JPH10193138A - Ultrasonic welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a welding head to be attached with prallelism easily obtained between the pressurizing face of the welding head and the surface of an anvil, in the case where the welding head is attachable in a fitted manner to the horn in ultrasonic welding, and also to prevent the attaching state from easily loosening at the time of welding. SOLUTION: The cross sectional shape of the fitting and the contour of the head 2 are designed to be concentric squares. The head 2 is prevented from rotating against the horn 1; therefore, if the pressurizing face of the head 2 is made parallel to the surface of the anvil, the head 2 is readily made parallel to an object to be welded by merely fitting the head 2 and is free from shifting against the horn 1 when vibration is transmitted to the head 2 at the time of welding. With the head 2 refitted by rotating at an angle of 90 deg. each time, one head 2 can be used four times, enabling it to be also used for plural welding patterns such as surface welding or multipoint welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic welding apparatus, and more particularly, to an improvement in a mounting form between a horn and a welding head.

[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.

Referring to FIG. 7, a general description of an ultrasonic welding apparatus 10 will be described. In this apparatus, a horn 1 protrudes in front of a vibrating unit U, and a welding head 2 is attached to a tip of the horn 1. A plate-like welding tip (sound pole) 13 is provided on the lower surface of the welding head 2. An anvil 4 on which the workpieces u and v are placed is provided facing the lower surface of the welding head 2.

At the time of welding, the welding tip 13 and the anvil 4
The horn 1 presses them while sandwiching the workpieces u and v therebetween, and vibrates in the horizontal direction as shown by the arrow in the figure, and gives vibration energy by ultrasonic waves to the welding tip 13. Then, the coating on the contact surface between the two workpieces u and v is destroyed, and vibration heat (friction heat) is generated between the welding tip 13 and the workpieces u and v. The vibration heat causes recrystallization welding. Is performed, and the objects to be welded u and v are connected.

[0005] This ultrasonic welding has the advantages 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. .

The horn 1 of such an ultrasonic welding apparatus 10
FIG. 8 shows a conventional example in which a welding head 2 is attached to the tip of a head. In this apparatus, a mounting portion 1a of a welding head 2 at a tip of a horn 1 is a column, and a male screw 1b is formed at a part of an outer periphery from an axial end.

On the other hand, the welding head 2 is provided with a perfect circular fitting hole 2a that fits into the mounting portion 1a (column) of the horn 1, and the welding head 2 is connected to the horn 1 by the fitting hole 2a. Nut 6 screwed from the end of the horn 1
And a stepped portion 1c provided on the rear side of the mounting portion 1a, and fixed by screws.

[0008]

By the way, in the ultrasonic welding, the pressing surface on which the welding head 2 presses the workpiece, or the lower surface of the welding tip 13 and the surface of the anvil 4 (placement of the workpiece). The parallelism between the two surfaces greatly affects the connection characteristics of the connected objects u and v.

In particular, as shown in FIG.
If the welding area is not a point but is to be connected in a plane area, if the parallelism between the pressing surface of the welding head 2 and the surface of the anvil 4 does not appear, the work u , V
In the A part and the B part, the B part is strongly pressurized, the vibration is also transmitted strongly and the connection is strong, but the A part on the opposite side is not pressed and is slightly affected by the ultrasonic vibration transmitted from the B part. The connection is made only by the melting action of the vibration-generating heat, and the connected workpieces u and v vary in connection strength depending on the position between A and B, and have weak connection strength as a whole. .

Therefore, the attachment of the welding head 2 to the horn 1 depends on the degree of parallelism between the pressing surface (lower surface) of the welding head 2 and the surface of the anvil 4 (mounting surface of the workpiece). It is very important because it is involved.

However, when the welding head 2 is attached to the horn 1 according to the specification as in the above-described conventional example, the fitting cross section between the horn 1 and the welding head 2 is a perfect circle. The welding head 2 rotates delicately and it is difficult to obtain a parallel between its pressing surface and the surface of the anvil 4, and even during welding, the head 2 gradually rotates due to ultrasonic vibrations and the parallelism gradually shifts. There is that.

In this case, if welding is repeated many times after the welding head 2 is attached once and before the next head 2 is replaced, the product connected first and the product connected later are connected between the products. This results in a variation in strength. In this case, it is necessary to correct the mounting of the welding head 2 again. However, if the time interval at which the variation occurs is short, the number of corrections increases, and such work takes much time and effort. Inefficient.

Accordingly, an object of the present invention is to make it possible to easily make the parallel between the pressing surface of the welding head and the surface of the anvil easily without trouble when the welding head is attached to the horn in ultrasonic welding by a fitting type. Can be attached to the
Another object of the present invention is to prevent the parallel mounting state from being easily distorted during welding.

[0014]

In order to solve the above-mentioned problems, in the present invention, the fitting cross section between the horn and the welding head is made polygonal (claim 1). By doing so, when the head is fitted to the horn, the head does not rotate with respect to the horn as in the case where the fitting cross-sectional shape is a circle. If the basic attitude of the horn is determined so that the pressing surface (lower surface) of the horn is parallel to the surface of the anvil (the surface on which the work is placed), it is necessary to mount the head to make the work parallel to the work. It is easy, and even when vibration is transmitted from the horn to the head during welding, the head does not shift with respect to the horn.

In the structure, if the fitting cross-sectional shape and the outer shape of the welding head are concentric similar polygons (claim 2), the surface of the welding head corresponding to each side of the regular polygon is formed. If it is used as a pressing surface for the work to be welded, and the regular polygon is rotated at equal angle intervals and remounted, one head can be used by the number of sides of the regular polygon, thereby saving resources.

Furthermore, if the plurality of pressing surfaces are used by being divided into a plurality of pressing surfaces of a plurality of welding types such as surface welding and multi-point batch welding, one head can support a plurality of types of ultrasonic welding methods. can do.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below, and the same components as those in the prior art will be denoted by the same reference numerals and description thereof will be omitted. One embodiment is shown in FIGS. 1 to 6, and an ultrasonic welding apparatus 10 according to this embodiment includes a welding head fitted to a tip of a horn 1 protruding forward of a vibration unit U, similarly to the conventional example. 2 are installed.

FIG. 1A shows a mode of attachment of a welding head 2 at the tip of a horn 1 which is the main feature of the present invention. The horn 1 has a square cross section of a welding head mounting portion 1p near the end, and a male screw 1q for mounting the head 2 is cut on the outer peripheral surface over a predetermined range from the end as in the conventional example. .

On the other hand, the welding head 2 is a square plate-like body having a predetermined thickness, the size of which is fitted to the square of the cross section of the head mounting portion 1p of the horn 1 at the center of the square, and the outer shape. A square fitting hole 2p is provided so as to penetrate in such a manner that the side of the square is parallel to the side. Then, pressing surfaces 2x, 2x corresponding to a pair of opposite sides of this square head 2
Are provided with a plurality of welding tips 3,... As shown in FIG. The plurality of welding tips 3,
... will be described in detail later.

In order to mount such a welding head 2 on the horn 1, the square fitting hole 2p is fitted into the mounting portion 1p of the horn 1, and the stepped portion 1r near the rear of the horn 1 is provided.
The horn 1 is pinched with a nut 6 screwed from the end of the horn 1 and fixed with screws.

With this mounting method, since the head 2 does not rotate around the axis of the horn 1, the outer shape of the head 2, its fitting hole 2p and the mounting portion 1p of the horn 1
If the square shape of each cross section is precisely finished within a predetermined tolerance, once one side of the square of the mounting section 1p cross section of the horn 1 is made parallel to the mounting surface of the opposing anvil 4. If it is adjusted, simply by fitting the head 2 to the horn 1, the lower surface of the head 2 (the pressing surface of the work to be welded) becomes the surface of the anvil 4 (the mounting surface of the work to be welded).
And the head 2 can be easily made parallel. In addition, even during welding, the head 2 does not rotate around the axis of the horn 1, so that even if ultrasonic vibration is transmitted, the head 2 does not shift in parallel.

With the above configuration, if all four sides of the outer shape of the head 2 are subjected to a surface treatment so that the head 2 can be used for a pressing surface of a work to be welded, the head 2 is rotated by 90 ° around the axis of the horn 1. It can be rotated and re-mounted, and can be used four times with one head 2, thereby saving resources.

Further, by utilizing the provision of a plurality of pressing surfaces on one head, not all surfaces are used for pressing surfaces of the same welding form, but the welding form is changed depending on the pressing surface. In this case, a single head can perform a plurality of forms of ultrasonic welding.

Therefore, in the welding head 2 of this embodiment, as described above, a plurality of rectangular welding tips 3 are provided on the pressing surfaces 2x, 2x corresponding to a pair of opposite sides of a square outer shape, and the surfaces are formed. A plate-like welding tip 3 'covering the entire surface of each pressing surface 2y was provided on the surfaces 2y and 2y corresponding to the other pair of opposite sides so as to perform normal surface welding. With a flat pressing surface, two types of ultrasonic welding of multi-point batch welding and surface welding can be performed with one head 2. Incidentally, the pressing surface 2x (lower surface of the welding tip 3) for multi-point batch welding and the pressing surface 2y (lower surface of the welding tip 3 ') for surface welding are respectively provided on a pair of opposed surfaces.
This is for imparting symmetry to the shape of the head 2 so that ultrasonic waves can be transmitted while maintaining symmetry.

Further, in this embodiment, the plurality of welding tips 3 provided on the pressing surface 2x of the multi-point collective welding type are arranged in a staggered manner as shown in FIG. 1 (b). This will be described in detail when describing the operation.

In this embodiment, as a multi-point collective welding,
As shown in FIG. 2, a plurality of sets of electric wires a and bus bars b are welded together, and as an anvil 4 for the multi-point collective welding, a plurality of sets are provided on the mounting surfaces of the workpieces a and b. The guide grooves 4a are formed. The electric wire a and the bus bar b of the object to be welded are overlapped and fitted in the groove 4a, so that the set of each of the objects to be welded a and b is reliably set at the welding position. Note that the groove 4a can be deleted. That is, the mounting surface may be a simple plane. The ultrasonic welding apparatus according to this embodiment has the above-described configuration, and its operation will be described below. First, the case of performing multi-point batch welding will be described.

At the time of welding, first, the electric wire a and the bus bar b are placed in the groove 4a of the grooved anvil 4, and at this time, as shown in FIG. Overlap point 5 (weld point) and adjacent groove 4
The overlapping point 5 '(welding point) of the electric wire a' placed on a 'and the bus bar b' is displaced in the longitudinal direction of the groove 4a (4a ') (hereinafter, also simply referred to as the front-back direction). I did it. As described above, the plurality of welding tips 3,... Provided on the welding head 2 for multi-point collective welding are arranged in a staggered manner because the welding point between the electric wire a and the bus bar b, the electric wire a 'and the bus bar. This is because the displacement of the welding points 5 and 5 'of b' is dealt with.

In this way, as shown in FIG. 4, even if the wire a (wire a ′) is disengaged by the pressing of the welding tip 3, the adjacent wire a ′ and the bus bar b ′ ( There is no short circuit at the welding point 5 (welding point 5 ') between the electric wire a and the bus bar b).

Next, the case of surface welding will be described. As a work to be welded, wide metal plates u and v are welded to each other. In this case, as shown in FIG. The head is opposed to the anvil 4 so that the surface of the head facing the anvil 4 is the lower surface of the plate-like welding tip 3 ′ provided on the pressing surface 2 y. Although the groove 4a (4a ') is formed in the anvil 4 as described above, if the surface is smooth, the wide plates u, v
Horn 1 mounting part 1p (square section)
Is maintained parallel to the surface of the anvil 4 and the lower surface of the welding tip 3 ′ of the head 2 is also parallel to the surface of the anvil 4, and pressure is evenly applied over the entire welding surface. .

As described above, in this embodiment, the fitting cross section of the head 2 and the horn 1 is made square, so that the pressing surface 2x (or the chip 3) of the head 2 is formed.
2y (or the lower surface of the welding tip 3 ') and the surface of the anvil 4 can be easily and surely brought out, and one head 2 can perform two types of simultaneous welding and surface welding. Ultrasonic welding can be performed twice each.
In the multi-point collective welding, as described above, even if the strands are separated at the welding points 5, 5 'of the adjacent workpieces a, b and a', b ', there is no danger that they will be short-circuited.

Of course, if the head 2 is to be made a single-use disposable specification, the fitting cross-sectional shape of the horn 1 and the head 2 is simply an ordinary polygon, and when the head 2 is fitted into the horn 1, the head 2 As long as the surface facing the anvil 4 is parallel to the surface of the anvil 4,
As described above, it is not necessary to adopt a configuration in which the fitting cross-sectional shape of the welding head 2 and the horn 1 is a regular polygon, the outer shape is similar to the regular polygon, and their centers are aligned.

In this embodiment, the fitting cross section of the horn 1 and the head 2 is square. However, the shape is not limited to square, and as shown in FIG. An arbitrary regular polygon such as a triangle (FIG. 6A) and a regular hexagon (FIG. 6B) can be selected. However, it goes without saying that a regular polygon having too many corners is not preferable because it approaches a circle.

[0033]

The present invention is configured as described above.
The parallelism between the pressing surface of the welding head and the surface of the anvil can be easily obtained, and even during welding, the parallelism does not collapse, so that the workpiece is uniformly sandwiched between the pressing surface of the head and the surface of the anvil. There is no variation in the pressurizing action depending on the location,
Ultrasonic vibrations are evenly transmitted to the entire welding area, so that highly reliable connection without variation in connection strength can be realized.

Further, if the fitting cross-sectional shape of the welding head and the horn is made a regular polygon and the outer shape of the head is made similar to the regular polygon and concentric, the number of sides of the regular polygon by one head can be reduced. Can be used, or can be used for multiple types of welding, such as surface welding and multi-point batch welding.

[Brief description of the drawings]

FIG. 1A is a perspective view showing attachment of a head to a horn, and FIG. 1B is a plan view showing an arrangement of tips for multipoint batch welding in a plan view.

2A is a plan view, and FIG. 2B is a front view of the anvil according to the embodiment.

FIG. 3 is a plan view showing a mounted state of an object to be welded in the embodiment.

FIG. 4 is a plan view showing a welding result when performing multi-point batch welding in the state of FIG. 3;

FIG. 5 is a front view showing an attached state of a head at the time of surface welding in the embodiment.

FIGS. 6A and 6B are perspective views showing a regular triangular head and a regular hexagonal head in FIG. 6B;

FIG. 7 is a perspective view showing a conventional example of an ultrasonic welding apparatus.

FIG. 8 is a perspective view showing a conventional example of attaching a head to a horn of an ultrasonic welding device.

FIG. 9 is a diagram showing a defect in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Horn 1p Head mounting part 2 Weld head 2p Fitting hole 2x, 2y Pressing surface 3, 3 ', 13 Welding tip 4 Anvil 4a, 4a' Guide groove 5, 5 'Weld point (overlap point) 6 Nut 10 Ultrasonic welding Apparatus U Vibration unit a, a 'Workpiece (electric wire) b, b' Workpiece (bus bar) u, v Workpiece (plate)

Claims (2)

[Claims] 1. An ultrasonic welding apparatus in which a welding head is fitted to a horn by fitting, wherein the fitting sectional shape is polygonal. 2. The ultrasonic welding apparatus according to claim 1, wherein the fitting cross-sectional shape and the outer shape of the welding head are concentric and similar regular polygons.