JPS5952826A - Condenser with pressure type protecting device - 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] Industrial applications The present invention relates to a pressure protection capacitor.

Conventional configurations and their problems There are many types of pressure protection devices, but the pressure of the gas generated when a capacitor ruptures
c9. The expansion of the bellows-like case or the deformation of the lid is used to tear off the lead wire or disconnect the contact portion. At this time, please note that
One end of the lead wire is fixed. For example, when a bellows-like case is used, one end of the lead wire is soldered to the capacitor element, so the capacitor element must be fixed. For this purpose, a bellows-like case is provided with a neck for fixing the element, and the capacitor element is fixed to the bellows-like case via an insulating inner case. Furthermore, when the deformation of the lid is utilized, one lead wire is fixed to a member that does not deform.

Conventional pressure protection devices were developed based on the premise of using solid wax as an impregnating agent, and methods that utilize the deformation of the lid have also been developed using bellows, which can reduce the number of parts. Even with a method using a similar case, an extra inner case was required to secure the capacitor element.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the need for an inner case for fixing the capacitor element, considering the use of a solid resin as a sealant.

Structure of the Invention In order to achieve this object, the present invention accommodates a capacitor element in an inner case made of plastic, houses the inner case in a metal case, and uses a sealing resin inside the inner case. The inner case, which connects the inner case to the external sealing resin, has a shape that makes it impossible to pull out both the inner and outer surfaces of the inner case.

DESCRIPTION OF EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 shows a sectional view of an embodiment of a pressure protection device-equipped capacitor according to the present invention. That is, a capacitor element 1 is housed in an inner case 2 made of plastic, and this inner case 2 is housed in a metal case 3 with bellows, and a sealing resin 4 is connected to the inside of the inner case 2. Meet the outside. Furthermore, the sealing resin 4 inside the inner case 2 and the sealing resin 4 outside the inner case 2 are connected at the upper part of the inner case 2 in this example. The main feature of this embodiment is the connection of the sealing resin 4. If the inner case 2 is made of a polyolefin resin, such as a resin containing polypropylene or polyethylene, or if it is made of other plastic but has a mold release agent on its surface during molding, the inner case 2 and the sealing resin 4
If the adhesion between the inner case 2 and the sealing resin 4 is weak and there is no connection between the sealing resin 4 inside and outside the inner case 2, the capacitor element 1 will break and gas will be generated. The case 2 and the sealing resin 4 separate, and the capacitor element 1 is pulled by the bellows and rises, making it impossible to tear off the notch of the lead wire. In contrast, as shown in FIG. 1, the sealing resin 4 on the top of the capacitor element 1 adheres to the metal case 3 and serves to fix the capacitor element 1.

FIG. 2 is a diagram showing another embodiment according to the invention. In this configuration, in the upper part, the sealing resin 4 inside and outside the inner case 2 is
Although there is no connection, there is a hole 6 in the lower part of the inner case 2, which connects the sealing resin 4 inside and outside the inner case 2. This makes it possible to fix the capacitor element 1 against expansion of the bellows.

FIG. 3 shows a sectional view of another embodiment according to the invention. That is, a capacitor element 1 is housed in an inner case 2 made of plastic, and this inner case 2 is housed in a metal case 3 with bellows, and a sealing resin 4 connects the inside and outside of the inner case 2. Satisfied. A feature of the non-embodiment is that the inner case 2 has a shape with the opening side tapered on both the inner and outer surfaces. By this f, even if the inner sealing resin and the outer sealing resin of the inner case 2 are not connected as shown in FIGS. 1 and 2, the interface between the inner case 2 and the sealing resin 4 can be This prevents the capacitor element 1 from being pulled out by peeling off.

FIG. 4 also shows an embodiment using an inner case 2 having a shape that cannot be pulled out. In this case, the lower part of the inner case 2 is enclosed. If such grooves and dents are provided somewhere on the inner case 2, even if the interface between the sealing resin 4 and the inner case 2 separates, the capacitor element 1 will not move as the bellows stretches. It can be prevented. By attaching a neck fL6f to the metal case 3, the capacitor element 1 can be fixed even if the duck case 3 and the sealing resin 4 should peel off, increasing the reliability of the protection device. It's high.

Injection molding, blow molding, etc. can be used to process the inner case 2, but if the shape is as shown in FIG. It is also possible to As the sealing resin, epoxy resin, urethane resin, polyester resin, etc., which have good adhesion to the metal case and have a certain strength, can be used.

Specific examples are shown below.

Example 1 A metalized film capacitor was used as a capacitor element by winding a pair of metalized polypropylene films with a thickness of 6 μm with aluminum vapor-deposited on one side so that the sheet resistance was 3.5 Ω/hole, and then thermally spraying zinc on the end surfaces. First, it was housed in an inner case made by injection molding polypropylene resin, and then this inner case was housed in a metal case made of aluminum. After this, a two-component epoxy resin was injected and cured. The shape of the inner case shown in Fig. 1 and that shown in Fig. 2 are used.For the shape shown in Fig. 1, the one in which the sealing resin inside and outside of the inner case is not connected is used for comparison. Created as. After the sealing resin has hardened,
A bellows was machined on the upper part of the metal case, the lid assembly was placed on top, the lead wires were soldered, and then the lid and the metal case were sealed together by curling.

Example 2 The same capacitor element as in Example 1 was used, and a filler-containing polypropylene resin was housed in an inner case injection-molded in the same shape as shown in Figure 1, and then the inner case was molded in the same shape as shown in Figure 3. Close the opening by heating! After that, it was placed in a metal case.

Thereafter, a final shape 1 was manufactured in the same manner as in Example 1.

Example 3 The same capacitor element as in Example 1 was used, the inner case was made of polypropylene resin with an edge formed by blow molding in the same shape as shown in Fig. 4, and the sealing resin for the case was a filler-containing resin. Using a two-component epoxy resin,
The final shape trench was manufactured using the same procedure as in Example 1.

The capacitors with pressure protection devices manufactured in Examples 1 to 3 were destroyed by applying an alternating current voltage in a constant temperature bath at 100°C. The uninvented sealing resin inside and outside the inner case is connected.
Or, in a capacitor with a pressure protection device that uses a non-removable inner case, even if the breakage occurs, the bellows will stretch only if the lead wire is pulled and the bellows stretches. In contrast, in a capacitor made for comparison in which the sealing resin inside and outside of the inner case was not connected and had a removable inner case, the lid broke at the same time. Mistakes occur frequently. The results of the disassembly show that there was separation between the inner case and the sealing resin on the surface of the inner case, and that the capacitor element was pulled out from the metal case due to the elongation of the bellows immediately after the breakage. It was observed that only one lead wire had been cut off, but since the lid was not part of the metal case, the degree of destruction was severe. Rather than the opening of the inner case being buried in the sealing resin as shown in Figure 1, the opening of the inner case protrudes from the sealing resin as shown in Figures 2 to 4. It is better to do so because this protruding part helps insulate the metal case from the lead wire, which is more flexible, so that it does not break when the capacitor breaks down.

As a result of the invention, a condenser with a pressure protection device that has a small number of parts and is highly reliable can be provided by using non-inventive techniques as described in 2 above, and its industrial efficiency is excellent.

[Brief explanation of drawings]

1 to 4 are cross-sectional views of embodiments of a capacitor with a pressure protection device according to the invention. 1... Capacitor element, 2... Inner case, 3... Metal case, 4... Sealing resin, 5... Hole , 6... neck fL. Name of agent: Patent attorney Toshio Nakao and 1 other person 1J
S1 Figure 2 @ Figure 3

Claims (1)

[Claims] The capacitor element is housed in an inner case made of plastic, and the inner case is housed in a metal case, and a sealing resin inside the inner case and a sealing resin outside the inner case are connected to each other. 1. A capacitor with a pressure protection device, characterized in that the inner case is connected to each other or has a shape that makes it impossible to pull out both the inner and outer surfaces of the inner case.