JP3417835B2 - Laser welding method for busbar - 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 method most suitable for a bus bar accommodated in an electric connection box.

[0002]

2. Description of the Related Art An electrical junction box used for branching and connecting a wire harness for an automobile to various electric components has branch connecting points concentrated at one place to branch and connect wiring reasonably and economically. With the increasing density of wire harnesses, various types have been developed depending on the vehicle type or application.

As an electric connection box as described above, as shown in FIG. 7, there is a case in which a plurality of bus bars 4 are stacked and housed inside an upper case 1 and a lower case 2 with an insulating plate 3 interposed therebetween. .

When the tab terminal 4a is integrally formed on the bus bar 4 by bending, the wiring space is reduced only in the unfolded portion of the tab terminal 4a, and the reduced wiring space is ensured. Therefore, it is necessary to increase the number of laminated bus bars, and thus the electrical junction box becomes thicker.

Therefore, as shown in FIG. 8, the applicant of the present invention separates the tab terminal 4a and performs laser welding a with the laser beam LB on the bus bar 4 to increase the wiring space and to increase the wiring space of the bus bar. A laser welding structure for a bus bar was proposed in advance, which enables the electrical junction box to be made thinner by reducing the number of layers (Japanese Patent Application No. 9-13836).
(See No. 9).

As a method of laser welding the tab terminal 4a to the bus bar 4, as shown in FIG. 6, a traverse cylinder 5 traverses and a hoisting motor 6 swivels to support the hoisting cylinder 7 so that it can be lifted and lowered. The tab terminal 4a is clamped by the chuck 8 and the bending margin portion 4b of the tab terminal 4a is held.
Is applied to the upper surface of the bus bar 4, the laser beam LB from the laser head 9 supported by the lifting cylinder 8 and the like.
Is applied to the bend allowance 4b so that the bend allowance 4b of the tab terminal 4a is laser-welded to the bus bar 4.

[0007]

However, since the bending margin portion 4b of the tab terminal 4a held by the chuck 8 of the elevating cylinder 7 is applied to the upper surface of the bus bar 4, the upper surface of the bus bar 4 and the tab terminal are prevented. Bending margin part 4 of 4a
Since the close contact with b is difficult to be uniform, there is a possibility that laser welding defects such as welding loss, discontinuity, and cracks may occur.

Further, since the lifting cylinder 7, the traverse cylinder 5, the turning motor 6 and the like are controlled in order to position the bending allowance 4b of the tab terminal 4a at a predetermined position of the bus bar 4, the positioning accuracy is very poor. Fine adjustment was required for each tab terminal.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a laser welding method for a bus bar, which has accurate positioning accuracy and is less likely to cause laser welding defects.

[0010]

In order to solve the above-mentioned problems, the first aspect of the present invention is a method for laser-welding a tab terminal to a bus bar housed in an electric junction box, wherein the tab terminal has a bending margin. Insert the small-diameter lower end of the lowered positioning presser pin into the positioning hole formed on the bus bar and the positioning hole formed on the bus bar to position the bend margin of the tab terminal on the bus bar and move it downward. A laser welding method for a bus bar, characterized in that the bending margin portion is laser-welded to the bus bar in a state where the bending margin portion is pressed against the bus bar by the large-diameter stepped portion of the pressing pin. The tab terminal is manufactured in a continuous terminal state in which adjacent bending margin portions are connected in series by a carrier portion, and after bending each of the bending margin portions of each tab terminal to a corresponding bus bar by laser welding, the carrier portion is It can be configured to be cut (claim 2).

A third aspect of the present invention is a method for laser-welding a tab terminal to a bus bar housed in an electrical junction box,
The tab terminal is manufactured in a continuous terminal state in which adjacent bending margin portions are connected in series by the carrier portion, and the tab terminal moves downward to the positioning hole formed in the carrier portion and the positioning hole formed in the bus bar. Insert the small-diameter lower end of the positioning presser pin into the bus bar to position the carrier part of the tab terminal, and hold the carrier part against the bus bar with the large diameter step of the pressed-down presser pin. The present invention provides a method for laser welding a bus bar, characterized in that the bending margin portion is laser-welded to the bus bar. The carrier portions may be cut after laser welding the bending margin portions of the tab terminals to the corresponding bus bars, respectively.

[0012]

According to the invention of claim 1, the small-diameter lower end portion of the lowered positioning and pressing pin is inserted into the positioning hole of the bus bar through the positioning hole of the bending allowance portion of the tab terminal. Accurate positioning accuracy of tab terminals. Also, laser welding the bend allowance to the bus bar while holding the bend allowance of the tab terminal against the bus bar with the large diameter step of the positioning press pin that was moved down, The adhesion with the bending margin portion becomes uniform, and laser welding defects such as welding loss, non-conductivity, and cracks are less likely to occur. According to claim 2 which depends on claim 1, the tab terminal is manufactured in a continuous terminal state,
If the carrier portion is cut after laser welding the bent portion of the tab terminal to the bus bar, a series of steps such as feeding the tab terminal, positioning, laser welding, and cutting the carrier portion can be automated.

According to a third aspect of the present invention, the positioning holes are formed in the bending allowance portion of the tab terminal, whereas the positioning holes are formed in the carrier portion of the tab terminal. . By inserting the small-diameter lower end portion of the lowered positioning presser pin into the positioning hole of the bus bar through the positioning hole of the carrier portion of the tab terminal, the positioning accuracy of the tab terminal becomes accurate. Also, while the carrier part of the tab terminal is pressed against the bus bar by the large-diameter stepped part of the positioning presser pin that was moved down, the bending margin is laser-welded to the bus bar, and the upper surface of the bus bar and the tab terminal are bent. The uniform contact with the margin portion makes it possible to prevent laser welding defects such as welding loss, discontinuity, and cracks. According to claim 4 which depends on claim 3, when the carrier portion is cut after the bending margin portion of the tab terminal is laser-welded to the bus bar, the tab terminal is supplied, positioned, laser-welded, and the carrier portion is cut. It becomes possible to automate a series of steps such as.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that parts having the same configurations and functions as those of the conventional technique are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, the tab terminal 4a is
The expanded state shown by the two-dot chain line d is bent and formed into an L-shape to form the bending margin portion 4b. The tab terminal 4a is manufactured in a continuous terminal state in which the adjacent bending margin portions 4b are connected in series by the carrier portion 4c.

Positioning holes 4d are formed in the bending allowances 4b of each tab terminal 4a in the continuous terminal state. Positioning holes 4e are also formed in each carrier portion 4c as needed.

As shown in FIG. 2, the bus bar 4 includes:
The bending margin portion 4b is provided at a position where the tab terminal 4a is laser-welded.
A positioning hole 4f having the same diameter as the positioning hole 4d is formed. When the positioning hole 4e is formed in the carrier portion 4c, a positioning hole having the same diameter as the positioning hole 4e of the carrier portion 4c is formed at an appropriate position of the bus bar 4 corresponding to the position where the tab terminal 4a is laser-welded. To do.

As shown in FIG. 3 (a), the positioning hole 4d is formed only in the bending allowance portion 4b of the tab terminal 4a, or as shown in FIG. 3 (b), the bending allowance portion 4b is formed. It is also possible to form the positioning hole 4e only in the carrier portion 4c.

Then, as shown in FIG. 4, the tab terminals 4a in the continuous terminal state are automatically supplied to the predetermined tab terminals 4a.
Bending margins 4b (two in this example) are respectively applied to the upper surfaces of the bus bars 4 placed on the welding table 11, and in this state, the positioning pressing pin 10 is moved downward to make the small diameter lower end 10a. Is inserted into the positioning hole 4f of the bus bar 4 from the positioning hole 4d of the bending margin portion 4b of the tab terminal 4a.

As a result, the positioning hole 4d of the tab terminal 4a is concentrically aligned with the positioning hole 4f of the bus bar 4 at the small-diameter lower end 10a of the positioning presser pin 10, and the bending allowance 4b of the tab terminal 4a is made into the bus bar 4. Be accurately positioned. In order to prevent the tab terminal 4a from rotating,
For example, the lower end small diameter portion 10a of the positioning and pressing pin 10
Can be used as a square axis, and each positioning hole 4d, 4e, 4f can be made a square hole.

Then, when the bending allowance 4b of the tab terminal 4a is pressed against the upper surface of the bus bar 4 by the large diameter step 10b of the positioning pressing pin 10, the upper surface of the bus bar 4 and the lower surface of the bending allowance 4b of the tab terminal 4a. Uniform contact with

In this pressing state, a proper position of the bending margin portion 4b of the tab terminal 4a is laser-welded to the bus bar 4 by the laser beam LB, and when the laser welding a is completed, the laser-welded tab terminal 4a is positioned at the front and rear positions. The carrier part 4c is cut c. Then, laser welding a and cutting c of the tab terminal 4a to another position of the bus bar 4 are repeated.

When the carrier portion 4c is cut after laser welding a of all the planned tab terminals 4a to the bus bar 4 (see cross-hatching in FIG. 4 (a)), the result is as shown in FIG. Is laminated on the insulating plate 3.

In the above structure, the positioning pressing pin 10 is provided with the positioning hole 4 of the bending margin portion 4b of the tab terminal 4a.
By inserting the bending terminal portion 4b of the tab terminal 4a into the positioning hole 4f of the bus bar 4 from d, the bending margin portion 4b of the tab terminal 4a can be accurately positioned on the bus bar.

Further, by laser-welding the bending allowance 4b to the bus bar 4 with the bending allowance 4b of the tab terminal 4a being pressed against the bus bar 4 by the positioning pressing pin 10, the upper surface of the bus bar 4 and the tab are The contact between the terminal 4a and the bending margin portion 4b becomes uniform.

As a result, the positioning accuracy of the tab terminal 4a becomes accurate, and laser welding defects such as disengagement of welding, non-conduction, and cracks are less likely to occur.

Further, since the tab terminal 4a is manufactured in a continuous terminal state, the bending margin portion 4b of the tab terminal 4a is laser-welded to the bus bar 4 and then the carrier portion 4c is cut off. A series of processes such as supply, positioning, laser welding and cutting of the carrier portion 4c can be automated, and productivity is improved. It should be noted that the tab terminals 4a may be manufactured by cutting them in a continuous terminal state in advance and supplying them one by one.

When the tab terminal 4a is welded to the bus bar 4, the conventional resistance welding requires a large jig for sandwiching the bus bar between the electrodes.
It is not suitable for mass production because the processing man-hours and equipment are expensive. Further, in the case of conventional arc welding, the busbar has a narrow gap between other circuits and 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, the number of man-hours required for processing is expensive, and it is not suitable for mass production. Furthermore, ultrasonic welding requires partial plating because it is not possible to weld the bus bar with plating, and the shape of the bus bar differs one by one and jigs are required for the number of circuits. However, it is expensive and not suitable for mass production.

On the other hand, in the case of the laser welding of the present invention, compared with the resistance welding, arc welding, ultrasonic welding and the like mentioned above, the laser beam LB is non-contact, so that it can be performed with a simple jig. In addition, the tab terminal 4a can be welded to the bus bar 4, and the mass production time is good because the welding time per location is short. Further, since the laser beam LB has a small beam diameter, the laser beam LB can be connected to the bus bar 4 and the tab terminal 4a. There is an advantage that the pitch can be narrowed and the degree of freedom of wiring in the design is improved.

Among various types of laser welding, YAG laser welding is non-contact, has a small heat-affected layer,
It consumes less power and the equipment is small, it can be easily used for three-dimensional welding due to the use of optical fibers, and it is possible to perform multipoint simultaneous welding by dividing the beam.
It is most suitable because it is easy to automate and the production cost is significantly reduced.

[0031]

[0032]

[Brief description of drawings]

FIG. 1 is a tab terminal of the present invention, (a) is a plan view,
(B) is the sectional view on the AA line of (a).

FIG. 2 is a bus bar, (a) is a plan view, and (b) is a sectional view taken along line BB of (a).

3A and 3B are plan views of modified examples of tab terminals, respectively.

FIG. 4A is a plan view of a tab terminal laser-welded to a bus bar, and FIG. 4B is a cross-sectional view corresponding to line C-C in FIG. 4A showing a relationship between a positioning presser pin and a positioning hole.

FIG. 5 is a tab terminal obtained by cutting the carrier part,
(A) is a top view, (b) is a DD sectional view taken on the line of (a).

FIG. 6 is a side view of a conventional laser welding device.

FIG. 7 is an exploded perspective view of a conventional electric junction box.

FIG. 8 is a side view of a laser welded structure of a prior art bus bar.

[Explanation of symbols]

4 busbars 4a tab terminal 4b Bending margin 4c Carrier section 4d, 4e, 4f Positioning holes 10 Positioning and holding pin 10a small diameter tip 10b Large diameter step LB laser beam Laser welding c disconnection

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-174940 (JP, A) JP-A-2-65298 (JP, A) JP-A-7-245130 (JP, A) JP-A-2- 90485 (JP, A) JP-A-1-235177 (JP, A) JP-A-9-129346 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01R 43/02 H01R 43 / 16 H01R 4/58

Claims (4)

(57) [Claims] 1. A method of laser-welding a tab terminal to a bus bar housed in an electrical junction box, wherein the tab terminal is moved downward in a positioning hole formed in a bending margin portion of the tab terminal and a positioning hole formed in the bus bar. The position of the bent pin of the tab terminal is positioned on the bus bar by inserting the small diameter lower end of the presser foot and the downward movement.
A laser welding method for a bus bar, comprising laser-welding the bending allowance portion to the bus bar in a state where the bending allowance portion is pressed against the bus bar at the large-diameter stepped portion of the pressing pin . 2. The tab terminal is manufactured in a continuous terminal state in which adjacent bending margin portions are connected in series by a carrier portion, and after the bending margin portions of each tab terminal are laser-welded to the corresponding bus bars, respectively. the laser welding method of the bus bar according to claim 1 for cutting the carrier portion. 3. A tab end on a bus bar housed in an electrical junction box.
A method of laser-welding a child, wherein the tab terminals are such that adjacent bending margin portions are carrier portions.
It is manufactured with the continuous terminals connected in series with
Positioning hole formed in the carrier and the above bus bar
The positioning hole that has been
Insert the small diameter bottom end of the tab terminal carrier
Part is positioned on the bus bar and moved down,
With the large diameter step of the carrier, the carrier is pressed against the bus bar
The feature is that the bending margin is laser-welded to the bus bar.
Laser welding method for bus bars. 4. Corresponding bending margins of each tab terminal
After laser welding each to the bus bar, the above carrier
A method for laser welding a bus bar according to claim 3, wherein the portion is cut.
Law.