Bolted fastening structure for conductive member

Abstract

To provide a bolted fastening structure for a conductive member that can reduce the fastening force applied to the conductive member and easily destroy an oxide film.SOLUTION: In a bolted fastening structure for a conductive member according to the present invention, a convex portion 13 is provided on an inner surface 11 of a first conductive member 1, which corresponds to the connecting surface with a second conductive member 2, and a concave portion 23 is provided on an inner surface 21 of the second conductive member 2, which corresponds to the connecting surface with the first conductive member 1. This reduces the rigidity of the second conductive member 2, in which the concave portion 23 is provided, and the convex portion 13 of the first conductive member 1 can destroy the oxide film formed in the concave portion 23 of the second conductive member 2 with a relatively small fastening force.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a bolt fastening structure for a conductive member such as a bus bar. [Background technology]

[0002] As a conventional bolt fastening structure for a conductive member, for example, the structure described in the following patent document is known.

[0003] 12 , for example, in a conventional bolt fastening structure for conductive members, when a first conductive member 1 and a second conductive member 2 made of aluminum, a conductive metal material, are fastened together with a bolt 3 and a nut 4, the first conductive member 1 has an inner surface 11 that faces the second conductive member 2 and is provided with irregularities. That is, the inner surface 11 of the first conductive member 1 is provided with a plurality of protrusions 13 that protrude toward the inner surface 11. As a result, the fastening force of the bolt 3 and the nut 4 causes the protrusions 13 to plastically deform, destroying an oxide film formed on the surface of the aluminum that constitutes the first conductive member 1, thereby reducing the contact resistance between the first conductive member 1 and the second conductive member 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7402422 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional bolt fastening structure of conductive members, the convex portion 13 is provided only on one side, the first conductive member 1. Therefore, when the oxide film is broken, a relatively large fastening force needs to be applied to the first conductive member 1 and the second conductive member 2, and there is still room for improvement.

[0006] The present invention was devised with an eye on these technical problems, and aims to provide a bolt fastening structure for conductive members that can reduce the fastening force applied to the conductive members and easily destroy the oxide coating. [Means for solving the problem]

[0007] In one aspect, the present invention provides a bolt fastening structure for conductive members in which a first conductive member and a second conductive member, each formed from a conductive metal material, are fastened together with a bolt and a nut, wherein the first conductive member has a convex portion on a side surface that overlaps with the second conductive member, and the second conductive member has a concave portion on a side surface that overlaps with the first conductive member that can engage with the convex portion. [Effects of the Invention]

[0008] According to the present invention, a convex portion is provided on the surface of the first conductive member that connects with the second conductive member, and a concave portion is provided on the surface of the second conductive member that connects with the first conductive member. This reduces the rigidity of the second conductive member that has the concave portion, and allows the convex portion of the first conductive member to destroy the oxide film formed in the concave portion of the second conductive member with a relatively small fastening force. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a bolt fastening structure for a conductive member according to the present invention; [Figure 2] 1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a plan view of the inner surface of a first conductive member, and FIG. 1B is a plan view of the inner surface of a second conductive member. [Figure 3] 2A and 2B are views corresponding to a cross section taken along line XX in FIG. 1 showing the first embodiment of the present invention, in which (a) shows the state before bolt tightening and (b) shows the state after bolt tightening. [Figure 4] 1A and 1B show a first modified example of the first embodiment of the present invention, in which FIG. 1A is a plan view of the inner surface of a first conductive member, and FIG. 1B is a plan view of the inner surface of a second conductive member. [Figure 5]2A and 2B are views corresponding to a cross section taken along line XX in FIG. 1, illustrating a first modified example of the first embodiment of the present invention, in which (a) shows a state before bolt tightening and (b) shows a state after bolt tightening. [Figure 6] 5A and 5B show a second modified example of the first embodiment of the present invention, in which (a) is a plan view of the inner surface of the first conductive member, and (b) is a plan view of the inner surface of the second conductive member. [Figure 7] 2A and 2B are views corresponding to a cross section taken along line XX in FIG. 1, illustrating a second modified example of the first embodiment of the present invention, in which (a) shows a state before bolt tightening and (b) shows a state after bolt tightening. [Figure 8] 5A and 5B show a second embodiment of the present invention, in which FIG. 5A is a plan view of the inner surface of a first conductive member, and FIG. 5B is a plan view of the inner surface of a second conductive member. [Figure 9] 2A and 2B are views corresponding to a cross section taken along line XX in FIG. 1 showing a second embodiment of the present invention, in which (a) shows the state before bolt tightening and (b) shows the state after bolt tightening. [Figure 10] 10A and 10B show a modification of the second embodiment of the present invention, in which (a) is a plan view of the inner surface of a first conductive member, and (b) is a plan view of the inner surface of a second conductive member. [Figure 11] 10A and 10B are views showing a modified example of the second embodiment of the present invention, corresponding to a cross section taken along line XX in FIG. 1, in which (a) shows the state before bolt tightening and (b) shows the state after bolt tightening. [Figure 12] FIG. 10 is a cross-sectional view showing a conventional bolt fastening structure for a conductive member. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a bolt fastening structure for a conductive member according to the present invention will be described in detail with reference to the drawings. Note that the following embodiment shows an example in which the bolt fastening structure for a conductive member according to the present invention is applied to a bolt fastening structure for a bus bar, similar to the conventional example.

[0011] (Bolt fastening structure for conductive members) FIG. 1 is a perspective view showing a bolt fastening structure for a conductive member according to the present invention.

[0012] 1, for example, a bolt fastening structure according to the present invention includes a first conductive member 1 and a second conductive member 2, each formed from a conductive metal material, fastened together by a bolt 3 and a nut 4, which are fastening members. Here, the conductive metal material forming the first conductive member 1 and the second conductive member 2 may be, for example, copper, a copper alloy, aluminum, or an aluminum alloy, and can be arbitrarily changed depending on the specifications of each conductive member. Alternatively, a configuration may be adopted in which different conductive metal materials are combined, such as forming the first conductive member 1 from copper or a copper alloy and the second conductive member 2 from aluminum or an aluminum alloy.

[0013] Furthermore, it is desirable that the first conductive member 1 and the second conductive member 2 are subjected to a surface treatment. This can improve the durability of the first conductive member 1 and the second conductive member 2. Examples of surface treatments that can be applied to the first conductive member 1 and the second conductive member 2 include Ag plating, Sn plating, Ni plating, and alloy plating thereof (Ag alloy plating, Sn alloy plating, Ni alloy plating). Among these, Ag plating, Ag alloy plating, Sn plating, and Sn alloy plating are particularly desirable. In this case, for example, Ni plating, Ni alloy plating, or Cu plating may be applied as a base. Furthermore, when the first conductive member 1 and the second conductive member 2 are made of aluminum or an aluminum alloy, it is desirable to perform a zincate treatment or a double zincate treatment before the surface treatment in order to suppress the formation of an oxide film.

[0014] [First embodiment] Fig. 2 shows a bolt fastening structure for conductive members according to a first embodiment of the present invention, where (a) is a plan view of the inner surface of a first conductive member and (b) is a plan view of the inner surface of a second conductive member. Fig. 3 is a cross-sectional view taken along line XX in Fig. 1 showing the first embodiment of the present invention, where (a) shows the state before bolt fastening and (b) shows the state after bolt fastening.

[0015] 2 and 3, the first conductive member 1 is formed in the shape of a rectangular plate having an inner surface 11 and an outer surface 12 that are generally parallel. A first bolt insertion hole 10, into which a shank 32 of a bolt 3 can be inserted, is formed in the first conductive member 1 in a through-hole shape along the plate thickness direction at the portion of the first conductive member 1 where the first conductive member 1 is fastened to the second conductive member 2. The first bolt insertion hole 10 has an inner diameter that is smaller than the outer diameter of the flange portion 33 of the bolt 3 and slightly larger than the shank 32 of the bolt 3. As a result, the first conductive member 1 is connected to the second conductive member 2 in a state where it is pressed toward the second conductive member 2 by the fastening force of the bolt 3 and the nut 4.

[0016] Furthermore, the first conductive member 1 has, on its inner surface 11, which faces and is connected to the second conductive member 2, a plurality of protrusions 13 that protrude from the outer surface 12 toward the inner surface 11 in an area that is on the outer periphery of the first bolt insertion hole 10 and overlaps with the second conductive member 2. The protrusions 13 are generally pyramidal in shape, with a base end 131 being the widest and gradually decreasing in width toward a tip end 132. More specifically, the base width W1 of the base end 131 of the protrusions 13 is smaller than the opening width W2 of the opening 231 of the recess 23, and the height Tx, which is the amount of protrusion from the inner surface 11, is greater than the depth Dx, which is the amount of recession of the recess 23 of the second conductive member 2, which will be described later. The first conductive member 1 is formed by press molding, as will be described later, and the protrusions 13 are formed to protrude from the outer surface 12 of the first conductive member 1 toward the inner surface 11. The protrusions 13 are not limited to the quadrangular pyramidal protrusions exemplified in this embodiment, as shown in the first and second modified examples described later, for example. The means for forming the protrusions 13 is not limited to the press molding, and any means, such as machining, can be used depending on the specifications of the conductive member to which the protrusions 13 are to be applied.

[0017] Similar to the first conductive member 1, the second conductive member 2 is formed in the shape of a rectangular plate having inner and outer surfaces 21 and 22 that are generally parallel to each other. A second bolt insertion hole 20, into which a shank 32 of a bolt 3 can be inserted, is formed in the second conductive member 2 in the plate thickness direction at the portion of the second conductive member 2 where the second conductive member 2 is fastened to the first conductive member 1. The second bolt insertion hole 20 has an inner diameter that is smaller than the outer diameter of a flange portion 33 of the bolt 3 and slightly larger than the shank 32 of the bolt 3. As a result, the second conductive member 2 is connected to the first conductive member 1 while being pressed toward the first conductive member 1 by the fastening force of the bolt 3 and the nut 4.

[0018] Furthermore, the second conductive member 2 has, on its inner surface 21 connected to face the first conductive member 1, a plurality of recesses 23 recessed from the inner surface 21 toward the outer surface 22 in an area on the outer periphery of the second bolt insertion hole 20 and overlapping with the first conductive member 1, and capable of engaging with the protrusions 13 of the first conductive member 1. The recesses 23 are formed so that an opening 231 is widest and gradually narrows toward a bottom 232. More specifically, the recesses 23 have a generally quadrangular pyramid-shaped space formed therein, and the opening width W2 of the opening 231 is greater than the base width W1 of the base end 131 of the protrusion 13, and the depth Dx, which is the amount of recession from the inner surface 21, is smaller than the height Tx of the protrusion 13 of the first conductive member 1. The second conductive member 2 is formed by press molding as described below, and the recess 23 is formed so as to recess from the inner surface 21 side toward the outer surface 22 side of the second conductive member 2. Note that the recess 23 is not limited to the quadrangular pyramid-shaped recess exemplified in this embodiment, as shown in the first and second modified examples described below, for example. The means for forming the recess 23 is not limited to the press molding, and any means, such as machining, can be used depending on the specifications of the conductive member to which the recess 23 is to be applied.

[0019] The bolt 3 is a well-known flanged bolt made of, for example, steel. That is, the bolt 3 integrally includes a head 31, a shank 32 that is formed with a stepped diameter reduction relative to the head 31 and is inserted into the first bolt insertion hole 10 and the second bolt insertion hole 20, and a flange 33 that is formed with an expanded diameter at the end of the head 31 on the shank 32 side. The nut 4 is a well-known flanged nut made of, for example, steel. That is, the nut 4 integrally includes a nut body 41 and a flange 42 that is formed with an expanded diameter at one axial end of the nut body 41. Note that the bolt 3 and the nut 4 may be made of a material other than the steel, such as stainless steel, copper (including copper alloy), ceramic, or resin.

[0020] With the above-described configuration, as shown in particular in FIG. 3 , when the bolt 3 and nut 4 are fastened, the first conductive member 1 and the second conductive member 2 are electrically connected via the protrusions 13 and the recesses 23, as the tip 132 of the protrusion 13 is pressed against the bottom 232 of the recess 23, destroying the oxide coating (not shown) formed on the protrusions 13 and the recesses 23. Specifically, the sharp tip 132 of the protrusion 13 is pressed against the bottom 232 of the recess 23 by point contact, thereby maximizing the surface pressure of the protrusions 13 against the recesses 23. This promotes plastic deformation of the protrusions 13 and the recesses 23, effectively destroying the oxide coating (not shown) on the protrusions 13 and the recesses 23.

[0021] (Conductive member connection process) First, in the first step (pressing step), the first conductive member 1 and the second conductive member 2, which are formed into plate shapes, are pressed. Specifically, the first bolt insertion holes 10 and the protrusions 13 are formed in the first conductive member 1 by the press working, and the second bolt insertion holes 20 and the recesses 23 are formed in the second conductive member 2 by the press working.

[0022] Subsequently, after the press working of the first step, if the first conductive member 1 and the second conductive member 2 are made of a non-plated material, the first conductive member 1 and the second conductive member 2 are plated in the second step (plating step). Specific plating treatments include the aforementioned Ag plating, Sn plating, Ni plating, or alloy plating thereof (Ag alloy plating, Sn alloy plating, Ni alloy plating). Furthermore, if the first conductive member 1 and the second conductive member 2 are made of aluminum or an aluminum alloy, it is desirable to perform a zincate treatment or double zincate treatment before the plating step in order to suppress the formation of an oxide film. On the other hand, if the first conductive member 1 and the second conductive member 2 are made of a plated material after the press working of the first step, the second step (plating step) is omitted.

[0023] Thereafter, in a third step (assembly step) that is performed after the second step if the first conductive member 1 and the second conductive member 2 are made of an unplated material, or after the first step if the first conductive member 1 and the second conductive member 2 are made of a plated material, a nut 4 is screwed onto the tip of the shank 32 of the bolt 3 that has been inserted so as to pass through the first bolt insertion hole 10 and the second bolt insertion hole 20, with the convex portion 13 engaged with the concave portion 23. As a result, the first conductive member 1 and the second conductive member 2 are fastened together by the bolt 3 and the nut 4, and are electrically connected to each other via the convex portion 13 and the concave portion 23.

[0024] (Effects of this embodiment) As described above, in the bolt fastening structure for conductive members according to this embodiment, convex portions 13 are provided on inner surface 11 of first conductive member 1, which corresponds to the connecting surface with second conductive member 2, and concave portions 23 are provided on inner surface 21 of second conductive member 2, which corresponds to the connecting surface with first conductive member 1. This reduces the rigidity of second conductive member 2, in which concave portions 23 are provided, and it is possible for convex portions 13 of first conductive member 1 to destroy an oxide coating (not shown) formed on concave portions 23 of second conductive member 2 with a relatively small fastening force.

[0025] In this embodiment, the base width W1 of the protrusion 13 is set smaller than the opening width W2 of the recess 23, and the height T1 of the protrusion 13 is set larger than the depth D1 of the recess 23. This makes it possible to reliably bring the tip 132 of the protrusion 13 into contact with the bottom 232 of the recess 23, thereby facilitating destruction of the oxide film of the recess 23 by the protrusion 13.

[0026] In this embodiment, the protrusions 13 are tapered to have a triangular cross section, which increases the surface pressure of the protrusions 13 against the recesses 23, allowing the protrusions 13 to more effectively destroy the oxide coating of the recesses 23.

[0027] In this embodiment, the protrusions 13 and the recesses 23 are formed by press molding, which makes it possible to easily form the protrusions 13 and the recesses 23, thereby improving the productivity of the first conductive member 1 and the second conductive member 2.

[0028] In this embodiment, a plating process is performed as a surface treatment on one or both (both in this embodiment) of the first conductive member 1 and the second conductive member 2. This can improve the durability of the first conductive member and the second conductive member.

[0029] In this embodiment, it is desirable that the surface of each of the first conductive member 1 and the second conductive member 2 be, for example, Ag-plated. This makes it possible to reduce the contact resistance between the convex portion 13 and the concave portion 23, and ensures good electrical conductivity between the first conductive member 1 and the second conductive member 2.

[0030] Furthermore, in this embodiment, it is desirable that, in addition to the above-mentioned Ag plating, for example, Sn plating is applied as the surface treatment of each of the first conductive member 1 and the second conductive member 2. In this way, the Sn plating, which is a relatively soft metal, promotes the elastic deformation of the recesses 23 by the protrusions 13, and the contact area between the protrusions 13 and the recesses 23 can be increased.

[0031] In this embodiment, flanged bolts 3 and nuts 4 are used as fastening members. This allows the fastening force to be applied to the first conductive member 1 and the second conductive member 2 over a wider range, and promotes destruction of the oxide film (not shown) on the recessed portion 23 by the protrusion 13.

[0032] (First Modification) 4 and 5 show a first modified example of the first embodiment of the bolt fastening structure for a conductive member according to the present invention, in which the shape of the convex portion 13 according to the first embodiment is changed. Note that the basic configuration other than this change is the same as that of the first embodiment, and therefore the same components as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0033] Fig. 4 shows a bolt fastening structure for conductive members according to a first modified example of the first embodiment of the present invention, where (a) is a plan view of the inner surface of the first conductive member and (b) is a plan view of the inner surface of the second conductive member. Fig. 5 is a cross-sectional view taken along line XX in Fig. 1 showing the first modified example of the first embodiment of the present invention, where (a) shows the state before bolt fastening and (b) shows the state after bolt fastening.

[0034] For example, as shown in Figures 4 and 5, in the bolt fastening structure of the conductive member according to this modified example, the convex portion 13 of the first conductive member 1 is formed in an elliptical (oval) shape with a cross section extending in the protruding direction, and the base width W1 of the base end portion 131 is smaller than the opening width W2 of the opening 231 of the recess 23, and the height Tx, which is the amount of protrusion from the inner surface 11, is larger than the depth Dx, which is the amount of recession of the recess 23 of the second conductive member 2, which will be described later.

[0035] On the other hand, the recess 23 of the second conductive member 2 has a space formed therein that has a roughly semicircular cross section, and the opening width W2 of the opening 231 is larger than the base width W1 of the base end 131 of the protrusion 13, and the depth Dx, which is the amount of recession from the inner surface 21, is smaller than the height Tx of the protrusion 13 of the first conductive member 1.

[0036] With the above-described configuration, as shown in particular in FIG. 5 , when the bolt 3 and nut 4 are fastened, the first conductive member 1 and the second conductive member 2 are electrically connected via the convex portion 13 and the recess 23 by pressing the tip 132 of the convex portion 13 against the bottom 232 of the recess 23, destroying the oxide films formed on the convex portion 13 and the recess 23. Specifically, the rounded tip 132 of the convex portion 13 is pressed against the curved bottom 232 of the recess 23 by point contact, thereby maximizing the surface pressure of the convex portion 13 against the recess 23. This promotes plastic deformation of the convex portion 13 and the recess 23, effectively destroying the oxide films on the convex portion 13 and the recess 23.

[0037] (Effects of this modified example) As described above, in this modification, convex portion 13 of first conductive member 1 is formed to have an elliptical (oval) cross section extending in the protruding direction, and concave portion 23 of second conductive member 2 is configured to form a space with a semicircular cross section therein. This reduces damage to tip portion 132 of convex portion 13 compared to the first embodiment, in which tip portion 132 is formed to have a relatively sharp triangular cross section, making it easier to handle first conductive member 1. As a result, the workability of fastening first conductive member 1 and second conductive member 2 can be improved.

[0038] (Second Modification) 6 and 7 show a second modified example of the first embodiment of the bolt fastening structure for a conductive member according to the present invention, in which the shape of the convex portion 13 according to the first embodiment is changed. Note that the basic configuration other than this change is the same as that of the first embodiment, and therefore the same components as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0039] Fig. 6 shows a bolt fastening structure for conductive members according to a second modified example of the first embodiment of the present invention, where (a) is a plan view of the inner surface of the first conductive member and (b) is a plan view of the inner surface of the second conductive member. Fig. 7 is a cross-sectional view taken along line XX in Fig. 1 showing the second modified example of the first embodiment of the present invention, where (a) shows the state before bolt fastening and (b) shows the state after bolt fastening.

[0040] For example, as shown in Figures 6 and 7, in the bolt fastening structure of the conductive member according to this modified example, the convex portion 13 of the first conductive member 1 is formed so that its cross section is roughly rectangular, the base width W1 of the base end portion 131 is smaller than the opening width W2 of the opening 231 of the recess 23, and the height Tx, which is the amount of protrusion from the inner surface 11, is relatively larger than the depth Dx, which is the amount of recession of the recess 23 of the second conductive member 2, which will be described later.

[0041] On the other hand, recess 23 of second conductive member 2 has a space formed therein that has a roughly rectangular cross section, and opening width W2 of opening 231 is greater than base width W1 of base end 131 of protrusion 13, and depth Dx, which is the amount of recess from inner surface 21, is smaller than height Tx of protrusion 13 of first conductive member 1. Also, in this modification, recess 23 forms a space with a roughly rectangular cross section, so that bottom 232 of recess 23 is formed flat and roughly parallel to tip 132 of protrusion 13. In other words, in this modification, tip 132 of protrusion 13 and bottom 232 of recess 23 are configured to be in surface contact.

[0042] With the above-described configuration, as shown in particular in FIG. 7 , when the bolt 3 and nut 4 are fastened, the first conductive member 1 and the second conductive member 2 are electrically connected via the convex portion 13 and the recess 23 by pressing the tip 132 of the convex portion 13 against the bottom 232 of the recess 23, destroying the oxide films formed on the convex portion 13 and the recess 23. Specifically, the tip 132 of the convex portion 13, which is formed flat, presses against the flat bottom 232 of the recess 23 through a relatively small area, thereby increasing the surface pressure of the convex portion 13 against the recess 23. This promotes plastic deformation of the convex portion 13 and the recess 23, effectively destroying the oxide films on the convex portion 13 and the recess 23.

[0043] (Effects of this modified example) As described above, in this modification, convex portion 13 of first conductive member 1 is formed so as to have a generally rectangular cross section, and concave portion 23 of second conductive member 2 is configured to form a space having a rectangular cross section therein. This makes it possible to increase the contact area of ​​tip portion 132 of convex portion 13 with bottom portion 232 of concave portion 23, thereby improving the contact reliability and electrical conductivity between first conductive member 1 and second conductive member 2.

[0044] Second Embodiment 8 and 9 show a second embodiment of the bolt fastening structure for a conductive member according to the present invention, in which the configuration of the convex portion 13 according to the first embodiment is modified. Note that the basic configuration other than the above modifications is the same as that of the first embodiment, and therefore the same components as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0045] Fig. 8 shows a bolt fastening structure for conductive members according to a second embodiment of the present invention, where (a) is a plan view of the inner surface of a first conductive member and (b) is a plan view of the inner surface of a second conductive member. Fig. 9 is a cross-sectional view taken along line XX in Fig. 1 showing the second embodiment of the present invention, where (a) shows the state before bolt fastening and (b) shows the state after bolt fastening.

[0046] 8 and 9, in this embodiment, the protrusion 13 provided on the first conductive member 1 has a generally quadrangular pyramid shape, with the base width W1 of the base end 131 being greater than the opening width W2 of the opening 231 of the recess 23, and the height Tx, which is the amount of protrusion from the inner surface 11, being smaller than the depth Dx, which is the amount of recession of the recess 23 in the second conductive member 2. Note that the first conductive member 1 is formed by press molding similar to that in the first embodiment, and the protrusion 13 is formed so as to protrude from the outer surface 12 side of the first conductive member 1 toward the inner surface 11 side. Note that the shape of the protrusion 13 is not limited to the quadrangular pyramid shape exemplified in this embodiment, as will be shown in modified examples described later, for example.

[0047] Meanwhile, recess 23 provided in second conductive member 2 has a generally quadrangular pyramidal space formed therein, and opening width W2 of opening 231 is smaller than base width W1 of base end 131 of protrusion 13, and depth Dx, which is the amount of recess from inner surface 21, is larger than height Tx of protrusion 13 of first conductive member 1. Note that second conductive member 2 is formed by press molding similar to that of the first embodiment, and recess 23 is formed so as to recess from inner surface 21 toward outer surface 22 of second conductive member 2. Note that recess 23 is not limited to the quadrangular pyramidal recess exemplified in this embodiment, as will be shown in modified examples described later, for example.

[0048] With the above-described configuration, as shown in particular in FIG. 9 , when the bolt 3 and nut 4 are fastened, the first conductive member 1 and the second conductive member 2 are electrically connected via the protrusions 13 and the recesses 23, as the base ends 131 of the protrusions 13 are pressed against the openings 231 of the recesses 23, destroying the oxide films (not shown) formed on the protrusions 13 and the recesses 23. Specifically, the base ends 131 of the protrusions 13 are pressed against the openings 231 of the recesses 23 by line contact, and stress acting via the protrusions 13 is concentrated at the openings 231 of the recesses 23. This promotes plastic deformation of the protrusions 13 and the recesses 23, effectively destroying the oxide films (not shown) on the protrusions 13 and the recesses 23.

[0049] (Effects of this embodiment) As described above, in this embodiment, the base width W1 of the protrusion 13 is set larger than the opening width W2 of the recess 23, and the height T1 of the protrusion 13 is set smaller than the depth D1 of the recess 23. Therefore, the base end 131 of the protrusion 13 abuts against the opening 231 of the recess 23, so that the stress acting via the protrusion 13 can be concentrated on the opening 231 of the recess 23. This allows the protrusion 13 to effectively destroy the oxide film of the recess 23.

[0050] (Variation) 10 and 11 show a modified example of the second embodiment of the bolt fastening structure for a conductive member according to the present invention, in which the shape of the convex portion 13 according to the first embodiment is changed. Note that the basic configuration other than these changes is the same as that of the second embodiment, and therefore the same components as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0051] Fig. 10 shows a bolt fastening structure for conductive members according to a modified example of the second embodiment of the present invention, where (a) is a plan view of the inner surface of a first conductive member and (b) is a plan view of the inner surface of a second conductive member. Fig. 11 is a cross-sectional view taken along line XX in Fig. 1 showing a modified example of the second embodiment of the present invention, where (a) shows the state before bolt fastening and (b) shows the state after bolt fastening.

[0052] For example, as shown in Figures 10 and 11, in the bolt fastening structure of the conductive member according to this modified example, the convex portion 13 of the first conductive member 1 has a cross section that is roughly semicircular, the base width W1 of the base end portion 131 is larger than the opening width W2 of the opening 231 of the recess 23, and the height Tx, which is the amount of protrusion from the inner surface 11, is smaller than the depth Dx, which is the amount of recession of the recess 23 of the second conductive member 2.

[0053] On the other hand, the recess 23 of the second conductive member 2 has a space formed therein that has a roughly semicircular cross section, and the opening width W2 of the opening 231 is smaller than the base width W1 of the base end 131 of the protrusion 13, and the depth Dx, which is the amount of recession from the inner surface 21, is greater than the height Tx of the protrusion 13 of the first conductive member 1.

[0054] 11 , when the bolt 3 and the nut 4 are fastened, the first conductive member 1 and the second conductive member 2 are electrically connected via the protrusions 13 and the recesses 23 by pressing the base ends 131 of the protrusions 13 against the openings 231 of the recesses 23, destroying the oxide films (not shown) formed on the protrusions 13 and the recesses 23. Specifically, the curved base ends 131 of the protrusions 13 are pressed against the openings 231 of the recesses 23 by line contact, so that stress acting via the protrusions 13 is concentrated at the openings 231 of the recesses 23. This promotes plastic deformation of the protrusions 13 and the recesses 23, effectively destroying the oxide films (not shown) on the protrusions 13 and the recesses 23.

[0055] (Effects of this modified example) As described above, in this modification, the convex portion 13 of the first conductive member 1 is formed so as to have a generally semicircular cross section, and the concave portion 23 of the second conductive member 2 is configured to form a space with a semicircular cross section therein. This reduces damage to the tip portion 132 of the convex portion 13 compared to the first embodiment, in which the tip portion 132 is formed with a relatively sharp triangular cross section, making it easier to handle the first conductive member 1. As a result, the workability of fastening the first conductive member 1 and the second conductive member 2 can be improved.

[0056] The present invention is not limited to the configurations exemplified in the above-described embodiments, and for example, the specific shapes of the convex portion 13 and the concave portion 23 can be freely changed according to the specifications of the object of application, within the scope of the spirit of the present invention.

[0057] Furthermore, the bolt fastening structure of the conductive member according to the present invention can be applied to various objects, such as wiring materials, terminal blocks, and connectors having a bolt fastening structure, in addition to the bolt-fastened bus bars exemplified in the above embodiments. [Explanation of symbols]

[0058] 1...First conductive member 11...Inner surface 12...Outer surface 13...Convex part 2...Second conductive member 21...Inner surface 22…Outer surface 23...recess 3...Bolt 33...Flange 4...Nut 43...Flange W1...Base width (maximum width) W2...Opening width Tx…Height Dx...depth

Claims

1. A bolt fastening structure for conductive members in which a first conductive member and a second conductive member, each formed of a conductive metal material, are fastened together by a bolt and a nut, the first conductive member has a protrusion on a side surface that overlaps the second conductive member, the second conductive member has a recess that can be engaged with the protrusion on a side surface that overlaps the first conductive member; 1. A bolt fastening structure for a conductive member, comprising:

2. 2. The bolt fastening structure for a conductive member according to claim 1, the maximum width of the convex portion is smaller than the opening width of the concave portion, The height of the convex portion is greater than the depth of the concave portion.

1. A bolt fastening structure for a conductive member, comprising:

3. 2. The bolt fastening structure for a conductive member according to claim 1, The maximum width of the convex portion is larger than the opening width of the concave portion, The height of the convex portion is smaller than the depth of the concave portion.

1. A bolt fastening structure for a conductive member, comprising:

4. 4. The bolt fastening structure for a conductive member according to claim 2 or 3, The convex portion is formed in a tapered shape with a cross section that is generally triangular.

1. A bolt fastening structure for a conductive member, comprising:

5. 4. The bolt fastening structure for a conductive member according to claim 2 or 3, The cross section of the protruding portion is formed in an elliptical shape extending in the protruding direction.

1. A bolt fastening structure for a conductive member, comprising:

6. 3. The bolt fastening structure for a conductive member according to claim 2, The protrusion has a cross section formed in a generally rectangular shape.

1. A bolt fastening structure for a conductive member, comprising:

7. 4. The bolt fastening structure for a conductive member according to claim 2 or 3, The protrusions and the recesses are formed by press molding.

1. A bolt fastening structure for a conductive member, comprising:

8. 4. The bolt fastening structure for a conductive member according to claim 2 or 3, One or both of the first conductive member and the second conductive member is subjected to a surface treatment.

1. A bolt fastening structure for a conductive member, comprising:

9. 9. The bolt fastening structure for a conductive member according to claim 8, The surface treatment is Ag plating.

1. A bolt fastening structure for a conductive member, comprising:

10. 9. The bolt fastening structure for a conductive member according to claim 8, The surface treatment is Sn plating.

1. A bolt fastening structure for a conductive member, comprising:

11. 9. The bolt fastening structure for a conductive member according to claim 8, The surface treatment is Ni plating.

1. A bolt fastening structure for a conductive member, comprising:

12. 4. The bolt fastening structure for a conductive member according to claim 2 or 3, the bolt is a flanged bolt, The nut is a flanged nut.

1. A bolt fastening structure for a conductive member, comprising:

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