Contact detecting device

Abstract

According to the present invention, if an occupant grips a rim portion of a steering wheel, and the capacitance between the occupant and an electrically conductive cloth on the rim portion is equal to or greater than a predetermined capacitance, a control device detects that the occupant is gripping the rim portion. Here, a terminal portion is electrically connected to the electrically conductive cloth from the reverse side, and the electrically conductive cloth is connected to the control device via the terminal portion. As a result, the electrically conductive cloth can be easily connected to the control device.

Description

Contact Detection Device

[0001] The present invention relates to a contact detection device that detects contact of an occupant with a steering wheel.

[0002] In the steering wheel described in JP 2016-165940 A, contact of the rim portion with the occupant is detected by the detection board based on the electrostatic capacitance between the occupant touching the rim portion and the conductive layer of the rim portion.

[0003] Here, in this steering wheel, the terminal portion of the conductive layer is connected to the detection board.

[0004] In consideration of the above, an object of the present invention is to provide a contact detection device in which the detection electrodes can be easily connected to the detection units.

[0005] A first aspect of the contact detection device of the present invention includes a steering wheel that is touched and operated by an occupant to steer a vehicle, a detection electrode provided on the steering wheel, a terminal portion that is electrically connected to the detection electrode from the back side, and a detection portion to which the detection electrode is connected via the terminal portion, which detects the occupant's contact with the steering wheel based on the electrostatic capacitance between the occupant touching the steering wheel and the detection electrode.

[0006] A contact detection device according to a second aspect of the present invention is the contact detection device according to the first aspect of the present invention, wherein the terminal portions sandwich the detection electrodes.

[0007] A third aspect of the contact detection device of the present invention is a contact detection device of the first or second aspect of the present invention, which comprises an outer periphery layer that forms the outer periphery of the steering wheel, an adhesive layer that bonds the detection electrode and the outer periphery layer, and a limiting layer that is provided at the terminal portion arrangement position of the detection electrode and limits the adhesion between the detection electrode and the outer periphery layer by the adhesive layer.

[0008] A contact detection device according to a fourth aspect of the present invention is the contact detection device according to any one of the first to third aspects of the present invention, further comprising an outer periphery layer that forms the outer periphery of the steering wheel and on which the terminal portion is not provided.

[0009] A fifth aspect of the contact detection device of the present invention is a contact detection device according to any one of the first to fourth aspects of the present invention, comprising an outer periphery layer that forms the outer periphery of the steering wheel and is formed by connecting a plurality of components at connecting parts, and a recess that is provided on the steering wheel and into which the connecting parts and the detection electrodes are inserted with the detection electrodes arranged along the connecting parts.

[0010] In the contact detection device of the first aspect of the present invention, a vehicle is steered by an occupant touching the steering wheel and operating the steering wheel. The detection electrode of the steering wheel is connected to a detection unit, and the detection unit detects the occupant's contact with the steering wheel based on the electrostatic capacitance between the occupant touching the steering wheel and the detection electrode.

[0011] Here, the terminal portion is electrically connected to the detection electrode from the rear side, and the detection electrode is connected to the detection portion via the terminal portion, so that the detection electrode can be easily connected to the detection portion.

[0012] In the contact detection device according to the second aspect of the present invention, the terminal portion sandwiches the detection electrode, thereby enabling the terminal portion to be appropriately electrically connected to the detection electrode.

[0013] In the contact detection device according to the third aspect of the present invention, the outer periphery of the steering wheel is formed by an outer periphery layer, and the detection electrode and the outer periphery layer are bonded by an adhesive layer.

[0014] The limiting layer at the position where the terminal of the detection electrode is disposed limits the adhesion between the detection electrode and the outer peripheral layer by the adhesive layer, and therefore the limiting layer can increase the rigidity at the position where the terminal of the detection electrode is disposed.

[0015] In the contact detection device according to the fourth aspect of the present invention, the outer periphery of the steering wheel is formed by the outer periphery layer, and no terminal portion is provided on the outer periphery layer, which prevents the terminal portion from interfering with the assembly of the outer periphery layer.

[0016] In a fifth aspect of the contact detection device of the present invention, an outer periphery of the steering wheel is formed by an outer periphery layer, and the outer periphery layer is formed by connecting a plurality of components at connecting portions. Furthermore, the connecting portions and the detection electrodes are inserted into recesses in the steering wheel with the detection electrodes arranged along the connecting portions. This prevents an air gap from being formed between the connecting portions and the detection electrodes, thereby improving the accuracy of the capacitance between the detection electrodes and an occupant who comes into contact with the connecting portions of the outer periphery layer.

[0017] FIG. 1 is a front view showing a steering wheel according to a first embodiment of the present invention, as seen from the front side. FIG. 2 is a development view showing a cover body of the steering wheel according to the first embodiment of the present invention, as seen from the back side. FIG. 3 is a cross-sectional view (cross-sectional view taken along line 2B-2B in FIG. 1) of the steering wheel according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a cover body of the steering wheel according to the first embodiment of the present invention. FIG. 5 is a perspective view showing an assembly state of the steering wheel according to the first embodiment of the present invention, as seen from diagonally above right. FIG. 6 is a cross-sectional view showing a cover body of the steering wheel according to a second embodiment of the present invention.

[0018] 1 shows a front view of a steering wheel 10 according to a first embodiment to which a contact detection device of the present invention is applied. In the drawing, the front of the steering wheel 10 is indicated by an arrow FR, the upper side of the steering wheel 10 is indicated by an arrow UP, the right side of the steering wheel 10 is indicated by an arrow RH, and the circumferential direction of the steering wheel 10 is indicated by an arrow C.

[0019] The steering wheel 10 according to this embodiment faces the front of the driver's seat of the vehicle, and is disposed in front of the occupant (driver) seated in the driver's seat. The front, upper, and right sides of the steering wheel 10 are directed obliquely upward and rearward, obliquely upward and frontward, and rightward, respectively, of the vehicle.

[0020] 1, the central portion of the steering wheel 10 is a boss portion 10A, and the peripheral portion of the steering wheel 10 is a rim portion 10B that serves as a grip portion and is annular in front view and circular in cross section. Three spoke portions 10C are provided between the boss portion 10A and the rim portion 10B as connecting portions, and the spoke portions 10C extend leftward, rightward, and downward from the boss portion 10A and are connected to the rim portion 10B.

[0021] The boss portion 10A is fixed to the rear end (upper end) of a cylindrical steering shaft 12 serving as a support member for the vehicle, and the steering shaft 12 is disposed coaxially with the rim portion 10B. The steering wheel 10 is supported by the steering shaft 12 so as to be rotatable integrally with it, and when an occupant grips the rim portion 10B and rotates the steering wheel 10 in the circumferential direction, the steering shaft 12 rotates about the central axis, thereby steering the vehicle.

[0022] The inner periphery of rim portion 10B is made of polyurethane and is constituted by a rim base material 14 (see Figure 4). Grooves 14A (see Figure 2B) with a rectangular cross section are formed as recesses on the outer periphery of rim base material 14 in the upper left, lower left, upper right, and lower right sections, and grooves 14A are open to the outside of the outer periphery of rim base material 14 and are arranged all around the periphery of rim portion 10B (the direction around the periphery of steering wheel 10).

[0023] An annular, band-shaped cover body 16 (see FIGS. 2A, 3 and 4) is attached to the outer periphery of the rim base material 14 , and the cover body 16 covers the outer periphery of the rim base material 14 .

[0024] The cover body 16 is provided with an annular, strip-shaped leather 18 as an outer peripheral layer. The leather 18 forms the outer periphery of the rim portion 10B and is an insulator. The leather 18 is composed of multiple (four in this embodiment) generally rectangular pieces 18A as constituent materials, and the multiple pieces 18A are connected in an annular shape. Ends of the pieces 18A are folded toward the back of the leather 18 and connected by sewing in an overlapping state (see FIG. 2B ). A connecting portion 18B between the pieces 18A is formed by the ends of a pair of pieces 18A. The leather 18 is wrapped around the rim base material 14 in the circumferential direction of the steering wheel 10 and the rim portion 10B, and both widthwise ends (both ends on the inner circumferential side of the steering wheel 10) are connected by sewing to be assembled to the rim base material 14. The connecting portion 18B of the leather 18 is inserted into a groove 14A of the rim base material 14.

[0025] A plurality of (two in this embodiment) long rectangular sheets of conductive cloth 20 are provided on the back side of the leather 18 as detection electrodes. The conductive cloth 20 is made of conductive cloth (woven fabric). The conductive cloth 20 extends in the circumferential direction of the leather 18, and is disposed on the rim portions 10B on both the left and right sides of the steering wheel 10.

[0026] Double-sided tape 22 is adhered to the front side of the conductive cloth 20 as an adhesive layer, and the double-sided tape 22 is made of an insulator. The front side of the double-sided tape 22 is adhered to the back side of the leather 18, and the double-sided tape 22 adheres the conductive cloth 20 to the leather 18. The conductive cloth 20 is adhered to the leather 18 with the double-sided tape 22 before the leather 18 is assembled to the rim base material 14, and at the position of the connecting portion 18B of the leather 18, the conductive cloth 20 is arranged along the connecting portion 18B (see FIG. 2B ). The conductive cloth 20 is assembled by wrapping it around the rim base material 14 together with the leather 18, and the conductive cloth 20 is inserted into the groove 14A of the rim base material 14 together with the connecting portion 18B.

[0027] A protrusion 20A is provided at one longitudinal end of the conductive cloth 20 (the end on the lower side of the steering wheel 10), and the protrusion 20A protrudes toward one widthwise side of the conductive cloth 20 (the rear side of the steering wheel 10), and thus toward one widthwise side of the leather 18. On the front side of the protrusion 20A, a release paper 22A remains as a limiting layer on the front side of the double-sided tape 22, and the release paper 22A limits the adhesion of the double-sided tape 22 of the protrusion 20A to the leather 18 and also serves as an insulator. A circular insertion hole 24 is formed through the protrusion 20A, and the insertion hole 24 also passes through the double-sided tape 22 and the release paper 22A.

[0028] The protrusion 20A is provided with a terminal 26. The terminal 26 is provided with a metal rivet 28 serving as an engaging member, with the leg of the rivet 28 inserted into the insertion hole 24 and the head of the rivet 28 positioned on the front side of the release paper 22A. A metal round terminal 30 serving as a terminal is provided on the back side of the protrusion 20A, with the leg of the rivet 28 inserted into the annular plate-shaped tip of the round terminal 30. A metal, approximately annular plate-shaped push nut 32 serving as a locking member is provided on the side of the round terminal 30 opposite the protrusion 20A, with the leg of the rivet 28 passing through the push nut 32. The push nut 32 is elastically engaged with the leg of the rivet 28, thereby preventing the push nut 32 from moving away from the round terminal 30. The round terminal 30, the protrusion 20A, the double-sided tape 22 and the release paper 22A are sandwiched between the push nut 32 and the head of the rivet 28, and the round terminal 30 is in contact with the protrusion 20A from the back side, thereby establishing electrical continuity.

[0029] A harness 34 is connected to the base end of the round terminal 30, and the harness 34 is connected to a control device 36 (ECU) that serves as a detection unit. Therefore, the conductive cloth 20 is connected to the control device 36 via the terminal portion 26 (round terminal 30) and the harness 34. In addition, the protruding portion 20A of the conductive cloth 20 (including the double-sided tape 22, the release paper 22A, the terminal portion 26, and the harness 34) is covered and protected by a protective tape 38.

[0030] Next, the operation of this embodiment will be described.

[0031] In the steering wheel 10 configured as described above, when an occupant grasps the rim portion 10B and the capacitance between the occupant's hand and the conductive cloth 20 of the cover body 16 on the rim portion 10B is equal to or greater than a predetermined capacitance, the control device 36 detects the occupant's grasping (contact) of the rim portion 10B.

[0032] Here, the round terminal 30 of the terminal portion 26 is electrically connected to the protruding portion 20A of the conductive cloth 20 from the back side, and the conductive cloth 20 is connected to the control device 36 via the terminal portion 26 and the harness 34. Therefore, the conductive cloth 20 can be easily connected to the control device 36.

[0033] Furthermore, in the terminal portion 26, the conductive cloth 20 is sandwiched between the round terminal 30 and the head of the rivet 28. Therefore, the round terminal 30 can be appropriately electrically connected to the conductive cloth 20.

[0034] Furthermore, the release paper 22A remains on the protruding portion 20A (position of the terminal portion 26) of the conductive cloth 20. Therefore, the release paper 22A can increase the rigidity of the protruding portion 20A of the conductive cloth 20, and the terminal portion 26 (rivet 28, round terminal 30, and push nut 32) can be easily assembled to the protruding portion 20A.

[0035] Furthermore, in the cover body 16, no other conductive cloth or insulator between the conductive cloths is provided on the back side of the conductive cloth 20. This allows the cover body 16 to be made thin, the rigidity of the cover body 16 to be reduced, and the cover body 16 can be easily wrapped around and assembled to the rim base material 14 of the rim portion 10B.

[0036] Furthermore, in the cover body 16, the leather 18 is not provided with the terminal portion 26. Therefore, it is possible to prevent the terminal portion 26 from interfering with the assembly (wrapping) of the leather 18 onto the rim base material 14.

[0037] Furthermore, with the conductive cloth 20 positioned along the connecting portion 18B between the pieces 18A of the leather 18, the connecting portion 18B and the conductive cloth 20 are inserted into the groove 14A of the rim base material 14. This prevents an air layer from being formed between the connecting portion 18B and the conductive cloth 20, increasing the accuracy of the capacitance between the conductive cloth 20 and an occupant gripping the connecting portion 18B of the leather 18, and increasing the accuracy of detecting the occupant's grip on the rim portion 10B. Moreover, the connecting portion 18B and the conductive cloth 20 can be appropriately inserted into the groove 14A, preventing the leather 18 from being protruded by the connecting portion 18B and the conductive cloth 20 and deteriorating the appearance of the leather 18.

[0038] Second Embodiment FIG. 5 shows a cross-sectional view of a cover body 16 of a steering wheel 50 according to a second embodiment to which a contact detection device of the present invention is applied.

[0039] The steering 50 according to this embodiment has almost the same configuration as that of the first embodiment, but differs in the following respects.

[0040] As shown in FIG. 5, in the steering wheel 50 according to this embodiment, a long rectangular sheet-shaped heater 52 is provided as a heating mechanism on the back side of the conductive cloth 20, excluding the protruding portion 20A. The heater 52 extends in the circumferential direction of the leather 18, and an electric heating wire (not shown) is provided by printing.

[0041] Double-sided tape 54 is adhered to the front side of the heater 52 as an additional adhesive layer, and the double-sided tape 54 is made of an insulator. The front side of the double-sided tape 54 is adhered to the back side of the conductive cloth 20, and the double-sided tape 54 adheres the heater 52 to the leather 18 and the conductive cloth 20. The heater 52 is adhered to the conductive cloth 20 with the double-sided tape 54 before the leather 18 and the conductive cloth 20 are assembled to the rim base material 14, and at the position of the connecting portion 18B of the leather 18, the conductive cloth 20 and the heater 52 are arranged along the connecting portion 18B. The heater 52, together with the leather 18 and the conductive cloth 20, is wrapped around and assembled to the rim base material 14 of the rim portion 10B, and the heater 52, together with the connecting portion 18B and the conductive cloth 20, is inserted into the groove 14A of the rim base material 14.

[0042] A harness 56 is connected to the heater 52 (heating wire), and the harness 56 is connected to the control device 36. Therefore, the heater 52 is connected to the control device 36 via the harness 56.

[0043] Here, this embodiment can also achieve the same functions and effects as the first embodiment.

[0044] Furthermore, current is supplied to the heater 52 (heating wire) under the control of the control device 36, causing the heater 52 (heating wire) to generate heat, thereby allowing the heater 52 to heat the rim portion 10B.

[0045] Furthermore, the conductive cloth 20 and the heater 52 are arranged along the connecting portion 18B of the leather 18. This allows the connecting portion 18B, the conductive cloth 20, and the heater 52 to be properly inserted into the groove 14A of the rim base material 14, preventing the leather 18 from being protruded by the connecting portion 18B, the conductive cloth 20, and the heater 52, thereby preventing the appearance of the leather 18 from being deteriorated.

[0046] In the first and second embodiments, the release paper 22A of the double-sided tape 22 remains on the protruding portion 20A of the conductive cloth 20. However, the release paper 22A of the double-sided tape 22 does not have to remain on the protruding portion 20A of the conductive cloth 20.

[0047] The disclosure of Japanese Patent Application No. 2023-171479, filed on October 2, 2023, is incorporated herein by reference in its entirety.

[0048] 10: Steering wheel, 14A: Groove (recess), 18: Leather (outer peripheral layer), 18A: Piece (component), 18B: Connecting portion, 20: Conductive cloth (detection electrode), 22: Double-sided tape (adhesive layer), 22A: Release paper (limiting layer), 26: Terminal portion, 36: Control device (detection portion), 50: Steering wheel

Claims

1. A contact detection device comprising: a steering wheel that is operated by an occupant to touch and steer a vehicle; a detection electrode provided on the steering wheel; a terminal portion that is conductive to the detection electrode from the back side; and a detection portion to which the detection electrode is connected via the terminal portion, the detection device detecting the contact of the occupant with the steering wheel based on the electrostatic capacitance between the occupant touching the steering wheel and the detection electrode.

2. A contact detection device according to claim 1, wherein said terminal portion sandwiches said detection electrode.

3. A contact detection device as described in claim 1 or claim 2, comprising: an outer periphery layer that forms the outer periphery of the steering wheel; an adhesive layer that bonds the detection electrode and the outer periphery layer; and a limiting layer that is provided at the position where the terminal portion of the detection electrode is located and that limits the adhesion between the detection electrode and the outer periphery layer by the adhesive layer.

4. The contact detection device according to claim 3, wherein said adhesive layer is a double-sided tape and said limiting layer is a release paper.

5. A contact detection device according to any one of claims 1 to 4, further comprising an outer periphery layer that constitutes the outer periphery of the steering wheel and on which the terminal portion is not provided.

6. A contact detection device as claimed in any one of claims 1 to 5, wherein the terminal portion comprises: an engaging member that engages with the detection electrode from the front side and is penetrated by the detection electrode; a terminal that is conductive to the detection electrode and is penetrated by the engaging member; and a locking member that engages with the engaging member and locks the terminal from the back side.

7. A contact detection device according to any one of claims 1 to 6, further comprising a heating mechanism provided on the rear side of the detection electrode for heating the steering wheel.

8. The touch detection device of claim 7, further comprising an additional adhesive layer for adhering said detection electrode and said heating mechanism.

9. A contact detection device as claimed in any one of claims 1 to 8, comprising: an outer periphery layer which constitutes the outer periphery of the steering wheel and is constituted by a plurality of components connected at connecting parts; and a recess which is provided on the steering wheel and into which the connecting parts and the detection electrodes are inserted with the detection electrodes arranged along the connecting parts.

10. A contact detection device as described in claim 9, further comprising a heating mechanism provided on the rear side of the detection electrode for heating the steering wheel, and wherein the connection portion, the detection electrode and the heating mechanism are inserted into the recess with the detection electrode and the heating mechanism positioned along the connection portion.

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