Screw fastening structure using flange cover and flange cover for screw member

Abstract

To provide a screw fastening structure using a flange cover which implements prevention of galvanic corrosion in a fastening structure for a screw with high versatility.SOLUTION: A screw fastening structure (TK) using a flange cover comprises: a conductive screw member (2); a flange cover (1) mounted at a peripheral edge of a flange (22) or a head (21) of the screw member; a substrate (4) including a first through hole (4b) that a shank (23) of the screw member can pass; a conductive plate (3) including a second through hole (31a), that the shank can pass, electrically connected to a wiring pattern (4c) and disposed on the side of a first face (4e) of the substrate; and a female screw member (5) disposed on the side of a second face (4f) of the substrate. In a screw fastened state where the screw member to which the flange cover is mounted is passed through the second through hole and the first through hole and threaded to the female screw member (5), the flange or the head of the screw member is in contact with the plate in a contact portion, and the flange cover is adhered to the substrate or the plate while enclosing the contact portion.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present invention relates to a screw fastening structure using a flange cover and a flange cover for a screw member. [Background technology]

[0002] In a conductive fastening structure in which multiple parts are fastened together while electrical continuity is achieved by screws, it is known that when the screws and the fastened parts are made of dissimilar metals, galvanic corrosion may occur in the presence of an electrolyte such as water. Patent Document 1 describes a technology that prevents this galvanic corrosion.

[0003] The technology described in Patent Document 1 uses a non-conductive sealing member to seal contacting dissimilar metal members from the electrolyte, thereby preventing the occurrence of galvanic corrosion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2021-532310 Summary of the Invention [Problem to be solved by the invention]

[0005] The sealing member in the technology described in Patent Document 1 is a dedicated part that is individually tailored to the arrangement of the screws and the shape of the surrounding parts. Therefore, there is a need for a technology that can suppress the occurrence of galvanic corrosion with as much versatility as possible in screw fastening structures that provide electrical continuity.

[0006] Therefore, an object of the present invention is to provide a screw fastening structure using a flange cover and a flange cover for a screw member that can prevent galvanic corrosion in a screw fastening structure with high versatility. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, a screw fastening structure using a flange cover and a flange cover of a screw member, which are one aspect of an embodiment of the present invention, have the following configurations. 1) A conductive screw member having a protrusion on its bearing surface; a flange cover fitted to a peripheral edge of a flange portion or a head portion of the screw member; a substrate having a conductive portion formed on a first surface and a first through hole through which the shank of the screw member can pass; a female screw member disposed on the second surface side of the substrate, When the screw member to which the flange cover is attached is passed through the first through hole and screwed into the female thread member to form a screw-fastened state, the projection of the screw member and the conductive portion contact each other at a contact portion, The flange cover is sandwiched between the substrate and the seat surface so as to surround the contact portion and be in close contact with the substrate. 2) a conductive screw member; a flange cover fitted to a peripheral edge of a flange portion or a head portion of the screw member; a substrate having a first through hole through which the shank of the screw member can pass; a conductive plate having a second through hole through which the shaft portion can pass, electrically connected to the wiring pattern of the substrate, and attached concentrically to the first through hole on the first surface side of the substrate; a female screw member disposed on the second surface side of the substrate, When the screw member with the flange cover attached is passed through the second through hole and the first through hole in this order and screwed into the female threaded member to be in a screw-fastened state, the flange portion or the head of the screw member comes into contact with the plate at a contact portion, The screw fastening structure uses a flange cover, which is configured to surround the contact portion and adhere closely to the substrate or plate. 3) A flange cover for a screw member, comprising: a circular main body portion having an engaging portion into which the peripheral portion of the head or flange portion of a screw member is fitted; and a flange portion extending radially outward from the entire outer periphery of the main body portion and formed at an angle so as to move away from the main body portion to a first axial side as it extends outward, and which is elastically deformable in the axial direction, wherein the peripheral portion of the screw member is fitted into the engaging portion with the first side facing the shaft portion, and the screw member is passed through a hole formed in a flat plate from one side to be screwed into a female screw member arranged on the other side, and the flange portion is formed so as to be in close contact with the flat plate. [Effects of the Invention]

[0008] The screw fastening structure using the flange cover of the present invention and the flange cover for the screw member have the effect of being able to prevent galvanic corrosion in the screw fastening structure with high versatility. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows a flange cover 1 according to one embodiment of the present invention, where FIG. 1(a) is a plan view from above and FIG. 1(b) is a cross-sectional view at the S1b-S1b position in FIG. 1(a). [Figure 2A] FIG. 2A is an assembly diagram of a screw fastening structure TK using a flange cover 1 according to one embodiment. [Figure 2B] FIG. 2B is a vertical cross-sectional view of the screw fastening structure TK. [Figure 3A] Figure 3A is an assembly diagram showing a screw fastening structure TKA, which is a variant example 1 of the screw fastening structure TK, Figure 3A(a) is an oblique view showing a state in which a flange cover 1 is attached to a screw member 2A used in the screw fastening structure TKA, and Figure 3A(b) is a longitudinal cross-sectional view of the screw fastening structure TKA. [Figure 3B] Figure 3B is an assembly diagram showing a screw fastening structure TKB, which is a variant example 2 of the screw fastening structure TK, Figure 3B(a) is an oblique view showing the state in which a flange cover 1B is attached to a screw member 2B used in the screw fastening structure TKB, and Figure 3B(b) is a longitudinal cross-sectional view of the screw fastening structure TKB. [Figure 4] FIG. 4 is a vertical cross-sectional view showing a screw fastening structure TKC which is a modified example 3 of the screw fastening structure TK. DETAILED DESCRIPTION OF THE INVENTION

[0010] A flange cover 1 for a screw head according to one aspect of an embodiment of the present invention and a screw fastening structure TK using the same will be described with reference to Figures 1, 2A, and 2B. Figure 1 shows a flange cover 1 according to one aspect of an embodiment of the present invention, with Figure 1(a) being a plan view and Figure 1(b) being a cross-sectional view at the S1b-S1b position in Figure 1(a). Figure 2A is an assembly diagram of the screw fastening structure TK using the flange cover 1 according to one aspect. Figure 2B is a longitudinal cross-sectional view of the screw fastening structure TK.

[0011] One embodiment of the screw fastening structure is a structure for screwing together a plurality of conductive members while maintaining electrical continuity via the screw member, and is used for fastening members carrying electronic components inside an electronic device, such as a portable power supply. This fastening structure prevents the occurrence of galvanic corrosion caused by moisture adhering to the conductive fastening portion when rain or beverages unexpectedly enter the inside of the electronic device through a heat exhaust port during indoor or outdoor use.

[0012] As shown in FIG. 2B, the screw fastening structure TK includes a flange cover 1, a screw member 2, a plate 3, a substrate 4, and a stud 5.

[0013] The flange cover 1 is a sealing member made of a non-conductive and elastic material such as silicone rubber. As shown in FIGS. 1(a) and 1(b), the flange cover 1 has a main body 11 and a flange 12. The main body 11 is formed in a thin, annular shape, and has a circular opening 11a centered on its axis CL1. An engagement portion 11b, which is a circumferential groove carved radially outward, is formed in the middle of the opening 11a in the thickness direction. In the main body 11, the wall portion on one side relative to the engagement portion 11b is an outer wall portion 111, and the wall portion on the other side is an inner wall portion 112.

[0014] The flange 12 is formed so as to jut outward from the edge of the inner wall 112 on the outer circumferential surface of the main body 11, overhanging the entire circumference. When viewed from above, the flange 12 has a circular shape centered on the axis CL1. The flange 12 is formed so as to slope in an umbrella shape so as to move away from the main body 11 to the first side in the direction of the axis CL1 as it moves toward the periphery (toward the radial outward direction). The thickness of the flange 12 is thinner than the thickness of the main body 11, allowing it to easily flex and elastically deform in the direction of the axis CL1. The flange 12 may be formed so that its thickness gradually decreases from the main body 11 side toward the periphery, making it more easily flexible in the axial direction.

[0015] The inner diameter φb and height Hb of the engaging portion 11b are set so that it can be fitted into a flange portion 22 of the screw member 2, which will be described next.

[0016] 2A is a flanged pan head machine screw having electrical conductivity, and is a so-called conductive screw having multiple hemispherical protrusions 21a on the bearing surface of the head 21. The protrusions 21a are formed at four locations, for example, at 90° intervals in the circumferential direction. The plate 3 is a conductive metal plate-like member. The plate 3 has an annular base 31 having a through-hole 31a through which the shank 23 of the screw member 2 can pass, and a pair of arms 32 bent in the same direction from the outer periphery of the base 31 and positioned opposite each other in the circumferential direction.

[0017] The substrate 4 is a flat plate member having a through hole 4b formed with approximately the same inner diameter as the through hole 31a, and a pair of arm holes 4a formed at positions equidistant from the center in the radial direction of the through hole 4b. When the through hole 31a of the plate 3 and the through hole 4b of the substrate 4 are arranged in concentric positions, the pair of arms 32 each enter the arm holes 4a, and the base 31 comes into contact with the surface 4e, which is the first surface of the substrate 4. The through hole 4b is also referred to as the first through hole, and the through hole 31a is also referred to as the second through hole.

[0018] A wiring pattern 4c is formed on the back surface 4f, which is the second surface of the substrate 4, and is covered with a resist (not shown). A pair of arm holes 4a are formed in the exposed portions of the wiring pattern 4c that are free of the resist. This allows electrical connection between the wiring pattern 4c and the arm portions 32 of the plate 3 by soldering, as shown in Fig. 2B. Solder fillets 4d are also shown in Fig. 2B. A panel 6 is disposed on the rear surface 4f of the substrate 4 at a predetermined distance from the substrate 4. A stud 5, which is a conductive female screw member having a female screw portion 5a formed thereon, is disposed between the substrate 4 and the panel 6 at a position concentric with the through hole 4b of the substrate 4.

[0019] 2A and 2B, the flange cover 1 is attached by fitting the flange portion 22 of the screw member 2 into the engagement portion 11b while elastically deforming the flange cover 1. At this time, the flange cover 1 is oriented so that the collar portion 12 faces the shank portion 23 of the screw member 2. With the flange cover 1 attached to the flange portion 22, the outer wall portion 111 covers the peripheral edge of the head side of the flange portion 22, and the inner wall portion 112 covers the peripheral edge of the seat surface of the flange portion 22. Hereinafter, the assembly member in which the flange cover 1 is attached to the screw member 2 will be referred to as a covered screw M.

[0020] The covered screw M is passed through the through hole 31a of the plate 3, which is the second through hole, and through the through hole 4b of the substrate 4, which is the first through hole, in that order from the front surface 4e, which is one surface (first surface side) of the substrate 4, and is screwed into the female thread portion 5a of the stud 5 (see arrow DR2 in FIG. 2A). The state in which the screw member 2 is screwed into the female thread portion 5a of the stud 5 arranged on the other surface (second surface side) of the substrate 4 with a predetermined torque and fastened is hereinafter referred to as the screw-fastened state.

[0021] In the screw fastening structure TK, as shown in Fig. 2B, the protrusion 21a of the covered screw M is in rubbing contact with the surface of the base 31 of the plate 3, which is a conductive portion. This ensures mutual conduction among the wiring pattern 4c, the solder fillet 4d, the plate 3, the screw member 2, and the stud 5. In the screw fastening state, the axes of the through hole 31a of the plate 3 and the through hole 4b of the substrate 4 generally coincide and are shown as axis CL. The axis CL1 of the flange cover 1 also generally coincides with axis CL.

[0022] The screw fastening structure TK has dimensions set in the direction of the axis CL so that, in a screw-fastened state, the flange 12 of the flange cover 1 elastically deforms and abuts against the surface 4e of the substrate 4. That is, the flange 12 closely contacts the surface 4e, with the peripheral edge of the flange 12 pressing against the surface 4e with a force F1, which is an elastic repulsive force. Therefore, liquid is prevented from entering the space V surrounded by the flange 12, the surface 4e of the substrate 4, and the plate 3 in FIG. 2B from the surface 4e side of the substrate 4. This prevents galvanic corrosion from occurring at the contact site between the protrusion 21a and the base 31 of the plate 3, even if the plate 3 and the screw member 2 are made of dissimilar metals.

[0023] As described above, the flange portion 12 of the screw fastening structure TK prevents liquid from entering the space V from the surface 4e side. Furthermore, when the thickness ta (see FIG. 1(b)) of the inner wall portion 112 of the flange cover 1 is equal to or greater than the protrusion height tb (see FIG. 2B) of the protrusion 21a, the inner wall portion 112 is sandwiched between the flange portion 22 and the base portion 31 of the plate 3 in the screw fastened state, forming a somewhat crushed, sealed state. Therefore, the inner wall portion 112 prevents liquid from entering the space V1 enclosed by the end face of the inner wall portion 112, the base portion 31, and the seating surface of the flange portion 22. Thus, the formation of two seals further effectively prevents galvanic corrosion at the contact points between the protrusions 21a and the base portion 31 of the plate 3.

[0024] The embodiments of the present invention are not limited to the above-described configurations, and modifications may be made without departing from the spirit of the present invention.

[0025] (Variation 1) 3A(a) and (b), the screw fastening structure TK may be a screw fastening structure TKA that uses a screw member 2A that is a general flanged pan head screw without a protrusion 21a as the screw member 2. In the screw fastening structure TKA, the bearing surface of the flange portion 22 of the screw member 2A directly contacts the base portion 31 of the plate 3, which is a conductive portion, to achieve electrical conduction. At this time, the inner diameter φc (see FIG. 1(b)) of the inner wall portion 112 of the flange cover 1 is made larger than the distance L32, which is the outer dimension of the pair of arm portions 32 of the plate 3, so that the inner wall portion 112 is not sandwiched between the flange portion 22 and the base portion 31.

[0026] 3A(b), liquid is prevented from entering the internal space VA surrounded by the flange 12, the base plate 4, the plate 3, etc. from outside the flange 12. Therefore, even if the plate 3 and the screw member 2A are made of dissimilar metals, the occurrence of galvanic corrosion at the contact area between the flange 22 and the base 31 of the plate 3 is prevented.

[0027] (Variation 2) As shown in Figures 3B(a) and (b), the screw fastening structure TK may be a screw fastening structure TKB that uses a screw member 2B that is a truss screw instead of a flanged pan head screw as the screw member 2. Figures 3B(a) and (b) show a case where the screw member 2 has a protrusion 21a as a conductive screw, but it may not have a protrusion 21a as in the screw fastening structure TKA. The screw member 2B has a truss-shaped head and does not have a flange portion 22. Therefore, the flange cover 1 is a flange cover 1B that can be fitted onto the truss head. In other words, the flange cover 1B is fitted onto the peripheral edge of the head of the screw member 2B to form a covered screw M.

[0028] In the screw fastening structure TKB, when fastened by the screws, the protrusion 21a on the seating surface of the screw member 2B contacts the base 31 of the plate 3, which is a conductive portion, to establish electrical continuity. The dimensions along the axis CL are set so that, when fastened by the screws, the flange 12 of the flange cover 1B elastically deforms and abuts against the surface 4e of the substrate 4. That is, the flange 12 is in intimate contact with the first surface, the peripheral edge of the flange 12, by a force F1, which is an elastic repulsive force. Therefore, liquid is prevented from entering the space VB enclosed by the flange 12, the surface 4e of the substrate 4, and the plate 3 from the surface 4e side of the substrate 4, as shown in FIG. 2B. This prevents galvanic corrosion at the contact point between the protrusion 21a and the base 31 of the plate 3, even if the plate 3 and the screw member 2B are made of dissimilar metals.

[0029] (Variation 3) The screw fastening structures TK, TKA, and TKB described above include a plate 3, but a screw fastening structure TKC may be used in which fastening is performed using a screw member 2 or a screw member 2B having a protrusion 21a without using a plate 3. Fig. 4 shows an example in which a screw member 2B, which is a truss screw having a protrusion 21a on its bearing surface, is used. A wiring pattern 4c1 that is not covered with resist is formed on the front surface 4e of the substrate 4, and when the screw member 2B is screwed into a stud 5, which is a female-threaded member, arranged on the back surface 4f of the substrate 4, in a screw-fastened state, the protrusion 21a comes into contact with the wiring pattern 4c1, which is a conductive portion, and electrical continuity is obtained.

[0030] In the screw fastening structure TKC shown in Figure 4, instead of the flange cover 1 having a flange 12, a flange cover 1C having a body 11 that engages with the head of a truss screw without a flange 12 is used. The thickness of the inner wall 112 of the body 11 is formed slightly larger than the protruding height of the protrusion 21a, so that in the screw-fastened state, the inner wall 112 is sandwiched and tightly attached between the substrate 4 and the bearing surface having the protrusion 21a, regardless of the presence or absence of the wiring pattern 4c1. Therefore, external electrolyte liquids such as water cannot enter the space VC inside the inner wall 112. This prevents the occurrence of galvanic corrosion at the contact point between the protrusion 21a and the wiring pattern 4c1.

[0031] The above-described embodiment and Modifications 1 and 2 may be combined as freely as possible. The screw member 2 is not limited to the above-described pan head machine screw and truss machine screw. The head and drive portion may also be a cross recess or a hexagonal recess. The protrusion 21a provided on the screw member 2 side may also be provided on the substrate 4 side.

[0032] The stud 5 is not limited to a columnar stud, but may be any conductive female screw member having a female thread portion into which the screw members 2, 2A, 2B can be threaded. In the screw fastening structures TK, TKA, TKB, it is sufficient that electrical continuity is obtained between the wiring pattern 4c of the substrate 4 and the stud 5, which is a female screw member.

[0033] As described above in detail, the screw fastening structures TK, TKA, and TKB can be used by forming a flange cover that matches the head shape of the screw member, and simply adjusting the dimensions to fit the fastening structure using that type of screw. Therefore, it is possible to prevent galvanic corrosion in screw fastening structures with high versatility. [Explanation of symbols]

[0034] 1,1B Flange cover (sealing material) 11 Main body 11a opening 11b Engagement part 111 Exterior wall 112 Inner wall 12 Tsuba section 2, 2A, 2B screw members 21 Head 21a protrusion 22 Flange 23 Shaft 3 plates 31 Base 31a Through hole 32 Arm 4 boards 4a arm hole 4b Through hole 4c,4c1 wiring pattern 4d solder fillet 4e surface 4F back side 5 studs 5a Female thread 6 Panels CL,CL1 axis line F1 force Hb height L32 distance M Covered screw TK, TKA, TKB, TKC screw fastening structure ta Thickness tb protrusion height V,V1,VA,VB,VC space φb,φc inner diameter

Claims

1. a conductive screw member having a protrusion on a seat surface; a flange cover fitted to a peripheral edge of a flange portion or a head portion of the screw member; a substrate having a conductive portion formed on a first surface and a first through hole through which the shank of the screw member can pass; a female screw member disposed on the second surface side of the substrate, When the screw member to which the flange cover is attached is passed through the first through hole and screwed into the female thread member to form a screw-fastened state, the projection of the screw member and the conductive portion contact each other at a contact portion, A screw fastening structure using a flange cover, in which the flange cover is sandwiched between the substrate and the seat surface so as to surround the contact portion and be in close contact with it.

2. a conductive screw member; a flange cover fitted to a peripheral edge of a flange portion or a head portion of the screw member; a substrate having a first through hole through which the shank of the screw member can pass; a conductive plate having a second through hole through which the shaft portion can pass, electrically connected to the wiring pattern of the substrate, and attached concentrically to the first through hole on the first surface side of the substrate; a female screw member disposed on the second surface side of the substrate, When the screw member with the flange cover attached is passed through the second through hole and the first through hole in this order and screwed into the female threaded member to be in a screw-fastened state, the flange portion or the head of the screw member comes into contact with the plate at a contact portion, A screw fastening structure using a flange cover, wherein the flange cover is configured to surround the contact portion and adhere closely to the substrate or the plate.

3. 3. A screw fastening structure using a flange cover according to claim 2, wherein the screw member has the flange portion and a plurality of protrusions on a seat surface of the flange portion, and the protrusions come into contact with the plate at the contact portion.

4. the flange cover has an annular main body portion into which the screw member is fitted, and a flange portion that protrudes radially outward from a periphery of the main body portion and is elastically deformable, In the screw fastened state, 3. A screw fastening structure using a flange cover according to claim 2, wherein the flange portion elastically deforms in the axial direction to surround the contact portion and come into close contact with the substrate.

5. the flange cover has an annular main body portion into which the screw member is fitted, In the screw fastened state, 3. The screw fastening structure using a flange cover according to claim 2, wherein the body portion is sandwiched between the head portion and the plate so as to surround the contact portion.

6. a ring-shaped main body portion having an engagement portion into which a peripheral edge portion of a head portion or a flange portion of a screw member is fitted; a flange portion extending radially outward from the entire outer periphery of the main body portion, inclined outwardly so as to be spaced apart from the main body portion toward a first side in the axial direction, and elastically deformable in the axial direction; Equipped with A flange cover for a screw member, which is formed so that when the peripheral portion of the screw member is fitted into the engaging portion with the first side facing the shaft portion, and the screw member is passed through a hole formed in a flat plate from one side and screwed into a female screw member arranged on the other side, the flange portion is in close contact with the flat plate.

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