JPS60198806A - Method of producing capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a capacitor mainly used in communication equipment.

Conventional Structure and Problems Conventional resin-cast capacitors mainly use a plastic molded case, and are manufactured by placing a capacitor element in the case, injecting liquid resin, and hardening it. To explain the capacitor using drawings, in FIGS. 1 and 2, 1 is a plastic molded case, 2 is a part formed on the inner wall surface, and 4 is a space between the case 1 and the capacitor element 3. , 4 are resins that were cured after being injected into Case 1. Note that 6 is a fitting groove for the lead wire of the capacitor element 3 formed on the inner wall of the case 1.

This type of capacitor has a protrusion 2 on the inner wall of the case 1, so the case 1. Only when the capacitor element 3 has an ideal dimensional relationship, the tip of the protrusion 2 and the capacitor element 3
It is possible to hold the outer surface of the capacitor in contact and harden it by casting, but in practical terms, the rating of the capacitor varies in a complex manner, and the dimensions of the element also vary. Therefore, it is difficult to change the case dimensions or the protrusion dimensions in response to changes in the dimensions of these elements due to the need for molding molds or costs. For this reason, in terms of operation, it is generally adopted to use cases with the same size for capacitors with a certain range of ratings. The element is held in the center of the case by bending the lead terminal.
A method has been adopted in which the material is guided into a molded groove formed on the inner wall of the case and its elasticity is utilized. Therefore, in the conventional method,
The fact that the four parts and the convex part exist at the same time inside the case is important, and the two main points of exterior function, moisture resistance and element retention, depend on the short dimension from the element surface. At the same time, it is inefficient, and because the fixing method using lead wire terminals is a hanging method, it is difficult to accurately maintain the distance between the case inner wall and the element at all locations, and if the elements are unevenly distributed, the resin thickness will change, making it difficult to achieve the desired design. There was a drawback that it was impossible to maintain the dimensions.

Purpose of the Invention The present invention eliminates such conventional drawbacks and provides an efficient (☆
1. Structure of the invention to provide a fat-cast type capacitor Another structure of the present invention is to provide a protrusion made of ultraviolet curing resin on the outer surface of a capacitor element, and to connect the tip of the protrusion to the inside of the case. Inject the liquid resin while keeping the wall in contact with the
It hardens.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below. First, apply acrylic urethane to the outer surface of the capacitor element.

A UV-curable resin with high thixotropy such as acrylic epoxy or acrylic ester is deposited as a fixed amount of drip using a dispenser or special pipette, and the UV is applied to the resin drop before it flows and deforms due to gravity or other factors. It is irradiated to harden to a certain size (especially the height of the drip tip).

In this way, a capacitor element having resin protrusions is produced.

On the other hand, the case is made by molding various types of plastics, but it is a simple case with a uniform thickness and no protrusions or four parts on the inner wall. The inner dimensions may be better than the exterior dimensions. Next, by inserting the element produced as described above into the case, the element can be fixed within the case. At this time, the above-mentioned protrusion dimensions are determined in consideration of the case dimensions and the element dimensions. The size of this protrusion is determined depending on the amount of discharge from a dispenser or a special pipette, the time from the discharge of the thixotropic 7 drops of the ultraviolet curable resin to its curing, etc.

The above plastic case materials include polyethylene terephthalate, polybutylene terephthalate, polyvinyl chloride, ABS resin, polycarbonate, etc.
These are used after being subjected to ten-processing treatment or flame retardant treatment. Liquid resins to be cast include epoxy resins, polyester resins, urethane resins, and the like.

The capacitor manufactured as described above is illustrated as follows.
The result will be as shown in Figures 3 and 4. In the figure, 6 is a case with no protrusions or grooves on its inner wall surface, 7 is a capacitor element whose outer surface has a protrusion 8 made of ultraviolet curing resin, and 9 is a space between the case 6 and the capacitor element 7. , 9A is case 6
This is a resin that is cured after being injected into the interior.

Next, specific examples will be described. Two types of capacitor elements were manufactured: one in which a capacitor element was inserted into a conventional case, and one in which a capacitor element of the present invention, which was created under the same conditions as the above capacitor element, was inserted into a case. At this time, the external dimensions of both cases were kept constant, and after conducting a moisture resistance test for strong i1i purposes, the case thickness of the conventional case other than the protrusions and recesses was made the same as the case thickness of the product of the present invention, The results of the forced humidity test were conducted at 80°C and 984RH for 500 hours. Acrylic urethane, acrylic epoxy, and other types of UV-curable resins were used, but the results were the same.

Effects of the Invention As is clear from the above embodiments, according to the present invention, a capacitor with superior moisture resistance compared to conventional capacitors can be obtained. In addition, in contrast to conventional capacitors, in which the exterior phase material is used inefficiently from the point of view of fixing the element, the present invention has a shape in which a resin layer and case material are attached to the element surface at a constant thickness, and the exterior material is Uses less and maintains efficient exterior dimensions. The thickness of the case and the amount of resin used can be freely determined by considering cost, capacitor characteristics, and material processability.
It has many advantages such as the simple shape of the mold when molding the case, allowing various molding methods to be used.

[Brief explanation of drawings]

Figure 1 is a plan view of a conventional capacitor before injection of casting resin.
Figure 2 shows A- in Figure 1 after pouring the casting resin into the same capacitor.
3 is a plan view of the capacitor according to the present invention before injection of casting resin, and FIG. 4 is a sectional view taken along line A--A of FIG. 3 after injection of casting resin of the same capacitor. 6...Case, 7...Capacitor element, 8...Protrusion, 9...Space, 9A...
····resin. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure δ Figure 4 1 Tsumugi ■ 8

Claims (1)

[Claims] A method for manufacturing a capacitor, which comprises: providing a protrusion with an ultraviolet curing resin on the outer surface of a capacitor element, and holding the tip of the protrusion in contact with the inner wall surface of a case, injecting liquid resin, and curing.