JPS5940767Y2 - Electrolytic capacitor - Google Patents

Description

[Detailed description of the invention] This invention relates to an electrolytic capacitor that has an explosion-proof mechanism by providing a small hole or cut groove in the constricted part of the outer cylindrical case in which the capacitor element is enclosed. The present invention provides an electrolytic capacitor having the following features.

Conventionally, in electrolytic capacitors, gas is abnormally generated from the capacitor element due to electronic short circuits and overvoltage application, and the pressure inside the outer casing that encloses the capacitor element becomes abnormally high, causing the outer casing to explode. There is a risk that the electrolyte will scatter around and corrode other parts, so when the pressure inside the outer case becomes high, the gas inside the outer case is discharged to the outside to prevent the case from exploding. ku°
Explosion-proof mechanisms have become essential.

Various explosion-proof mechanisms have been devised in the past, but
A typical example is an elastic sealing body made of rubber or the like, in which a capacitor element is housed in a bottomed cylindrical outer case, and the opening of the outer case is closed to enclose the capacitor element inside the outer case. There is an explosion-proof valve with a hole made from the inside so that the thickness is thinner than other parts, and when the pressure inside the outer case becomes high, the end face of the hole is destroyed and the outer case is damaged. Can prevent explosions.

By the way, when such electrolytic capacitors are used, they are often mounted on a printed circuit board, etc. with the elastic sealing side facing down, and due to the need to downsize electronic devices, they are often mounted in close contact with the printed circuit board. However, if the elastic sealing body side is installed in close contact with the printed circuit board in this way, the thin part of the elastic sealing body that serves as an explosion-proof valve will be reinforced by the printed circuit board, and the pressure inside the outer cylinder case will increase. However, it may happen that the explosion-proof valve does not operate.

Recently, in small electrolytic capacitors, a method has been adopted in which the opening of the outer cylindrical case is sealed with an elastic sealing member and then resin is injected into the opening in order to improve the sealing performance.

That is, in this case, it is no longer possible to provide an explosion-proof mechanism by providing holes in the elastic sealing body.

With this in mind, various types of explosion-proof mechanisms have been devised by modifying the outer cylinder case.

For example, in U.S. Patent No. 3,204,156, an explosion-proof part is created by making a cut in the side wall of the outer case to form a thin wall part, and in US Pat. Japanese Utility Model Publication No. 50-42356, in which a cross-shaped notch of the required depth was made at the bottom of the outer cylinder case to create an explosion-proof part, Publication No. 1987-3376, in which a circular thin section was formed on the bottom of the outer cylinder case. Japanese Utility Model Publication No. 51-3377, in which an explosion-proof part was created by providing a thin wall with a different wall thickness, and Japanese Utility Model Publication No. 1983-3377, in which an explosion-proof part was created by forming a petal-shaped part arranged radially from a substantially central point at the bottom of an outer cylindrical case. Publication No. 51-8678, Japanese Utility Model Publication No. 51-8676, in which a circular protrusion with a smaller diameter than the bottom is provided at the bottom of the outer cylinder case to form an explosion-proof part, the bottom of the outer cylinder case is divided into four by two center lines. Jikkosho 51, when one of the two sets of symmetrical fan-shaped surfaces was used as a fan-shaped convex part as an explosion-proof part.
Various types of electrolytic capacitors have been devised that eliminate the drawbacks of conventional explosion-proof mechanisms, such as those seen in the electrolytic capacitors disclosed in Japanese Patent No. 8680.

However, all of these devices have an explosion-proof part on the bottom or side of the outer case, so depending on how you install them, the explosion-proof part may be covered by the electronic device's chassis, etc., and the explosion-proof part may not work properly. The disadvantage is that it does not work.

In particular, for products with an explosion-proof part on the bottom, the explosion-proof part is exposed outside the insulating tube, and the explosion-proof part may be torn during transportation, or people with little knowledge about the explosion-proof mechanism of electrolytic capacitors may accidentally sharpen the explosion-proof part. There was a risk that the explosion-proof function would be lost before the explosion-proof section could fulfill its role due to being hit with something.

The present invention was developed to solve these conventional drawbacks by observing the explosion of electrolytic capacitors that do not have an explosion-proof function, and devising the most efficient explosion-proof structure.

As a result of observing when an electrolytic capacitor sealed with an elastic sealing body that does not have an explosion-proof function explodes, the inventors of the present invention found that
It was discovered that when an explosion occurs, the elastic seal always expands outward, and when it can no longer support the rise in internal pressure, the elastic seal protrudes.

For this reason, the present invention utilizes the swelling of the elastic sealing body that occurs before the explosion of an electrolytic capacitor sealed with an elastic sealing body. Since the end face of the elastic sealing member extends up to the constricted part of the outer cylindrical case, if a small hole or cut groove is provided in the constricted part, it will function as an explosion-proof part.

Thereby, the gas generated inside the outer cylindrical case can be dissipated to the outside through the small holes or notches of the constricted portion, thereby preventing an explosion.

According to the explosion-proof structure of the present invention, it is possible to provide an explosion-proof function with little variation without being affected by the material of the elastic sealing body or changes over time.

FIG. 1 shows an electrolytic capacitor according to an embodiment of the present invention. Reference numeral 1 denotes an outer cylindrical case in which a capacitor element is housed.

Reference numeral 2 denotes an elastic sealing body made of rubber or the like that closes the opening of the outer cylinder case 1. The elastic sealing body 2 is inserted into the opening of the outer cylinder case 1, and is set to close the opening of the outer cylinder case 1. The elastic sealing body 2 and the outer tube case 1 are pressed together by the constricted portion 8 formed by squeezing the outer circumferential portion inward, and the opening periphery of the outer tube case 1 is further drawn toward the elastic sealing body 2. The elastic sealing body 2 and the open end of the outer cylindrical case 1 are sealed by bringing the elastic sealing body 2 and the open end of the outer cylinder case 1 into close contact with each other by the curled portion 4 formed by curling.

Reference numeral 5 denotes a small hole provided in the constricted portion 3 of the outer cylinder case 1, and this small hole 5 serves as an explosion-proof portion.

Note that 6 is a lead for drawing out the capacitor element.

Table 1 shows the results of investigating the operating status of the electrolytic capacitor of the present invention shown in Fig. 1 as an explosion-proof function when the position and number of small holes 5 are changed as shown in Fig. 2 a and e. .

In addition, the case size of the sample is 12.5sn @ x 25r
rrmt ・JIS O4 type electrolytic capacitor 2
A test was conducted by connecting a 3.3Ω protective resistor to the sample and applying 125V-AC to the sample.

As is clear from Table 1, when the number of small holes 5 is 2 to 5, the valve reliably operates as an explosion-proof valve.

Incidentally, if the number of small holes 5 increases, the accuracy of operation will increase, but it will require more man-hours, so it is preferable to provide an appropriate number of 2 to 5 holes L5.

FIG. 3 shows an electrolytic capacitor according to another embodiment of the present invention, in which a notch 7 is used instead of the small hole 5 as an explosion-proof part.

Table 2 shows the explosion-proof function of the electrolytic capacitor of the present invention shown in Fig. 3 when the number of notches 7 and the length of the notches 7 are changed as shown in Fig. 4 a to C. The results of investigating the operating status of the system are shown below.

Note that the sample and test method were the same as in the above example.

As is clear from Table 2, if an appropriate length and number of cut grooves are provided, the valve will surely operate as an explosion-proof valve.

In addition, when the cut groove 7 as shown in FIG. 4C is provided, it does not operate like the other examples, but operates at a slightly higher pressure.

As described above, according to the present invention, an explosion-proof function can be provided by simply providing a small hole or a notch in the constriction part of the outer cylinder case, and it operates reliably, and since it is provided in the constriction part, Even when a large number of electrolytic capacitors are arranged close to each other, a space is created near the explosion-proof part, and effects of high practical value can be obtained, such as the fact that the explosion-proof function is not lost.

[Brief explanation of drawings]

Figure 1 is a front view showing an electrolytic capacitor according to one embodiment of the present invention, Figures 2 a - e are explanatory diagrams showing samples of tests conducted on the capacitor, and Figure 3 is a front view showing an electrolytic capacitor according to another embodiment of the present invention. A front view showing an electrolytic capacitor; FIGS. 4A to 4C are front views showing samples of tests conducted on the capacitor. DESCRIPTION OF SYMBOLS 1... Outer cylinder case, 2... Elastic sealing body, 3... Squeezed part, 4... Curled part, 5
...Small hole, 7... Cut groove.

Claims (3)

[Scope of utility model registration request] (1) An elastic sealing body is inserted into the opening of the outer cylinder case, and the diaphragm formed by squeezing the outer peripheral part near the opening inward and the periphery of the opening of the outer cylinder case are elastically sealed. An electrolytic capacitor sealed by a curled portion formed by curling toward the body, and provided with an explosion-proof portion in the constricted portion of the outer cylindrical case. (2) Scope of utility model registration claim 1 where the explosion-proof part is a small hole
Electrolytic capacitors as described in section. (3) The electrolytic capacitor according to claim 2, in which the explosion-proof part is a cut groove of an appropriate length. An electrolytic capacitor according to scope 1.