JPH10334959A - Laser welding structure of bus bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably enhance the alignment accuracy and the jointing strength of a tab terminal jointed with a bus bar by welding. SOLUTION: A press-fitting guide portion 18g is formed on bus bars 17A to 17C-arranged insulation plates 18A, 18B. Tab terminals 17D to 17F lower ends 17f are press fitted into the pattern portion ends 17e of the bus bars 17A to 17C as guiding the tab terminals 17D to 17F by the press fitting guide portion 18b. Thereafter, the lower end portions 17f of the tab terminal 17D to 17F and the pattern portion end part 17e of the bus bar 17A to 17C are welded by a laser beam LB from an oblique direction.

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 accommodated in an electric junction box, and more particularly to a laser welding structure capable of stably improving the alignment accuracy and joining strength of a tab terminal to be welded to a bus bar. It is.

[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. (Japanese Patent Application No. 2-103) has been proposed.
No. 8786).

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 this laser welding structure, basically, tab terminals are not cut and raised in the vertical direction from the bus bar pattern portion, but as shown in FIG.
A separate tab terminal 7a is applied to the pattern portion of the bus bar 7 to irradiate a laser beam LB, and the tab terminal 7a and the pattern portion of the bus bar 7 are fused and welded. Since no dead space is required in the pattern portion of the bus bar 7 to cut and raise the tab terminals 7a, the bus bar 7 can be reduced in size and density by increasing the pattern portion in this dead space. .

[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 busbar housed in an electric junction box and welded to the busbar. An object of the present invention is to provide a bus bar laser welding structure capable of stably improving the alignment accuracy and joining strength of tab terminals.

[0017]

According to a first aspect of the present invention, there is provided a laser welding structure for a bus bar housed in an electric junction box, wherein an insulating plate on which the bus bar is disposed is provided with an insulating plate having the bus bar. At the end of the pattern portion, a press-in guide portion capable of press-fitting the lower end of the tab terminal from a right angle direction is formed, and the lower end of the tab terminal and the bus bar are pressed by the press-in guide portion and press-fitted into the end of the bus bar pattern portion. An object of the present invention is to provide a laser welding structure of a bus bar, wherein a laser beam is welded to an end of a pattern portion from an oblique direction by a laser beam.

According to the present invention, the lower end of the tab terminal is press-fitted into the end of the pattern portion of the bus bar while the tab terminal is guided by the press-fitting guide portion of the insulating plate, and then joined by welding with a laser beam. Also, with the lower end of the tab terminal pressed into the end of the bus bar pattern, the laser beam is irradiated from an oblique direction to the joint interface between the end of the bus bar pattern and the lower end of the tab terminal for welding. Join.

According to a second aspect of the present invention, if the bent portion for expanding the press-fitting surface is formed at the end of the pattern portion of the bus bar, the press-fitting becomes strong.

Furthermore, if the relay terminal and the like are formed integrally with the tab terminal as described in claim 3, a separate relay terminal and the like become unnecessary.

[0021]

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 of the prior art are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 2, the first-layer insulating plate 18A
The first bus bar 17A is arranged on the upper surface of the
8A and the upper surface of the second layer insulating plate 18B.
A bus bar 17B is arranged, and a third bus bar 17C is arranged on the lower surface of the insulating plate 18B. The insulating plate 1
8A, 18B, ... and bus bars 17A, 17B, 17
C,... May be further stacked in multiple layers.

At the end portion 17d of the pattern portion of each of the bus bars 17A to 17C, bent portions 17e,... Which are bent upward at right angles with the same size (for example, several mm) are formed.

As shown in FIG. 3, the tab terminals 17D, 17
E and 17F are not cut and raised integrally from the pattern portion as in the conventional bus bar, but are separately provided at the lower ends of the tab terminals 17D to 17F as lower end legs 17f extending straight downward. Are formed respectively. The lower end legs 17f of each of the tab terminals 17D to 17F have a length L.
1, L2, L3 are different from each other in a stepwise manner, and the tab terminals 1
The length L1 of the lower end leg 17f of 7D is set to be the shortest, and the length L3 of the lower end leg 17f of the tab terminal 17F is set to be the longest (L1 <L2 <L3).

On the upper surface of the first layer insulating plate 18A, there is formed a first rising portion 18a which rises upward along the outer end surface of the bent portion 17e of the pattern portion of the first bus bar 17A. From the lower surface of the plate 18A, there is formed a second rising portion 18b which rises upward along the outer end surface of the bent leg portion 17e of the pattern portion of the second bus bar 17B via the slit 18d, and furthermore, the first layer insulating plate 18A From the lower surface of the third bus bar 17C, the slit 18f of the second-layer insulating plate 18B and the slit 18e of the first-layer insulating plate 18A are spaced upward along the outer end surface of the bent leg 17e of the pattern portion of the third bus bar 17C. A third rising portion 18c that rises is formed.

The height L1 of the first rising portion 18a is
The length L1 of the lower end leg 17f of the first bus bar 17D is set to be the same as the length L1, and the height L2 of the second rising portion 18b is
The length L2 of the lower leg portion 17f of the bus bar 17E is set to be the same as the length L2, and the height L2 of the third rising portion 18c is set to be the same as the length L3 of the lower leg portion 17f of the third bus bar 17F. On the inner surfaces of the rising portions 18a to 18c, concave press-fitting guide portions 18g for inserting the lower end legs 17f of each of the bus bars 17D to 17F at right angles from above.
Are formed respectively.

When the lower ends 17f of the tab terminals 17D to 17F are inserted into the press fitting guides 18g from above, the lengths L1 to L3 of the lower legs 17f and the press fitting guides 18g, Are set to be the same as the heights L1 to L3, the insertion strokes are different.
As shown in (A), the height positions of the tab terminals 17D to 17F after insertion are the same.

By this insertion, each of the tab terminals 17D to 17D
Are connected to the bus bars 17A to 17C.
The outer end faces of the bent portions 17e,.
g,... are pressed into the bent portions 17e,
... come into contact with each other in a press-fitted state.

With respect to the tab terminal 17D, a laser beam is applied obliquely from above to the joint interface between the outer end surface of the bent portion 17e of the pattern portion of the bus bar 17A and the outer end surface of the lower leg portion 17f of the tab terminal 17D. When the LB is irradiated, the irradiation melts the bonding interface and welds the tab terminal 17D to the bus bar 17A as shown in detail in FIG. 1B.

With respect to the tab terminal 17E, the slit 18d is inserted obliquely upward through a joint interface between the outer end surface of the bent portion 17e of the pattern portion of the bus bar 17B and the outer end surface of the lower leg 17f of the tab terminal 17E. When the laser beam LB is irradiated from the above, the joint interface is similarly melted by this irradiation, and the tab terminal 17E is welded to the bus bar 17B.

With respect to the tab terminal 17F, a slit 18e, 18f is formed obliquely through a joint interface between the outer end surface of the bent portion 17e of the pattern portion of the bus bar 17C and the outer end surface of the lower leg portion 17f of the tab terminal 17F. When the laser beam LB is irradiated from above, the joint interface is similarly melted by this irradiation, and the tab terminal 1 is connected to the bus bar 17C.
7F is welded.

As described above, the bus bars 17A to 17C are guided by the press-fitting guide portions 18g of the rising portions 18a, 18c of the insulating plate 18A to guide the lower end legs 17f of the tab terminals 17D to 17F, respectively. Are press-fitted into the bent portions 17e,.
By welding and joining at B, the tab terminals 17D to 17F are accurately positioned by press-fitting, so that alignment accuracy is improved.

The bus bar 17A is pressed with the lower leg portions 17f of the tab terminals 17D to 17F into the bent portions 17e of the pattern portions of the bus bars 17A to 17C.
-17C and the lower end legs 17f of the tab terminals 17D-17F are welded by irradiating the laser beam LB from an obliquely upper direction to the bus bar 17A. .. And the lower end legs 17f of the tab terminals 17D to 17F are reliably melted, so that the bonding strength is stably increased.

The bent portions 17e,... Of the pattern portions of the bus bars 17A to 17C expand the press-fit surface, so that the press-fit is strengthened and the alignment accuracy is further improved.

As shown in FIG. 6, the tab terminals 17D
When the relay terminal 17c is formed integrally with the relay terminals 17F to 17F, a separate relay terminal is not required.

Tab terminals 1 are connected to the bus bars 17A to 17C.
When welding 7D to 17F, if the conventional resistance welding is used, a large jig is attached to each tab terminal 17D to sandwich each bent leg 17e,... And the lower leg 17f,.
Since it is necessary every 17F, the number of processing steps and equipment become expensive, which is not suitable for mass production. Further, in the case of conventional arc welding, in each of the tab terminals 17D to 17F, since the gap between the tab terminals and other tab terminals is narrow, it is necessary to insulate or widen the gap, so that the density cannot be increased. Further, in the ultrasonic welding, partial plating is necessary because welding cannot be performed at the portions where the tab terminals 17D to 17F have plating.

On the other hand, in the case of the laser welding according to the present invention, the laser beam LB is not in contact with the above-described resistance welding, arc welding, ultrasonic welding, etc. The tab terminals 17D to 17F can be welded to each other, and the mass production is good because the welding time per one place is short. In addition, since the laser beam LB has a small beam diameter, each of the tab terminals 17D to 17F can be welded. There is an advantage that the pitch can be narrowed and the degree of freedom in designing wiring is improved.

[0038] Of 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.

In the above embodiment, the press-fitting guide portions 18g,... Of the rising portions 18a,..., 18c of the insulating plate 18A are formed in a concave shape, but as shown in FIG. If formed in a guide rail shape, each tab terminal 17
The lower leg portions 17f of D to 17F are securely held.

The tab terminal 17E (tab terminal 17)
F), the laser beam LB is irradiated obliquely from above through the slit 18d. However, as shown in FIG. 5A, when the insulating plate 18B is not laminated, the laser beam LB is irradiated from below. Straightly, the outer end face of the bent portion 17e of the pattern portion of the bus bar 17A and the tab terminal 17
The laser beam LB is applied to the joint interface between the lower end leg 17f and the outer end surface of the lower end leg 17f of the lower terminal leg 17f, and the tab terminal 17 is connected to the bus bar 17B.
E may be welded.

Further, as shown in FIG. 5 (B), the bent portion 17e of the pattern portion is bent downward with respect to the bus bar 17A, and the outer end surface of the bent portion 17e and the lower end leg 17f of the tab terminal 17D. The laser beam LB may be applied to the joining interface between the outer end surface of the bus bar 17A and the tab terminal 17D to be welded to the bus bar 17A.

[0042]

As is clear from the above description, the laser welding structure of the bus bar according to the present invention is such that the tab terminal is guided by the press-fitting guide portion of the insulating plate, and the lower end of the tab terminal is connected to the end of the bus bar pattern portion. After press-fitting into the part and positioning accurately, it was welded with a laser beam and joined.
The alignment accuracy of the tab terminals is improved and the quality is stabilized.

Further, in a state where the lower end of the tab terminal is pressed into the end of the bus bar pattern portion, a laser beam can be radiated to the joining interface from an oblique direction to perform welding and joining, so that the end of the bus bar pattern portion and the tab terminal can be joined. Is reliably melted, so that the bonding strength is stably increased.

When a bent portion for expanding the press-fitting surface is formed at the end of the pattern portion of the bus bar as in claim 2, the press-fitting is strengthened and the alignment accuracy is further improved.

According to a third aspect of the present invention, the relay terminal and the like are integrally formed with the tab terminal, and a separate relay terminal and the like become unnecessary, so that the number of parts can be reduced.

[Brief description of the drawings]

FIG. 1 is a laser welding structure of a bus bar according to the present invention, in which (A) is a side sectional view in which a tab terminal is welded to a bus bar, and (B) is an enlarged welding state of a bent portion of the bus bar and a lower end leg of the tab terminal. It is sectional drawing.

FIG. 2 is a side sectional view before a tab terminal is welded to a bus bar.

3 (A), 3 (B), and 3 (C) respectively show P in FIG.
FIG. 4 is a sectional view taken along lines -P, QQ, and RR.

FIG. 4 is a plan view of a modified example of a press-fit guide portion at a rising portion of an insulating plate.

FIGS. 5A and 5B are side cross-sectional views of modifications of a welding structure of a bent portion of a bus bar, respectively.

FIG. 6 is a perspective view of a tab terminal formed integrally with a relay terminal.

FIG. 7 is a perspective view of a prior art tab terminal welding structure.

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 (A, B, C) Bus bar 17 (D, E, F) Tab terminal 17e Bending portion 17f Lower leg portion 18 (A, B) Insulating plates 18a to 18c Rising portion 18g Press-fit gad portion LB Laser beam a welding

Claims (3)

[Claims] 1. A laser welding structure for a bus bar housed in an electric junction box, wherein a press-fitting guide portion capable of press-fitting a lower end of a tab terminal to an end of a pattern portion of the bus bar from an orthogonal direction to an insulating plate on which the bus bar is arranged. The lower end of the tab terminal pressed into the end of the busbar pattern portion guided by the press-fitting guide portion and the end of the busbar pattern portion are welded obliquely with a laser beam. Laser welding structure of busbar. 2. The laser welding structure for a bus bar according to claim 1, wherein a bent portion for expanding a press-fit surface is formed at an end of the pattern portion of the bus bar. 3. The laser welding structure for a bus bar according to claim 1, wherein a relay terminal or the like is integrally formed with the tab terminal.