Electromagnetic shielding gasket and method for manufacturing the same

Abstract

The object is to provide an electromagnetic shielding gasket 3 and a manufacturing method for the electromagnetic shielding gasket 3 that can suppress variations in the contact state with the housing body 21 and the lid 22 and ensure stable shielding performance. [Solution] An electromagnetic shielding gasket 3 is interposed between the mating surface of a housing body 21 and a lid body 22 that constitute a conductive housing 2, and is provided with a first contact portion 31 that contacts the mating surface 21a of the housing body 21, and a second contact portion 32 that overlaps the first contact portion 31 and contacts the mating surface 22a of the lid body 22, and is characterized in that the direction along the width of the mating surface 21a is defined as the width direction X, and the first contact portion 31 and the second contact portion 32 are formed by bending back, at the specified width D, a thin expanded metal with a plate thickness T that is wider than a desired specified width D in the width direction X, and are formed into a continuous wave shape in the longitudinal direction Y that is perpendicular to the width direction X in a planar view.

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic shielding gasket that prevents, for example, electromagnetic waves generated inside an electronic device from leaking to the outside, or electromagnetic waves generated in another electronic device from entering the inside of an electronic device, and a method for manufacturing an electromagnetic shielding gasket. [Background technology]

[0002] For example, electric vehicles, hybrid vehicles, and other electrically powered vehicles are equipped with numerous electronic devices. When such electronic devices are energized, they emit electromagnetic waves from the electronic circuits and electronic components housed inside. If the electromagnetic waves leak from the electronic devices as leakage electromagnetic waves, they may act as noise on surrounding electronic devices.

[0003] Therefore, in electronic devices, the housing is made of a conductive material, and an electromagnetic shielding gasket is interposed between the first and second members that make up the housing, thereby preventing electromagnetic waves from leaking from the gap between the first and second members and preventing leaked electromagnetic waves from entering through the gap between the first and second members, thereby ensuring shielding performance. As such an electromagnetic shielding gasket, for example, as disclosed in Patent Document 1, an electromagnetic shielding gasket made of conductive expanded metal is known.

[0004] However, in Patent Document 1, the electromagnetic shielding gasket is made of a thin, flat expanded metal plate, so when the electromagnetic shielding gasket is pressed between the first member and the second member, the electromagnetic shielding gasket is prone to plastic deformation.

[0005] In this case, the electromagnetic shielding gasket of Patent Document 1 has a problem in that it is not possible to ensure stable shielding performance because there is a risk that variations in the state of contact with both the first member and the second member may occur due to plastic deformation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Microfilm of Utility Model Application No. 63-088621 (Utility Model Application No. 02-9500) Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above-mentioned problems, the present invention aims to provide an electromagnetic shielding gasket and a method for manufacturing an electromagnetic shielding gasket that can reduce variations in the contact state with the first member and the second member and ensure stable shielding performance. [Means for solving the problem]

[0008] The present invention provides an electromagnetic shielding gasket that is interposed between the mating surfaces of a first member and a second member that constitute a conductive housing, and that includes a first contact portion that contacts one of the mating surfaces and a second contact portion that overlaps the first contact portion and contacts the other mating surface, with the direction along the width of the mating surfaces being the width direction, and the first contact portion and the second contact portion are formed by bending back a thin expanded metal plate that is wider than a desired predetermined width in the width direction at the predetermined width, and are formed into a continuous wave shape in the longitudinal direction that is perpendicular to the width direction in a planar view.

[0009] The present invention also provides a method for manufacturing an electromagnetic shielding gasket to be interposed between a mating surface between a first member and a second member that constitute a conductive housing, the method comprising the steps of: a bending step in which a thin expanded metal plate having a length in the width direction that is wider than a desired predetermined width is bent back at the predetermined width along the width of the mating surface to form a first contact portion that contacts one of the mating surfaces and a second contact portion that overlaps the first contact portion and contacts the other mating surface; and a corrugating step in which the overlapped first contact portion and second contact portion are corrugated together to form a continuous wave shape in the longitudinal direction that is perpendicular to the width direction in a plan view.

[0010] Overlapping the first contact portion means directly overlapping the first contact portion, or indirectly overlapping the first contact portion via a non-contact portion that does not contact either the first member or the second member. The expanded metal is a component in which a plurality of meshes are arranged in a staggered pattern and are formed by expanding a thin conductive plate while making cuts in it, or a component in which a plurality of meshes are arranged in a staggered pattern and are formed by expanding a thin conductive plate while making cuts in it.

[0011] The expanded metal may be expanded metal that has undergone surface treatment such as rust prevention treatment to improve rust prevention performance or plating treatment to improve conductivity, or may be expanded metal that has not undergone surface treatment. The above-mentioned wavy shape continuing in the longitudinal direction refers to a shape in which the ridge line extending from one side to the other in the width direction is approximately perpendicular to the longitudinal direction in a planar view, or a shape in which the ridge line extending from one side to the other in the width direction intersects the longitudinal direction in a planar view.

[0012] According to this invention, expanded metal that is wider than a predetermined width is bent back to the predetermined width and overlapped, and then formed into a continuous wave shape in the longitudinal direction. This allows the electromagnetic shielding gasket to have higher elasticity in the height direction of the wave shape than an electromagnetic shielding gasket composed only of a first contact portion formed in a wave shape.

[0013] Therefore, when the electromagnetic shielding gasket is pressed between the first and second members, plastic deformation due to the pressing load is suppressed, and the electromagnetic shielding gasket can maintain contact with both the first and second members through its elasticity.

[0014] This allows the electromagnetic shielding gasket to stably secure contact points with the first and second members, and therefore the electromagnetic shielding gasket and the method for manufacturing the electromagnetic shielding gasket can reduce variations in the state of contact with the first and second members and ensure stable shielding performance.

[0015] In addition, since plastic deformation of the electromagnetic shielding gasket due to a pressing load can be suppressed, the electromagnetic shielding gasket and the method for manufacturing the electromagnetic shielding gasket can enable the electromagnetic shielding gasket to be reused.

[0016] As an aspect of the present invention, the second contact portion Is, When the first contact portion is unfolded into a plate-like shape, the first contact portion is provided on both sides in the width direction. Each of the second contact portions is formed such that the length in the width direction is equal to or less than half of the predetermined width. That's fine.

[0017] According to this configuration, the second contact portion in the unfolded state is bent back to overlap the first contact portion, so that bent-back portions can be formed at both ends in the width direction. This makes it less likely for the electromagnetic shielding gasket to get caught on another electromagnetic shielding gasket or the clothing of a worker than when both ends in the width direction are end faces, thereby improving the ease of assembly when assembling the electromagnetic shielding gasket into a housing.

[0018] In another aspect of the present invention, the expanded metal may be formed so that the shorter direction and the longer direction thereof substantially coincide with each other. With this configuration, the expanded metal has a continuous wave-like shape along the short side, so that the cross-sectional shapes of the first contact portion and the second contact portion in a longitudinal section along the longitudinal direction can be configured with a stepped cross-sectional shape of the expanded metal.

[0019] Therefore, the electromagnetic shield gasket can have a plurality of contact points that come into contact with the first member and a plurality of contact points that come into contact with the second member due to the elasticity of the corrugated shape near the peaks and valleys of the corrugated shape. This allows the electromagnetic shielding gasket to have a more stable contact state with the first member and the second member, thereby improving the shielding performance.

[0020] In another aspect of the present invention, the expanded metal may be formed so that its long grain direction and the longitudinal direction substantially coincide with each other. With this configuration, deformation of the mesh due to a tensile load in the longitudinal direction can be suppressed compared to when the short mesh direction and the longitudinal direction are substantially aligned.

[0021] Therefore, when the electromagnetic shielding gasket is formed into, for example, a continuous wave shape in the longitudinal direction, the mesh of the expanded metal is deformed, causing it to stretch in the longitudinal direction, preventing it from becoming narrower than the desired specified width.

[0022] Alternatively, when the electromagnetic shielding gasket is formed into a wave shape that continues in the longitudinal direction, for example, it is possible to prevent the bonds of the expanded metal from breaking due to deformation of the mesh. This allows the electromagnetic shielding gasket to ensure stable conductivity even when the thin expanded metal is formed into a corrugated shape, thereby improving shielding performance.

[0023] In another aspect of the present invention, the expanded metal along the longitudinal direction short Grain direction Or in the long direction The center-to-center distance may be less than 1 / 2 pitch of the wave shape. With this configuration, the mesh size is smaller than half the pitch of the corrugated shape, preventing the peaks and valleys of the corrugated shape from becoming meshes of the expanded metal. This ensures that the electromagnetic shielding gasket makes reliable contact with the first and second members, ensuring more stable shielding performance.

[0024] As another aspect of the present invention, a manufacturing method of an electromagnetic shielding gasket includes a punching step of punching a thin sheet of the expanded metal with a predetermined die to form a shape in which a plurality of strip-shaped portions wider than the predetermined width and extending in the longitudinal direction are juxtaposed at predetermined intervals in the width direction and both ends of the longitudinal direction of the plurality of strip-shaped portions are connected by widthwise edge portions extending in the width direction; a bending step of bending back the strip-shaped portions at the predetermined width to form the first contact portion and the second contact portion; a corrugating step of corrugating the expanded metal having the plurality of strip-shaped portions bent back at the predetermined width to form the corrugated shape that is continuous in the longitudinal direction; And A cutting step may be performed in which the strip-shaped portion formed into the wave shape is cut from the edge portion in the width direction.

[0025] According to this configuration, multiple strip-shaped portions bent back at a predetermined width are corrugated while connected at their widthwise edges, thereby reducing twisting of the strip-shaped portions due to corrugation compared to, for example, when strip-shaped portions bent back at a predetermined width and cut from their widthwise edges are corrugated.

[0026] As a result, the manufacturing method of the electromagnetic shielding gasket can prevent deterioration in the workability of assembling the electromagnetic shielding gasket to the housing due to twisting, and can suppress deterioration in the shielding performance of the electromagnetic shielding gasket due to twisting.

[0027] In addition, the manufacturing method of the electromagnetic shielding gasket allows multiple electromagnetic shielding gaskets to be obtained at once from a single piece of expanded metal, making it possible to efficiently produce multiple electromagnetic shielding gaskets with reduced twisting. [Effects of the Invention]

[0028] The present invention can provide an electromagnetic shielding gasket and a method for manufacturing an electromagnetic shielding gasket that can reduce variations in the contact state with the first member and the second member and ensure stable shielding performance. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 2 is an exploded perspective view showing the appearance of the electronic device in a disassembled state. [Figure 2] FIG. 2 is an external perspective view showing the appearance of the electromagnetic shielding gasket. [Figure 3] FIG. 1 is an explanatory diagram illustrating an expanded metal. [Figure 4] FIG. 2 is an explanatory diagram illustrating the configuration of an electromagnetic shielding gasket. [Figure 5] FIG. 2 is a cross-sectional view showing a cross section of the electromagnetic shielding gasket in a longitudinal cross section along the longitudinal direction. [Figure 6] FIG. [Figure 7] FIG. 10 is an explanatory diagram illustrating the first stage of the bending-back process. [Figure 8] FIG. 10 is an explanatory diagram illustrating a second stage of the bending-back process. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. 10 is an external perspective view showing the external appearance of an electromagnetic shield gasket according to a second embodiment. [Figure 12] FIG. 10 is an explanatory diagram illustrating a cross-sectional shape of an electromagnetic shielding gasket according to another embodiment. [Figure 13] FIG. 10 is an explanatory diagram illustrating an electromagnetic shield gasket according to another embodiment. [Figure 14] FIG. 10 is an explanatory diagram illustrating an electromagnetic shield gasket according to another embodiment. [Figure 15] FIG. 10 is an explanatory diagram illustrating an electromagnetic shield gasket according to another embodiment. [Figure 16] FIG. 10 is an explanatory diagram illustrating an electromagnetic shield gasket according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0030] An embodiment of the present invention will be described below with reference to the drawings. [Example]

[0031] In the first embodiment, an electromagnetic shield gasket 3 that blocks gaps in a housing 2 of an electronic device 1 to block the leakage of electromagnetic waves and the intrusion of leakage electromagnetic waves will be described with reference to FIGS. 1 to 5. FIG.

[0032] 1 shows an exploded perspective view of the electronic device 1, FIG. 2 shows an external perspective view of the electromagnetic shielding gasket 3, and FIG. 3 is an explanatory diagram illustrating the expanded metal, where FIG. 3(a) shows a front view of the expanded metal and FIG. 3(b) shows a cross-sectional view taken along the line AA in FIG. 3(a).

[0033] 4 is an explanatory diagram illustrating the configuration of the electromagnetic shield gasket 3, and FIG. 5 is a cross-sectional view of the electromagnetic shield gasket 3 taken along the longitudinal direction Y. As shown in FIG. 2 indicates the width direction of the electromagnetic shielding gasket 3 (hereinafter referred to as the width direction X), and the arrow Y in FIG. 2 indicates the longitudinal direction (hereinafter referred to as the longitudinal direction Y) that is approximately perpendicular to the width direction X in a plan view.

[0034] First, electronic device 1 is an electronic device mounted on a vehicle such as an automobile. As shown in Fig. 1, electronic device 1 includes a conductive housing 2, a circuit board (not shown) housed inside housing 2, and four electromagnetic shielding gaskets 3 that block leakage of electromagnetic waves from inside housing 2 to the outside and block intrusion of leaked electromagnetic waves into housing 2.

[0035] As shown in FIG. 1, the housing 2 comprises a box-shaped housing main body 21 that is open at the top, a substantially flat lid body 22 that covers the opening of the housing main body 21 with an electromagnetic shielding gasket 3 sandwiched therebetween, and a fastening member 23 for fixing the lid body 22 to the housing main body 21.

[0036] Specifically, the housing body 21 is formed in the shape of a roughly rectangular box in plan view, with an open top, and is made up of a bottom 211 that is roughly rectangular in plan view and faces the lid body 22, and four side wall portions 212 that stand upward from the edge of the bottom 211. On the other hand, the cover 22 is formed in the shape of a generally rectangular flat plate in plan view, having a size that includes a portion facing the upper end surface of the side wall portion 212 of the housing body 21.

[0037] Here, to facilitate the following explanation, the upper end surface of the side wall portion 212 of the housing body 21 and the portion of the lower surface of the lid body 22 facing the upper end surface of the side wall portion 212 are respectively referred to as the mating surface 21a of the housing body 21 (see Figure 1) and the mating surface 22a of the lid body 22 (see Figure 5), and the thickness direction of the side wall portion 212 of the housing body 21 is referred to as the width of the mating surface 21a.

[0038] As shown in FIG. 1, the four electromagnetic shielding gaskets 3 are conductive members interposed between the mating surface 21a of the housing main body 21 and the mating surface 22a of the lid body 22, and one is arranged on each of the upper end surfaces of the four side wall portions 212.

[0039] As shown in FIGS. 1 and 2, the electromagnetic shielding gasket 3 is formed in a strip shape that is short in the width direction X along the width of the mating surface 21a and long in the longitudinal direction Y along the outer shape of the housing main body 21, and is formed into a continuous wave shape along the longitudinal direction Y by corrugation processing.

[0040] The electromagnetic shielding gasket 3 has a wave-shaped configuration in which ridges extending from one side to the other in the width direction X are substantially perpendicular to the longitudinal direction Y in a plan view, and is formed into a wave-shaped configuration with a pitch P of 5 mm along the longitudinal direction Y and a height H of 3 mm (see FIG. 5).

[0041] As shown in FIG. 2, such an electromagnetic shielding gasket 3 is made of stainless steel expanded metal, and is formed so that its length in the width direction X is a predetermined width D that is narrower than the width of the mating surface 21a of the housing main body 21.

[0042] More specifically, the expanded metal that constitutes the electromagnetic shielding gasket 3 is a mesh member with roughly diamond-shaped openings (mesh) arranged in a staggered pattern, as shown in FIG. 3(a), and the roughly diamond-shaped openings (mesh) are formed by making cuts in a thin stainless steel plate and expanding it.

[0043] For example, as shown in Figure 3, the expanded metal is made of SUS316 and has a flat plate shape with a thickness T of 0.1 mm, and is formed into a mesh with a center-to-center distance SW in the short direction of 1.0 ± 0.15 mm, a center-to-center distance LW in the long direction of 2.0 ± 0.15 mm, and a pitch width W of 0.16 ± 0.03 mm. Furthermore, by forming the approximately diamond-shaped openings as described above, the expanded metal has a stepped cross-sectional shape in a longitudinal section taken along the short side, as shown in FIG. 3(b).

[0044] As shown in FIG. 4, the expanded metal constituting the electromagnetic shielding gasket 3, when expanded into a flat plate, has a rectangular shape in plan view that is wider than the predetermined width D, and includes a strip-shaped central portion 3a that extends in the longitudinal direction Y and has a length in the width direction X of a predetermined width D, and a pair of strip-shaped end portions 3b that extend in the longitudinal direction Y and have a length in the width direction X that is less than half the predetermined width D and are located on both sides of the central portion 3a in the width direction X.

[0045] The expanded metal constituting the electromagnetic shielding gasket 3 is formed so that its long direction substantially coincides with the width direction X and its short direction substantially coincides with the longitudinal direction Y, as shown in FIG.

[0046] As shown in FIG. 4, the electromagnetic shielding gasket 3 using the above-described expanded metal is formed by bending a pair of end portions 3b of the expanded metal, which is generally rectangular in plan view and wider than a predetermined width D, toward the other end portion 3b and overlapping it with a central portion 3a.

[0047] As a result, as shown in Figures 4 and 5, the electromagnetic shielding gasket 3 is configured to have a first contact portion 31 that contacts the mating surface 21a of the housing main body 21, two second contact portions 32 that contact the mating surface 22a of the lid body 22, and a bent portion 33 (see Figure 2) that is bent back from the end of the first contact portion 31 in the width direction X to the second contact portion 32.

[0048] Specifically, as shown in FIG. 4, the first contact portion 31 is a strip-shaped portion that is approximately rectangular in plan view, has a predetermined width D in the width direction X, and is long in the longitudinal direction Y, and is composed of a central portion 3a in the expanded shape when expanded into a flat plate.

[0049] As shown in FIG. 4, the two second contact portions 32 are strip-shaped portions that are approximately rectangular in plan view and have a length in the width direction X that is less than half of the predetermined width D and a length in the longitudinal direction Y that is approximately the same as that of the first contact portion 31, and are composed of a pair of end portions 3b in the unfolded shape.

[0050] The second contact portion 32 has an end portion 3b in its developed shape bent back toward one side of the first contact portion 31 in the thickness direction and toward the other second contact portion 32, and overlaps with the first contact portion 31. The length of the second contact portion 32 in the width direction X is set to be equal to or less than half of the predetermined width D so that the ends in the width direction X do not overlap each other when the second contact portion 32 is overlapped with the first contact portion 31.

[0051] As shown in FIG. 4, the bent-back portion 33 is a curved portion formed by bending back the end portion 3b in the unfolded shape, and constitutes the end portion of the electromagnetic shielding gasket 3 in the width direction X.

[0052] Next, as a method for manufacturing the electromagnetic shielding gasket 3, a method for manufacturing a plurality of electromagnetic shielding gaskets 3 (three electromagnetic shielding gaskets 3 in this embodiment) from one piece of expanded metal 4 will be described in further detail with reference to FIGS. 6 to 10.

[0053] FIG. 6 is an explanatory diagram illustrating the punching process, FIG. 7 is an explanatory diagram illustrating the first stage of the bending process, FIG. 8 is an explanatory diagram illustrating the second stage of the bending process, and FIG. 9 is an explanatory diagram illustrating the corrugating process.

[0054] Furthermore, Figure 10 is an explanatory diagram illustrating the cutting process, where Figure 10(a) shows an external perspective view of the corrugated expanded metal 4, and Figure 10(b) shows an external perspective view of the electromagnetic shielding gasket 3 in a cut-off state.

[0055] First, the manufacturing method of the electromagnetic shielding gasket 3 involves a punching step in which a single flat expanded metal sheet 4, which is arranged so that its long side coincides with the width direction X, is punched out with a predetermined die to form three unfolded electromagnetic shielding gaskets 3, as shown in FIG.

[0056] The specified mold is a mold that forms four openings S extending in the longitudinal direction Y at predetermined intervals in the width direction X, thereby forming an expanded electromagnetic shielding gasket 3 (strip-shaped portions 41 described later) in the flat expanded metal 4.

[0057] Specifically, as shown in FIG. 6 , the punching process involves punching a flat expanded metal sheet 4 with a predetermined die to form the flat expanded metal sheet 4 into a shape consisting of three strip-shaped portions 41 extending in the longitudinal direction Y at predetermined intervals in the width direction X, and an outer peripheral edge portion 42 that is a frame body that is approximately rectangular in plan view and connects both ends of the strip-shaped portions 41 in the longitudinal direction Y.

[0058] This strip-shaped portion 41 is an electromagnetic shielding gasket 3 in an unfolded shape, and is formed in a shape in which a central portion 41a, which becomes the first contact portion 31, is located in the center in the width direction X, and a pair of end portions 41b, which become the second contact portion 32, are located on both sides in the width direction X.

[0059] On the other hand, the outer peripheral edge portion 42 is composed of a pair of widthwise edge portions 42a extending in the widthwise direction X at a predetermined interval in the longitudinal direction Y, and a pair of longitudinal edge portions 42b connecting the ends of the widthwise edge portions 42a in the widthwise direction X to the longitudinal direction Y.

[0060] The ends of the three strip-shaped portions 41 in the longitudinal direction Y are connected to a pair of widthwise edges 42a of this outer peripheral edge portion 42. In other words, the three strip-shaped portions 41 arranged side by side in the widthwise direction X have both ends in the longitudinal direction Y connected via the widthwise edges 42a.

[0061] After the punching step is completed, the manufacturing method of the electromagnetic shielding gasket 3 includes a bending step in which the end portions 41b of the strip-shaped portions 41 are bent back and overlapped with the central portion 41a to form the first contact portion 31 and the second contact portion 32.

[0062] Specifically, as shown in FIG. 7, in the first stage of the bending process, the end portion 41b adjacent to the opening S is bent by extrusion toward one side in the thickness direction of the expanded metal 4 (to the lower side in the figure in this embodiment) so that the central portion 41a has a predetermined width D.

[0063] Furthermore, as shown in Figure 8, in the second stage of the bending process, the end portion 41b bent to one side in the plate thickness direction is bent back from one side in the plate thickness direction by press processing so as to overlap with the central portion 41a, thereby forming a first contact portion 31 of a predetermined width D and a second contact portion 32 overlapping the first contact portion 31.

[0064] After the bending process is completed, the manufacturing method of the electromagnetic shielding gasket 3 carries out a corrugating process in which the expanded metal 4 that has been bent back so that the strip-shaped portions 41 have a predetermined width D is corrugated into a wave shape with a pitch P of 5 mm and a height H of 3 mm by corrugating, as shown in FIG.

[0065] Specifically, as shown in FIG. 9 , in the corrugating process, a flat expanded metal 4 is fed in the longitudinal direction Y between a pair of corrugating rollers R having concaves and convexes that are capable of forming a circumferentially continuous corrugated shape with a pitch P of 5 mm and a height H of 3 mm, thereby forming a corrugated shape that is continuous in the longitudinal direction Y.

[0066] As a result, the flat expanded metal 4 is formed into a waveform shape that continues in the longitudinal direction Y as a whole, as shown in FIGS. After the corrugation process is completed, the manufacturing method of the electromagnetic shielding gasket 3 includes a cutting step of cutting the strip-shaped portions 41 from the width direction edge portions 42a of the outer peripheral edge portion 42, as shown in FIG.

[0067] Specifically, the manufacturing method of the electromagnetic shielding gasket 3 involves cutting the expanded metal 4 near the boundary between the widthwise edge 42a of the outer peripheral edge 42 and the strip-shaped portion 41, as shown in Figure 10(b), thereby cutting out three electromagnetic shielding gaskets 3 from one piece of expanded metal 4.

[0068] In this way, the manufacturing method of the electromagnetic shielding gasket 3 makes it possible to form a plurality of electromagnetic shielding gaskets 3 having appropriate rigidity and appropriate elasticity in the height direction of the corrugated shape from one sheet of expanded metal 4.

[0069] As described above, the electromagnetic shield gasket 3 of the first embodiment is interposed between the mating surfaces 21a, 22a of the housing body 21 and the cover 22 that constitute the housing 2 having electrical conductivity. This electromagnetic shielding gasket 3 has a first contact portion 31 that contacts the mating surface 21a of the housing main body 21, and a second contact portion 32 that overlaps the first contact portion 31 and contacts the mating surface 22a of the lid body 22.

[0070] The first contact portion 31 and the second contact portion 32 are formed by bending a thin expanded metal having a plate thickness T whose length in the width direction X is wider than a desired predetermined width D at the predetermined width D, and are formed into a continuous wave shape in the longitudinal direction Y that is perpendicular to the width direction X in a planar view.

[0071] Furthermore, the manufacturing method of the electromagnetic shielding gasket 3 in Example 1 includes a bending step in which a thin expanded metal having a plate thickness T whose length in the width direction X is wider than a desired predetermined width D is bent back at the predetermined width D to form a first contact portion 31 that contacts the mating surface 21 a of the housing main body 21 and a second contact portion 32 that overlaps the first contact portion 31 and contacts the mating surface 22 a of the lid body 22.

[0072] Furthermore, the manufacturing method of the electromagnetic shielding gasket 3 includes a corrugating step in which the overlapping first contact portion 31 and second contact portion 32 are corrugated together to form a continuous wave shape in the longitudinal direction Y that is perpendicular to the width direction X in a plan view.

[0073] According to this configuration, expanded metal wider than the specified width D is bent back to the specified width D and overlapped, and then formed into a continuous wave shape in the longitudinal direction Y, thereby allowing the gasket to have higher elasticity in the height direction of the wave shape than an electromagnetic shielding gasket composed only of a first contact portion 31 formed into a wave shape.

[0074] Therefore, when the electromagnetic shielding gasket 3 is pressed between the housing body 21 and the lid body 22, plastic deformation due to the pressing load is suppressed, and the contact state with both the housing body 21 and the lid body 22 can be maintained by elasticity.

[0075] This allows the electromagnetic shielding gasket 3 to stably secure contact points with the housing body 21 and the lid 22. Therefore, the electromagnetic shielding gasket 3 and the manufacturing method for the electromagnetic shielding gasket 3 can reduce variations in the state of contact with the housing body 21 and the lid 22, ensuring stable shielding performance.

[0076] In addition, since plastic deformation of the electromagnetic shield gasket 3 due to a pressing load can be suppressed, the electromagnetic shield gasket 3 and the method for manufacturing the electromagnetic shield gasket 3 can enable the electromagnetic shield gasket 3 to be reused.

[0077] The second contact portions 32 are formed so that the length in the width direction X is equal to or less than half of the predetermined width D, and are provided on both sides of the first contact portion 31 in the width direction X when the second contact portion 32 is unfolded into a flat plate. According to this configuration, the second contact portion 32 in the unfolded state is bent back to overlap the first contact portion 31, so that bent-back portions 33 can be formed at both ends in the width direction X by bending back. This makes it less likely that the electromagnetic shielding gasket 3 will get caught on another electromagnetic shielding gasket 3 or the clothing of a worker, compared to when both ends in the width direction X are end faces. This improves the ease of assembly when assembling the electromagnetic shielding gasket 3 to the housing 2.

[0078] The electromagnetic shield gasket 3 is formed so that the shorter direction of the expanded metal and the longitudinal direction Y are substantially aligned. With this configuration, the expanded metal has a continuous wave shape along the short side, so that the cross-sectional shapes of the first contact portion 31 and the second contact portion 32 in a vertical cross section along the longitudinal direction Y can be configured as a stepped cross-sectional shape of the expanded metal.

[0079] Therefore, the electromagnetic shield gasket 3 can have a plurality of contact points that come into contact with the housing body 21 and the cover 22 near the peaks and valleys of the wave shape due to the elasticity of the wave shape. This allows the electromagnetic shielding gasket 3 to be in more stable contact with the housing body 21 and the lid 22, thereby improving the shielding performance.

[0080] The center-to-center distance SW in the short direction of the expanded metal along the longitudinal direction Y is less than 1 / 2 pitch in the corrugated shape. With this configuration, the mesh size is smaller than half the pitch of the corrugated shape, preventing the peaks and valleys of the corrugated shape from becoming meshes of the expanded metal. This ensures that the electromagnetic shielding gasket 3 is in reliable contact with the housing body 21 and the lid 22, ensuring more stable shielding performance.

[0081] The manufacturing method of the electromagnetic shielding gasket 3 includes a punching step in which a thin sheet of expanded metal 4 having a thickness T is punched out with a predetermined die to form a shape in which a plurality of strip-shaped portions 41, each wider than a predetermined width D and extending in the longitudinal direction Y, are arranged side by side at predetermined intervals in the width direction X, and both ends of the plurality of strip-shaped portions 41 in the longitudinal direction Y are connected by widthwise edge portions 42a extending in the width direction X.

[0082] Furthermore, the manufacturing method of the electromagnetic shielding gasket 3 includes a bending process in which the strip-shaped portion 41 is bent back at a predetermined width D to form the first contact portion 31 and the second contact portion 32, and a corrugating process in which the expanded metal 4 having multiple strip-shaped portions 41 bent back at the predetermined width D is corrugated to form a continuous wave shape in the longitudinal direction Y. The manufacturing method of the electromagnetic shielding gasket 3 includes bending back the gasket at a predetermined width D and carrying out a cutting step of cutting the rectangular portions 41 formed into a wave shape from the widthwise edge portions 42a.

[0083] According to this configuration, multiple strip-shaped portions 41 bent back at a predetermined width D are corrugated while connected at the widthwise edge 42a, so that twisting of the strip-shaped portions 41 due to corrugation is suppressed compared to, for example, when strip-shaped portions 41 bent back at a predetermined width D and cut from the widthwise edge 42a are corrugated.

[0084] As a result, the manufacturing method of the electromagnetic shielding gasket 3 can prevent deterioration in the workability of assembling the electromagnetic shielding gasket 3 to the housing 2 due to twisting, and can suppress deterioration in the shielding performance of the electromagnetic shielding gasket 3 due to twisting.

[0085] In addition, the manufacturing method of the electromagnetic shielding gasket 3 allows multiple electromagnetic shielding gaskets 3 to be obtained at once from one piece of expanded metal 4, making it possible to efficiently form multiple electromagnetic shielding gaskets 3 with reduced twisting. [Example]

[0086] The electromagnetic shield gasket 5 of Example 2 is formed using expanded metal with a grain direction different from that of Example 1. Such an electromagnetic shield gasket 5 will be described with reference to FIG. FIG. 11 is a perspective view showing the appearance of the electromagnetic shield gasket 5 in the second embodiment.

[0087] As shown in FIG. 11, the electromagnetic shield gasket 5 of the second embodiment is formed in a long strip shape in the longitudinal direction Y, and is formed into a continuous wave shape along the longitudinal direction Y by corrugating. The electromagnetic shielding gasket 5 has a wave-shaped configuration in which the ridge lines extending from one side to the other in the width direction X are approximately perpendicular to the longitudinal direction Y in a plan view, and is formed into a wave-shaped configuration with a pitch P of 5 mm along the longitudinal direction Y and a height H of 3 mm.

[0088] The expanded metal constituting this electromagnetic shielding gasket 5 is made of SUS316, as in the above-mentioned Example 1, and is in the form of a flat plate with a plate thickness T of 0.1 mm, and is formed into a mesh with a center-to-center distance SW in the short direction of 1.0±0.15 mm, a center-to-center distance LW in the long direction of 2.0±0.15 mm, and a pitch width W of 0.16±0.03 mm. However, unlike in the first embodiment, the expanded metal constituting the electromagnetic shielding gasket 5 is formed so that the short direction substantially coincides with the width direction X and the long direction substantially coincides with the longitudinal direction Y.

[0089] As shown in FIG. 11, an electromagnetic shielding gasket 5 using such expanded metal is formed into a long strip shape in the longitudinal direction Y with the predetermined width D by bending a pair of end portions (symbols omitted) of the expanded metal, which is generally rectangular in plan view and wider than the predetermined width D, back toward the other end portion (symbols omitted) and overlapping them with the central portion (symbols omitted).

[0090] As a result, the electromagnetic shielding gasket 5 comprises a first contact portion 51 that contacts the mating surface 21a of the housing main body 21, two second contact portions 52 that contact the mating surface 22a of the lid body 22, and a bent portion 53 that is bent back from the end of the first contact portion 51 in the width direction X to the second contact portion 52.

[0091] The electromagnetic shield gasket 5 configured as described above, like the first embodiment, can suppress variations in the state of contact with the housing body 21 and the lid 22, and ensure stable shielding performance.

[0092] Furthermore, since the long direction of the expanded metal is formed so that it roughly coincides with the longitudinal direction Y, the electromagnetic shielding gasket 5 can suppress deformation of the mesh due to tensile load in the longitudinal direction Y compared to when the short direction and the longitudinal direction Y roughly coincide.

[0093] Therefore, when the electromagnetic shielding gasket 5 is formed, for example, into a continuous wave shape in the longitudinal direction Y, the mesh of the expanded metal is deformed, stretching in the longitudinal direction Y and preventing the gasket from becoming narrower than the desired specified width D.

[0094] Alternatively, when the electromagnetic shielding gasket 5 is formed into a continuous wave shape in the longitudinal direction Y, for example, it is possible to prevent the bonds of the expanded metal from breaking due to deformation of the mesh. As a result, the electromagnetic shielding gasket 5 can ensure stable conductivity even when the thin expanded metal is formed into a corrugated shape, thereby improving the shielding performance.

[0095] In correspondence between the configuration of this invention and the above-mentioned embodiment, The first member of the present invention corresponds to the housing body 21 of the embodiment, Similarly, The second member corresponds to the lid 22, One mating surface corresponds to the mating surface 21a of the housing body 21, The other mating surface corresponds to the mating surface 22a of the lid body 22, The center distance in the grain direction corresponds to the center distance SW in the short grain direction, The present invention is not limited to the configurations of the above-described embodiments, and many other embodiments can be obtained.

[0096] For example, in the above embodiment, the electronic device 1 is mounted on a vehicle such as an automobile, but the present invention is not limited to this and may be mounted on any suitable device. Furthermore, although the housing 2 has a generally rectangular shape in plan view, the shape is not limited to this, and the shape of the housing 2 may be any other suitable shape.

[0097] Furthermore, the housing 2 is configured with an approximately box-shaped housing main body 21 that is open at the top and a lid body 22 that covers the opening of the housing main body 21, but this is not limited to this, and the housing may be configured with an approximately box-shaped lower housing part that is open at the top and an approximately box-shaped upper housing part that is open at the bottom.

[0098] Furthermore, the expanded metal that constitutes the electromagnetic shielding gaskets 3 and 5 is made of stainless steel (more specifically, SUS316), but is not limited to this and may be made of any appropriate material as long as it is electrically conductive. Although not mentioned in the above embodiment, the expanded metal may be an expanded metal that has been subjected to a surface treatment such as a rust prevention treatment to improve rust prevention performance or a plating treatment to improve conductivity, or an expanded metal that has not been subjected to a surface treatment.

[0099] Further, the expanded metal has a thickness T of 0.1 mm, but this is merely an example and is not limiting, and the thickness T may be any appropriate thickness. Furthermore, although the expanded metal has a substantially diamond-shaped opening, the present invention is not limited to this, and may be an expanded metal having, for example, a tortoiseshell-shaped opening. Furthermore, the generally diamond-shaped opening is formed by cutting a slit in a thin plate and pushing it open, but this is not limited to this, and the generally diamond-shaped opening may be formed by cutting a slit in a thin plate and pulling it open.

[0100] In addition, the expanded metal has a center-to-center distance SW in the short direction of 1.0±0.15 mm, a center-to-center distance LW in the long direction of 2.0±0.15 mm, and an increment width W of 0.16±0.03 mm, but this is just an example and is not limited to this, and the center-to-center distance SW in the short direction, the center-to-center distance LW in the long direction, and the increment width W may be configured as appropriate. However, it is desirable that the distance between the centers of the grain along the longitudinal direction Y be less than half the pitch P in the wave shape in order to ensure contact between the mating surface 21a of the housing body 21 and the mating surface 22a of the lid body 22.

[0101] Furthermore, in Example 1, the electromagnetic shielding gasket 3 has the short grain direction of the expanded metal substantially aligned with the longitudinal direction Y, and in Example 2, the electromagnetic shielding gasket 5 has the long grain direction of the expanded metal substantially aligned with the longitudinal direction Y, but this is not limiting. For example, the electromagnetic shielding gasket may have both the short grain direction and the long grain direction of the expanded metal intersecting the longitudinal direction Y.

[0102] Furthermore, the waveform has a pitch P of 5 mm and a height H of 3 mm, but this is merely an example and is not limiting, and any waveform formed with an appropriate pitch P and height H may be used. Furthermore, the cross-sectional shape of the electromagnetic shield gaskets 3, 5 in a longitudinal section along the longitudinal direction Y is not limited to the above-described embodiment, as long as it is a wave-shaped shape that continues in the longitudinal direction Y.

[0103] For example, as shown in FIG. 12(a), which is an explanatory diagram illustrating the cross-sectional shape of an electromagnetic shielding gasket in another embodiment, the cross-sectional shape of the electromagnetic shielding gasket 3 in a longitudinal section along the longitudinal direction Y may be a wave-like shape with widely spaced peaks protruding upward and with substantially flat valleys. Alternatively, the cross-sectional shape of the electromagnetic shield gasket 3 in a longitudinal section along the longitudinal direction Y may be a wave shape with peaks of alternately different heights, as shown in FIG. 12(b).

[0104] Furthermore, although the wave-shaped shapes of the electromagnetic shielding gaskets 3 and 5 are such that the ridge lines extending from one side to the other in the width direction X intersect the longitudinal direction Y in plan view, the shape is not limited to this. For example, as shown in Fig. 13(a) which shows an external perspective view of the electromagnetic shielding gasket 6 and Fig. 13(b) which shows a plan view of the electromagnetic shielding gasket 6, the electromagnetic shielding gasket 6 may have a wave-shaped shape in which the ridge lines extending from one side to the other in the width direction X intersect the longitudinal direction Y in plan view. The thin lines in FIG. 13(b) are shown as lines indicating the boundaries of the arc portions of the wave-shaped shape in order to clarify the orientation of the ridge lines of the electromagnetic shielding gasket 6 in plan view.

[0105] In this case, when a single piece of flat expanded metal is punched out using a specified mold, the flat expanded metal is punched out so that the longitudinal direction Y of the electromagnetic shielding gasket 6 intersects with the longitudinal direction of the flat expanded metal, thereby forming the electromagnetic shielding gasket 6 in an expanded shape.

[0106] Furthermore, although the electromagnetic shielding gaskets 3 and 5 have a wave-shaped configuration that continues in the longitudinal direction Y, this is not limitative, and the electromagnetic shielding gasket may have a wave-shaped configuration that continues in both the width direction X and the longitudinal direction Y. Specifically, as shown in FIG. 13(c), the electromagnetic shield gasket 7 may have a longitudinal cross section along the width direction X in which the first contact portion 71 and the second contact portion 72 are integrally formed into a wavy shape that continues in the width direction X.

[0107] This electromagnetic shielding gasket 7 is made by forming an expanded metal, with a pair of end portions overlapping at the center, into a continuous wave shape in the width direction X by corrugating, and then forming it into a continuous wave shape in the longitudinal direction Y by corrugating. The waveforms continuing in the width direction X have a smaller pitch and a lower height than the waveforms continuing in the longitudinal direction Y.

[0108] In addition, the configuration is such that two second contact portions 32 narrower than the first contact portion 31 are overlapped on the first contact portion 31 of a predetermined width D, but this is not limited to this, and the configuration may also be such that the first contact portion 31 and the second contact portion 32 having approximately the same length in the width direction X are overlapped.

[0109] For example, in the unfolded state, the electromagnetic shield gasket 3A may be such that the second contact portion 34 of a predetermined width D provided on one end side of the first contact portion 31 in the width direction X is bent back toward the other side in the width direction X and overlapped with the first contact portion 31, as shown in FIG. 14(a) which is an explanatory diagram illustrating an electromagnetic shield gasket in another embodiment.

[0110] Alternatively, the electromagnetic shielding gasket 3B may be formed by folding back an expanded metal in a three-fold manner so that the second contact portion 35 overlaps the first contact portion 31 with the non-contact portion 36 sandwiched between them, as shown in FIG. 14(b). The expanded metal has, in an unfolded state, a second contact portion 35 of a predetermined width D on one side of the first contact portion 31 in the width direction X, and a non-contact portion 36 that does not contact the housing 2 on the other side of the first contact portion 31 in the width direction X.

[0111] Alternatively, the electromagnetic shielding gasket 3C may be formed by folding back an expanded metal in three directions (also called a Z-fold, an accordion fold, or a zigzag fold) so that the second contact portion 38 overlaps the first contact portion 31 with the non-contact portion 37 sandwiched between them, as shown in FIG. 14(c). The expanded metal has a non-contact portion 37 that does not contact the housing 2 and a second contact portion 38 of a predetermined width D, in that order, on one side of the first contact portion 31 in the width direction X when in an unfolded state.

[0112] Furthermore, although the electromagnetic shielding gasket 3 is in the form of a long strip in the longitudinal direction Y, this is not limited to this, and the electromagnetic shielding gasket may be, for example, an approximately L-shaped gasket in a plan view, as long as it can be formed into a wave-shaped shape along the longitudinal direction Y. Alternatively, as shown in FIG. 15 which is an explanatory view illustrating an electromagnetic shield gasket according to another embodiment, the electromagnetic shield gasket 8 may be substantially annular in plan view along the mating surfaces 21a, 22a of the housing 2.

[0113] In the case of an electromagnetic shielding gasket that is generally L-shaped in plan view or an electromagnetic shielding gasket 8 that is generally annular in plan view, as shown in FIG. 15, the ridge lines extending from one side to the other in the direction along the width of the mating surfaces 21 a, 22 a are formed in a wave shape that intersects in plan view with a direction that is generally perpendicular to the width of the mating surfaces 21 a, 22 a. That is, in the case of an electromagnetic shielding gasket that is generally L-shaped in plan view or an electromagnetic shielding gasket 8 that is generally annular in plan view, the ridge line extending from one side to the other in the width direction X is formed into a wave-like shape that intersects with the longitudinal direction Y in plan view.

[0114] In addition, after the bending process in which a thin expanded metal having a plate thickness T wider than the predetermined width D is bent back to form the first contact portion 31 and the second contact portion 32, a corrugating process is performed in which the overlapping first contact portion 31 and second contact portion 32 are corrugated together to form a continuous wave shape in the longitudinal direction Y, but this is not limited to this.

[0115] For example, after a corrugating process in which a thin expanded metal having a plate thickness T wider than a predetermined width D is corrugated to form a continuous wave shape in the longitudinal direction Y, a bending process may be performed in which the expanded metal formed into a wave shape is bent back at a predetermined width D to form the first contact portion 31 and the second contact portion 32.

[0116] Furthermore, by bending back a pair of end portions 3b of the expanded metal, which is generally rectangular in plan view and wider than the predetermined width D, to form bent-back portions 33, it is less likely to get caught on other electromagnetic shielding gaskets 3, 5 or the clothing of a worker, but this is not limited to this.

[0117] For example, as shown in FIG. 16(a) which is an explanatory diagram illustrating an electromagnetic shielding gasket according to another embodiment, both ends of the electromagnetic shielding gasket 9A in the width direction X may be curved by curling to make it less likely to get caught on another electromagnetic shielding gasket or the clothing of a worker. Alternatively, as shown in FIG. 16(b), beads 91 extending in the longitudinal direction Y may be formed on both widthwise ends of the electromagnetic shielding gasket 9B to prevent it from getting caught on another electromagnetic shielding gasket or the clothing of a worker. [Explanation of symbols]

[0118] 2. Housing 3, 3A, 3B, 3C, 5, 6, 7, 8, 9A, 9B...Electromagnetic shielding gasket 4...Expanded metal 21...Main body 21a...Mating surface 22...lid body 22a...Mating surface 31,51,71...1st contact part 32,34,35,38,52,72…Second contact part 41...Rectangular section 42a…Width direction edge D...Predetermined width SW: Center distance in the short direction X…Width direction Y: Longitudinal direction

Claims

1. An electromagnetic shielding gasket interposed between a mating surface of a first member and a second member that constitute a conductive housing, a first contact portion that contacts one of the mating surfaces; a second contact portion that overlaps the first contact portion and contacts the other mating surface, The direction along the width of the mating surface is defined as the width direction, The first contact portion and the second contact portion are The expanded metal is formed by bending back a thin expanded metal sheet having a width greater than a predetermined width in the width direction at the predetermined width, and is formed into a continuous wave shape in the longitudinal direction perpendicular to the width direction in a plan view. Electromagnetic shielding gasket.

2. the second contact portions are provided on both sides of the first contact portion in the width direction when the first contact portion is unfolded into a flat plate; Each of the second contact portions is formed so that the length in the width direction is equal to or less than half of the predetermined width.

2. The electromagnetic shielding gasket according to claim 1.

3. The expanded metal is formed so that the short direction and the long direction thereof are substantially aligned with each other.

2. The electromagnetic shielding gasket according to claim 1.

4. The expanded metal is formed so that its longitudinal direction substantially coincides with the longitudinal direction.

2. The electromagnetic shielding gasket according to claim 1.

5. The center-to-center distance in the short or long direction of the expanded metal along the longitudinal direction is a distance less than 1 / 2 pitch of the corrugated shape.

2. The electromagnetic shielding gasket according to claim 1.

6. A method for manufacturing an electromagnetic shielding gasket interposed between a mating surface of a first member and a second member that constitute a conductive housing, comprising: The direction along the width of the mating surface is defined as the width direction, a bending step of bending back a thin expanded metal sheet, the width of which is wider than a predetermined desired width, at the predetermined width to form a first contact portion that contacts one of the mating surfaces and a second contact portion that overlaps the first contact portion and contacts the other mating surface; a corrugating step of integrally corrugating the overlapped first contact portion and the second contact portion to form a continuous wave shape in a longitudinal direction perpendicular to the width direction in a plan view. Manufacturing method for electromagnetic shielding gaskets.

7. a punching process in which a single sheet of the expanded metal having a thin plate thickness is punched out with a predetermined die to form a shape in which a plurality of strip-shaped portions wider than the predetermined width and extending in the longitudinal direction are arranged side by side at predetermined intervals in the width direction, and both ends in the longitudinal direction of the plurality of strip-shaped portions are connected by widthwise edge portions extending in the width direction; a bending step of bending the strip-shaped portion at the predetermined width to form the first contact portion and the second contact portion; a corrugating step of corrugating the expanded metal having the plurality of strip-shaped portions bent back at the predetermined width to form the corrugated shape that is continuous in the longitudinal direction; a cutting step of cutting the rectangular portion bent back at the predetermined width and formed into the wave shape from the edge portion in the width direction. A method for manufacturing the electromagnetic shielding gasket according to claim 6.

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