JP2000107872A - Horn of ultrasonic welding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve weld strength and to ultrasonically weld conductors to a bus bar. SOLUTION: A recessed part 10a having a small cross-sectional area in the direction orthogonal to the axial direction with respect to the whole cross- sectional area of conductors is provided in the central part of a pressurizing surface 10-1 of a horn 10 of a ultrasonic welding machine along the axial direction of an electric wire and horizontal surfaces 10b in the both sides of the recessed part 10a are provided. The conductors S are firmly held between the pressurizing surface 10-1 and the bus bar 12, the conductors S in the recessed part 10a are pushed into and pressurized with the horizontal surfaces 10b to be ultrasonically welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horn for an ultrasonic welding machine, and more particularly to a method for ultrasonically welding a core wire such as an electric wire and a metal plate such as a bus bar.

[0002]

2. Description of the Related Art Conventionally, ultrasonic welding is sometimes used to directly join an electric wire and a metal plate such as a bus bar. The core wire of the electric wire is pressed against the metal plate with a horn of an ultrasonic welding machine and sandwiched. Weld by vibrating while applying pressure. As the shape of the pressing surface of the horn of the ultrasonic welding machine, a dome shape shown in FIG. 5A and a flat shape shown in FIG. 6A are used.

[0003]

When ultrasonic welding is performed with a dome-shaped horn 1, it is difficult to set the distance between the horn 1 and the bus bar 2 during welding, and in particular, the core wire of the electric wire does not intervene. In some cases, both ends 1b of the horn 1 and the bus bar 2 come into contact with each other, and when they come into contact with each other, the welding conditions change, and there is a problem that the specified welding strength cannot be ensured.
Is thin and may be worn or damaged. Further, as shown in FIG. 5 (B), if a part of the core wire S is loosened to the left and right, a core wire S1 deviating from the inside of the dome 1a at the time of welding pressurization is generated, and the number of the core wires S inside the dome 1a is reduced. Due to the decrease, the compression ratio of the core wire S is insufficient, so that the core wire becomes difficult to melt, and there is a problem that welding conditions are not stable.

[0004] When the flat horn 1 'is used, the horn 1' and the bus bar 2 'do not come into contact with each other because the core S intervenes the entire pressing surface 1a', and the compression rate of the core S is stable. The strength of the horn 1 'itself is also increased because there is no thin portion. However, FIG.
As shown in (B), since the pressing surface 1a 'has a flat shape, when the horn 1' is pressed, only the single core wire S is placed on the upper surface of the bus bar 2 ', and the number of the core wires S increases. , The core wire S2 protrudes from the upper surface of the bus bar 2 ',
There is a problem of short-circuiting with the adjacent bus bar 2'-1. The number of core wires S placed on the bus bar 2 'is calculated, for example, if the width of the bus bar is 1.5 mm, only four core wires of φ0.32 mm can be placed.

[0005] To solve the above-mentioned problem, Japanese Utility Model Publication No. 6-225
No. 57, a horn 1 "of an ultrasonic welding machine shown in FIG.
Has been proposed. The horn 1 "is provided with a groove 1a" in which the width of the inlet is wider than the width of the back, so that the core wire is gathered inside the groove 1a "by the vibration of the ultrasonic wave, and the core wire is formed from a metal plate. Although it does not protrude, both ends 1b "have a thin portion and both ends 1b"
Since it is difficult to set the distance between b ″ and the metal plate, there is a possibility that both ends 1b ″ may be worn or damaged, as in the case of the dome-shaped horn 1 described above.

The present invention has been made in view of the above-mentioned problems, and it is a first object of the present invention to stabilize the compressibility and welding conditions of a core wire during ultrasonic welding and improve the welding strength between the core wire and a metal plate. It is an issue. A second object is to prevent the core wire from protruding from the upper surface of the metal plate. A third object is to prevent the pressing surface of the horn from coming into contact with the upper surface of the metal plate.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a horn of an ultrasonic welding machine for joining a core of an electric wire to a metal plate, wherein the horn is required in the axial direction of the core. A pressing surface for pressing the entire lower surface thereof against the core wire of the electric wire, and a central portion of the pressing surface in the core wire cross-sectional direction, a concave portion smaller than the total cross-sectional area of all the core wires, on both sides of the concave portion. Provided is a horn of an ultrasonic welding machine having a horizontal surface and pressing a concave portion of the horn against a core wire placed on the upper surface of the metal plate, and pressing a core wire overflowing from the concave portion on the horizontal surface. I have.

As described above, the pressing surface of the horn according to the present invention has a shape having both a dome shape and a flat shape, that is, a concave portion is provided at the center of the pressing surface, and a flat horizontal surface is formed on both sides of the concave portion. The contact area with the core wire can be increased by this shape. Also, when pressing the pressing surface against the core wire, while pressing the core wire into the concave portion, and pressing the core wire overflowing from the concave portion on the horizontal surface on both sides of the concave portion so as to be sandwiched, in the past, the portion which has protruded from the metal plate The core wire can be absorbed by the concave portion so that the core wire does not protrude from the metal plate.

Also, since the core wire is securely sandwiched in the horizontal plane, the compressibility of the core wire can be stabilized and the welding strength can be improved, and the pressurized surface comes into direct contact with the metal plate due to the interposition of the core wire. Can be prevented. Furthermore, since the cross-sectional area of the recess is smaller than that of the conventional dome-shaped horn, both sides of the recess have a sufficient thickness, and the strength of the horn itself can be increased.

It is preferable that the cross section of the recess in the direction of the core line be formed in a V-shape. By making the cross-sectional shape of the concave portion V-shaped, the core wires can be more efficiently collected into the concave portion, and even if the number of the core wires inside the concave portion is slightly reduced, the compression rate of the core wire is not significantly affected. Can not be given.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a state in which a horn 10 of an ultrasonic welding machine according to the present invention is attached to an ultrasonic welding machine, and an anvil 11 is used for fixing a bus bar 12 which is a metal plate. The joining of the core wire S of the electric wire and the bus bar 12 by ultrasonic welding is performed by pressing the horn 10 of the ultrasonic welding machine against the core wire S placed on the bus bar 12 in the direction of the arrow Y in the drawing, and pressing X in the drawing. The horn 10 is vibrated in the direction. In many cases, a twisted wire or a flat cable is used as an electric wire to be welded.
Consists of a number of bare wires.

2 (A), 2 (B) and 2 (C) show the tip of the horn 10. The horn 10 has a required thickness in the axial direction of the core wire to be welded, and has a flat pressing surface 10- on the lower surface. 1
Of the horn 10 at the center of the
Recess 10a continuously from one end face 10c to the other end face 10d.
Is provided. The shape of the concave portion 10a is formed such that the cross section in the core wire cross section direction becomes a V shape. The opening width of the recess 10a on the pressing surface 10-1 is
The flat horizontal surface 10b is set so as to be reliably formed on both sides of the horizontal surface 0a, and the surface of the horizontal surface 10b is knurled.

The V of the recess 10a in FIG.
The inclination angle K of the slope of the shape is such that even if the number of core wires S is slightly reduced during welding, the compression ratio of one of the joined core wires S is not significantly changed by the number of core wires S accommodated in the recess 10a. It is set in consideration of the diameter of the core wire.

When setting the shape of the recess 10a as described above, it is necessary to consider the cross-sectional area of the V-shape of the recess 10a. That is, the cross-sectional area of the V shape of the concave portion 10a is set to be smaller than the total cross-sectional area of all the core wires S, and when the core wires S are arranged in one step on the upper surface of the bus bar, the surplus does not rest on the bus bar. The total cross-sectional area of the core wire S and the cross-sectional area of the concave portion 10a are set in comparison with each other.
The pressing surface 10-1 of the horn 10 is formed as described above, and the contact area with the core wire is increased. In addition, the concave portion 1
The shape is not limited to the V shape of 0a, and may be, for example, a trapezoidal shape or a semicircular shape.

As shown in FIG. 3A, the core wire S is mounted on the upper surface of the bus bar 12 fixed on the anvil 11 by joining the core wire S by ultrasonic welding. At this time, the core wire S is placed at the center of the bus bar 12 and the centers of the bus bar 12 and the horn 10 are aligned.

As described above, the horn 10 is lowered in the direction of the arrow in the figure, and the core wire S is pressed against the entire lower surface of the pressing surface 10-1.
The core wire S is collected at the center depending on the shape, but as shown in FIG.
Spreads to both ends on the upper surface of the bus bar 12, and the horizontal surface 10b
It is pressed and pinched. Thus, the core wire S
Is securely sandwiched between the upper surfaces of the bus bars 12,
There is no protruding core wire. In this pressurized state, the core wire S is joined to the bus bar 12 by vibrating with ultrasonic waves.

As shown in FIG. 4, even when a core wire S 'from which several bare wires are missing than usual is joined, when the horn 10 is pressed against the core wire S', the inside of the concave portion 10a is formed. , The core wire S 'which cannot be filled overflows, but the core wire S'
, The number of overflows is small, and the busbar 12 extends only to the front of both ends. However, since the overflowing core wire S 'is also securely sandwiched between the horizontal surfaces 10b, the horizontal surface 1' can be maintained even under a pressurized state.
The core wire S 'and the bus bar 12 are joined by ultrasonic welding without the contact of the core wire S' with the upper surface of the bus bar 12 and the compression rate of the core wire S 'in the concave portion 10a.

[0018]

As is apparent from the above description, the core wire is securely inserted between the pressing surfaces of the horn of the ultrasonic welding machine, and at the same time, even if the number of core wires to be welded is reduced somewhat, the compressibility inside the recess is reduced. Since the fluctuation is suppressed, welding conditions are stabilized, and welding strength can be improved. Thereby, the difference in the welding strength of the welded product can be suppressed. Further, since the core wire that has protruded from the bus bar can be absorbed by the concave portion of the horn, the core wire can be prevented from protruding from the upper surface of the bus bar, and a short circuit can be eliminated.

Further, since the pressing surface of the horn presses the bus bar with the core wire interposed in a horizontal plane, the horn does not come into direct contact with the bus bar, so that the welding conditions can be stabilized, and the horn formed by the contact with the bus bar can be stabilized. Wear and breakage can be eliminated.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a horn of the present invention is attached to an ultrasonic welding machine.

FIG. 2 shows a horn of the present invention, (A) is a front view,
(B) is a side view, and (C) is a bottom view.

FIG. 3 shows a welding state by the horn of the present invention,
(A) is a schematic diagram before the horn is pressed, and (B) is a schematic diagram when the horn is pressed.

FIG. 4 is a schematic view showing a state in which the horn of the present invention is pressed against a welding state, in which the number of core wires to be welded is small.

5A and 5B show a welding state using a conventional dome-shaped horn, in which FIG. 5A is a schematic view before the horn is pressed, and FIG. 5B is a schematic view when the horn is pressed.

6A and 6B show a welding state using a conventional flat horn, in which FIG. 6A is a schematic diagram before the horn is pressed, and FIG. 6B is a schematic diagram when the horn is pressed.

FIG. 7 is a front view showing another conventional horn.

[Description of Signs] 1, 1 ', 1 ", 10 horn 2, 12 Bus bar 10a Recess 10b Horizontal plane 11 Anvil S Core wire

Claims (2)

[Claims] 1. A horn for an ultrasonic welding machine for joining a core wire of an electric wire to a metal plate, wherein the horn has a required thickness in the axial direction of the core wire, and the entire lower surface thereof is connected to the core wire of the electric wire. A pressing surface to be pressed, a recess smaller than the total cross-sectional area of all the core wires at the center of the pressing surface in the direction of the core wire cross section, and horizontal surfaces on both sides of the recess, and a core wire placed on the upper surface of the metal plate A horn of the ultrasonic welding machine, wherein the horn is pressed against a concave portion of the horn and a core wire overflowing from the concave portion is pressed against the horizontal surface. 2. The horn of an ultrasonic welding machine according to claim 1, wherein a cross section of the concave portion in a core line cross section direction is formed in a V shape.