CAPACITIVE SENSOR UNIT

Abstract

A capacitive sensor unit of a motor vehicle, having a first electrode, and having a second electrode which are connected to an evaluation unit. The two electrodes are connected to one another by a predetermined break point.

Claims

1. A capacitive sensor unit of a motor vehicle, comprising: a first electrode, and having a second electrode which are connected to an evaluation unit, wherein the first and second electrodes are connected to one another by a predetermined break point.

2. The capacitive sensor unit as claimed in claim 1, wherein the first and second electrodes are connected to one another in a materially joined fashion.

3. The capacitive sensor unit as claimed in claim 2, wherein the first and second electrodes are pliable, and wherein the predetermined break point is formed by perforation.

4. The capacitive sensor unit as claimed in claim 3, wherein a tearing aid adjoins the end side of the perforation.

5. The capacitive sensor unit as claimed in claim 2, wherein the first and second electrodes each have an extruded plastic carrier, and wherein the predetermined break point is formed by an adhesive layer.

6. The capacitive sensor unit of claim 1, wherein the first and second electrodes extend along a main direction of extent, and wherein the predetermined break point is parallel to the main direction of extent.

7. The capacitive sensor unit of claim 1, wherein each electrode has an electrical conductor which is soldered to a circuit board of the evaluation unit.

8. The capacitive sensor unit as claimed in claim 7, wherein the electrical conductor is loop-shaped.

9. A method for manufacturing an assembly of a motor vehicle with a capacitive sensor unit comprising: connecting a first electrode and a second electrode of the capacitive sensor unit to an evaluation unit; connecting a first and second electrode to a predetermined break point; detaching the first electrode from the second electrode; connecting the first electrode to a carrier; and the second electrode is connected to the carrier.

10. The method as claimed in claim 9, wherein the evaluation unit is connected to the carrier.

11. A capacitive sensor unit, comprising: a first electrode; and a second electrode connected to an evaluation unit, wherein the first and second electrode are connected via a predetermined break point that includes an adhesive layer running along sides of a plastic carrier of the capacitive sensor unit.

12. The capacitive sensor unit of claim 11, wherein the first electrode is connected to a circuit board via a first conductor and the second electrode is connected to a circuit board via a second conductor.

13. The capacitive sensor unit of claim 11, wherein the first and second electrode is connected to a circuit board via a conductor.

14. The capacitive sensor unit of claim 13, wherein the circuit board includes one or more connection pads.

15. The capacitive sensor unit of claim 13, wherein, the predetermined break point is parallel to a main direction of extent of the capacitive sensor unit.

16. The capacitive sensor unit of claim 11, wherein the first and second electrode are arranged on a single plane.

17. The capacitive sensor unit of claim 11, wherein the first and second electrode are ribbon cable elements.

18. The capacitive sensor unit of claim 11, wherein the first and second electrode are ribbon cable elements.

19. The capacitive sensor unit of claim 11, wherein the evaluation unit is configured to measure data made available by the first and second electrodes.

20. The capacitive sensor unit of claim 11, wherein the plastic carrier includes one or more grooves holding one or more stranded conductors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Exemplary embodiments of the disclosure are explained in more detail below with reference to a drawing, in which:

[0039] FIG. 1 shows a simplified schematic view of a tailgate which is operated by electric motor and has a capacitive sensor unit,

[0040] FIGS. 2 and 3 each show in a plan view a first embodiment of the capacitive sensor unit,

[0041] FIGS. 4 and 5 each show in a plan view a second embodiment of the capacitive sensor unit,

[0042] FIG. 6 shows a method for manufacturing an assembly of a motor vehicle, and

[0043] FIG. 7 shows a perspective view of the assembly with the capacitive sensor unit.

[0044] Parts which correspond to one another are provided with the same reference symbols in all the figures.

DETAILED DESCRIPTION

[0045] As required, detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

[0046] FIG. 1 is a schematically simplified illustration of a motor vehicle 2 with an (electromotive) adjustment drive 4 in the form of a tailgate which is operated by electric motor. The tailgate 4 which is operated by electric motor has a flap 6 which is pivotably mounted on bodywork 10 of the motor vehicle 2 by a hinge 8. The tailgate 4 which is operated by electric motor also comprises an electric motor 12 which is also fastened to the bodywork 10. A length-variable activation part 14, such as a spindle or a cylinder, is driven by the electric motor 12 and is fastened at one end to the flap 6 and at the other to the bodywork 10. Consequently, the flap 6 can be pivoted from an open position into a closed position and from a closed position into an open position by operation of the electric motor 12. The electric motor 12 is controlled by a control unit 16 which is connected by signaling technology and electrically to the electric motor 12. In this context, the energization of the electric motor 12 is set by the control unit 16.

[0047] In addition, the tailgate 4 which is operated by electric motor comprises a capacitive sensor unit 18 which is fastened to the inside of an outer skin 19 of a rear bumper 20 of the bodywork 10. The capacitive sensor unit 18 is coupled by signal technology to the control unit 16 and operates according to a capacitive principle. In so far as a user 22 moves his foot in the region of the bumper 20, wherein the foot remains spaced apart from the bodywork 10, this is sensed by the capacitive sensor unit 18 on the basis of a change in the dielectric constant in the surroundings of the bumper 20. This sensor signal is evaluated by the control unit 16 and interpreted as a user input or user request. Subsequent to this, the electric motor 12 is energized, with the result that the flap 6 is pivoted. In other words, the capacitive sensor unit 18 serves for contactless activation of the tailgate 4 which is operated by electric motor.

[0048] FIG. 2 and FIG. 3 each show a plan view of the capacitive sensor unit 18, wherein different configurations are illustrated in the two figures. FIG. 2 shows the capacitive sensor unit 18 after its fabrication and FIG. 3 shows the capacitive sensor unit 18 before its installation and fastening to the outer skin 19 of the bumper 20. The capacitive sensor unit 18 has a first electrode 24 and a second electrode 26 which each have an extruded plastic carrier 28. The two plastic carriers 28 are identical in design and have a plurality of openings 29 for mounting on the outer skin 19. The plastic carriers 28 and therefore also the electrodes 24, 26 extend along a main direction of extent 30 and are connected to one another by a predetermined break point 32. The predetermined break point 32 is an adhesive layer 34 which runs along the sides, facing one another, of the plastic carriers 28 and is parallel to the main direction of extent 30. In this context, the main direction of extent 30 is also the direction along which the plastic carriers 28 were extruded and along which the plastic carriers 28 have the greatest extent. In summary, the two electrodes 24, 26 are connected to one another in a materially joined fashion.

[0049] Each of the plastic carriers 28 has a plurality of grooves 36 within each of which a stranded conductor 38 which is positioned in the form of a loop is arranged. The stranded conductor 38 is therefore an electrical conductor 40. The electrical conductor 40 is positioned in the form of a loop, wherein two loops are formed. The electrical conductor 40 therefore ends in each case on a single side of the plastic carrier 28. The ends of the electrical conductors 40 are each soldered to connection pads 42 of the circuit board 44. The circuit board 44 has a base body which is fabricated from a glass-fiber-reinforced epoxy resin to which conductor tracks, for example made of copper, are connected. The circuit board 44 also comprises further electrical and/or electronic components 46 which are placed in electrical contact with the connection pads 42 by the conductor tracks (not illustrated in more detail). The circuit board 44 and the electrical and/or electronic components 46 are a component of an evaluation unit 47 by which the measurement data which is made available by the electrodes 24, 26 is evaluated during operation. In summary, the two electrodes 24, 26 are connected to the evaluation unit 47 by signaling technology and electrically and mechanically.

[0050] In order to mount the capacitive sensor unit 18, the predetermined break point 32 is disconnected so that the two electrodes 24, 26 can be spaced apart from one another, as is shown in FIG. 3. It is also possible here to pivot the main direction of extent 30 of the two electrodes 24, 26 with respect to one another owing to the elastic/plastic deformability of the stranded conductors 38, with the result that they are no longer arranged parallel to one another. Here, the stranded conductors 38 also continue to be held within the plastic carriers 28 by the grooves 36.

[0051] FIGS. 4 and 5 show an alternative configuration of the capacitive sensor unit 18 corresponding to FIGS. 2 and 3. This embodiment also has the first and second electrodes 24, 26 which are fastened to one another by the predetermined break point 32. In this context, the first electrode 24 and the second electrode 26 are configured as a flexible circuit board and are therefore pliable. The electrical conductor 40 is implemented by a conductor track 50 which is printed onto a foil 48. The predetermined breaking point 32 is formed by a perforation 52. In other words, the foil 48 is perforated in the region of the predetermined break point 32. The perforation 52 itself runs in turn along the main direction of extent 30 and opens, at one end, into a tearing aid 54 which therefore adjoins the perforation 52 at one end. The two electrodes 24, 26 are configured to have axial symmetry with respect to the predetermined break point 32, that is to say with respect to the perforation 52.

[0052] The evaluation unit 47 is, on the other hand, not modified and has in turn the electrical and/or electronic components of the circuit board 44. The conductor tracks 50 of the two electrodes 24, 26 are also in electrical contact with the connection pads 42 of the circuit board 44. Consequently, the electrical conductor 40 in the form of the conductor track 50 of the respective electrodes 24, 26 is in turn soldered to the circuit board 44 of the evaluation unit 47. The electrical conductor 40 is in turn configured in the form of a loop, wherein in this exemplary embodiment in each case just a single loop is present. In a configuration of the disclosure which is not illustrated in more detail, the circuit board 44 is also configured as a flexible circuit board and in one piece with the electrodes 24, 26 and consequently also has the foil 48. In this case, the conductor tracks 50 are essentially connected integrally to the circuit board 44.

[0053] In order to mount the capacitive sensor unit 18, the perforation 52 is separated, for which the tearing aid 54 is used. For example, a blade or the like is inserted into the tearing aid 54 and moved along the main direction of extent 30 with respect to the electrodes 24, 26. It is therefore possible to space apart the two electrodes 24, 26 perpendicularly with respect to the main direction of extent 30, as shown in FIG. 5. Therefore, two strips of the foil 48 are now present. The fastening to the outer skin 19 of the bumper 20 takes place by the openings 29 of the two electrodes 24, 26. In this context, clips or the like are guided through the openings 29 and fastened to the outer skin 19 or to another component of the bumper 20. Owing to the pliable configuration of the electrodes 24, 26 positioning on the outer skin 19 according to requirements is possible.

[0054] FIG. 6 illustrates a method 56 for manufacturing the bumper 20 which is an assembly of the motor vehicle 2 and which is shown in schematically simplified form from the inner side in FIG. 7. The method 56 can also be used here for fabricating a door module or the like. In a first working step 58, the capacitive sensor unit 18 is made available with the first electrode 24 and with the second electrode 26 which are connected to the evaluation unit 47. In this context, the two electrodes 24, 26 are connected to one another by the predetermined break point 32. The outer skin 19 is made available in a second working step 60 which takes place, for example, simultaneously, said outer skin 19 therefore forming a carrier. The outer skin 19 is an injection-molded a plastic part which is provided on the outside with a surface coating.

[0055] In a subsequent third working step 62, the first electrode 24 is detached from the second electrode 26, and the predetermined break point 32 is therefore separated. In a directly subsequent fourth working step 64, the first electrode 24 and the second electrode 26 are connected to the inner side of the outer skin 19. For this purpose, clips which are not illustrated in more detail are guided through the openings 29 and fastened to the outer skin 19. In a subsequent fifth working step 66, the evaluation unit 47 is also fastened to the inner side of the outer skin 19.

[0056] In summary, the electrodes 24, 26 are ribbon cable elements. These are not connected to one another individually, but rather longitudinally, that is to say along the main direction of extent 30, via the predetermined break point 32. Therefore, the two electrodes 24, 26 can be used as one part and be disconnected directly before or during the mounting on the carrier 19. For example, a slightly adhesive intermediate substrate, in particular glue, is introduced between the two electrodes 24, 26, with the result that the two electrodes 24, 26 can be separated on an assembly line of the bumper 20.

[0057] Owing to the capacitive sensor unit 18, simplified handling is provided since the electrodes 24, 26 do not snag on one another and there are few degrees of freedom in the geometry of the capacitive sensor unit 18. In this way, a machine process is possible which provides reproducible precision. An accelerated handling owing to the temporary reduction of the movable parts is provided since the two electrodes 24, 26 are stabilized with respect to one another.

[0058] Owing to the tearing aid 54, disconnection of the electrodes 24, 26 which are ribbon cable elements at the predefined point, that is to say along the predetermined break point 32, is facilitated. The start of the predetermined break point 32, that is to say the start of the intended tear, is therefore also marked. The predetermined break point 32 is separated, for example, by pulling and/or shearing, and the two electrodes 24, 26 may be mounted separately. In a further configuration, a plurality of capacitive sensor units 18 are present which are present as a roller or matt. In this context, all the electrodes 24, 26 are connected to one another and may be made available by a single matt or a single roller. The main direction of extent 30 of the electrodes 24, 26 is perpendicular to the main direction of extent of the matt/parallel to the axis of the roller here. The individual capacitive sensor units 18 are produced by disconnecting the matt/roller. The respective electrodes 24, 26 may be connected to one another by a further predetermined break point, between respectively adjacent capacitive sensor units 18.

[0059] The invention is not limited to the exemplary embodiments described above. Instead, other variants of the invention can also be derived therefrom by a person skilled in the art without departing from the subject matter of the invention. In addition, in particular all the individual features described in conjunction with the individual exemplary embodiments can also be combined with one another in some other way without departing from the subject matter of the invention.

[0060] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

LIST OF REFERENCE NUMBERS

[0061] 2 Motor vehicle [0062] 4 Adjustment drive [0063] 6 Flap [0064] 8 Hinge [0065] 10 Bodywork [0066] 12 Electric motor [0067] 14 Length variable activation part [0068] 16 Control unit [0069] 18 Capacitive sensor unit [0070] 19 Outer skin [0071] 20 Bumper [0072] 22 User [0073] 24 First electrode [0074] 26 Second electrode [0075] 28 Plastic carrier [0076] 29 Opening [0077] 30 Main direction of extent [0078] 32 Predetermined break point [0079] 34 Adhesive layer [0080] 36 Groove [0081] 38 Stranded conductor [0082] 40 Electrical conductor [0083] 42 Connection pad [0084] 44 Circuit board [0085] 46 Electrical/electronic component [0086] 47 Evaluation unit [0087] 48 Foil [0088] 50 Conductor track [0089] 52 Perforation [0090] 54 Tearing aid [0091] 56 Method [0092] 58 First working step [0093] 60 Second working step [0094] 62 Third working step [0095] 64 Fourth working step [0096] 66 Fifth working step