lower-resistance connection of the discharge section to the steering wheel or steering wheel frame rather than to a nearby electronic component.

Claims

Patent claims 1. A switch arrangement (10) for a motor vehicle, comprising at least one switch element (12) and an electrically conductive discharge element (16, 28), wherein the discharge element (16, 28) is arranged in the vicinity of the switch element (12) and is designed to discharge an excess electrical charge from the vicinity of the switch element (12) to a vehicle mass of the motor vehicle in a controlled manner, characterized in that the switch element (12) has a rotatable operating section (32) with at least one axis of rotation (r), wherein the discharge element (16, 28) is arranged relative to the operating section (32) such that an excess electrical charge can be discharged from the rotatable operating section (32) or its vicinity to the vehicle mass, and / or that the discharge element (16) has a discharge section (20) which can be directly electrically conductively connected to the vehicle mass of the motor vehicle in order to discharge the excess electrical charge to the vehicle mass of the motor vehicle.

2. Switch arrangement (10) according to claim 1, characterized in that the diverting element (16) has at least one needle-shaped antenna section (18) which extends along its main extension direction (26) substantially perpendicularly with respect to the at least one rotation axis (r) of the rotatable operating section (32) 3. Switch arrangement (10) according to claim 1 or 2, characterized in that the diverting element (16, 28) is at least one electrically conductive plate-shaped antenna element (28) which is arranged perpendicular to the plane of the rotation axis (r) of the rotatable operating section (32) and preferably completely circulates the rotatable operating section (32) in this plane.

4. Switch arrangement (10) according to one of the preceding claims, characterized in that the at least one switch element (12) is a switch element (12) that can be integrated into a steering wheel of a steering device of the motor vehicle.

5. Switch arrangement (10) according to one of the preceding claims, characterized in that the rotatable operating section (32) of the switch element (12) comprises a roller which is designed to be rotated about the at least one rotation axis (r) in order to detect an operating action.

6. Switch arrangement (10) according to one of the preceding claims, characterized in that the rotatable operating section (32) of the switch element (12) comprises a sphere which has at least two mutually perpendicular axes of rotation (r), wherein the diverting element (16) extends with its at least one antenna section (18) along its main extension direction (26) substantially perpendicularly with respect to one of the axes of rotation (r).

7. Switch arrangement (10) according to one of the preceding claims, characterized in that the diverting element (16) has two or more needle-shaped antenna sections (18) which are arranged parallel to one another at a distance from one another, wherein the rotatable operating section (32) of the switch element (12) is received between the antenna sections (18).

8. Switch arrangement (10) according to claim 7, characterized in that the antenna sections (18) are at least partially electrically conductively connected to one another, in particular in such a way that a partially or completely closed, electrically conductive ring is formed around the switch element (12) by the connected antenna sections (18).

9. Switch arrangement (10) according to one of the preceding claims, characterized in that between the diverting element (16) or its at least one antenna section (18) and the rotatable operating section (32) of the switch element (12) there is an air gap of defined width, wherein the air gap is between 0.1 millimeters and 5 millimeters inclusive.

10. Switch arrangement (10) according to one of the preceding claims, characterized in that the switch arrangement (10) has at least one capacitive operating surface (34) and / or at least one non-capacitive operating surface (34) adjacent to the switch element (12) with the rotatable operating section (32).

11. Switch arrangement (10) according to one of the preceding claims, characterized in that the at least one antenna section (18) and the discharge section (20) are electrically conductively connected to one another.

12. Switch arrangement (10) according to claim 11, characterized in that the at least one antenna section (18) and the discharge section (20) are formed in one piece.

13. Switch arrangement according to one of the preceding claims, characterized in that the discharge element (16) with its discharge section (20) can be connected directly in an electrically conductive manner to a metallic component of the motor vehicle, in particular to a metallic steering wheel component of the motor vehicle, wherein the metallic component forms part of the vehicle mass of the motor vehicle.

14. Steering wheel for a motor vehicle, wherein the steering device has a switch arrangement (10) with at least one switch element (12) and a diverting element (16) according to one of the preceding claims, wherein the at least one switch element (12) of the switch arrangement (10) is integrated into the steering wheel.

15. Motor vehicle with a steering wheel according to claim 14.

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