JP2001068176A - Bonding method of flat terminal and pin terminal - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To join a flat terminal and a pin terminal by irradiating a laser beam to efficiently form a joint with high strength, thereby improving durability and reliability. A pin terminal (8) is provided in a pin hole (7C) of a flat plate terminal (7).
The shaft 8A is inserted with a gap, and its tip side is projected upward from the pin hole 7C. Then, the protruding end portion is melted by a laser beam, and the melted portion is formed into a pin hole 7C.
By flowing down from the upper side to the lower side, overhang portions 10A, 10B and the like of the laser bonding portion 10 are formed. Thus, by simply irradiating the pin terminal 8 with laser light, the terminals 7 and 8 can be efficiently joined in a short time without melting the flat terminal 7, and compared with means such as resistance welding or soldering. Thus, the bonding wire 6 and the hermetic seal 9 of the casing 1 can be protected from heat, external force, and the like at the time of joining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining a flat terminal and a pin terminal which is suitably used as an input / output terminal of a control unit for controlling, for example, an engine of an automobile or an automatic transmission.

[0002]

2. Description of the Related Art Generally, a control unit for controlling an automobile engine, an automatic transmission and the like is provided in an automobile engine and an automatic transmission. For example, some control units for automatic transmissions are arranged inside an oil pan or the like of an engine due to layout restrictions or the like. In such a control unit, the circuit board is shielded from the engine oil in the oil pan while being housed in a casing having a closed structure.

The control unit is provided with a plurality of input / output pin terminals connected to various sensors, actuators and the like mounted on the vehicle. It is protruding. In this case, a hermetic seal made of, for example, a glass material is provided in a portion of the casing through which each pin terminal penetrates, in order to keep the inside of the casing sealed.

[0004] The distal ends of the pin terminals projecting out of the casing are respectively joined to the flat terminals by using joining means such as resistance welding, soldering or the like, and these flat terminals are connected to various sensors, actuators, etc. of a vehicle. Is connected to

Here, when the flat terminal and the pin terminal are joined by, for example, resistance welding or the like, an L-shaped bent portion is first formed on the front end side of the flat terminal in advance, and this bent portion and the pin terminal are connected. By making contact along the length direction, a joint area between them is ensured. Then, the bent portion and the pin terminal are sandwiched by a pair of electrodes, and a current is applied between these electrodes via each terminal, thereby resistance welding the flat terminal and the pin terminal.

On the other hand, when the flat terminal and the pin terminal are joined by, for example, soldering, a pin hole is formed in advance on the front end of the flat terminal, and the front end of the pin terminal is inserted into the pin hole. Solder each terminal with.

[0007]

By the way, in the above-mentioned prior art, a flat terminal and a pin terminal are joined by using joining means such as resistance welding or soldering.

However, when using joining means such as resistance welding, it is necessary to form, for example, an L-shaped bent portion at the joint portion of the terminal, and the shape tends to be complicated. Moreover, at the time of resistance welding, current is continuously applied while pinching the pin terminal and the flat terminal using a pair of electrodes, so that not only welding work is troublesome, but also a current or a pressing force applied from the electrode to the pin terminal causes a problem. The hermetic seal provided between the pin terminal and the casing may be damaged,
There is a problem that durability and reliability are reduced.

In the case of using a joining means such as soldering, for example, the joint portion of each terminal is easily deteriorated at an early stage due to heat transmitted from high-temperature engine oil or the like.
The connection between the flat terminal and the pin terminal may become unstable.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to efficiently join a flat plate terminal and a pin terminal, and to stably connect these flat terminals for a long period of time. An object of the present invention is to provide a method of joining a flat terminal and a pin terminal, which can be held and can improve durability and reliability.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a flat plate terminal provided with a pin hole and an outer diameter at least on the tip end side smaller than the hole diameter of the pin hole of the flat plate terminal. It is applied to a joining method for joining a pin terminal having the same.

A feature of the method adopted in the first aspect of the present invention is that the tip end of the pin terminal is inserted into the pin hole with the tip end projecting from one side surface of the flat terminal, and the protruding end portion of the pin terminal is inserted. Is irradiated with a laser beam to melt the protruding end portion, and the melted portion is caused to flow into a pin hole of the flat plate terminal to join the flat plate terminal and the pin terminal.

[0013] Thereby, the projecting end portion of the pin terminal can be irradiated with laser light to melt the projecting end portion, and the melted portion flows into the pin hole of the flat plate terminal and is solidified.
The plate terminal and the pin terminal can be mechanically fastened and joined.

According to the invention of claim 2, the length of the protruding end portion of the pin terminal protruding from one side surface of the flat terminal is such that the volume of the protruding end portion is equal to the pin hole of the flat terminal. The volume is set to be 3 to 5 times as large as the volume of the annular gap formed between the pin terminal.

Accordingly, when the protruding end portion of the pin terminal is melted by the laser beam, a sufficient amount of molten metal can be formed with respect to the gap volume between the pin terminal and the pin hole.
The flat metal terminal and the pin terminal can be joined by the molten metal.

On the other hand, a feature of the method adopted by the invention of claim 3 is that the tip end of the pin terminal is inserted into the pin hole with the tip end protruding from one side surface of the flat terminal, and the protruding end of the pin terminal is inserted. It is another object of the present invention to irradiate a laser beam to a portion and a portion around the pin hole of the flat terminal to weld the respective portions.

Thus, the terminal can be welded by irradiating the laser beam to the projecting end portion of the pin terminal and the portion around the pin hole of the flat terminal.

According to the fourth aspect of the present invention, the length of the protruding end portion of the pin terminal protruding from one side surface of the flat terminal is such that the volume of the protruding end portion is equal to the pin hole of the flat terminal. The volume is set to be 1 to 2 times as large as the volume of the annular gap formed between the pin terminal.

Thus, when the projecting end portion of the pin terminal and the peripheral portion of the pin hole of the flat terminal are welded by laser light, a sufficient amount of molten metal for welding these terminals through the annular gap is provided. Can be formed.

According to the fifth aspect of the present invention, a groove is formed on the outer peripheral side of the pin terminal at a position corresponding to the pin hole of the flat terminal.

This allows the molten portion of the pin terminal to flow into the concave groove in the pin hole and to be solidified while being engaged with the concave groove.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example in which a method of joining a flat terminal and a pin terminal according to an embodiment of the present invention is applied to a control unit for an automatic transmission provided in a vehicle such as an automobile will be described. This will be described in detail with reference to the accompanying drawings.

FIGS. 1 to 9 show a first embodiment of the present invention. In the drawings, reference numeral 1 denotes a control unit casing used in the present embodiment, and the casing 1 has an opening. And a cover plate 1B welded to the box body 1A and closing the opening, and these are formed using a metal material.

Reference numeral 2 denotes a circuit board located in the casing 1 and attached to the cover plate 1B. The circuit board 2 has a plurality of circuit elements 3, 4, 5, etc. mounted thereon as shown in FIG. Are pin terminals 8, which will be described later, using bonding wires 6, etc.
8, ... are connected.

The control unit is disposed, for example, in an oil pan (not shown) of an automobile engine, and the circuit board 2 is held by the casing 1 in a state sealed from engine oil in the oil pan.
The control unit inputs and outputs signals to and from various sensors, actuators, and the like mounted on the vehicle from pin terminals 8 to be described later via the flat plate terminals 7 and the like, and an automatic transmission (both not shown). And so on.

Are a plurality of flat terminals formed of, for example, a metal plate containing copper or the like. On the base end side of each flat terminal 7, as shown in FIG. A circular pin hole 7C is provided to open on 7A and the lower surface (other side surface) 7B. Further, the flat terminal 7 is connected at its tip end to various sensors, actuators, and the like of the vehicle.

Reference numerals 8, 8,... Denote input / output pin terminals provided on the control unit. Each of the pin terminals 8 is formed using a metal material containing, for example, iron, nickel, or an alloy thereof. . The pin terminal 8 is fixed to the cover plate 1B of the casing 1 via a hermetic seal 9 made of a glass material or the like, and has a cylindrical shaft portion 8A protruding from both sides of the cover plate 1B. The bonding wire 6 is integrally formed on the base end side of the shaft 8A.
And a land portion 8B connected to the circuit board 2 using the same.

Here, the tip of the shaft portion 8A is
It has an outer diameter smaller than the diameter of the pin hole 7C, and is inserted into the pin hole 7C with an annular gap S1 as described later, and the pin hole 7C is
Is joined within.

Reference numerals 10, 10,... Denote laser joints provided between the flat terminals 7 and the pin terminals 8, respectively. Each of the laser joints 10 comprises a shaft 8A of the pin terminal 8 as described later. The protruding end 11 is irradiated with laser light to
Is formed integrally with the shaft portion 8A.

The laser joint 10 is located on the upper and lower sides of the flat terminal 7 and extends radially outward from the shaft 8A of the pin terminal 8 beyond the pin hole 7C.
A, 10B, a gap S1 between the shaft portion 8A and the pin hole 7C.
And a cylindrical connecting portion 10C connecting the overhanging portions 10A and 10B. The upper and lower overhangs 10A and 10B are fastened to the pin hole 7C in such a manner that the shaft 8A does not come off in both the upper and lower directions.
And the pin terminal 8 are integrally joined.

The flat terminal 7 and the pin terminal 8 joined by the method according to the present embodiment have the above-described configuration. Next, the joining method will be described with reference to FIGS.

First, after assembling the control unit in advance, flat terminals 7 corresponding to the respective pin terminals 8 protruding from the cover plate 1B are prepared.

Then, in the pin terminal insertion step shown in FIG. 5, the shaft 8A of the pin terminal 8 is inserted into the pin hole 7C of the flat terminal 7 with a gap S1 (see FIG. 4), and the leading end thereof is connected to the flat terminal 7a. A predetermined length L1 upward from the upper surface 7A of the
The protruding end portion 11 is protruded by a distance. In this case, the length dimension L1 of the protruding end 11 is determined so that the volume of the protruding end 11 is, for example, about 3 to 5 times the volume of the gap S1.

Next, in the pin terminal melting step shown in FIG.
For example, a laser beam such as a carbon dioxide gas laser or a ruby laser is used to irradiate the protruding end portion 11 of the pin terminal 8 with laser light.
The protruding end 11 is gradually melted to form a fused portion 12.
In this case, as shown by a characteristic line 13 in FIG. 7, the laser beam applied to the protruding end portion 11 has a substantially rectangular pulse waveform having a pulse width T of, for example, about 5 to 20 ms.
It is output only about 4 to 5 times at a cycle of about Hz.

It is to be noted that a metal material having poor laser light absorption,
For example, when the pin terminal 8 is formed using a copper alloy or the like, the surface may be irradiated with laser light in a state where a plating process having high heat resistance such as nickel plating is performed in advance.

Next, in the terminal fastening process shown in FIGS. 8 and 9, for example, as shown by the characteristic line 14, the inclined portions 14A, 14B
A laser beam having a substantially trapezoidal pulse waveform provided with a laser beam is applied to the melting portion 12 a plurality of times at substantially the same cycle as the characteristic line 13, and this melting portion 12 is inserted into the pin hole 7 </ b> C from the upper surface 7 </ b> A of the flat terminal 7. Through the gap S1, and the melted portion 12 is caused to flow downward from the pin hole 7C to a position protruding from the lower surface 7B.

In this case, when each pulse waveform rises, the laser output gradually increases in accordance with the inclined portion 14A of the characteristic line 14, so that the molten portion 12 flows smoothly into the gap S1 in the pin hole 7C. Can be. When each pulse waveform falls, the slope 14
As the laser output gradually decreases in accordance with B, air bubbles and the like mixed in the molten portion 12 can be discharged.

Then, as shown in FIG. 4, the molten portion 12 is solidified in a state where the projecting portions 10A and 10B of the laser joining portion 10 and the connecting portion 10C are formed. It is joined via the joint 10.

Thus, in the present embodiment, the pin terminal 8
After the shaft portion 8A is inserted into the pin hole 7C of the flat plate terminal 7, the protruding end portion 11 protruding from the upper surface 7A is melted by a laser beam, and the melted portion 12 is caused to flow into the pin hole 7C so that the flat plate terminal 7 is formed. 7 and the pin terminal 8 are joined together, so that the laser joint 10 can be formed by the melted portion 12 flowing into the pin hole 7C, and the flat plate terminal 7 and the pin terminal 8 can be formed using the laser joint 10. It can be fastened mechanically.

In this case, the length of the protruding end portion 11 is set so that the volume of the protruding end portion 11 becomes, for example, about 3 to 5 times the volume of the gap S1 between the pin terminal 8 and the pin hole 7C. Since the dimension L1 is set, a sufficient amount of the molten portion 12 with respect to the volume of the gap S1 can be formed by fusing the protruding end portion 11. And the pin terminal 8 can be stably bonded.

Further, the molten portion 12 flowing into the pin hole 7C from the upper surface 7A side of the flat terminal 7 is caused to flow downward below the lower surface 7B. , 10B and connecting part 10C
Can be easily formed, and these overhanging portions 10A, 10B
The pin terminal 8 can be held in the pin hole 7C in a retaining state by using the method described above.

Therefore, according to the present embodiment, these terminals 7, 8 can be easily formed only by irradiating the laser beam to melt the protruding end 11 of the pin terminal 8 without melting the flat terminal 7. It is not necessary to limit the material and shape (joining area) of the terminals 7 and 8 in consideration of, for example, suitability at the time of welding, and a combination of metal materials used for these terminals 7 and 8 can be freely selected. In addition, the terminal shape can be simplified.

By irradiating a pulsed laser beam a plurality of times, the flat terminals 7 and the pin terminals 8 can be short-lived as compared with the case of using means such as resistance welding or soldering as in the prior art. In addition to the above, the bonding wire 6 and the hermetic seal 9 need only be applied in a non-contact state to the pin terminal 8 in a minimum amount of heat.
Can be protected from heat, external force, and the like during joining.

Further, when the control unit is disposed in the oil pan of the engine, the laser joint 10
However, even when the temperature becomes relatively high due to the heat of the engine oil, the bonding state can be favorably maintained over a long period of time as compared with the bonding portion formed by soldering or the like, and the durability and reliability can be improved.

Further, by using the laser means, the gap S1 between the pin terminal 8 and the pin hole 7C can be formed larger than in the case of soldering or the like. 8A can be easily inserted into the pin hole 7C.

In the pin terminal melting step, the pin terminals 8
The laser beam having a pulse-like output waveform is applied to the projecting end portion 11 a plurality of times, so that the projecting end portion 11 can be gradually melted in a stable state by using a plurality of pulses of laser light. Compared with the case of irradiating only one pulse of the laser light, it is possible to prevent the protruding end portion 11 from dissipating and evaporating.

Next, FIGS. 10 to 12 show a second embodiment of the present invention. The feature of this embodiment is that a tapered surface portion is formed in a pin hole of a flat terminal and the outer peripheral side of the pin terminal is formed. That is, a concave groove is provided.

Reference numeral 21 denotes a flat terminal used in the bonding method of the present embodiment. The flat terminal 21 is formed of a metal flat plate containing, for example, copper or the like in the same manner as in the first embodiment.
A circular pin hole 21C is formed on the upper surface 21A and the lower surface 21B. Further, the flat plate terminal 21 is provided with an annular tapered surface portion 21D which is inclined so as to increase the diameter of the lower opening of the pin hole 21C.

Reference numeral 22 denotes a pin terminal formed using a metal material containing, for example, iron, nickel, or an alloy thereof.
The pin terminal 22 includes a cylindrical shaft portion 22A and a land portion (not shown). Also, as shown in FIGS. 11 and 12, the shaft portion 22A has, for example,
By chamfering the places, concave grooves 22B, 22B opening at positions corresponding to the pin holes 21C are formed.

Numeral 23 denotes a laser joint where the flat plate terminal 21 and the shaft 22A of the pin terminal 22 are joined.
Reference numeral 3 is composed of upper and lower overhangs 23A and 23B and a connecting portion 23C, similarly to the laser bonding portion 10 of the first embodiment. In this case, the lower overhang 23B
Is extended so as to expand radially outward along the tapered surface portion 21 </ b> D of the flat terminal 21. Also, the connecting portion 23
C is engaged so that its inner peripheral side portion bites into each groove 22 </ b> B of the pin terminal 22.

At the time of joining the flat terminal 21 and the pin terminal 22 thus configured, the pin holes 21C of the flat terminal 21 are formed.
After forming a tapered surface portion 21D in advance and forming a concave groove 22B in the shaft portion 22A of the pin terminal 22, the pin terminal insertion step shown in FIG. 11 is performed in substantially the same procedure as in the first embodiment. A terminal fusing step and a terminal fastening step are performed, and these terminals 21 and 22 are joined.

Thus, in the present embodiment having the above-described structure, substantially the same operation and effect as those of the first embodiment can be obtained. And especially in this embodiment,
Since the tapered surface portion 21D is formed in the pin hole 21C of the flat plate terminal 21, when the melted portion of the pin terminal 22 melted by the laser means flows from the upper side to the lower side in the pin hole 21C, the melted portion is formed into the tapered surface portion. It is possible to smoothly project radially outward along 21D, and to form a large projecting portion 23B of the laser joining portion 23, and to further increase the joining strength between the flat terminal 21 and the pin terminal 22.

Further, since each groove 22B is formed in the pin terminal 22, when the protruding end portion of the shaft portion 22A is melted, a part of the melted portion flows into the groove 22B, and The connecting portion 23C can be engaged with the concave groove 22B, and the pin terminal 22 and the laser joining portion 23 can be integrally formed with higher strength.

Next, FIGS. 13 to 15 show a third embodiment of the present invention. The feature of this embodiment is that a flat plate terminal and a pin terminal are irradiated with laser light to weld each terminal. It is in.

Reference numeral 31 denotes a flat terminal used in the bonding method according to the present embodiment. The flat terminal 31 is formed using a metal material containing, for example, iron, nickel, copper, or an alloy thereof, and has a base end side. Has a circular pin hole 31A.

Reference numeral 32 denotes a pin terminal formed using substantially the same metal material as the flat terminal 31. The pin terminal 32 has a cylindrical shaft portion 32A and a land portion (not shown). .

Reference numeral 33 denotes a laser welded portion obtained by welding the flat plate terminal 31 and the shaft portion 32A of the pin terminal 32.
3 is a flat terminal 31 and a pin terminal 32 using a laser means.
And are formed integrally with it.

Here, a method of joining the flat terminal 31 and the pin terminal 32 will be described. First, in the pin terminal insertion step shown in FIG.
One end of the pin hole 31A is inserted into the pin hole 31A with a gap S2, and the tip end is made to protrude upward from the upper surface of the flat terminal 31 by the length L2 as a protruding end 34. In this case, the length dimension L2 of the protruding end portion 34 is determined so that the volume of the protruding end portion 34 is, for example, about 1 to 2 times the volume of the gap S2. Via terminal 31,
32 is formed so as to form a sufficient amount of molten metal for welding.

Next, in the pin terminal melting step, for example, FIG.
A laser beam having a pulse waveform shown by a characteristic line 35 in FIG. 5 is irradiated to the protruding end portion 34 of the pin terminal 32 and the vicinity of the pin hole 31A of the flat terminal 31 by one pulse to form a laser welded portion 33. . In this case, when the pulse waveform falls, the laser output gradually decreases according to the inclined portion 35A of the characteristic line 35, so that air bubbles and the like contained in the laser welded portion 33 can be discharged.

Thus, in the present embodiment having the above-described structure, substantially the same operation and effect as those of the first embodiment can be obtained. And especially in this embodiment,
Since the flat terminal 31 and the pin terminal 32 are formed using substantially the same metal material and the terminals 31 and 32 are laser-welded, the flat terminal 3 made of the same metal material is used.
1 and the pin terminal 32 can be welded with high strength. In addition, by forming a laser welded portion 33 by irradiating one pulse of laser light, these terminals 31, 32 are formed.
Can be joined in a shorter time.

In each of the above embodiments, the shaft portions 8A, 22A, 32A of the pin terminals 8, 22, 32 are formed in a columnar shape having a substantially constant outer diameter, and the outer diameters thereof are set to the plate terminals 7, 2. Although it has been described that the pin holes 21C and 21C are formed smaller than the hole diameters of the pin holes 7C, 21C and 31A, the present invention is not limited to this. What is necessary is just to form it smaller than the hole diameter of a pin hole, and the shape and dimensions other than this insertion part may be freely set.

Further, in each of the above embodiments, the column-shaped pin terminals 8, 22, 32 are used. However, the present invention is not limited to this, and these pin terminals 8, 22, 32 are used.
Instead of this, for example, a pin terminal having a non-circular cross section such as a polygon or an ellipse may be used, or a pin hole of a flat terminal may be formed in a non-circular shape.

Further, in the second embodiment, the two concave grooves 22B and 22B are provided on the outer peripheral side of the pin terminal 22, but the present invention is not limited to this, and the entire circumference of the pin terminal is provided. It may be configured to provide an annular groove that extends.

In the second embodiment, the flat terminals 2
1 is provided with a tapered surface portion 21D for increasing the diameter of the lower opening of the pin hole 21C. However, the present invention is not limited to this. For example, as shown by a virtual line in FIG.
1 may be provided with a tapered surface portion 21D 'for increasing the diameter of the upper opening of the pin hole 21C.

Further, in the embodiment, the case where the joining method of the flat terminal and the pin terminal is applied to a control unit for an automatic transmission mounted on a vehicle such as an automobile has been described as an example. The present invention is not limited to this, and can be applied to a case where a flat terminal and a pin terminal provided on various electronic components other than the control unit are joined.

[0066]

As described above in detail, according to the first aspect of the present invention, the protruding end portion of the pin terminal that protrudes from the pin hole of the flat plate terminal is melted by the laser beam, and the melted portion flows into the pin hole. Since the flat terminal and the pin terminal are joined to each other, the molten portion of the pin terminal flows into the pin hole of the flat terminal and solidifies, so that these terminals can be mechanically fastened. Therefore, compared to the case of using means such as resistance welding or soldering, these terminals can be efficiently joined in a short time without melting the flat terminals only by melting the pin terminals with the laser beam, For example, there is no need to limit the material, shape, and the like of each terminal in consideration of the suitability at the time of welding, and the shape can be simplified. In addition, it is only necessary to apply a minimum amount of heat to the pin terminals in a non-contact state, and it is possible to protect parts around the pin terminals from heat and external force at the time of joining, and each terminal becomes relatively hot. Even in this case, the bonding state can be favorably maintained over a long period of time as compared with a bonding portion formed by soldering or the like, and the durability and reliability can be improved.

According to the second aspect of the present invention, the length of the protruding end portion of the pin terminal is such that the volume of the protruding end portion is an annular gap formed between the pin hole of the flat plate terminal and the pin terminal. Is set to be 3 to 5 times the volume of the pin terminal, so that when the protruding end portion of the pin terminal is melted by the laser beam, a sufficient amount of melting is required for the gap volume between the pin terminal and the pin hole. A metal can be formed, and the flat metal terminal and the pin terminal can be stably bonded by the molten metal.

On the other hand, according to the third aspect of the present invention, the protruding end portion of the pin terminal protruding from the pin hole of the flat plate terminal and the portion around the pin hole of the flat plate terminal are welded by laser light. A flat terminal and a pin terminal made of the same metal material can be welded with high strength, and the welding operation can be performed in a shorter time and more efficiently than when using means such as resistance welding or soldering. In addition, it is only necessary to apply a minimum amount of heat in a non-contact state to the pin terminal, and it is possible to protect parts around the pin terminal from heat and external force at the time of welding and each terminal becomes relatively high temperature. Even in this case, the bonding state can be favorably maintained over a long period of time as compared with a bonding portion formed by soldering or the like, and the durability and reliability can be improved.

According to the fourth aspect of the present invention, the length of the protruding end portion of the pin terminal is determined by the annular gap formed between the pin hole of the flat terminal and the pin terminal. Since the volume is set to be 1 to 2 times the volume of the molten metal, it is possible to form a sufficient amount of molten metal to weld each terminal through the annular gap by the protruding end portion.

Further, according to the fifth aspect of the present invention, since the concave groove is formed on the outer peripheral side of the pin terminal, when the molten portion of the pin terminal flows in the pin hole, the molten portion is formed into a tapered surface portion. , And a part of the molten portion of the pin terminal can be caused to flow into the concave groove and solidified while being engaged with the concave groove. Thereby, the bonding strength between the flat terminal and the pin terminal can be further increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of a control unit to which a first embodiment is applied.

FIG. 2 is a longitudinal sectional view of the control unit viewed from the direction of arrows II-II in FIG.

FIG. 3 is an enlarged sectional view of a main part in FIG. 2, showing a state in which a flat terminal and a pin terminal are joined by the joining method according to the first embodiment.

FIG. 4 is an enlarged cross-sectional view showing a laser bonding part in FIG.

FIG. 5 is an enlarged cross-sectional view showing a state in which the tip end side of the pin terminal is inserted into the pin hole of the flat terminal in the pin terminal insertion step.

FIG. 6 is an enlarged cross-sectional view showing a state in which a protruding end of a pin terminal is melted by irradiating a laser beam in a pin terminal melting step.

FIG. 7 is a characteristic diagram showing a pulse waveform of a laser beam applied to a protruding end of a pin terminal in a pin terminal melting step.

FIG. 8 is an enlarged cross-sectional view showing a state in which a laser beam is irradiated in a terminal fastening step to cause a molten portion of the pin terminal to flow into a pin hole of the flat plate terminal.

FIG. 9 is a characteristic diagram showing a pulse waveform of a laser beam applied to a fused portion of a pin terminal in a terminal fastening step.

FIG. 10 is an enlarged cross-sectional view showing a state in which a flat terminal and a pin terminal are joined by the joining method according to the second embodiment.

FIG. 11 is an enlarged sectional view showing a flat terminal and a pin terminal in a pin terminal insertion step.

FIG. 12 is a cross-sectional view of the flat terminal and the pin terminal as viewed from the direction indicated by arrows XII-XII in FIG. 11;

FIG. 13 is an enlarged cross-sectional view showing a state in which a flat terminal and a pin terminal are joined by the joining method according to the third embodiment.

FIG. 14 is an enlarged sectional view showing a flat terminal and a pin terminal in a pin terminal insertion step.

FIG. 15 is a characteristic diagram showing a pulse waveform of a laser beam applied to a flat terminal and a pin terminal.

[Explanation of symbols]

 7, 21, 31 Flat terminal 7C, 21C, 31A Pin hole 8, 22, 32 Pin terminal 21D Tapered surface 22B Groove

Claims (5)

[Claims] 1. A joining method for joining a flat plate terminal provided with a pin hole and a pin terminal having an outer diameter smaller than the hole diameter of the flat plate terminal at least on the front end side. The pin terminal is inserted into the pin hole with the side projecting from one side surface of the flat terminal, and the protruding end portion of the pin terminal is irradiated with laser light to melt the protruding end portion. A method of joining a flat terminal and a pin terminal, wherein the flat terminal and the pin terminal are joined by flowing into a pin hole of the terminal. 2. A length of a protruding end portion of the pin terminal protruding from one side surface of the flat terminal, wherein a volume of the protruding end portion is formed between a pin hole of the flat terminal and the pin terminal. The method for joining a flat terminal and a pin terminal according to claim 1, wherein the flat terminal is set to be three to five times the volume of the annular gap to be formed. 3. A joining method for joining a flat plate terminal provided with a pin hole and a pin terminal having an outer diameter smaller than the hole diameter of the flat plate terminal at least on the front end side, wherein: Side is protruded from one side surface of the flat terminal, is inserted into the pin hole, and the protruding end portion of the pin terminal and the peripheral portion of the pin hole of the flat terminal are irradiated with laser light to irradiate the respective portions. A method of joining a flat terminal and a pin terminal by welding. 4. A length of a protruding end portion of the pin terminal protruding from one side surface of the flat terminal, wherein a volume of the protruding end portion is formed between a pin hole of the flat terminal and the pin terminal. 4. The method for joining a flat terminal and a pin terminal according to claim 3, wherein the volume is set to be 1 to 2 times the volume of the annular gap to be formed. 5. The flat terminal and the pin terminal according to claim 1, wherein a concave groove is formed at a position corresponding to a pin hole of the flat terminal on an outer peripheral side of the pin terminal. Joining method.