JP3343066B2 - Laser welding structure of bus bar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding structure most suitable for a bus bar housed in an electric junction box, and more particularly to a structure capable of reducing laser irradiation energy and welding man-hour.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10A, a crimping portion 3a of a crimping terminal 3 for crimping and connecting a conductor 2 of an electric wire 1 is irradiated with a laser beam LB to melt the crimping portion 3a and the conductor 2. It has been proposed to perform welding.

As shown in FIG. 10 (B), a separate metal projection 5 for replenishing the molten volume is provided on the flat metal welding conductor 4, and a plurality of metal projections 5 are provided below the projection 5. Strand 2a
The conductor 2 made of
There is also proposed a method in which the projection 5 is melted and welded together with the conductor 2 by irradiating B (Japanese Patent Laid-Open No. 6-30).
No. 2341).

By the way, in an electric junction box used for branch connection of an automobile wire harness or the like to various electric components, the branch connection points are concentrated at one place, and the wiring is rationally and economically connected. With the increase in the density of wire harnesses, various types have been developed according to vehicle types or applications.

[0005] As shown in FIG. 9, the electric connection box as described above uses a press die to move the bus bar 7 A from the hoop material 6.
To 7C, and each of the bus bars 7A to 7C
The tab terminals 7a and 7b are cut and raised from the pattern portion in the vertical direction, and insulating plates 8A to 8C are interposed between the bus bars 7A to 7C, respectively. And a lower case 9B.

As shown in detail in FIG. 8 of each of the bus bars 7A to 7C, a tab terminal 7a cut upward from a middle bus bar 7B is connected to an upper insulating plate 8A.
The tab terminals 7a cut upward from the upper bus bar 7A are set so as to have the same height as the tab terminals 7a cut upward from the upper bus bar 7A. The board 8B and the upper insulating plate 8A are penetrated so that the tab terminals 7a cut and raised upward from the upper bus bar 7A are set to have the same height.

Similarly, the tab terminal 7b cut and raised from the middle bus bar 7B extends downward through the lower insulating plate 8C, and the height of the tab terminal 7b cut and raised from the lower bus bar 7C is lowered. The tab terminals 7 which are set so as to be aligned and cut and raised downward from the upper bus bar 7A.
“b” is set so as to penetrate the middle insulating plate 8B and the lower insulating plate 8C, and to have the same height as the tab terminals 7b cut and raised downward from the lower bus bar 7C.

[0010] As shown in FIG. 9, external components such as a fuse 11 and a relay 12 are inserted and connected to the tab terminals 7 a and 7 b via a relay terminal 10 and the like, and externally integrated. The connector on the side is directly inserted and connected.

When the circuit volume in the electric junction box 9 increases, the bus bars 7A (7
B, 7C), the pattern parts of the bus bars 7A to 7C of different levels, and the pattern parts of the bus bars 7A to 7C, and other wiring members (FPC, PC).
B or a conductor such as an electric wire) with a connector.

On the other hand, in recent years, a plurality of electric connection boxes dispersedly mounted in an automobile are integrated into one and arranged in a center cluster or the like, and a wire harness for connecting between the electric connection boxes is provided. Attempts have been made to simplify (line saving).

If the number of circuits in the electric junction box is about 40, a three-layer bus bar laminated structure as described above may be used. However, the number of circuits in the electric junction box is reduced by 80 to 100 due to integration.
When it is increased to the extent, a bus bar laminated structure of 8 to 10 layers is obtained.

With the bus bar laminated structure of eight to ten layers as described above, when the tab terminals are vertically cut from the bus bar pattern portion of each layer, the tab terminals cut and raised upward from the uppermost bus bar are formed. In order to set the height to be the same as the height of the tab terminal cut and raised from the lowermost bus bar, the maximum number of tab terminals is 8 to 1
It is necessary to set the length to penetrate as many as 0 layers of the insulating plate.

However, in order to cut a long tab terminal from the bus bar pattern portion, a space for cutting and raising the tab terminal is required in the pattern portion.
Since this space becomes a dead space and the size of the bus bar cannot be reduced in size and density, there is a problem that the number of stacked bus bars cannot be reduced.

To solve this problem, the applicant has
We have proposed a laser welding structure that makes it possible to reduce the size and density of busbars housed in electrical junction boxes by utilizing laser welding technology.

In the laser welding structure, basically, the tab terminals are not cut and raised in the vertical direction from the bus bar pattern portion, but the tab terminals are formed separately, and the separate tab terminals are connected to the bus bar pattern portion. By irradiating a laser beam, and melting and welding the tab terminal and the pattern portion, a dead space for cutting and raising the tab terminal in the pattern portion of the bus bar becomes unnecessary. By adding a pattern part to
The bus bar can be made smaller and more dense.

[0016]

SUMMARY OF THE INVENTION The present invention relates to an improvement in the laser welding structure proposed by the present applicant, and is particularly suitable for welding a bus bar housed in an electric junction box and reducing the laser irradiation energy. An object of the present invention is to provide a laser welding structure capable of reducing the number of steps and the number of welding steps for tab terminals.

[0017]

According to a first aspect of the present invention, a bent portion of a tab terminal is applied to a pattern portion of a bus bar housed in an electric junction box. The tab terminals and the bent legs are formed by laser welding the bent legs of the tab terminal to the pattern part of the tab terminal, and the tab terminals and the bent legs are formed from a plate-shaped conductor having a thickness of half the thickness required for inserting and connecting the female terminal. At the same time, the tab terminals are formed such that the conductor is folded and formed into a thickness necessary for inserting and connecting the female terminals, so that the bent legs are formed to have a half thickness of the tab terminals. It is intended to provide a laser welding structure for a bus bar characterized by the above.

According to the first aspect, the tab terminal and the bent leg portion are formed from a plate-shaped conductor having a thickness which is half the thickness required for inserting and connecting the female terminal. By folding and forming the thickness required for inserting and connecting the female terminal, the bent legs are formed to half the thickness of the tab terminal, so that the female terminal can be inserted and connected to the tab terminal. Irradiation energy for melting can be reduced by the bent legs having a small thickness while securing the thickness.

According to a second aspect of the present invention, the bent leg portion of the tab terminal is applied to the pattern portion of the bus bar housed in the electric junction box, and the bent leg portion of the tab terminal is laser-welded to the pattern portion of the bus bar. A tab terminal and a bent leg are formed from a deformed conductor having a plate thickness necessary for inserting and connecting the female terminal and a thinner plate than this plate thickness. The present invention provides a laser welding structure for a bus bar, characterized in that the bent legs are formed to have a smaller thickness than the tab terminals by being formed with a plate thickness necessary for insertion connection.

According to the second aspect, the tab terminal and the bent leg are formed from a deformed conductor having a plate thickness necessary for inserting and connecting the female terminal and a plate thickness smaller than the plate thickness. Is formed with a thickness required for inserting and connecting the female terminal, and the bent legs are formed to have a smaller thickness than the tab terminal, so that the tab terminal has a plate for inserting and connecting the female terminal. The irradiation energy for melting can be reduced by the bent leg portion having a small thickness while securing the thickness.

According to a third aspect of the present invention, the bent leg portion includes:
Forming a welding hole that penetrates to the welded body or a hemispherical recess protruding toward the welded body side, for the same reason as in claim 1 or 2, in order to reduce irradiation energy for melting, bent legs. Using the welding holes formed in the
A laser beam is directly applied to the joint interface between the bent leg and the bus bar in the welding hole, and the bent leg is welded to the bus bar pattern by melting the joint interface. Alternatively, using a hemispherical recess formed in the bent leg,
A laser beam is applied to the inside of the hemispherical recess, and the bent leg is welded to the pattern portion of the bus bar by melting due to heat trapped in the hemispherical recess.

According to a fourth aspect of the present invention, the bent leg portion includes:
When a coating material having a low reflectance of the laser beam is applied, a coating material having a low reflectance applied to the bent leg portion is used in order to reduce irradiation energy for melting for the same reason as in claim 1 or 2. By utilizing, the laser beam is applied to the paint application surface, and the bent leg is welded to the bus bar pattern portion by melting the paint application surface.

According to a fifth aspect of the present invention, a positioning projection is formed on the bent leg and a positioning hole for inserting and engaging the positioning projection is formed in the pattern portion of the bus bar. Just by inserting the positioning projections into the positioning holes in the pattern portion of the bus bar, the alignment of the tab terminals is automatically corrected.

[0024]

[0025]

[0026]

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the same components and operations as those in the conventional art are denoted by the same reference numerals, and detailed description is omitted.

FIG. 1 shows a laser welding structure according to the first embodiment. As shown in FIGS. 1A and 1B, the tab terminals 17a
Does not cut and raise the tab terminals 17a in the vertical direction from the pattern portion of the bus bar 17 as in the related art.
With the tab terminal 17a as a separate body, a bent leg 17b is integrally formed at the lower end of the tab terminal 17a.

As shown in FIG. 1 (C), the tab terminal 17a is formed from the hoop material 6 (see FIG. 9) or the like.
And the bent leg 17b are continuously punched out in the unfolded state, and both ends 17d, 17d are folded inward at the valley fold lines c, c, and the tab terminals 17a are turned upward by 90 degrees at the valley fold lines d. Bend. Thereafter, the connecting portion 17e is cut along the cutting line e.

The tab terminal 17a formed as described above
The thickness T1 required for inserting and connecting the female terminal is ensured, and the bent leg portion (irradiation portion of the laser beam LB) 17b has a thickness T2 (T1) smaller than the thickness T1 of the tab terminal 17a. > T2 ... half).

As shown in FIGS. 1A and 1B, the bent leg 17b of the tab terminal 17a is
Apply to the upper busbar 17 pattern from above,
The laser beam LB is applied to the center of the bent leg 17b from directly above.

By this irradiation, the bent leg portion 17b and the pattern portion of the bus bar 17 are melted and welded with the tab terminal 17a facing upward.

The bent leg 17 of the tab terminal 17a
b is applied to the pattern portion of the bus bar 17 from below,
When the laser beam LB is applied to the center of the bent leg 17b from directly below, the tab terminal 17a faces downward,
The bent leg portion 17b and the pattern portion of the bus bar 17 are melted and welded.

As described above, only the plate thickness T2 of the bent leg 17b can be reduced while securing the plate thickness T1 required for inserting and connecting the female terminal to the tab terminal 17a. Irradiation energy is reduced.

Further, the laser beam LB is bent and the leg 1 is bent.
When irradiation is performed at the center position of 7b, since the surface area of the bent leg 17b is large, the allowable range of the accuracy error of the irradiation position is widened. In addition, since the laser beam LB is irradiated from directly above or directly below, there are few obstacles and the irradiation distance is minimized, and it is easy to simultaneously irradiate the laser beam LB to a plurality of welding locations from the same direction. Good mass productivity.

All the tab terminals 17a of the bus bar 17
Are not welded separately, but if necessary, the tab terminals 17a
Can be used in combination with each other.

Further, as shown in FIG.
When the relay terminal 17c is integrally formed with the 7a, a separate relay terminal is not required.

When the bus bar 17 is welded by conventional resistance welding, a large jig is required for each bus bar in order to sandwich the bus bar between the electrodes. Not suitable for In the case of conventional arc welding, since the gap between the busbar and other circuits is narrow, it is necessary to insulate or widen the gap, so that the density cannot be increased, and it is necessary to ground each circuit to be welded. Therefore, processing man-hours and the like become expensive, which is not suitable for mass production. Furthermore, in ultrasonic welding, partial plating is necessary because welding cannot be performed on a portion of the bus bar that has plating, and the bus bar shape is different one by one, so jigs are required for the number of circuits, so processing man-hours and equipment are required. However, they are expensive and unsuitable for mass production.

On the other hand, in the case of the laser welding of the present invention, the laser beam LB is not in contact with the laser beam LB, so that the laser beam LB is not in contact with the laser welding, so that it can be surely performed with a simple jig. The bus bar 17 can be welded to
Since the welding seconds per location are short, mass productivity is good, and since the laser beam LB has a small beam diameter, the pitch between the bus bar 17 and the tab terminal 17a can be narrowed to improve the degree of freedom in design wiring. There is an advantage of doing so.

[0040] Among the various types of laser welding, YAG laser welding is non-contact, has a small heat-affected layer,
It has low power consumption, is small in size, can be easily used for three-dimensional welding due to the use of optical fibers, and can divide a beam into multiple parts for simultaneous multipoint welding.
It is optimal because the automation is easy and the production cost is significantly reduced.

FIG. 2 shows a laser welding structure according to a second embodiment. As shown in FIG. 2B, the tab terminal 17a is
The tab terminals 17a are formed from deformed materials having different thicknesses T1 and T2.
And the bent leg 17b are continuously punched out in the deployed state, and the tab terminal 17a is bent upward at 90 degrees at the valley fold line d. Thereafter, the connecting portion 17e is cut along the cutting line e.

The tab terminal 17a formed as described above
In the same manner as in the first embodiment, a plate thickness T1 necessary for inserting and connecting the female terminal is secured, and the bent leg portion (irradiated portion of the laser beam LB) 17b is formed with the plate thickness T1 of the tab terminal 17a. The thickness is smaller than T2 (T1> T2... Half).

Then, as shown in FIG. 2A, the bent leg 17b of the tab terminal 17a is applied to the pattern portion of the bus bar 17 on the insulating plate 18 from above, and the bent leg 17b is Is irradiated with the laser beam LB at the center position of the bent leg portion 17b and the pattern portion of the bus bar 17 in a state where the tab terminal 17a faces upward, as in the first embodiment, so that welding is performed. .

As described above, only the plate thickness T2 of the bent leg 17b can be reduced while securing the plate thickness T1 required for inserting and connecting the female terminal to the tab terminal 17a. Irradiation energy is reduced.

FIG. 3 shows a laser welding structure according to a third embodiment. Tab terminal 17a of the first embodiment shown in FIG.
And the tab terminal 17a of the second embodiment shown in FIG.
Of each bending leg (irradiation site of laser beam LB) 17
As shown in FIG. 3 (C), the bus bar 1
7, or a hemispherical recess 17 g protruding toward the bus bar 17 as shown in FIG. 3D.

Then, as shown in FIG. 3C, the bent leg 17b of the tab terminal 17a is applied to the pattern portion of the bus bar 17 on the insulating plate 18 from above, and the bent leg 17b is obliquely applied. When the laser beam LB is applied to the joint interface with the bus bar 17 in the welding hole 17f, the joint interface between the bent leg portion 17b and the pattern portion of the bus bar 17 is melted and welded.

As described above, the laser beam LB can be directly applied to the joint interface between the bent leg 17b and the bus bar 17 within the welding hole 17f by using the welding hole 17f formed in the bent leg 17b. Therefore, irradiation energy for melting can be reduced.

As shown in FIG. 3D, the top of the hemispherical concave portion 17g of the bent leg portion 17b of the tab terminal 17a is applied to the pattern portion of the bus bar 17 on the insulating plate 18 from above. When the laser beam LB is irradiated into the hemispherical recess 17g from directly above, the hemispherical recess 17g and the bus bar 1
The pattern portion 7 is melted and welded.

As described above, the laser beam LB is applied to the hemispherical concave portion 17g by utilizing the hemispherical concave portion 17g formed on the bent leg portion 17b, and the bent leg portion is melted by heat trapped in the hemispherical concave portion 17g. Can be welded to the pattern portion of the bus bar, so that the irradiation energy for melting can be reduced.

The thickness T2 of the bent leg 17b is
The tab terminal 17b need not be thinner than the plate thickness T1 (T2 = T1).

FIG. 4 shows a laser welding structure according to a fourth embodiment. Tab terminal 17a of the first embodiment shown in FIG.
And the tab terminal 17a of the second embodiment shown in FIG.
Of each bending leg (irradiation site of laser beam LB) 17
b, a low-reflectance paint (for example, black paint) 21
(See hatching).

Then, the bent leg portion 1 of the tab terminal 17a
7b is applied to the pattern portion of the bus bar 17 on the insulating plate 18 from above, and the upper surface of the bent leg 17b is irradiated with the laser beam LB from directly above, so that the bent leg 17b and the pattern portion of the bus bar 17 melt. Then, welding a is performed.

As described above, by using the paint 21 having a low reflectance applied to the bent leg 17b, the surface to which the paint 21 is applied is irradiated with the laser beam LB.
Can be welded to the pattern portion of the bus bar 17, so that irradiation energy for melting can be reduced. Further, since the paint 21 is merely applied, the cost is lower than that of plating or the like, and the coating can be easily and quickly applied only to a necessary portion.

The thickness T2 of the bent leg 17b is
The tab terminal 17b need not be thinner than the plate thickness T1 (T2 = T1).

FIG. 5 shows a laser welding structure according to a fifth embodiment. As shown in FIG. 5B, the tab terminal 17a is
A tab terminal 17a, a bent leg 17b, and positioning projections 17h,..., 17h at both ends and a front end of the bent leg 17b are continuously punched out in a deployed state from the hoop material 6 or the like (see FIG. 9), thereby forming a valley fold. The tab terminal 17a is bent upward at 90 degrees along the line d. After that, each positioning protrusion 17h
Is bent at 90 degrees downward at the mountain fold line f, and the connecting portion 17e is cut at the cutting line e.

The tab terminal 17a formed as described above
A positioning hole 17i corresponding to each positioning projection 17h of the bent leg 17b is formed in the bus bar 17 to which the bent leg 17b is applied.

Then, the bent leg portion 1 of the tab terminal 17a
The positioning projections 17h of the bent legs 17b are inserted into the positioning holes 17i of the bus bar 17, respectively, and engaged with the bus bar 17 while applying 7b to the bus bar 17 from above.

As described above, the alignment of the tab terminals 17a is automatically corrected only by inserting the positioning projections 17h of the bent legs 17b of the tab terminals 17a into the positioning holes 17i of the pattern portions of the bus bar 17, so that the laser The man-hour for assembling the tab terminal 17a for welding is reduced, and the insertion force of the connector or the like is reduced by correcting the alignment.

FIG. 6 shows a laser welding structure according to a sixth embodiment. As shown in FIG. 6B, the tab terminal 17a is
Similarly to the fifth embodiment, the tab terminals 17a and the bent legs 17b are formed from the hoop member 6 and the like (see FIG. 9), and positioning projections 17h,.
7h are continuously punched in the developed state, and the tab terminal 17a is bent upward at 90 degrees at the valley fold line d. Thereafter, each positioning projection 17h is moved downward at the mountain fold line f by 90 degrees.
Then, the connecting portion 17e is cut along the cutting line e.

The tab terminal 17a formed as described above
A positioning hole 17i corresponding to each positioning projection 17h of the bent leg 17b is formed in the bus bar 17 to which the bent leg 17b is applied.

Then, the bent leg portion 1 of the tab terminal 17a
The positioning projections 17h of the bent legs 17b are inserted into the positioning holes 17i of the bus bar 17, respectively, and engaged with the bus bar 17 while applying 7b to the bus bar 17 from above.

[0062]

As is apparent from the above description, in the first and second aspects of the present invention, since the thickness of the bent leg portion is made smaller than the thickness of the tab terminal, the tab terminal is formed. In addition, while securing the board thickness for insertion connection of the female terminal,
By reducing only the thickness of the bent legs, the irradiation energy for melting can be reduced.

According to a third aspect of the present invention, the joint interface between the bent leg and the bus bar is directly irradiated with a laser beam using the welding hole of the bent leg, and the bent leg is fused to the bus bar by melting the joint interface. Weld to the pattern part, or use the hemispherical concave part of the bent leg part, irradiate the laser beam inside the hemispherical concave part, and melt the heat by the heat trapped in the hemispherical concave part to make the bent leg part to the busbar pattern part. Because it was made to weld, for the same reason as in claim 1 or 2,
Irradiation energy for melting can be reduced.

According to a fourth aspect of the present invention, a paint having a low reflectance applied to the bent legs is used, and a laser beam is applied to the paint-coated surface to melt the paint-coated surface so that the bent legs are formed on the bus bar pattern. Since the welding is performed, the irradiation energy for melting can be reduced for the same reason as the first or second aspect.

According to a fifth aspect of the present invention, the alignment of the tab terminals is automatically corrected only by inserting the positioning protrusions of the bent legs of the tab terminals into the positioning holes of the pattern portion of the bus bar. And the insertion force of the connector and the like can be reduced by correcting the alignment.

[Brief description of the drawings]

FIG. 1 is a laser welding structure according to a first embodiment of the present invention, in which (A) is a perspective view in which a tab terminal is laser-welded to a bus bar, (B) is a side sectional view, and (C) is a developed perspective view of the tab terminal. FIG.

FIG. 2 is a laser welding structure according to a second embodiment,
(A) is a perspective view in which a tab terminal is laser-welded to a bus bar,
(B) is an exploded perspective view of the tab terminal.

FIG. 3 is a laser welding structure according to a third embodiment,
(A) and (B) are perspective views of a tab terminal, respectively, (C)
(D) is a side sectional view, respectively.

FIG. 4 is a laser welding structure according to a fourth embodiment,
(A) and (B) are perspective views of a tab terminal, respectively.

FIG. 5 is a laser welding structure according to a fifth embodiment,
(A) is an exploded perspective view before a tab terminal is laser-welded to a bus bar, (B) is an exploded perspective view of the tab terminal.

FIG. 6 is a laser welding structure according to a sixth embodiment,
(A) is an exploded perspective view before a tab terminal is laser-welded to a bus bar, (B) is an exploded perspective view of the tab terminal.

FIG. 7 is a perspective view of a tab terminal integrally formed with a relay terminal.

FIG. 8 is a perspective view of a conventional bus bar.

FIG. 9 is an exploded perspective view of a conventional bus bar processing and assembling procedure.

FIGS. 10A and 10B are perspective views of a conventional laser welding structure for a crimp terminal or the like.

[Explanation of symbols]

 9 Electrical connection box 17 Bus bar 17a Tab terminal 17b Bend leg 17c Relay terminal 17f Welding hole 17g Hemispherical recess 17h Positioning protrusion 17i Positioning hole 18 Insulating plate 21 Paint LB Laser beam a Welding

Continued on the front page (72) Inventor Atsuhiko Fujii 1-7-10 Kikuzumi, Minami-ku, Nagoya City, Aichi Prefecture Inside Harness Research Institute, Inc. (72) Inventor Yoshifumi Saka 1-7-1, Kikuzumi, Minami-ku, Nagoya City, Aichi Prefecture No. Harness Research Institute, Inc. (72) Inventor Atsuhiro Togawa 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi Harness Research Institute, Inc. (56) References JP-A-9-108874 (JP, A JP-A-63-130290 (JP, A) JP-A-58-97489 (JP, A) JP-A-7-308790 (JP, A) JP-A-58-53118 (JP, A) 290945 (JP, A) JP-A-63-177987 (JP, A) JP-A-11-123585 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 26/00-26 / 22 H01R 4/02

Claims (5)

(57) [Claims] 1. A putter for a bus bar housed in an electric junction box.
Apply the tab terminal bent legs to the
Laser weld the bent leg of the tab terminal to the bar pattern.
A contact structure, half of the plate of the plate thickness required to connect plug female terminal
Tab terminals and bent legs are formed from thick flat conductors.
The tab terminal is folded over with the conductor,
Molded to the required thickness to insert and connect female terminals
The bent legs have half the thickness of the tab terminals.
Laser welded structure of the bus bar, characterized in that it is formed. 2. A busbar putter housed in an electric junction box.
Apply the tab terminal bent legs to the
Laser weld the bent leg of the tab terminal to the bar pattern.
The thickness required to insert and connect the female terminal
Tab terminals and bent legs from irregularly shaped conductors that are thinner than
Part is formed, and the tab terminal is inserted with the female terminal.
Is formed with the required thickness to connect only
The bent legs are formed to be thinner than the tab terminals.
Laser welded structure of the bus bar, characterized in that that. 3. Penetrating the bent leg to a welded body.
Or a hemispherical recess protruding toward the welded body.
The bus bar laser welding structure according to claim 1 or 2, wherein 4. The method according to claim 1, wherein the bending leg has a laser beam counter.
3. A coating material having a low emissivity is applied.
Laser welding structure of busbar. 5. A positioning projection is formed on the bent leg.
And at the same time,
A positioning hole is formed to insert and engage the positioning protrusion.
The laser welding structure for a bus bar according to claim 1 or 2, wherein: