Switching control element

Abstract

Switching control element for a motor vehicle with an actuating surface (8) for manual action by means of an element (9) and with a capacitive sensor encompassing the actuating surface (8), wherein the actuating surface (8) can be supplied with an electrical voltage such that the sensor generates a signal when the element (9) approaches the actuating surface (8) and / or when the actuating surface (8) is touched by the element (9) and / or when pressure is applied to the actuating surface (8) by the element (9), and wherein the actuating surface (8) is in electrical contact with a contact surface on a circuit board (10) by means of an electrical conductor (11) for supplying the electrical voltage, characterized in that an electrically conductive elastomer is provided as the electrical conductor (11), wherein a support element (13) arranged on the circuit board (10) is provided for the actuating surface (8), wherein the support element (13) is made of plastic and wherein the electrically conductive elastomer (11) is injected into the carrier element (13) during its manufacture by injection molding in the manner of a two-component (2K) part.

Description

[0001] The invention relates to a switching control element according to the preamble of claim 1.

[0002] Such control elements are used in motor vehicles to allow a user to operate a wide variety of functions. For example, the control element can be located in the steering wheel, dashboard, center console, armrest, or similar locations within the vehicle.

[0003] Such a switching control element has an actuation surface for manual operation by the user. In particular, this element can be a finger of a human hand, with which the switching control element is actuated. The actuation surface includes a capacitive sensor, and the actuation surface can be subjected to an electrical voltage such that the sensor generates a signal when the element approaches the actuation surface, and / or when the element touches the actuation surface, and / or when pressure is applied to the actuation surface by the element. This signal serves, in particular, to switch and / or trigger a function in the motor vehicle in the form of a switching signal.

[0004] To supply electrical voltage, the actuating surface is electrically connected to a contact pad on a circuit board via an electrical conductor. It has been observed that in some cases, contact problems with the electrical conductor occur, resulting in an air gap between the actuating surface and the actuator. This air gap, in turn, negatively affects the electric field generated at the actuating surface, leading to inaccuracies in the operation of the switch, where the user's intended action is not correctly or even correctly recognized.

[0005] Switching controls and aspects of such switching controls are known in the prior art, for example, from documents US 2013 / 0270926 A1, US 2012 / 0161795 A1, DE 10 2006 045 712 A1, US 2012 / 0306802 A1 and US 2008 / 0111714 A1.

[0006] The invention is based on the objective of further developing the switching control element in such a way that the accuracy of the operation is improved.

[0007] This problem is solved in a generic switching control element by the characterizing features of claim 1.

[0008] In the switching element according to the invention, an electrically conductive elastomer is provided as the electrical conductor. Advantageously, such an elastomer possesses a certain mechanical preload, so that its shape remains largely stable even under compression, thus ensuring reliable electrical contact. The formation of air gaps is consequently prevented, thereby ensuring precise operation of the switching element by the user. Further embodiments of the invention are the subject of the dependent claims.

[0009] To further enhance the functional and / or operational reliability of the switching element, the electrical conductor can be clamped between the actuating surface and the circuit board. A cost-effective solution is to use an electrically conductive rubber elastomer. Furthermore, a housing can be provided for the switching element. The actuating surface can advantageously be designed as a cover on the housing. To protect it from external influences, the circuit board can be located inside the housing. Electronics forming part of the capacitive sensor can be compactly arranged on the circuit board.

[0010] According to the invention, a support element arranged on the circuit board is provided for the arrangement and / or mounting of the actuating surface. The support element is made of plastic in a cost-effective manner. The electrically conductive elastomer is injected into the support element during its production by injection molding, similar to a two-component (2K) part, which is simple to manufacture and also contributes to the compactness of the switching element.

[0011] For an illuminated control element, a light source, in particular a light-emitting diode (LED), can be provided. Advantageously, the light source is located on the circuit board. As a functional extension for the carrier element, this can be designed as a reflector to direct the light emitted by the light source. This allows the operating surface of the control element to be illuminated in a simple manner.

[0012] The following can be stated for a particularly preferred embodiment of the switching control element according to the invention.

[0013] Capacitive switching elements require an electrically conductive element for the electrical connection between the circuit board and the actuating surface. Electrical contact in this arrangement must always be ensured, as an air gap negatively affects the capacitive field. A flexible element with a preload and a flexible shape is used as the conductive element – ​​specifically, a conductive rubber actuating surface. These can be injection-molded like plastic parts. Furthermore, they are rigid enough to retain their shape while still being compressible to a certain degree. The result is a flexible, electrically conductive actuating element that is particularly suitable for capacitive automotive applications.

[0014] The advantages achieved with the invention lie particularly in the fact that the switching element is compact and reliably operable. Furthermore, the switching element can be manufactured cost-effectively and is therefore also suitable for mass production. In addition, the switching element according to the invention is also suitable for the simple implementation of customer-specific designs. An embodiment of the invention with various further developments and configurations is shown in the drawings and is described in more detail below. The drawings show... Fig. 1 schematically a steering wheel with a control unit comprising a shift control element for a motor vehicle and Fig. 2 the switching element off Fig. 1 as a cut-up individual piece.

[0015] In Fig. Figure 1 shows a steering wheel 1 for a motor vehicle. The steering wheel 1 comprises a steering wheel rim 2, steering wheel spokes 3, and a central steering wheel hub 4, in which, for example, an airbag may be located. A control unit 5, 5' in the form of a multifunction switch for various devices in the motor vehicle, such as the car radio, the telephone, a navigation system screen, or the like, is arranged on two of the lateral steering wheel spokes 3.

[0016] In one control unit 5, a signal transmitter 7 in the form of a rotary encoder is arranged. For example, by manually rotating the rotary encoder 7, the operator can scroll through a menu on a screen in the vehicle. In the other control unit 5', switching elements 6 are arranged for triggering and / or switching functions of the vehicle or the devices to be controlled in the vehicle.

[0017] As closer to Fig. As shown in Figure 2, the switching control element 6 has an actuation surface 8 for manual operation by means of an element 9. The element 9 is, in particular, a finger of a human hand. Of course, a pen or similar object can also be used as element 9. The actuation surface 8 comprises a capacitive sensor, which can be subjected to an electrical voltage. Due to the change in capacitance caused by a change in the electric field at the actuation surface 8 when the element 9 approaches the actuation surface 8 and / or when the element 9 touches the actuation surface 8 and / or when pressure is applied to the actuation surface 8 by means of the element 9, the capacitive sensor generates a signal. This signal is then used, for example, to switch and / or trigger a function of the vehicle in the form of a switching signal.

[0018] To apply the electrical voltage to the actuating surface 8, the actuating surface 8 is in electrical contact with a contact surface on a printed circuit board 10 for supplying the electrical voltage by means of an electrical conductor 11. The electrical conductor 11 is an electrically conductive elastomer. The elastomer 11 is preferably an electrically conductive rubber. For good contact, the electrical conductor 11 is clamped between the actuating surface 8 and the printed circuit board 10.

[0019] The switching control element 6 has a housing 12. The actuation surface 8 is designed as a cover on the housing 12. The circuit board 10 is located inside the housing 12. Electronics forming part of the capacitive sensor are arranged on the circuit board 10. Furthermore, a support element 13 for the actuation surface 8 is provided on the circuit board 10. The support element 13 is made of plastic. The electrically conductive elastomer 11 is injected into the support element 13 during its manufacture by injection molding, similar to a two-component (2K) part. The support element 13 is designed as a reflector to guide light. This allows light emitted from a light source, for example, a light-emitting diode, on the circuit board 10 to be directed to the actuation surface 8 in such a way that the actuation surface 8 can be illuminated.

[0020] The invention is not limited to the described and illustrated embodiment. Rather, it also encompasses all technically advanced developments within the scope of the invention defined by the claims. Thus, a switching control element 6 according to the invention can be used not only for multifunction switches in the steering wheel but also for other control switches, control panels in the automotive and / or consumer sectors, or the like. Reference symbol list 1 steering wheel 2 Steering wheel rim 3 steering wheel spokes 4 Steering wheel hub 5.5' Control unit (on the steering wheel) 6 Switching control element 7 Signal transmitters 8 operating area 9 Element 10 circuit boards 11 (electrical) conductor / elastomer 12 cases 13 Support element

Claims

Switching control element for a motor vehicle with an actuating surface (8) for manual operation by means of an element (9) and with a capacitive sensor encompassing the actuating surface (8), wherein the actuating surface (8) can be supplied with an electrical voltage such that the sensor generates a signal when the element (9) approaches the actuating surface (8) and / or when the actuating surface (8) is touched by means of the element (9) and / or when pressure is applied to the actuating surface (8) by means of the element (9), and wherein the actuating surface (8) is in electrical contact with a contact surface on a printed circuit board (10) for supplying the electrical voltage by means of an electrical conductor (11), characterized in that an electrically conductive elastomer is provided as the electrical conductor (11), wherein a support element (13) for the actuating surface (8) is provided on the printed circuit board (10).wherein the carrier element (13) is made of plastic and wherein the electrically conductive elastomer (11) is injected into the carrier element (13) during its manufacture by injection molding in the manner of a two-component (2K) part. Switching control element according to claim 1, wherein the signal serves to switch and / or trigger a function in the manner of a switching signal. Switching control element according to claim 1 or 2, characterized in that the electrical conductor (11) is clamped between the actuating surface (8) and the circuit board (10). Switching control element according to claim 1, 2 or 3, characterized in that the elastomer (11) is an electrically conductive rubber. Switching control element according to one of the preceding claims, characterized in that a housing (12) is provided. Switching control element according to the preceding claim, wherein the actuating surface (8) is designed in the form of a cover on the housing (12). Switching control element according to the preceding claim, wherein the circuit board (10) is located inside the housing (12). Switching control element according to the preceding claim, wherein electronics forming a component of the capacitive sensor are arranged on the circuit board (10). Switching control element according to one of the preceding claims, characterized in that the carrier element (13) is designed in the manner of a reflector for guiding light emitted by a light source on the circuit board (10) such that the actuating surface (8) can be illuminated. Switching control element according to the preceding claim, wherein the light source is a light-emitting diode.

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