JPS60210383A - Joining method of fine wire - Google Patents

Abstract

PURPOSE:To bond surely and securely a fine wire by pressing and fitting the fine wire into the fine-wire fitting part provided to a material to be joined and irradiating an energy beam like a spot to both members. CONSTITUTION:A square groove 2 is provided to a terminal 1 and the fine wire 3 is pressed and fitted into the groove 2 by means of a press-fitting jig, etc. The wire 3 is so positioned that the end thereof do not jump out of the groove 2. The laser beam B is irradiated like a spot to both members in this state. The spot center of the beam B is made coincident with the center of the wire 3 to prevent the molten state from deviating from the axis of the wire 3. The beam B joins instantaneously the wire 3 and the terminal 1 and therefore the joining in the atm. is made possible. Since the end of the terminal 1 and the boundary between the molten part and unmolten part is spaced by >=0.5 times the diameter of the wire 3, the wire 3 is surely and securely joined and the automatic joining operation is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a fine wire joining method for joining a fine wire such as a lead wire to an object to be joined such as an electronic device component.

[Background of the invention]

As a method for joining thin wires to objects to be joined such as electronic device parts, soldering, fusion welding using an energy beam such as electron beam welding or laser beam welding, pressure welding using resistance welding, etc. are used. However, in any of the conventional methods, in the case of minute materials such as thin wires, it is difficult to position the material at the joining location, and peeling or fusing is likely to occur. Also,
In the pressure welding method, it is difficult to control the pressure welding pressure, so variations in the pressure welding points are likely to occur. On the other hand, when bonding thin wires to electronic devices, etc., it is important to ensure that the thin wires are firmly bonded to the electronic device parts even under harsh conditions in the usage environment such as mechanical vibrations and shocks of the objects to be bonded, such as electronic devices. requested.

At the same time, there is a need to automate the joining process, as the number of thin wires required for joining is large and many parts rely on manual labor.

For this reason, for example, in Japanese Patent Publication No. 51-27414, a protrusion is provided at the joint part of the parts, the thin wire is sandwiched between the two sides by the protrusion, and the two are heated and welded to facilitate the positioning of the thin wire. A joining method is disclosed that prevents the occurrence of fusing.

Furthermore, Japanese Patent Publication No. 57-5636 discloses that a fitting part is provided on the parts to be joined, one end of a thin wire is fitted into the fitting part, and the joining part is irradiated with an energy beam to melt and join. discloses a bonding method that improves workability and increases bonding strength.

However, in these methods, even if the thin wire is inserted into the joint and held down, the thin wire has spring properties and therefore lifts up from the joint, making it difficult to accurately position the joint. Further, the amount of weld penetration of the thin wire at the joint portion is significant, and the cross-sectional area decreases at the fusion boundary, resulting in a strength problem. Furthermore, when the N wire is subjected to a tensile or bending load, the load is concentrated at the melting boundary.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a joining method that eliminates the drawbacks of the above-mentioned methods of welding thin wires, joins fine wires reliably and firmly, and improves the reliability of the joint.

[Summary of the invention]

To explain the joining method of the present invention, the material of the thin wire is a metal material such as copper, nickel, Kovar, etc., but if the terminal is made of plastic, it can also be applied to joining of plastic thin wire. The terminal to be joined to the thin wire and the thin wire material are not only of the same kind but also different kinds of materials. For terminals having a smaller area and volume than thin wires, square, semicircular, U-shaped, etc. grooves are formed by press working, electric discharge machining, machining, etc. It is best to make this groove deeper than the diameter of the thin wire so that the thin wire is buried in the groove. This groove can be applied to any case where the groove is machined over the entire width of the terminal or where it is machined halfway. The width of this groove is made slightly narrower than the diameter of the thin wire to be joined, and the thin wire is fitted into the groove by pressing.

The thin wire fitted into the groove is fixed in the groove due to restraint from the groove wall and does not float up. When a terminal having a groove is fixed in a predetermined position, the thin wire can be inserted into the groove easily by an automatic machine since it is easily subjected to a suppressing force.

Furthermore, for bonding, a device such as a laser processing machine or an electron beam processing machine is prepared that focuses an energy beam into a spot and irradiates the fitting portion to melt both the thin wire and the terminal member. The diameter of the beam spot is set to be larger than the width of the groove so that the two boundaries between the thin wire and the terminal are simultaneously melted. When the diameter of the thin wire is larger than the diameter of the beam spot, the energy beam is irradiated separately to the two boundary parts between the thin wire and the terminal to melt and join the thin wire and the terminal member.

[Embodiments of the invention]

Hereinafter, specific examples of the joining direction of thin wires of the present invention will be described with reference to FIGS. 1 to 3. As shown in Figure 1, the Kovar terminal l is pressed to a depth of 3.5m11 and a width of 0.2m.
9 III+, a rectangular groove 2 with a length of 1.5 m is provided. This Kovar terminal 1 is a terminal in an electrical wiring device, and is in a state that can sufficiently withstand pressure during press-fitting. A thin wire 3 made of a nickel wire having a thickness of 0.3 wm is pushed into this groove 2 using a press-fitting jig. The thin wire 3 that fits into the groove 2 is positioned so that its end does not protrude from the groove 2.

In this state, as shown in FIG. 21, a laser beam B having a beam spot diameter of 0.32 to 0.4 m is irradiated in a circular pattern. At this time, the center of the spot of the laser beam B is aligned with the center of the thin wire 3, and the molten state is positioned and irradiated so as not to be eccentric to one side with respect to the axis of the thin wire 3. The light source is a YAG laser, and since the parts are melted and joined instantly, joining can be performed in the atmosphere without covering the melted part with an inert gas. When viewed from above, the melted area at this time has a circular shape as shown in FIG. In addition, at the joining part of the thin wire 3, the dimension in the groove depth direction of the thin wire 3 did not decrease by more than 1/6 to 2/6 of the diameter dimension before joining, and the thin wire 3 made of nickel wire and the Kovar member The terminal 1 consisting of the following is well bonded. Further, the irradiation center position of the laser beam was approximately 0.7 an from the end face of the bonding member from which the thin wire 3 was taken out to the melted/unmelted boundary.

In the above embodiment, the groove is formed on the terminal, but instead of this, a grooved part is manufactured separately, this grooved part is joined to the terminal by spot welding or laser welding, etc., and then , a thin wire may be inserted into this groove and irradiated with a laser beam in a spot shape to melt and join the joint.

When bonded using the above-described bonding method, the cross-sectional area of the thin wire does not decrease significantly due to melting of a part of the thin wire 3 and the terminal 1.
Good bonding is achieved. The sharp decrease in the cross-sectional area of the thin wire 3 at the molten-unmelted boundary results in a significant decrease in strength against bending and tensile loads applied to the thin wire 3. This decrease in strength may cause the thin wire 3 to break depending on the quadruple load.

However, in the above-mentioned joining method, even if the thin wire 3 is bent or subjected to a tensile load, the deformation is suppressed by the friction between the thin wire 3 and the wall of the groove 2, and stress concentration at the molten-unmelted boundary does not occur. However, it will be alleviated considerably. When a forced repeated bending test is performed in the thickness direction of the terminal l to cause it to break, if the width of the groove 2 is wider than the diameter of the thin wire 3, it will break at the melted-unmelted boundary where the cross-sectional area decreases; The fracture stress is also considerably lower than that of the thin wire base material. On the other hand, in the case of the above-mentioned joining method, since the molten-unmelted boundary and the terminal end are separated by 0.7 mm, most of the wires break at the base material portion of the thin wire that deviates from the boundary. Therefore, the breaking strength is also comparable to that of the thin wire base material. Note that unless the melted-unmelted boundary and the end of the terminal 1 are separated from each other by at least 0.5 times the diameter of the thin wire 3, there is no effect of pressing down the wall of the groove 2. As described above, the above-described bonding method is superior in terms of strength.

Further, since the thin wire 3 is forcibly inserted into the groove 2, the thin wire 3 does not jump out due to spring force, and laser beam irradiation positioning becomes easy.

Therefore, fine wire joining work can be easily performed and automatic joining work can be performed easily.

〔Effect of the invention〕

As explained above, according to the method of the present invention, thin wires can be joined reliably and firmly, and the reliability of the joint can be improved.

[Brief explanation of drawings]

1 to 3 are diagrams explaining a specific embodiment of the method of joining thin wires according to the present invention, FIG. 1 is a perspective view showing a state in which the thin wire is fitted into a terminal of an electronic device, and FIG. 2 is a sectional view of FIG. 1, and FIG. 3 is a plan view after joining. l...terminal, 2...groove, 3...thin wire, 4...molten part. Agent Patent Attorney Meikai Takahashi' Figure 2, Figure 3

Claims (1)

[Claims]] In a thin wire joining method in which a thin wire is joined to an object to be welded by an energy beam, a thin tf! having a width equal to or less than the diameter of the thin wire is attached to the object to be welded. A fitting part is provided, and the thin wire is forcibly pushed into the fitting part, so that the thin wire is fitted so that it is held by the frictional force with the wall surface of the fitting part,
A thin wire joining method characterized by irradiating both members with an energy beam in a spot shape to melt the thin wire or both members and join them. 2. From the melting boundary between the thin wire and the object to be joined, the diameter of the thin wire is 0.
By providing the end of the object to be joined or the bent part of the thin wire at a distance of at least 5 times, the thin wire is bent by friction between the thin wire and the wall surface of the object to be joined, and the stress concentration point during a tensile load is moved away from the melting boundary. 2. The fine wire joining method according to claim 1, wherein the wire joining method is moved to a base material portion.