JPH04355908A - Sealing method for electrolytic capacitor - Google Patents

Abstract

PURPOSE:To obtain the sealing method for electrolytic capacitor having a highly reliable sealing state by caulking a sheathing case consisting of a flat part having oblong cross-section and a curved portion in an easy but accurate manner. CONSTITUTION:A capacitor element 2 is housed using a sheathing case 4 provided with flat plates 41 which are positioned in parallel with each other or almost in parallel with each other, and curbed parts 42 which are continuous to the flat plates. The title electrolytic capacitor sealing method is the method in which a caulking work is conducted on the edge part of the sheathing case, provided on the above-mentioned sealing member, toward the upper surface side of the sealing member after the sealing member 6 has been inserted into the aperture part of the sheathing case. After a notched part 11 has been formed on the part ranging from the flat section of the aperture part of the sheathing case to the curbed section of the aperture part, a caulking work in performed on the above-mentioned sheathing case.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of sealing an electrolytic capacitor using an outer case having an oval cross section.

0002

2. Description of the Related Art Hitherto, flat electrolytic capacitors have been used, and as shown in FIG. A sealing member 6 is inserted together with the capacitor element 2 into a metallic exterior case 4 formed to match the shape of the capacitor element 2, and the opening thereof is sealed. A through hole 10 is formed in the sealing member 6 to allow a rod-shaped lead 8 pulled out from the end surface of the capacitor element 2 to pass through and hold it. The sealing member 6 is fixed to the end surface of the capacitor element 2 by passing the lead 8 through the end surface of the capacitor element 2 prior to sealing the outer case 4 . For example, ideally, the opening of the exterior case 4 should be sealed by crimping, as shown in FIG.

0003

[Problems to be Solved by the Invention] By the way, when crimping the exterior case 4 that is not a perfect circle, that is, has a flat plate part and a curved part, the radius of curvature of the flat plate part and the curved part naturally differs. Because of this difference, even if a rotary molded body is pressed and molding pressure is applied, it is impossible to apply molding force evenly due to its shape, and a molded state for obtaining the necessary airtightness cannot be obtained.

[0004] Furthermore, if the crimping force is applied based on the part where the forming force is not sufficiently applied, the crimping will be excessive in the part where stress concentration occurs, and the sealing strength will be impaired due to the distortion caused by the formation. There is a risk of reducing airtightness.

[0005] For this reason, the sealing of such an exterior case 4 has a guide surface that matches the opening edge of the exterior case 4 that is formed into a non-perfect circle, and this guide surface is extended to curve inward. We have filed an application for a sealing method that achieves reliable sealing using a mold with a molded surface.

Accordingly, the present invention provides a method for sealing an electrolytic capacitor that more easily and reliably crimps an outer case consisting of a flat plate portion such as an oval cross section and a curved portion, and achieves a highly reliable sealing state. The purpose is to provide

[0007]

[Means for Solving the Problems] A method for sealing an electrolytic capacitor according to the present invention provides a method for sealing an electrolytic capacitor in which parallel or nearly parallel opposing flat plate portions (
The capacitor element (2) is housed using an exterior case (4) having a curved portion (41) and a curved portion (42) continuous to the flat plate portion, and a sealing member (6) is placed in the opening of the exterior case. A method for sealing an electrolytic capacitor in which the edge of the outer case protruding above the sealing member is crimped toward the upper surface of the sealing member after inserting the sealing member, the method comprising:
The present invention is characterized in that after a notch (11) is formed in a portion of the opening of the exterior case from the flat plate portion to the curved portion, the caulking process is performed on the exterior case.

[0008]

[Operation] Since a notch is formed in the opening of the exterior case 4 from the flat plate part to the curved part, crimping stress concentrates on the notch, and crimping proceeds from that part to form the entire body. As a result, the crimping process is easily performed, uniform molding is performed, and the outer case 4 is sealed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the method for sealing an electrolytic capacitor according to the present invention. As shown in FIG. 1A, the outer case 4 is formed from metal such as aluminum to have an oval cross section. That is, the exterior case 4 is formed from a pair of flat plate portions 41 and a curved portion 42, each of which has a flat plate shape and has opposing parallel or nearly parallel wall surfaces, and has an oval cross section. V-shaped notches 11 are formed in the opening of the exterior case 4 at four locations from the flat plate part 41 forming the flat plate-like opposing parallel wall surfaces to the curved part 42, that is, in the part with less curvature. Form. This notch 11 is formed at the same time as or after forming the outer case 4 into a cylindrical shape.

[0010]The outer case 4 is shown in FIG. 1(B).
As shown in FIG. 2, the sealing member 6 is inserted together with the capacitor element 2. The sealing member 6 is made of a material such as rubber that has elasticity and can maintain airtightness, and its shape is made to match the shape of the opening of the outer case 4. and,
Two through holes 10 for terminals are formed in advance in this sealing member 6, through which leads 8 drawn out from the capacitor element 2 are passed, and the leads 8 are made to protrude from the outer surface of the sealing member 6. put.

The outer case 4 with the sealing member 6 mounted in this manner is fixedly held by the holding mold 12, and in this case, the open end of the outer case 4 is made to protrude from the upper part of the holding mold 12.

Next, as shown in FIG. 1B, a mold 14 is pressed from above the outer case 4 in the direction of arrow a to perform a sealing process. The mold 14 has a first guide surface 16 formed of a tapered surface, a second guide surface 18 continuous to this guide surface 16, and a second guide surface 18 continuous to this guide surface 18. A molding surface 20 is formed, and a through hole 22 for allowing the lead 8 to escape is formed in the center thereof. That is, the first guide surface 16 is larger than the opening shape of the outer case 4 and narrows upward, and the second guide surface 18 has a shape that matches the opening shape of the outer case 4. The molding surface 20 is the guide surface 1
8 and forms a curved surface, for example, in order to obtain a desired crimp shape for the exterior case 4. FIG. 2 shows the planar shape of the guide surfaces 16, 18 and molding surface 20 of the mold 14. Note that the radius of curvature of the molding surface 20 is L/2,
If the depth D is (L/2) ±α, α is the sealing member 6
The optimum value shall be set by correcting it according to the shape of .

When such a mold 14 is pressed against the opening of the outer case 4, the opening of the outer case 4 faces the molding surface 20 guided by the guide surfaces 16 and 18, and the molding surface 20 is pressed against the molding surface 20 according to the pressing force. It is curved along the shape, and the opening is crimped to form the opening of the exterior case 4, as shown in FIG. 1C. In that case, the opening of the exterior case 4 has notches 11 formed at four locations from the flat plate part 41 to the curved part 42, that is, the part with small curvature, so the notches 11 are crimped. Stress concentrates and crimping progresses from that area and spreads to the whole area, so crimping is easily performed and a non-perfect round outer case 4 is formed, as shown in FIG. 1(C). Molding surface 20 of mold 14
It is evenly molded and sealed. As a result, Figure 3
As shown in FIG. 2, an electrolytic capacitor having a sealing portion shaped along the molding surface of the mold 14 is obtained.

[0014] When the notch 11 is provided in the opening of the outer case 4 and crimping is performed, when the mold 14 is pressed, the flat plate part 41 and the curved part 42 of the oval outer case 4 are separated. This compensates for the stress difference during compositional processing and facilitates molding, making it possible to prevent deformation of the exterior case 4 due to crimping.

[0015] In the embodiment, an elliptical outer case is shown as a non-perfect round outer case, but the present invention can also be applied to an outer case having a rectangular or polygonal shape and having a flat plate portion and a curved portion. can be applied.

[0016]

As explained above, according to the present invention, a notch is formed in the opening of an exterior case having a flat plate part and a curved part on the wall surface, and a cutout part is formed in the part extending from the flat plate part to the curved part. Because the tightening process is performed, it is possible to easily and reliably perform uniform crimping without deforming the outer case or applying unnecessary stress to the outer case due to deformation, and it also provides a highly reliable sealing condition. can be realized.

[Brief explanation of the drawing]

1 shows an embodiment of the electrolytic capacitor sealing method of the present invention, (A) is a perspective view showing the outer case, (B) is a sectional view of the outer case before crimping, and (C) is the outer case. FIG. 3 is a cross-sectional view after crimping.

FIG. 2 is a plan view showing a molding surface of a mold used in the method for sealing the electrolytic capacitor shown in FIG. 1;

FIG. 3 is a sectional view showing an opening of a sealed electrolytic capacitor.

FIG. 4 is a perspective view showing the configuration of a flat electrolytic capacitor.

5 is a partial perspective view showing a sealing portion of the electrolytic capacitor shown in FIG. 4. FIG.

[Explanation of symbols]

2... Capacitor element 4...Exterior case 6... Sealing member 11... Notch 41... Flat plate part 42...Curved part

Claims (1)

[Claims] 1. A capacitor element is housed using an exterior case comprising parallel or nearly parallel opposing flat plate portions and a curved portion continuous to the flat plate portion, and a sealing member is provided in the opening of the exterior case. A method for sealing an electrolytic capacitor in which the edge of the outer case protruding above the sealing member is crimped toward the upper surface of the sealing member after the outer case is inserted, the opening of the outer case A method for sealing an electrolytic capacitor, comprising: forming a notch in a portion extending from the flat plate portion to the curved portion, and then performing the caulking process on the outer case.