Horn and ultrasonic joint device

Abstract

To provide a horn advantageous in suppressing attenuation of ultrasonic vibrations propagated in a plurality of objects to be joined.SOLUTION: A horn 10 has a knurl-shaped uneven part 10b formed of a plurality of projections 11 on a first end surface 10a. At least a pair of projections which are arranged symmetrically at both outermost ends along a vibration direction among the plurality of projections 11 are asymmetrical surface projections 11a, 11b. The asymmetrical surface projections 11a, 11b each have an angle value θb of an outside inclination angle smaller than an angle value θa of an inside inclination angle.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a horn and an ultrasonic bonding device. [Background technology]

[0002] Conventionally, there is an ultrasonic bonding device that applies ultrasonic vibration to a horn while multiple objects to be bonded are sandwiched between the horn and an anvil to bond the objects to be bonded. Patent Document 1 discloses a technology relating to an ultrasonic bonding device in which multiple objects to be bonded are assumed to be the core wires of multiple electric wires, and at least one of the opposing end faces of the horn and the anvil is provided with an uneven portion consisting of multiple protrusions with a triangular cross section aligned in the axial direction of the core wires. In general, the vibration of the horn propagates between the multiple objects to be bonded while being attenuated, and reaches the anvil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-110382 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the ultrasonic bonding device disclosed in Patent Document 1, the vibration of the horn is transmitted to the objects to be bonded by the multiple protrusions being caught on the objects to be bonded during the bonding operation. However, since the cross-sectional shape of all the protrusions included in the uneven portion is set to an isosceles triangle symmetrical with respect to the apex, depending on the setting of the apex angle of each protrusion, the angle of the reaction force acting on the objects to be bonded relative to the vibration direction of the horn becomes large. In this case, the vibration direction component of the reaction force acting on the objects to be bonded becomes small, and the force that pushes the objects to be bonded along the vibration direction when the horn vibrates is dispersed. Therefore, for example, when there are many objects to be bonded, it is possible that the attenuation of the vibration cannot be suppressed and the bonding between the objects to be bonded may become weak.

[0005] The present invention has been made in consideration of the problems inherent in the conventional techniques, and an object of the present invention is to provide a horn and an ultrasonic bonding device that are advantageous in suppressing attenuation of ultrasonic vibrations propagating through multiple objects to be bonded. [Means for solving the problem]

[0006] A first aspect of the present invention is a horn that applies ultrasonic vibrations to multiple objects to be joined that are sandwiched between an anvil and the horn, and joins them to each other. The horn has, on its end face that comes into contact with the objects to be joined, a knurl-shaped uneven portion consisting of a plurality of protrusions that each extend in a width direction perpendicular to the vibration direction of the horn. Of the multiple protrusions, at least a pair of protrusions that are arranged symmetrically to each other at the outermost ends of both sides in a direction along the vibration direction are asymmetrical surface protrusions, and the cross-sectional shape of the asymmetrical surface protrusions perpendicular to the width direction is a triangle with the apex of the asymmetrical surface protrusion as its apex. Of the two side surfaces of the asymmetrical surface protrusion, the inclination angle of one side surface that inclines toward the outside of the uneven portion is defined as the outer inclination angle, and the inclination angle of the other side surface that inclines toward the inside of the uneven portion is defined as the inner inclination angle, and the angle value of the outer inclination angle is smaller than the angle value of the inner inclination angle.

[0007] A second aspect of the present invention is an ultrasonic bonding device that bonds multiple objects to each other by applying ultrasonic vibrations from a horn to the multiple objects clamped between a horn and an anvil, wherein the horn is the horn according to the first aspect described above. Effect of the Invention

[0008] According to the present invention, it is possible to provide a horn and an ultrasonic bonding device that are advantageous in suppressing attenuation of ultrasonic vibrations propagating through a plurality of objects to be bonded. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a side view of the ultrasonic bonding device according to the first embodiment before a bonding operation. [Diagram 2] FIG. 1 is a perspective view of a horn according to a first embodiment. [Diagram 3]4 is a side view of a concave-convex portion of the horn according to the first embodiment. FIG. [Figure 4A] 3A to 3C are side views of the ultrasonic bonding device showing various aspects during a bonding operation. [Figure 4B] 4B is an enlarged view of the vicinity of the second asymmetric surface protrusion corresponding to part IVB in FIG. 4A. FIG. [Diagram 5] FIG. 11 is a side view of a concave-convex portion of the horn according to the second embodiment. [Figure 6] FIG. 11 is a side view of a concave-convex portion of the horn according to the third embodiment. [Figure 7] FIG. 13 is a side view of a concave-convex portion of a horn according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a horn and an ultrasonic bonding device including the horn according to each embodiment will be described in detail with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[0011] (First embodiment) Fig. 1 is a side view of an ultrasonic joining device 1 in a state prior to joining operation, assuming that conductors 121 at the ends of a plurality of electric wires with terminals 110 are objects to be joined. Note that in Fig. 1, only a horn 10 and an anvil 20 that clamp the plurality of conductors 121 are shown in cross section.

[0012] The ultrasonic bonding device 1 overlaps a plurality of objects to be bonded with each other, and bonds the objects to be bonded together by applying pressure to the objects in a direction to bring them closer to each other while applying ultrasonic vibration energy thereto.

[0013] In this embodiment, the multiple joining objects are three conductors 121 exposed at the end portions of three electric wires with terminals 110. The electric wires with terminals 110 include an electric wire 120 and a terminal fitting 130. The electric wires 120 are insulated electric wires including a conductor 121 and a coating portion 122 that covers the conductor 121. The conductor 121 is a core wire formed by twisting together wires made of a conductive metal material such as copper, copper alloy, aluminum, or aluminum alloy. The coating portion 122 is formed of a synthetic resin material having flexibility and electrical insulation. At the end portions of the electric wires 120, the coating portion 122 is removed to expose a part of the conductor 121. The terminal fitting 130 is crimped to one end of the electric wire 120 where the conductor 121 is exposed. The terminal fitting 130 is formed by processing a plate material made of a conductive metal material such as copper, copper alloy, aluminum, or aluminum alloy.

[0014] The ultrasonic bonding device 1 includes a horn 10, an anvil 20, a vibrator 30, and a pressure device 40. The horn 10 and the anvil 20 are disposed spaced apart from each other, and during a bonding operation, a plurality of conductors 121, which are objects to be bonded, are sandwiched between the opposing end faces. In this embodiment, the direction in which the horn 10 and the anvil 20 are spaced apart from each other is the up-down direction, which corresponds to the direction along the Z direction shown in each drawing.

[0015] Horn 10 is a block-shaped structure located below anvil 20. Horn 10 has a first end surface 10a that comes into contact with conductor 121 during a joining operation. The specific shape of horn 10 will be described in detail below.

[0016] The anvil 20 is a block-shaped structure located above the horn 10. The anvil 20 has a second end surface 20a that comes into contact with the conductor 121 during the joining operation. The opposing direction of the first end surface 10a of the horn 10 and the second end surface 20a of the anvil 20 is the direction along the Z direction, similar to the separation direction of the horn 10 and the anvil 20. Note that the second end surface 20a may have an uneven portion 20b formed thereon for making close contact with a part of the conductor 121.

[0017] The vibrator 30 is a driving source for vibrating the horn 10. The vibrator 30 is attached to the horn 10 in advance, and is vibrated by an oscillator (not shown) to apply ultrasonic vibrations along the vibration direction to the horn 10. In this embodiment, the vibration direction of the horn 10 is along one direction parallel to the horizontal plane, which corresponds to the direction along the X direction shown in each drawing.

[0018] The pressure device 40 is a drive source for applying a load to the anvil 20. During a joining operation, the pressure device 40 presses the anvil 20 against the horn 10 in the Z direction in a state in which the first end surface 10a and the second end surface 20a sandwich the multiple conductors 121.

[0019] Next, the specific shape of the horn 10 will be described.

[0020] Fig. 2 is a perspective view of horn 10 in which concave-convex portion 10b provided on first end surface 10a can be visually recognized. Fig. 3 is a side view of concave-convex portion 10b as viewed in the Y direction.

[0021] Hereinafter, the horizontal plane perpendicular to the Z direction is assumed to be the XY plane, the X direction along which the vibration direction VD (see Figure 3) of horn 10 runs is defined as the length direction of horn 10, and the Y direction perpendicular to the length direction is defined as the width direction of horn 10.

[0022] Horn 10 has knurled uneven portion 10b on first end surface 10a, in which multiple protrusions 11 each extending in the width direction are continuous in the length direction. Focusing on one protrusion 11, the cross-sectional shape of protrusion 11 cut by a virtual XZ plane perpendicular to the width direction is an isosceles triangle with apex 12 as a vertex and apex angle of angle θ. The length connecting two valleys 13 on opposite sides in the length direction is represented by protrusion width W. The height from valley 13 to apex 12 of adjacent protrusions 11 in the vertical direction is represented by protrusion height H.

[0023] Here, if the angle value θ set as the apex angle of the apex 12 is too large, the efficiency with which the horn 10 transmits vibration to the conductor 121 via each of the projections 11 may decrease. On the other hand, if the angle value θ is too small, each of the projections 11 may damage the conductor 121, or each of the projections 11 itself may become susceptible to wear. Therefore, it is desirable that the angle value θ set as the apex angle of the apex 12 be in the range of 60° to 160°. Furthermore, it is more desirable that the angle value θ be 140°.

[0024] In addition, when a center plane CP is defined as a plane that is parallel to the imaginary YZ plane and passes through the center position in the longitudinal direction on the first end face 10a, the multiple protrusions 11 are arranged symmetrically with respect to the center plane CP. In this embodiment, as an example, there are four protrusions 11. In this case, protrusion groups each consisting of two protrusions 11 are arranged symmetrically with respect to each other on one side and the other side in the longitudinal direction with respect to the center plane CP.

[0025] In this embodiment, the number of the protrusions 11 is an even number, and the protrusions 11 are arranged such that one valley 13 is located on the center plane CP. In contrast, the number of the protrusions 11 may be an odd number, and the protrusions 11 may be arranged such that one peak 12 is located on the center plane CP.

[0026] Furthermore, in the horn 10, among the multiple protrusions 11 included in the concave-convex portion 10b, at least a pair of protrusions arranged symmetrically with respect to each other at the outermost ends in the direction along the vibration direction are asymmetric surface protrusions. In this embodiment, the asymmetric surface protrusions are a first asymmetric surface protrusion 11a and a second asymmetric surface protrusion 11b, which have shapes symmetrical with respect to the center plane CP. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the apex of the asymmetric surface protrusion as its vertex.

[0027] Now, for comparison, looking again at one protrusion 11, protrusion 11 has a first side surface 14 that slopes from apex 12 to one side in the length direction, and a second side surface 15 that slopes from apex 12 to the other side in the length direction. Since the cross-sectional shape of protrusion 11 in the XZ plane is an isosceles triangle as described above, the inclination angle of first side surface 14 and the inclination angle of second side surface 15 are the same as each other at an angle θc (see FIG. 4B). In other words, protrusion 11 can be said to be a symmetrical protrusion having first side surface 14 and second side surface 15 that are symmetrical to each other with respect to apex 12.

[0028] In contrast, the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b have different inclination angles of the side surfaces inclined toward the inside of the uneven portion 10b and the side surfaces inclined toward the outside of the uneven portion 10b. Hereinafter, the inclination angle of the side surfaces inclined toward the inside of the uneven portion 10b is defined as the inner inclination angle. Meanwhile, the inclination angle of the side surfaces inclined toward the outside of the uneven portion 10b is defined as the outer inclination angle. Hereinafter, the inner side of the uneven portion 10b is, in other words, the side on which the center plane CP is set. The outer side of the uneven portion 10b is, in other words, the side opposite to the side on which the center plane CP is set. In the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b, the outer inclination angle is smaller than the inner inclination angle. Moreover, the sum of the value of the inner inclination angle and the value of the outer inclination angle is the same as the angle value θ of the apex angle of the protrusion 11.

[0029] Specifically, the first asymmetric surface protrusion 11a has a first side surface 14a inclined toward the outside of the uneven portion 10b and a second side surface 15a inclined toward the inside of the uneven portion 10b. The position of the apex 12 of the first asymmetric surface protrusion 11a is assumed to be the position of the apex 12 when a virtual protrusion 11v of the same shape is provided continuously to the multiple protrusions 11 at the position where the first asymmetric surface protrusion 11a is provided, as shown in FIG. 3. The angle value θb of the outer inclination angle regarding the first side surface 14a is smaller than the angle value θa of the inner inclination angle regarding the second side surface 15a. The sum of the angle value θa and the angle value θb is the angle value θ. Furthermore, by setting the inner inclination angle here to the angle value θa, the area of ​​the first side surface 14 of the adjacent protrusion 11 to which the end of the second side surface 15a is continuous becomes smaller than the area of ​​the first side surface 14 of the other protrusions 11.

[0030] Similarly, the second asymmetric surface protrusion 11b has a first side surface 14b inclined toward the inside of the uneven portion 10b and a second side surface 15b inclined toward the outside of the uneven portion 10b. The position of the apex 12 of the second asymmetric surface protrusion 11b is also assumed to be the position of the apex 12 when a virtual protrusion 11v of the same shape is provided continuously to the multiple protrusions 11 at the position where the second asymmetric surface protrusion 11b is provided, as shown in FIG. 3. The angle value θb of the outer inclination angle regarding the second side surface 15b is smaller than the angle value θa of the inner inclination angle regarding the first side surface 14b. Also, the sum of the angle value θa and the angle value θb is the angle value θ, similar to the first asymmetric surface protrusion 11a. Furthermore, by setting the inner inclination angle regarding the first side surface 14b to the angle value θa, the area of ​​the second side surface 15 of the adjacent protrusion 11 to which the end of the first side surface 14b is continuous becomes smaller than the area of ​​the second side surface 15 of the other protrusions 11.

[0031] That is, the first side surface 14a of the first asymmetric surface protrusion 11a and the second side surface 15b of the second asymmetric surface protrusion 11b have shapes symmetrical to each other with respect to the central plane CP. Similarly, the second side surface 15a of the first asymmetric surface protrusion 11a and the first side surface 14b of the second asymmetric surface protrusion 11b have shapes symmetrical to each other with respect to the central plane CP.

[0032] Next, the operation of the ultrasonic bonding device 1 employing the horn 10 will be described.

[0033] Fig. 4A is a side view of the ultrasonic bonding device 1 showing various aspects during a bonding operation, and Fig. 4B is an enlarged view of the vicinity of the second asymmetric surface projection 11b, which corresponds to the portion IVB in Fig. 4A.

[0034] First, as shown in FIG. 1, in the initial state of the joining operation, three conductors 121 that have been exposed in advance are arranged between the first end surface 10a of the horn 10 and the second end surface 20a of the anvil 20. From this initial state, the ultrasonic joining device 1 restricts the width direction along the Y direction for the three conductors 121 using a separate member, and as shown in FIG. 4A, the conductors 121 are joined together by applying ultrasonic vibrations from the horn 10 while applying a load P from the anvil 20. In the example of FIG. 4A, the three conductors 121 are arranged in the up-down direction. Hereinafter, the conductor 121 arranged at the bottom is referred to as the first conductor 121a, the conductor 121 arranged at the middle is referred to as the second conductor 121b, and the conductor 121 arranged at the top is referred to as the third conductor 121c. The uneven portion 10b formed on the first end face 10a contacts the first conductor 121a, and the uneven portion 20b formed on the second end face 20a contacts the third conductor 121c.

[0035] During the joining operation, the vibration of horn 10 propagates between the three conductors 121 while being attenuated, as shown by the attenuation direction Dm in Fig. 4A, and reaches anvil 20. Therefore, horn 10 has uneven portion 10b, a part of which bites into first conductor 121a, in order to suppress the attenuation of the vibration and transmit the vibration to conductor 121 more efficiently.

[0036] Here, as a comparative example, a case is assumed in which a virtual protrusion 11v having the same shape as the other protrusions 11 is provided on the uneven portion 10b of the horn 10, instead of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b. In FIG. 4B, as an example, the virtual protrusion 11v replacing the second asymmetric surface protrusion 11b is drawn by a two-dot chain line. Referring to FIG. 4B, the angle value of the inclination angle of the second side surface 15 of the virtual protrusion 11v is the same angle value θc as the inclination angle of the second side surface 15 of the other protrusions 11. Then, when the horn 10 vibrates and the virtual protrusion 11v bites into the first conductor 121a, the reaction force acting on the first conductor 121a is directed relatively upward outside the uneven portion 10b, as represented by the two-dot chain arrow in FIG. 4B.

[0037] In contrast, in this embodiment, the uneven portion 10b of the horn 10 has a first asymmetric surface protrusion 11a and a second asymmetric surface protrusion 11b. Here, when focusing on the second asymmetric surface protrusion 11b to refer to FIG. 4B, as described above, the angle value θb of the outer inclination angle with respect to the second side surface 15b is smaller than the angle value θa of the inner inclination angle with respect to the first side surface 14b. In addition, the sum of the angle value θa and the angle value θb is the angle value θ of the apex angle of the protrusion 11. In other words, the angle value θb of the outer inclination angle with respect to the second side surface 15b is smaller than the angle value θc of the inclination angle of the second side surface 15 of the protrusion 11. Therefore, as shown in FIG. 4B, the reaction force acting on the first conductor 121a due to the second asymmetric surface protrusion 11b biting into the first conductor 121a is directed toward the outside of the uneven portion 10b, as represented by the hollow arrow. However, the reaction force applied by second asymmetrical surface protrusion 11b is directed in a direction closer to the horizontal direction than in the case of imaginary protrusion 11v. Therefore, when second asymmetrical surface protrusion 11b is present, the vibration direction component of the reaction force is larger than when imaginary protrusion 11v is present, so that the vibration of horn 10 is transmitted over a wider range between three conductors 121.

[0038] In addition, in the first asymmetric surface protrusion 11a as well, the outward inclination angle with respect to the first side surface 14a is set to angle value θb, so that the vibration of the horn 10 is transmitted between the three conductors 121 over a wider range.

[0039] On the other hand, if the apex angles of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b are set too small, the first conductor 121a in contact with the first asymmetric surface protrusion 11a may be easily cut, or each of the asymmetric surface protrusions may be easily worn, which is undesirable. Therefore, in this embodiment, the outer inclination angle is set to an angle value θb smaller than the angle value θc, and the inner inclination angle is set to an angle value θa larger than the angle value θc. By setting the inclination angles of each side in this manner, the apex angles of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b are prevented from becoming excessively small.

[0040] Next, the effects of the horn 10 and the ultrasonic bonding device 1 in which the horn 10 is used will be described.

[0041] The horn 10 applies ultrasonic vibrations to a plurality of objects to be joined, such as conductors 121, sandwiched between the horn 10 and the anvil 20, to join them together. The horn 10 has a knurled uneven portion 10b consisting of a plurality of protrusions 11 each extending in a width direction perpendicular to the vibration direction of the horn 10, on a first end surface 10a that contacts the objects to be joined. At least a pair of protrusions 11 among the plurality of protrusions 11, which are arranged symmetrically with each other at the outermost ends of both sides in a direction along the vibration direction, are asymmetric surface protrusions. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the apex of the asymmetric surface protrusion as the apex. Of the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface that inclines toward the outside of the uneven portion 10b is defined as the outer inclination angle, and the inclination angle of the other side surface that inclines toward the inside of the uneven portion 10b is defined as the inner inclination angle. At this time, the angle value θb of the outer inclination angle is smaller than the angle value θa of the inner inclination angle.

[0042] Moreover, the ultrasonic bonding apparatus 1 bonds a plurality of objects to each other by applying ultrasonic vibrations from the horn to the objects sandwiched between the horn and the anvil 20. Here, the horn is the above-mentioned horn 10.

[0043] Here, in the above example, the vibration direction of the horn 10 corresponds to the direction along the X direction. In the above example, the width direction of the horn 10 corresponds to the direction along the Y direction. In the above example, the pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b. In the first asymmetric surface protrusion 11a, the side surface that defines the outer inclination angle is the first side surface 14a, and the side surface that defines the inner inclination angle is the second side surface 15a. In the second asymmetric surface protrusion 11b, the side surface that defines the outer inclination angle is the second side surface 15b, and the side surface that defines the inner inclination angle is the first side surface 14b.

[0044] The horn 10 has a knurl-shaped uneven portion 10b on the first end surface 10a that contacts the objects to be joined. Here, among the multiple protrusions 11 that constitute the uneven portion 10b, at least a pair of protrusions that are arranged symmetrically with each other at the outermost ends of both sides in the direction along the vibration direction are asymmetric surface protrusions in which the angle value θa of the inner inclination angle and the angle value θb of the outer inclination angle are set to satisfy the above-mentioned condition. Therefore, as described above, according to the horn 10 in which the uneven portion 10b includes the asymmetric surface protrusions, the vibration direction component of the reaction force applied to the objects to be joined can be made larger than that of the comparative horn in which the uneven portion 10b does not include the asymmetric surface protrusions. Therefore, the vibration of the horn 10 can be transmitted to a wider range between the multiple objects to be joined.

[0045] Generally, when there are many objects to be joined, it is expected that the vibration of the horn will be attenuated to a large extent, resulting in a weak bond between the objects to be joined. In contrast, ultrasonic joining using the horn 10 according to this embodiment can efficiently transmit the vibration of the horn 10 to the objects to be joined, which is advantageous even when there are many objects to be joined.

[0046] As described above, according to the present embodiment, it is possible to provide a horn 10 and an ultrasonic bonding apparatus 1 that are advantageous in suppressing attenuation of ultrasonic vibrations propagating through a plurality of objects to be bonded.

[0047] Furthermore, in horn 10, among the plurality of protrusions 11, protrusions 11 that are not asymmetrical surface protrusions may have a cross-sectional shape perpendicular to the width direction that is an isosceles triangle with apex 12 of protrusion 11 as the vertex.

[0048] According to this horn 10, among the multiple protrusions 11, the protrusions 11 that are not asymmetrical surface protrusions have a simple cross-sectional shape, particularly perpendicular to the width direction, and can therefore be set in accordance with the shape of the protrusions provided on conventional horns.

[0049] In horn 10, the sum of the angle value θb of the outer inclination angle and the angle value θa of the inner inclination angle may be the same as the angle value θ of the apex angle of protrusion 11 that is not an asymmetric surface protrusion.

[0050] With this horn 10, since the outer inclination angle is set to a relatively small angle value θb and the inner inclination angle is set to a relatively large angle value θa, it is possible to prevent the apex angle of the asymmetrical surface protrusion from becoming excessively small. Therefore, it is possible to prevent the shape of the asymmetrical surface protrusion from damaging the joining object with which the uneven portion 10b comes into contact, or from making the asymmetrical surface protrusion itself more susceptible to wear.

[0051] In horn 10, angle value θ set as the apex angle of protrusion 11 may be in the range of 60° to 160°. More preferably, angle value θ set as the apex angle of protrusion 11 may be 140°.

[0052] As described above, if the angle value θ is too large, the efficiency with which horn 10 transmits vibration to conductor 121 via each protrusion 11 may decrease. On the other hand, if the angle value θ is too small, each protrusion 11 may damage the objects to be joined. In contrast, with this horn 10, the angle value θ is set within the above range or to a specific value, making it possible to avoid these undesirable phenomena in advance.

[0053] Second embodiment FIG. 5 is a side view of a concave-convex portion 50b of a horn 50 according to the second embodiment as viewed in the Y direction.

[0054] First, the horn 50, like the horn 10 according to the first embodiment, applies ultrasonic vibration to a plurality of objects to be joined that are sandwiched between the horn 50 and the anvil 20, thereby joining the objects together. On the other hand, the horn 50 has a knurl-shaped uneven portion 50b consisting of a plurality of protrusions 51 each extending in a width direction perpendicular to the vibration direction of the horn 50, on a first end surface 50a that contacts the objects to be joined, instead of the uneven portion 10b provided on the horn 10. At least a pair of protrusions among the plurality of protrusions 51 that are symmetrically arranged on the outermost ends of both sides in the direction along the vibration direction are asymmetric surface protrusions. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the apex of the asymmetric surface protrusion as the apex. Of the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface that is inclined toward the outside of the uneven portion 50b is defined as the outer inclination angle, and the inclination angle of the other side surface that is inclined toward the inside of the uneven portion 50b is defined as the inner inclination angle. At this time, the angle value θb of the outer tilt angle is smaller than the angle value θa of the inner tilt angle.

[0055] Here, in the above example, the vibration direction of the horn 50 corresponds to the direction along the X direction. In the above example, the width direction of the horn 50 corresponds to the direction along the Y direction. In the above example, the pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 51a and the second asymmetric surface protrusion 51b. In the first asymmetric surface protrusion 51a, the side surface that defines the outer inclination angle is the first side surface 54a, and the side surface that defines the inner inclination angle is the second side surface 55a. In the second asymmetric surface protrusion 51b, the side surface that defines the outer inclination angle is the second side surface 55b, and the side surface that defines the inner inclination angle is the first side surface 54b.

[0056] Moreover, the ultrasonic bonding apparatus 1 bonds a plurality of objects to each other by applying ultrasonic vibrations from the horn to the objects sandwiched between the horn and the anvil 20. Here, the horn is the above-mentioned horn 50.

[0057] In other words, the horn 50 and the ultrasonic bonding device 1 including the horn 50 provide the same effects as those of the first embodiment.

[0058] In horn 50, first side surface 54a of first asymmetric surface protrusion 51a facing outward of uneven portion 50b may be perpendicular to first end face 50a. Similarly, second side surface 55b of second asymmetric surface protrusion 51b facing outward of uneven portion 50b may be perpendicular to first end face 50a.

[0059] According to this horn 50, the apex angles of the first asymmetric surface projection 51a and the second asymmetric surface projection 51b are defined only by the inner inclination angle, so that the shape is sharper than that of the first embodiment. Therefore, the asymmetric surface projection is more likely to catch on the object to be joined, which is advantageous when it is desired to increase the vibration direction component of the reaction force applied to the object to be joined. The angle value of the inner inclination angle may be the same as the angle value θa of the inner inclination angle in the first embodiment, for example.

[0060] Third embodiment FIG. 6 is a side view of a concave-convex portion 60b of a horn 60 according to the third embodiment as viewed in the Y direction.

[0061] First, the horn 60, like the horn 10 according to the first embodiment, applies ultrasonic vibration to a plurality of objects to be joined that are sandwiched between the horn 60 and the anvil 20, thereby joining the objects together. On the other hand, the horn 60 has a knurl-shaped uneven portion 60b consisting of a plurality of protrusions 61 each extending in a width direction perpendicular to the vibration direction of the horn 60, on a first end surface 60a that contacts the objects to be joined, instead of the uneven portion 10b provided on the horn 10. At least a pair of protrusions among the plurality of protrusions 61 that are symmetrically arranged on the outermost ends of both sides in the direction along the vibration direction are asymmetric surface protrusions. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the apex of the asymmetric surface protrusion as the apex. Of the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface that is inclined toward the outside of the uneven portion 60b is defined as the outer inclination angle, and the inclination angle of the other side surface that is inclined toward the inside of the uneven portion 60b is defined as the inner inclination angle. At this time, the angle value θ1b of the outer inclination angle is smaller than the angle value θ1a of the inner inclination angle.

[0062] Here, in the above example, the vibration direction of the horn 60 corresponds to the direction along the X direction. In the above example, the width direction of the horn 60 corresponds to the direction along the Y direction. In the above example, the pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 61a and the second asymmetric surface protrusion 61b. In the first asymmetric surface protrusion 61a, the side surface that defines the outer inclination angle is the first side surface 64a, and the side surface that defines the inner inclination angle is the second side surface 65a. In the second asymmetric surface protrusion 61b, the side surface that defines the outer inclination angle is the second side surface 65b, and the side surface that defines the inner inclination angle is the first side surface 64b.

[0063] Moreover, the ultrasonic bonding apparatus 1 bonds a plurality of objects to each other by applying ultrasonic vibrations from the horn to the objects sandwiched between the horn and the anvil 20. Here, the horn is the above-mentioned horn 60.

[0064] In other words, the horn 60 and the ultrasonic bonding device 1 including the horn 60 provide the same effects as those of the first embodiment.

[0065] In the horn 60, the sum θ1 of the angle value θ1b of the outer inclination angle and the angle value θ1a of the inner inclination angle may be greater than the angle value θ of the apex angle of the protrusion 61 that is not an asymmetric surface protrusion.

[0066] According to this horn 60, the apex angle of the asymmetrical surface protrusion is set larger than that of the horn 10 of the first embodiment, which is advantageous in cases where, for example, it is desired to prioritize avoiding damage to the object to be joined that comes into contact with the asymmetrical surface protrusion, or wear of the asymmetrical surface protrusion itself.

[0067] (Fourth embodiment) FIG. 7 is a side view of the concave-convex portion 70b of the horn 70 according to the fourth embodiment as viewed in the Y direction.

[0068] The horn 70, like the horn 10 according to the first embodiment, applies ultrasonic vibrations to a plurality of objects to be joined that are sandwiched between the horn 70 and the anvil 20, thereby joining them together. On the other hand, instead of the uneven portion 10b provided on the horn 10, the horn 70 has a knurl-shaped uneven portion 70b consisting of a plurality of protrusions that each extend in a width direction perpendicular to the vibration direction of the horn 70 on a first end surface 70a that contacts the objects to be joined. At least a pair of protrusions among the plurality of protrusions that are symmetrically arranged at the outermost ends of both sides in the direction along the vibration direction are asymmetric surface protrusions. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the apex of the asymmetric surface protrusion as the apex. Of the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface that is inclined toward the outside of the uneven portion 70b is defined as the outer inclination angle, and the inclination angle of the other side surface that is inclined toward the inside of the uneven portion 70b is defined as the inner inclination angle. At this time, the angle value θb of the outer tilt angle is smaller than the angle value θa of the inner tilt angle.

[0069] Here, in the above example, the vibration direction of the horn 70 corresponds to the direction along the X direction. In the above example, the width direction of the horn 70 corresponds to the direction along the Y direction. In the above example, the pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 71a and the second asymmetric surface protrusion 71b. In the first asymmetric surface protrusion 71a, the side surface that defines the outer inclination angle is the first side surface 74a, and the side surface that defines the inner inclination angle is the second side surface 75a. In the second asymmetric surface protrusion 71b, the side surface that defines the outer inclination angle is the second side surface 75b, and the side surface that defines the inner inclination angle is the first side surface 74b.

[0070] Moreover, the ultrasonic bonding apparatus 1 bonds a plurality of objects to each other by applying ultrasonic vibrations from the horn to the objects sandwiched between the horn and the anvil 20. Here, the horn is the above-mentioned horn 70.

[0071] In other words, the horn 70 and the ultrasonic bonding device 1 including the horn 70 provide the same effects as those of the first embodiment.

[0072] Here, according to the above-mentioned definition of the horn 70, among the multiple protrusions, at least a pair of protrusions arranged symmetrically with each other at the outermost ends on both sides in the direction along the vibration direction may be asymmetric surface protrusions. That is, as shown in FIG. 7, all of the multiple protrusions may be asymmetric surface protrusions. In this case, with respect to the central plane CP, all of the protrusions 11 on one side in the length direction are first asymmetric surface protrusions 71a, and all of the protrusions 11 on the other side in the length direction are second asymmetric surface protrusions 71b. Each of the first asymmetric surface protrusions 71a and each of the second asymmetric surface protrusions 71b have a shape symmetrical with respect to the central plane CP.

[0073] Compared with the horn 10 of the first embodiment, this horn 70 has more asymmetric surface protrusions whose outer inclination angle is set to a relatively small angle value θb, which is advantageous, for example, when it is desired to transmit the vibration of the horn 70 over a wider range between multiple objects to be joined.

[0074] In each of the above embodiments, the multiple objects to be joined are all conductors 121, which are the core wires of electric wires 120, but for example, at least one of the multiple objects to be joined may be a plate material such as a metal plate.

[0075] Although the embodiments have been described above, the embodiments are not limited to these, and various modifications are possible within the scope of the gist of the embodiments. [Explanation of symbols]

[0076] 10,50,60,70 Horn 10a, 50a, 60a, 70a First end face 10b,50b,60b,70b Uneven part 11,51,61 protrusion 11a, 51a, 61a, 71a First asymmetric surface protrusion 11b, 51b, 61b, 71b Second asymmetric surface protrusion 14,14a,14b,54a,54b,64a,64b,74a,74b 1st side 15,15a,15b,55a,55b,65a,65b,75a,75b 2nd side 20 Anvil 121 Conductor

Claims

1. A horn that applies ultrasonic vibrations to a plurality of objects to be joined that are sandwiched between the horn and an anvil, and joins the objects to each other, The end surface that comes into contact with the workpiece has a knurl-shaped uneven portion that is made up of a plurality of protrusions that each extend in a width direction perpendicular to the vibration direction of the horn, Among the plurality of protrusions, at least a pair of protrusions arranged symmetrically to each other at the outermost ends of both sides in a direction along the vibration direction are asymmetric surface protrusions, a cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle having an apex at the apex of the asymmetric surface protrusion, Of the two side surfaces of the asymmetric surface protrusion, the inclination angle of one of the side surfaces inclined toward the outside of the uneven portion is defined as an outer inclination angle, and the inclination angle of the other side surface inclined toward the inside of the uneven portion is defined as an inner inclination angle. The angle value of the outer tilt angle is less than the angle value of the inner tilt angle.

2. 2. The horn according to claim 1, wherein a cross-sectional shape perpendicular to the width direction of one of the plurality of protrusions that is not an asymmetric surface protrusion is an isosceles triangle having an apex at the top of the protrusion as a vertex.

3. 3. The horn of claim 2, wherein the sum of the angle value of the outer cant angle and the angle value of the inner cant angle is the same as the angle value of an apex angle of the protrusion that is not the asymmetric face protrusion.

4. 3. The horn of claim 2, wherein the sum of the angle value of the outer slope angle and the angle value of the inner slope angle is greater than the angle value of an apex angle of the protrusion that is not the asymmetric face protrusion.

5. The horn according to claim 3 or 4, wherein the angle value set for the apex angle of the projection is in the range of 60° to 160°.

6. The horn of claim 5 , wherein the angle value established for the apex angle of the protrusion is 140°.

7. The horn according to claim 1 or 2, wherein the side surface of the asymmetrical surface projection that faces outward from the uneven portion is perpendicular to the end face.

8. An ultrasonic bonding apparatus that bonds a plurality of objects to be bonded together by applying ultrasonic vibrations from the horn to the plurality of objects to be bonded that are sandwiched between a horn and an anvil, The ultrasonic bonding apparatus according to claim 1 or 2, wherein the horn is a horn.

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