JPS6242520Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a capacitor with a safety device.

In the conventional capacitor, as shown in FIG.
When the internal pressure rises due to an abnormality, the expansion portion 3 expands and the lead wire 5 connecting the capacitor element 1 and the terminal 4 is pulled and disconnected. However, as shown in the figure, when two capacitor elements are housed in one case 2, at least two lead wires 5 (at least one lead wire 5 from each capacitor element 1) must be connected. It is necessary to cut the lead wire 5.
The internal pressure required to break the case 2 and the top lid 5 is higher than that of a single lead wire, and the structure is changed because it is necessary to increase the strength of the joint between the case 2 and the top cover 5, which will prevent the lead wire 5 from breaking and cause the sealing part to break. It had drawbacks such as being complicated and expensive.

The present invention aims to eliminate the above-mentioned drawbacks and to provide a capacitor with a safety device that is inexpensive and capable of reliably cutting the lead wire of the capacitor in the event of an abnormality.

That is, in a capacitor in which a plurality of capacitor elements are housed in one case, the case is provided with a multi-stage expansion section that expands due to internal pressure, and the expansion of the expansion section causes each capacitor element to This is a capacitor with a safety device configured so that the connected lead wires are sequentially disconnected due to the pressure time difference.

The present invention will be described below with reference to embodiments shown in FIGS. 2 to 4.

Figure 2 is a cross-sectional view of a capacitor with a safety device when two capacitor elements are housed in a case.
Lead wires 15a, 15a', 15b, 15b' are connected to the capacitor elements 11a, 11b, respectively. First, the capacitor elements 11a, 11b and the holding plates 17a, 17b are housed in the case 12. Next, a concave groove 18a is formed in the upper part of the holding plate 17a for fixing the capacitor element 11a. Then, a concave expansion portion 19a that expands as the internal pressure increases is formed. Similarly, after forming a concave groove 18b in the upper part of the holding plate 17b for fixing the capacitor element 11b, a concave expansion part 19b that expands as the internal pressure increases is formed, and the terminals 14a, 14a', 14b are formed. , 14b' are fixed to the upper cover 16, which is fitted into the opening of the case 12 and tightened. The depth of the concave expansion part 19a provided in the lower part of the case 12 is shallower than the depth of the expansion part 19b provided in the upper part.

Next, to explain the operation of the safety device, an abnormality occurs in either capacitor element 11a or 11b, the internal temperature of the capacitor rises, thermal destruction occurs, gas is generated, and the internal pressure rises to reach a predetermined pressure. Then, the concave expansion portion 19b that is easier to expand first stretches, thereby pulling the lead wire 15b and cutting the weak point 20b provided on the lead wire 15b. That is, as shown in FIG. 3, the upper stage capacitor element 11b is electrically disconnected from the circuit. If the lower capacitor element 11a is abnormal, the internal pressure will continue to rise, so the expansion part 19a will expand as shown in FIG. 4, and the weak point 20a of the lead wire 15a will break, causing the capacitor element 11a to is also electrically disconnected from the circuit. Note that the lower capacitor element 11a
Similarly, if an abnormality occurs in only the lead wires 15b and 15a, the lead wires 15b and 15a will be sequentially disconnected due to the pressure time difference.

The lead wire 15b' is connected to the shortest distance from the metal connection part on the upper part of the capacitor element 11b to the connection part of the terminal 14b' and the expansion parts 19a and 1.
The length must be greater than the sum of the maximum elongation dimension of 9b. In addition, the lead wire 15b is connected to the terminal 1 from the metallic connection part at the bottom of the capacitor element 11b.
It is desirable that the length be the sum of the shortest distance to the connecting portion of the expansion portion 19b and a dimension approximately 1/2 of the maximum elongation dimension of the expansion portion 19b. Similarly, the lead wire 15a' must have a length equal to or longer than the sum of the shortest distance from the metal connection part on the upper part of the capacitor element 11a to the terminal 14a' and the maximum extension dimension of the expansion parts 19a and 19b.
The lead wire 15a has a dimension that is approximately 1/2 of the shortest distance from the lower metallic contact part of the capacitor element 11a to the connection part of the terminal 14a, the maximum elongation dimension of the expansion part 19b, and the maximum elongation dimension of the expansion part 19a. It is desirable that the length be the same as the above. Note that the lead wires 15a and 15b are connected to the capacitor elements 11a and 11 as shown in FIG.
It is better to insert the winding core part b.

Since the capacitor with safety device of the present invention is constructed as described above, the capacitor element 11
If an abnormality occurs in at least one of the lead wires 15a and 11b, generating gas and increasing the internal pressure, tension will not be applied to the two lead wires 15a and 15b at the same time, and they will be cut one by one due to the pressure time difference. To securely disconnect the lead wire and release the capacitor from the circuit. No high pressure is applied to the joint between the upper lid 16 and the case 12, and there is no fear that the upper lid 16 or the capacitor elements 11a, 11b will pop out of the case 12, resulting in an extremely safe capacitor.

In the above embodiment, the case where there are two capacitor elements has been explained, but cases with three or more capacitor elements can be manufactured in the same manner, and the shape and position of the expansion part can be changed as necessary. can. Furthermore, the order of forming the expansion portion and assembling the product is not limited to the above embodiment.

As mentioned above, the capacitor with a safety device of the present invention has a relatively low internal pressure and can operate reliably, which is extremely advantageous in terms of safety and has great practical value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional capacitor with a safety device, Fig. 2 is a sectional view of an embodiment of a capacitor with a safety device of the present invention, and Figs. 3 and 4 are a sectional view of a capacitor with a safety device of the present invention. It is an operation explanatory diagram. 11a, 11b: capacitor element, 12: case, 15a, 15a', 15b, 15b': lead wire, 19a, 19b: expansion section.

Claims (1)

[Scope of utility model registration request] A plurality of capacitor elements are housed in a single case in vertical rows, and a holding plate supported by a concave groove provided in the case is arranged between each of the capacitor elements and on top of the topmost capacitor element. , a concave expansion part is formed in the case that expands one by one as the internal pressure increases for each capacitor element, and the upper part of the expansion part is always deeper than the lower part. A capacitor with a safety device configured to elongate more quickly and sequentially cut the lead wires connected to each of the capacitor elements due to the pressure time difference.