Amplitude-change pole welding nozzle and ultrasonic jointing device

Abstract

The invention provides an amplitude-change pole welding tip which can be simply and reliably installed on an ultrasonic jointing device and is stable in jointing action. The horn tip (6) is provided with: a bottom plate part (6a) provided with a plurality of through holes (61, 62) for attaching to the ultrasonic LT horn (4); and a joint part (6b) protruding in the vertical direction from the bottom plate part (6a). The ratio (h / w) of the length (h) of the joining section (6b) from the upper surface side of the bottom plate section (6a) to the thickness (w) of the joining section (6b) is 1.5 or less.

Description

[Technical field]

[0001] The present invention relates to a horn welding nozzle for ultrasonic joining and an ultrasonic joining device which is equipped with and uses the horn welding nozzle. [Background Technology]

[0002] Conventionally, in ultrasonic joining devices, various types of horn tips having different outer shapes or shapes of joining surfaces are prepared, and an optimum horn tip can be selected according to workpieces to be joined or joining conditions.

[0003] For example, in the ultrasonic bonding device of Patent Document 1, for a welding nozzle having a relatively large width, the welding nozzle component is freely removable relative to the ultrasonic horn. When the welding nozzle component is mounted on the horn, the tapered portion and the guide portion of the welding nozzle component are inserted into the first hole portion and the second hole portion of the welding nozzle component mounting hole from the lower side of the horn, and the screw component is inserted into the third hole portion of the welding nozzle component mounting hole from the upper side of the horn, and the screw component is tightened from the upper side of the horn (see Patent Document 1).

[0004] [Prior art literature]

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-16741 [Summary of the invention]

[0007] Problems to be solved by the invention

[0008] However, in order to reliably fix the welding nozzle component, the device of Patent Document 1 needs to form first to third holes on the ultrasonic horn, which takes time and cost to process. In addition, depending on the shape of the welding nozzle component, the screw may be loosened during the connection and the nozzle may slide relative to the mounting portion, so a structure that can be reliably mounted is sought.

[0009] In addition, the length from the root to the front end of the welding nozzle component is related to the natural vibration frequency of the welding nozzle component. According to the natural vibration frequency of the welding nozzle component, the welding nozzle component and the ultrasonic horn are displaced in opposite directions to each other, so there is a problem that the bottom surface of the welding nozzle component floats from the mounting portion during bonding, which affects the bonding accuracy.

[0010] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a horn welding tip that can be easily and reliably attached to an ultrasonic joining device and that can perform stable joining.

[0011] Means for solving problems

[0012] In order to achieve the above-mentioned purpose, the first invention is a variable amplitude welding nozzle, which is used to join workpieces by ultrasonic joining, and is characterized in that it comprises: a bottom plate portion, which is provided with a plurality of through holes for screws to pass through; and a joining portion, which protrudes in a vertical direction from the bottom plate portion, and the ratio h / w of the length h of the joining portion from the upper surface side of the bottom plate portion to the thickness w of the joining portion is less than 1.5.

[0013] The horn welding tip of the present invention is mounted on the ultrasonic horn by screws using the plurality of through holes of the bottom plate, so that it can be reliably fixed. The joining portion protruding in the vertical direction from the bottom plate is used for joining the workpieces.

[0014] In addition, the ratio h / w of the length h of the joint portion of the horn welding tip from the upper surface side of the bottom plate portion to the thickness w of the joint portion may be 1.5 or less. When the thickness w and the length h of the joint portion are set to this ratio, the natural vibration frequency of the horn welding tip can be made different from the natural vibration frequency of the ultrasonic horn, so that the resonance of the welding tip component and the ultrasonic horn can be avoided when joining the workpieces. Therefore, the workpieces can be joined stably.

[0015] Preferably, in the horn welding tip of the first invention, the engaging portion protrudes in a vertical direction from one end edge of the bottom plate portion extending in the longitudinal direction.

[0016] According to this structure, the horn welding tip (substantially L-shaped) in which the joint portion protrudes vertically from the end edge of the bottom plate portion is easier to process, and the bottom plate portion can be made larger than the joint portion, thereby increasing the number of through holes and the degree of freedom in the arrangement of the through holes.

[0017] In addition, preferably, the horn welding tip of the first invention includes a thick wall portion whose thickness gradually increases from the bottom plate portion toward a base end portion continuous with the joining portion.

[0018] By providing the thick wall portion at the portion formed by the bottom plate portion of the horn welding tip and the joint portion, the joint portion does not wobble when the workpieces are joined, and the workpieces can be joined stably.

[0019] In addition, in the horn welding tip of the first invention, preferably, a groove is provided on the lower surface side of the bottom plate portion that contacts the surface of the ultrasonic horn.

[0020] When the contact area between the horn welding tip and the ultrasonic horn is large, the force generated by the tightening screw is dispersed, and the contact surfaces rub against each other due to ultrasonic vibration. Therefore, the friction heat caused by ultrasonic vibration increases, but by providing a groove on the lower surface side of the horn welding tip, the generation of friction heat can be suppressed.

[0021] The ultrasonic joining device of the second invention is characterized in that it comprises: a transformer nozzle, which comprises a bottom plate portion provided with a plurality of through holes for screws to pass through and a joining portion protruding in a vertical direction from the bottom plate portion, wherein the length of the joining portion from the upper surface side of the bottom plate portion is less than half of the resonant length; and an ultrasonic transformer, which is capable of installing the transformer nozzle, and a threaded hole corresponding to the through hole of the transformer nozzle is provided on at least one side surface of the front end portion of the ultrasonic transformer.

[0022] The ultrasonic bonding device of the present invention has a front end portion corresponding to the horn welding nozzle of the first invention. The front end portion has screw holes corresponding to the through holes of the horn welding nozzle at the same interval, so that it can be used in combination.

[0023] Preferably, in the ultrasonic bonding device according to the second aspect of the present invention, the front end portion has a quadrangular prism shape.

[0024] According to this configuration, the horn tip is attached to the side surface of the quadrangular prism by means of screws, so that both can be securely fixed.

[0025] In the ultrasonic bonding device of the second invention, preferably, the bonding portion protrudes vertically from one end edge of the bottom plate portion extending in the longitudinal direction, and the end surface of the front end portion is flush with the end surface of the bonding portion of the horn welding nozzle.

[0026] In the present invention, the horn welding tip is mounted so that the end surface of the front end of the ultrasonic horn is flush with the end of the joint portion of the substantially L-shaped columnar horn welding tip. This makes it easy to position the horn welding tip and the workpiece during joining.

[0027] In addition, in the ultrasonic bonding device according to the second aspect of the present invention, preferably, the screw hole is provided at a position where stress is lower than a central portion in the axial direction of the front end portion.

[0028] This stress is a force generated by the ultrasonic horn expansion and contraction caused by ultrasonic vibration. The stress in the center of the ultrasonic horn is higher and the expansion and contraction is larger. That is, the deformation of the threaded hole also increases. In this regard, the expansion and contraction and deformation caused by ultrasonic vibration of the threaded hole set at a position where the stress is lower than that of the center are smaller. Therefore, the screws fixing the horn welding nozzle will not loosen, and the horn welding nozzle can be reliably fixed.

[0029] In the ultrasonic bonding device according to the second aspect of the present invention, preferably, a convex portion for preventing the horn tip from shifting relative to the front end portion is provided on the surface of the front end portion to which the horn tip is attached.

[0030] According to this configuration, the horn tip can be prevented from being displaced by the convex portion provided on the front end portion of the ultrasonic horn, so that it is possible to prevent the horn tip from being displaced when welding the workpieces and thereby preventing the welding accuracy from being reduced.

[0031] In addition, in the ultrasonic bonding device according to the second aspect of the present invention, preferably, the screw hole provided at a position not interfering with the horn welding tip is capable of attaching and detaching a vibration adjusting member.

[0032] The vibration adjustment component can be installed in the threaded hole provided on the ultrasonic horn at a position that does not interfere with the horn welding nozzle. By using the vibration adjustment component to adjust the vibration amplitudes at both ends of the ultrasonic horn and make them equal, the joining accuracy of the workpieces can be improved. [Drawings]

[0033] Figure 1 It is a diagram for explaining the overall structure of an ultrasonic bonding device according to an embodiment of the present invention.

[0034] Figure 2 This is a three-dimensional diagram of the ultrasonic LT horn.

[0035] Figure 3A This is a perspective view of the horn welding nozzle (top surface side).

[0036] Figure 3B This is a perspective view of the horn welding nozzle (bottom surface side).

[0037] Figure 4 It is a three-dimensional picture of the horn welding nozzle (with cutouts).

[0038] Figure 5 This is a perspective view of the horn welding nozzle (with thick wall).

[0039] Fig. 6A This is a three-dimensional view of a horn welding nozzle (T-shaped).

[0040] Figure 6B This is a side view of the horn tip (T-shaped) when it is attached to the ultrasonic LT horn.

[0041] Fig. 7A This is a perspective view (top side) of a horn welding nozzle (three through holes).

[0042] Figure 7B This is a perspective view (bottom surface side) of the horn welding nozzle (three through holes).

[0043] Fig. 8A This is a three-dimensional view of the horn welding nozzle (deformed T-shape).

[0044] Figure 8BThis is a side view of the horn tip (deformed T-shaped) when it is attached to the ultrasonic LT horn.

[0045] Fig. 9 It is a three-dimensional view of the horn welding nozzle (with ribs and protrusions).

[0046] Fig.10 This is a side view of the horn nozzle when it is attached to the ultrasonic LT horn.

[0047] Fig.11 It is a diagram for explaining the length of the joint portion of the horn welding tip.

[0048] Fig.12 (a) is a diagram showing a variable-horn welding tip of length L (resonance length), (b) is a diagram showing a variable-horn welding tip of length L / 2 to L, (c) is a diagram showing a variable-horn welding tip of length L / 2, and (d) is a diagram showing a variable-horn welding tip of length L / 3.

[0049] Fig.13 It is a diagram for explaining the installation position of the horn welding tip in the axial direction of the ultrasonic LT horn.

[0050] Fig.14A This is a side view of a state where a horn tip is attached to an ultrasonic LT horn (front end portion: embodiment).

[0051] Fig. 14B Yes Description Fig.14A A detailed diagram of the front end of the Ultrasonic LT horn.

[0052] Fig.15A This is a side view of the horn tip when it is attached to the ultrasonic LT horn (tip end: modified form).

[0053] Fig. 15B Yes Description Fig.15A A detailed diagram of the front end of the Ultrasonic LT horn.

[0054] Fig.16 This is a diagram for explaining an ultrasonic bonding device in which a balancer is attached to the front end portion of an ultrasonic LT horn. [Specific implementation method]

[0055] Hereinafter, embodiments of the ultrasonic bonding device of the present invention will be described with reference to the drawings.

[0056] First, refer to Figure 1The overall structure of an ultrasonic bonding device 1 according to an embodiment of the present invention is described. The ultrasonic bonding device 1 is a device for welding a bonding object (workpiece) such as a metal plate by using ultrasonic composite vibration described later. The ultrasonic bonding device 1 is mainly used for bonding electrodes of lithium-ion batteries or semiconductor elements, and the same or different metals.

[0057] The ultrasonic bonding device 1 is composed of an ultrasonic vibrator (Langevin Type) 2, an ultrasonic amplifier horn 3, an ultrasonic LT horn 4, a horn welding nozzle 6, and an anvil 7. In addition, an oscillating device 8, a pressurizing device 10, a sensor 12, a control device 13, and a display device 14 are also part of the ultrasonic bonding device 1.

[0058] When a power supply voltage is applied to the oscillation device 8 from a power supply (not shown), the voltage signal is transmitted to the + electrode and the - electrode of the ultrasonic vibrator 2, and the ultrasonic vibrator 2 vibrates, generating ultrasonic vibration (about 20KHz). The ultrasonic vibration generated by the ultrasonic vibrator 2 is transmitted to the cylindrical ultrasonic amplifying horn 3 installed on one end of the ultrasonic vibrator 2, and the vibration amplitude is amplified. Furthermore, the ultrasonic vibration is transmitted to the cylindrical ultrasonic LT horn 4 installed on one end of the ultrasonic amplifying horn 3 (not the end on one side of the ultrasonic vibrator 2).

[0059] The ultrasonic vibration generated by the ultrasonic vibrator 2 is transmitted along the long axis direction of the ultrasonic amplifying horn 3 and the ultrasonic LT horn 4 (longitudinal vibration of the ultrasonic wave), but a vibration component converted from the longitudinal vibration to the transverse vibration is generated through the multiple inclined slits S of the ultrasonic LT horn 4. Then, the ultrasonic vibration (complex vibration) is transmitted to the horn welding nozzle 6 screwed on one end of the ultrasonic LT horn 4 (not the end on one side of the ultrasonic amplifying horn 3).

[0060] The horn welding nozzle 6 has a front end portion that contacts one of the multiple workpieces W located at the uppermost side when joining multiple workpieces W (for example, multiple flat plate-shaped workpieces overlapped in the thickness direction). At this time, the control device 13 adjusts the phase and amplitude of the longitudinal vibration and the torsional vibration of the ultrasonic vibration, thereby generating a composite vibration (for example, elliptical vibration) at one end of the ultrasonic LT horn 4, and the front end portion of the horn welding nozzle 6 vibrates to draw an elliptical orbit on the surface of the upper workpiece W.

[0061] This vibration removes impurities on the surface of the workpiece W, thereby promoting plastic deformation of the surface of the workpiece W. In addition, the horn welding nozzle 6 can be replaced according to the type of workpiece W. Figure 1 The horn welding tip shown is substantially L-shaped plate-shaped or L-shaped column-shaped and has a substantially rectangular joint surface that contacts the workpiece W.

[0062] The composite vibration is supplemented by a composite vibration of a first direction perpendicular to the pressing direction and a second direction perpendicular to the first direction when the front end of the horn welding nozzle 6 presses the upper workpiece W. If the phase difference between the first direction vibration component and the second direction vibration component is 90 degrees and the amplitude ratio is 1:1, it becomes a circular vibration, and if the phase difference is 90 degrees and the amplitude ratio is N:1 (N>1, for example, N=2), it becomes an elliptical vibration.

[0063] Furthermore, a high-rigidity pressurizing block (not shown) contacts the flange portion 3a of the ultrasonic amplifying horn 3. Therefore, the pressurizing device 10 can be controlled by the control device 13 to move the ultrasonic bonding device 1 in the vertical direction via the pressurizing block that moves upward and downward.

[0064] In addition, by placing the workpiece W on the anvil 7 as a pedestal, the joining portion 6b of the horn welding tip 6 contacts the workpiece W on the upper portion and applies a static pressure (200 to 800 [N / m 2 ]).

[0065] Generally, when the static pressure is increased, the joining strength is improved, but when the static pressure is excessively increased, the workpiece W is damaged, which causes breakage and cracks. On the other hand, when the static pressure at the beginning of joining is low, the horn welding tip 6 cannot grasp the upper workpiece W, and the upper workpiece W slips and cannot be joined smoothly.

[0066] As methods for generating static pressure, there are a method of lifting the anvil 7 from below and thereby lifting the lower workpiece W by using a cylinder, spring, etc., and a method of pressing down the upper workpiece W from above by controlling the position and (or) displacement speed of the variable amplitude welding nozzle 6 by a servo motor. The latter is adopted in this embodiment.

[0067] In addition, a sensor (stroke sensor) 12 is provided to detect the displacement of the pressurizing block, and the control device 13 obtains the amount of pressure (sinking amount) of the horn welding nozzle 6 on the workpiece W. The sensor 12 sends the coordinate change of the horn welding nozzle 6 in the vertical direction during joining to the control device 13, and the control device 13 feedback controls the amount of pressure of the horn welding nozzle 6 on the workpiece W based on the coordinate change, thereby keeping the pressure constant. Therefore, in the pressurizing device 10, it is preferable to use an actuator with a fast response speed to the feedback control signal sent from the control device 13.

[0068] The target value of the amount of penetration of the horn welding tip 6 into the workpiece W or the time variation pattern can be preset by the operator of the ultrasonic bonding device 1 from the display device 14. In this way, when bonding the workpieces, by applying composite vibration while adjusting the amount of penetration and / or static pressure, bonding (solid phase bonding) can be reliably promoted.

[0069] To supplement solid phase bonding, for example, the surface of metal atoms is covered with grease and / or oxide film, which hinders the approach of atoms to each other. In ultrasonic bonding, ultrasonic vibration is applied to the metal to generate strong friction on the metal surface. As a result, the oxide film on the metal surface is removed, and clean and activated metal atoms appear on the bonding surface.

[0070] In this state, by further applying ultrasonic vibration to the metal surface, the movement of atoms becomes active due to the temperature rise caused by frictional heat, generating mutual attraction between atoms, and creating a solid phase bonding state.

[0071] Next, refer to Figure 2 The ultrasonic LT horn 4 of the present embodiment will be described in detail.

[0072] Figure 2 The ultrasonic LT horn 4 shown is composed of a cylindrical portion 4a including an inclined slit S and a quadrangular prism-shaped front end portion 4b. The front end portion 4b is a horizontally long rectangle when viewed from the front side, but may be formed in a square or octagonal shape.

[0073] Two screw holes 41 and 42 for mounting the horn welding tip 6 are provided on the horizontally long surface (mounting surface M) of the front end portion 4b of the ultrasonic LT horn 4. The two screw holes 41 and 42 are arranged in a horizontal direction and are separated from each other. When processing is performed using the ultrasonic bonding device 1, the mounting surface M faces vertically downward (toward the anvil 7) (see FIG. Figure 1 ).

[0074] The screw holes 41 and 42 of the front end portion 4b are internal screw grooves and are provided corresponding to the through holes 61 and 62 of the horn welding tip 6 described later. By providing a plurality of screw holes 41 and 42 to fix the horn welding tip 6, it is possible to prevent the horn welding tip 6 from rotating relative to the front end portion 4b when joining the workpiece W abutting against the horn welding tip 6. In addition, a circular hole 4c is provided on the front end portion 4b of the ultrasonic LT horn 4, but this is not a necessary structure.

[0075] The mounting surface M is preferably sandblasted so that the horn welding tip 6 does not slide relative to the front end 4b. Alternatively, three or more threaded holes arranged in a horizontal direction and separated from each other may be provided on the mounting surface M of the front end 4b of the ultrasonic LT horn 4. In addition, a convex portion 4d (see FIG. 4 ) may be provided to prevent the horn welding tip 6 from shifting relative to the front end 4b. Fig.10 ).

[0076] Next, refer to Figure 3A , Figure 3B The horn tip 6 used in the ultrasonic joining device 1 will be described.

[0077] like Figure 3A As shown, the horn welding nozzle 6 having a roughly L-shaped plate or a roughly L-shaped columnar shape is composed of the following parts: a roughly rectangular plate-shaped bottom plate portion 6a, which is provided with two through holes 61 and 62 arranged separately from each other in the long side direction for mounting to the ultrasonic LT horn 4; and a roughly rectangular plate-shaped joint portion 6b, which protrudes in the vertical direction from one long edge portion of the bottom plate portion 6a.

[0078] That is, the horn welding tip 6 is formed into a substantially L-shaped plate or a substantially L-shaped column shape whose cross-section perpendicular to the long side direction is substantially L-shaped. The L-shaped columnar horn welding tip 6 is relatively easy to process, and the larger flat plate of the two flat plates constituting it is used as the bottom plate portion 6a. That is, the area of ​​the bottom plate portion 6a can be increased, so the number of through holes 61, 62 of the horn welding tip 6 and the degree of freedom of their arrangement can be increased.

[0079] The through holes 61 and 62 are holes without thread grooves, but correspond to the intervals between the thread holes 41 and 42 of the ultrasonic LT horn 4 (front end portion 4b), and the diameter of the holes is one circle larger than the thread holes 41 and 42. The rectangular plane of the joint portion 6b is the contact surface with the upper workpiece W. The shape of the contact surface may be an ellipse or the like, and a plurality of protrusions or recesses may be provided on the contact surface.

[0080] Figure 3B The figure shows the lower surface side (the side in contact with the ultrasonic LT horn 4) of the bottom plate portion 6a of the horn welding tip 6. The lower surface side of the bottom plate portion 6a is a polished flat surface, and a groove portion 63 extending along the entire length of the short side direction is provided in the center portion in the long side direction so as not to contact the surface of the ultrasonic LT horn 4.

[0081] When the contact area between the ultrasonic LT horn 4 and the bottom plate 6a is large, the force generated by the tightening screw is dispersed, and the contact surfaces rub against each other due to the ultrasonic vibration, so the friction heat caused by the ultrasonic vibration becomes large. Therefore, by reducing the contact area between the ultrasonic LT horn 4 and the bottom plate 6a by the groove 63, the force generated by the tightening screw is concentrated, thereby suppressing the generation of friction heat. The groove 63 can also be formed to extend along the long side direction of the lower surface side of the bottom plate 6a, and can also be composed of a combination of continuous or independent grooves extending in the short side direction and the long side direction respectively.

[0082] Alternatively, the flat surface of the bottom plate portion 6a other than the groove portion 63 may be subjected to sandblasting to suppress sliding of the bottom plate portion 6a and the workpiece W when the workpiece W is joined. In addition, if the flat surface is subjected to nitride film treatment, adhesion to the ultrasonic LT horn 4 or rust can be prevented. Furthermore, by rounding or chamfering the edge of the flat surface, the ultrasonic LT horn 4 and / or the horn welding tip 6 (bottom plate portion 6a) can be prevented from being cut.

[0083] It can also be, Figure 4 As shown in the horn welding nozzle 16, it becomes a contact surface of a smaller rectangular plane formed by cutting off the two ends of the joint 16b. Figure 5 The thick wall portion 17c is provided as in the horn welding tip 17 shown in the figure. The thick wall portion 17c is formed by gradually increasing the thickness of the bottom plate portion 17a from the middle portion in the short side direction of the bottom plate portion 17a toward the base end portion continuous with the joint portion 17b in an exponential function or quadratic function with a positive power.

[0084] exist Figure 5 In the embodiment, the through holes 171 and 172 arranged in the long-side direction of the bottom plate 17a are formed to pass through the thickness direction of the bottom plate 17a in a manner avoiding the thick-walled portion 17c. The thick-walled portion 17c of the horn welding tip 17 is also a portion where the bottom plate 17a gradually becomes thicker in an exponential function or quadratic function manner from the middle portion in the short-side direction of the joint portion 17b toward the base end portion continuous with the bottom plate 17a.

[0085] The thick wall portion 17c can suppress the shaking of the joint portion 17b relative to the bottom plate portion 17a when joining the workpiece W, and can stably maintain the joint portion 17b relative to the workpiece W to join the workpiece W. In addition, similar to the horn welding tip 6, a groove portion 173 extending in the short side direction is provided on the lower surface side.

[0086] Thick wall parts are not limited to Figure 5 The thick wall portion may be formed so that the thickness of the bottom plate portion 17a gradually increases from the middle portion in the short side direction of the bottom plate portion 17a toward the base end portion continuous with the joint portion 17b in a linear function or a negative exponential function.

[0087] The through holes 171 and 172 may be formed to penetrate at least partially through the thick portion 17c of the bottom plate 17a in the thickness direction. In addition, the thick portion 17c may be formed so that the bottom plate 17a gradually becomes thicker from the front end of the bottom plate 17a toward the front end of the joint 17b.

[0088] The shape of the horn welding nozzle is not limited to the L-shape. Fig. 6AThe horn welding nozzle 18 having a substantially T-shaped plate or column shape is used in the ultrasonic joining device 1. The horn welding nozzle 18 has a joining portion 18b protruding vertically from the substantially center of the short side direction of the bottom plate portion 18a, and through holes 181 to 184 are provided on both sides of the joining portion 18b.

[0089] Figure 6B This is a side view of the horn welding tip 18 when it is mounted on the ultrasonic LT horn 4. As shown in FIG6 , the horn welding tip 18 is fixed to the ultrasonic LT horn 4 by screws 30 on both sides of the joint 18b. Therefore, when the workpiece W is joined, the horn welding tip 18 can be prevented from shaking relative to the ultrasonic LT horn 4, and the horn welding tip 18 can be stably maintained in contact with the workpiece W to join the workpiece W.

[0090] In addition, various shapes of horn welding nozzles are also considered. Fig. 7A The horn welding nozzle 19 shown is composed of the following parts: a bottom plate portion 19a in a roughly rectangular plate shape, which is provided with three through holes 191, 192, and 193 arranged separately from each other in the horizontal direction or the long side direction; and a connecting portion 19b, which extends along the entire long edge portion of the bottom plate portion 19a and protrudes in the vertical direction relative to the bottom plate portion 19a.

[0091] The horn welding tip 19 can be mounted on an ultrasonic LT horn having a front end portion provided with three threaded holes. According to this method, the horn welding tip 19 can be firmly fixed to the ultrasonic LT horn 4, so that a gap is not easily formed between the horn welding tip 19 and the ultrasonic LT horn (front end portion), and the fixation to the ultrasonic LT horn 4 is more stable than that of a horn welding tip having two through holes.

[0092] like Fig. 7A As shown, the horn welding tip 19 includes a thick wall portion 19c, which makes the bottom plate portion 19a gradually thicker in an exponential or quadratic manner from the middle portion of the bottom plate portion 19a in the short side direction toward the base end portion continuous with the joint portion 19b. Therefore, when joining the workpiece W, the horn welding tip 19 can be prevented from shaking relative to the ultrasonic LT horn 4, and the horn welding tip 19 can be stably maintained in contact with the workpiece W to join the workpiece W.

[0093] Figure 7B The bottom surface side of the bottom plate 19a (the side in contact with the ultrasonic LT horn) is shown. The bottom surface side of the bottom plate 19a is a polished flat surface, but a groove 194 extending along the entire length of the long side direction is provided in the center portion in the short side direction so as not to contact the surface of the ultrasonic LT horn. By reducing the contact area by the portion of the groove 194, the generation of frictional heat between the ultrasonic LT horn 4 and the horn welding tip 19 can be suppressed.

[0094] The force generated by the tightening screw is concentrated on the flat surface extending in the long side direction, so the effect of preventing sliding between the surfaces is improved. In order to prevent the lower surface side of the bottom plate portion 19a and the surface of the ultrasonic LT horn (front end portion) from joining each other, the flat surface may be subjected to nitride film treatment. In addition, a part of the flat surface may be cut to the same height as the groove portion 194 to further reduce the contact area.

[0095] Fig. 8A The illustrated horn welding tip 20 (deformed T-shaped) is composed of the following parts: a substantially rectangular bottom plate portion 20a, which is provided with three through holes 201, 202, and 203 arranged in a horizontal direction and separated from each other; and a joint portion 20b, which extends along the entire length of the long side direction at the center portion in the short side direction of the bottom plate portion 20a and protrudes in the vertical direction relative to the bottom plate portion 20a. A thick wall portion 20c is provided above the joint portion 20b relative to the bottom plate portion 20a, and the thick wall portion 20c gradually increases the wall thickness of the bottom plate portion 20a in an exponential function or quadratic function manner from the middle portion in the short side direction of the bottom plate portion 20a toward the base end portion continuous with the joint portion 20b.

[0096] In addition, three through holes 204, 205, and 206 are provided below the joint portion 20b relative to the bottom plate portion 20a. Figure 8B As shown, the horn welding tip 20 is placed on the end of the ultrasonic LT horn 4 (front end), and is fixed to the ultrasonic LT horn 4 by screws 30 using through holes 201 to 206. By fixing the horn welding tip 20 from two directions, sliding between the lower surface side of the bottom plate 20a and the contact surface of the ultrasonic LT horn 4 can be reliably prevented.

[0097] Fig. 9 The horn welding nozzle 21 shown is composed of the following parts: a bottom plate 21a, which is provided with two through holes 211 and 212 arranged in a horizontal direction and separated from each other; and a joint 21b, which extends along the entire length of the long side direction at the center of the short side direction of the bottom plate 21a and is placed at the end of the bottom plate 21a. The bottom plate 21a has ribs 21c rising toward the joint 21b at both ends in the short side direction.

[0098] The rib 21c is a thick wall portion whose thickness gradually increases in a linear function from the edge in the long side direction of the bottom plate portion 21a toward the base end portion continuous with the joint portion 21b. By providing the rib 21c, in the resonance state of the vibration of the ultrasonic LT horn 4 and the horn welding tip 9, it is possible to prevent the two ends of the bottom plate portion 21a from vibrating in opposite phases and the corner portions of the two ends from vibrating greatly, thereby reducing the joining accuracy of the workpiece W.

[0099] In addition, the joint portion 21b is provided with a plurality of protrusions P. The protrusions P are arranged at equal intervals on the joint portion 21b and are a structure for pressing the workpiece W from above to reliably join the workpiece W. The protrusions P may also be provided on the horn welding tips 6, 16 to 20 described above.

[0100] Fig.10 It is a side view when the horn tip 6 is attached to the ultrasonic LT horn 4 .

[0101] The horn welding tip 6 is preferably installed in such a manner that the front end surface of the joint portion 6b is flush with the front end surface of the front end portion 4b of the ultrasonic LT horn 4. As a result, the position of the horn welding tip 6 and the workpiece W can be easily adjusted when joining the workpiece W. In addition, the installation position of the horn welding tip 6 may also be the rear end side of the axial direction of the ultrasonic LT horn 4, and the details will be described later.

[0102] Generally, when the ultrasonic joining device 1 joins the workpieces W, it is necessary to improve the efficiency of the vibration amplitude of the ultrasonic vibration. Therefore, the natural vibration frequency (resonance frequency) of the horn tip 6 is adjusted to be substantially the same as the natural vibration frequency of the ultrasonic LT horn 4 .

[0103] However, in the L-shaped horn welding tip 6, when the natural vibration frequency of the horn welding tip 6 is made to coincide with the natural vibration frequency of the ultrasonic LT horn 4, the following phenomenon (phase reversal phenomenon) is known: when the front end portion 4b of the ultrasonic LT horn 4 is displaced to the right due to vibration, the horn welding tip 6 (joining portion 6b) is displaced in the opposite direction. As a result, a gap is generated between the ultrasonic LT horn 4 and the horn welding tip 6, the vibration of the joint portion 6b of the horn welding tip 6 becomes unstable, and the joining accuracy of the workpiece W is reduced.

[0104] As a countermeasure to this phenomenon, it is preferable to adjust the length of the joint portion 6b from the upper surface side of the bottom plate portion 6a. Therefore, it is necessary to measure the length of the horn tip 6 at which the horn tip 6 resonates with the ultrasonic LT horn 4 when the horn tip 6 is attached to the ultrasonic LT horn 4.

[0105] Fig.11 The figure shows the joint 6b of the ultrasonic LT horn 4 and the horn tip 6. The length h of the joint 6b from the upper surface side of the bottom plate 6a is measured when the natural vibration frequency f1 of the ultrasonic LT horn 4 and the natural vibration frequency f2 of the horn tip 6 are substantially equal, and this length (resonance length) is defined as L. At this time, the ultrasonic LT horn 4 and the horn tip 6 vibrate as one vibrating body.

[0106] At the resonant length L, if Fig.12As shown in the waveform of (a), when the ultrasonic LT horn 4 is displaced in one direction, the front end of the joint 6b of the horn welding tip 6 is displaced in the direction opposite to the one direction. Specifically, the point C in the figure of the ultrasonic LT horn 4 and the front end vibrate in opposite phases. Therefore, the force acting on the point C becomes larger, and there is a possibility that a gap will be generated between the ultrasonic LT horn 4 and the horn welding tip 6. In addition, regarding the actual numerical value, relative to the thickness w = 7 (mm) of the joint 6b, the length h (L) = 19 (mm), so the ratio h / w = 2.71.

[0107] Next, the natural frequencies f1 and f2 are made different by shortening the length h of the joint portion 6b of the horn welding tip 6. When the joint portion 6b is shortened, the natural frequency f2 of the horn welding tip 6 becomes higher. Fig.12 (b) shows the case where the length h of the joint 6b is set to L / 2 to L. Although the vibration is in the opposite phase, the front end of the joint 6b becomes a smaller vibration than when the resonance length is L. At this time, relative to the thickness w of the joint 6b = 7 (mm), for example, the length h = 14 (mm), so the ratio h / w = 2.00.

[0108] Fig.12 (c) shows the case where the length h of the joint 6b of the horn welding nozzle 6 is further shortened and the length h is set to L / 2. At this time, point C becomes a node of vibration (a node with zero amplitude), and the anti-phase between point C of the ultrasonic LT horn 4 and the front end of the joint 6b of the horn welding nozzle 6 is eliminated. Therefore, the workpiece W can be joined by the ultrasonic joining device 1 under this condition. However, point C and the front end of the joint 6b generate vibrations with different amplitudes. At this time, relative to the thickness w=7 (mm) of the joint 6b, the length h (L / 2)=9.5 (mm), so the ratio h / w=1.36.

[0109] Fig.12 (d) shows the case where the length h of the joint 6b of the horn welding tip 6 is further shortened and the length h is set to L / 3. Under this condition, the amplitude of the point C and the front end of the joint 6b of the horn welding tip 6 are substantially equal and move in the same direction. At this time, relative to the thickness w of the joint 6b = 7 (mm), the length h (L / 3) = 6.3 (mm), so the ratio h / w = 0.90.

[0110] Although it depends on the shape of the ultrasonic LT horn 4, the presence or absence of a thick wall portion, etc., when the thickness w of the joint portion 6b is constant, the length h of the joint portion 6b of the horn welding tip 6 is preferably less than half (1 / 2) of the resonant length L of the ultrasonic LT horn 4 and the horn welding tip 6, and more preferably 1 / 3 to 1 / 2. The ratio h / w of the thickness w of the joint portion 6b to the length h is preferably 1.5 or less (0<h / w≤1.5), and under this condition, the gap between the ultrasonic LT horn 4 and the horn welding tip 6 can be suppressed.

[0111] When the joint 6b is gradually shortened from the resonance length L, the length h of the joint 6b that becomes in phase can be confirmed by vibration analysis, so it is possible to actually conduct a trial. In addition, when the thickness w of the joint 6b is increased, the resonance length L becomes longer.

[0112] Next, refer to Fig.13 The attachment position of the horn tip 6 in the axial direction of the ultrasonic LT horn 4 will be described.

[0113] like Fig.13 As shown, the horn welding tip 6 is installed at a position where the end surface of the joint 6b is flush with the end surface of the front end portion 4b of the ultrasonic LT horn 4. Here, the vicinity of the center portion in the axial direction of the front end portion 4b of the ultrasonic LT horn 4 becomes a vibration node, so the displacement during vibration is small, but the stress (stretching stress) caused by the vibration is large. If the horn welding tip 6 is installed at a position with large stress, the threaded holes 41 and 42 of the front end portion 4b will expand slightly when the ultrasonic LT horn 4 is displaced in the extension direction.

[0114] On the other hand, the joint surface between the cylindrical portion 4a and the front end portion 4b of the ultrasonic LT horn 4 and the end surface of the joint portion 6b are located at the antinode of the vibration where the displacement amount is large during vibration, and the stress is small. Therefore, the screw 30 for fixing the horn welding tip 6 is preferably located at a position where the stress of the ultrasonic LT horn 4 is relatively small. For example, it is more preferable to locate the position where the stress of the portion where the screw 30 is located is 30% or less of the maximum value.

[0115] By installing the screw 30 at a position where stress is relatively small (position of the antinode of vibration), the threaded holes 41 and 42 of the ultrasonic LT horn 4 can be prevented from expanding, so that the screw will not loosen. For the above reasons, the horn welding tip 6 can also be located at a predetermined position in the front end portion 4b where stress is relatively small.

[0116] The present invention is not limited to the above-described embodiment, but can be implemented in various forms without departing from the gist of the invention.

[0117] The front end portion 4b of the ultrasonic LT horn 4 of the present embodiment is provided with a circular hole 4c (see Fig.14A ), but the threaded hole is shortened, so the fixing of the horn welding tip 6 to the ultrasonic LT horn 4 is insufficient. In addition, the wall thickness of the surface with the threaded hole of the front end portion 4b is thinned, which becomes a cause of cracks in the front end portion 4b. For example, when the horn welding tip 6 with three through holes is mounted on the front end portion 4b of the ultrasonic LT horn 4, it is necessary to shorten the threaded hole corresponding to the position of the screw 30b, so sometimes the tightening force of the screw 30b becomes insufficient (refer to Fig. 14B ).

[0118] Therefore, the front end portion 4b of the ultrasonic LT horn 4 may also be a form in which two circular holes 4c1 and 4c2 with a diameter smaller than the circular hole 4c are opened (ultrasonic LT horn 4') (see Fig.15A ).

[0119] like Fig. 15B As shown, a threaded hole corresponding to the screw 30b is formed between the two circular holes 4c1 and 4c2, so that the same screw tightening force as other threaded holes can be obtained. In addition, the horn welding tip 6 is fixed by three screws 30a to 30c, so the horn welding tip 6 can be reliably mounted on the front end 4b of the ultrasonic LT horn 4'.

[0120] The shape of the front end 4b of the ultrasonic LT horn 4' also affects the vibration amplitude in the longitudinal and torsional directions. It is known that, generally, when the area and the second polar moment of the cross section of the front end 4b of the ultrasonic LT horn 4' are reduced, the vibration amplitude increases.

[0121] From the rear end of the ultrasonic LT horn 4' ( Fig.15A The cross-sectional area (A) of the portion from the left end of the Fig.15A The larger the ratio (A / B) of the cross-sectional area (B) of the portion of the right end portion of the ultrasonic LT horn 4' is, the larger the longitudinal amplitude is. That is, if the cross-sectional area of ​​the front end portion 4b of the ultrasonic LT horn 4' is reduced, the value of the ratio (A / B) becomes larger, and the longitudinal vibration increases. This leads to an increase in the amplitude in the torsional direction.

[0122] In addition, the cross-sectional polar moment of the front end portion 4b of the ultrasonic LT horn 4' is given by (cross-sectional polar moment of the rectangular portion of the front end portion 4b) - (cross-sectional polar moment of the two circular holes of the front end portion 4b). In addition, the further away from the central axis of the front end portion 4b, the greater the cross-sectional polar moment of the circular holes 4c1 and 4c2 (the amount corresponding to the amount of the lengthening of the lever arm).

[0123] From the rear end of the ultrasonic LT horn 4' ( Fig.15A The second polar moment (C) of the cross section from the left end of the center to the rear end ( Fig.15AThe larger the ratio (C / D) of the second polar moment (D) of the section of the right end portion (of the front end portion 4b), the larger the amplitude in the torsional direction. Thus, by arranging the circular holes 4c1 and 4c2 of the front end portion 4b at a certain distance apart, the amplitude in the torsional direction can be enlarged.

[0124] In addition, if Fig.16 As shown, it is also possible to construct a structure in which threaded holes 43 and 44 are pre-set on a horizontally longer surface N (on the opposite side of the mounting surface M of the transformer welding nozzle 6) of the front end portion 4b of the ultrasonic LT transformer 4, so that a threaded balancer 35 (the "vibration adjustment component" of the present invention) can be installed and removed.

[0125] Conventionally, when a horn wider in the width direction relative to the front side, such as the ultrasonic LT horn 4, is vibrated under static pressure, the amplitude may be different at the left and right ends of the horn welding tip 6. This is considered to be due to the strain deformation at the ends caused by the overlap of different vibration modes. In addition, when welding is performed in this state, the welding strength of the workpiece W may be different at each end of the horn welding tip 6.

[0126] As a countermeasure, by installing a balancer 35 on the surface N of the front end 4b of the ultrasonic LT horn 4, the vibration amplitudes of the left and right ends of the horn welding tip 6 can be adjusted to be equal. Specifically, the balancer 35 as a counterweight is installed on the side with a larger vibration amplitude. The balancer 35 may also be a structure of a screw and a washer. In addition, in this case, it is preferable that the outer diameter of the washer is larger than the diameter of the screw head.

[0127] When the vibration amplitude of the left end ("L" in the figure) of the horn welding tip 6 is larger than the vibration amplitude of the right end ("R" in the figure), the vibration amplitudes of the left and right ends can be equalized by installing the balancer 35 in the left threaded hole 43. In addition, when the vibration amplitude of the right end of the horn welding tip 6 is larger than the vibration amplitude of the left end, the balancer 35 can be installed in the right threaded hole 44.

[0128] The balancer 35 is not limited to the surface N, and may be attached to the screw holes 45 and 46 on the side surface of the tip 4b of the ultrasonic LT horn 4 that does not interfere with the horn tip 6. In addition, a plurality of balancers 35 may be attached to the screw holes 43 to 46 for adjustment.

[0129] [Explanation of symbols]

[0130] 1: Ultrasonic bonding device; 2: Ultrasonic vibrator; 3: Ultrasonic amplifier horn; 3a: Flange; 4, 4': Ultrasonic LT horn; 4a: Cylindrical portion; 4b: Front end portion; 4c: Circular hole; 4d: Protrusion; 6, 16, 17, 18, 19, 20, 21: Horn welding nozzle; 6a, 16a, 17a, 18a, 19a, 20a, 21a: Bottom plate; 6b, 16b, 17b, 18b, 19b, 20b, 21b: Bonding Part; 7: anvil; 8: oscillating device; 10: pressurizing device; 12: sensor; 13: control device; 17c, 19c, 20c: thick wall part; 21c: rib; 30: screw; 35: balancer; 41~46: threaded hole; 61, 62, 161, 162, 171, 172, 181~184, 191~193, 201~212: through hole; 63, 173, 194: groove; P: protrusion; S: inclined slit; W: workpiece.

Claims

1. A horn welding nozzle for joining workpieces by ultrasonic joining, characterized in that: have: a bottom plate portion having a plurality of through holes for screws to pass through; and a joint portion protruding vertically from the bottom plate portion, A ratio h / w of a length h of the joining portion from the upper surface side of the bottom plate portion to a thickness w of the joining portion is 1.5 or less.

2. The horn welding nozzle according to claim 1, wherein: The engaging portion protrudes in a vertical direction from one end edge of the bottom plate portion extending in the longitudinal direction.

3. The horn welding nozzle according to claim 1, wherein: A thick wall portion is provided whose thickness gradually increases from the bottom plate portion toward a base end portion continuous with the joining portion.

4. The horn welding nozzle according to any one of claims 1 to 3, wherein: A groove portion is provided on a lower surface side of the bottom plate portion that contacts the surface of the ultrasonic horn.

5. An ultrasonic bonding device, characterized in that: have: A horn welding nozzle, comprising a bottom plate portion provided with a plurality of through holes for screws to pass through, and a joint portion protruding in a vertical direction from the bottom plate portion, wherein the length of the joint portion from the upper surface side of the bottom plate portion is less than half of the resonant length; and an ultrasonic horn capable of mounting said horn welding nozzle, A threaded hole corresponding to the through hole of the horn welding nozzle is provided on at least one side surface of the front end portion of the ultrasonic horn.

6. The ultrasonic bonding device according to claim 5, wherein: The front end portion is in a quadrangular prism shape.

7. The ultrasonic bonding device according to claim 5 or 6, wherein: The joint portion protrudes in a vertical direction from one end edge of the bottom plate portion extending in the longitudinal direction. The end surface of the front end portion is flush with the end surface of the joint portion of the horn welding nozzle.

8. The ultrasonic bonding device according to claim 5, wherein: The screw hole is provided at a position where stress is lower than a central portion in the axial direction of the front end portion.

9. The ultrasonic bonding device according to claim 5, wherein: A convex portion for preventing the horn welding tip from shifting relative to the front end portion is provided on a surface of the front end portion on which the horn welding tip is mounted.

10. The ultrasonic bonding device according to claim 5, wherein: The threaded hole provided at a position not interfering with the horn welding nozzle enables the vibration adjustment component to be attached and detached.

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