Welding head and ultrasonic adapter

Abstract

The invention relates to a welding head and an ultrasonic adapter. The horn has a knurled concave-convex portion formed by a plurality of protrusions and formed on the first end face. Among the plurality of protrusions, at least a pair of protrusions symmetrically provided at two outermost ends in a direction along the vibration direction are asymmetrical surface protrusions. In each asymmetric surface protrusion, an angle value of the outer tilt angle is smaller than an angle value of the inner tilt angle. The welding head and the ultrasonic adapter of the present disclosure are advantageous for suppressing attenuation of ultrasonic vibration propagating to a plurality of objects to be joined.

Description

Technical Field

[0001] The present disclosure relates to a welding head and an ultrasonic bonder. Background Art

[0002] An ultrasonic bonder is generally known, which applies ultrasonic vibration to the welding head while clamping multiple objects to be bonded between the welding head and the anvil, so as to bond the objects to be bonded to each other. Patent document JP2008-110382A discloses a technology related to an ultrasonic bonder, wherein it is assumed that the multiple objects to be bonded are core wires in multiple electric wires, and at least one of the end faces facing each other of the welding head and the anvil has a concave-convex portion formed by a plurality of protrusions thereon, each of which has a triangular cross-section and is arranged in a row with each other in the axial direction of the core wire. Generally, the vibration from the welding head propagates between the multiple objects to be bonded while being attenuated, and reaches the anvil. Summary of the invention

[0003] In the ultrasonic bonder disclosed in patent document JP2008-110382A, since a plurality of protrusions are stuck on the objects to be bonded during the bonding operation, the vibration from the welding head is transmitted to the objects to be bonded. However, the cross-sectional shape of all the protrusions contained in the concave-convex portion is set to an isosceles triangle, which is linearly symmetrical relative to the vertices of the triangle. Therefore, according to the selection of the vertex angle of each protrusion, the angle of the reaction force applied to the objects to be bonded relative to the vibration direction of the welding head becomes larger. In this case, the vibration direction component of the reaction force applied to the objects to be bonded becomes smaller, and when the welding head vibrates, the force for pressing the objects to be bonded in the vibration direction is dispersed. Therefore, for example, when the number of objects to be bonded is large, the attenuation of the vibration cannot be suppressed, and the bonding between the objects to be bonded may be weakened.

[0004] An object of the present invention is to provide a welding head and an ultrasonic welder which are advantageous in suppressing the attenuation of ultrasonic vibrations propagating to a plurality of objects to be welded.

[0005] A first aspect of the present invention provides a welding head, which applies ultrasonic vibration to a plurality of objects to be joined clamped between an anvil and the welding head to join the objects to be joined to each other, the welding head comprising: a knurled shaped concave-convex portion, the concave-convex portion being formed by a plurality of protrusions, each of the protrusions extending in a width direction perpendicular to the vibration direction of the welding head, and the concave-convex portion being formed on an end face in contact with one of the objects to be joined, wherein, among the plurality of protrusions, at least a pair of protrusions symmetrically arranged at the two outermost ends in the direction along the vibration direction are asymmetric surface protrusions, the cross-sectional shape of each asymmetric surface protrusion perpendicular to the width direction is a triangle with the top of each asymmetric surface protrusion as the vertex, and among the two side surfaces of each asymmetric surface protrusion, the inclination angle of one of the two side surfaces inclined toward the outer side of the concave-convex portion is defined as an outer inclination angle, and the inclination angle of the other of the two side surfaces inclined toward the inner side of the concave-convex portion is defined as an inner inclination angle, and the angle value of the outer inclination angle is smaller than the angle value of the inner inclination angle.

[0006] A second aspect of the present invention provides an ultrasonic bonder that applies ultrasonic vibrations from a horn to a plurality of objects to be bonded sandwiched between the horn and an anvil to bond the plurality of objects to be bonded to each other, wherein the horn is the horn according to the first aspect.

[0007] According to the above configuration, it is possible to provide a horn and an ultrasonic bonder that are advantageous in suppressing attenuation of ultrasonic vibrations propagating to a plurality of objects to be bonded. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a side view of the ultrasonic bonder according to the first embodiment before performing a bonding operation.

[0009] Figure 2 is a perspective view of a welding head according to the first embodiment.

[0010] Figure 3 is a side view of the concavo-convex portion in the welding head according to the first embodiment.

[0011] Figure 4A 1 is a side view of the ultrasonic bonder showing various states when performing a bonding operation.

[0012] Figure 4B is with Figure 4A An enlarged view of the vicinity of the second asymmetric surface protrusion corresponding to part IVB.

[0013] Figure 5 1 is a side view of a concavo-convex portion in a welding head according to a second embodiment.

[0014] Figure 6 1 is a side view of a concavo-convex portion in a welding head according to a third embodiment.

[0015] Figure 7 1 is a side view of a concavo-convex portion in a welding head according to a fourth embodiment. DETAILED DESCRIPTION

[0016] A horn and an ultrasonic bonder including the horn according to each embodiment will be described in detail below with reference to the accompanying drawings. For convenience of explanation, the dimensional ratios of the drawings are exaggerated and may be different from the actual ratios.

[0017] (First embodiment)

[0018] Figure 1 1 is a side view of the ultrasonic bonder 1 before the bonding operation is performed when it is assumed that all the conductors 121 at the ends of the plurality of terminal-equipped electric wires 110 are objects to be bonded. Figure 1 Also shown is a cross-sectional representation of the horn 10 and anvil 20 sandwiching a plurality of conductors 121 .

[0019] In the ultrasonic bonder 1, a plurality of objects to be bonded overlap each other. The objects to be bonded are bonded by applying ultrasonic vibration energy while applying pressure in a direction in which the plurality of objects to be bonded are brought close to each other.

[0020] In the present embodiment, the plurality of objects to be joined are three conductors 121 exposed at the ends of three wires 110 equipped with terminals. The wire 110 equipped with terminals includes a wire 120 and a terminal fitting 130. The wire 120 is an insulated wire having a conductor 121 and a coating 122 covering the periphery of the conductor 121. The conductor 121 is a core wire obtained by twisting element wires made of a conductive metal material such as copper, copper alloy, aluminum or aluminum alloy. The coating 122 is formed of a synthetic resin material having flexibility and electrical insulation. At the end of the wire 120, the coating 122 is removed to expose a portion of the conductor 121. The terminal fitting 130 is crimped to the exposed end of the conductor 121 of the wire 120. For example, the terminal fitting 130 is formed by processing a plate made of a conductive metal material such as copper, copper alloy, aluminum or aluminum alloy.

[0021] The ultrasonic bonder 1 includes a horn 10, an anvil 20, a vibrator 30, and a pressurizing device 40. The horn 10 and the anvil 20 are arranged to be separated from each other. When performing a bonding operation, the horn 10 and the anvil 20 sandwich the conductors 121, which are multiple objects to be bonded, between the end faces facing each other. In the present embodiment, the separation direction between the horn 10 and the anvil 20 is the up-down direction, and the up-down direction corresponds to the direction along the Z direction shown in the respective figures.

[0022] The welding head 10 is a block-shaped structure located below the anvil 20. The welding head 10 has a first end surface 10a that contacts the conductor 121 when performing a bonding operation. The specific shape of the welding head 10 will be described in detail below.

[0023] The anvil 20 is a block-shaped structure located above the welding head 10. The anvil 20 has a second end surface 20a that contacts the conductor 121 when performing a joining operation. The direction in which the first end surface 10a of the welding head 10 and the second end surface 20a of the anvil 20 face each other is a direction along the Z direction, similar to the separation direction between the welding head 10 and the anvil 20. A concave-convex portion 20b may be formed on the second end surface 20a for close contact with a portion of the conductor 121.

[0024] The vibrator 30 is a driving source for vibrating the welding head 10. The vibrator 30 is pre-installed on the welding head 10, and due to being vibrated by an oscillator (not shown), the vibrator 30 applies ultrasonic vibration to the welding head 10 in a vibration direction. In the present embodiment, the vibration direction of the welding head 10 is along a direction parallel to the horizontal plane, and corresponds to the direction along the X direction shown in the respective figures.

[0025] The pressurizing device 40 is a driving source for applying a load to the anvil 20. During the bonding operation, the pressurizing device 40 presses the anvil 20 toward the horn 10 in the Z direction while the first and second end surfaces 10a and 20a sandwich the plurality of conductors 121.

[0026] Next, the specific shape of the welding head 10 will be described.

[0027] Figure 2 1 is a perspective view of the welding head 10 , in which the concavo-convex portion 10 b formed on the first end surface 10 a can be visually recognized. Figure 3 It is a side view of the concavo-convex part 10b when viewed in the Y direction.

[0028] In the following, it is assumed that the horizontal plane perpendicular to the Z direction is the XY plane. Figure 3 ) is defined as the length direction of the welding head 10, and the Y direction perpendicular to the length direction is defined as the width direction of the welding head 10.

[0029] The welding head 10 has a knurled concavoconvex portion 10b on its first end face 10a, wherein a plurality of protrusions 11 extending in the width direction are continuous in the length direction. Focusing on one protrusion 11, the cross-sectional shape of the protrusion 11 obtained by cutting the protrusion 11 along a plane parallel to the imaginary XZ plane and perpendicular to the width direction is an isosceles triangle with the top 12 as the vertex, and the vertex has an angle θ. The length obtained by connecting two valleys 13 disposed on opposite sides with a protrusion therebetween in the length direction is represented by the protrusion width W. The height in the up-down direction from the valley 13 to the top 12 between two adjacent protrusions 11 is represented by the protrusion height H.

[0030] If the angle value θ defined as the vertex angle of the top 12 is too large, there is a risk that the efficiency of the welding head 10 transmitting vibration to the conductor 121 through each protrusion 11 is deteriorated. Meanwhile, if the angle value θ is too small, each protrusion 11 may damage the conductor 121, or each protrusion 11 itself may be easily worn. Therefore, preferably, the angle value θ set as the value of the vertex angle of the top 12 is in the range of 60 degrees to 160 degrees. Furthermore, more preferably, the angle value θ is 140 degrees.

[0031] In addition, it is assumed that the first end surface 10a has a center plane CP, which is defined as a plane parallel to the YZ plane and passes through the center position in the length direction. In the above case, the plurality of protrusions 11 are arranged symmetrically with the center plane CP as the center. In the present embodiment, as an example, the number of protrusions 11 is four. In this case, a protrusion group formed by two protrusions 11 is arranged symmetrically on one side and the other side with the center plane CP as the center in the length direction.

[0032] In this embodiment, the number of the plurality of protrusions 11 is an even number, and the plurality of protrusions 11 are arranged so that one valley 13 is located at the center plane CP. In contrast, the number of the plurality of protrusions 11 may be an odd number, and the plurality of protrusions 11 may be arranged so that one top 12 is located at the center plane CP.

[0033] In addition, among the plurality of protrusions 11 included in the concavo-convex portion 10b of the welding head 10, at least a pair of protrusions symmetrically arranged at the two outermost ends in the direction along the vibration direction are asymmetric surface protrusions. The asymmetric surface protrusions in this embodiment are first asymmetric surface protrusions 11a and second asymmetric surface protrusions 11b whose shapes are symmetrical to each other with the center plane CP as the center. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the top of the asymmetric surface protrusion as the vertex.

[0034] Here, we again focus on one protrusion 11 for comparison. The protrusion 11 has a first side surface 14 that is inclined from the top 12 to one side in the length direction and a second side surface 15 that is inclined from the top 12 to the other side in the length direction. The cross-sectional shape of the protrusion 11 in the XZ plane is the above-mentioned isosceles triangle. Therefore, the inclination angle of the first side surface 14 is the same as the inclination angle of the second side surface 15, and each has an angle value θc (see Figure 4B In other words, it can be said that the protrusion 11 is a symmetrical surface protrusion having a first side surface 14 and a second side surface 15 that are symmetrical to each other with the top 12 as the center.

[0035] In contrast, in each of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b, the inclination angle of the side surface inclined toward the inner side of the concavo-convex portion 10b is different from the inclination angle of the side surface inclined toward the outer side of the concavo-convex portion 10b. In the following, the inclination angle of the side surface inclined toward the inner side of the concavo-convex portion 10b is defined as the inner inclination angle. At the same time, the inclination angle of the side surface inclined toward the outer side of the concavo-convex portion 10b is defined as the outer inclination angle. Here, the inner side of the concavo-convex portion 10b is the side on which the center plane CP is set. The outer side of the concavo-convex portion 10b is the side opposite to the side on which the center plane CP is set. In each of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b, the outer inclination angle is smaller than the inner inclination angle. Further, 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 top angle of the protrusion 11.

[0036] Specifically, the first asymmetric surface protrusion 11a has a first side surface 14a inclined toward the outside of the concavo-convex portion 10b, and a second side surface 15a inclined toward the inside of the concavo-convex portion 10b. Figure 3 As shown, it is assumed that at a position where the first asymmetric surface protrusion 11a is provided, an imaginary protrusion 11v having the same shape as each of the plurality of protrusions 11 is provided continuously with the protrusion 11. It is assumed that the position of the top 12 of the first asymmetric surface protrusion 11a is the position of the top 12 of the imaginary protrusion 11v. The angle value θb of the outer inclination angle of the first side surface 14a is smaller than the angle value θa of the inner inclination angle of the second side surface 15a. In addition, the sum of the angle value θa and the angle value θb is the angle value θ. In addition, since the inner inclination angle is set to the angle value θa, the area of ​​the first side surface 14 of the protrusion 11 adjacent to the first asymmetric surface protrusion 11a, which is continuous with the end of the second side surface 15a, becomes smaller than the area of ​​the first side surface 14 of the other protrusions 11.

[0037] Similarly, the second asymmetric surface protrusion 11b has a first side surface 14b inclined toward the inner side of the concavo-convex portion 10b and a second side surface 15b inclined toward the outer side of the concavo-convex portion 10b. Figure 3As shown, it is assumed that at the position where the second asymmetric surface protrusion 11b is set, an imaginary protrusion 11v having the same shape as each of the multiple protrusions 11 is continuously set with the protrusion 11, and the position of the top 12 of the second asymmetric surface protrusion 11b is also assumed to be the position of the top 12 of the imaginary protrusion 11v. The angle value θb of the outer inclination angle of the second side surface 15b is smaller than the angle value θa of the inner inclination angle of the first side surface 14b. In addition, this feature that the sum of the angle value θa and the angle value θb is the angle value θ is also similar to the feature of the first asymmetric surface protrusion 11a. Further, since the inner inclination angle of the first side surface 14b is set to the angle value θa, the area of ​​the second side surface 15 of the protrusion 11 adjacent to the second asymmetric surface protrusion 11b, which is continuous with the end of the first side surface 14b, becomes smaller than the area of ​​the second side surface 15 of the other protrusions 11.

[0038] 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 mutually symmetrical shapes centered on 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 mutually symmetrical shapes centered on the central plane CP.

[0039] Next, the operation of the ultrasonic bonder 1 using the horn 10 will be described.

[0040] Figure 4A 1 is a side view of the ultrasonic bonder 1 showing various states when performing a bonding operation. Figure 4B is with Figure 4A An enlarged view of the vicinity of the second asymmetric surface protrusion 11b corresponding to portion IVB in FIG.

[0041] First, if Figure 1 As shown, as the initial state of the bonding operation, it is assumed that the three previously exposed conductors 121 are inserted between the first end surface 10a of the welding head 10 and the second end surface 20a of the anvil 20. From the initial state, the ultrasonic bonder 1 uses a separate member to limit the width direction of the three conductors 121 along the Y direction. Figure 4A As shown, the ultrasonic bonder 1 bonds the conductors 121 to each other by applying ultrasonic vibration to the conductors using the horn 10 while applying a load P to the conductors using the anvil 20. Figure 4AIn the example shown, it is assumed that three conductors 121 are arranged in the up-down direction. Hereinafter, the conductor 121 disposed at the lowermost portion is referred to as the first conductor 121a, the conductor 121 disposed at the middle portion is referred to as the second conductor 121b, and the conductor 121 disposed at the uppermost portion is referred to as the third conductor 121c. The concavo-convex portion 10b formed on the first end surface 10a contacts the first conductor 121a, and the concavo-convex portion 20b formed on the second end surface 20a contacts the third conductor 121c.

[0042] During the bonding operation, Figure 4A As shown in the attenuation direction Dm in FIG. 1 , the vibration of the welding head 10 propagates between the three conductors 121 while attenuating, and reaches the anvil 20. Therefore, in order to suppress the attenuation of the vibration and transmit the vibration to the conductor 121 more effectively, the welding head 10 has a concave-convex portion 10b, and a part of it extends into the first conductor 121a.

[0043] As a comparative example, it is assumed that the concavo-convex portion 10b of the welding head 10 has an imaginary protrusion 11v having the same shape as the other protrusions 11, instead of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b. Figure 4B In FIG. 1 , as an example, an imaginary protrusion 11v is drawn with a double-dashed line instead of the second asymmetric surface protrusion 11b. Figure 4B , the angle value of the inclination angle of the second side surface 15 of the imaginary protrusion 11v is the same as the angle value θc of the inclination angle of the second side surface 15 of the other protrusions 11. When the welding head 10 vibrates and the imaginary protrusion 11v extends into the first conductor 121a, as shown in FIG. Figure 4B As shown by the double-dashed arrow in FIG. 1 , the reaction force applied to the first conductor 121 a is directed relatively upward toward the outside of the concavo-convex portion 10 b.

[0044] In contrast, in this embodiment, the concave-convex portion 10b of the welding head 10 has a first asymmetric surface protrusion 11a and a second asymmetric surface protrusion 11b. Figure 4B , focusing on the second asymmetric surface protrusion 11b, as described above, the angle value θb of the outer inclination angle of the second side surface 15b is smaller than the angle value θa of the inner inclination angle of 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 top angle of the protrusion 11. That is, the angle value θb of the outer inclination angle of 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 Figure 4BAs shown, when the second asymmetric surface protrusion 11b extends into the first conductor 121a, the reaction force applied to the first conductor 121a is directed to the outside of the concave-convex portion 10b, as shown by the white arrow. However, the reaction force applied by the second asymmetric surface protrusion 11b is directed to a direction closer to the horizontal direction than the imaginary protrusion 11v. Therefore, the vibration direction component of the reaction force when the second asymmetric surface protrusion 11b is present is greater than the vibration direction component when the imaginary protrusion 11v is present. Therefore, the vibration of the welding head 10 is transmitted over a wider range between the three conductors 121.

[0045] In the first asymmetric surface protrusion 11 a , since the outer inclination angle of the first side surface 14 a is set to the angle value θb, the vibration of the horn 10 is transmitted among the three conductors 121 in a wider range.

[0046] On the other hand, if the vertex angles of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b are set too small, it is conceivable that the first conductor 121a in contact with the protrusion may be easily cut, or the respective asymmetric surface protrusions themselves may be easily worn, which is not desirable. Therefore, in the present embodiment, the angle value θb of the outer inclination angle is set to be smaller than the angle value θc, while the angle value θa of the inner inclination angle is set to be larger than the angle value θc. By setting the inclination angles of the respective side surfaces in this way, it is possible to prevent the vertex angles of the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b from being too small.

[0047] Next, the effects of the horn 10 and the ultrasonic bonder 1 using the horn 10 will be described.

[0048] The horn 10 applies ultrasonic vibration to a plurality of objects to be joined as conductors 121 sandwiched between the anvil 20 and the horn 10 to join the plurality of objects to be joined to each other. The horn 10 has a knurled concave-convex portion 10b on a first end face 10a in contact with the object to be joined, and the concave-convex portion 10b is formed by a plurality of protrusions 11 extending in a width direction perpendicular to the vibration direction of the horn 10. Among the plurality of protrusions 11, at least one pair of protrusions symmetrically arranged at the two outermost ends in the direction along the vibration direction is an asymmetric surface protrusion. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the top of the asymmetric surface protrusion as the vertex. Among the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface inclined toward the outside of the concave-convex portion 10b is defined as an outer inclination angle, and the inclination angle of the other side surface inclined toward the inside of the concave-convex portion 10b is defined as an 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.

[0049] Furthermore, the ultrasonic bonder 1 bonds a plurality of objects to be bonded to each other by applying ultrasonic vibration from a horn to the plurality of objects to be bonded sandwiched between the horn and the anvil 20. Here, the horn is the horn 10 described above.

[0050] The vibration direction of the welding head 10 corresponds to the direction along the X direction in the above example. The width direction of the welding head 10 corresponds to the direction along the Y direction in the above example. A pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 11a and the second asymmetric surface protrusion 11b in the above example. In the first asymmetric surface protrusion 11a, the side surface defining the outer inclination angle is defined as the first side surface 14a, and the side surface defining the inner inclination angle is defined as the second side surface 15a. In the second asymmetric surface protrusion 11b, the side surface defining the outer inclination angle is defined as the second side surface 15b, and the side surface defining the inner inclination angle is defined as the first side surface 14b.

[0051] The welding head 10 has a knurled convex-concave portion 10b on the first end surface 10a in contact with the object to be joined. Among the multiple protrusions 11 constituting the concave-convex portion 10b, at least one pair of protrusions symmetrically arranged at the two outermost ends in the direction of the vibration direction are asymmetric surface protrusions, and the asymmetric protrusions are set so that the angle value θa of the inner inclination angle and the angle value θb of the outer inclination angle meet the above conditions. Therefore, according to the welding head 10 having the concave-convex portion 10b with the above-mentioned asymmetric surface protrusions, the vibration direction component of the reaction force applied to the object to be joined can be greater than the vibration direction component of the welding head of the comparative example, the concave-convex portion 10b of the welding head of the comparative example does not have an asymmetric surface protrusion. Therefore, the vibration of the welding head 10 can be transmitted between multiple objects to be joined in a wider range.

[0052] Generally, when the number of objects to be joined is large, it is assumed that the attenuation of the vibration of the horn becomes large, and the joining between the objects to be joined becomes weak. In contrast, according to the ultrasonic joining using the horn 10 according to the present embodiment, the vibration of the horn 10 can be effectively transmitted to the objects to be joined, and this is advantageous even when the number of objects to be joined is large.

[0053] As described above, according to the present embodiment, it is possible to provide the horn 10 and the ultrasonic bonder 1 which are advantageous in suppressing the attenuation of ultrasonic vibrations propagating to a plurality of objects to be bonded.

[0054] Furthermore, in the welding head 10 , the cross-sectional shape perpendicular to the width direction of those protrusions 11 among the plurality of protrusions 11 that are not asymmetric surface protrusions may be an isosceles triangle having the top 12 of the protrusion 11 as a vertex.

[0055] According to the welding head 10, the cross-sectional shape perpendicular to the width direction of the protrusion 11 which is not an asymmetric surface protrusion among the plurality of protrusions 11 is a simple shape. Therefore, the shape can be set according to the shape of the protrusion provided in the conventional welding head.

[0056] Furthermore, in the welding head 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 top angle of the protrusion 11 which is not an asymmetric surface protrusion.

[0057] According to the welding head 10, the angle value θb of the outer inclination angle is set relatively small, while the angle value θa of the inner inclination angle is set relatively large. Therefore, it is possible to suppress the top angle of the asymmetric surface protrusion from being too small. This can prevent the object to be joined that the concave-convex portion 10b contacts from being damaged due to the shape of the asymmetric surface protrusion, or prevent the asymmetric surface protrusion itself from being easily worn.

[0058] Furthermore, the angle value θ set as the vertex angle of the protrusion 11 of the welding head 10 may be in the range of 60 to 160 degrees. More preferably, the angle value θ set as the vertex angle of the protrusion 11 may be 140 degrees.

[0059] As described above, if the angle value θ is too large, there is a risk that the efficiency of the welding head 10 in transmitting vibration to the conductor 121 through each protrusion 11 is deteriorated. Meanwhile, if the angle value θ is too small, there is a risk that each protrusion 11 damages the object to be joined. In contrast, according to the welding head 10, these undesirable problems can be avoided in advance by setting the angle value θ within the above range or at a specific value.

[0060] (Second embodiment)

[0061] Figure 5 1 is a side view of the concavo-convex portion 50 b of the welding head 50 according to the second embodiment, viewed in the Y direction.

[0062] First, similar to the horn 10 according to the first embodiment, the horn 50 applies ultrasonic vibration to a plurality of objects to be joined sandwiched between the horn and the anvil 20 to join the plurality of objects to be joined to each other. Meanwhile, instead of the concavoconvex portion 10b formed in the horn 10, the horn 50 has a knurled concavoconvex portion 50b on the first end face 50a in contact with the object to be joined, and the concavoconvex portion 50b is formed by a plurality of protrusions 51 extending in a width direction perpendicular to the vibration direction of the horn 50. Among the plurality of protrusions 51, at least one pair of protrusions symmetrically arranged at the two outermost ends in the direction along the vibration direction is an asymmetric surface protrusion. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the top of the asymmetric surface protrusion as the vertex. Among the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface inclined toward the outside of the concavoconvex portion 50b is defined as the outer inclination angle, and the inclination angle of the other side surface inclined toward the inner side of the concavoconvex portion 50b 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.

[0063] The vibration direction of the welding head 50 corresponds to the direction along the X direction in the above example. The width direction of the welding head 50 corresponds to the direction along the Y direction in the above example. A pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 51a and the second asymmetric surface protrusion 51b in the above example. In the first asymmetric surface protrusion 51a, the side surface defining the outer inclination angle is the first side surface 54a, and the side surface defining the inner inclination angle is the second side surface 55a. In the second asymmetric surface protrusion 51b, the side surface defining the outer inclination angle is the second side surface 55b, and the side surface defining the inner inclination angle is the first side surface 54b.

[0064] Furthermore, the ultrasonic bonder 1 bonds a plurality of objects to be bonded to each other by applying ultrasonic vibration from the horn to the plurality of objects to be bonded sandwiched between the horn and the anvil 20. Here, the horn is the horn 50 described above.

[0065] That is, the horn 50 and the ultrasonic bonder 1 including the horn 50 can achieve the same effects as those in the first embodiment.

[0066] In addition, the first side surface 54a of the first asymmetric surface protrusion 51a of the welding head 50 facing the outer side of the concavoconvex part 50b can be perpendicular to the first end surface 50a. Similarly, the second side surface 55b of the second asymmetric surface protrusion 51b facing the outer side of the concavoconvex part 50b can be perpendicular to the first end surface 50a.

[0067] According to the welding head 50, since the vertex angle of each of the first asymmetric surface protrusion 51a and the second asymmetric surface protrusion 51b is limited only by the inner inclination angle, the shape of the vertex is sharper than that in the first embodiment. Therefore, the asymmetric surface protrusion is more likely to be stuck on the object to be joined. This is advantageous when it is desired to increase the vibration direction component of the reaction force applied to the object to be joined. For example, the angle value of the inner inclination angle can be the same as the angle value θa of the inner inclination angle in the first embodiment.

[0068] (Third Embodiment)

[0069] Figure 6 1 is a side view of the concavo-convex portion 60 b of the welding head 60 according to the third embodiment, viewed along the Y direction.

[0070] First, similar to the horn 10 according to the first embodiment, the horn 60 applies ultrasonic vibration to a plurality of objects to be joined sandwiched between the horn and the anvil 20 to join the plurality of objects to be joined to each other. Meanwhile, instead of the concavoconvex portion 10b formed in the horn 10, the horn 60 has a knurled concavoconvex portion 60b on the first end face 60a in contact with the object to be joined, and the concavoconvex portion 60b is formed by a plurality of protrusions 61 extending in a width direction perpendicular to the vibration direction of the horn 60. Among the plurality of protrusions 61, at least one pair of protrusions symmetrically arranged at the two outermost ends in the direction along the vibration direction is an asymmetric surface protrusion. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the top of the asymmetric surface protrusion as the vertex. Among the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface inclined to the outside of the concavoconvex portion 60b is defined as the outer side inclination angle, and the inclination angle of the other side surface inclined to the inner side of the concavoconvex portion 60b is defined as the inner side 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.

[0071] The vibration direction of the welding head 60 corresponds to the direction along the X direction in the above example. The width direction of the welding head 60 corresponds to the direction along the Y direction in the above example. A pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 61a and the second asymmetric surface protrusion 61b in the above example. In the first asymmetric surface protrusion 61a, the side surface defining the outer inclination angle is the first side surface 64a, and the side surface defining the inner inclination angle is the second side surface 65a. In the second asymmetric surface protrusion 61b, the side surface defining the outer inclination angle is the second side surface 65b, and the side surface defining the inner inclination angle is the first side surface 64b.

[0072] Furthermore, the ultrasonic bonder 1 bonds a plurality of objects to be bonded to each other by applying ultrasonic vibration from the horn to the plurality of objects to be bonded sandwiched between the horn and the anvil 20. Here, the horn is the above-described horn 60.

[0073] That is, the horn 60 and the ultrasonic bonder 1 including the horn 60 achieve the same effects as those in the first embodiment.

[0074] Furthermore, in the welding head 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 top angle of the protrusion 61 which is not an asymmetric surface protrusion.

[0075] The apex angle of the asymmetric surface protrusion of the welding head 60 is set larger than the apex angle of the welding head 10 of the first embodiment. Therefore, for example, when priority is given to avoiding damage to the objects to be joined that come into contact with the asymmetric surface protrusion or wear of the asymmetric surface protrusion itself, this is advantageous.

[0076] (Fourth embodiment)

[0077] Figure 7 1 is a side view of the concavo-convex portion 70 b of the welding head 70 according to the fourth embodiment, viewed along the Y direction.

[0078] Similar to the horn 10 according to the first embodiment, the horn 70 applies ultrasonic vibration to a plurality of objects to be joined sandwiched between the horn and the anvil 20 to join the plurality of objects to be joined to each other. Meanwhile, instead of the concavo-convex portion 10b formed in the horn 10, the horn 70 has a knurled concavo-convex portion 70b on the first end face 70a in contact with the object to be joined, and the concavo-convex portion 70b is formed by a plurality of protrusions extending in a width direction perpendicular to the vibration direction of the horn 70. Among the plurality of protrusions, at least one pair of protrusions symmetrically arranged at the two outermost ends in the direction along the vibration direction is an asymmetric surface protrusion. The cross-sectional shape of the asymmetric surface protrusion perpendicular to the width direction is a triangle with the top of the asymmetric surface protrusion as the vertex. Among the two side surfaces of the asymmetric surface protrusion, the inclination angle of one side surface inclined to the outside of the concavo-convex portion 70b is defined as the outer inclination angle, and the inclination angle of the other side surface inclined to the inside of the concavo-convex portion 70b 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.

[0079] The vibration direction of the welding head 70 corresponds to the direction along the X direction in the above example. The width direction of the welding head 70 corresponds to the direction along the Y direction in the above example. A pair of asymmetric surface protrusions corresponds to the first asymmetric surface protrusion 71a and the second asymmetric surface protrusion 71b in the above example. In the first asymmetric surface protrusion 71a, the side surface defining the outer inclination angle is the first side surface 74a, and the side surface defining the inner inclination angle is the second side surface 75a. In the second asymmetric surface protrusion 71b, the side surface defining the outer inclination angle is the second side surface 75b, and the side surface defining the inner inclination angle is the first side surface 74b.

[0080] Furthermore, the ultrasonic bonder 1 bonds a plurality of objects to be bonded to each other by applying ultrasonic vibration from the horn to the plurality of objects to be bonded sandwiched between the horn and the anvil 20. Here, the horn is the above-described horn 70.

[0081] That is, the horn 70 and the ultrasonic bonder 1 including the horn 70 achieve the same effects as those in the first embodiment.

[0082] According to the definition of the welding head 70, among the plurality of protrusions, it is sufficient that at least one pair of protrusions symmetrically arranged at the two outermost ends in the direction along the vibration direction are asymmetric surface protrusions. Figure 7 As shown, the plurality of protrusions may be asymmetric surface protrusions. In this case, with the center plane CP as the center, all the protrusions 11 on one side in the length direction are first asymmetric surface protrusions 71a, and all the protrusions 11 on the other side in the length direction are second asymmetric surface protrusions 71b. Each first asymmetric surface protrusion 71a and each second asymmetric surface protrusion 71b have mutually symmetrical shapes with the center plane CP as the center.

[0083] The welding head 70 has more asymmetric surface protrusions than the welding head 10 of the first embodiment, wherein the angle value θb of the outer inclination angle is set relatively small. Therefore, for example, this is advantageous when it is desired to transmit the vibration of the welding head 70 in a wider range between a plurality of objects to be joined.

[0084] In each of the above-described embodiments, a case has been exemplified in which all of the plurality of objects to be joined are the conductors 121 as the core wires of the electric wires 120. However, at least one of the plurality of objects to be joined may be a plate such as a metal plate.

[0085] Although specific embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. Indeed, the novel embodiments described herein may be implemented in a variety of other forms; furthermore, various omissions, substitutions, and changes in the form of the embodiments described herein may be made without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover such forms or modifications as fall within the scope and spirit of the invention.

Claims

1. A welding head, which applies ultrasonic vibration to a plurality of objects to be joined sandwiched between an anvil and the welding head, so as to join the objects to be joined to each other, the welding head comprising: A knurled concavoconvex portion, the concavoconvex portion being formed by a plurality of protrusions, each of the protrusions extending in a width direction perpendicular to the vibration direction of the welding head, and the concavoconvex portion being formed on an end face in contact with one of the objects to be joined, wherein Among the plurality of protrusions, at least a pair of protrusions symmetrically arranged at two outermost ends in the direction along the vibration direction are asymmetric surface protrusions, The cross-sectional shape of each asymmetric surface protrusion perpendicular to the width direction is a triangle with the top of each asymmetric surface protrusion as the vertex, Among the two side surfaces of each of the asymmetric surface protrusions, an inclination angle of one of the two side surfaces inclined toward the outer side of the concavo-convex portion is defined as an outer inclination angle, and an inclination angle of the other of the two side surfaces inclined toward the inner side of the concavo-convex portion is defined as an inner inclination angle, and The angle value of the outer inclination angle is smaller than the angle value of the inner inclination angle.

2. The welding head according to claim 1, wherein: A cross-sectional shape perpendicular to the width direction of a protrusion among the plurality of protrusions that is not the asymmetric surface protrusion is an isosceles triangle with the top of the protrusion as a vertex.

3. The welding head according to claim 2, wherein: The sum of the angle value of the outer inclination angle and the angle value of the inner inclination angle is the same as the angle value of the top angle of the protrusion that is not the asymmetric surface protrusion.

4. The welding head according to claim 2, wherein: The sum of the angle value of the outer inclination angle and the angle value of the inner inclination angle is greater than the angle value of the top angle of the protrusion that is not the asymmetric surface protrusion.

5. The welding head according to claim 3 or 4, wherein: The angle value set as the vertex angle of the protrusion ranges from 60 degrees to 160 degrees.

6. The welding head according to claim 5, wherein: The angle value set as the vertex angle of the protrusion is 140 degrees.

7. The welding head according to claim 1 or 2, wherein: One of the side surfaces of each of the asymmetric surface protrusions that faces the outside of the concavo-convex portion is perpendicular to the end surface.

8. An ultrasonic bonder that applies ultrasonic vibration from a horn to a plurality of objects to be bonded sandwiched between the horn and an anvil to bond the plurality of objects to be bonded to each other, wherein: The welding head is the welding head according to any one of claims 1 to 7.

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