JPH051064Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an electrolytic capacitor, and more specifically, to a safety device thereof.

[Conventional example]

Normally, when an electrolytic capacitor is used within the rated range, the pressure inside the case rarely increases to exceed the sealing force. however,
When used at a voltage higher than the rated value, when an alternating current exceeding the allowable ripple current is applied, or when the positive and negative terminals are connected in reverse, hydrogen gas, etc. is generated, and the gas pressure eventually reduces the sealing force. There is a danger that the sealing plate may come off or the case may fly off.

Therefore, various safety devices have been proposed in the past, but they can be broadly divided into two methods: one in which a thin fragile part is formed in the case, and the other in which a valve member called an explosion-proof valve is attached to a sealing plate. The former is mainly used for small-capacity capacitors, and the latter is applied to large-capacity capacitors, and an example using an explosion-proof valve is illustrated in FIG.

That is, in this type of safety device, for example, a through hole 2 of a predetermined diameter is bored in a sealing plate 1 made of molded resin, and a cap-shaped valve 3 made of an elastic material such as rubber is inserted into the through hole 2 of the sealing plate 1. It is configured by fitting from the back side. As is well known, after the capacitor element 5 is housed in the bottomed metal case 4, the sealing plate 1 is placed in the opening and fixed by caulking. Note that a pair of internal terminals 5a drawn out from the capacitor element 5,
5b is a screw terminal 6a which is provided through the sealing plate 1;
6b etc.

According to this configuration, when gas is generated due to incorrect use and the internal pressure of the case reaches a predetermined pressure, the valve 3 ruptures or escapes through the through hole 2 and the gas is released to the outside of the case 4. .

[Problem that the invention attempts to solve]

In the conventional example described above, since it is necessary to fit the valve 3 into the through hole 2 of the sealing plate 1 before attaching the sealing plate 1 to the metal case 4, there are the following drawbacks.

That is, the internal terminals 5a, 5b are attached to the electrode foil constituting the capacitor element 5, for example, by caulking, but at this time the oxide film of the electrode foil is damaged. Therefore, in order to repair the problem, first, after storing the capacitor element 5 in the metal case 4,
Next, perform aging. At this time, a relatively large amount of gas is generated, so during this aging process, the sealing plate 1
Done without. After that, the opening of the metal case 4 is caulked to the rubber sealing 7 of the sealing plate 1.
The product is then aged and shipped after passing through a predetermined inspection process, but the gas generated during this second aging remains trapped in the case 4, resulting in a shortened product life.

Regarding this point, Japanese Unexamined Patent Publication No. 13872/1983 states:
A capacitor overpressure valve is disclosed that is configured to be attached to a capacitor casing at the end of an electrolytic capacitor assembly process. That is, the overpressure valve includes a generally cylindrical body of resilient material for biasing the valve body. Two flanges are formed on the periphery of the main body, and a spherical head is connected to the bottom of the main body via an extension. On the other hand, a recess into which the cylindrical body is fitted is formed on the sealing plate side, and a through hole for degassing and a mounting hole into which the spherical head is fitted are formed at the bottom of the recess. and is drilled.

When assembling, first insert the separately prepared valve body into the recess to cover the gas venting hole, then install the cylindrical main body into the recess,
Snap the spherical head into the mounting hole,
The cylindrical body presses the valve body.

According to this, the sealing plate can be attached from the surface side (outside the capacitor), so it is possible to close the gas vent hole even after secondary aging, but this has the following disadvantages. is left behind.

In other words, in addition to the through-hole for degassing, the sealing plate requires a separate mounting hole for fitting the spherical head, which not only requires additional man-hours but also requires drilling the mounting hole. As a result, the strength of the sealing plate itself is undeniably reduced. Although it is possible to compensate for the decrease in strength by selecting a material with higher strength, an increase in cost is unavoidable.

In addition, since two parts are required: a valve body that directly closes the gas vent hole and a cylindrical body that presses the valve body, it is labor-intensive to assemble and is unfavorable in terms of cost.

[Means to solve the problem]

This idea was devised in view of the above-mentioned conventional circumstances, and its structural features are that the capacitor element is housed in a cylindrical metal case with a bottom, and a through hole is provided at the opening of the case. In an electrolytic capacitor equipped with a sealing plate having a safety device consisting of a valve member that elastically fits into the capacitor, the valve member has a valve head substantially larger in diameter than the through hole, and a valve head that is substantially larger in diameter than the through hole. has a substantially smaller diameter and a longer axial length than the through hole, and has one end connected to the valve head, and the other end of the valve shaft has a diameter larger than the inner diameter of the through hole. The stopper is comprised of a plurality of legs that are large in size and are formed to spread radially.

[Effect]

According to the above-mentioned valve member, the gas can be vented during aging, and then the through hole of the sealing plate can be closed.

Further, since the valve member has a single structure, the installation work is simple and it is advantageous in terms of cost.

Furthermore, there is no need to make any holes in the sealing plate other than the through holes for gas venting.

〔Example〕

Hereinafter, embodiments of this invention will be described in detail with reference to FIGS. 1 to 4. Although only the main parts are shown in these figures, the metal case,
Capacitor elements, terminal members, etc.
It should be understood that this is the same as the conventional example shown in the figure.

Referring to FIGS. 1 and 2 showing the first embodiment, the structure of the sealing plate 1 having the through hole 2 is the same as the conventional one, but according to this invention, the through hole 2 is A valve member 1 as shown in FIG.
0 is attached. That is, this valve member 10 is entirely made of an elastic material such as rubber, and includes a valve head 11 having a substantially larger diameter than the through hole 2, and a valve shaft with one end connected to the valve head 11. 12, and a stopper 13 formed at the other end of the valve shaft 12. The valve stem 12 has a substantially smaller diameter than the through hole 2 so as to form a gas vent gap therebetween, and its axial length is longer than that of the through hole 2. According to this embodiment, the stopper 1
3 is perpendicular to the axis of the valve stem 12 at the other end;
It also has four legs 13a formed, for example, in a cross shape so as to engage with the periphery of the through hole 2.

As shown in FIG. 1a, this valve member 10 is fitted into the through hole 2 from the back side of the sealing plate 1 (inside the metal case) with the valve head 11 first. In this case, in the valve member 10, as shown in FIG. It is fitted in the state in which it is placed. The sealing plate 1 is placed in the opening of the metal case 4 (see FIG. 5) in the state shown in FIG. 5B, and after being fixed by caulking, it is subjected to aging. The gas generated during this aging is discharged to the outside through the gap. After aging, the valve head 11 is forced into the borehole 2, as shown in FIG. 1c. During actual use, when the internal pressure of the case reaches a predetermined pressure due to an abnormality in the product, the valve head 11 comes off the through hole 2 as shown in FIG. 1b, and gas is released.

A second embodiment is shown in FIGS. 3 and 4. The valve member 10' according to this embodiment includes a valve head 11, a valve stem 12, and a stopper 13 that are substantially similar to those of the above embodiment, but the legs 13a of the stopper 13 are at an acute angle with respect to the axis of the valve stem 12. The points intersecting the valve head 1, that is, each leg 13a...
The difference is that it is tilted toward the first side.

After the aging treatment, this valve member 10' is fitted from the front side of the sealing plate 1 into the through hole 2 from the stopper 13 side as shown in FIG. 3a, and as shown in FIG. 3b. The valve head 11 is forcibly pushed in and the through hole 2 is closed. In this case, each leg 13a of the stopper 13 is tilted toward the valve head 11, so that it can be easily fitted into the through hole 2. During actual use, if the internal pressure of the case reaches the specified pressure due to a product malfunction,
As shown in FIG. 3b, the valve head 11 is removed from the through hole 2 and gas is released.

[Effect of idea]

As explained above, according to this invention, a valve member is provided that can close the gas vent hole after releasing the gas generated during the aging process. Since it is a component, the installation work can be easily done with one touch, which reduces the number of man-hours and is also advantageous in terms of cost. Further, since no holes other than gas vent holes are required in the sealing plate, there are advantages such as no new strength problems or cost problems arise.

[Brief explanation of drawings]

Figures 1 a to c are explanatory diagrams of the operation of the first embodiment of the invention, Figure 2 is a perspective view of a valve member used in the same embodiment, and Figures 3 a to c are the second embodiment of the invention. FIG. 4 is a perspective view of a valve member used in the example, and FIG. 5 is a sectional view showing a conventional example. In the figure, 1 is a sealing plate, 2 is a through hole, 4 is a metal case, 5 is a capacitor element, 10 and 10' are valve members,
11 is a valve head, 12 is a valve stem, and 13 is a stopper.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A capacitor element is housed in a cylindrical metal case with a bottom, and a through hole in the opening of the case and a valve member that elastically fits into the through hole. In an electrolytic capacitor equipped with a sealing plate having a safety device, the valve member includes a valve head having a substantially larger diameter than the through hole, and a valve head having a substantially smaller diameter than the through hole and the same through hole. has an axial length longer than
A valve stem having one end connected to the valve head, and a stopper formed of a plurality of legs having a size larger than the inner diameter of the through hole and radially expanding at the other end of the valve stem. An electrolytic capacitor characterized by: (2) The electrolytic capacitor according to claim 1, wherein the leg intersects the valve shaft at right angles. (3) The electrolytic capacitor according to claim 1, wherein the leg intersects the valve shaft at an acute angle. (4) The electrolytic capacitor according to claim 1, wherein the valve member is fitted into the through hole from the valve head side from the back side of the sealing plate. (5) The electrolytic capacitor according to claim 1, wherein the valve member is fitted into the through hole from the stopper side thereof from the surface side of the sealing plate.