JP4582291B2 - Electrolytic capacitor manufacturing method - Google Patents

Description

  The present invention relates to an electrolytic capacitor having a bottomed cylindrical shape and having a capacitor element housed in an outer case having opposed long sides and a curved portion continuous to the long sides, that is, an outer case having an oval cross-sectional shape. It relates to the manufacturing method.

  Conventionally, a flat type electrolytic capacitor has been used. This electrolytic capacitor is configured by using, for example, a capacitor element 1 formed in an elliptical shape or an oval shape as shown in FIG. A sealing member 3 is inserted together with the capacitor element 1 into a metallic exterior case 2 formed in accordance with the shape of 1 and the opening is sealed. The sealing member 3 is formed with a through-hole for penetrating and holding the rod-like lead terminal 4 drawn from the end face of the capacitor element 1. Then, prior to sealing the outer case 2, the sealing member 3 is fixed by penetrating the lead terminal 4 through the end surface portion of the capacitor element 1.

  When caulking the oval outer case 2 having such a long side portion and a curved portion, the radius of curvature is naturally different between the long side portion and the curved portion. Even if a molding pressure is applied, it is difficult to apply a molding force evenly from the shape, and a molding state for obtaining the required airtightness cannot be obtained.

  Therefore, the sealing of the outer case 2 has a guide surface that matches the opening of the outer case 2 that is formed in an oval shape, and has a molding surface that is curved inward by extending the guide surface. An application has been filed for a sealing method that realizes reliable sealing using a mold.

Japanese Patent Publication No. 3-71764

  However, in the sealing method disclosed in Japanese Patent Publication No. 3-71764, sufficient sealing strength may not be obtained depending on the size and hardness of the outer case 2. That is, when a molding die having a guide surface and a molding surface that match the opening of the oval outer case 2 is pressed against the opening of the outer case 2, that is, the length of the corresponding outer case 2 in the molding die. Since the molding surface for caulking the side portion and the curved portion is formed on the same surface, when caulking with this mold, the opening portion is deformed into an arc shape by caulking in the curved portion of the outer case 2, Since stress concentrates on the inner surface of the curved portion, the opening portion expands and is sufficiently pressed against the sealing member 3, but such a phenomenon does not occur in the long side portion of the exterior case 2, so There is a case where caulking wrinkles are generated near the boundary between the long side portion which is difficult and the extending curved portion, and the sealing performance is impaired.

  In addition, even if the long side portion and the curved portion of the outer case 2 are simultaneously crimped on the same surface as described above, the long side portion is difficult to extend, so the apparent size of the outer shape of the outer case 2 is the long side. Both the part and the curved part are uniform, but the sealing strength is not uniform. Such non-uniform sealing strength is particularly likely to occur when the outer case 2 has a high hardness.

  When the oval outer case 2 is caulked with a molding die, caulking wrinkles are generated near the boundary between the curved portion and the long side portion, and the sealing strength between the curved portion and the long side portion is poor. Uniformity tends to cause the above-described problem particularly when caulking using the outer case 2 in which the dimensional ratio between the short side and the long side of the oval outer case 2 exceeds 1: 3.

  In addition, instead of caulking with a caulking mold, even if a rotary mold is pressed against the opening of the outer case 2, the wrinkles are generated near the boundary between the long side portion and the curved portion. Insufficient caulking at the long side may impair sealing performance.

  The present invention provides an electrolytic capacitor manufacturing method for easily and surely crimping an exterior case 2 composed of a long side portion such as an oval cross section and a curved portion, and achieving a highly reliable sealing state. Objective.

In order to solve the above-described problems, the electrolytic capacitor manufacturing method of the present invention is applied to a bottomed cylindrical outer case having an oblong cross section having a pair of opposed long side portions and a curved portion continuous with the long side portions. In a method of manufacturing an electrolytic capacitor that houses a capacitor element, inserts a sealing member into the opening of the outer case, and performs crimping on the entire periphery of the opening of the outer case, the curved portion or the long side portion of the outer case is added. After the tightening process is performed, the long side portion or the curved portion remaining as the unswaged portion is crimped . The caulking process is characterized in that after the caulking process of the curved portion of the outer case, the long side part of the outer case is caulked. The outer case having an oval cross section is characterized in that the dimensional ratio between the short side and the long side is 1: 3 or more.

  According to the present invention, when performing caulking processing on the entire periphery of the opening of the outer case, the curved portion of the outer case where the opening sufficiently extends and closely contacts the sealing member, and the curved portion is difficult to extend. Compared with the long side part of the fragile outer case, by separately performing the caulking process, it is possible to increase the molding accuracy near the boundary between the curved part and the long side part of the outer case, Wrinkles that occur near the boundary can be prevented, and the caulking force by the mold at the curved portion and the long side portion of the opening of the exterior case can be individually managed, so the curved portion and the long side portion Since it can be swaged by a molding die with a caulking force suitable for each bay, the sealing strength (adhesion) to the sealing member at the curved portion and the long side portion can be made uniform.

Of the curved portion and the long side portion of the outer case, the arc-shaped curved portion has a strength compared to the substantially straight long side portion, and the opening portion of the outer case extends sufficiently, so that the caulking process is performed. Since it is easy to perform, it is preferable to first crimp the curved portion of the exterior case to form the crimp on the curved portion, and then perform the crimping of the long side portion of the exterior case. By first crimping the curved portion of the exterior case, the strength of the entire exterior case is increased during the crimping process, that is, the crimping force during the crimping process because the crimping of the curved portion is substantially straight. Can be reinforced, and the long side can be easily and accurately swaged, so that the crimping wrinkles near the boundary between the curved portion and the long side of the exterior case The non-uniformity of sealing performance between the curved portion and the long side portion can be eliminated.

Moreover, even if the ratio of the short side to the long side of the outer case with an oval cross section is 1: 3 or more, that is, the long side of the outer case is relatively long, the sealing performance is accurate. An excellent sealing structure can be easily achieved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to examples shown in the drawings.

  1 to 5 show an embodiment of the present invention. FIG. 1 is a perspective view showing an electrolytic capacitor in an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a caulking process of a bending portion of the present invention, and FIG. 3 is a caulking portion of the present invention. FIG. 4 is a cross-sectional view showing the opening of the electrolytic capacitor, FIG. 4 is a cross-sectional view showing the caulking process of the long side portion of the present invention, and FIG. .

  In the embodiment of the present invention, as shown in FIG. 1, the outer case 2 is made of aluminum, or an aluminum alloy such as aluminum or manganese, the opposing long side 6 and the curved part 5 continuous to the long side 6. It consists of bottomed cylindrical shape formed in the ellipse provided with. That is, the exterior case 2 is formed of a pair of substantially straight long side portions 6 and a curved portion 5 that are parallel or substantially parallel to each other in a plane, and has an oval cross section. An overhanging portion 13 is formed on the side surface near the opening so as to be substantially parallel to the bottom surface of the metal case 4 in order to fix the sealing member 3. Instead of the projecting portion 13, an outer case provided with a lateral groove in the vicinity of the opening may be used for fixing the sealing member 3. The oval outer case 2 has a dimensional ratio of 1: 3 between the short side and the long side. The outer case 2 has a thickness of 0.35 mm.

  In the embodiment, the capacitor element 1 is formed by winding a bipolar electrode foil made of aluminum or the like through a separator. The sealing member 3 is made of a material having an elastic force such as rubber and capable of maintaining airtightness, a material in which an elastic rubber and a synthetic resin plate are laminated, and an elastic rubber or the like on the outer peripheral portion of the synthetic resin plate. The one with an O-ring fitted is used. Further, as the sealing member 3, a member in which a through hole penetrating the lead terminal 4 led out from the capacitor element 1 is formed in the vicinity of the center portion, or a member to which an external connection terminal is fixed is used.

  Then, as shown in FIG. 2, the sealing member 3 is inserted into the outer case 2 together with the capacitor element 1. The sealing member 3 is made of a material having an elastic force such as rubber and capable of maintaining airtightness, and its shape matches the opening shape of the outer case 2. In addition, in order to improve sealing performance, it is good also as a taper shape which made the insertion side to an exterior case narrow in the side surface of the sealing member 3, and made the exterior side wider than the opening shape of an exterior case. The sealing member 3 is formed with two through-holes for lead terminals in the vicinity of the central portion thereof, the lead terminal 4 drawn out from the capacitor element 1 is penetrated, and the lead terminal 4 is provided on the outer surface of the sealing member 3. Keep protruding.

  Thus, the exterior case 2 to which the sealing member 3 is mounted is fixedly held by the holding mold 12 so as to be fitted in the overhanging portion 13.

  Next, the first mold 7 is pressed from the direction of the arrow a, and a sealing process is performed as shown in FIG. As shown in FIG. 5, the first mold 7 performs caulking processing of the curved portion 5 continuous from a pair of opposed long side portions 6 in the opening of the outer case 2, and has a tapered surface. A first guide surface 9 is formed, a second guide surface 10 is formed continuously with the guide surface 9, and a molding surface 11 is formed continuously with the guide surface 10. In the center, a through hole 14 for letting the lead terminal 4 escape is formed. That is, the first guide surface 9 is larger than the opening shape of the outer case 2 and narrows as it goes upward, and the second guide surface 10 has a shape that matches the opening shape of the outer case 2. The molding surface 11 extends from the guide surface 10 and forms, for example, a curved surface in order to obtain a desired crimped shape in the outer case 2. FIG. 2 shows a cross-sectional shape before caulking of the curved portion 5 of the outer case 2 and cross-sectional shapes of the guide surfaces 9 and 10 and the molding surface 11 of the first mold 7 of the curved portion 5. When the curvature radius of the molding surface 11 is L / 2 and the depth D is (L / 2) ± α, α is corrected corresponding to the shape of the sealing member 3 and an optimum value is set. To do.

  When the first mold 7 for crimping the curved portion 5 of the outer case 2 is pressed against the opening of the outer case 2, the curved portion 5 of the outer case 2 is guided by the guide surfaces 9 and 10 to be the molding surface. 11 is bent along the shape of the molding surface 11 in accordance with the applied pressure, the bending portion 5 is crimped, and the bending portion 5 of the outer case 2 is formed as shown in FIG. At this time, the bend subjected to caulking is performed near the wavy line that is near the boundary between the curved portion 5 and the long side portion 6 of the exterior case 2 shown in FIG. A caulking part that gradually rises from the caulking position of the part 5 to the height position of the long side part 6 that is not yet caulked is formed.

In addition, when the molding surface of the first molding die 7 for caulking the curved portion 5 is pressed against the curved portion 5, the vicinity of the boundary between the curved portion 5 and the long side portion 6 is approximated. In order to make it easy to form the crimped portion, by providing an inclination in the vicinity of the boundary with the long side portion 6 of the molding die 7 from the molding surface toward the outside of the opening of the exterior case 2, A caulking portion in the vicinity of the boundary can be formed with high accuracy.

Next, as shown in FIG. 4, the long side portion 6 of the outer case 2 is crimped while the outer case 2 with the curved portion 5 crimped by the first mold 7 is fixedly held to the holding die 12. It is pressed from the direction of arrow b with the second mold to be performed, and the sealing process is performed again. The second mold for caulking the long side portion 6 is for caulking near the boundary between the long side portion 6 and the curved portion 5 and the long side portion 6, and is a first surface formed of a tapered surface. A guide surface 9 is formed, a second guide surface 10 is formed continuously with the guide surface 9, and a molding surface 11 is formed continuously with the guide surface 10. A through hole 14 for releasing the lead terminal 4 is formed. That is, the first guide surface 9 is larger than the opening shape of the outer case 2 and narrows as it goes upward, and the second guide surface 10 has a shape that matches the opening shape of the outer case 2. The molding surface 11 extends from the guide surface 10 and forms, for example, a curved surface in order to obtain a desired crimped shape in the outer case 2. FIG. 2 shows a cross-sectional shape before caulking of the curved portion 5 of the outer case 2 and cross-sectional shapes of the guide surfaces 9 and 10 and the molding surface 11 of the first mold 7 of the curved portion 5. When the curvature radius of the molding surface 11 is L / 2 and the depth D is (L / 2) ± α, α is corrected corresponding to the shape of the sealing member 3 and an optimum value is set. To do.

  When the second mold 8 for crimping the long side portion 6 of the outer case 2 is pressed against the opening of the outer case 2, the long side portion 6 of the outer case 2 is guided by the guide surfaces 9 and 10. Facing the molding surface 11, it curves along the shape of the molding surface 11 according to the applied pressure, the long side portion 6 is crimped, and the long side portion 6 of the exterior case 2 is molded. The entire circumference is crimped. When the curved portion 5 of the outer case 2 is crimped by the first mold 7, the length dimension of the second mold 8 for crimping the long side portion 6 is set to the length of the outer case 2. By setting the dimensions to include the long side portion 6 and the vicinity of the boundary, the crimped portion formed near the boundary between the curved portion 5 and the long side portion 6 is also crimped simultaneously, and the curved portion 5 and the long side The occurrence of caulking wrinkles generated by the difference in elongation during caulking with the portion 6 is absorbed by the caulking portion in the vicinity of the boundary formed in advance by the first mold 7 for caulking the bending portion 5. The occurrence of the crimping wrinkles is suppressed.

In addition, since the long side part 6 of the exterior case 2 is not easily extended during the caulking process, the caulking force is relatively strong as compared with the caulking process of the curved part 5 of the exterior case 2 in order to closely contact the sealing member 3. In this case, as shown in FIG. 1, the final shape of the outer case 2 being crimped is such that the long side portion 6 of the outer case 2 is strongly crimped compared to the curved portion 5, and the sealing member 3. It has a shape with a step between the curved portion 5 and the long side portion 6.

  As described above, since the caulking process of the curved portion 5 and the long side portion 6 of the opening of the outer case 2 is performed individually, the caulking that occurs near the boundary between the curved portion 5 and the long side portion 6 is performed. Since it can prevent tightening wrinkles, enhance the sealing performance, and can set the crimping force appropriately according to the tightness of the curved portion 5 and the long side portion 6 to the sealing member 3, respectively, The long side part 6 and the curved part 5 of the outer case 2 are sufficiently pressed against the sealing member 3 to achieve a sealing structure with excellent sealing performance.

  When the ratio of the short side to the long side of the oval outer case 2 is 1: 3 or more, the entire circumference of the opening of the outer case 2 as in the prior art is performed in one step with a mold. In the caulking method, there are problems that caulking wrinkles occur near the boundary between the curved portion 5 and the long side portion 6 of the outer case 2 or that the adhesion to the sealing member 3 is uneven. According to the invention, even if the ratio of the short side to the long side of the oval outer case 2 is 1: 3 or more, the crimping process of the curved portion 5 and the long side portion 6 of the outer case 2 is individually performed. Therefore, the non-uniformity of the adhesion to the caulking wrinkles and the sealing member 3 is reduced, and the thickness of the outer case 2 is reduced to 0 in order to increase the storage efficiency of the capacitor element 1 in the outer case 2. Even if it is thinned to 35 mm or less, such a thin outer case 2 is strong against caulking. Bur, excellent sealing structure of adhesion can be achieved. In addition, in order to increase the strength of the long side portion of the outer case 2, a groove, a rib, or the like may be provided near the opening of the long side portion of the outer case 2.

  In the embodiment, the outer case 2 to which the sealing member 3 is attached is fixedly held by the holding mold 12 so as to be fitted in the protruding portion 13 formed in the vicinity of the opening portion. By placing a caulking jig (holding die 12) on 13, the pressure applied during caulking can be concentrated on the opening of the outer case 2 and applied to other parts of the outer case 2. Unnecessary mechanical stress can be reduced.

  The present invention has been described with reference to the drawings. However, the present invention is not limited to these examples, and modifications and additions within the scope of the present invention are included in the present invention. Needless to say.

  For example, in the said Example, although what crimped the long side part 6 of the exterior case 2 after the crimping process of the curved part 5 of the exterior case 2 was shown, it is not restricted to this, After the long side portion 6 is swaged, the curved portion 5 may be swaged.

  Moreover, you may perform a preliminary | backup caulking process as a pre-process of the caulking process of the curved part of the said exterior case, or the caulking process of a long side part. This preliminary caulking process involves friction generated between the molding surface of the mold and the opening surface of the outer case by bending the curved portion or long side portion of the opening portion of the outer case in advance to a predetermined angle inside the outer case. The force is reduced, and the caulking process of the curved portion or the long side portion of the outer case, which is the main caulking step, can be easily and accurately performed. In particular, since the long side portion is difficult to extend during caulking, and is difficult to adhere to the sealing member, the effect of preliminary caulking at the long side portion is great. Moreover, the caulking process of the curved part of the outer case and the preliminary caulking process of the long side part of the outer case can be performed simultaneously, and the manufacturing process can be simplified.

Moreover, in the said Example, although what used the winding type capacitor | condenser element 1 formed by winding the bipolar electrode foil which consists of aluminum etc. through the separator was shown, not only this but bipolar electrode foil is used. A multilayer capacitor element formed by alternately laminating via separators may be used. In addition, as an element using an electrochemical element, the present invention may be applied to a sealing process of a capacitor using an electric double layer capacitor element in which a polarizable electrode mainly composed of activated carbon or the like is formed on a current collector.

The perspective view which shows the electrolytic capacitor in the Example of this invention. Sectional drawing which shows the caulking process of the curved part of this invention. Sectional drawing which shows the opening part of the electrolytic capacitor by which the curved part of this invention was crimped. Sectional drawing which shows the caulking process of the long side part of this invention. The figure which shows the exterior case of the cross sectional view ellipse of this invention. The partial perspective view which shows an oval electrolytic capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Exterior case 3 Sealing member 4 Lead terminal 5 Bending part 6 Long side part 7 1st shaping | molding die 8 2nd shaping | molding die 9 1st guide surface 10 2nd guide surface 11 Molding surface 12 Holding mold 13 Overhang part 14 Through hole

Claims (2)

The capacitor element is housed in a bottomed cylindrical outer case having an oblong cross section having a pair of opposed long side portions and a curved portion continuous with the long side portion, and a sealing member is inserted into the opening of the outer case, In the method of manufacturing an electrolytic capacitor in which caulking is performed on the entire periphery of the opening of the outer case, the long side or curved portion remaining as unclamped after the caulking of the curved portion or long side of the outer case is performed. Electrolytic capacitor manufacturing method that performs individual crimping process . 3. The method for manufacturing an electrolytic capacitor according to claim 1, wherein the outer case having an oval cross section has a dimensional ratio of a short side to a long side of 1: 3 or more.

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