JPH10175083A - Ultrasonic welding method and its machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate variance in joining strength of each weld point in multipoint ultrasonic welding. SOLUTION: Multipoint welding is performed with welding objects a, b interposed between a tip 3 vibrated by a horn 1 and an anvil 4. In this case, each tip 3 is arranged circular-arcuately, with the center of the circular arc made the center O of the horn 1, so that distance is equal from the center O of the horn 1 to each tip 3. Consequently, the vibration energy is uniformly transmitted to each tip 3, equalizing the welding conditions of each weld point, and thereby enabling variance-free stable joining strength (quality) to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ultrasonic welding for electrical connection of single-core electric wires, stranded electric wires, copper foils and the like, joining of resin and other materials, and more particularly to a multipoint batch ultrasonic welding method and welding machine. Things.

[0002]

2. Description of the Related Art Conventionally, ultrasonic welding is performed together with resistance welding as one of the joining methods of metal parts such as a single core electric wire, a stranded electric wire, and a copper foil. A general one of the ultrasonic welding machine 10 will be described with reference to FIG. 1. A welding head 2 is provided to project downward from a tip of a horn 1 projecting forward of a vibrating unit U. The chip (sound pole) 3 is provided. An anvil 4 is provided so as to face the welding tip 3. The anvil 4 is pressurized with the workpieces a and b sandwiched between the two 3 and 4, while applying ultrasonic vibration energy to the welding tip 3. By vibrating to clean the interface between the workpieces a and b, recrystallization welding is performed by vibrational heat (frictional heat) generated between the workpieces a and b.

[0003] This ultrasonic welding has the advantage that the joining temperature is lower than that of resistance welding, so that the base material is not easily damaged, brittle products are not found at the joint with the dissimilar metal, and the cost is low. In addition, as shown in FIG. 6, a plurality of chips 3 are formed on the welding head 2 so that multiple points can be connected at a time. In addition, there is an advantage that the present invention can be applied to joining of any material that can be thermally joined such as resin. .

[0004]

In the ultrasonic welding having such advantages, the conventional multi-point simultaneous connection is achieved by a method in which the tip 3 of the welding machine 10 is flat-mounted on the anvil 4 as shown in FIG. The workpieces a and b are interposed between the anvil 4 and the tip 3 in parallel (in a straight line) to the mounting surface.

In this welding, the horn 1 is moved back and forth (FIG. 1).
Vibration in the direction of the arrow) gives vibration energy to each chip 3. When each chip 3 is arranged in a straight line, the distance r from the center O of the horn 1 to each chip 3 as shown in FIG. And the energy transmitted to each chip 3 is different. For this reason, there is a difference in the degree of welding between each tip 3 and the anvil 3. That is, quality (joining strength) varies between connection points (welding points). In recent years, higher reliability has been demanded for automobiles, electric and electronic devices, and the like, and stable and high quality is also required for connection parts (welded parts) of these components.

An object of the present invention is to eliminate variations in bonding strength at various connection points in the above-described multipoint connection.

[0007]

In order to solve the above-mentioned problems, the present invention relates to a multi-point connection by ultrasonic welding as described above, wherein each welding point is arranged in an arc shape around a horn to form a multi-point connection. A batch connection is made (claim 1). In this way, the distance from the center of the horn to each welding point is smaller than in the conventional case where the tip is straight, so that the difference in transmission of vibration energy from the horn to each welding point is also reduced. Thus, the difference in bonding strength is reduced.

At this time, if the center of the arc formed by each of the welding points is made to coincide with the center of the horn (claim 2), the distance from the center of the horn to each welding point becomes equal, and the vibration energy becomes equal. The welding conditions at each welding point become equal, and stable joining strength (quality) without variation can be obtained.

As a welding machine capable of performing the above welding method,
In an ultrasonic welding machine in which a plurality of workpieces are interposed between the tip and the anvil vibrated by the horn, and the multipoint is connected collectively, the interposed surface of the workpiece of the anvil and the tip is
The horn may be formed in an arc shape around the horn (Claim 3), and the center of the arc-shaped intervening surface may coincide with the center of the horn (Claim 4).

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS. 1 to 4. In this embodiment, a welding head 2 is fitted to a tip of a horn 1 protruding forward of a vibration unit U, as in the prior art. 2a, a plurality of chips 3 are formed at the tip of the head 2. Each of the chips 3 is arranged in an arc around the horn 1 so as to be equidistant from the center O of the horn 1 as shown in FIGS. The number of chips 3 is determined by the workpieces a and b
Is determined as appropriate in accordance with the number.

A guide groove 4a is formed on the mounting surface of the anvil 4 on which the workpieces a and b are mounted. By fitting the workpiece a such as an electric wire into the groove 4a, each workpiece a is welded. Be sure to set in position. The groove 4a can be deleted. That is, the mounting surface may be a simple curved plane.

This embodiment has the above configuration. The operation thereof will be described below. As shown in FIG. 3, an insulated wire a and a bus bar b made of copper, brass, another iron-based alloy or the like are used.
Are placed back and forth on the anvil 4 with their ends overlapped, the head 2 is lowered, and each chip 3 is pressed against its overlapping point to perform ultrasonic welding.

At this time, each chip 3 is located at the center O of the horn 1.
, The vibration energy is transmitted evenly, and the respective overlapping points of the electric wire a and the bus bar b are welded with uniform joining strength. Further, since the respective overlapping points (chips 3) are shifted back and forth, the pressing of the chips 3
Even if the wires of the electric wire a are disjointed, there is a space to the adjacent bus bar b or the electric wire a. Incidentally, as long as the electric wire a is coated with the insulation, there is no problem even if the electric wire a makes contact.

In this embodiment, the overlapping point (chip 3) of the electric wire a and the bus bar b is shifted back and forth. However, as shown in FIG.
It is needless to say that the effects of the present invention can be obtained by arranging in an arc shape (the center of the arc also includes the center of the horn 1). The workpieces a and b are electric wires,
The present invention is not limited to bus bars, and it is needless to say that the present invention can be applied to any material that can be ultrasonically welded, such as resin, as well as various metal joints such as electric wires and electric wires, bus bars and bus bars.

[0015]

As described above, according to the present invention, the vibration energy can be almost uniformly transmitted from the horn to each chip, so that even in multi-point batch welding, there is little variation in the joining strength at each welding point. . For this reason, stable high quality can be ensured even for joining of components requiring high reliability, such as automobiles and electric / electronic devices.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment.

FIG. 2 is a front view of the embodiment.

FIG. 3 is a plan view of the embodiment with a part removed.

FIG. 4 is a chip layout diagram of the embodiment.

5A and 5B show another embodiment, in which FIG. 5A is a layout diagram of a chip, and FIG. 5B is a layout diagram of an object to be welded.

FIG. 6 is a front view of a conventional example.

[Explanation of symbols]

 U Vibration unit a Work piece (electric wire) b Work piece (bus bar) 1 Horn 2 Welding head 2a Tightening nut 3 Tip 4 Anvil 4a Guide groove for work piece 10 Ultrasonic welding machine

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B23K 101: 38

Claims (4)

[Claims] 1. An ultrasonic welding method in which multi-point connection is performed by arranging each welding point in an arc shape around a horn in multi-point connection by ultrasonic welding. 2. The ultrasonic welding method according to claim 1, wherein the center of the arc formed by each of said welding points coincides with the center O of said horn. 3. An ultrasonic welding machine in which a plurality of workpieces a and b are interposed between a tip 3 vibrated by a horn 1 and an anvil 4 to make a multi-point collective connection. An ultrasonic welding machine characterized in that the interposed surfaces of the workpieces a and b are formed in an arc shape around the horn 1. 4. The ultrasonic welding machine according to claim 3, wherein the center of the arc-shaped intervening surface coincides with the center O of the horn.