Electromagnetic shielding gasket, and method for manufacturing an electromagnetic shielding gasket.

Abstract

The objective is to provide an electromagnetic shielding gasket 3 and a method for manufacturing the electromagnetic shielding gasket 3 that can suppress variations in contact conditions with the housing body 21 and the lid 22, thereby ensuring stable shielding performance. [Solution] An electromagnetic shielding gasket 3 interposed at the mating surface between a housing body 21 and a lid 22 that constitute a conductive housing 2, comprising 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 22, wherein the first contact portion 31 and the second contact portion 32 are formed by bending a thin expanded metal with a thickness T whose length in the width direction X is wider than a desired predetermined width D at a predetermined width D, and are formed in a corrugated shape that is continuous in the longitudinal direction Y which is perpendicular to the width direction X in a plan view.

Description

Technical Field

[0001] The present invention relates to an electromagnetic shielding gasket that blocks leakage of electromagnetic waves generated inside an electronic device to the outside, or intrusion of leakage electromagnetic waves generated by another electronic device into the electronic device, and a method for manufacturing the electromagnetic shielding gasket.

Background Art

[0002] For example, in electric vehicles such as electric cars and hybrid cars, a large number of electronic devices are installed. When such electronic devices are in an energized state, electromagnetic waves are radiated from the electronic circuits and electronic components housed inside. However, for example, if the electromagnetic waves leak as leakage electromagnetic waves from the electronic device, there is a risk of acting as noise on surrounding electronic devices.

[0003] Therefore, in an electronic device, a housing is made of a conductive material, and an electromagnetic shielding gasket is interposed between a first member and a second member that make up the housing, thereby blocking leakage of electromagnetic waves from the gap between the first member and the second member and intrusion of leakage electromagnetic waves through the gap between the first member and the second member to ensure shielding performance. As such an electromagnetic shielding gasket, for example, as described in Patent Document 1, an electromagnetic shielding gasket made of an expandable metal having conductivity is known.

[0004] By the way, since Patent Document 1 constitutes the electromagnetic shielding gasket with a thin flat expandable metal, when the electromagnetic shielding gasket is pressed by the first member and the second member, the electromagnetic shielding gasket is likely to plastically deform.

[0005] Then, in the electromagnetic shielding gasket of Patent Document 1, there is a problem that stable shielding performance cannot be ensured because there may be variations in the contact state with respect to both the first member and the second member due to plastic deformation.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Microfilm of Utility Model Application No. 63-088621 (Utility Model Publication No. 02-9500) [Overview of the project] [Problems that the invention aims to solve]

[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 suppress variations in the contact state with the first member and the second member and ensure stable shielding performance. [Means for solving the problem]

[0008] This invention relates to an electromagnetic shielding gasket interposed at the mating surface between a first member and a second member constituting a conductive housing, comprising 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, wherein the first contact portion and the second contact portion are formed by bending a thin expanded metal sheet, whose length in the width direction is wider than a desired predetermined width, at the predetermined width, and are formed in a corrugated shape that is continuous in the longitudinal direction perpendicular to the width direction in a plan view.

[0009] Furthermore, this invention relates to a method for manufacturing an electromagnetic shielding gasket interposed at the mating surface between a first member and a second member constituting a conductive housing, characterized by a bending step in which a thin expanded metal sheet, wider than a desired predetermined width and with the width direction being the width direction, is bent back to 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, and a corrugation step in which the overlapping first contact portion and the second contact portion are integrally corrugated to form a corrugated shape that is continuous in the longitudinal direction perpendicular to the width direction in a plan view.

[0010] "Overlapping the first contact portion" means either directly overlapping the first contact portion, or indirectly overlapping the first contact portion with a non-contact portion in between that does not contact either the first or second member. The above-mentioned expanded metal refers to a component formed by pressing and expanding a conductive thin sheet while making cuts, with multiple meshes arranged in a staggered pattern, or a component formed by stretching and expanding a conductive thin sheet while making cuts, with multiple meshes arranged in a staggered pattern.

[0011] The expanded metal may be expanded metal that has undergone surface treatment such as rust prevention treatment to improve corrosion resistance or plating treatment to improve conductivity, or expanded metal that has not undergone any surface treatment. The above-mentioned wave-like shape that is continuous in the longitudinal direction refers to a shape in which the ridges extending from one side in the width direction to the other side are approximately perpendicular to the longitudinal direction in a plan view, or a shape in which the ridges extending from one side in the width direction to the other side intersect the longitudinal direction in a plan view.

[0012] According to this invention, by bending expanded metal wider than a predetermined width back to a predetermined width and overlapping them, and forming a continuous corrugated shape in the longitudinal direction, it is possible to achieve higher elasticity in the height direction of the corrugated shape compared to an electromagnetic shielding gasket composed only of a first contact portion formed in a corrugated 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 contact state with both the first and second members can be maintained elastically.

[0014] As a result, the electromagnetic shielding gasket can stably ensure contact with the first and second members. Therefore, the electromagnetic shielding gasket and the method for manufacturing the electromagnetic shielding gasket can suppress variations in the contact state with the first and second members and ensure stable shielding performance.

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

[0016] In this embodiment of the invention, the second contact portion is, In the unfolded state, which is spread out into a plate shape, the first contact portion is provided on both sides in the width direction. Each of the second contact portions is formed such that its length in the width direction is less than or equal to half of the predetermined width. That's fine.

[0017] With this configuration, the second contact portion in the unfolded state is bent back and superimposed on the first contact portion, so that bent portions can be formed at both ends in the width direction. This makes the electromagnetic shielding gasket less likely to snag on other electromagnetic shielding gaskets or the worker's clothing compared to a gasket with end faces at both ends in the width direction. Therefore, the ease of assembly when installing the electromagnetic shielding gasket into the housing can be improved.

[0018] In another aspect of this invention, the expanded metal may be formed such that its short direction and its long direction substantially coincide. With this configuration, the expanded metal has a continuous corrugated shape along its shorter direction, allowing the cross-sectional shapes of the first and second contact portions in the longitudinal section along the longer direction to be configured with a stepped cross-sectional shape of the expanded metal.

[0019] Therefore, the electromagnetic shielding gasket can have multiple contact points that contact the first member and the second member due to the elasticity of the corrugated shape, located near the peaks and troughs of the corrugated shape. As a result, the electromagnetic shielding gasket can stabilize its contact with the first and second members, thereby improving its shielding performance.

[0020] As an aspect of the present invention, the long side direction of the expanded metal may be formed to substantially coincide with the longitudinal direction. According to this configuration, deformation of the mesh due to the tensile load in the longitudinal direction can be suppressed as compared with the case where the short side direction and the longitudinal direction substantially coincide.

[0021] Therefore, when the electromagnetic shielding gasket is formed into a waveform shape continuous in the longitudinal direction, for example, it is possible to prevent the mesh of the expanded metal from being deformed and extending in the longitudinal direction to become narrower than a desired predetermined width.

[0022] Alternatively, when the electromagnetic shielding gasket is formed into a waveform shape continuous in the longitudinal direction, for example, it is possible to prevent the bond of the expanded metal from being broken due to deformation of the mesh. As a result, the electromagnetic shielding gasket can ensure stable conductivity even when the thin expanded metal is formed into a waveform shape, so that the shielding performance can be improved.

[0023] As an aspect of the present invention, the short mesh direction Or in the longer direction center-to-center distance of the expanded metal along the longitudinal direction may be a distance less than 1 / 2 pitch in the waveform shape. According to this configuration, since the size of the mesh is smaller than 1 / 2 pitch of the waveform shape, it is possible to prevent the top and bottom portions of the waveform shape from becoming the mesh of the expanded metal. As a result, the electromagnetic shielding gasket can surely contact the first member and the second member, so that more stable shielding performance can be ensured.

[0024] Furthermore, in an embodiment of this invention, the method for manufacturing an electromagnetic shielding gasket is a punching step in which a thin sheet of expanded metal is punched out with a predetermined die to form a shape in which a plurality of strip-shaped portions, wider than a predetermined width and extending in the longitudinal direction, are arranged side by side at predetermined intervals in the width direction, and the longitudinal ends of the plurality of strip-shaped portions are connected by width-direction edges that extend in the width direction; a bending step in which the strip-shaped portions are bent back to the predetermined width to form the first contact portion and the second contact portion; a corrugating step in which the expanded metal having the plurality of strip-shaped portions bent back to the predetermined width is corrugated to form the corrugated shape that is continuous in the longitudinal direction; and a bending step in which the strip-shaped portions are bent back to the predetermined width So The process may also involve a cutting step in which the strip-shaped portion formed in the wave shape is cut from the widthwise edge.

[0025] With this configuration, multiple strip-shaped sections bent back to a predetermined width are connected at their widthwise edges and then corrugated. This reduces the amount of twisting that occurs in the strip-shaped sections due to the corrugation process, compared to, for example, when strip-shaped sections are bent back to a predetermined width and then cut from their widthwise edges before corrugation.

[0026] Therefore, the method for manufacturing electromagnetic shielding gaskets can prevent a decrease in the ease of assembly of the electromagnetic shielding gasket to the housing due to twisting, and can also suppress a decrease in shielding performance due to twisting of the electromagnetic shielding gasket.

[0027] In addition, the method for manufacturing electromagnetic shielding gaskets allows for the production of multiple electromagnetic shielding gaskets from a single piece of expanded metal at once, thus enabling the efficient construction of multiple electromagnetic shielding gaskets with suppressed twisting. [Effects of the Invention]

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

[0029] [Figure 1] An exploded perspective view showing the external appearance of electronic equipment in a disassembled state. [Figure 2] An external perspective view showing the appearance of the electromagnetic shielding gasket. [Figure 3] An explanatory diagram illustrating expanded metal. [Figure 4] An explanatory diagram illustrating the configuration of an electromagnetic shielding gasket. [Figure 5] A cross-sectional view showing the cross-section of an electromagnetic shielding gasket in a longitudinal section along the length direction. [Figure 6] An explanatory diagram illustrating the punching process. [Figure 7] An explanatory diagram illustrating the first stage of the bending process. [Figure 8] An explanatory diagram illustrating the second stage of the bending process. [Figure 9] An explanatory diagram illustrating the corrugation process. [Figure 10] An explanatory diagram illustrating the cutting process. [Figure 11] An external perspective view showing the appearance of the electromagnetic shielding gasket in Example 2. [Figure 12] An explanatory diagram illustrating the cross-sectional shape of an electromagnetic shielding gasket in another embodiment. [Figure 13] An explanatory diagram illustrating an electromagnetic shielding gasket in another embodiment. [Figure 14] An explanatory diagram illustrating an electromagnetic shielding gasket in another embodiment. [Figure 15] An explanatory diagram illustrating an electromagnetic shielding gasket in another embodiment. [Figure 16] An explanatory diagram illustrating an electromagnetic shielding gasket in another embodiment. [Modes for carrying out the invention]

[0030] One embodiment of this invention will be described below with reference to the drawings. [Examples]

[0031] In Example 1, an electromagnetic shielding gasket 3 that seals the gaps in the housing 2 of the electronic device 1 to block the leakage of electromagnetic waves and the intrusion of leakage electromagnetic waves will be explained using Figures 1 to 5.

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

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

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

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

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

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

[0038] Furthermore, as shown in Figure 1, the four electromagnetic shielding gaskets 3 are conductive members interposed between the mating surface 21a of the housing body 21 and the mating surface 22a of the lid 22, with one gasket positioned for each of the four upper end surfaces of the side wall portions 212.

[0039] As shown in Figures 1 and 2, the electromagnetic shielding gasket 3 is formed in a strip shape with a short width X along the width of the mating surface 21a and a long longitudinal Y along the outer shape of the housing body 21, and is formed into a continuous corrugated shape along the longitudinal Y by a corrugation process.

[0040] The electromagnetic shielding gasket 3 has a corrugated shape in which the ridges extending from one side to the other in the width direction X are approximately perpendicular to the longitudinal direction Y in a plan view. For example, it is formed with a corrugated shape with a pitch P of 5 mm and a height H of 3 mm along the longitudinal direction Y (see Figure 5).

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

[0042] To elaborate, the expanded metal constituting the electromagnetic shielding gasket 3 is a mesh member with roughly diamond-shaped openings (mesh) arranged in a staggered pattern, as shown in Figure 3(a). The roughly diamond-shaped openings (mesh) are formed by cutting and expanding a thin stainless steel plate.

[0043] For example, as shown in Figure 3, the expanded metal is made of SUS316 material, has a plate thickness T of 0.1 mm, is flat, and is formed to have 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 mesh width W of 0.16 ± 0.03 mm. Furthermore, by forming a roughly diamond-shaped opening as described above, the expanded metal has a stepped cross-sectional shape in the longitudinal section along the shorter direction, as shown in Figure 3(b).

[0044] As shown in Figure 4, the expanded metal constituting the electromagnetic shield gasket 3, when unfolded into a flat plate shape, is formed in a roughly rectangular shape in plan view, wider than the predetermined width D, by a strip-shaped central portion 3a that extends in the longitudinal direction Y with 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 with a length in the width direction X of less than half the predetermined width D and are located on both sides of the width direction X of the central portion 3a.

[0045] Furthermore, as shown in Figure 4, the expanded metal constituting the electromagnetic shielding gasket 3 is formed such that its longitudinal direction approximately coincides with the width direction X, and its short direction approximately coincides with the longitudinal direction Y.

[0046] As shown in Figure 4, the electromagnetic shielding gasket 3 using the expanded metal described above has a pair of end portions 3b of an expanded metal that is wider than a predetermined width D and is roughly rectangular in plan view, which are bent back toward the other end portion 3b and overlapped with the central portion 3a.

[0047] As a result, the electromagnetic shield gasket 3, as shown in Figures 4 and 5, consists of a first contact portion 31 that contacts the mating surface 21a of the housing body 21, two second contact portions 32 that contact the mating surface 22a of the lid 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 Figure 4, the first contact portion 31 is a strip-shaped portion in plan view that is roughly rectangular in length X in the width direction and long in the longitudinal direction Y, and is composed of the central portion 3a in the unfolded shape when it is unfolded into a flat plate shape.

[0049] Furthermore, as shown in Figure 4, the two second contact portions 32 are strip-shaped portions in a plan view that are roughly rectangular, with a length in the width direction X being less than or equal to half of the predetermined width D and a length in the longitudinal direction Y being roughly 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] This second contact portion 32 is formed by bending the end portion 3b in the unfolded shape toward one side of the first contact portion 31 in the thickness direction toward the other second contact portion 32, and overlapping it with the first contact portion 31. Furthermore, when the second contact portion 32 overlaps with the first contact portion 31, the length in the width direction X is set to be less than half of the predetermined width D so that the ends in the width direction X do not overlap with each other.

[0051] Furthermore, as shown in Figure 4, the bent portion 33 is a curved portion formed by bending the end portion 3b in the unfolded shape, and constitutes the end portion in the width direction X of the electromagnetic shield gasket 3.

[0052] Next, as a method for manufacturing electromagnetic shielding gaskets 3, a manufacturing method for producing multiple electromagnetic shielding gaskets 3 (three electromagnetic shielding gaskets 3 in this embodiment) from a single expanded metal 4 will be described in more detail using Figures 6 to 10.

[0053] Figure 6 shows an explanatory diagram illustrating the punching process, Figure 7 shows an explanatory diagram illustrating the first stage of the bending process, Figure 8 shows an explanatory diagram illustrating the second stage of the bending process, and Figure 9 shows an explanatory diagram illustrating the corrugation process.

[0054] Furthermore, Figure 10 is an explanatory diagram illustrating the cutting process, with Figure 10(a) showing an external perspective view of the corrugated expanded metal 4, and Figure 10(b) showing an external perspective view of the electromagnetic shielding gasket 3 after it has been detached.

[0055] First, as shown in Figure 6, the manufacturing method for the electromagnetic shielding gasket 3 involves a punching process in which a single flat expanded metal sheet 4, arranged so that its length is the width X, is punched out using a predetermined die to form three unfolded shapes of electromagnetic shielding gaskets 3.

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

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

[0058] This strip-shaped portion 41 is an unfolded electromagnetic shielding gasket 3, and is formed in such a shape that a central portion 41a, which becomes a first contact portion 31, is located in the center in the width direction X, and a pair of end portions 41b, which become second contact portions 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 that extend in the widthwise direction X at predetermined intervals in the longitudinal direction Y, and a pair of longitudinal edge portions 42b that connect 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 sections 41 in the longitudinal direction Y are connected to a pair of widthwise edges 42a on the outer peripheral edge 42. In other words, the three strip-shaped sections 41, which are arranged side by side in the widthwise direction X, are connected at both ends in the longitudinal direction Y via the widthwise edges 42a.

[0061] Once the punching process is complete, the manufacturing method of the electromagnetic shield gasket 3 involves a bending process in which the end portion 41b of the strip-shaped portion 41 is 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 Figure 7, the bending process begins with the first step of bending the end portion 41b adjacent to the opening S toward one side (the lower side in this embodiment) in the thickness direction of the expanded metal 4 by extrusion so that the central portion 41a has a predetermined width D.

[0063] Furthermore, as shown in Figure 8, the bending process, in the second stage, involves bending the end portion 41b that has been folded to one side in the thickness direction back by press working so that it overlaps with the central portion 41a from one side in the thickness direction, thereby forming a first contact portion 31 of a predetermined width D and a second contact portion 32 that overlaps the first contact portion 31.

[0064] Once the bending process is complete, the manufacturing method of the electromagnetic shield gasket 3, as shown in Figure 9, involves a corrugation process in which the expanded metal 4, which has been bent back so that the strip-shaped portion 41 has a predetermined width D, is corrugated into a corrugated shape with a pitch P=5 mm and a height H=3 mm by corrugation processing.

[0065] Specifically, as shown in Figure 9, the corrugation process involves feeding a flat expanded metal 4 along the longitudinal direction Y between a pair of corrugation rollers R that have continuous circumferential and uneven surfaces capable of forming a corrugated shape with a pitch P=5mm and a height H=3mm, 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 corrugated shape that is continuous in the longitudinal direction Y, as shown in Figures 9 and 10(a). Once the corrugation process is complete, the manufacturing method of the electromagnetic shield gasket 3 involves a cutting step, as shown in Figure 10, in which the strip-shaped portion 41 is cut from the widthwise edge portion 42a of the outer peripheral edge portion 42.

[0067] Specifically, as shown in Figure 10(b), the manufacturing method for 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, thereby cutting out three electromagnetic shielding gaskets 3 from a single piece of expanded metal 4, and completing all the steps.

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

[0069] As described above, the electromagnetic shielding gasket 3 of Example 1 is interposed at the mating surfaces 21a and 22a between the housing body 21 and the lid 22 that constitute the conductive housing 2. This electromagnetic shielding gasket 3 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 with the first contact portion 31 and also contacts the mating surface 22a of the lid 22.

[0070] The first contact portion 31 and the second contact portion 32 are formed by bending a thin expanded metal sheet with a thickness T that is wider than a desired predetermined width D in the width direction X, and are formed in a corrugated shape that is continuous in the longitudinal direction Y which is perpendicular to the width direction X in a plan view.

[0071] Furthermore, the manufacturing method of the electromagnetic shield gasket 3 in Example 1 involves a bending process in which a thin expanded metal sheet with a thickness T and a length X in the width direction 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 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 22.

[0072] Furthermore, the manufacturing method of the electromagnetic shield gasket 3 involves a corrugation process in which the overlapping first contact portion 31 and second contact portion 32 are integrally corrugated to form a corrugated shape that is continuous in the longitudinal direction Y, which is perpendicular to the width direction X in a plan view.

[0073] With this configuration, by bending expanded metal wider than a predetermined width D back to the predetermined width D and overlapping them, and forming a corrugated shape continuous in the longitudinal direction Y, it is possible to achieve higher elasticity in the height direction of the corrugated shape compared to an electromagnetic shielding gasket composed only of a first contact portion 31 formed in a corrugated shape.

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

[0075] As a result, the electromagnetic shielding gasket 3 can stably ensure contact with the housing body 21 and the lid 22. Therefore, the electromagnetic shielding gasket 3 and the method for manufacturing the electromagnetic shielding gasket 3 can suppress variations in the contact state with the housing body 21 and the lid 22, thereby ensuring stable shielding performance.

[0076] In addition, because plastic deformation of the electromagnetic shielding gasket 3 due to pressing load can be suppressed, the electromagnetic shielding gasket 3 and the method for manufacturing the electromagnetic shielding gasket 3 can enable the reuse of the electromagnetic shielding gasket 3.

[0077] Furthermore, the second contact portion 32 is formed with a length in the width direction X of the first contact portion 31 that is less than or equal to half of the predetermined width D, and is provided on both sides of the width direction X of the first contact portion 31 when it is unfolded into a flat plate shape. With this configuration, the second contact portion 32 in the unfolded state is bent back and superimposed on the first contact portion 31, so that bent-back portions 33 can be formed at both ends in the width direction X. As a result, the electromagnetic shielding gasket 3 is less likely to snag on other electromagnetic shielding gaskets 3 or the worker's clothing compared to a gasket where both ends in the width direction X are end faces. Therefore, the electromagnetic shielding gasket 3 can be assembled to the housing 2 with improved ease of installation.

[0078] Furthermore, the electromagnetic shielding gasket 3 is formed such that the short direction and the long direction Y of the expanded metal are approximately coincident. With this configuration, the expanded metal has a continuous corrugated shape along its shorter direction, so the cross-sectional shapes of the first contact portion 31 and the second contact portion 32 in the longitudinal section along the longitudinal direction Y can be configured with a stepped cross-sectional shape of the expanded metal.

[0079] Therefore, the electromagnetic shielding gasket 3 can have multiple contacts that contact the housing body 21 and the lid 22 due to the elasticity of its corrugated shape, located near the peaks and valleys of the corrugated shape. As a result, the electromagnetic shielding gasket 3 can stabilize its contact with the housing body 21 and the lid 22, thereby improving the shielding performance.

[0080] Furthermore, the distance SW between the centers in the short direction of the expanded metal along the longitudinal direction Y is less than half the pitch in the corrugated shape. With this configuration, the mesh size is smaller than half the pitch of the corrugated shape, which prevents the peaks and valleys of the corrugated shape from becoming part of the expanded metal mesh. As a result, the electromagnetic shielding gasket 3 makes secure contact with the housing body 21 and the cover 22, ensuring more stable shielding performance.

[0081] Furthermore, the manufacturing method of the electromagnetic shield gasket 3 involves a punching process in which a thin sheet of expanded metal 4 with a thickness T is punched out with a predetermined die to form a shape in which multiple strip-shaped portions 41 that are wider than a predetermined width D and extend in the longitudinal direction Y are arranged side by side at predetermined intervals in the width direction X, and both ends of the multiple strip-shaped portions 41 in the longitudinal direction Y are connected by width-direction edges 42a that extend in the width direction X.

[0082] Furthermore, the method for manufacturing the electromagnetic shield gasket 3 includes a bending step of bending the strip-shaped portion 41 back to a predetermined width D to form the first contact portion 31 and the second contact portion 32, and a corrugation step of corrugating the expanded metal 4 having a plurality of strip-shaped portions 41 bent back to a predetermined width D to form a corrugated shape continuous in the longitudinal direction Y. The manufacturing method for the electromagnetic shield gasket 3 involves bending it back to a predetermined width D and performing a cutting step in which the corrugated strip-shaped portion 41 is cut from the widthwise edge portion 42a.

[0083] With this configuration, multiple strip-shaped portions 41 that have been bent back at a predetermined width D are connected at the widthwise edge portions 42a and then corrugated. Therefore, compared to, for example, a case where strip-shaped portions 41 that have been bent back at a predetermined width D and cut from the widthwise edge portions 42a are corrugated, twisting associated with corrugation of the strip-shaped portions 41 can be suppressed.

[0084] Therefore, the manufacturing method of the electromagnetic shielding gasket 3 can prevent a decrease in the ease of assembly of the electromagnetic shielding gasket 3 to the housing 2 due to twisting, and can suppress a decrease in shielding performance due to twisting of the electromagnetic shielding gasket 3.

[0085] In addition, the manufacturing method for the electromagnetic shielding gasket 3 allows for the production of multiple electromagnetic shielding gaskets 3 from a single expanded metal 4 at once, thus enabling the efficient construction of multiple electromagnetic shielding gaskets 3 with suppressed twisting. [Examples]

[0086] The electromagnetic shielding gasket 5 of Example 2 is formed using expanded metal with a different grain direction than that of Example 1 described above. This electromagnetic shielding gasket 5 will be explained with reference to Figure 11. Figure 11 shows an external perspective view of the electromagnetic shielding gasket 5 in Example 2.

[0087] As shown in Figure 11, the electromagnetic shielding gasket 5 of Example 2 is formed in a long, rectangular shape in the longitudinal direction Y, and is also formed into a continuous corrugated shape along the longitudinal direction Y by a corrugation process. The electromagnetic shielding gasket 5 has a corrugated shape in which the ridges extending from one side to the other in the width direction X are approximately perpendicular to the longitudinal direction Y in a plan view. For example, it is formed with a corrugated shape in which the pitch P along the longitudinal direction Y is 5 mm and the height H is 3 mm.

[0088] The expanded metal constituting this electromagnetic shielding gasket 5 is, as in the above-described embodiment 1, made of SUS316 material, flat in shape with a plate thickness T of 0.1 mm, and formed to have 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 mesh with a mesh width W of 0.16 ± 0.03 mm. However, unlike in Example 1, the expanded metal constituting the electromagnetic shielding gasket 5 is formed such that its short direction substantially coincides with the width direction X, and its long direction substantially coincides with the longitudinal direction Y.

[0089] As shown in Figure 11, the electromagnetic shielding gasket 5 using such expanded metal is formed in a strip shape that is long in the longitudinal direction Y with a predetermined width D by bending a pair of end portions (not shown) of an expanded metal that is wider than a predetermined width D and is roughly rectangular in plan view toward the other end portion (not shown) and overlapping it with the central portion (not shown).

[0090] As a result, the electromagnetic shield gasket 5 consists of a first contact portion 51 that contacts the mating surface 21a of the housing body 21, two second contact portions 52 that contact the mating surface 22a of the lid 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 shielding gasket 5, with the configuration described above, can suppress variations in the contact state with the housing body 21 and the lid 22, similar to Example 1, and ensure stable shielding performance.

[0092] Furthermore, because the expanded metal is formed such that its longitudinal direction and longitudinal direction Y are approximately coincident, the electromagnetic shielding gasket 5 can suppress the deformation of the mesh due to tensile load in the longitudinal direction Y compared to the case where the short direction and longitudinal direction Y are approximately coincident.

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

[0094] Alternatively, when the electromagnetic shielding gasket 5 is formed in a corrugated shape that is continuous in the longitudinal direction Y, for example, it is possible to prevent the bond 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 sheet is formed into a corrugated shape, thereby improving shielding performance.

[0095] In the correspondence between the structure of this invention and the embodiments described above, The first component of this invention corresponds to the housing body 21 of the embodiment, The same applies to the following: The second component 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 22. The distance between the centers in the eye direction corresponds to the distance between the centers in the short eye direction SW, This invention is not limited to the configuration of the embodiments described above, and many other embodiments can be obtained.

[0096] For example, in the above embodiment, the electronic device 1 was described as being mounted on a vehicle such as an automobile, but it is not limited to this, and may be an electronic device mounted on any suitable device. Furthermore, although the housing 2 is described as being roughly rectangular in plan view, it is not limited to this, and the shape of the housing 2 may be any appropriate shape.

[0097] Furthermore, although the housing 2 is composed of a roughly box-shaped housing body 21 with an open top and a lid 22 that covers the opening of the housing body 21, it is not limited to this configuration, and the housing may also be composed of a roughly box-shaped lower housing with an open top and a roughly box-shaped upper housing with an open bottom.

[0098] Furthermore, although the expanded metal constituting the electromagnetic shielding gaskets 3 and 5 is made of stainless steel (more specifically SUS316), it is not limited to this, and any suitable material with conductivity may be used. Although not mentioned in the embodiments described above, 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 expanded metal that has not undergone any surface treatment.

[0099] Furthermore, while we used expanded metal with a plate thickness T of 0.1 mm, this is merely an example and not limited to this; the plate thickness T may be any appropriate thickness. Furthermore, although the expanded metal described has roughly rhomboid-shaped openings, it is not limited to this, and for example, expanded metal with tortoise-shell-shaped openings may also be used. Furthermore, while a roughly diamond-shaped opening was formed by cutting and expanding a thin sheet of material, the method is not limited to this; a roughly diamond-shaped opening may also be formed by drawing and expanding a thin sheet of material while cutting it.

[0100] Furthermore, while the expanded metal used in this example 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 a notch width W of 0.16 ± 0.03 mm, this is merely an example and not limited to this configuration. The center-to-center distance SW in the short direction, the center-to-center distance LW in the long direction, and the notch width W may be configured as appropriate. However, the distance between the centers in the direction of the eye along the longitudinal direction Y is preferably less than half the pitch P in the corrugated shape in order to ensure contact between the mating surface 21a of the housing body 21 and the mating surface 22a of the lid 22.

[0101] Furthermore, while in Example 1 the electromagnetic shielding gasket 3 was configured such that the short direction of the expanded metal substantially coincides with the longitudinal direction Y, and in Example 2 the electromagnetic shielding gasket 5 was configured such that the long direction of the expanded metal substantially coincides with the longitudinal direction Y, the design is not limited to these configurations. For example, an electromagnetic shielding gasket may be configured such that both the short and long directions of the expanded metal intersect the longitudinal direction Y.

[0102] Furthermore, while a waveform shape with a pitch P of 5 mm and a height H of 3 mm was used, this is merely an example and is not limited to this; a waveform shape formed with an appropriate pitch P and height H may also be used. Furthermore, the cross-sectional shape of the electromagnetic shielding gaskets 3 and 5 in the longitudinal section along the longitudinal direction Y is not limited to the above-described embodiment, as long as it is a corrugated shape continuous with respect to the longitudinal direction Y.

[0103] For example, as shown in Figure 12(a), which illustrates 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 corrugated shape with wide spacing between the upwardly protruding peaks and substantially flat valleys. Alternatively, the cross-sectional shape of the electromagnetic shielding gasket 3 in the longitudinal section along the longitudinal direction Y may be a corrugated shape with alternatingly different peak heights, as shown in Figure 12(b).

[0104] Furthermore, while the corrugated shape of the electromagnetic shielding gaskets 3 and 5 is shown as having ridges extending from one side in the width direction X to the other side that are approximately perpendicular to the longitudinal direction Y in a plan view, the design is not limited to this. For example, as shown in Figure 13(a) showing an external perspective view of the electromagnetic shielding gasket 6 and Figure 13(b) showing a plan view of the electromagnetic shielding gasket 6, the electromagnetic shielding gasket 6 may have a corrugated shape in which ridges extending from one side in the width direction X to the other side intersect the longitudinal direction Y in a plan view. In Figure 13(b), the thin lines are shown as lines indicating the boundaries of the arc portions in the corrugated shape, in order to clarify the direction of the edges of the electromagnetic shielding gasket 6 in a plan view.

[0105] In this case, when punching out a flat sheet of expanded metal with a predetermined die, the long direction Y of the electromagnetic shielding gasket 6 is punched out so that it intersects with the long direction of the flat sheet of expanded metal, thereby forming the unfolded electromagnetic shielding gasket 6.

[0106] Furthermore, although electromagnetic shielding gaskets 3 and 5 are shown as having a corrugated shape continuous in the longitudinal direction Y, the design is not limited to this, and electromagnetic shielding gaskets with a corrugated shape continuous in both the width direction X and the longitudinal direction Y may also be used. Specifically, as shown in Figure 13(c), the electromagnetic shielding gasket 7 may be formed such that the first contact portion 71 and the second contact portion 72 are integrally formed in a corrugated shape that is continuous in the width direction X in a longitudinal cross-section along the width direction X.

[0107] This electromagnetic shielding gasket 7 is formed by overlapping a pair of end portions of expanded metal in the central portion, creating a continuous corrugated shape in the width direction X by corrugation processing, and then creating a continuous corrugated shape in the longitudinal direction Y by corrugation processing. Furthermore, the waveform shape continuous in the width direction X shall have a smaller pitch and lower height than the waveform shape continuous in the longitudinal direction Y.

[0108] Furthermore, although the configuration described involves overlapping two second contact portions 32, which are narrower than the first contact portion 31, with the first contact portion 31 having a predetermined width D, the configuration is not limited to this, and a configuration in which the first contact portion 31 and the second contact portions 32, which have approximately the same length in the width direction X, are overlapped is also possible.

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

[0110] Alternatively, an expanded metal, in its unfolded state, has 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. This expanded metal is then folded in a triple-fold manner, as shown in Figure 14(b), to form an electromagnetic shielding gasket 3B.

[0111] Alternatively, an expanded metal, in its unfolded state, has a non-contact portion 37 that does not contact the housing 2 and a second contact portion 38 of a predetermined width D provided in this order on one side of the width direction X of the first contact portion 31, and an electromagnetic shielding gasket 3C may be formed by folding the expanded metal in three outward folds (also called Z-fold, bellows fold, or zigzag fold) so that the second contact portion 38 overlaps the first contact portion 31 with the non-contact portion 37 in between.

[0112] Furthermore, although the electromagnetic shielding gasket 3 is described as a long, rectangular strip in the longitudinal direction Y, it is not limited to this, and any electromagnetic shielding gasket that can be molded into a corrugated shape along the longitudinal direction Y may be used, for example, an electromagnetic shielding gasket that is roughly L-shaped in plan view. Alternatively, as shown in Figure 15, which illustrates an electromagnetic shielding gasket in another embodiment, the electromagnetic shielding gasket 8 may be a substantially annular shape in plan view, along the mating surfaces 21a and 22a of the housing 2.

[0113] In the case of an electromagnetic shielding gasket 8 that is roughly L-shaped in plan view or roughly annular in plan view, as shown in Figure 15, the ridges extending from one side to the other in the direction along the width of the mating surfaces 21a and 22a are formed in a wave shape that intersects in plan view with a direction that is roughly perpendicular to the width of the mating surfaces 21a and 22a in plan view. In other words, in the case of an electromagnetic shielding gasket 8 that is roughly L-shaped in plan view or roughly annular in plan view, the ridges extending from one side to the other in the width direction X are formed in a corrugated shape that intersects with the longitudinal direction Y in plan view.

[0114] Furthermore, after a bending process in which a thin expanded metal sheet with a thickness T wider than a predetermined width D is bent back to form the first contact portion 31 and the second contact portion 32, a corrugation process is performed in which the overlapping first contact portion 31 and the second contact portion 32 are integrally corrugated to form a corrugated shape continuous in the longitudinal direction Y, but the method is not limited to this.

[0115] For example, after a corrugation process in which a thin expanded metal sheet with a thickness T wider than a predetermined width D is corrugated to form a continuous corrugated shape in the longitudinal direction Y, a bending process may be performed in which the corrugated expanded metal is bent back to the 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 an expanded metal that is wider than a predetermined width D and has a roughly rectangular shape in plan view, a bent portion 33 is formed, making it less likely to snag on other electromagnetic shielding gaskets 3, 5 or the worker's clothing, but this is not limited to this.

[0117] For example, as shown in Figure 16(a), which illustrates an electromagnetic shielding gasket in another embodiment, the ends of the electromagnetic shielding gasket 9A in the width direction X may be curved by curling to make it less likely to snag on other electromagnetic shielding gaskets or the worker's clothing. Alternatively, as shown in Figure 16(b), beads 91 extending in the longitudinal direction Y may be formed at both ends in the width direction of the electromagnetic shielding gasket 9B to make it less likely to snag on other electromagnetic shielding gaskets or the worker's clothing. [Explanation of Symbols]

[0118] 2…Cabinet 3, 3A, 3B, 3C, 5, 6, 7, 8, 9A, 9B… Electromagnetic shielding gasket 4…Expanded metal 21…Main unit 21a... mating surface 22... Lid 22a... mating surface 31,51,71...1st contact part 32,34,35,38,52,72…Second contact part 41... Strip-shaped section 42a…Width direction edge D...Predetermined width SW... Distance between centers in the shorter direction X…Width direction Y...longitudinal direction

Claims

1. An electromagnetic shielding gasket interposed at the mating surface between a first member and a second member constituting a conductive housing, A first contact portion that contacts one of the mating surfaces, A second contact portion is provided which 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 aforementioned widthwise length is wider than a desired predetermined width, and the thin expanded metal is bent back to the predetermined width, and the resulting shape is a corrugated shape that is continuous in the longitudinal direction perpendicular to the widthwise direction in a plan view. Electromagnetic shielding gasket.

2. The second contact portion is, The length in the width direction is formed to be less than or equal to half of the predetermined width, and in the unfolded state when laid flat, the first contact portion is provided on both sides in the width direction. The electromagnetic shielding gasket according to claim 1.

3. The expanded metal is formed such that its short direction and its long direction are substantially the same. The electromagnetic shielding gasket according to claim 1.

4. The expanded metal is formed such that its longitudinal direction and its longitudinal direction are substantially the same. The electromagnetic shielding gasket according to claim 1.

5. The distance between the centers of the grain direction of the expanded metal along the longitudinal direction is less than half the pitch distance in the corrugated shape. The electromagnetic shielding gasket according to claim 1.

6. A method for manufacturing an electromagnetic shielding gasket interposed at the mating surface between a first member and a second member constituting a conductive housing, The direction along the width of the mating surface is defined as the width direction. A bending step involves bending a thin expanded metal sheet, whose width is wider than a desired predetermined width, back to 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. The process involves corrugating the superimposed first and second contact portions together to form a continuous wave shape in the longitudinal direction that is perpendicular to the width direction in a plan view. A method for manufacturing electromagnetic shielding gaskets.

7. A punching process in which a thin sheet of expanded metal is punched out with a predetermined die to form a shape in which multiple 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 the longitudinal ends of the multiple strip-shaped portions are connected by width-direction edges that extend in the width direction, The bending step involves bending the strip-shaped portion back to the predetermined width to form the first contact portion and the second contact portion, The corrugation step involves corrugating the expanded metal, which has a plurality of strip-shaped portions bent back to a predetermined width, to form a corrugated shape that is continuous in the longitudinal direction, The process involves bending the strip back to a predetermined width and cutting the strip-shaped portion formed in the corrugated shape from the widthwise edge. A method for manufacturing an electromagnetic shielding gasket according to claim 6.

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