JPH11297371A - Laser welding structure of bus bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a positional deviation of a terminal from being generated and improve weldability. SOLUTION: This structure in which a tab terminal 4a is abutted to a bus bar 4 accommodated in an electric connecting case, and the tab terminal 4a is laser-welded to the bus bar 4. A convex portion 4d is integrally formed to one of the bus bar 4 and the tab terminal 4a. The convex portion 4d is fitted to a concave portion 4b integrally formed to the other of the bus bar 4 and the tab terminal 4a, thereby setting the tab terminal 4a to the bus bar 4. In this setting state, the tab terminal 4a is laser-welded to the bus bar 4.

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.

[0002]

2. Description of the Related Art An electrical junction box used for branch connection of a wiring harness for automobiles to various electric components is provided with branch connection points concentrated at one place, and 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.

[0003] As an electric junction box as described above, FIG.
As shown in FIG. 2, there is a case in which a plurality of bus bars 4 are stacked and accommodated in an upper case 1 and a lower case 2 via an insulating plate 3.

In the case where the tab terminals 4a are integrally bent and formed on the bus bar 4, the wiring space is reduced only in the unfolded portion of the tab terminals 4a, and in order to secure the reduced wiring space. In this case, it is necessary to increase the number of stacked bus bars, so that the electric connection box is thickened.

For this reason, as shown in FIG. 12, the present applicant increases the wiring space by welding the laser beam LB to the bus bar 4 with the tab terminal 4a as a separate body, thereby increasing the stacking of the bus bar. A laser welding structure for a bus bar, in which the number of the electric junction boxes can be reduced by reducing the number, has been previously proposed (see Japanese Patent Application No. 9-138369).

[0006]

SUMMARY OF THE INVENTION The present invention relates to an improvement in the laser welding structure of a bus bar according to the proposal of the present applicant, and in particular, it is intended to prevent the displacement of the tab terminals and improve the weldability. An object of the present invention is to provide a laser welding structure for a bus bar.

[0007]

To solve the above-mentioned problems, a first aspect of the present invention is a structure in which a tab terminal is applied to a bus bar housed in an electric connection box, and the tab terminal is laser-welded to the bus bar. The tab terminal is set on the bus bar by fitting the projection integrally formed on one of the tab terminal and the bus bar into the recess integrally formed on the other, and setting the tab terminal on the bus bar in this setting state. An object of the present invention is to provide a bus bar laser welding structure characterized by laser welding.

According to the first aspect, the tab terminal can be accurately set at a predetermined position of the bus bar by, for example, fitting the projection integrally formed on the tab terminal into the recess integrally formed on the bus bar.

As described in claim 2, a notch into which the convex portion is integrally formed on both sides of the bent portion of the tab terminal and into which both sides of the bus bar are fitted. It is possible to form a configuration in which a concave portion having a shape of a circle is integrally formed.

According to a third aspect of the present invention, a cut-and-raised protruding portion is integrally formed at a central portion of the bent portion of the tab terminal, and a hole-shaped portion into which the protruding portion is fitted into a central portion of the bus bar. Are formed integrally with each other.

According to a fourth aspect of the present invention, there is provided a structure in which a tab terminal is applied to a bus bar housed in an electric connection box and the tab terminal is laser-welded to the bus bar. A laser welding structure for a bus bar, characterized in that the integrally formed barrel portion is wound around the other, the tab terminal is crimped to the bus bar and set, and the tab terminal is laser-welded to the bus bar in the crimp setting state. Things.

According to the fourth aspect, for example, the barrel portion integrally formed on the tab terminal is wound around the bus bar,
The tab terminal can be crimped to a predetermined position of the bus bar to accurately set the tab terminal.

According to a fifth aspect of the present invention, a falling barrel portion is integrally formed on both sides of the bent portion of the tab terminal, and the barrel portion can be wound around the bus bar.

According to a sixth aspect of the present invention, a notch-shaped recess into which the barrel is fitted is integrally formed on both sides of the bus bar, and the barrel is fitted with the barrel in the recess. It can be configured to be wound around a bus bar.

According to a seventh aspect of the present invention, the tab terminal may be configured such that a terminal portion is formed by folding a thin plate, and the barrel portion is wound around the bus bar while the barrel portion remains as a thin plate.

[0016]

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.

FIGS. 1 and 2 show a laser welding structure according to a first embodiment. At predetermined positions of the bus bar 4, notched concave portions 4b are integrally formed on both sides in the width direction.

The tab terminal 4a is not cut and raised from the bus bar 4 as in the prior art. Instead, the tab terminal 4a is formed as a separate body and a bent portion 4c is integrally formed at the lower end of the tab terminal 4a. Falling convex portions 4d are integrally formed on both sides in the width direction of the margin portion 4c. This convex part 4d
Is shaped to fit into the recess 4b from above.

When the lower surface of the bent portion 4c is brought into contact with the upper surface of the bus bar 4 while fitting each projection 4d of the tab terminal 4a into each concave portion 4b of the bus bar 4 from above, the tab terminal 4a has a length corresponding to the length of the bus bar 4. The direction is set in the field direction.

When the laser beam LB is applied to the margin 4c of the tab terminal 4a in this setting state, the margin of the margin 4c is laser-welded to the stub 4. In addition, you may perform laser welding a from the side at the overlapping part of each convex part 4d of the tab terminal 4a and both side surfaces of the bus bar 4.

In the laser welding structure of the first embodiment, the tab terminal 4a is accurately positioned at a predetermined position on the bus bar 4 by fitting the projection 4d integrally formed on the tab terminal 4a into the recess 4b integrally formed on the bus bar 4. Since the setting can be performed, the position shift of the tab terminal 4a can be prevented, the defect due to the position shift is reduced, and the quality is stabilized.

Further, the tab-shaped terminal 4a has a protruding portion 4 having a falling shape.
(d) Since the notch-shaped recesses 4b are only formed integrally with the bus bar 4, complicated and expensive setting equipment is not required. Further, since the convex portion 4d is fitted into the concave portion 4b, the tab terminal 4a becomes strong against lateral force,
It becomes difficult to peel off from the bus bar 4. The tab terminal 4a
A notch-shaped concave portion 4b may be formed integrally with the bus bar 4, and a rising convex portion 4d may be formed integrally with the bus bar 4. However, as in the present embodiment, the falling convex portion 4b is formed on the tab terminal 4a.
By forming d, there is no need for a cut-and-raised portion for the raised protrusion 4 d in the bus bar 4, so that there is an advantage that a dead space for cutting and raising in the bus bar 4 is not required.

FIGS. 3 and 4 show a laser welding structure according to a second embodiment. Hole-shaped concave portions 4b are integrally formed at predetermined positions of the bus bar 4 in front and rear in the longitudinal direction.

Further, the bending margin 4 of the separate tab terminal 4a is provided.
A downwardly raised raised portion 4d is integrally formed before and after in the longitudinal direction of c. The projection 4d is shaped to fit into the recess 4b from above.

Then, similarly to the first embodiment, when the lower surface of the bent portion 4c is brought into contact with the upper surface of the bus bar 4 while fitting each convex portion 4d of the tab terminal 4a into each concave portion 4b of the bus bar 4 from above, the bus bar 4 The tab terminal 4a is positioned and set in the length direction and the width direction of the tab terminal 4. When the laser beam LB is irradiated to the margin 4c of the tab terminal 4a in this setting state, the margin 4c is laser-welded to the bus bar 4. a.

In the laser welding structure of the second embodiment, the first
In addition to the functions and effects of the embodiment, since no cut-and-raised portion is required in the bus bar 4, a dead space for the cut-and-raise in the bus bar 4 is not required, and a dead space for the fall is also provided in the tab terminal 4a. Since it becomes unnecessary,
Material yield is improved.

FIGS. 5 and 6 show a laser welding structure according to a third embodiment. Falling barrel portions 4e are integrally formed on both sides in the width direction of the bent margin portion 4c of the separate tab terminal 4a. The two barrel portions 4e are shaped to fit into the bus bar 4 on both sides from above.

Then, the lower surface of the bent portion 4c is applied to the upper surface of the bus bar 4 while fitting the respective barrel portions 4e of the tab terminals 4a on both sides of the bus bar 4 from above, and then the two barrel portions 4e are pressed from both sides of the bus bar 4. When the tab terminal 4a is wound around the lower surface, the tab terminal 4a is positioned and set in the length direction and the width direction on the bus bar 4, and in this setting state, the laser beam L is applied to the margin 4c of the tab terminal 4a.
When B is applied, the margin 4c is laser-welded to the bus bar 4. In addition, you may perform laser welding a from the side to each barrel part 4e of the tab terminal 4a and both side surfaces of the bus bar 4.

In the laser welding structure according to the third embodiment, the barrel terminal 4e integrally formed with the tab terminal 4a is wound around the bus bar 4, so that the tab terminal 4a can be crimped to a predetermined position of the bus bar 4 and set accurately. Therefore, the displacement of the tab terminal 4a can be prevented, the defects due to the displacement can be reduced, and the quality can be stabilized. Also,
By winding and tightening the barrel portion 4e, the tab terminal 4a can be crimped to the bus bar 4 for setting, so that the weldability is improved and the quality is stabilized in this respect as well.
Further, since the barrel portion 4e is only formed integrally with either the tab terminal 4a or the bus bar 4, complicated and expensive equipment for crimping and setting is not required. Furthermore, since the barrel portion 4e is wound around the bus bar 4, the tab terminal 4
a becomes strong against the lateral force, and it becomes difficult to peel off from the bus bar 4.

The barrel 4e may be integrally formed on both sides of the bus bar 4 without integrally forming the barrel 4e with the margin 4c of the tab terminal 4a, as in the present embodiment. By forming the falling barrel portion 4e on the tab terminal 4a, a cut-and-raised portion for the rising barrel portion 4e is not required in the bus bar 4, so that a dead space for the cut and raised in the bus bar 4 is eliminated. There is an advantage that it becomes unnecessary.

FIGS. 7 and 8 show a laser welding structure according to a fourth embodiment. At predetermined positions of the bus bar 4, notched concave portions 4b are integrally formed on both sides in the width direction.

A falling barrel portion 4e is integrally formed on both sides in the width direction of the bent margin portion 4c of the separate tab terminal 4a. The two barrel portions 4e are provided with the concave portions 4b of the bus bar 4.
Into a shape from above.

Then, while fitting each barrel portion 4e of the tab terminal 4a into the recess 4b of the bus bar 4 from above, the lower surface of the bending portion 4c is brought into contact with the upper surface of the bus bar 4, and then both barrel portions 4e are connected to the recesses of the bus bar 4. 4b, the tab terminals 4a are positioned and set on the bus bar 4 in the length direction and the width direction, and in this setting state, the bent portions 4c of the tab terminals 4a are set.
Is irradiated with the laser beam LB, the bending margin 4 c is laser-welded to the bus bar 4.

In the laser welding structure of the fourth embodiment, the third
In addition to the functions and effects of the embodiment, by fitting the barrel portion 4 e integrally formed with the tab terminal 4 a into the recess 4 b of the bus bar 4, the tab terminal 4 a can be accurately set at a predetermined position of the bus bar 4, and at the same time, the bus bar 4 The tab terminal 4a can be set by crimping.

FIGS. 9 and 10 show a laser welding structure according to a fifth embodiment. The separate tab terminal 4a is formed by folding a thin plate having approximately half the normal thickness (same as the thickness of the bus bar 4) into two sheets to form a terminal portion 4f, and a bending portion 4c.
Falling barrels 4 on both sides in the width direction of the thin plate
e is integrally formed. The two barrel portions 4e are shaped to fit into the bus bar 4 on both sides from above.

Then, while fitting the respective barrel portions 4e of the tab terminals 4a on both sides of the bus bar 4 from above, the lower surface of the bending portion 4c is applied to the upper surface of the bus bar 4, and then both barrel portions 4e are placed on both sides of the bus bar 4. When the tab terminal 4a is wound around the lower surface, the tab terminal 4a is positioned and set in the length direction and the width direction on the bus bar 4, and in this setting state, the laser beam L is applied to the margin 4c of the tab terminal 4a.
When B is applied, the margin 4c is laser-welded to the bus bar 4.

In the laser welding structure of the fifth embodiment, the third
In addition to the operation and effect of the embodiment, since the barrel portion 4e remains a thin plate, laser welding with small power becomes possible and a stable welding state as compared with the case where the busbar 4 has the same thickness. Can be maintained.

When the tab terminals 4a are welded to the bus bar 4, if conventional resistance welding is used, a large jig is required for each bus bar to sandwich the bus bar between the electrodes.
Processing man-hours and equipment become expensive, which is not suitable for mass production. 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. In addition, the tab terminal 4a can be welded to the bus bar 4 and the welding time per spot is short, so that mass productivity is good. Further, since the laser beam LB has a small beam diameter, the bus bar 4 and the tab terminal 4a are connected to each other. There is an advantage that the pitch can be narrowed, and the degree of freedom in design wiring is improved.

[0040] 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.

[0041]

As is clear from the above description, the laser welding structure for a bus bar according to the first aspect of the present invention can be realized by fitting a projection integrally formed on a tab terminal into a recess integrally formed on a bus bar, for example. Since the tab terminals can be accurately set at predetermined positions of the bus bar, displacement of the tab terminals can be prevented, defects due to the displacement can be reduced, and quality can be stabilized. Further, since only the projection is formed integrally with one of the tab terminal and the bus bar and the depression is formed integrally with the other, no complicated and expensive setting equipment is required. Further, since the convex portion is fitted into the concave portion, the tab terminal becomes strong against a lateral force, and is less likely to be separated from the bus bar.

According to a second aspect of the present invention, when the protrusions are integrally formed on both sides of the bent portion of the tab terminal and the recesses are integrally formed on both sides of the bus bar, a cut-and-raised portion for the protrusion is not required in the bus bar. Therefore, a dead space for cutting and raising the bus bar is not required.

According to a third aspect of the present invention, when the convex portion is integrally formed at the center of the bent portion of the tab terminal and the concave portion is integrally formed at the center of the bus bar, the bus bar does not need a cut-and-raised portion. Since no dead space for cutting and raising is required, and no dead space for falling is required for the tab terminal, the yield of material is improved.

According to the laser welding structure for a bus bar according to the fourth aspect of the present invention, for example, a barrel portion integrally formed with the tab terminal is wound around the bus bar, whereby the tab terminal is crimped to a predetermined position on the bus bar to accurately press the tab terminal. Therefore, it is possible to prevent the tab terminals from being displaced, thereby reducing defects due to the displacement and stabilizing the quality. In addition, since the tab terminal can be crimped to the bus bar and set by winding the barrel portion, the weldability is improved and the quality is stabilized in this respect as well. Furthermore, since the barrel portion is only formed integrally with either the tab terminal or the bus bar, complicated and expensive crimping and setting equipment is not required. Furthermore, since the barrel portion is wound around the bus bar, the tab terminal is strong against lateral force, and is less likely to be separated from the bus bar.

According to a fifth aspect of the present invention, a falling barrel portion is integrally formed on both sides of the bent portion of the tab terminal, and when this barrel portion is wound around a bus bar, the bus bar is cut and raised for the barrel portion. Since no part is required, a dead space for cutting and raising the bus bar is not required.

According to a sixth aspect of the present invention, a concave portion is integrally formed on both sides of the bus bar, and when the barrel portion is wound around the bus bar with the barrel portion fitted in the concave portion, the barrel portion integrally formed on the tab terminal is formed. By fitting the tab terminal into a predetermined position of the bus bar by fitting the tab terminal into the recess of the bus bar, the tab terminal can be crimped onto the bus bar and set.

When the thin plate is folded to form the terminal portion of the tab terminal, and the barrel portion of the tab terminal is wound around the bus bar while the barrel portion remains thin, the barrel portion remains thin. Compared with the case where the plate thickness is equivalent to that of the bus bar, laser welding with small power becomes possible and a stable welding state can be maintained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a laser welding structure according to a first embodiment of the present invention before a tab terminal is laser-welded to a bus bar.

FIG. 2 is an enlarged sectional view taken along line AA of FIG. 1 after laser welding.

FIG. 3 is a perspective view of a laser welding structure according to a second embodiment before a tab terminal is laser-welded to a bus bar.

FIG. 4 is an enlarged sectional view taken along line BB of FIG. 3 after laser welding.

FIG. 5 is a laser welding structure according to a third embodiment,
(A) is a perspective view after a tab terminal is laser-welded to the bus bar, (b) is an enlarged sectional view taken along line CC of (a).

FIG. 6 is a perspective view before a tab terminal is laser-welded to the bus bar of FIG. 5;

FIG. 7 is a perspective view of a laser welding structure according to a fourth embodiment before a tab terminal is laser-welded to a bus bar.

FIG. 8 is an enlarged sectional view taken along line DD of FIG. 7 after laser welding.

FIG. 9 is a perspective view after a tab terminal is laser-welded to a bus bar of a laser-welded structure according to a fifth embodiment.

FIG. 10 is a perspective view before a tab terminal is laser-welded to the bus bar of FIG. 9;

FIG. 11 is an exploded view of a conventional electric junction box.

FIG. 12 is a side view of a prior art bus bar laser welding structure.

[Explanation of symbols]

 9 Electrical connection box 4 Bus bar 4a Tab terminal 4b Concave part 4c Bend margin 4d Convex part 4e Barrel part 4f Terminal part LB Laser beam a Welding

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01R 4/58 H01R 4/58 C (72) Inventor Yoshifumi Saka 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi Pref. In-house (72) Inventor Yu Araki 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi Harness Research Institute, Inc.

Claims (7)

[Claims] 1. A structure in which a tab terminal is applied to a bus bar housed in an electric junction box and the tab terminal is laser-welded to the bus bar, and wherein the projection is formed integrally with one of the tab terminal and the bus bar. A tab terminal is set on the bus bar by fitting the tab terminal into a recess formed integrally with the other, and the tab terminal is laser-welded to the bus bar in this setting state. 2. A falling convex portion is integrally formed on both sides of a bent margin portion of the tab terminal, and a cutout concave portion into which the convex portion is fitted is integrally formed on both sides of the bus bar. The laser welding structure for a bus bar according to claim 1, wherein the laser welding structure is formed. 3. A cut-and-raised convex portion is integrally formed at a central portion of a bent margin portion of the tab terminal, and a hole-shaped concave portion into which the convex portion is fitted is integrally formed at a central portion of the bus bar. The laser welding structure for a bus bar according to claim 1, wherein: 4. A structure in which a tab terminal is applied to a bus bar housed in an electric junction box and the tab terminal is laser-welded to the bus bar, and a barrel portion integrally formed on one of the tab terminal and the bus bar. A tab terminal is crimped to the bus bar, and the tab terminal is crimped to the bus bar for setting. In this crimp setting state, the tab terminal is laser-welded to the bus bar. 5. The laser welding structure for a bus bar according to claim 4, wherein a falling barrel portion is integrally formed on both sides of the bent margin portion of the tab terminal, and the barrel portion is wound around the bus bar. 6. A notch-shaped concave portion into which the barrel portion is fitted on both sides of the bus bar, and the barrel portion is wound around the bus bar with the barrel portion fitted in the concave portion. Item 6. A laser welding structure for a bus bar according to Item 5. 7. The laser welding structure for a bus bar according to claim 5, wherein the tab terminal is formed by folding a thin plate to form a terminal portion, and is wound around the bus bar while the barrel portion remains thin. .