JPH10281916A - Sealing performance inspection device for electrolytic capacitor, and inspecting method by the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and easily inspect the quality of sealing performance of a seal part in an electrolytic capacitor. SOLUTION: A liquid tank 11 having an electrolytic capacitor C submerged in a stored liquid L is arranged within a sealed space 16, and the quality of sealing performance of the electrolytic capacitor C is judged from the presence of bubbles B generated from the electrolytic capacitor C when the sealed space 16 is exhausted to make negative pressure. The quality of sealing performance can be judged by visually confirming the presence of bubbles generated from the electrolytic capacitor C, or comparing the weight before inspection of the electrolytic capacitor C with the weight after inspection, or through an image processing of imaging and converting the electrolytic capacitor C within the liquid tank laid in a negative pressure state into an image data and analyzing the image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for inspecting the sealing performance of an electrolytic capacitor, which can surely and easily inspect the sealing performance at the sealing portion of the electrolytic capacitor.

[0002]

2. Description of the Related Art FIGS. 2 and 3 illustrate the internal structure of a general electrolytic capacitor by type.

The electrolytic capacitor 1 shown in FIG.
An anode foil formed by forming a dielectric oxide film by anodic oxidation on the surface of a roughened aluminum foil, and a cathode foil made of a roughened aluminum foil opposite to the anode foil, The capacitor element 2 is provided by individually connecting the corresponding external lead terminals 2a and 2b by caulking or the like, and then winding the same via a separator (electrolytic paper).

In the electrolytic capacitor 1, a separator (electrolytic paper) is impregnated with a driving electrolytic solution, and then a capacitor element 2 having a sealing body 3 mounted thereon is housed in a bottomed case 4 made of aluminum or the like. It is formed by winding and sealing the opening of the case 4.

In the electrolytic capacitor 5 shown in FIG. 3, the internal terminals 6a and 6b corresponding to the anode foil and the cathode foil having the same structure as in FIG. 2 are individually connected by caulking or the like. Thereafter, a capacitor element 6 wound around a separator (electrolytic paper) is provided.

[0006] The electrolytic capacitor 5 includes a separator (electrolytic paper) impregnated with a driving electrolytic solution, and a sealing member 7 formed by laminating a rubber plate on the outside of a bake plate. Of the internal terminal 6a and the external terminal 8a
After connecting the other internal terminal 6b and the external terminal 8b to the other connection fitting 7b, respectively, the capacitor element 6 is housed together with the sealing body 7 in a bottomed case 9 made of aluminum or the like. Is formed by winding and sealing the opening.

By the way, in the above electrolytic capacitor,
If there is a problem in the sealing performance secured between the sealing body and the case and the airtightness is not sufficiently maintained, the driving electrolyte may leak, resulting in a shortened life. And disadvantages such as unfavorable effects on performance characteristics.

For this reason, regarding the sealing performance of the electrolytic capacitor, the size and appearance of each product to be inspected are compared with non-defective products to be used as a reference to confirm the presence or absence of an abnormality, for example, at 95 degrees Celsius. By immersing in the warm water before and after to inflate the air in the case and confirming whether or not bubbles are generated at that time, the quality of the air bubbles is determined and defective products are eliminated.

[0009]

However, among the above-mentioned conventional discrimination methods, the conventional method of comparing the dimensions and appearance of products requires not only a highly skilled observation eye, but also There was a problem that there was no possibility that a defective product could be mistaken for a good product. In addition, the conventional method using hot water cannot be exposed to a high-temperature atmosphere for a long time due to the relationship between performance and quality. As a result, there is a possibility that a defective product is erroneously recognized as a good product. That is, there is a problem that 100% of defective products cannot be eliminated by any of the conventional methods.

[0010]

In order to solve the above-mentioned problems, an inspection apparatus according to the present invention comprises: a liquid tank formed so that an electrolytic capacitor can be immersed in a stored liquid; And a vacuum pump which is formed so as to be housed freely by shutting off from the outside air, and a vacuum pump which is connected to the pressure-resistant container so that air can be freely drawn. In this case, it is desirable that the liquid tank and the pressure-resistant container are formed so that the electrolytic capacitor immersed in the liquid can be seen through.

Further, in the inspection method according to the present invention, after a liquid tank formed by immersing an electrolytic capacitor in a stored liquid is arranged in a closed space, the closed space is evacuated to a negative pressure. In this case, the sealing performance of the electrolytic capacitor is checked based on the presence or absence of bubbles generated from the electrolytic capacitor in the liquid tank. In this case, the quality of the sealing performance can be checked by visually checking the presence or absence of air bubbles generated from the electrolytic capacitor, comparing the weight of the electrolytic capacitor before the inspection with the weight after the inspection, and determining whether the electrolytic capacitor in the liquid tank in the negative pressure state is in the closed state. It is desirable that the capacitor be visualized and converted into image data, and the image data be analyzed and subjected to image processing to make the determination.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic structural view of an example of an inspection apparatus according to the present invention, and the whole is formed so that an electrolytic capacitor C can be freely immersed in a stored liquid L. The apparatus comprises at least a liquid tank 11, a pressure-resistant container 15 for accommodating the liquid tank 11 from outside air, and a vacuum pump P arranged to freely draw air from the pressure-resistant container 15.

The liquid tank 11 is formed of, for example, transparent reinforced glass or reinforced plastic and has an appropriate depth determined by the height of the electrolytic capacitor C to be inspected. The liquid tank 11 contains an amount of liquid L, for example, pure water, which can completely immerse one or more electrolytic capacitors C, which are arranged, for example, stably and temporarily fixed to the stationary plate 12. An alcohol solution containing water and ethylene glycol can be stored.

A pressure-resistant container 15 for accommodating the liquid tank 11
Is made of, for example, a transparent reinforced glass or a reinforced plastic having airtightness capable of forming an enclosed space 16 completely shut off from outside air and having sufficient shape retention even when the pressure is lower than the atmospheric pressure. Is formed. The pressure vessel 15
For example, a mounting table 18 having a cushioning property may be provided on the inner bottom surface so that the liquid tank 11 can be stably mounted.

In addition, at an appropriate position of the pressure-resistant container 15, there is provided a connecting pipe portion 17 which is communicated with the sealed space 16 and protrudes outward, and is necessary for taking the liquid tank 11 in and out. An opening / closing means (not shown) having an appropriate structure such as an opening / closing lid is provided.

Further, the vacuum pump P is
Is connected to one end 21a, and the other end 21b is connected to the pressure-resistant container 15
By interposing the pipe 21 connected to the connection pipe portion 17 of the above, the air can be freely drawn from the sealed space 16 in the pressure-resistant container 15 and connected. In this case, it is desirable that the pressure in the closed space 16 of the pressure-resistant container 15 can be sequentially measured and confirmed by installing an appropriate pressure gauge (not shown).

The liquid tank 11 and the pressure-resistant container 15 have a part or all of the transparency that allows seeing through all of the electrolytic capacitor C immersed in the liquid L. Although it can be suitably used, it may be an opaque one that cannot see through the electrolytic capacitor C if necessary.

Next, an inspection method according to the present invention, which is realized by applying the above-described inspection apparatus according to the present invention, together with its operation, will be described below.

In the liquid tank 11, the object 1 to be inspected is
As shown in FIG.
Are individually and temporarily fixed in an upright state and are introduced, or are introduced in an individually falling down state or an upside down state.

A liquid L such as water or ethylene glycol is supplied into the liquid tank 11 into which the electrolytic capacitor C has been introduced until the amount thereof exceeds the sitting height of the electrolytic capacitor C. Completely immersive. In this case, after the liquid L is stored in the liquid tank 11, the electrolytic capacitor C may be immersed in the liquid L ex post facto.

After the electrolytic capacitor C is immersed in the liquid L in the liquid tank 11 as described above, the pressure-resistant container 15 is opened by appropriately operating opening / closing means such as an opening / closing lid. When the mounting table 18 is prepared, the liquid tank 11 is directly mounted on the mounting table 18 when the mounting table 18 is not prepared, and when the mounting table 18 is not prepared, the opening / closing means is closed. Thus, the liquid tank 11 is fixed in the closed space 16.

After the liquid tank 11 is fixed in the closed space 16 in this way, the vacuum pump P is driven to draw air from the closed space 16 of the pressure-resistant container 15 through the pipe 21. By performing such air bleeding for a predetermined time, the inside of the sealed space 16 gradually becomes a negative pressure state.

In this case, if the negative pressure formed in the closed space 16 is set to be 50% of the atmospheric pressure and air is drawn, the pressure test for the electrolytic capacitor C is performed twice. If the air is set at 25% of the atmospheric pressure and the air is drawn, a four-fold pressure test will be performed. In any case, even in a severe negative pressure state where the sealing performance of the electrolytic capacitor C is appropriately set. And it can be inspected.

After the above-described air drawing process, the electrolytic capacitor C immersed in the liquid L in the liquid tank 11
Expands according to Boyle-Charles' law in the volume of air enclosed therein. That is, as a result of the increase in the internal pressure of the electrolytic capacitor C, if the electrolytic capacitor C having a problem in sealing performance is mixed, bubbles B are generated as in the electrolytic capacitor C located at the right end in FIG. Then, by confirming the presence or absence of the bubble B, the electrolytic capacitor C having difficulty in sealing performance can be specified as a defective product.

In addition, the presence or absence of the bubbles B generated in this case can be determined only by visual inspection by the inspector, provided that both the pressure-resistant container 15 and the liquid tank 11 have a structure that can be clearly seen from the outside. Since it can be easily confirmed, the quality can be determined very easily.

If the pressure vessel 15 and the liquid tank 11 are both opaque and cannot be seen through from the outside, the liquid 1 enters the electrolytic capacitor C in which bubbles B are generated during the inspection, and the weight increases. The weight of the electrolytic capacitor C before the measurement is measured in advance, and the electrolytic capacitor C after the inspection is measured.
By comparing the weight with the weight, the quality can be determined.

Further, when the number of electrolytic capacitors C to be inspected at a time is large, the electrolytic capacitors C located in the rear row are hidden behind the electrolytic capacitors C located in the front row, so that they are visually checked. Becomes difficult. In such a case, the electrolytic capacitor in the liquid tank in a negative pressure state is visualized through an imaging means such as a video camera and visually checked, and further, if necessary, is digitally converted to image data. It is desirable to identify the electrolytic capacitor in which bubbles are generated by performing image processing for performing recognition and analysis by a computer, and then determine the quality of the electrolytic capacitor.

From the viewpoint of eliminating the possibility of erroneously recognizing a defective product as a non-defective product with respect to the sealing performance of the electrolytic capacitor C, the above-described visual confirmation work, confirmation work by weight comparison, and confirmation work by image processing are appropriately performed. It is desirable to carry out in combination. In this specification, “visually” means
This includes not only the case where the electrolytic capacitor C is viewed directly on site, but also the case where an image obtained through a television camera or a video camera is viewed indirectly via a screen.

[0029]

As described above, according to the inspection apparatus according to the present invention, the quality of the sealing performance of the electrolytic capacitor can be easily determined while the increase in the inspection cost is suppressed by simplifying the configuration. In addition, it is possible to contribute to the establishment of an inspection system for making a reliable determination.

Further, according to the inspection method of the present invention, the quality of the sealing performance can be reliably determined based on the presence or absence of air bubbles generated from the electrolytic capacitor immersed in the liquid. By eliminating the possibility of doing so, it is possible to always ship only good products as products.

In addition, when the presence or absence of the occurrence of bubbles is visually checked, the operation of judging the quality is further simplified.
It can contribute to speeding up.When checking the presence or absence of bubbles by comparing the weight of the electrolytic capacitor before the inspection with the weight after the inspection, compared to the visual confirmation work that can not keep your eyes on, Mistakes due to oversight can be eliminated, and the burden of checking work on the inspector can be further reduced.

Further, when the number of the electrolytic capacitors to be inspected is large, it is difficult to visually confirm the electrolytic capacitors. Therefore, the electrolytic capacitors in the liquid tank in the negative pressure state are visualized and digitally converted into image data. Through the image processing for analyzing the image data, the quality can be accurately determined.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an example of an electrolytic capacitor sealing performance inspection apparatus according to the present invention.

FIG. 2 is an explanatory view showing an internal structure of an example of a conventional electrolytic capacitor.

FIG. 3 is an explanatory view showing the internal structure of another example of a conventional electrolytic capacitor.

[Explanation of symbols]

 Reference Signs List 11 liquid tank 12 stationary plate 15 pressure-resistant container 16 sealed space 17 connection pipe section 18 mounting table 21 pipe L liquid P vacuum pump C electrolytic capacitor B bubble

Claims (6)

[Claims] 1. A liquid tank formed so that an electrolytic capacitor can be immersed in a stored liquid, a pressure container formed so as to be able to store the liquid tank by blocking the liquid tank from the outside air, An apparatus for inspecting sealing performance of an electrolytic capacitor, comprising at least a vacuum pump freely connected to air evacuation. 2. An apparatus for inspecting sealing performance of an electrolytic capacitor according to claim 1, wherein the liquid tank and the pressure-resistant container are formed so that the electrolytic capacitor immersed in the liquid can be seen through. 3. An electrolytic capacitor in a liquid tank when a liquid tank formed by immersing an electrolytic capacitor in a stored liquid is placed in a closed space, and the inside of the closed space is evacuated to a negative pressure. A method for inspecting the sealing performance of an electrolytic capacitor, comprising checking whether the sealing performance of the electrolytic capacitor is good or not based on the presence or absence of air bubbles generated from the electrolyte. 4. The method for inspecting the sealing performance of an electrolytic capacitor according to claim 3, wherein the quality of the sealing performance of the electrolytic capacitor is determined by visually checking the presence or absence of bubbles generated from the electrolytic capacitor. 5. The method for inspecting the sealing performance of an electrolytic capacitor according to claim 3, wherein the quality of the sealing performance of the electrolytic capacitor is determined by comparing the weight of the electrolytic capacitor before the inspection with the weight after the inspection. . 6. The quality of the sealing performance of the electrolytic capacitor is determined by imaging the electrolytic capacitor in the liquid tank in a negative pressure state, converting the image into image data, and generating air bubbles through image processing for analyzing the image data. 4. The method for inspecting sealing performance of an electrolytic capacitor according to claim 3, wherein the determination is made by specifying the electrolytic capacitor in use.