JPH05185252A - Ultrasonic-welding method for metal - Google Patents

Abstract

PURPOSE:To obtain the stable ultrasonic-welding between a soft metal piece, such as contacting material, and a hard metal piece, such as spring material by improving the ultrasonic welding strength which is hardly obtained since an active metal surface is difficult to be formed in a hard spring material through an active metal surface is formed by plastic flow in accordance with the deformation on the joining face of a soft contact material. CONSTITUTION:A YAG laser beam 6 irradiates the surface of the spring 2 to form a melting layer 8a melted only to the extremely thin surface layer of the spring 2. Further, by using the surface of the melting layer 8a of the spring 2, the spring 2 and the contact point 1 are ultrasonic-welded through a horn 4. Therefore, even for the hard part of the refining part and the working hardened part of the metal, etc., by executing the laser beam pre-treatment, only the extremely thin layer on the metal surface can be melted or raised to the temp. without damaging the characteristic of the material and easily activated at the time of ultrasonic-welding and the stable welding condition restraining the ultrasonic-welded deformation can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of ultrasonically welding a metal piece such as a contact material using ultrasonic waves.

[0002]

2. Description of the Related Art Conventionally, as a method of ultrasonically welding a metal piece such as a contact and a metal piece such as a spring, a method as shown in FIGS. 6 and 7 is generally mentioned. That is, as shown in FIG. 6, a concave portion 11 is provided in the anvil 3, the contact 1 is put therein, and the contact 1 is fixed so as not to move. Next, the spring 2 is placed on the contact 1, and ultrasonic vibration is applied from the spring 2 side through the horn 4 to weld the contact 1 and the spring 2. Further, as shown in FIG. 7, the spring 2 is fixed on the anvil 3, the contact 1 is placed on the spring 2, and the horn 4 is placed from the contact 1 side.
Ultrasonic vibration is applied via to weld the contact 1 and the spring 2.

[0003]

However, in these welding methods, generally soft contact materials (eg A
(g alloy, etc.) and a spring material harder than the contact material (such as bery copper or phosphor bronze) are welded, the amount of deformation of the soft contact material is larger than that of the hard spring material. It was difficult to control the contact height. Further, an active metal surface is generated on the joint surface of the soft contact material due to plastic flow accompanying the deformation, but it is difficult to obtain ultrasonic welding strength because the active metal surface is hard to be generated on the hard spring material. In order to further improve the ultrasonic welding strength, it was necessary to further increase the amount of deformation. Although the above problems can be solved to some extent by coating a hard spring material with a relatively soft material such as Cu, Ag and Al, there are problems that the cost is increased and the functionality is impaired.

The present invention has been made in view of the above circumstances, and provides an ultrasonic metal welding method for obtaining stable ultrasonic welding between a soft metal piece such as a contact material and a hard metal piece such as a spring material. The purpose is to provide.

[0005]

In order to solve the above-mentioned problems, the method for ultrasonically welding a metal of the present invention is to irradiate the surface of a metal base material with laser light in advance to soften the surface layer, and then to irradiate with laser light. It is characterized by ultrasonically welding the surfaces.

[0006]

According to the ultrasonic welding method for metals of the present invention, by irradiating the surface of the heat treated material (heat treated material) or the work hardened material with a laser, only the extremely thin layer on the surface is melted or heated. be able to. Therefore, the surface of the spring material can be softened without being impaired, so that it is easy to activate during ultrasonic welding, and the amount of ultrasonic welding deformation is suppressed.
A stable welded state can be obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings by taking the welding of a contact material and a spring material as an example. (Embodiment 1) A first embodiment will be described with reference to FIGS. 1 (a) and 1 (b). As shown in FIGS. 6 and 7 of the conventional example, for example, the material of the spring 2 is BeCu11 alloy, and the plate thickness is 0.1 m.
m, Vickers hardness is 200 Hv or more, the material of the contact 1 is an outer diameter φ2.5 mm, a thickness 0.3 mm, a material Ag alloy, ultrasonic welding (frequency 15 kHz, applied pressure 40 k).
gf, about 0.1 sec), the soft contact 1 is deformed, and the joint surface is crushed. The shear fracture strength at this time is about 10 kgf.

Therefore, as shown in FIG.
Irradiate the surface of the spring 2 with the (CO ₂ ) laser 6 (irradiation time ~
Then, a molten layer 8a is formed by melting only the extreme surface layer of the spring 2 (up to 30 μm). As a result, the Vickers hardness of the surface of the spring 2 is reduced to 100 Hv or less. Further, as shown in (b), when the spring 2 and the contact 1 are ultrasonically welded via the horn 4 using the surface of the molten layer 8a of the spring 2, there is no crushing at the joint surface and the shear fracture strength is 20
More than kgf can be obtained.

(Embodiment 2) A second embodiment is shown in FIG.
A description will be given based on (b) and (c). The contact 1 is made of, for example, an outer diameter of 2.5 mm, a thickness of 0.3 mm, and a material of Ag alloy, and a Cu backing 10 having a thickness of 0.1 is formed on the back surface of the contact 1.
mm is provided. As shown in (a), in order to stabilize the welded portion during ultrasonic welding, an unevenness of about 100 μm is formed on the lining 10 by press forming of the punch 5 or the like.
As shown in (b), since the workability by press forming deteriorates the ultrasonic weldability, the backing 10 of the contact 1 is irradiated with the YAG laser 6 to heat the surface of the forming portion. As shown in (c), the contact 1 and the spring 2 are ultrasonically welded via the horn 4. As a result, it is possible to improve the stability of ultrasonic weldability by removing the residual stress generated during forming and softening it.

As shown in FIGS. 3 (a), 3 (b) and 3 (c), the joint surface of the spring 1 in the first embodiment shown in FIG. Needless to say, the same laser treatment is effective even when the location is stabilized.

(Third Embodiment) A third embodiment will be described with reference to FIGS. 4 (a) and 4 (b). This is the first embodiment and the second
In the example, the excimer laser 7 is irradiated. Unlike the YAG laser 6, the excimer laser 7 is a laser having a wavelength in the ultraviolet region and can form a very thin molten layer (up to several μm).
As shown in (a), the excimer laser 7 can be applied to the spring 2 to form an extremely thin molten layer 8b on the surface of the spring 2. As shown in (b), the contact 1 and the spring 2 are ultrasonically welded via the horn 4. Therefore, the softening layer can be formed without impairing the material properties, and as a result, the ultrasonic weldability is improved and the welded portion is stabilized during ultrasonic welding.

FIGS. 5A and 5B show another third embodiment in which the excimer laser 7 is irradiated in the first and second embodiments. As shown in (a), by adjusting the energy density of the excimer laser 7, it is possible to instantaneously form a concavo-convex layer 9 having fine concavities and convexities of about several μm on the laser irradiation surface without work hardening. As shown in (b), the contact 1 and the spring 2 are ultrasonically welded via the horn 4. Therefore, it is possible to stabilize the welded portion during ultrasonic welding.

[0013]

As described above, according to the ultrasonic welding method for metals of the present invention, the surface of the metal substrate is irradiated with laser light in advance to soften the surface layer, and then the laser-irradiated surface is ultrasonically welded. Therefore, even in hard parts such as metal tempered parts and work-hardened parts, laser pretreatment can melt only extremely thin layers on the metal surface without sacrificing material properties. Alternatively, the temperature can be raised. Therefore,
It becomes easy to activate during ultrasonic welding, and it is possible to obtain a stable welding state in which the amount of ultrasonic welding deformation is suppressed.

[Brief description of drawings]

1A and 1B are views showing ultrasonic welding of metal in a first embodiment of the present invention.

2 (a), (b) and (c) are diagrams showing ultrasonic welding of metal in the second embodiment of the present invention. FIG.

3 (a), (b) and (c) are the other second aspects of the present invention.
It is a figure which shows the ultrasonic welding of the metal in an Example.

4 (a) and 4 (b) are diagrams showing ultrasonic welding of metal in the third embodiment of the present invention.

5 (a) and 5 (b) are views showing ultrasonic welding of metal in another third embodiment of the present invention.

FIG. 6 is a diagram showing ultrasonic welding of metal in a conventional example.

FIG. 7 is a diagram showing ultrasonic welding of another metal in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 contact 2 spring 3 anvil 4 horn 5 punch 6 YAG laser 7 excimer laser 8a, 8b melting layer 9 uneven layer 10 backing 11 recess

Claims (1)

[Claims] 1. An ultrasonic welding method for a metal, which comprises irradiating a surface of a metal substrate with laser light in advance to soften the surface layer and then ultrasonically welding the laser-irradiated surface.