Conductive member, connection structure of conductive member, and connection method of conductive member

Abstract

To provide a conductive member or the like that can efficiently destroy an oxide film to provide electrical continuity even during repeated connection work.SOLUTION: A conductive member 3a is, for example, a flat bus bar or the like, and is made of aluminum and electrically connected to the conductive member 3b. A connection portion 11 with the conductive member 3b is provided in a portion of the conductive member 3a. A plurality of protrusions 15a, 15b, and 15c are formed on the surface of the conductive member 3a near the connection portion 11. The protrusions are organized into multiple groups with different heights. For example, there is a group consisting of the tallest protrusions 15a, a group consisting of the next tallest protrusions 15b, and a group consisting of the shortest protrusions 15c.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an aluminum conductive member or the like that is joined to another conductive member. [Background technology]

[0002] For example, automobiles use many electrical components, such as electrically driven electrical devices and sensors that perform various controls. These electrical components are connected to a battery, which is a power supply source, via various conductive members as power lines and signal lines. One example of such an electrical wiring structure is a method that uses a trunk bus bar connected to the battery and connects predetermined electrical devices, branch lines, etc. to the trunk bus bar.

[0003] On the other hand, aluminum is sometimes used as a conductive material to reduce weight. Aluminum is known for its light weight and high conductivity, but a dense oxide about 10 μm thick forms on the surface of aluminum. Therefore, when an aluminum conductive material is brought into contact with another conductive material to achieve electrical continuity, the oxide increases resistance.

[0004] In response to this, a method has been proposed in which hemispherical protrusions are formed on the surface of an aluminum conductive member, and the oxide film on the surface is destroyed by deformation of the protrusions when fastened (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-82637 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, once connection is made, the oxide film is formed again in the crushed state of the projections, so the effect cannot be fully obtained when the connection work is redone. Also, although the upper and lower limits of the projection height are described, the projection height is formed within a predetermined range of variation, so the effect cannot necessarily be obtained with good reproducibility.

[0007] The present invention has been made in consideration of such problems, and aims to provide a conductive member or the like that can efficiently destroy an oxide film and establish conductivity even during repeated connection work. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the first invention is a conductive component made of aluminum that is electrically connected to another component, and is characterized in that it comprises a connection portion with the other component and a plurality of protrusions formed on its surface near the connection portion, the protrusions consisting of a plurality of groups of different heights.

[0009] Preferably, the base area of the protrusions in the relatively short group is greater than the base area of the protrusions in the relatively tall group.

[0010] Around the connection portion, a group of protrusions with a relatively low height may be arranged in an area close to the connection portion, and a group of protrusions with a relatively high height may be arranged in an area away from the connection portion.

[0011] The protrusion is preferably cone-shaped.

[0012] The protrusions may be made up of at least three groups of different heights.

[0013] According to the first invention, by forming multiple protrusions on the surface, when the connector is tightened and connected to other conductive members, the protrusions are crushed, destroying the oxide film and exposing the aluminum base material. This allows for a high conductivity connection. Furthermore, by intentionally varying the protrusion height and forming multiple groups with different heights, the protrusions can be selectively crushed for each group to make a connection. Therefore, by adjusting the torque, the protrusions can be reliably deformed, the oxide film can be destroyed, and a connection can be made even during multiple connection operations.

[0014] Furthermore, by making the base area of the relatively short protrusions larger than the base area of the relatively tall group of protrusions, the destruction area of the oxide film can be ensured even when connecting multiple times.

[0015] Furthermore, by arranging a group of relatively low-height protrusions in an area around the connection portion close to the connection portion and a group of relatively high-height protrusions in an area away from the connection portion, it is possible to secure an area for arranging the tallest protrusions, and therefore it is possible to arrange a large number of such protrusions.

[0016] Furthermore, by making the projections cone-shaped, the area on which the oxide film is formed is reduced, and deformation becomes easier when tightened, so that the oxide film can be destroyed reliably.

[0017] Furthermore, by forming the protrusions in at least three groups of different heights, the effect can be demonstrated even when the connection work is repeated three or more times.

[0018] The second invention is an electrical connection structure between the conductive member of the first invention and another member, characterized in that the surface of the conductive member on which the protrusion is formed is in surface contact with the other member and connected at the connection portion, and at least a portion of the protrusion is crushed.

[0019] According to the second aspect of the present invention, at the contact portions between the conductive members, the protrusions are crushed to form surface contact, so that the oxide film at the contact portions is destroyed, and electrical continuity can be obtained efficiently.

[0020] The third invention is a method for electrically connecting the conductive member of the first invention to another member, comprising a first connection step of bringing the surface of the conductive member on which the protrusions are formed into surface contact with the connection object and connecting them at the connection portion, and a second connection step of removing the conductive member from the connection object, and again bringing the surface of the conductive member on which the protrusions are formed into surface contact with the connection object and connecting them at the connection portion, wherein in the first connection step, the connection is made by crushing the protrusions of the relatively tallest group, and in the second connection step, the connection is made by crushing the protrusions of the next lowest group, and the connection torque in the second connection step is set higher than the connection torque in the first connection step.

[0021] According to the third invention, in the second connection step, the projections of the low height group can also be crushed to make the connection, so that the oxide film at the contact portion is destroyed and electrical continuity can be obtained efficiently. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a conductive member or the like that can efficiently destroy an oxide film and establish electrical continuity even during repeated connection operations. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2A is a perspective view of the connection structure 1, and FIG. 2B is a side view of the connection structure 1. [Figure 2] 1A is a plan view of the conductive member 3a, FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A, and FIG. 1C is an enlarged view of part B in FIG. [Figure 3](a) is a diagram showing the state before the conductive members 3a and 3b are connected, (b) is a diagram showing the state after the protrusion 15a has been crushed and the conductive members 3a and 3b have been connected, (c) is a diagram showing the state after the conductive member 3b has been removed from (b), (d) is a diagram showing the state after the protrusion 15b has been crushed and the conductive members 3a and 3b have been connected, and (e) is a diagram showing the state after the protrusion 15c has been crushed and the conductive members 3a and 3b have been connected. [Figure 4] (a) is a partial enlarged view of FIG. 3(a), (b) is a partial enlarged view of FIG. 3(b), (c) is a partial enlarged view of FIG. 3(d), and (c) is a partial enlarged view of FIG. 3(e). [Figure 5] 1(a) is a diagram showing another embodiment of the conductive member 3a, and FIG. 1(b) is a diagram showing the connection structure 1a. [Figure 6] FIG. 10 is a plan view of another embodiment of the conductive member 3a. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1(a) is a perspective view showing a connection structure 1 in which conductive members 3a and 3b are electrically connected, and Fig. 1(b) is a side view of the connection structure 1. The conductive members 3a and 3b are overlapped so as to be in surface contact with each other, and are connected by a bolt 5 and a nut 9 that pass through the conductive members 3a and 3b. The conductive members 3a and 3b are sandwiched between the bolt 5 and the nut 9 via a washer 7.

[0025] The conductive member 3a is, for example, a flat bus bar or the like that is electrically connected to the conductive member 3b and is made of aluminum. Note that the aluminum material is not limited to pure aluminum and includes aluminum alloys.

[0026] The conductive member 3b is a member having a joining surface that can come into surface contact with the conductive member 3a, and the material is not particularly limited. For example, the conductive member 3b may be made of aluminum, the same as the conductive member 3a, or may be made of copper (pure copper or copper alloy). The conductive member 3b may be a bus bar, a terminal portion of an electrical device, or the vehicle body itself.

[0027] Next, the conductive member 3a will be described in detail. Fig. 2(a) is a plan view of the conductive member 3a, Fig. 2(b) is a cross-sectional view taken along line AA in Fig. 2(a), and Fig. 2(c) is an enlarged conceptual diagram of part B in Fig. 2(b). A connection part 11 with the conductive member 3b is provided in a part of the conductive member 3a. As mentioned above, the connection part 11 is a hole through which a bolt is inserted. Note that instead of a hole, a male screw may be directly erected.

[0028] Around the connecting portion 11, a protrusion-forming portion 13 is formed in a portion that will be in contact with the conductive member 3b. The protrusion-forming portion 13 is composed of a plurality of protrusions 15a, 15b, and 15c. That is, in the vicinity of the connecting portion 11, a plurality of protrusions 15a, 15b, and 15c are formed on the surface of the conductive member 3a.

[0029] The vertical cross section of the protrusions 15a, 15b, and 15c is approximately pyramidal. That is, the width (diameter) of the protrusions 15a, 15b, and 15c decreases toward the tip, and the tip is sharp. The cross section of the protrusions 15a, 15b, and 15c parallel to the surface of the conductive member 3b may be circular or rectangular. Alternatively, the uneven cross section may be continuous in the depth direction of the drawing.

[0030] Here, the protrusions are made up of multiple groups of different heights. In the illustrated example, there is a group (C in the figure) made up of the relatively tallest protrusions 15a, a group (D in the figure) made up of the next tallest protrusions 15b, and a group (E in the figure) made up of the shortest protrusions 15c. Note that two or more groups of protrusions with different heights are sufficient, but it is desirable to have at least three or more groups with different heights.

[0031] Here, the height H1 of the tallest protrusion 15a is, for example, about 0.8 to 1.3 mm, the height H2 of the second tallest protrusion 15b is, for example, about 0.5 to 1.0 mm, and the height H3 of the third tallest protrusion 15c is, for example, about 0.2 to 0.7 mm. The difference in height between the protrusions corresponds to the amount of squeezing of the protrusions during bonding, which will be described later.

[0032] Furthermore, the base width W1 of protrusion 15a is narrower than the base width W2 of protrusion 15b, which is narrower than the base width W3 of protrusion 15c. That is, the base area of the relatively low-height protrusions is larger than the base area of the relatively high-height protrusions. The base width W1 of the tallest protrusion 15a is, for example, 400 μm or less.

[0033] The protrusions 15a, 15b, and 15c do not have to be arranged in the order shown in the figure, and may be arranged randomly. Also, the ratio of the numbers of the protrusions 15a, 15b, and 15c is not limited to the example shown in the figure, but the number of protrusions with small base areas and high heights is relatively large, and the number of protrusions with small base areas and low heights is relatively small.

[0034] The method for forming the protrusions 15a, 15b, and 15c is not particularly limited, but they can be formed by die casting, electric discharge machining, chemical conversion treatment, etching, laser processing, cutting, knurling, etc. When forming the protrusions by post-processing, masking or the like is performed appropriately, and protrusions of different heights can be formed by partially changing the conditions.

[0035] Next, a method for electrically connecting a conductive member 3a to another conductive member 3a will be described. Fig. 3(a) is a conceptual diagram showing the state before the conductive members 3a and 3b are connected. First, the protrusion-forming portion 13 of the conductive member 3a is placed opposite the conductive member 3b to be connected.

[0036] Fig. 4(a) is a partially enlarged view of the state of Fig. 3(a). As described above, an oxide film 17 is formed on the surface of the conductive member 3a. That is, in the protrusion-forming portion 13, the oxide film 17 is formed on the surface of each of the protrusions 15a, 15b, and 15c.

[0037] In this state, when the bolt 5 (FIG. 1) is tightened at the connection portion 11 (FIG. 2), the surface (the surface on which the protrusions are formed) of the conductive member 3a and the surface of the conductive member 3b come into surface contact, and the opposing surfaces are pressed together. As a result, the tip of the protrusion 15a is crushed, as shown in FIG. 3(b). By tightening the bolt 5 with the torque required to crush the protrusion 15a to a height near the tip of the protrusion 15b, the conductive member 3a and the conductive member 3b are joined together.

[0038] Fig. 4(b) is a partially enlarged view of the state of Fig. 3(b). When the bolt 5 is tightened, the deformation in the vicinity of the tip of the protrusion 15a destroys the oxide film 17 on the surface, exposing the base material of the conductive member 3a. This allows the conductive member 3a and the conductive member 3b to come into contact without the oxide film 17 in between, enabling efficient electrical connection (first connection step).

[0039] As the amount of crushing of protrusion 15a increases, the tightening torque of bolt 5 increases monotonically. On the other hand, when the surface of conductive member 3b reaches protrusion 15b, the torque required for tightening increases sharply. This makes it easy to know when the bolt has been tightened to the height of protrusion 15b, and by setting a torque that does not crush protrusion 15b, it is possible to reliably crush protrusion 15a to near the height of protrusion 15b.

[0040] That is, in the first connecting step, the conductive members 3a and 3b can be connected by crushing the relatively highest group of protrusions 15a, while leaving protrusions 15b and 15c intact. In the connection structure for conductive members obtained in this manner, with at least some of the protrusions crushed, the protrusion-forming surface of conductive member 3a comes into surface contact with other members and is connected at connection portion 11.

[0041] Next, a process of removing and reconnecting conductive member 3b to conductive member 3a will be described. Fig. 3(c) shows the state after conductive member 3b has been removed. For example, to reroute wiring or in the event of a connection error, the bolt 5 that was once tightened may be loosened and conductive member 3b may be tightened again, or a different conductive member may be connected.

[0042] Fig. 3(d) is a diagram showing the state in which the conductive member 3b, which is the connection target, has been fastened again from the state shown in Fig. 3(c), and Fig. 4(c) is an enlarged view of Fig. 3(d). As described above, the conductive member 3a is removed from the connection target, the surface on which the protrusion of the conductive member 3a is formed is brought into surface contact with the connection target again, and the bolt 5 is fastened, thereby connecting the conductive members 3a and 3b at the connection portion 11 (second connection step).

[0043] In the second connecting step, the projections 15b in the next lowest group are crushed to connect to the projections 15a. At this time, the connecting torque in the second connecting step is set higher than the connecting torque (bolt tightening torque) in the first connecting step.

[0044] In the second connecting step, as shown in Fig. 4(c), the tip of projection 15b is crushed. By tightening bolt 5 with the torque required to crush projection 15b to the height near the tip of projection 15c, conductive member 3a and conductive member 3b are joined. At this time, tightening bolt 5 causes deformation near the tip of projection 15b, destroying oxide film 17 on the surface and exposing the base material of conductive member 3a. This allows conductive member 3a and conductive member 3b to contact without oxide film 17, resulting in efficient electrical connection.

[0045] Even in this case, the protrusions 15a are further crushed, but the tips of the crushed protrusions 15a become flat, and an oxide film 17 is immediately formed on the flat surface when the conductive member 3b is removed. For this reason, in the second connecting step, it is difficult to efficiently destroy the oxide film 17 on the contact surface by simply further crushing the protrusions 15a, which have flat tips after the first connecting step. On the other hand, the protrusions 15b are the first to be crushed in the second connecting step, and if they are pyramidal, the deformation at the tips is particularly large, so that the oxide film 17 can be efficiently destroyed.

[0046] As mentioned above, the tightening torque of the bolt 5 increases monotonically as the protrusion 15b (and the protrusion 15a) is crushed. On the other hand, when the surface of the conductive member 3b reaches the protrusion 15c, the torque required for tightening increases sharply. Therefore, it is easy to know when the bolt has been tightened to the height of the protrusion 15c, and by setting the torque so that the protrusion 15c is not crushed, the protrusion 15b can be reliably crushed to near the height of the protrusion 15c.

[0047] Fig. 3(e) shows the state in which conductive member 3b is removed after the second connection step and then reconnected to conductive member 3a, and Fig. 4(d) is a partially enlarged view. As mentioned above, if there are three groups of protrusions with different heights, the third connection can also be made by crushing the new protrusions (third connection step).

[0048] In the third connecting step, as shown in Fig. 4(d), the tip of projection 15c is crushed. By tightening bolt 5 with the torque required to crush projection 15c to a predetermined height, conductive member 3a and conductive member 3b are joined. At this time, tightening bolt 5 causes deformation near the tip of projection 15c, destroying oxide film 17 on the surface and exposing the base material of conductive member 3a. This allows conductive member 3a and conductive member 3b to contact without oxide film 17 in between, resulting in efficient electrical connection.

[0049] As described above, according to this embodiment, the oxide film 17 on the surface of the conductive member 3a can be efficiently destroyed to connect to the conductive member 3b. Furthermore, by varying the heights of the protrusions 15a, 15b, and 15c, new protrusions can be crushed during each of multiple connection operations, which allows the oxide film 17 to be efficiently destroyed and connections to be made.

[0050] Furthermore, since the projections 15a, 15b, and 15c are cone-shaped, when the projections 15a, 15b, and 15c are crushed, the amount of deformation is large, and the oxide film 17 can be destroyed efficiently.

[0051] Furthermore, by increasing the base area of the relatively short protrusions, the shorter protrusions can ensure a larger contact area with a smaller crushing margin. For example, when crushing protrusion 15b, protrusion 15a must also be crushed at the same time, so a torque greater than that required to crush protrusion 15b is required. Therefore, if the crushing margin of protrusion 15b (the difference in height between protrusions 15b and 15c) is increased, protrusion 15a must be crushed accordingly.

[0052] In response to this, by gradually setting the height of the protrusions so that the crushing allowance of protrusion 15b (the difference in height between protrusions 15b and 15c) becomes smaller than the crushing allowance of protrusion 15a (the difference in height between protrusions 15a and 15b), the amount of tightening during subsequent work can be reduced as the second and third connection steps are carried out.

[0053] Such a connection structure can be applied, for example, to the connection between a vehicle body and a ground terminal. Fig. 5(a) is a diagram showing an example in which the conductive member 3a is a ground terminal. For example, a ground wire 19 is connected to the ground terminal, which is a round terminal made of aluminum. A protrusion-forming portion 13 is provided on at least one surface of the ground terminal. That is, a plurality of protrusions are formed around the connection portion 11 (hole) of the ground terminal.

[0054] FIG. 5(b) is a diagram showing a connection structure 1a in which the conductive member 3b is the vehicle body and the conductive member 3a, which is the earth terminal, is connected to the vehicle body. The earth terminal is joined to the vehicle body by a bolt 5. At this time, the protrusion of the earth terminal deforms and comes into contact with the vehicle body. In this way, this embodiment can also be applied to the earth terminal. Note that while an example has been shown in which the conductive member 3b is the vehicle body and the conductive member 3a is the earth terminal, the opposite may also be true: the conductive member 3a is the vehicle body and the conductive member 3b is the earth terminal.

[0055] The arrangement of the protrusions 15a, 15b, and 15c is not particularly limited, but the formation regions of the protrusions 15a, 15b, and 15c may be changed. Fig. 6 is a diagram showing the regions of the protrusion formation portions 13a, 13b, and 13c. As shown in Fig. 6, the protrusion formation portions for each group of protrusion heights may be arranged concentrically around the connecting portion 11.

[0056] For example, protrusions 15c are formed in protrusion-forming portion 13c closest to connection portion 11, protrusions 15b are formed in protrusion-forming portion 13b formed on the outer periphery of protrusion-forming portion 13c, and protrusions 15a are formed in protrusion-forming portion 13a on the outermost periphery of protrusion-forming portion 13b. That is, around connection portion 11, a group of relatively low protrusions 15c is arranged in the area close to connection portion 11, and a group of relatively high protrusions 15b, 15a are arranged in this order in the area away from connection portion 11.

[0057] As mentioned above, the protrusions 15a are relatively thin, so a larger number of them are required. Therefore, by arranging the protrusions 15a on the outermost periphery, a larger formation area can be ensured. Furthermore, when tightening with the bolt 5, the closer to the connection portion 11, the greater the tightening force (pressing force) that can be exerted. As mentioned above, the tightening torque is greater when crushing a protrusion with a low height, so by arranging a protrusion with a relatively low height in a position close to the connection portion 11, the protrusion with a low height can be more reliably crushed and connected.

[0058] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not limited to the above-described embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas described in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0059] 1, 1a...Connection structure 3a, 3b... Conductive members 5....Bolt 7...Washer 9...Nut 11...Connection 13, 13a, 13b, 13c...Protrusion forming part 15a, 15b, 15c……protrusions 17……Oxide film

Claims

1. An electrically conductive member made of aluminum that is electrically connected to other members, A connection portion with another member; a plurality of protrusions formed on the surface in the vicinity of the connection portion; Equipped with The conductive member is characterized in that the protrusions are made up of a plurality of groups having different heights.

2. 2. The conductive member according to claim 1, wherein the base area of the protrusions in the relatively low group is greater than the base area of the protrusions in the relatively high group.

3. Around the connection portion, 2. The conductive member according to claim 1, wherein a group of the protrusions having a relatively low height is arranged in an area close to the connection portion, and a group of the protrusions having a relatively high height is arranged in an area away from the connection portion.

4. 2. The conductive member according to claim 1, wherein the protrusion is cone-shaped.

5. 2. The conductive member according to claim 1, wherein the projections are arranged in groups of at least three or more different heights.

6. An electrical connection structure between the conductive member according to any one of claims 1 to 5 and another member, the surface of the conductive member on which the protrusion is formed is in surface contact with the other member and is connected to the other member at the connection portion; A connection structure for conductive members, wherein at least a portion of the protrusion is crushed.

7. A method for electrically connecting the conductive member according to any one of claims 1 to 5 to another member, comprising: a first connecting step of bringing the surface of the conductive member on which the protrusion is formed into surface contact with a connection target and connecting the connection target at the connection portion; a second connecting step of removing the conductive member from the connection object, bringing the surface of the conductive member on which the protrusion is formed into surface contact with the connection object, and connecting the conductive member at the connection portion; Equipped with A method for connecting conductive members, characterized in that in the first connecting step, the protrusions in the relatively highest group are crushed to make the connection, and in the second connecting step, the protrusions in the next lowest group are crushed to make the connection, and the connection torque in the second connecting step is set higher than the connection torque in the first connecting step.

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