JPS6384108A - Safety device of capacitor - Google Patents

Abstract

(57) [Abstract] 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 capacitor safety device.

2. Description of the Related Art In recent years, safety devices for capacitors that use thermoplastic resin as the exterior material and disconnect the electrical circuit by deforming the top lid have come into practical use (for example, Japanese Patent Application No. 8017-1982).
No. 7).

A conventional safety device will be explained below.

FIG. 6 is a sectional view of a conventional capacitor, in which 1 is a case made of thermoplastic resin, 2 is a top cover made of thermoplastic resin, and 3 is a capacitor element.

The upper lid 2 is formed into a dish shape, and includes a flat central portion 4 to which a plurality of metal terminals 7 are fixed, a tapered portion 5 around the flat central portion 4, and a tapered portion 5 around the central portion 4.
and a fitting part 6 with the case. 8 is a lead wire, which is connected to the terminal 7 via the weak point 1o provided on the support plate 9.
is connected to.

The operation of the security device configured as described above will be explained below. First, when the capacitor element 3 becomes abnormal, the internal pressure increases. At this time, as shown in FIG. 7, the upper lid 2 deforms in response to the pressure, and the weak point 1Q is cut off.

Problems to be Solved by the Invention However, in the conventional configuration described above, the tapered portion 5 responsible for deforming the upper lid 2 is provided in a narrow portion between the central portion 4 and the fitting portion 6. The center portion 4 usually requires an area of about 25φ in order to fix a plurality of terminals. Therefore, as the diameter of the case becomes smaller as capacitors become smaller and larger in capacity, the area of the tapered portion 50 inevitably becomes smaller, making it difficult to ensure sufficient operability of the safety device. It had

Means to Solve the Problems As a means to solve the above-mentioned conventional problems, the capacitor safety device of the present invention consists of a bottom central part of the case to which the winding core is fixed, and a thermoplastic resin. It consists of a bottom tapered part that protrudes inward of the case and protrudes outward when the internal pressure rises, and the lead wire is provided with a weak point that breaks when the internal pressure rises.

Effect With the above configuration, even in a small-diameter capacitor, the deformation portion can be provided over a wider area than in the conventional example, and sufficient operability of the safety device can be ensured.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

1 and 2 are cross-sectional views of a capacitor safety device according to a first embodiment of the present invention. In the figure, 11 is a case made of thermoplastic resin, and 12 is an upper lid. Reference numeral 14 denotes a winding core of the capacitor element 13, which is made of resin.
It is fixed with adhesive. 16 is a tapered portion provided on the bottom surface of the case. Reference numeral 17 denotes a lead terminal, which is connected to the capacitor element 13 via a weak point 18 and a lead wire 19.

The operation of the capacitor safety device configured as described above will be described below.

First, when the capacitor element 13 becomes abnormal, the internal pressure increases and the bottom surface of the case deforms. At this time, as shown in FIG. 2, the weak point 18 is cut and the electrical path is interrupted.

Table 1 shows the results of the operation test of the capacitor safety device having the configuration shown in FIG. 2 capacitors of various diameters
0 pieces were prepared, and a voltage twice the rated voltage was continuously applied at 20°C to cause forced destruction. For comparison, a similar test was also conducted on a conventional capacitor safety device having the configuration shown in FIG. The core diameter of the capacitor used in the present invention is 10φ, and the center part of the bottom of the case (
Figure 1-16) had a diameter of 13φ. The center part of the upper cover (FIG. 6-4) in the conventional capacitor was 25φ.

Table 1 Clearly, the capacitor safety device according to the present invention is more reliable than the conventional example.

As described above, according to this embodiment, the winding core of the capacitor element made of resin is fixed to the center of the bottom of the capacitor case made of thermoplastic resin, and the periphery of the center of the bottom is formed into a tapered shape. , it is possible to realize a safety device having sufficient operability even with a small diameter capacitor.

A second embodiment of the present invention will be described below with reference to the drawings.

3 and 4 are cross-sectional views of a capacitor safety device showing a second embodiment of the present invention. In the figure, 21 is a case made of thermoplastic resin, and 22 is an upper lid. 24 again
is a resin molded product provided at the center of the capacitor element 23, and is fixed to the element 23 by metallized resin 3o sprayed on both sides of the element 23, and is welded and fixed to the center part 25 of the bottom surface of the case. 26 is a tapered portion provided on the bottom surface of the case. Reference numeral 27 denotes a lead terminal, which is connected to the capacitor element 23 by a lead wire 29 via a weak point 28 .

The operation of the capacitor safety device configured as described above will be described below.

First, when the capacitor element 23 becomes abnormal, the internal pressure increases and the bottom surface of the case deforms. At this time, as shown in FIG. 4, the weak point 28 is cut and the electrical path is interrupted.

By changing the shape of the resin molded product 24 as shown in FIGS. 3 and 4, it is possible to narrow the case bottom central portion 26 and widen the area of the tapered portion 26. Figure 6 shows the test results of prototyping a capacitor by varying the diameter of the center of the bottom of the case, increasing the internal pressure by feeding air into the case at 20°C, and determining the pressure at which the weak point 28 is severed. . In the figure, the vertical axis represents the pressure inside the case at which the weak point is cut, that is, the operating pressure of the safety device, and the horizontal axis represents the diameter of the center of the bottom of the case.

Note that the diameter of the case used in this example was 3011 rl. Also, if the diameter is 15℃ or more, the weak point will not be cut,
Case destruction was observed. As is clear from the figure, by changing the diameter of the center of the bottom surface, it is possible to arbitrarily set the operating pressure of the safety device, and furthermore, the safety device has sufficient operability even with small diameter capacitors. When the device is realized, it can be achieved.

In addition, in both the first embodiment and the second embodiment, the thickness of the tapered part of the bottom of the case and the thickness of the center part are different. By making the other parts thinner, it is possible to further improve the operability of the safety device. Furthermore, providing a notch in the tapered portion or its end is also effective in improving the operability of the safety device.

Furthermore, as a method for fixing the resin molded product provided at the center of the capacitor element, adhesive or welding was used in the examples, but other methods such as screwing or shape fitting may also be used. Needless to say.

Effects of the Invention As described above, the present invention can realize an excellent capacitor safety device having sufficient reliability even in a small diameter capacitor.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a capacitor safety device according to a first embodiment of the present invention, and FIGS. 3 and 4 are cross-sectional views of a capacitor safety device according to a second embodiment of the present invention. FIG. 5 is a characteristic diagram showing the relationship between the operating pressure of the safety device and the diameter of the bottom center portion in the second embodiment, and FIGS. 6 and 7 are cross-sectional views of the conventional safety device of a capacitor. 14... Winding core, 15... Case bottom center part, 16... Case bottom tapered part, 18.
... Weak point, 24 ... Resin molded product, 25
...Central part of the bottom of the case, 26...Tapered part of the bottom of the case, 28...Weak point. Name of agent: Patent attorney Toshio Nakao and 1 other person11
-1-Case 12-Top 1 I3-Element I4-Win core I5-Main side Koinugun 16--Ichiran n Roteno stand Zhan P I7-Hikimi terminal Figure 1! 8-Yowuyoshu'615 Figure 3 Hemp 4 Figure 5 o, 5 to
/δ-String of bottom middle arrow part (Shou Misaki □ 6th whistle 1-m-Case Z--m11 3- Chord 4--Top 1 major part 7 figure

Claims (1)

[Claims] A draw-out terminal is provided on the upper lid of a case that has a winding core of a capacitor element inside, the pull-out terminal and the capacitor element are connected with a lead wire, and the bottom of the case is connected to a bottom central part to which the winding core is fixed; A safety device for a capacitor, which is made of thermoplastic resin and has a tapered bottom part that normally protrudes inward of the case and protrudes outward when internal pressure rises, and the lead wire is provided with a weak point that breaks when the internal pressure rises.