OPERATING ELEMENT WITH A LAYERED ACTION PART

Description

[0001] The invention relates to a control element with an actuating part that has an actuating surface for user input. Force sensors are assigned to the actuating part to detect actuation beyond mere contact. Actuation is defined as a displacement of the actuating part under the influence of an actuating force applied by the user and acting on the actuating surface. For this purpose, the actuating part is typically mounted elastically on a support. This elastic displacement also serves to generate passive haptic feedback, which results from the force-displacement curve during actuation.Furthermore, the elastic mounting also serves to dampen, restore, and / or decouple vibrations from the substrate when the actuator is moved by an electrical control signal, thus generating active haptic feedback for the user. In cases where the actuator is mounted on a movable surface, whether for restoring movement (passive feedback) or for active haptic feedback, a problem arises: a clearance must be maintained in a transition area between the actuator and the substrate, particularly between the actuator and an aperture fixed to the substrate, to ensure its mobility. This clearance poses a risk of ingress of foreign matter, such as fluids or dust particles, which could compromise the functionality of the control element.Furthermore, setting a uniform gap between the cover and the actuator for aesthetic reasons presents enormous challenges for the assembly of the control element.

[0002] Against this background, there was a need for a solution for a control element with an elastically yielding actuating part, which is improved with regard to its structural connection to the carrier, in order to, among other things, make it more difficult for foreign bodies to penetrate and, in particular, to achieve a more visually appealing appearance in the transition area between the carrier or cover and the actuating part. This objective is achieved by a control element according to claim 1. An equally advantageous use is the subject of the dependent claim. Advantageous embodiments are the subject of the dependent claims. It should be noted that the features listed individually in the claims can be combined with one another in any technologically meaningful way and demonstrate further embodiments of the invention. The description, especially in conjunction with the figures, further characterizes and specifies the invention.

[0003] WO 2008 / 006710 A1 discloses a control element according to the preamble of claim 1.

[0004] The invention relates to a control element. The term "control element" is to be interpreted broadly and refers to the input of a user by means of a movable actuating part within the framework of a human-machine interface. The control element according to the invention has a carrier. The term "carrier" is to be interpreted broadly and means a component that is part of a load-bearing structure or is, for example, directly or indirectly attached to a motor vehicle component. For example, the carrier is designed as a slip-on housing. The carrier is, for example, made of a plastic, a metal, or a metallic alloy such as ZAMAK, or combinations thereof.

[0005] According to the invention, an actuating element is further provided, which has an actuating surface facing the operator for the operator to make an operating input. An actuating input is understood to be an actuation by an operator that goes beyond mere contact, in particular involving simultaneous contact, in which the operator applies an actuating force acting perpendicularly to the actuating surface in order to cause a displacement of the actuating element following the actuating force, here with elastic, partial deformation of the actuating element. According to the invention, the actuating element further has an edge region arranged outside the actuating surface, preferably surrounding the actuating surface, and more preferably an outer edge region, by means of which the actuating element is supported on the support.

[0006] According to the invention, the actuating part has a layer structure defining the actuating surface, preferably a film layer structure.

[0007] According to the invention, the layer structure comprises at least two layers, each made of a thermoplastic. According to the invention, at least two of the layers, i.e., more precisely, the materials used to form the layers, differ in their modulus of elasticity. According to the invention, a transition region is provided between the edge region and the actuating surface. The transition region is characterized in that, within the transition region, the layer with the lowest modulus of elasticity of the two layers, which is referred to as the highly elastic layer, has the greatest layer thickness, measured in a direction perpendicular to the actuating surface, compared to the layer thickness of the other layers of the layer structure in the same transition region, in order to provide elastic compliance of the actuating element in a direction perpendicular to the actuating surface.Preferably, a high-strength layer exhibiting the highest modulus of elasticity of the multiple layers of the layer structure is removed, i.e., not present, in the transition region, so that at least the highly elastic layer remains in the transition region, for example, only a film of the film layer structure and the highly elastic layer.

[0008] According to the invention, a force sensor is arranged and / or acting between the carrier and the actuating element to detect a displacement of the actuating element in the direction perpendicular to the actuating surface. The term "force sensor" is to be interpreted broadly: In a simple embodiment, it is an electromechanical switch that changes its switching state depending on the position of the actuating element.

[0009] According to the invention, the force sensor is a non-contact detecting force sensor, such as a capacitive, optical, and / or inductive force sensor that detects the actuating force. In another embodiment, the force sensor is designed to detect the actuating force based on a mechanical action acting on a component of the force sensor, such as a resistive or piezoelectric force sensor. Preferably, the force sensor is configured to determine the relative displacement between the actuating part and the support, for example capacitively, by measuring a change in measuring capacitance between an electrode fixed to the actuating part and an electrode fixed to the support.

[0010] The highly elastic layer, due to its placement, provides pronounced local elastic compliance in the area surrounding the actuating surface of the actuator. Furthermore, no additional elastic support is required. The highly elastic layer ensures a fluid-tight connection between the actuating surface and the carrier. This allows the actuator, including its elastic support, to be manufactured in a single step, for example, by thermal forming in a mold. This simplifies the manufacturing and assembly of the control element. The highly elastic layer allows the actuating surface of the actuator to move freely without the need for a gap between the carrier and the actuator. The highly elastic layer also provides reliable restoring action and prevents the actuator material from being subjected to excessive stress beyond its elastic capacity.This reliably prevents plastic, non-reversible deformations of the actuating element. Preferably, in addition to the actuating surface, the transition area is also a visible surface, meaning it is freely accessible to the operator. Preferably, the actuating surface, transition area, and edge area form a continuous, seamlessly transitioning visible surface facing the operator.

[0011] Preferably, the layer structure, or film layer structure, is formed in one piece, for example by bonding the layers or film together.

[0012] According to the invention, in the transition area located between the edge region and the actuating surface, a material weakening in the layer structure is formed which surrounds the actuating surface at least section by section, and optionally completely surrounds the actuating surface, in order to provide elastic compliance of the actuating part in a direction perpendicular to the actuating surface.

[0013] In one embodiment, the extent of the material weakening in the circumferential direction relative to the actuating surface is adapted to the extent of the edge region with which the actuating element is supported on the carrier. For example, the actuating element has a freestanding edge section that is not supported on the carrier.

[0014] For example, the material weakening is designed to extend through all layers except the highly elastic layer and the optional film of the layer structure. In one embodiment, the material weakening projects into the highly elastic layer without penetrating it at the transition zone. Due to its placement, the material weakening provides a pronounced local elastic compliance in the area of ​​the actuating part surrounding the actuating surface.

[0015] Preferably, the material weakening is formed by a circumferential groove provided on the side of the actuating part facing away from the operator, so that the surface of the actuating part facing the operator, which includes the actuating surface and the surface of the edge area facing the operator, is not interrupted by the groove.

[0016] For the mechanical stabilization of the actuating part, especially in the area of ​​the actuating surface, the high-strength layer, which has the highest modulus of elasticity of the several layers, extends essentially parallel to the actuating surface.

[0017] Preferably, the high-strength layer exhibiting the lowest modulus of elasticity among the multiple layers is made of a thermoplastic such as polyethylene (PE), polycarbonate (PC), polystyrene (PS), polyvinyl chloride (PVC), polyamides (PA), acrylonitrile butadiene styrene (ABS), or polymethyl methacrylate (PMMA). Preferably, the high-strength layer is made of PC or ABS.

[0018] According to the invention, an actuator for exciting vibration and / or movement of the actuating part, and thus for generating active haptic feedback, is further provided. This actuator is arranged between the carrier and the actuating part. The actuator is an active actuator, i.e., an actuator that can be triggered by a control signal provided by control electronics. By injecting an impulse, such as a shock or vibration, into the adjacent component, namely the actuating part, it is able to excite movement or vibration within the latter, which is haptically perceptible to the operator via their finger resting on the actuating surface. This haptic perception serves, for example, as a confirmation signal for a touch or actuation, or as haptic acknowledgment of a switching or control function assignment made by an evaluation unit.Preferably, the actuator is an inertial, motor-based actuator, such as a motor on whose rotating drive shaft a mass is mounted eccentrically with respect to its center of gravity, or a magnetic coil actuator, a piezoelectric actuator, or a linear broadband actuator, such as a voice coil actuator or a linear resonant actuator. According to the invention, the actuator is exclusively fixed to the actuating part by force or material bonding, for example, by screwing or bonding. An electromagnetic actuator acting attractively or repulsively between the support and the actuating part can also be provided.

[0019] Preferably, the highly elastic layer is formed from a thermoplastic elastomer, such as a thermoplastic polyurethane, or a thermoplastic vulcanizate, such as a vulcanizate comprising an ethylene propylene diene rubber.

[0020] Preferably, the highly elastic layer has a Shore A hardness in the range of more than 55 to less than 95, more preferably in the range of 65 to 85.

[0021] As mentioned previously, the layer structure is preferably a film layer structure containing a film, such as a polycarbonate film (PC film). More preferably, the film is an outer layer of the film layer structure that forms the actuating surface.

[0022] Preferably, the film forms a common viewing surface extending over the operating area, the transition area and the edge area.

[0023] For example, the input part is produced as follows: In a first forming step, a thermoplastic, such as PC or ABS, is molded into a preform that forms the high-strength layer of the film structure to be produced. In a subsequent step, a film, such as a PC film, and the preform are placed into the cavity of a mold, leaving a cavity between them. In a subsequent injection molding step, the cavity is filled with the remaining thermoplastic, such as the thermoplastic elastomer or the thermoplastic vulcanizate, in a thermal injection molding process to form a single-piece film structure whose layers or film are bonded together.

[0024] Preferably, the actuating part has an opening in which a manually operable electronic or electromechanical input part, such as a rotary actuator or a roller actuator preferably operated with the thumb of the hand resting on the steering wheel rim, is arranged.

[0025] Furthermore, a capacitive touch sensor can be provided to detect contact with the actuator in the area of ​​the actuating surface. For example, at least one conductive layer is applied to the side of the actuator facing away from the operator to provide an electrode structure for the electrical touch sensor to detect contact with the actuating surface. For example, the conductive layer or layers form an array of electrodes that serve for the capacitive, spatially resolved detection of contact on the actuating surface. The methods for contact detection are known to those skilled in the art; for example, the electrodes are supplied with different potentials to generate a measuring field penetrating the actuating surface, defining a measuring capacitance, which is influenced by contact from the operator.The resulting influence on the measuring capacity is detected by an evaluation unit. According to a preferred embodiment, with a uniform spatial distribution of the array across the actuation surface, spatially resolved detection of contact on the actuation surface is possible.

[0026] According to a preferred embodiment of the control element, the actuating surface comprises at least one backlit illuminating surface, which, for example, reproduces the shape and / or outline of a symbol. At least one layer of the layer structure forms a recess or opening to create a light channel, directing light from a light source fixed to the substrate to the illuminating surface for backlighting.

[0027] The invention further relates to an arrangement comprising a control element in one of the previously described embodiments and a motor vehicle steering wheel, wherein the control element is arranged in the region of a spoke of the motor vehicle steering wheel extending between a steering wheel rim and a steering wheel hub. Preferably, the actuating element is formed integrally with a cover over its edge region, the cover extending around a deflector cup covering the steering wheel hub. For example, the carrier and the cover are rigidly connected to one another.

[0028] The invention further relates to the use of the control element in one of the previously described embodiments in a motor vehicle.

[0029] The invention is explained in more detail with reference to the following figures. The figures are to be understood as examples only and each represents merely one preferred embodiment. They show: Fig. 1 a sectional view of an embodiment of the control element 1 according to the invention, Fig. 2 a top view of the arrangement according to the invention; Fig. 3 a rear view of the cover made of Figure 2 .

[0030] Figure 1 Figure 1 shows a first embodiment of the control element 1 according to the invention. It serves to make an operating input by means of a movable actuating part 2 within the framework of a human-machine interface.

[0031] The control element 1 according to the invention has a carrier 20. The term "carrier" refers to a component that is part of a load-bearing structure or is, for example, directly or indirectly attached to a motor vehicle component, such as a steering wheel. Here, the carrier 20 is designed as a slip-on housing. The carrier 20 is, for example, made of a plastic, a metal, or a metallic alloy such as ZAMAK, or combinations thereof.

[0032] Furthermore, an actuating element 2 is provided, which has an actuating surface 3 facing an operator B for the operator B to make an operating input. An actuating input is understood to be an actuation by the operator B that goes beyond mere contact, in particular involving simultaneous contact, in which the operator B applies an actuating force acting perpendicularly on the actuating surface 3 in order to cause a displacement of the actuating element 2 following the actuating force, here with elastic, partial deformation of the actuating element 2. The actuating element 2 also has an outer edge region 5 arranged outside the actuating surface 3 and surrounding the actuating surface 3, by means of which the actuating element 2 is supported on the carrier 20.

[0033] Furthermore, the actuating element 2 has a layer structure 2a, 2b, 2c defining the actuating surface 3, which is designed as a film layer structure. The layer structure 2a, 2b, 2c comprises a film 2a and two layers 2b, 2c, each made of a thermoplastic. At least two of the layers 2b, 2c, i.e., more precisely, the materials used to form the layers, differ in their modulus of elasticity. A transition zone 4 is provided between the edge region 5 and the actuating surface 3.The transition zone 4 is characterized by the fact that the layer with the lowest modulus of elasticity of the two layers, designated as the highly elastic layer 2b, has the greatest thickness in a direction R perpendicular to the actuating surface 3 compared to the thickness of the other layers 2a, 2c of the layer structure 2a, 2b, 2c in the transition zone 4, in order to provide elastic compliance of the actuating part 2 in the direction R perpendicular to the actuating surface 3. More precisely: Only one highly elastic layer 2b is provided in the transition zone 4.

[0034] Furthermore, a force sensor 7 is provided between the carrier 20 and the actuating part 2 to detect the displacement of the actuating part 2 in the direction R perpendicular to the actuating surface 3. This is a capacitive force sensor 7.

[0035] Due to its placement in the transition area 4, the highly elastic layer 2b provides pronounced local elastic compliance in this area of ​​the actuator 3 surrounding the actuating surface 3. Furthermore, no other elastic support is required. The highly elastic layer 2b also ensures a liquid-tight transition between the actuating surface 3 and the carrier 20. This allows the actuator 2, including its elastic support, to be manufactured in a single production step, for example, by thermal forming in a mold. This simplifies the manufacturing and assembly of the control element 2. The highly elastic layer 2b enables the actuator 3 of the actuator 2 to move freely without the need for a gap between the carrier 20 and the actuator 2.Furthermore, the highly elastic layer 2b provides reliable restoring and prevents overstressing of the material of the actuating part 2 beyond its elastic capacity. Thus, plastic, non-reversible deformations of the actuating part 2 are reliably prevented. Here, not only is the actuating surface 3, but also the transition area 4, which is a visible surface and therefore freely accessible to the operator B. Rather, the actuating surface 3, transition area 4, and edge area 5 form a continuous and seamlessly transitioning visible surface facing the operator B.

[0036] As in Figure 1As can be seen, in the transition area 4 located between the edge area 5 and the actuating surface 3, a material weakening 10 is formed in the form of a groove in the layer structure 2a, 2b, 2c on the side of the actuating part 2 facing away from the operator B, in order to provide an elastic compliance of the actuating part 2 in the direction R perpendicular to the actuating surface 3.

[0037] The material weakening 10 is designed in such a way that it extends through all layers except for the highly elastic layer 2b and except for the foil 2a of the layer structure 2a, 2b, 2c.

[0038] For the mechanical stabilization of the actuating part 2, particularly in the area of ​​the actuating surface 3, the high-strength layer 2c, which has the highest modulus of elasticity of the several layers, extends essentially parallel to the actuating surface 3.

[0039] Furthermore, an actuator 6 is provided for exciting vibration and / or movement of the actuating part 2 and thus for generating active haptic feedback. This actuator is arranged between the carrier 20 and the actuating part 2. The actuator is an active actuator, meaning it can be triggered by a control signal provided by a control electronics unit 21. By injecting an impulse, such as a shock or vibration, into the adjacent component, namely the actuating part 2, the actuator is able to excite movement or vibration within it. This movement or vibration is haptically perceptible to the operator B via their finger resting on the actuating surface 3. The control electronics unit 21, together with the force sensor 7, is arranged on a circuit board 8, which is fixed to the carrier 20.

[0040] Furthermore, the actuating element 2 has an opening 11 in which a manually operable electronic or electromechanical input element 11, such as a rotary switch or a roller switch preferably operated with the thumb of the hand resting on the steering wheel rim, is arranged. The actuating surface 3 also includes at least one backlit illuminating surface 18, which reproduces the shape and / or outline of a symbol. At least one layer 2c of the layer structure 2a, 2b, 2c forms a recess or opening to create a light channel 12, in order to direct light from a light source 19, fixed to the carrier 20 and arranged on the circuit board 8, to the backlit illuminating surface 18. For example, the layer structure remaining in the area of ​​the illuminating surface 18 is translucent.This is achieved, for example, by providing the foil 2a or the highly elastic layer 2b with an opaque coating that is missing or has been removed in the area of ​​the luminous surface 18.

[0041] The Figure 2 and 3 show an arrangement from control element 1 of the Figure 1 and a motor vehicle steering wheel 17, wherein the operating element is arranged in the area of ​​a spoke 16 of the motor vehicle steering wheel 17 extending between the steering wheel rim 15 and a steering wheel hub. The actuating part 2 is integrally formed over the edge region 5 with a cover 13, which extends around a deflector cup 14 covering the steering wheel hub. The carrier 20 made of Figure 1 and aperture 1 are rigidly connected to each other via a locking mechanism. Figure 3 is the corresponding rear view of the actuating part 2 and the aperture 13.

Claims

1. Operating element (1), comprising: a carrier (20); an actuating part (2), which has an actuation surface (3) facing an operator (B) for making an operating input by the operator (B) and the actuating part (2) further has an edge region (5) provided outside the actuation surface (3), via which the actuating part (2) is supported on the carrier (20); wherein the actuating part (2) has a layer structure (2a, 2b, 2c) defining the actuation surface (3), such as a film layer structure, and the layer structure (2a, 2b, 2c) has at least two layers (2b, 2c) each made of a thermoplastic, and the two layers (2b, 2c) differ in the modulus of elasticity; wherein in a transition region (4) between the edge region (5) and the actuation surface (3) that layer, referred to as highly elastic layer (2b), having the smallest modulus of elasticity of the two layers, has the greatest layer thickness measured in a direction (R) perpendicular to the actuation surface (3) in comparison with a layer thickness of the other layers (2a, 2c) of the layer structure (2a, 2b, 2c) in the transition region, in order to provide an elastic compliance of the actuating part (2) in a direction (R) perpendicular to the actuation surface (3); wherein in the transition region (4) a material weakening (10) at least sectionally surrounding the actuation surface (3) is formed in the layer structure (2a, 3b, 2c); a force sensor (7) arranged between the carrier (20) and the actuating part (2) in order to detect a displacement of the actuating part (2) in the direction (R) perpendicular to the actuation surface (3), characterized in that the force sensor (7) is a contactlessly detecting force sensor and that the operating element (1) has an actuator (6) for vibration and / or motion excitation of the actuating part (2) and thus for generating active haptic feedback, which is arranged between the carrier (20) and the actuating part (2), wherein the actuator (6) is exclusively fixed to the actuating part (2) by force fit or material bond.

2. Operating element (1) according to claim 1, wherein in the transition region (4) a high-strength layer (2c) having the highest modulus of elasticity of the plurality of layers of the layer structure is removed and at least the highly elastic layer (2b) remains.

3. Operating element (1) according to the preceding claim, wherein the material weakening (10) is formed by a groove provided on the side of the actuating part (2) facing away from the operator (B).

4. Operating element (1) according to one of the preceding claims, wherein the high-strength layer (2c) having the highest modulus of elasticity of the plurality of layers of the layer structure extends substantially parallel to the actuation surface (3).

5. Operating element (1) according to one of the preceding claims, wherein the highly elastic layer (2b) is formed from a thermoplastic elastomer, such as a thermoplastic polyurethane, or a thermoplastic vulcanizate, such as a vulcanizate having an ethylene-propylene-diene rubber.

6. Operating element (1) according to one of the preceding claims, wherein the highly elastic layer (2b) has a Shore A hardness in the range of more than 55 to less than 95, preferably in the range of 65 to 85.

7. Operating element (1) according to one of the preceding claims, wherein the layer structure (2a, 2b, 2c) is a film layer structure comprising a film (2a), such as a polycarbonate film.

8. Operating element (1) according to the preceding claim, wherein the film (2a) is an outer layer of the layer structure (2a, 2b, 2c) forming the actuation surface (3).

9. Operating element (1) according to the preceding claim, wherein the film (2a) forms a common visible surface extending over the actuation surface (3), the transition region (4) and the edge region (5).

10. Arrangement comprising an operating element (1) according to one of the preceding claims and a motor vehicle steering wheel (17), wherein the operating element (1) is arranged in the region of a spoke (16) of the motor vehicle steering wheel (17) extending between a steering wheel rim (15) and a steering wheel hub.

11. Arrangement according to the preceding claim, wherein the actuating part (2) is formed integrally with a trim panel (13) which extends around an airbag cover (14) covering the steering wheel hub.

12. Arrangement according to one of the two preceding claims, wherein the actuating part (2) has an opening (11) in which a manually operable electronic or electromechanical input part (9) is arranged.

13. Use of the operating element (1) according to one of the preceding claims 1 to 9 in a motor vehicle.