JP2000150013A - Bus bar welding structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To electrically connect bus bars stacked without decreasing the number of tab terminals by interposing a welding part of a tab terminal member having an almost L shaped cross section between pattern parts of two bus bars to be stacked, and welding from the surface of the pattern part of at least one bus bar. SOLUTION: A tab terminal member is formed by blanking a plate material having almost uniform thickness in a specified shape and bending in an L shape, and a welding part 110 is interposed between pattern parts 200, 250 of a bus bar from top and bottom. In welding, laser beams are irradiated almost aslant at a part facing a welding part 110 of a tab terminal 100. Laser beams X melt a pattern part 250 of the bus bar on a bottom layer through the pattern part 200 of the bus bar on a top layer and the tab terminal member 100 like a melting part 300. A recess 451 is formed in a part facing the melting part 300 of an insulating substrate 450 on the bottom layer in order to prevent the deformation of the insulating substrate caused by heat in welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric connection box used for branch connection of an automobile wire harness or the like to various electric components, and more particularly, to a connection portion between a bus bar pattern portion and a tab terminal member accommodated therein. The present invention relates to a busbar welding structure.

[0002]

2. Description of the Related Art An electrical junction box used for branch connection of an automobile wire harness or the like to various electrical components has a branch connection point concentrated in one place, and the wiring is rationally and economically branched. And various types of wire harnesses have been developed as the density of the wire harnesses has increased.

FIG. 4 shows a general structure of a conventional electric junction box. The bus bars 71 to 73 are formed by punching the hoop material 6 into a predetermined shape by using a press die, and further, tub terminal portions 71a, 71b, 72a, 72b, 73a,
73b are formed by bending up and down. Each of the bus bars 71 to 73 includes an insulating plate 81
To the upper cover 9 of the electric junction box 9
1 and the lower cover 92. And
Each of the tab terminals 71a, 71b, 72a, 72b, 73
The fuses 11 and relays 12, which are external components, are connected to a and 73b via the relay terminal 10 and the like, and a connector on the integration side is directly connected from the outside.

FIG. 5 shows the details of the laminated structure of the bus bars 71 and 72. The height of the tab terminal 72 a bent upward from the middle bus bar 72 is equal to the height of the upper insulating plate 81.
Are set so that the height thereof is equal to the height of the tab terminal 71a bent upward from the bus bar 71 of the upper layer in a state where the tab terminal 71a penetrates. Similarly, a tab terminal 73 a (not shown) bent upward from the lower bus bar 73 passes through the middle insulating plate 82 and the upper insulating plate 81, and extends upward from the upper bus bar 71. Bent tab terminal 7
The height is set to be equal to 1a.

Similarly, the tab terminal 72b bent downward from the middle bus bar 72 is attached to the lower insulating plate 83.
A tab terminal 73b (not shown) bent downward from the lower bus bar 73 while penetrating the tab terminal 73b (not shown).
And the tab terminals 71b bent downward from the upper bus bar 71.
Also, the tab terminals 73 b bent downward from the lower bus bar 73 in a state penetrating the middle insulating plate 82 and the lower insulating plate 83 are set to have the same height.

[0006] In recent years, a plurality of electrical junction boxes distributed and mounted in an automobile have been consolidated into one and arranged in a center cluster or the like, and a wire harness connecting between the electrical junction boxes has been simplified. Attempts have been made to reduce the number of lines (line saving). Therefore, the number of circuits in the electrical junction box increases to about 80 to 100 due to the integration of the electrical junction box, and the number of stacked
A bus bar laminated structure of 10 layers is required.

As the number of stacked bus bars increases, the number of laminated plates through which the tab terminal portions of the bus bar of each layer must pass also increases. Therefore, in order to secure the height of the tab terminal portions, the tab terminal portions to be bent and raised are required. Needs to be lengthened. Since the tab terminal portion is punched out of the hoop material 6 together with the pattern portion, if the length of the tab terminal portion is increased,
The length of the pattern portion becomes relatively short. That is, if a bus bar having a multilayer structure is formed by punching and bending by a press in the same manner as in the related art, the pattern portion of the bus bar becomes short, and there is a problem that the number of circuits cannot be increased despite the increase in the number of layers.

In order to solve this problem, the present applicant has
It has been proposed to utilize a laser welding technique to separate the tab terminal portion from the pattern portion (referred to as a tab terminal member) and to weld the tab terminal member to the pattern portion. In this way, by welding the tab terminal member to the pattern portion, the space required for bending and raising the tab terminal from the pattern portion of the conventional bus bar becomes unnecessary, and the pattern portion can be extended to that portion. Become. As a result, it is possible to reduce the size and density of the bus bar.

[0009]

Incidentally, in the electric junction box, there are cases where it is necessary to electrically connect the upper bus bar and the middle or lower bus bar. In this case, conventionally, connection between the tab terminals has been performed by a relay terminal, a joint connector, or the like. However,
When tab terminals are used to connect busbars inside the electrical junction box, the number of tab terminals that can be connected to external components and connectors is reduced accordingly, and the number of circuits cannot be increased so much despite the increase in the number of layers. There was a problem that.

In particular, when welding the tab terminal member and the pattern portion of the bus bar, if the tab terminals are connected by using a welding technique such as laser welding on the one hand and a relay terminal or a connector on the other hand, There was a problem that the laser welding technology was not effectively utilized.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In an electric connection box in which a tab terminal member and a bus bar pattern portion are connected by welding, the electric connection box can be connected to external parts and the like. An object of the present invention is to provide a bus bar welding structure that can electrically connect stacked bus bars by welding without reducing the number of tab terminals.

[0012]

In order to solve the above-mentioned problems, a bus bar welding structure according to the present invention is provided by forming a portion to be welded of a tab terminal member having a substantially L-shaped cross section into a pattern portion of two bus bars to be laminated. And welding by supplying energy from the surface of the pattern portion of at least one of the bus bars.

In the above configuration, welding may be performed by supplying energy from the surfaces of the pattern portions of the two bus bars, respectively.

Alternatively, the pattern portion of one of the bus bars is displaced so that a part of the portion to be welded of the tab terminal member is exposed, and the surface of the shifted bus bar pattern portion and the exposed portion of the tab terminal member to be welded are exposed. The welding may be performed by supplying energy from the surface.

[0015] The pattern portion of the two bus bars and the tab terminal member may be welded in a state where they are placed on the insulating substrate.

In particular, it is preferable that the insulating substrate has an opening or a recess at a position facing a welding portion between the bus bar pattern portion and the tab terminal member.

Preferably, the pattern portion of the bus bar and the tab terminal member are welded by any one of laser welding, resistance welding, and ultrasonic welding.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows the configuration of a first embodiment of a bus bar welding structure according to the present invention. In the figure, 100 denotes a tab terminal member, and 200 and 250 each denote a pattern portion of a bus bar to be laminated, particularly a portion to which the tab terminal is welded. 400 and 450 are insulating substrates, respectively. Further, the melted portion is represented by 300.

The tab terminal member 100 is formed by punching a material having a substantially uniform thickness into a predetermined shape and further bending the material into a substantially L-shape. Welded portion 110 of tab terminal member 100
Are the bus bar pattern portions 200,
250.

At the time of laser welding, as shown by an arrow X in the figure, the laser beam is applied to the pattern portion 20 of the upper bus bar.
In the surface of the “0”, the light is irradiated slightly obliquely, particularly at a portion facing the welded portion 110 of the tab terminal member 100. The laser beam X, as shown by the melted portion 300,
These portions are melted so as to reach the lower bus bar pattern portion 250 through the upper bus bar pattern portion 200 and the welded portion 110 of the tab terminal member 100. In order to prevent the insulating substrate 450 from being deformed due to heat during laser welding, a concave portion 451 is formed in a portion facing the molten portion 300 in the lower insulating substrate 450.

Generally, since the dimensions of the tab terminal portion of the bus bar are determined by standards, it is impossible to reduce the thickness of the material of the tab terminal member 100 to a certain value (for example, 0.7 mm) or less. Also, the bus bar pattern part 2
The width and thickness of 00 and 250 are determined in order to pass a constant current. Thus, for example, as shown in FIG.
Tab terminal member 100 and bus bar pattern portion 20
When the plate thicknesses of 0 and 250 are made the same, the tab terminal member 100 and the pattern portions 200 and 250 of the bus bar are melted using a thick plate welding technique among known laser welding techniques so that a so-called keyhole phenomenon occurs. .

(Second Embodiment) Next, the configuration of a second embodiment of the bus bar welding structure of the present invention is shown in FIG. In FIG. 2, members denoted by the same reference numerals as those in the first embodiment are substantially the same.

As can be seen from FIG. 2, in the second embodiment, a laser beam X is irradiated from the respective surfaces of the pattern portions 200 and 250 of the two bus bars. An opening 4 is formed in a portion of the lower insulating substrate 450 facing the molten portion 300.
52 are formed, and the laser beam X is irradiated from the portion of the opening 452 to the surface of the pattern portion 250 of the lower bus bar.

In the second embodiment, since the welding is performed by supplying energy such as a laser beam from each surface of the pattern portions 200 and 250 of the two bus bars, each molten portion 3 is welded.
In the case of 00, only one of the tab terminal member 100 and the bus bar pattern portions 200 and 250 may be melted. Therefore, the required penetration depth becomes shallower than in the case of the first embodiment. Therefore, even if a laser device having a low energy density is used, the melting portion 300 can be sufficiently melted.

In the second embodiment, since the required penetration depth is small, it is possible to use a thin plate welding technique among the laser welding techniques. Here, of the laser welding techniques, differences in welding mechanisms between thin plate welding and thick plate welding will be briefly described.

In the case of thin plate welding, the surface of one of the members to be irradiated with the laser beam (the pattern portion 200 of the bus bar,
Since the distance from the surface of the laser beam to the joining surface of the two members (tab terminal member 100 and bus bar pattern portion 200) to be welded to each other is short (the penetration depth required for welding is small), Even if the energy density is lowered, the portion irradiated with the laser beam is melted relatively instantaneously.

On the other hand, in the case of thick plate welding, three members to be welded from the surface of one member irradiated with the laser beam (in the first embodiment, the surface of the bus bar pattern portion 200). Since the distance to the final joint surface (tab terminal member 100 and busbar pattern portion 250) is long (the penetration depth necessary for welding is deep), irradiation is performed to melt the metal to the deep portion of the portion to be welded. It is necessary to increase the energy of the laser beam and extend the irradiation time. Further, the previously melted portion is continuously irradiated with the laser beam and the energy is continuously supplied, so that the melted metal evaporates and scatters to form a keyhole. Due to the formation of the keyhole, the laser beam also reaches a deeper portion, and that portion is melted, and the melting of the metal finally reaches the joining surface between the tab terminal member 100 and the pattern portion 250 of the bus bar, thereby welding. Complete.

As the type of the laser device, generally, CO 2 is used.
_{A two-} laser, a YAG laser, or the like can be used, but a YAG laser having a good light-collecting property is suitable for welding a small part having a small penetration depth and a small penetration amount. In addition, YAG laser welding is non-contact, has a small heat affected layer, consumes little power and is small in size, can be easily used for three-dimensional welding because of the use of optical fibers, and splits the beam into multiple parts. It also has excellent effects such as multi-point simultaneous welding and easy automation.

(Third Embodiment) Next, FIG. 3 shows the configuration of a busbar welding structure according to a third embodiment of the present invention. In FIG. 3, members denoted by the same reference numerals as those in the first or second embodiment are substantially the same.

As can be seen from FIG. 3, in the third embodiment, the pattern portion 200 of one bus bar is displaced so as to expose a part of the portion 110 to be welded of the tab terminal member 100, and the bus bar is displaced. Busbar pattern part 2
The laser beam X is applied to the surface of the first portion 00 and the surface of the exposed portion 110 of the tab terminal member 100, respectively.

In the third embodiment, since a plurality of laser beams X are irradiated from the same direction, the lower insulating substrate 450 is heated by the heat during laser welding similarly to the first embodiment. A concave portion 451 is formed in a portion facing the melted portion 300 in order to prevent deformation of the resin.

As in the second embodiment, in each of the melting portions 300, only one of the tab terminal member 100 and the bus bar pattern portions 200 and 250 may be melted. Therefore, the required penetration depth becomes shallower than in the case of the first embodiment. Therefore, even if a laser device having a low energy density is used, the melting portion 300 can be sufficiently melted.

Note that the third embodiment is not limited to the above configuration, and the pattern portion 250 of the lower bus bar is shifted,
Further, as in the second embodiment, an opening 452 may be provided in the lower insulating substrate 450, and the laser beam may be irradiated from the opening 452.

(Other Embodiments) In each of the above embodiments, the pattern portions 200 and 250 of the two bus bars and the tab terminal member 100 are attached to the insulating substrates 400 and 450, respectively.
It was configured to be welded in a state where it was placed on the top, but the present invention is not limited to this, and the pattern portions 200 and 250 of the two bus bars and the welded portion 110 of the tab terminal member 100 were welded on a jig. After that, the insulating substrates 400, 4
It may be configured to be held at 50.

In each of the above embodiments, the pattern portions 200 and 250 of the bus bar and the portion 110 to be welded of the tab terminal member 100 are welded by laser welding. However, the present invention is not limited to this. Sonic welding may be used.

Further, the tab terminal member 100 and the pattern portions 200 and 250 of the bus bar are desirably plated with tin or the like as a measure against rust.

[0037]

As is clear from the above description, according to the bus bar welding structure of the present invention, the portion to be welded of the tab terminal member having a substantially L-shaped cross section is formed by the pattern portion of the two bus bars to be laminated. And welding is performed by supplying energy from the pattern portion surface of at least one bus bar, so that the bus bars of each layer laminated inside the electric connection box can be connected by direct welding without using relay terminals or connectors. It becomes possible.

Further, by filling the step between the bus bars of each layer with the tab terminal member, it is possible to prevent an unreasonable force from being applied to the welded portion, thereby improving the reliability of the electric junction box. Furthermore, since one tab terminal can be simultaneously connected to two layers of bus bars, it is possible to increase the number of tab terminals and the number of circuits that can be connected to external components and the like in the electric connection box.

In addition, welding is performed by supplying energy from the surface of the pattern portions of the two bus bars, respectively, or the pattern portion of one bus bar is arranged so as to be shifted so that the portion to be welded of the tab terminal member is exposed. Welding by supplying energy from the surface portion of the shifted bus bar and the exposed portion of the tab terminal member to be welded can reduce the penetration depth of the molten portion and reduce the energy density supplied to the welded portion. It is possible to do. For example, in the case of laser welding, it becomes possible to use a laser device having a low energy density, and it is possible to reduce costs and the like required for welding equipment.

Further, by welding the pattern portions of the two bus bars and the tab terminal members while each of them is placed on an insulating substrate, a positioning jig or the like is not required at the time of welding, and the electric connection box is assembled. The process can be simplified. In particular, the insulating substrate is provided with an opening or a concave portion at a position facing the welding portion between the bus bar pattern portion and the tab terminal member, thereby making it possible to prevent deformation of the insulating substrate due to heat during welding.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a first embodiment of a bus bar welding structure of the present invention.

FIG. 2 is a sectional view showing a configuration of a second embodiment of the bus bar welding structure of the present invention.

FIG. 3 is a sectional view showing a configuration of a third embodiment of the bus bar welding structure of the present invention.

FIG. 4 is an exploded perspective view showing a procedure for processing and assembling a conventional bus bar.

FIG. 5 is a perspective view showing a configuration of a laminated portion in a conventional bus bar.

[Explanation of symbols]

 100: tab terminal member 110: welded portion 200: bus bar pattern portion 250: bus bar pattern portion 300: fused portion 400: insulating substrate 450: insulating substrate 451: concave portion 452: opening

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shigeki Yamane 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi F-term in Harness Research Institute, Inc. (reference) 5E085 BB11 CC03 DD03 EE06 FF08 HH12 JJ50

Claims (6)

[Claims] 1. A portion to be welded of a tab terminal member having a substantially L-shaped cross section is sandwiched between two bus bar pattern portions to be laminated, and energy is supplied from at least one bus bar pattern portion surface to perform welding. A bus bar welding structure characterized by the above-mentioned. 2. The bus bar welding structure according to claim 1, wherein the welding is performed by supplying energy from the surfaces of the pattern portions of the two bus bars, respectively. 3. The pattern portion of one bus bar is shifted so as to expose a part of the portion to be welded of the tab terminal member, and the pattern portion surface of the shifted bus bar and the exposed portion of the tab terminal member to be welded. The bus bar welding structure according to claim 1, wherein the welding is performed by supplying energy from the surface. 4. The bus bar welding structure according to claim 1, wherein the pattern portions of the two bus bars and the tab terminal members are welded in a state of being placed on the insulating substrate, respectively. 5. The bus bar welding structure according to claim 4, wherein the insulating substrate has an opening or a recess at a position facing a welding portion between the bus bar pattern portion and the tab terminal member. 6. The bus bar pattern portion and the tab terminal member are welded by any one selected from laser welding, resistance welding, and ultrasonic welding. The busbar welding structure according to 1.