Electrode structure, steering wheel, and method for manufacturing steering wheel

1 . An electrode structure disposed on an outer circumference of a core metal of a steering wheel provided in a vehicle, the electrode structure comprising:

an insulator; and

a first electrode in a shape of a line, the first electrode being disposed on a first surface of the insulator, the first surface being on an opposite side of the insulator relative to a second surface of the insulator that faces the core metal of the steering wheel, wherein

the insulator includes a first engagement portion that engages with an engagement-target portion included in the core metal,

the first engagement portion extends from the second surface of the insulator,

the first engagement portion is inserted into the engagement-target portion,

the first engagement portion includes a fastener hole into which a fastener is inserted, and

the insulator engages with the engagement-target portion included in the core metal by inserting the fastener, which passes through the engagement-target portion, into the fastener hole of the first engagement portion.

2 . The electrode structure according to claim 1 , wherein

the first electrode is configured to be switchable between functioning as a sensor electrode that detects a driver's grip on the steering wheel and functioning as a heater wire that warms the steering wheel.

3 . The electrode structure according to claim 2 , wherein

the first electrode is selectively switched between use as the sensor electrode and use as the heater wire, such that the first electrode is exclusively used as either the sensor electrode or the heater wire at a given time.

4 . The electrode structure according to claim 1 , further comprising:

a second electrode disposed on the second surface of the insulator.

5 . The electrode structure according to claim 4 , wherein

in a cross section of the steering wheel taken in a plane perpendicular to a circumferential direction of the steering wheel:

the first electrode is disposed along a shape of the first surface of the insulator; and

the second electrode is disposed along a shape of the second surface of the insulator.

6 . The electrode structure according to claim 4 , wherein

when the first electrode is used as a sensor electrode, an AC voltage is applied to the first electrode, the AC voltage having a same phase as an AC voltage applied to the second electrode.

7 . The electrode structure according to claim 1 , wherein

the first electrode is a heater wire that warms the steering wheel.

8 . The electrode structure according to claim 1 , wherein

the first electrode is a sensor electrode that detects a driver's grip on the steering wheel.

9 . The electrode structure according to claim 1 , wherein

the insulator includes a first insulator and a second insulator,

the first insulator includes the first surface and a third surface, the third surface being on an opposite side of the first insulator relative to the first surface,

the first electrode is disposed on the first surface of the first insulator,

the second insulator includes the second surface,

the first engagement portion extends from the second surface of the second insulator,

the electrode structure further comprises a second electrode is disposed on the third surface of the first insulator, and

the second insulator is disposed between the second electrode and the core metal.

10 . The electrode structure according to claim 9 , wherein

in a cross section of the steering wheel taken in a plane perpendicular to a circumferential direction of the steering wheel, the first insulator, the second insulator, the first electrode, and the second electrode are disposed at least in a range from an outer circumferential side of the steering wheel to an inner circumferential side of the steering wheel.

11 . The electrode structure according to claim 9 , wherein

the first insulator comprises a resin material,

the second insulator comprises a resin material,

the first electrode includes metal plating or a metal thin film, and

the second electrode includes metal plating, a metal thin film, a metal sheet, or a metal plate.

12 . The electrode structure according to claim 9 , wherein

the first insulator comprises a resin material,

the second insulator comprises a resin material,

the first electrode includes a resin sheet and a conducting wire,

the conducting wire is disposed on and sewed to a surface of the resin sheet with a sewing thread, the surface being on an opposite side of the resin sheet relative to a surface of the resin sheet that faces the first surface of the first insulator, and

the second electrode includes metal plating, a metal thin film, a metal sheet, or a metal plate.

13 . The electrode structure according to claim 9 , wherein

the first insulator includes a first positioning portion, and

the second insulator includes a second positioning portion that interlocks with the first positioning portion.

14 . A steering wheel comprising:

the electrode structure according to claim 1 ;

the core metal; and

a foam that covers the core metal.

15 . A method for manufacturing a steering wheel, the method comprising:

engaging the first engagement portion included in the electrode structure of the steering wheel according to claim 14 with the engagement-target portion included in the core metal; and

covering the core metal using the foam while the first engagement portion is engaged with the engagement-target portion.

16 . The electrode structure according to claim 1 , wherein

the insulator further includes a second engagement portion including an engagement claw.

17 . The electrode structure according to claim 16 , wherein

the first engagement portion including the fastener hole and the second engagement portion including the engagement claw are provided at different positions in a circumferential direction of the core metal of the steering wheel.

18 . The electrode structure according to claim 17 , wherein

the first engagement portion is a cylindrical or round tubular portion that extends from the second surface of the insulator.

19 . The electrode structure according to claim 17 , wherein

the second engagement portion is a rod-shaped or plate-shaped portion that extends from the second surface of the insulator.

20 . An electrode structure disposed on an outer circumference of a core metal of a steering wheel provided in a vehicle, the electrode structure comprising:

a first insulator;

a resin sheet disposed on a first surface of the first insulator, the first surface being on an opposite side of the first insulator relative to a second surface of the first insulator that faces the core metal of the steering wheel;

a first electrode in a shape of a line, the first electrode being disposed on one surface of the resin sheet; and

a second electrode disposed on an other surface of the resin sheet, the other surface being a rear surface of the one surface of the resin sheet and being a surface of the resin sheet that faces the first surface of the first insulator, wherein

the first insulator includes an engagement portion that engages with an engagement-target portion included in the core metal,

the first electrode is configured to be switchable between functioning as a sensor electrode that detects a driver's grip on the steering wheel and functioning as a heater wire that warms the steering wheel,

the engagement portion extends from the second surface of the first insulator,

the engagement portion is inserted into the engagement-target portion,

the engagement portion includes a fastener hole into which a fastener is inserted, and

the first insulator engages with the engagement-target portion included in the core metal by inserting the fastener, which passes through the engagement-target portion, into the fastener hole of the engagement portion.