JP4075400B2 - Electrolytic capacitor manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an electrolytic capacitor, and more particularly to a method for manufacturing an electrolytic capacitor in which an external terminal is fixed to a sealing plate with rivets.
[0002]
[Prior art]
In general, in an electrolytic capacitor, for example, as shown in FIG. 5, a capacitor element 60 impregnated with an electrolyte is placed in an outer case 14, and the outer case 14 is sealed with a sealing plate 2. The external terminal 4 on the side is fixed by a rivet 6, and the electrode lead 62 on the capacitor element 60 side is connected by this rivet 6.
[0003]
For example, as shown in FIG. 6, the sealing plate 2 is provided with a hard insulating plate 16 on the inner surface side of the outer case 14 and an elastic insulating plate 18 on the outer surface side thereof, and includes a through hole 20 for attaching the rivet 6. ing. There is a method in which a rivet 6 is inserted into each of the through holes 21 and 20 of the external terminal 4 and the sealing plate 2, a washer 8 is attached to the rivet 6 protruding from the sealing plate 2, and an electrode lead 62 is fixed thereon by a washer 64. It is taken. The reason why the rivet 6 is fixed to the sealing plate 2 by the washer 8 is to keep the airtightness of the through hole 20 side and to prevent the outflow of the electrolyte into the outer case 14 as well as to prevent the electrolyte from flowing out. is there.
[0004]
[Problems to be solved by the invention]
By the way, in such a method of manufacturing an electrolytic capacitor, as shown in FIG. 7, a washer 8 is fitted to a rivet 6 projecting toward the hard insulating plate 16 side of the sealing plate 2, and the head 26 side of the rivet 6 is attached. A method in which the washer 8 is press-fitted into the rivet 6 by being installed on the base 10 and lowering the pressing die 12 into the washer 8 is employed. Japanese Patent No. 2666217 “Method of manufacturing electrolytic capacitor”, Japanese Patent No. 3185432 “Method of fixing external terminal”, Japanese Patent Publication No. 6-85384 “Method of caulking terminal of electrolytic capacitor”, Utility Model Registration No. No. 3056647, “Liquid-tight structure of terminal fittings with respect to insulating plate” has been proposed.
[0005]
In order to increase the pressure applied to the washer 8, if a protrusion 42 having a V-shaped cross section is formed on the pressing surface 40 of the pressing die 12 in the vicinity of the rivet 6, the protrusion 42 is pressed against the washer 8. The applied pressure can be increased locally. The V-shaped recess 48 is formed by the action of pressure. According to such a method, the washer 8 can be pressed against the sealing plate 2 side, but there is a risk that the washer 8 may be deformed, for example, a mortar-like warp is generated. In particular, when a thin material is used for the washer 8 in order to reduce the weight and improve the housing efficiency of the outer case, the mechanical strength of the washer 8 is lowered, and the deformation becomes remarkable.
[0006]
As described above, when the washer 8 is deformed, a gap 66 is generated on the contact surface between the hard insulating plate 16 and the washer 8 of the flat sealing plate 2, and the adhesion between the two is impaired. If such a gap 66 is generated, the electrolyte impregnated in the capacitor element 60 may invade, and the product characteristics of the electrolytic capacitor may become unstable.
[0007]
Accordingly, an object of the present invention is to provide a method for manufacturing an electrolytic capacitor in which a washer for fixing an external terminal to a sealing plate can be made thin and deformation of the washer is prevented.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the electrolytic capacitor manufacturing method of the present invention is enumerated with reference numerals as follows.
[0009]
In the method for manufacturing an electrolytic capacitor according to the first aspect of the present invention, the rivet (6) is inserted into the through hole (20) of the sealing plate (2) for sealing the outer case, and the washer (8) is pressed into the rivet. By fixing the external terminal (4) to the sealing plate by the washer and the rivet, the rivet is inserted into the electrode lead (62) of the capacitor element (60) and crimped. A method of manufacturing an electrolytic capacitor in which the electrode lead is electrically connected to the external terminal via the rivet, wherein the pressure applied in the vicinity of the rivet is locally applied to the pressurized surface (46) of the washer. A first die (42) that is strengthened to a pressing force and a pressing die (12) that is provided with a second protrusion (44) that locally enhances the applied pressure on the peripheral side of the washer. The serial washer, characterized in that pressurizing the sealing plate side.
[0010]
According to a second aspect of the present invention, there is provided an electrolytic capacitor manufacturing method according to the first aspect, wherein the first and second projecting portions are annularly formed concentrically around the rivet. It is formed or formed in an arc shape at a predetermined angular interval.
[0011]
According to a third aspect of the present invention, there is provided an electrolytic capacitor manufacturing method according to the first aspect, wherein the first and second projecting portions are erected on a concentric circle with the rivet as a center. It is characterized by being a plurality of protrusions.
[0012]
According to such a configuration, deformation of the washer that fixes the rivet to the sealing plate can be prevented from being deformed, the washer can be thinned, and adhesion between the washer and the sealing plate can be improved. Intrusion can be prevented and product characteristics can be stabilized. Moreover, since the caulking dimension at the time of tab connection can be shortened, the accommodation efficiency of an exterior case can be improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The electrolytic capacitor manufacturing method of the present invention includes, for example, a base 10 as a means for crimping a washer 8 attached to a rivet 6 as a fixing means for fixing an external terminal 4 to a sealing plate 2, as shown in FIG. A pressing die 12 is used.
[0014]
The sealing plate 2 is means for sealing the outer case 14 as shown in FIGS. 5 and 6, for example. In this embodiment, the hard insulating plate 16 is provided on the inner side and the elastic insulating plate 18 is provided on the outer side. A through-hole 20 through which the rivet 6 passes is formed in advance. For example, a bakelite plate is used as the hard insulating plate 16, and a rubber plate is used as the elastic insulating plate 18, for example.
[0015]
The external terminal 4 attached to the sealing plate 2 includes, for example, a claw portion 24 at one end of a plate-like fixing portion 22 provided with a through hole 21 as shown in FIGS. The present invention is not limited to such external terminals 4.
[0016]
The rivet 6 is formed of a material similar to the electrode material of the capacitor element, for example, aluminum, and has a cylindrical shaft portion 28 protruding from the center of a disc-shaped head portion 26. The diameter of the portion is reduced by forming the tapered surface 30 or the like, and the fitting of the washer 8 is facilitated.
[0017]
The washer 8 is an annular body formed of aluminum or the like, similar to the rivet 6, and having a through hole 32 in the center.
[0018]
The base 10 on which the sealing plate 2 is placed is a support means for stably supporting the sealing plate 2, and includes a recess 34 that accommodates the head 26 of the rivet 6 protruding from the sealing plate 2, and the external terminal 4. A recess 36 for inserting the claw portion 24 is formed.
[0019]
Further, the pressing die 12 includes a through hole 38 for allowing the rivet 6 to escape, and a pressing surface 40 on the lower surface. The pressurizing surface 40 is formed with a first protrusion 42 that increases the pressure on the vicinity of the rivet 6 and a second protrusion 44 that increases the pressure on the periphery of the washer 8. The pressing surface 40 of the pressing die 12 is configured as shown in FIG. 2, for example, an annular protrusion 42 having a mountain cross section is formed on the center side, and an annular protrusion having a rectangular cross section is formed concentrically with the protrusion 42. A protruding portion 44 is formed.
[0020]
Then, the through-hole 21 of the fixing portion 22 of the external terminal 4 is aligned with the through-hole 20 of the sealing plate 2 on the elastic insulating plate 18 side so as to penetrate the rivet 6, and the head 26 is fixed to the fixing portion of the external terminal 4 22 is installed on the base 10 in this state.
[0021]
Next, the washer 8 is attached to the shaft portion 28 of the rivet 6 protruding from the sealing plate 2, the pressing die 12 is lowered, the washer 8 is crimped on the sealing plate 2 with a predetermined pressure, and the pressing die 12 is moved backward. An arrow F indicates the moving direction of the pressing die 12.
[0022]
By this process, the protrusions 42 and 44 on the pressing surface 40 side of the pressing die 12 are pressed onto the washer 8 to locally increase the pressing force on the pressed surface 46 of the washer 8. As a result, the washer 8 is formed with a V-shaped recess 48 corresponding to the protrusion 42 and a step 50 corresponding to the protrusion 44.
[0023]
As described above, the washer 8 has a predetermined width in the diameter direction of the pressing surface 40 of the pressing die 12, and in this embodiment, the protruding portion 42 in the vicinity of the shaft portion 28 of the rivet 6, and the protruding portion on the peripheral side of the washer 8. As a result of forming 44, the pressing force is increased at predetermined intervals in the diameter direction of the washer 8, and the washer 8 is press-fitted into the rivet 6 without causing deformation such as warpage of the washer 8, and is in close contact with the sealing plate 2. Can be made.
[0024]
In the electrolytic capacitor provided with the washer 8 thus fixed, no gap is formed between the washer 8 and the sealing plate 2, so that the infiltration of the electrolyte impregnated in the capacitor element can be prevented, and the product characteristics Can be stabilized.
[0025]
Further, if the washer 8 is press-fitted into the rivet 6 using such a pressing die 12, the washer 8 is not deformed, so that the material of the washer 8 can be made thin, which can contribute to weight reduction. Moreover, since the caulking dimension at the time of tab connection can be shortened, the accommodation efficiency of an exterior case can be improved.
[0026]
In addition, as a form of the pressing surface 40 of the pressing die 12, for example, as shown in FIG. 3, a plurality of arcuate protrusions 42 and 44 may be formed at predetermined angular intervals, and as shown in FIG. As described above, a plurality of conical protrusions 42 and a plurality of columnar protrusions 44 may be used.
[0027]
Further, the protruding portion 44 may be formed inside the periphery of the washer 8.
[0028]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
a It is possible to locally increase the pressure applied to the washer that fixes the rivet to the sealing plate, and to prevent the bias of the pressure applied to the washer, thereby preventing deformation such as warpage.
b Even if the washer is thin, deformation such as warping can be prevented.
c The adhesion between the washer and the sealing plate can be enhanced, so that the intrusion of the electrolyte can be prevented and the product characteristics can be stabilized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a method for producing an electrolytic capacitor according to the present invention.
FIG. 2 is a perspective view showing an example of a pressing surface of a pressing die.
FIG. 3 is a perspective view showing a modification of the pressing surface of the pressing die.
FIG. 4 is a perspective view showing a modification of the pressing surface of the pressing die.
FIG. 5 is a side view showing the electrolytic capacitor shown with a part cut away;
FIG. 6 is an exploded perspective view showing a fixing structure with rivets to the sealing plate.
FIG. 7 is a cross-sectional view showing a washer caulking process for rivets on a sealing plate.
[Explanation of symbols]
2 Sealing plate 4 External terminal 6 Rivet 8 Washer 12 Stamping die 20 Through-hole 40 Pressure surface 42 First protrusion 44 Second protrusion 46 Surface to be pressed

Claims (3)

A rivet is inserted through the through hole of the sealing plate that seals the outer case, and a washer is pressed against and fixed to the rivet. An electrolytic capacitor manufacturing method for electrically connecting the electrode lead to the external terminal through the rivet by inserting and crimping the electrode lead of the capacitor element,
A second protrusion for locally increasing the pressure on the peripheral side of the washer, and a first protrusion for locally increasing the pressure on the vicinity of the rivet with respect to the surface to be pressed of the washer. A method of manufacturing an electrolytic capacitor, wherein the washer is pressurized toward the sealing plate by a pressing die provided with a portion. 2. The electrolytic capacitor according to claim 1, wherein the first and second projecting portions are formed in an annular shape on a concentric circle with the rivet as a center, or are formed in an arc shape at a predetermined angular interval. Manufacturing method. 2. The method of manufacturing an electrolytic capacitor according to claim 1, wherein the first and second protrusions are a plurality of protrusions standing on a concentric circle with the rivet as a center.

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