JPS6036095B2 - Sealing method for electrolytic capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in electrolytic capacitors, and particularly to a method for sealing electrolytic capacitors using an exterior case made of synthetic resin.

When a capacitor element is housed in an outer case made of synthetic resin and the closing part of the outer case is sealed with an enclosure,
As shown in FIG. 1, a sealing body 3 was attached to the opening of the outer case, and an adhesive 4 was applied thereto.

Alternatively, as shown in Fig. 2, it has been considered to fill the upper part of the insulating plate 5 in the closed part of the exterior case with thermosetting synthetic resin 6 or photocuring synthetic resin 6 to seal it. . Alternatively, a sealing body made of synthetic resin is attached to the closed part of an exterior case made of synthetic resin, and the seal is sealed by ultrasonic melting.

However, when using an adhesive 4 as shown in FIG. 1, or when sealing with a heat or photo-curable synthetic resin 6 as shown in FIG. It is necessary to harden the adhesive 4, etc., which is complicated, and the adhesive 4 or the synthetic resin 6 may cause corrosion.

Furthermore, if the adhesive 4, synthetic resin 6, etc. are not uniformly applied to the entirety of the sealing body 3, minute gaps may occur, making it difficult to maintain airtightness. Further, even when the outer case and the sealing body are sealed by ultrasonic welding, minute gaps, so-called pinholes, may occur depending on the ultrasonic welding conditions.

An object of the present invention is to provide a sealing method that maintains airtightness by attaching a sealing body made of elastic rubber to an exterior case made of synthetic resin.

This invention involves the steps of storing a capacitor element in a bottomed cylindrical outer case made of synthetic resin, attaching a disc-shaped sealing body made of elastic rubber to the entrance of the outer case, and storing the capacitor element. In the opening □ of the exterior case,
At the same time, an ultrasonic welding horn with an arcuate end face is applied to the exterior case, and a predetermined pressure is applied to the exterior case.
It consists of a step of folding back the closed part of the outer case inward by applying ultrasonic waves, and is characterized in that the folded part of the outer case is combed and inserted into the sealing body.

Embodiments of the present invention will be described below with reference to the drawings. The capacitor element 2 is formed by winding electrode foil and electrolytic paper.

As shown in FIG. 3, this capacitor element 2 is housed in a bottomed cylindrical outer case 1 made of synthetic resin. Next, a disc-shaped sealing body 8 made of elastic rubber is attached to the open end of the outer case. This sealing body 8 has an outer diameter dimension that is slightly larger than the inner lining dimension of the outer case 1. Note that the lead 7 led from the capacitor element 2 penetrates the sealing body 8 and projects to the outside. Next, on the end surface of the closed part of the outer case 1 in which the capacitor element 2 is housed and the enclosure 8 is attached, as shown in FIG.
A horn 10 for ultrasonic welding is brought into contact.

The inner diameter dimension of this horn 10 for ultrasonic waves is the outer case 1
The outer diameter is approximately the same as, or slightly larger than, the outer diameter, and an arcuate recess 9 is formed on the end surface. Ultrasonic waves are applied from this ultrasonic welding horn 10 to the end face of the exterior case, and at the same time, a predetermined pressure is applied to soften the closed end of the exterior case 1, so that a uniform arc-shaped fold is formed at the same time. Form. As described above, the open end of the electrolytic capacitor obtained according to the embodiment of the present invention is applied with ultrasonic waves and is pressed to form an arcuate fold.

When the open end of the outer case is folded back, as shown in FIG. 5, uniform pressure is applied around the sealing body 8 made of elastic rubber to maintain the airtightness of the outer case. In addition, as shown in Figure 6, the opening inside the outer case
A stepped portion may be formed near the portion to lock the sealing body 8.

In this case, the close contact between the envelope 8 and the folded part of the outer case is increased, so that high airtightness can be obtained. As described above, the present invention includes a process of housing a capacitor element in a bottomed cylindrical outer case made of synthetic resin, and a process of attaching a disc-shaped sealing body made of elastic rubber to the opening of the outer case. Then, an ultrasonic welding horn with an arc-shaped end face is applied to the entrance of the exterior case that houses the capacitor element, and a predetermined pressure is applied to the exterior case, and at the same time, ultrasonic waves are applied. This method comprises the steps of folding back the entrance part of the outer case to the inner surface, and combing the folded part of the outer case into the sealing body and inserting the folded part into the sealing body. Compared to the above, there are no minute gaps such as pinholes, and highly reliable airtightness can be maintained.

Furthermore, since no adhesive or the like is used, there is no risk of corrosion caused by the adhesive or the like. Furthermore, the fold formed at the open □ end of the exterior case is integrally formed by an ultrasonic welding horn having an arc-shaped end surface, so that it forms a substantially uniform arc.

Therefore, this folded back can be combed and tucked into the sealing body made of elastic rubber with uniform pressure, thereby reliably sealing the inside of the outer case. Further, the folding of the open end of the outer case is formed by applying ultrasonic waves and a predetermined pressure at the same time using an ultrasonic welding horn having an arcuate end surface. Therefore, it becomes easy to simplify and speed up the manufacturing process. Furthermore, in the sealing method according to the present invention, the sealing body made of elastic rubber used in ordinary electrolytic capacitors can be used as is.

As described above, this invention is a useful invention that realizes reliable sealing between the outer case made of synthetic resin and the sealing body made of elastic rubber.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing the structure of an electrolytic capacitor using a conventional sealing method, FIGS. 3 to 5 are partial cross-sectional views explaining the sealing method of the present invention, and FIG. ,b
FIG. 2 is a sectional view showing another embodiment of the invention. 1...Exterior case, 2...Capacitor element, 3, 8...
...Sealing body, 4...Adhesive, 5...Insulating board, 6
...Synthetic resin, 7...Lead, 9...Recess, 10...Horn. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] 1. A step of storing a capacitor element in a bottomed cylindrical outer case made of synthetic resin, a step of attaching a disc-shaped sealing body made of elastic rubber to the opening of this outer case, and a step of storing the capacitor element in the outer case. An ultrasonic welding horn with an arcuate end face is brought into contact with the opening of the
An electrolytic capacitor comprising the steps of applying a predetermined pressure to the outer case and simultaneously applying ultrasonic waves to fold back the opening of the outer case inward, the folded part of the outer case being embedded in the sealing member. The method of sealing.