JP2013021049A - Electromagnetic wave shield gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shield property without increasing the width of a gasket and a compressive reaction force in the gasket made of a composite material of metal and rubber.SOLUTION: A gasket 1 is disposed between a pair of conductive members 2, 3 and includes a structure where elastic films 12, 13, which are respectively formed by rubber elastic materials and closely contact with facing surfaces 2b, 3b of the conductive members 2, 3, are deposited on both surfaces of a substrate 11 made of a conductive metal in the thickness direction. The gasket 1 has: an outer shield edge 1f where an outer edge part 11b of the substrate 11 is bent to the one conductive member 2 side and extends along an outer side surface 2a of the one conductive member 2; and an inner shield edge 1e where an inner edge part 11a of the substrate 11 is bent to the other conductive member side 3 and extends along the inner side surface 3a of the other conductive member 3.

Description

  The present invention relates to an electromagnetic wave shielding gasket, and more particularly, in a gasket that is interposed in a gap between conductive members to prevent fluid leakage and foreign matter from entering, the function of shielding electromagnetic wave noise that attempts to pass through the gap is provided. About things.

  Conventionally, for example, as shown in FIG. 3, a cylinder head and a cylinder block of an internal combustion engine, or a cylinder block and an oil pan, etc. are used to maintain airtightness between the first member 110 and the second member 120 that are coupled to each other. The gasket 100 interposed between the two is coated with elastic films 102 and 103 made of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) on both sides of an elastically deformable metal substrate 101.・ Uses made of rubber composite material.

  This type of gasket 100 has a plurality of continuous seal beads 100a to 100d that are alternately formed on both sides in the thickness direction by plastic working, and the seal beads 100a to 100d are elastic films 102 and 103, and are first films. By being in close contact with the member 110 and the second member 120, a sealing function is exhibited (for example, see Patent Documents 1 and 2 below).

  By the way, in recent years, with the spread of hybrid vehicles and electric vehicles, many electronic devices and electric devices are mounted on the vehicles, but the radiation intensity of electromagnetic noise EMI (electro-magnetic interference) generated from these electronic devices. Is large, there is a risk of adverse effects such as the destruction or malfunction of the electronic circuits of the surrounding equipment. For gaskets used for casings of electronic equipment, in addition to sealing properties against dust, water, etc., good Electromagnetic shielding properties are required.

  However, in the gasket 100 as shown in FIG. 3, for example, the first member 110 is a casing that houses an electronic device, and the second member 120 is a lid that is coupled so as to close the opening of the first member 110. In this case, even if the first member 110, the second member 120, and the substrate 101 of the gasket 100 are made of a conductive metal, the seal beads 100 a to 100 d are in relation to the first member 110 and the second member 120. Electrically insulating elastic films 102 and 103 are in close contact, that is, the seal beads 100a to 100d are generated from an electronic device housed in the internal space S between the first member 110, the second member 120, and the substrate 101. Electromagnetic gaps due to the elastic films 102 and 103 that allow the transmission of electromagnetic wave noise EMI are present, and therefore the electromagnetic wave shielding property is poor. It was.

  Further, in a gasket made of this type of metal rubber composite material, as in Patent Document 3 below, an elastic film is formed only on a seal portion against dust, water, etc., and a substrate made of a conductive metal in other portions, Although there are those that have secured electromagnetic wave shielding properties by making metal contact with a mating member made of conductive metal and making it electrically conductive, both a seal part due to contact with the elastic film and an electromagnetic wave shield part due to metal contact with the substrate are formed Therefore, it is inevitable that the width of the gasket becomes wide, and there is also a problem that the compression reaction force in the thickness direction due to the fastening force of a screw or the like becomes large.

JP 2008-223952 A JP 2005-290359 A JP-A-11-274783

  The present invention has been made in view of the above points, and its technical problem is that a gasket made of a metal-rubber composite material does not increase the width of the gasket or increase the compression reaction force. It is to provide electromagnetic shielding properties.

  As a means for effectively solving the technical problem described above, an electromagnetic wave shielding gasket according to the present invention is a gasket interposed between a pair of conductive members, and both sides in the thickness direction of a substrate made of a conductive metal. Each of which is made of a rubber-like elastic material and has a structure in which an elastic film capable of being in close contact with the opposing surface of the conductive member is attached, and the outer edge portion of the substrate is bent toward one of the conductive members. An outer shielding edge extending along the outer surface of the conductive member, and an inner shielding edge in which the inner edge portion of the substrate is bent toward the other conductive member side and extends along the inner surface of the other conductive member It is.

  In the above configuration, the elastic film made of a rubber-like elastic material exhibits sealing properties against dust, water, and the like by being in close contact with the opposing surface of the conductive member, and the substrate is elastically deformed by the reaction force. In addition to providing the intimate force of the elastic film to the conductive member, it is made of a conductive metal and shields the transmission of electromagnetic noise. In addition, the outer shielding edge and the inner shielding edge are formed by a part of the substrate extending so as to cover an electromagnetic gap formed by an electrically insulating elastic film interposed between the conductive member and the substrate from the outside and the inside. The electromagnetic wave noise which tries to permeate | transmit a static gap or the electromagnetic wave noise which permeate | transmitted the said electromagnetic gap is shielded.

  According to the electromagnetic shielding gasket according to the present invention, the outer edge and the inner edge of the substrate that shields transmission of electromagnetic noise are bent to the opposite sides to form the outer shielding edge and the inner shielding edge. Sealing properties and electromagnetic wave shielding properties can be achieved without increasing the compression reaction force.

It is sectional drawing of the mounting state which shows preferable embodiment of the electromagnetic wave shielding gasket which concerns on this invention. It is sectional drawing of the mounting state which shows other preferable embodiment of the electromagnetic wave shielding gasket which concerns on this invention. It is sectional drawing of the mounting state which shows an example of the conventional gasket.

  Hereinafter, a preferred embodiment of the electromagnetic shielding gasket according to the present invention will be described with reference to FIG.

  The gasket 1 according to the present embodiment is made of a first conductive member 2 such as a casing made of a conductive metal or the like in which an electronic device (not shown) is housed in the internal space S, and a conductive metal or the like. It is arranged between the second conductive member 3 such as a lid which is arranged so as to close the opening of the first conductive member 2 and is connected by a screw or the like (not shown). The first conductive member 2 corresponds to one of the conductive members described in claim 1, and the second conductive member 3 corresponds to the other conductive member described in claim 1. Is.

  The gasket 1 has a structure in which elastic films 12 and 13 made of rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) are coated on both surfaces of a substrate 11 made of an electrically deformable conductive metal. In other words, it is made of a metal rubber composite material, and has a plurality of continuous seal beads 1a to 1d that are alternately protruded to both sides in the thickness direction by plastic working (press molding). Among these, the innermost seal bead 1a and the third seal bead 1c from the inner side are bent toward the first conductive member 2, and the second seal bead 1b from the innermost side is the outermost (fourth from the inner side). The seal bead 1d is formed in a bent shape that is convex toward the second conductive member 3 side.

  Further, the inner edge portion 11a of the substrate 11 is bent toward the second conductive member 3 side and extends along the inner side surface 3a of the second conductive member 3, thereby forming an inner shielding edge 1e. The outer edge portion 11b is bent toward the first conductive member 2 side and extends along the outer surface 2a of the first conductive member 2, thereby forming an outer shielding edge 1f. That is, the inner width w between the inner shielding edge 1e and the outer shielding edge 1f is equal to or slightly larger than the thickness t of the first conductive member 2 and the second conductive member 3, The heights of the inner shielding edge 1e and the outer shielding edge 1f are higher than the gap G between the first conductive member 2 and the second conductive member 3.

  In this embodiment, the elastic films 12 and 13 are attached to the entire area of both surfaces of the substrate 11 including the inner shielding edge 1e and the outer shielding edge 1f.

  The gasket 1 of the embodiment of the present invention configured as described above is interposed between the opposing surfaces 2b and 3b of the first conductive member 2 and the second conductive member 3, and the first conductive member By joining the member 2 and the second conductive member 3 through a screw (not shown), the opposing surfaces 2b and 3b are compressed, that is, the seal beads 1a to 1d are appropriately deformed, Due to the reaction force, the innermost seal bead 1a and the third seal bead 1c are in close contact with the opposing surface 2b of the first conductive member 2 in one elastic film 12 covering this, and the second seal bead 1b from the inner side. The outermost seal bead 1d is in close contact with the facing surface 3b of the second conductive member 3 in the other elastic film 13 covering it, so that dust, water, etc. from the outside (right side in FIG. 1) Equipment is stored It was those to achieve the high sealing properties to prevent the intrusion into the internal space S.

  The substrate 11 made of a conductive metal is elastically deformed in the compression direction between the opposing surfaces 2b and 3b of the first conductive member 2 and the second conductive member 3, so that the reaction force causes the elastic films 12 and 13 to move. In addition to providing a close force to the first conductive member 2 and the second conductive member 3, the transmission of electromagnetic wave noise EMI generated in an electronic device existing in the internal space S is shielded.

  The inner shielding edge 1e is an inner edge portion of the substrate 11 extending like a wall covering the electromagnetic gap due to the elastic film 13 interposed between the second conductive member 3 and the substrate 11 in the seal beads 1b and 1d. By 11a, electromagnetic noise EMI generated in the electronic device existing in the internal space S and trying to pass through the electromagnetic gap by the elastic film 13 is shielded inside the seal bead 1b and adversely affects the surrounding electronic circuits and the like. It suppresses.

  Further, part of the electromagnetic wave noise EMI generated in the electronic device existing in the internal space S is transmitted through the electromagnetic gap formed by the elastic film 12 interposed between the first conductive member 2 and the substrate 11 in the seal beads 1a and 1c. However, the outer shielding edge 1f shields the transmitted electromagnetic wave noise ΔEMI by the outer edge portion 11b of the substrate 11 extending like a wall covering the electromagnetic gap due to the elastic film 12 from the outside, and surrounding electronic circuits, etc. It suppresses adverse effects on

  In addition, according to the embodiment shown in FIG. 1, the outer shielding edge 1 f is bent toward the lower side (the first conductive member 2 side which is the casing). Even if there is a gap between the outer surface 2a of the first conductive member 2, dust, water, etc. from the outside (right side in FIG. 1) will not accumulate inside the outer shielding edge 1f.

  In addition, the cross-sectional shape of the seal beads 1a to 1d can be variously changed in addition to the shape shown in FIG. 1, and the present invention can also be applied to those in which the seal beads 1a to 1d are not formed.

  Further, according to the embodiment shown in FIG. 1, both sides of the inner shielding edge 1e and the outer shielding edge 1f are covered with the elastic films 12 and 13, but like the other embodiments shown in FIG. At the inner shielding edge 1e and the outer shielding edge 1f, the inner edge portion 11a and the outer edge portion 11b of the conductive substrate 11 are exposed from the elastic films 12 and 13, and are formed into a leaf spring shape to form the inner side surface 3a of the second conductive member 3 and If the substrate 11 is electrically connected to the first conductive member 2 and the second conductive member 3 by adopting a configuration in which the outer surface 2a of the first conductive member 2 can be elastically brought into metal contact, an electromagnetic wave can be obtained. Noise EMI, ΔEMI can be prevented from diffracting the inner edge portion 11a and the outer edge portion 11b (the inner shielding edge 1e and the outer shielding edge 1f) of the substrate 11, and the electromagnetic wave shielding function can be further enhanced.

DESCRIPTION OF SYMBOLS 1 Gasket 11 Board | substrate 11a Inner edge part 11b Outer edge part 12, 13 Elastic film 1a-1d Seal bead 1e Inner shielding edge 1f Outer shielding edge 2 1st electroconductive member (one electroconductive member)
2a Outer side surface 3 Second conductive member (the other conductive member)
3a inner surface

Claims (1)

  A gasket interposed between a pair of conductive members, and an elastic film made of a rubber-like elastic material, which can be in close contact with the opposing surface of the conductive member, on both sides in the thickness direction of the substrate made of a conductive metal. The outer edge of the substrate is bent toward one conductive member and extends along the outer surface of the one conductive member, and the inner edge of the substrate is the other conductive member. An electromagnetic wave shielding gasket having an inner shielding edge that is bent toward the conductive member side and extends along the inner side surface of the other conductive member.

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