JP2574693Y2 - Membrane switch - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane switch, and more particularly to a membrane switch suitable for a steering wheel of a vehicle having an airbag device.

[0002]

2. Description of the Related Art An airbag device reduces the collision of an occupant in front of a passenger compartment by inflating and deploying an airbag stored in a steering wheel when a vehicle collides. By the way, in recent years, a vehicle equipped with such an airbag device has been proposed in which various input switches such as a car phone and an audio are provided on a center pad of a steering wheel.

Heretofore, a general switch device of this type is one in which a plurality of push switches are housed together with an airbag inside a steering wheel, and key top groups corresponding to the push switches are arranged on a center pad. When an occupant selects and pushes each keytop, a push switch corresponding to the keytop is operated to switch on / off.

[0004]

However, in the above-mentioned prior art, when the airbag is inflated and deployed, the push switch group and the key top group arranged in front of the airbag inflating toward the occupant include the group. Because of the scattering, there was a problem in terms of safety.

The present invention has been made in view of such circumstances of the prior art, and has as its object to provide a membrane switch which maintains mechanical strength at all times and can be easily broken only when necessary. It is in.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a vehicle steering system having an airbag device.
A membrane switch used for a steering wheel, in which a pair of base films on which electrodes are patterned is laminated via spacers such that the electrodes face each other, the base film reinforces its mechanical strength.
A plurality of metal reinforcement layers for
It is characterized in that the formation of the strip-shaped cutting line between the reinforcing layer.

[0007]

When a base film having a low breaking strength, for example, an ultra-thin film is used, a plurality of metal supplements for reinforcing the mechanical strength are provided on the base film.
Since a strong layer is formed , the membrane is
The mechanical strength of the lens switch is secured. On the other hand, when the stress from the air bag during inflation and deployment of the airbags is applied to the base film, the base film is easily broken along the cutting line in the absence of the reinforcing layer, the air bag through the base film is broken Deployed outside.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a steering wheel to which a membrane switch according to an embodiment of the present invention is applied, FIG. 2 is a cross-sectional view of the membrane switch of FIG. 1, and FIG. 3 is a view of a lower base film provided in the membrane switch of FIG. It is a top view.

In FIG. 1, reference numeral 1 denotes a steering wheel, and a center portion 3 is provided at the center of the steering wheel 1 via a spoke 2. The center portion 3 has a concave shape with an open upper end, and accommodates therein a membrane switch, a folded airbag, and a detonator thereof, which will be described later. The center 3
A center pad 4 is adhered to the open end of the device, and a membrane switch is exposed from a plurality of openings 5 formed in the center pad 4.

As shown in FIG. 2, the membrane switch includes a lower base film 7 having a lower electrode 6, a spacer film 9 having a through hole 8, an upper base film 11 having an upper electrode 10, a swelling portion. The display film 13 includes a display film 13, and these films are laminated in order from the bottom and integrated with an adhesive tape (not shown) or the like. The lower electrode 6 and the upper electrode 10 face each other with a predetermined gap in the through hole 8. The bulging portion 12 is located above these electrodes 6 and 10 and is exposed from the opening 5 of the center pad 4. doing. Therefore, when the operator (occupant) pushes the bulging portion 12, the pressing force causes the upper base film 11 to bend downward and the electrodes 6 and 10 to come into contact, and the switch is switched from off to on. When the pressing force on the bulging portion 12 is removed, the upper base film 11 and the display film 13 return to the state shown in FIG.
Since the two electrodes 6 and 10 are separated from each other, the switch is switched from on to off.

The lower base film 7 is, for example, 75
μm ultra-thin PET (polyethylene terephthalate)
The film is made of a material which is easily broken by itself. As shown in FIG. 3, on the upper surface of the lower base film 7, the lower electrode 6 and its routing pattern 6a are provided in an arbitrary shape, and a dummy pattern 14 which is not involved in the switching of the switch is provided in almost the entire remaining area. Is provided. Both the routing pattern 6a and the dummy pattern 14 are made of metal foil, for example, copper foil.
Although it is patterned by a known etching technique, a strip-shaped cutting line 15 (shown by a broken line in FIG. 3) in which the dummy pattern 14 does not exist is formed at an arbitrary position of the lower base film 7. Accordingly, although the mechanical strength of the cutting line 15 traversed only by the wiring pattern 6a is inferior to the lower base film 7, the mechanical strength of almost all other areas is reduced by the wiring pattern 6a (the lower electrode 6).
And the dummy pattern 14.

Although not shown, the upper base film 1
1 has the same structure as the lower base film 7, that is, the lower surface of the upper base film 11 is provided with a dummy pattern over substantially the entire area except for a strip-shaped cutting line. Each of the films 13 is formed of a material having a low breaking strength.
The cutting lines 15 of the base films 7, 11 are arranged so as to overlap each other when viewed in plan.

In the above embodiment, when the occupant presses the bulging portion 12 exposed from the opening 5 of the center pad 4 with a finger or the like, the pressing force brings the two electrodes 6 and 10 into contact with each other.
The switch switches from off to on. When the pressing force is removed, the electrodes 6 and 10 are separated from each other, and the switch is switched from on to off. Under such normal use conditions,
Since the mechanical strength of the lower base film 7 and the upper base film 11 is increased by the dummy pattern 14, breakage of the base films 7, 11 and the routing pattern is prevented.

On the other hand, when an airbag (not shown) stored in the steering wheel 1 is inflated and deployed at the time of a vehicle collision, the films 7, 9, 11, and 13 of the membrane switch are connected to both bases by the inflation force of the airbag. Since the airbag is easily broken along the cutting line 15 of the films 7, 11, the airbag passes through the broken portion and pushes away the center pad 4 to be smoothly inflated and deployed in the direction of the occupant. In this case, since the membrane switch is formed by laminating a plurality of films, there is no possibility that the occupant may be injured by the broken membrane switch.

In the above-described embodiment, the case where an ultra-thin PET film is used as the base films 7 and 11 has been described.
For example, a polyethylene film having a normal thickness can be used. For the spacer film 9 and the display film 13, a material having a normal breaking strength is used.
A cut such as a half cut may be formed in a portion corresponding to the cutting line 15 of both base films 7 and 11.

[0016]

[Effects of the Invention] As described above, according to the present invention,
It is possible to provide a membrane switch which maintains mechanical strength at all times and can be easily cut only when necessary, and
Even if it is attached to a steering wheel of a vehicle equipped with an airbag device, safety can be ensured without hindering inflation and deployment of the airbag.

[Brief description of the drawings]

FIG. 1 is a front view of a steering wheel to which a membrane switch according to the present invention is applied.

FIG. 2 is a cross-sectional view of the membrane switch of FIG.

FIG. 3 is a plan view of a lower base film provided in the membrane switch of FIG. 2;

[Explanation of symbols]

Reference Signs List 1 steering wheel 4 center pad 5 opening 6 lower electrode 7 lower base film 8 through hole 9 spacer film 10 upper electrode 11 upper base film 12 bulging portion 13 display film 14 dummy pattern (reinforcing layer) 15 cutting line

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) H01H 13/70 B60R 21/16 H05K 1/02 H01H 13/52 B60R 21/20

Claims (1)

(57) [Scope of request for utility model registration] 1. A vehicle steer provided with an airbag device.
A membrane switch used for a steering wheel, in which a pair of base films on which electrodes are patterned is laminated via spacers such that the electrodes face each other, the base film reinforces its mechanical strength.
A plurality of metal reinforcement layers for
Membrane switch, characterized in that the formation of the strip-shaped cutting line between the reinforcing layer.