JP2004079564A - Ultrasonic welding horn for electrolytic capacitor and method of manufacturing electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a joint welded by ultrasonic bonding between a terminal rivet and a tab to be improved in weld strength and connection reliability. <P>SOLUTION: The tab 34 led out from a capacitive element 22 is laid on the terminal rivet 32 where the the tab 34 is to be welded, and ultrasonic energy is given by an electrolytic capacitor ultrasonic welding horn to the weld part 40 of the terminal rivet 32 to the tab 34 as the tab 34 is pressed. In the electrolytic capacitor ultrasonic welding horn, a horn unit 4 provided with a plurality of pointed projections 14 at its top 12, and at least, one or more of the projections 14 are each set higher than the thickness t of the tab 34. A method of manufacturing an electrolytic capacitor comprises a process of fixing the terminal rivet 32 to the tab 34 by ultrasonic welding by the use of the ultrasonic welding horn. <P>COPYRIGHT: (C)2004,JPO

Description

【００３８】
この実験結果から明らかなように、従来ホーンでは、電解液の有無を問わず、タブ３４にズレや一部に破損が発生した。これに対し、実施例では、電解液の付着の有り、無しに拘わらず、タブ３４のズレや破損は生じていない。実施例では、溶接時間が短縮され、溶接に要する超音波エネルギを大幅に低減でき、タブ３４のズレや破損がないことから、接続強度を向上させることができ、信頼性の高い溶接が得られる。
【００３９】
なお、実施の形態では、各突部１４を正四角錐状にしたが、円錐状としてもよく、また、突部１４は、尖鋭部を持つ円柱状又は角柱状等、柱状部を備えてもよい。柱状部の高さを加減することで、所望の溶接深度に設定することができる。
【００４０】
【発明の効果】
以上説明したように、本発明によれば、次の効果が得られる。
（ａ）　複数の突部を以て溶接を行うことができるとともに、少なくとも１つの突部の高さをタブの厚みより高く設定しているので、ターミナルリベットとタブとの溶接強度を向上させることができ、溶接時のタブの変形やズレを防止でき、接続の信頼性の向上を図ることができる。
（ｂ）　溶接時間を大幅に低減できるとともに、溶接に要する超音波エネルギを小さくでき、溶接によるタブの亀裂、破断等の損傷の発生を防止でき、タブとターミナルリベットとの溶接の信頼性を高めることができる。
（ｃ）　溶接時間や溶接時の超音波エネルギを削減できるため、ホーン部の突部の先端部分を磨耗から防護でき、ホーン寿命を延ばすことができるとともに、安定した溶接を長期間に亘って維持することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る超音波溶接ホーンを示す側面図である。
【図２】超音波溶接ホーンのホーン部を示す平面図である。
【図３】図２に示すホーン部の各断面を示し、（Ａ）は図２のＩＩＩＡ−ＩＩＩＡ線断面図、（Ｂ）は図２のＩＩＩＢ−ＩＩＩＢ線断面図である。
【図４】本発明の実施の形態に係る電解コンデンサの製造方法における製造途上の電解コンデンサの一部を示す図である。
【図５】ターミナルリベットとタブとの溶接を示す図である。
【図６】ターミナルリベットとタブとの溶接部を示す部分平面図である。
【図７】従来の超音波溶接ホーン及び電解コンデンサの製造方法を示す側面図である。
【符号の説明】
４　ホーン部
１２　頂部
１４　突部
１８　傾斜部
２０　面取り部
２２　コンデンサ素子
２８　封口板
３２　ターミナルリベット
３４　タブ
４０　溶接部
４２　凹部
４４　立壁部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic welding horn used for ultrasonic welding of a terminal rivet of an electrolytic capacitor such as an aluminum electrolytic capacitor and a lead (tab), and a method of manufacturing an electrolytic capacitor using the ultrasonic welding horn.
[0002]
[Prior art]
In aluminum electrolytic capacitors, terminal rivets are fixed to the sealing plate of the outer case that encloses the capacitor element.A tab drawn out of the capacitor element is attached to this rivet by caulking with a washer, and the tab is attached to the end of the rivet. The metal connection by the sound wave provides an electrical connection as well as a mechanical connection between the terminal rivet and the tab. The complementation of such mechanical metal-to-metal bonding by ultrasonic bonding is to realize a highly reliable bonding state. As a technique for joining such a tab and a terminal rivet using ultrasonic waves, for example, there is Japanese Patent No. 2811732 “Method of manufacturing aluminum electrolytic capacitor”.
[0003]
[Problems to be solved by the invention]
By the way, in this method for manufacturing an aluminum electrolytic capacitor, an ultrasonic welding horn for applying ultrasonic energy to a member to be welded is used, and the ultrasonic welding horn has a plurality of truncated conical protrusions formed thereon. Also, there are some in which a plurality of small projections are formed. Since the height of the projections of these horns is lower than the thickness of the tab, and ultrasonic welding is performed on each top surface of the plurality of projections, a boundary surface is created between the joined rivet and the tab, so that both of them are formed. Insufficient connection strength. In particular, in the case of a truncated cone-shaped projection, since the pressing surface is a flat surface, it is difficult to press the tab at one point. In order to increase the connection strength, it is conceivable to increase the ultrasonic energy required for the welding process. When multiple tabs are overlapped and welded, the ultrasonic energy increases as the thickness of the tabs and the number of layers increase. It is necessary to make the application time of the ultrasonic wave longer.
[0004]
However, if the tab cannot withstand the increased ultrasonic energy, the tab deforms, and the amount of deformation increases with the amount of ultrasonic energy, causing cracks and breaks at and near the welded portion, and in some cases, Causes a gap between the tabs. In particular, if the tabs are misaligned in the width direction, the welding surface is reduced, resulting in poor welding or a decrease in connection strength, which may reduce the reliability of the connection.
[0005]
Therefore, an object of the present invention is to provide an ultrasonic welding horn for an electrolytic capacitor capable of increasing the strength of ultrasonic bonding between a terminal rivet and a tab and improving connection reliability, and a method of manufacturing an electrolytic capacitor. And
[0006]
[Means for Solving the Problems]
The configuration of the ultrasonic welding horn for an electrolytic capacitor and the method for manufacturing an electrolytic capacitor according to the present invention which has solved the above problems is as follows.
[0007]
In the ultrasonic welding horn for an electrolytic capacitor according to the present invention, the ultrasonic welding horn for an electrolytic capacitor according to the first aspect of the present invention overlaps a tab 34 drawn from the capacitor element 22 on a terminal rivet 32 to be welded, and adds the tab. An ultrasonic welding horn for an electrolytic capacitor for applying ultrasonic energy to a welding portion 40 of the terminal rivet and the tab while pressing, comprising a plurality of projections 14 having a sharp portion at a top portion 12 of the horn portion 4, At least one or more of the projections is set to be higher than the thickness of the tab.
[0008]
That is, when the sharp portions of the protrusions are at the same height, a plurality of protrusions simultaneously contact the welded portion of the tab overlapped on the terminal rivet to be welded, and the sharp portions of each protrusion are It is positioned on the tab by pressurization, and ultrasonic welding is started from each sharp part. By maintaining the pressurization, a plurality of protrusions simultaneously enter the softened welded portion, and ultrasonic welding is performed.
[0009]
Also, since at least one of the plurality of protrusions is set higher than the thickness of the tab, the protrusion is selectively brought into contact with the welded portion of the tab, and the sharp portion of each protrusion is formed. It is positioned on the tab by pressurization, and ultrasonic welding is started from the sharp part. By maintaining the pressurization, a plurality of protrusions simultaneously enter the softened weld, and at least one of the protrusions enters the terminal rivet beyond the tab, and ultrasonic welding is performed.
[0010]
As described above, when ultrasonic welding is performed by each projection of the ultrasonic welding horn, ultrasonic energy is concentrated on the sharp portion of each projection and supplied to the tab and the terminal rivet, so that the welded portion is sharp. The joining surface between the metal on the tab side and the metal on the rivet side is integrated, the joining strength between the terminal rivet and the tab is increased, and a highly reliable joining state is obtained. As a result, the welding time can be reduced and the ultrasonic energy required for welding can be reduced, and sharpening of the welded portion also contributes to preventing displacement of the tab.
[0011]
Further, by using such an ultrasonic welding horn, the welding time and welding energy can be reduced, the ultrasonic welding horn can be protected from abrasion, and its service life can be extended.
[0012]
The ultrasonic welding horn for an electrolytic capacitor according to the present invention is characterized in that the projection has a columnar portion. That is, a columnar portion is provided, and the height of the columnar portion can be set arbitrarily to separate the welded portions.
[0013]
In the ultrasonic welding horn for an electrolytic capacitor according to the present invention, the ultrasonic welding horn for an electrolytic capacitor according to claim 3 includes an inclined portion 18 formed of a pyramidal surface formed on a peripheral side of the projection, and a chamfered to the inclined portion. It is characterized by having a part 20. That is, since the corners of the horn part are obtuse by the inclined part and the chamfered part, the adhesion with the tab after welding can be prevented, and the removal becomes easy.
[0014]
In the method for manufacturing an electrolytic capacitor according to the present invention, in the method for manufacturing an electrolytic capacitor according to the fourth aspect, a tab 34 pulled out from the capacitor element 22 is superimposed on a rivet (terminal rivet 32) penetrating through the sealing plate 28 and fixed. A method for manufacturing an electrolytic capacitor to be welded by ultrasonic energy, comprising a plurality of projections 14 having a sharp portion at a top 12 of a horn portion 4, at least one of the projections being set higher than the thickness of the tab. Applying ultrasonic energy from the ultrasonic welding horn to the welding portion 40 between the tab and the rivet while abutting the ultrasonic welding horn against the tab on the rivet and pressing the ultrasonic welding horn; And welding the tab to each other.
[0015]
That is, according to the method for manufacturing an electrolytic capacitor, the ultrasonic welding horn for an electrolytic capacitor described above suppresses deformation and displacement of a tab during welding, and provides a high welding strength and a highly reliable connection state. In the electrolytic capacitor, a terminal structure having a resistance to vibration stress can be realized.
[0016]
In the method for manufacturing an electrolytic capacitor according to the present invention, in the method for manufacturing an electrolytic capacitor according to claim 5, the plurality of recesses 42 are formed by the protrusions 14 by a process of welding the rivet and the tab. The vertical wall portion 44 is formed on the upper surface. That is, it is possible to obtain a secure fixing state between the rivet and the tab and to prevent a decrease in mechanical strength of the welded portion.
[0017]
In the method for manufacturing an electrolytic capacitor according to the present invention, the method for manufacturing an electrolytic capacitor according to claim 6 is characterized in that, during welding, ultrasonic energy of the ultrasonic welding horn is applied to the tab in the same direction as the tab. I do. That is, since the ultrasonic vibration is applied in the same direction as the tab, the tab can be prevented from shifting in the width direction, and the connection range between the rivet and the tab can be widened.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an ultrasonic welding horn for an electrolytic capacitor according to an embodiment of the present invention.
[0019]
This ultrasonic welding horn for an electrolytic capacitor has a single or plural horn portions 4 formed at the tip of a horn formed in a cross shape using a metal material such as steel, and an ultrasonic wave (not shown). In this configuration, ultrasonic energy is applied from a vibration source.
[0020]
Each horn portion 4 has, for example, as shown in FIG. 2, as a plurality of protrusions having sharp portions having the same or different heights, as shown in FIG. The projection 14 includes a recess 16 having a V-shaped cross section as a recess that partitions the projections 14. 3 shows each section of the horn part shown in FIG. 2, FIG. 3 (A) is a section taken along line IIIA-IIIA in FIG. 2, and FIG. 3 (B) is a section taken along line IIIB-IIIB in FIG. is there.
[0021]
The protrusion 14 is a square pyramid having a point-like sharp part with a square bottom surface, and has an acute apex angle, and the angle θ ₁ is, for example, 60 ° to form the protrusion 14. Each of the side portions is an isosceles triangle. The height h of the projection 14 is set in accordance with the thickness t and the welding depth of the tab (FIG. 5) which is the member to be welded, and the height h of the projection 14 is set higher than the thickness t of the tab. ing. In this case, the top 12 is formed with a projection 14 composed of four regular quadrangular pyramids, in other words, the top 12 is formed by the four projections 14. In this embodiment, the projections 14 of the same height h, but by setting the apex angle at the same angle theta _1, the projections 14 may have different heights, the angle theta ₁ is also the projections 14 may be different. The concave portion 16 is formed between the protrusions 14 and has a cross shape, with the bottom edge of the protrusion 14 being the deepest portion. The protrusions 14 having a thickness greater than the thickness t of the tab need not be all of the plurality of protrusions 14, but may be one or more.
[0022]
Further, between the lower edge of the protrusion 14, that is, between the top 12 and the middle part of the columnar portion 10, there is formed an inclined portion 18 formed of a pyramidal surface rising toward the protrusion 14 with a gentle inclination. Reference numeral 18 includes four trapezoidal surfaces having the top 12 side as the upper bottom, and four chamfers 20 formed of isosceles triangles. The side surface and the inclined portion 18 of the projecting portion 14 forms a V-shaped bent surface, there is the angle theta _2.
[0023]
Next, FIGS. 4 and 5 show a method of manufacturing an electrolytic capacitor according to an embodiment of the present invention.
[0024]
The electrolytic capacitor includes an outer case 24 in which the capacitor element 22 is sealed, and an opening 26 of the outer case 24 is sealed by a sealing plate 28. The sealing plate 28 is formed of a hard synthetic resin plate, and an O-ring 30 is attached to the upper edge as a sealing member.
[0025]
A terminal rivet 32 constituting an external terminal is penetrated and fixed to the sealing plate 28 by insert molding into the sealing plate 28, and is pulled out from the terminal rivet 32 protruding inside the sealing plate 28 and the capacitor element 22. A plurality of strip-shaped tabs 34 made of a metal material such as aluminum are used as the lead leads. The terminal rivets 32 are inserted into the through holes 36 (FIG. 5) formed in the tabs 34 and It is fixed by swaging the fitted washer 38. In this case, the end side of the tab 34 is folded and overlapped with the end side of the terminal rivet 32.
[0026]
As shown in FIG. 5, the horn portion 4 of the ultrasonic welding horn according to the present invention (FIGS. 1 and 2) is brought into contact with the tab 34 superimposed on the terminal rivet 32, and is fixed by a fixing means (not shown). Ultrasonic energy is applied to the horn portion 4 together with the pressing force from an ultrasonic welding source (not shown), as shown by an arrow F, opposite to the terminal rivet 32 of the sealing plate 28 positioned and fixed. In this case, the height h of the protrusion 14 is set to be higher than the thickness t of the tab 34 as the member to be welded. That is, these magnitude relations are h> t.
[0027]
In this ultrasonic welding, the projections 14 of the same height of the horn portion 4 are brought into contact with the tabs 34 overlapped on the terminal rivets 32, and the sharp portions thereof are positioned on the tabs 34 by pressurization. Ultrasonic welding is started. When the pressurization is continued, each projection 14 enters the metal constituting the tab 34 softened by the ultrasonic energy by the height h, and at this time, the tab 34 bent along each projection 14 projects. It enters the terminal rivet 32 together with the part 14. At this time, the metal of the tab 34 enters the recess 16 between the projections 14, and the main welding portion in the welded portion 40 is formed by the projection 14, so that the tab 34 is welded to the terminal rivet 32. , A welded portion 40 is formed. In this embodiment, since the height h of the protrusion 14 is higher than the thickness t of the tab 34, the protrusion 14 enters inside the end face of the terminal rivet 32 during welding, and as a result, the deep portion of the terminal rivet 32 The terminal rivet 32 and the tab 34 are welded together with the tab 34, so that extremely high connection strength can be obtained.
[0028]
In addition, ultrasonic welding is performed at each of the protrusions 14 of the horn portion 4, and the ultrasonic energy is concentrated on the welded portion 40 centering on the tip of each of the protrusions 14, the welded portion is sharpened, and the metal on the tab 34 side is sharpened. The joining surface between the terminal rivet 32 and the metal on the terminal rivet 32 side is integrated, and the joining strength between the terminal rivet 32 and the tab 34 is increased. As a result, a highly reliable bonding state can be obtained. According to such ultrasonic welding, welding time and ultrasonic energy required for welding can be reduced, and sharpening of the welding portion 40 by the projection 14 can prevent displacement of the tab 34.
[0029]
Also, when ultrasonic energy is applied to the tab 34 centering on the projection 14 having a sharp portion, the welded portion is sharpened, but even if a phenomenon in which the laminated tab 34 warps around this portion occurs instantaneously. Since the sharp portions of the projections 14 are spaced apart from each other, the area of the welded portion 40 of the tab 34 or the vicinity thereof is pressed, so that deformation of the tab 34 such as warpage is suppressed. Moreover, in this case, the welding portion is formed as a plurality of protrusions, and is formed by the four protrusions 14 and spreads over most of the width direction of the tab 34, so that the welding portion 40 becomes the entire end face of the terminal rivet 32. As a result, a welding state with a high joining strength is obtained, and the displacement of the tab 34 can be prevented.
[0030]
In the ultrasonic welding using the horn portion 4, for example, as shown in FIG. 6, a plurality of regular square pyramid-shaped concave portions 42 corresponding to the protrusions 14, The plurality of upright wall portions 44 that partition the adjacent side of each of the recesses 42 are formed by the recesses 16. The space defined by the concave portions 16 between the protrusions 14 of the horn portion 4 functions as a molten metal pool on the tab 34 side, and the standing wall portion 44 is formed of metal that has entered the space of the concave portions 16. The height of the standing wall portion 44 matches the outer surface of the tab 34. In this case, the height of the standing wall portion 44 may be set back within the plane of the tab 34.
[0031]
If an ultrasonic welding horn having such a horn portion 4 is used, strong welding can be performed even if the welding time and welding energy are reduced, and the welding time can be shortened, so that excessive deformation of the tab 34 can be prevented. In addition, the ultrasonic welding horn can be protected from abrasion and its service life can be extended.
[0032]
【Example】
In the ultrasonic welding horn according to the embodiment of the present invention, for example, the angle (θ ₁ ) of the apex angle of the protrusion 14 made of four regular quadrangular pyramids on the horn part 4 is 60 °, and the height (h) is 1.4 mm. And the height of the chamfered portion 20 was 1 mm.
[0033]
The terminal rivet 32 as a member to be welded had a diameter φ of 4 mm, and the tab 34 was formed by stacking six chemical tabs having a thickness of 0.2 mm and a width of 7 mm. That is, since the total thickness (t) of the tab 34 is 1.2 mm, the height (h) of the projection 14 of the horn portion 4 is only 0.2 mm from the total thickness (t) of the tab 34 = 1.2 mm. It is set high.
[0034]
The welding conditions were fixed at a pressing force of 4 kg (gauge pressure), the ultrasonic vibration was set in the same direction as the longitudinal direction of the tab 34, and the electrolyte was attached to the tab 34, and the electrolyte was not attached. Set the state.
[0035]
Further, as a conventional horn of a comparative example, for example, as shown in FIG. 7, a horn portion having a large number of small projections 48 formed on a horn portion 46 is used. That is, the terminal rivet 32 is passed through the through hole 36 of the tab 34, the tab 34 is fixed to the terminal rivet 32 by caulking the washer 38, and the small projection 48 of the horn portion 46 is added to the folded tab 34. Welding was performed by applying ultrasonic energy while applying a pressure F.
[0036]
Table 1 shows the welding results under these conditions.
[0037]
[Table 1]

[0038]
As is clear from the experimental results, in the conventional horn, the tab 34 was displaced or partially damaged regardless of the presence or absence of the electrolytic solution. On the other hand, in the embodiment, no displacement or breakage of the tab 34 occurs regardless of the presence or absence of the adhesion of the electrolytic solution. In the embodiment, the welding time is shortened, the ultrasonic energy required for welding can be significantly reduced, and there is no displacement or breakage of the tab 34, so that the connection strength can be improved, and highly reliable welding can be obtained. .
[0039]
In the embodiment, each of the protrusions 14 has a regular quadrangular pyramid shape. However, the protrusions 14 may have a conical shape, and the protrusion 14 may include a columnar portion such as a columnar shape having a sharp portion or a prismatic shape. . By adjusting the height of the columnar portion, a desired welding depth can be set.
[0040]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
(A) Welding can be performed with a plurality of protrusions, and the height of at least one protrusion is set higher than the thickness of the tab, so that the welding strength between the terminal rivet and the tab can be improved. In addition, the deformation and displacement of the tab during welding can be prevented, and the reliability of the connection can be improved.
(B) The welding time can be greatly reduced, the ultrasonic energy required for welding can be reduced, and damage such as cracking or breakage of the tab due to welding can be prevented, and the reliability of welding between the tab and the terminal rivet can be improved. be able to.
(C) Since the welding time and ultrasonic energy during welding can be reduced, the tip of the horn projection can be protected from abrasion, the horn life can be extended, and stable welding can be maintained for a long period of time. can do.
[Brief description of the drawings]
FIG. 1 is a side view showing an ultrasonic welding horn according to an embodiment of the present invention.
FIG. 2 is a plan view showing a horn portion of the ultrasonic welding horn.
3A and 3B show cross sections of the horn shown in FIG. 2, wherein FIG. 3A is a cross sectional view taken along the line IIIA-IIIA of FIG. 2, and FIG. 3B is a cross sectional view taken along the line IIIB-IIIB of FIG.
FIG. 4 is a diagram showing a part of the electrolytic capacitor in the process of being manufactured in the method for manufacturing an electrolytic capacitor according to the embodiment of the present invention.
FIG. 5 is a diagram showing welding between a terminal rivet and a tab.
FIG. 6 is a partial plan view showing a welded portion between the terminal rivet and the tab.
FIG. 7 is a side view showing a conventional method for manufacturing an ultrasonic welding horn and an electrolytic capacitor.
[Explanation of symbols]
4 Horn 12 Top 14 Projection 18 Inclination 20 Chamfer 22 Capacitor element 28 Sealing plate 32 Terminal rivet 34 Tab 40 Weld 42 Concave 44 Standing wall

Claims (6)

An ultrasonic welding horn for an electrolytic capacitor, which superimposes a tab drawn out of a capacitor element on a terminal rivet to be welded and applies ultrasonic energy to a welding portion between the terminal rivet and the tab while pressing the tab. ,
An ultrasonic welding horn for an electrolytic capacitor, comprising: a plurality of protrusions having a sharp portion at a top of a horn portion, wherein at least one of the protrusions is set to be higher than a thickness of the tab. 2. The ultrasonic welding horn for an electrolytic capacitor according to claim 1, wherein said projection has a columnar portion. 2. The ultrasonic welding horn for an electrolytic capacitor according to claim 1, further comprising an inclined part formed of a pyramid surface formed on a peripheral side of the protrusion, and a chamfered part on the inclined part. A method for manufacturing an electrolytic capacitor in which tabs drawn from a capacitor element are overlapped on a rivet fixed through a sealing plate and welded by ultrasonic energy,
An ultrasonic welding horn provided with a plurality of projections having a sharp portion at the top of the horn, wherein at least one of the projections is set to be higher than the thickness of the tab, is applied by contacting the tab on the rivet. A process of applying ultrasonic energy from the ultrasonic welding horn to the welding portion between the tab and the rivet while applying pressure;
Processing to weld the rivet and the tab,
A method for manufacturing an electrolytic capacitor, comprising: The method for manufacturing an electrolytic capacitor according to claim 4, wherein the rivet and the tab are welded to form a plurality of recesses by the protrusion and an upright wall portion within an interval between the protrusions. 5. The method according to claim 4, wherein ultrasonic energy of the ultrasonic welding horn is applied to the tab in the same direction as the tab during welding.

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