JPS6326533B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrolytic capacitor with an improved sealing part.

In a conventional electrolytic capacitor, as shown in FIG. Closed and sealed.

That is, since the elastic body 3 such as rubber is used to seal the opening of the case 1, the elastic body hardens during a long-term life test in a high-temperature atmosphere, and the airtightness deteriorates, causing leakage of the electrolyte. There were drawbacks such as deterioration of characteristics. Furthermore, when cleaning with a solvent etc. after soldering to a printed circuit board, some capacitors have a resin such as epoxy applied to the sealing part and hardened to protect it, in order to prevent the cleaning liquid from penetrating into the inside of the capacitor. However, the disadvantage was that the unit cost of parts and materials as well as the number of manufacturing steps increased, making the product expensive.

The present invention aims to eliminate the above-mentioned drawbacks and provide an electrolytic capacitor that can withstand high temperatures and is highly reliable.

The present invention will be described below with reference to the embodiments shown in FIGS. 2 and 3.

Figure 2 A, B are cross-sectional views of electrolytic capacitors, C,
D is a cross-sectional view of the case, and the case 7 is made of cylindrical aluminum or thermoplastic resin, and a thin wall portion 7b is provided at a position less than 1/2 of the diameter of the case 7 from the open end, and the capacitor element 8 is housed therein. After that,
The opening end 7a of the case 7 is bent at the thin part 7b to cover the sealing part through a resin sheet 5 such as polypropylene, and the bent part is filled with resin 6. When the case 7 is made of thermoplastic resin, it is preferable to preheat it in advance and bend the end portion 7a. Further, the filling resin is preferably one such as acrylic, phenol, epoxy, or urethane, which polymerizes and hardens in a short time. 9 is a lead wire led out from the capacitor element 8.

Note that the resin sheet 5 may be an elastic body.

Figure 3 is a plan view of the electrolytic capacitor, case 7.
An example is shown in which the opening end 7a is modified, in which (a) the part from the thin wall part 7b to the opening end is formed into a tongue shape and the shape is trapezoidal, (b) a fan-shaped one,
Ha is round.

The electrolytic capacitor of the present invention is manufactured as described above.

Therefore, since the case 7 is provided with the thin wall portion 7b, the open end 7a of the case 7 can be easily bent. When voltage is applied to the capacitor, under normal conditions, the bent part of the case 7 protects the fixation of the resin 6, resulting in a marked increase in airtightness, and the sealing body will not deteriorate even if used for a long time in a high temperature atmosphere. Therefore, leakage of electrolyte and deterioration of characteristics hardly occur. On the other hand, when an abnormal voltage or a reverse voltage is applied to the capacitor and the internal pressure of the capacitor increases, the thin wall portion 7b is provided at the bent portion of the open end 7a.
As a result of being pushed outward by the resin 6, gas can be released and an explosion-proof function can be achieved. Furthermore, since the lead wire 9 is fixed to the case 7 by the resin 6, many effects can be obtained, such as being able to prevent the generation of electrical noise even in response to physical impact.

Note that the above embodiment has a cylindrical shape and has open ends 7 at both ends.
Although the case 7 has been described with
b may be formed continuously or intermittently on the inner or outer surface of the case 7. The bending angle of the opening end 7a is not limited to a right angle, but may be any angle as long as it covers the sealing part.

As described above, the present invention can provide an electrolytic capacitor with significantly improved airtightness and high reliability, and is of great practical value.

[Brief explanation of the drawing]

Figures 1A and 1B are cross-sectional views of conventional electrolytic capacitors, and Figures 2 and 3 are embodiments of the present invention.
A and B are cross-sectional views of the electrolytic capacitor, C and D are cross-sectional views of the case of the electrolytic capacitor, and FIG. 3 A, B and C are plan views of the electrolytic capacitor. 6: Resin, 7: Cylindrical case, 7a: Open end, 7b: Thin wall portion, 8: Capacitor element.

Claims (1)

[Claims] 1 A thin-walled part is provided at a position less than 1/2 the diameter of the case from the open end of a cylindrical bottomed or bottomless case, and the part from the thin-walled part to the open end is formed into a tongue shape, and the above-mentioned case A capacitor element is housed in the capacitor element, a resin sheet is disposed between the capacitor element and the open end of the case, and the thin wall part is configured to bend the open end of the case to cover the sealing part. An electrolytic capacitor characterized by having its parts filled with resin.