Conductive structure

Abstract

In a conductive structure (10), a resin (20B) into which a conductive material (20A) is mixed is molded to form a conductive resin (20), and the conductive resin is configured to have a low mixing density in the peripheral portion of the conductive resin. A protruding portion (28) of a terminal (26) enters the inner side from a peripheral surface of the conductive resin, and is electrically connected to the conductive material of the conductive resin. Thus, the terminal can be electrically connected to the conductive resin with a simple configuration.

Description

Conduction structure

[0001] The present invention relates to a conductive structure in which a terminal is electrically connected to a conductive resin.

[0002] In the handle described in JP 2023-119417 A, a sensor layer is formed by adding a conductive material to a urethane-based paint, and a conductive adhesive is formed by dispersing a conductive filler in an organic binder of the adhesive.

[0003] Here, in this handle, an insertion recess is provided on the peripheral surface of the sensor layer, and a conductive adhesive and a terminal are inserted into the insertion recess, and the terminal is electrically connected to the conductive material of the sensor layer via the conductive filler of the conductive adhesive.

[0004] In consideration of the above, an object of the present invention is to provide a conductive structure that can electrically connect a terminal to a conductive resin with a simple configuration.

[0005] The conductive structure of a first aspect of the present invention comprises a conductive resin formed by molding a resin mixed with a conductive material and used to detect a human body, and a terminal having a protruding portion that extends from the peripheral surface of the conductive resin to the inside and is electrically connected to the conductive material.

[0006] A second aspect of the present invention provides the conductive structure of the first aspect of the present invention, wherein the conductive material is fibrous.

[0007] A conductive structure according to a third aspect of the present invention is the conductive structure according to the first or second aspect of the present invention, wherein the terminal is provided with the protruding portion having a large protruding amount and the protruding portion having a small protruding amount.

[0008] The conductive structure of a fourth aspect of the present invention is the conductive structure of the third aspect of the present invention, wherein the protruding portion with a large protrusion amount is conductive to the conductive material, and the protruding portion with a small protrusion amount is not conductive to the conductive material.

[0009] A fifth aspect of the present invention provides the conductive structure of the third or fourth aspect of the present invention, wherein the protruding portion having a smaller protruding amount is arranged around the protruding portion having a larger protruding amount.

[0010] In the conductive structure of the first aspect of the present invention, a conductive resin is formed by molding a resin mixed with a conductive material, and the mixed density of the conductive material is reduced around the periphery of the conductive resin. Also, the conductive resin is used to detect a human body.

[0011] Here, the protruding portion of the terminal penetrates from the peripheral surface of the conductive resin to the inside and is electrically connected to the conductive material, so that the terminal can be electrically connected to the conductive resin with a simple structure.

[0012] In the conduction structure according to the second aspect of the present invention, the conductive material is fibrous, so that the protruding portion of the terminal can be properly conducted to the conductive material, and the terminal can be properly conducted to the conductive resin.

[0013] In the conductive structure of the third aspect of the present invention, the terminal is provided with a protruding portion having a large protrusion amount and a protruding portion having a small protrusion amount, so that even if the protruding portion having a large protrusion amount is provided, the protruding portion having a small protrusion amount does not reduce the strength of the conductive resin to a large extent, and the protruding portion having a small protrusion amount can firmly bond the terminal to the conductive resin.

[0014] In the conductive structure of the fourth aspect of the present invention, the protruding portions with a large protrusion amount are electrically connected to the conductive material, and the protruding portions with a small protrusion amount are not electrically connected to the conductive material. Therefore, even if the protruding portions with a small protrusion amount are provided, the protruding portions with a large protrusion amount can provide good electrical connection between the terminal and the conductive resin.

[0015] In the conductive structure of the fifth aspect of the present invention, the protruding portions with smaller protrusion amounts are arranged around the protruding portions with larger protrusion amounts, so that the terminals can be effectively bonded to the conductive resin by the protruding portions with smaller protrusion amounts.

[0016] Fig. 1 is a front view seen from the front side showing a steering wheel to which a conduction structure according to a first embodiment of the present invention is applied; Fig. 2 is a cross-sectional view showing the conduction structure according to the first embodiment of the present invention; Fig. 3 is a cross-sectional view showing a first step of a manufacturing method for the conduction structure according to the first embodiment of the present invention; Fig. 4 is a cross-sectional view showing a second step of a manufacturing method for the conduction structure according to the first embodiment of the present invention; Fig. 5 is a cross-sectional view showing a third step of a manufacturing method for the conduction structure according to the first embodiment of the present invention; Fig. 6 is a cross-sectional view showing a disassembled state of the conduction structure according to a second embodiment of the present invention; Fig. 7 is a cross-sectional view showing a combined state of the conduction structure according to the second embodiment of the present invention.

[0017] 1 shows a front view of a steering wheel 12 to which a conductive structure 10 according to a first embodiment of the present invention is applied. In the drawing, the arrow UP indicates the top of the steering wheel 12, the arrow RH indicates the right side of the steering wheel 12, and the arrow FR indicates the front of the steering wheel 12.

[0018] In this embodiment, the steering wheel 12 faces the front of the driver's seat of the vehicle, and is disposed in front of the occupant (driver, human body) seated in the driver's seat. The front, upper, and right sides of the steering wheel 12 are oriented toward the rear, upper, and right sides of the vehicle, respectively.

[0019] 1, the central portion of the steering wheel 12 is a boss portion 12A, and the peripheral portion of the steering wheel 12 is a rim portion 12B that serves as a grip portion and has a circular shape in front view and a substantially circular cross section. Three spoke portions 12C are provided between the boss portion 12A and the rim portion 12B as connecting portions, and the spoke portions 12C extend leftward, rightward, and downward from the boss portion 12A and are connected to the rim portion 12B.

[0020] The boss portion 12A is fixed to the rear end (upper end) of a cylindrical steering shaft 14 serving as a support member for the vehicle, and the steering shaft 14 is disposed coaxially with the rim portion 12B. The steering wheel 12 is supported by the steering shaft 14 so as to be rotatable integrally with it, and when an occupant grips the rim portion 12B and rotates the steering wheel 12 in the circumferential direction, the steering shaft 14 rotates about the central axis, thereby steering the vehicle.

[0021] The conductive structure 10 according to this embodiment is provided with a pair of elongated plate-shaped garnishes 16 as decorative members, and the garnishes 16 are arranged on the front side of the left and right portions of the rim portion 12B and on the inner circumferential side of the steering wheel 12. The garnishes 16 extend in the circumferential direction of the steering wheel 12, and are arranged from above the connection portion of the rim portion 12B with the left or right spoke portion 12C to the connection portion of the rim portion 12B with the lower spoke portion 12C.

[0022] The garnish 16 is fitted into a recess 18 in the main body of the rim portion 12B, and the front surface of the garnish 16 is flush with the peripheral surface of the main body of the rim portion 12B. A plate-shaped protruding plate 16A is integrally formed at the longitudinal middle portion of the garnish 16, and the protruding plate 16A protrudes toward the inner periphery of the steering wheel 12 to cover the front side of the connection portion of the left or right spoke portion 12C with the rim portion 12B. A plate-shaped convex plate 16B is integrally formed at the lower end of the garnish 16, and the convex plate 16B protrudes upward to cover the front side of the connection portion of the lower spoke portion 12C with the rim portion 12B.

[0023] The front surface (front side) of the garnish 16 (including the protruding plate 16A and the convex plate 16B) is formed with a decorative layer 16C as a decorative part (dielectric part), and the decorative layer 16C has, for example, a wood grain pattern formed thereon to decorate the steering wheel 12.

[0024] The garnish 16 (including the protruding plate 16A and the convex plate 16B) has a conductive resin 20 (see FIG. 2) as a detection portion provided on the back side of the decorative layer 16C, and the conductive resin 20 forms the end face and back side (rear side) of the garnish 16. The conductive resin 20 is formed by injection molding using a mold a resin 20B mixed with a fibrous conductive material 20A (e.g., carbon fiber). The entire peripheral portion (including the entire peripheral surface) of the conductive resin 20 has a low density of the conductive material 20A mixed in, forming a skin layer 20C as the peripheral portion (low-mixture portion). The conductive resin 20 has conductivity due to the conductive material 20A, and the skin layer 20C has a low conductivity due to the low density of the conductive material 20A mixed in. In addition, the portion of the conductive resin 20 inside the skin layer 20C is an inner portion 20D that serves as a conductive portion (high-mixture portion), and the inner portion 20D has a high mixing density of the conductive material 20A, making it highly conductive.

[0025] The conductive resin 20 is electrically connected to a control board 24 serving as a control unit via a harness 22 serving as wiring in the protruding plate 16B portion of the garnish 16. The harness 22 is routed within the lower spoke portion 12C, and the control board 24 is fixed within the boss portion 12A.

[0026] As shown in FIG. 2 , a metal, generally plate-shaped terminal 26 is provided at one end (the end on the garnish 16 side) of the harness 22. The terminal 26 is fixed to the harness 22 for electrical connection. A plurality of columnar protrusions 28 are formed on the rear surface (front surface) of the terminal 26, and the protrusions 28 protrude forward. The protrusions 28 are all the same in length, and the protrusion amounts are equal to or greater than the thickness of the skin layer 20C of the conductive resin 20. The protrusions 28 extend inward from the rear surface (rear surface, peripheral surface) of the conductive resin 20, and the rear side of the terminal 26 is joined to the rear side of the conductive resin 20, thereby connecting the terminal 26 to the conductive resin 20. The protrusions 28 penetrate the skin layer 20C of the conductive resin 20 and extend into the inner portion 20D of the conductive resin 20, thereby providing electrical connection between the protrusions 28 and the conductive material 20A of the inner portion 20D.

[0027] When the terminal 26 is bonded to the conductive resin 20, a laser 30A is irradiated in a predetermined pattern onto the backside of the terminal 26 by a laser device 30, forming recesses and thus forming multiple protrusions 28 on the backside of the terminal 26 (see FIG. 3A ). Next, the backside of the conductive resin 20 is pressed against the backside of the terminal 26 fixed to a jig by a shaft 32, and the terminal 26 is heated from the front side by an induction heating (IH) heating device 34 (see FIG. 3B ). This melts the conductive resin 20 from the backside, and immediately after the multiple protrusions 28 of the conductive resin 20 penetrate inward from the backside of the conductive resin 20 due to the pressure from the shaft 32, the conductive resin 20 is cooled, and the terminal 26 is bonded to the conductive resin 20 (see FIG. 3C ).

[0028] Next, the operation of this embodiment will be described.

[0029] In the steering wheel 12 configured as described above, the conductive resin 20 of the garnish 16 and the control board 24 are electrically connected via the terminal 26 and the harness 22, and when an occupant's hand comes into contact with the front surface of the garnish 16 (particularly when the occupant grips the rim portion 12B), the control board 24 detects that the occupant's hand has come into contact with the front surface of the garnish 16 based on the capacitance between the occupant's hand and the conductive resin 20 of the garnish 16 becoming greater than a predetermined capacitance.

[0030] The conductive resin 20 is formed by molding a resin 20B mixed with a conductive material 20A, and the density of the conductive material 20A mixed in is low in the skin layer 20C around the conductive resin 20, while the density of the conductive material 20A mixed in is high in the inner part 20D of the conductive resin 20.

[0031] Here, the protrusion 28 of the terminal 26 penetrates from the peripheral surface (back surface) of the conductive resin 20 to the inside, and is electrically connected to the conductive material 20A of the conductive resin 20. This allows the terminal 26 to be electrically connected to the conductive resin 20 with a simple configuration. Furthermore, this eliminates the need to remove the skin layer 20C from the conductive resin 20 to electrically connect the terminal 26 to the conductive resin 20, and also eliminates the need to bond the terminal 26 to the conductive resin 20 with an adhesive (and also eliminates the need to cure the adhesive). This reduces the number of steps required to electrically connect the terminal 26 to the conductive resin 20, thereby reducing costs. Moreover, the protrusion amount of the protrusion 28 of the terminal 26 can be reduced, which allows the bonding portion of the terminal 26 to the conductive resin 20 to be miniaturized and increases the flexibility of the bonding position of the terminal 26 to the conductive resin 20.

[0032] Furthermore, the protruding portion 28 penetrates the skin layer 20C of the conductive resin 20 and penetrates into the inner portion 20D of the conductive resin 20. Therefore, the protruding portion 28 can be well conducted to the conductive material 20A, and the terminal 26 can be well conducted to the conductive resin 20.

[0033] Moreover, the conductive material 20A is fibrous, so that the protruding portion 28 of the terminal 26 can be properly electrically connected to the conductive material 20A, and the terminal 26 can be properly electrically connected to the conductive resin 20.

[0034] Second Embodiment FIG. 4A is a cross-sectional view showing an exploded state of a conductive structure 50 according to a second embodiment of the present invention, and FIG. 4B is a cross-sectional view showing a combined state of the conductive structure 50.

[0035] The conductive structure 50 according to this embodiment has almost the same configuration as that of the first embodiment, but differs in the following respects.

[0036] 4A and 4B , in the conductive structure 50 according to this embodiment, a plurality of protruding portions 28 with large protrusion amounts (hereinafter referred to as “high protruding portions 28A”) and a plurality of protruding portions with small protrusion amounts (hereinafter referred to as “low protruding portions 28B”) are formed on the rear surface (front surface) of the terminal 26, and the plurality of low protruding portions 28B are arranged around the entire circumference of the plurality of high protruding portions 28A. The protruding amount of the high protruding portions 28A is equal to or greater than the thickness of the skin layer 20C of the conductive resin 20, and the protruding amount of the low protruding portions 28B is less than the thickness of the skin layer 20C. The high protruding portions 28A penetrate the skin layer 20C of the conductive resin 20 and penetrate into the inner portion 20D of the conductive resin 20, thereby providing electrical conductivity between the high protruding portions 28A and the conductive material 20A of the inner portion 20D. The low protrusion portion 28B penetrates the skin layer 20C of the conductive resin 20, but does not penetrate the inner portion 20D of the conductive resin 20, so that the low protrusion portion 28B is not electrically connected to the conductive material 20A of the conductive resin 20 (skin layer 20C and inner portion 20D).

[0037] Here, this embodiment can also achieve the same functions and effects as the first embodiment.

[0038] Furthermore, the terminal 26 is provided with a high protrusion 28A and a low protrusion 28B, and the high protrusion 28A is electrically connected to the conductive material 20A of the inner portion 20D of the conductive resin 20, while the low protrusion 28B is not electrically connected to the conductive material 20A of the conductive resin 20. Therefore, even when the low protrusion 28B is provided, the high protrusion 28A allows the terminal 26 to be well connected to the conductive resin 20.

[0039] Furthermore, if the protrusion amount of the protrusion 28 penetrating the conductive resin 20 is large, the reduction in the strength of the conductive resin 20 due to the protrusion 28 is large, and the bonding strength of the protrusion 28 to the conductive resin 20 is small. On the other hand, if the protrusion amount of the protrusion 28 penetrating the conductive resin 20 is small, the reduction in the strength of the conductive resin 20 due to the protrusion 28 is small, and the bonding strength of the protrusion 28 to the conductive resin 20 is large. Therefore, even if the high protrusion 28A is provided, the low protrusion 28B allows the terminal 26 to be firmly bonded to the conductive resin 20.

[0040] Furthermore, the low protrusions 28B are arranged around the high protrusions 28A, so that the low protrusions 28B can effectively prevent the protrusions 28 from peeling off from the conductive resin 20, and the low protrusions 28B can effectively bond the terminals 26 to the conductive resin 20.

[0041] In the first and second embodiments, the conductive resin 20 of the garnish 16 serves as an electrode for detecting contact of an occupant with the garnish 16 .

[0042] However, the conductive resin 20 may be used as an electrocardiogram electrode for detecting the electrocardiogram waveform of the occupant. In this case, the decorative layer 16C is not provided on the front side of the conductive resin 20 (electrocardiogram electrode), and the skin layer 20C is removed. Then, a differential voltage between the left and right electrocardiogram electrodes that the occupant's left and right hands contact, respectively, is detected to detect the occupant's electrocardiogram waveform.

[0043] Furthermore, the conductive resin 20 may be additionally provided as a DRL electrode (Driven Right Leg electrode) on the steering wheel 12 (particularly the rim portion 12B). In this case, the decorative layer 16C is not provided on the front side of the conductive resin 20 (DRL electrode), and the skin layer 20C is removed. When the occupant's hand touches the DRL electrode, common-mode signal noise that has entered the pair of electrocardiogram electrodes via the occupant is inverted and amplified and fed back to the occupant via the DRL electrode, thereby reducing the common-mode signal noise that enters the pair of electrocardiogram electrodes via the occupant.

[0044] Furthermore, in the first and second embodiments, the conductive material 20A is fibrous. However, the conductive material 20A may be granular.

[0045] In the first and second embodiments, the conductive structures 10 and 50 are applied to the steering 12. However, the conductive structures 10 and 50 may be applied to something other than the steering 12.

[0046] The disclosure of Japanese Patent Application No. 2023-223460, filed on December 28, 2023, is incorporated herein by reference in its entirety.

[0047] DESCRIPTION OF SYMBOLS 10... Conductive structure, 20... Conductive resin, 20A... Conductive material, 20B... Resin, 26... Terminal, 28... Protrusion part, 28A... High protrusion part (protrusion part), 28B... Low protrusion part (protrusion part), 50... Conductive structure

Claims

1. A conduction structure is configured by molding a resin mixed with a conductive material and is used for detecting a human body. The conduction structure includes a conductive resin and a terminal provided with a protruding portion that protrudes and penetrates inward from the peripheral surface of the conductive resin to be electrically connected to the conductive material.

2. The conduction structure according to claim 1, wherein the conductive material is in a fibrous form.

3. The conduction structure according to claim 1 or claim 2, wherein the terminal is provided with a protruding portion having a large protrusion amount and a protruding portion having a small protrusion amount.

4. The conduction structure according to claim 3, wherein the protruding portion having a large protrusion amount is electrically connected to the conductive material, and the protruding portion having a small protrusion amount is not electrically connected to the conductive material.

5. The conduction structure according to claim 3 or claim 4, wherein the protruding portion having a small protrusion amount is arranged around the protruding portion having a large protrusion amount.

6. The conduction structure according to any one of claims 1 to 5, wherein the mixing density of the conductive material in the peripheral portion of the conductive resin is lower than the mixing density of the conductive material in the inner portion of the peripheral portion of the conductive resin.

7. The conduction structure according to any one of claims 1 to 6, wherein the protruding portion penetrates into the conductive resin in a molten state of the conductive resin.

8. The conduction structure according to any one of claims 1 to 7, wherein the terminal and the protruding portion are bonded to the conductive resin.

9. The conduction structure according to any one of claims 1 to 8, further comprising a dielectric portion provided on the peripheral surface of the conductive resin.

10. The conduction structure according to claim 9, wherein the conductive resin is used for detecting contact of a human body with the dielectric portion.

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