JPS6230486B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improvements in aluminum electrolytic capacitors, and in particular, to improving the sound quality characteristics of audio equipment by using an exterior metal case. Aluminum electrolytic capacitors generally consist of an anode electrode foil and a cathode electrode foil that are layered and wound together with a separator paper in between, and a cylindrical capacitor element impregnated with electrolyte is housed in a bottomed cylindrical aluminum case. The opening of the case is closed with a sealing member, and the opening end of the case is sealed by pressing the sealing member by winding or the like. At this time, the connection leads pulled out from the anode electrode foil and the cathode foil of the capacitor element are pulled out to the outside of the capacitor through the through hole provided in the sealing member, or
The lead-out lead is connected to a terminal portion attached to the sealing member, and is configured to be electrically connected to the outside. In the aluminum electrolytic capacitor constructed in this way, the outer metal case is JIS designation 1050,
Made of high purity aluminum material such as 1100 material with a purity of over 99.0%. The reasons for this are that it does not have any negative effects such as corrosion on the internal capacitor elements, it is easy to manufacture the case, it is easy to seam during assembly, and it is inexpensive compared to other materials. Incidentally, in recent audio equipment, attention has been paid to the fact that differences in the characteristics, materials, structures, etc. of the component parts greatly affect the sound quality of sound reproduction. Aluminum electrolytic capacitors are no exception to this; rather, aluminum electrolytic capacitors are one of the electronic components that have a very large effect on acoustics, and various improvements have been made to them. Ordinary aluminum electrolytic capacitors have an element structure in which a foil-like electrode foil is wound around the element, so when an alternating current or level-varying current, such as an audio signal, flows through the electrodes of the capacitor element, lines of magnetic force are generated from the capacitor element in response. do. However, since this capacitor element is covered with an aluminum exterior case, when the magnetic field lines pass through this exterior case, they generate eddy currents within the exterior case, and secondary magnetic field lines are generated from these eddy currents. However, these lines of magnetic force conversely generate current in the electrode foil of the capacitor element, which adds unnecessary signals and prevents faithful transmission of acoustic signals. This unnecessary addition of current is extremely small, and it is difficult to quantitatively understand the difference using measuring instruments, but it is known that it appears as a large difference that cannot be ignored when listening to music on an acoustic device. for example,
When comparing and listening to an electrolytic capacitor covered with an aluminum outer case and one with just a capacitor element without an outer case, the one with the outer case covered,
The reproduced sound band feels narrow, there is a lot of distortion, there is poor separation of individual instruments, and it can be seen that the aluminum exterior case has a negative effect on sound quality. In order to eliminate this influence of the aluminum exterior case, it has been proposed to use a synthetic resin case as the exterior case, but the synthetic resin case does not adhere well to the sealing member made of an elastic material, so adhesives may be used. However, the use of adhesive complicates the manufacturing process, and there is also the risk that some of the adhesive may enter the interior and cause corrosion. Furthermore, synthetic resin cases have drawbacks such as being vulnerable to external forces such as being dropped and being more expensive than aluminum cases. The present invention focuses on the fact that sound quality can be improved by using a certain type of aluminum alloy as an exterior case, and aims to improve the conventional drawbacks by using an aluminum alloy case to obtain an aluminum electrolytic capacitor with excellent sound quality. That is. The alloy case used in the present invention has a remarkable effect on improving sound quality, and is made of a stable material that does not cause corrosion or other effects on the capacitor element.
Moreover, it is necessary to select a material that does not impair workability during case processing and capacitor assembly processes. As a result of repeatedly making prototypes of various aluminum alloy cases for these purposes and listening to them, we found that an aluminum-tin alloy case was suitable for this purpose. This is considered to be because tin, which has a higher electrical resistance than aluminum, is scattered in the aluminum, which suppresses the generation of eddy currents and reduces the generation of secondary magnetic lines of force. The electrolytic capacitor of the present invention will be explained below.
As shown in FIG. 1, an electrolyte is applied to a capacitor element 4 which is formed by winding an anode-side electrode foil 1 and a cathode-side electrode foil 2, which have a dielectric oxide film formed on their surfaces, with a separator paper 3 in between. After impregnating it, it is placed in a bottomed cylindrical aluminum-tin alloy exterior case 5.
The opening of the exterior case 5 is closed with a sealing member 6 made of an elastic material, and the opening end of the exterior case 5 or the vicinity thereof is tightened and pressed to close the exterior case 5.
Seal the opening. Further, rod-shaped aluminum tabs 7a and 7b connected to each of the anode-side electrode foil 1 and the cathode-side electrode foil 2 are drawn out to the upper surface of the capacitor element 4, and the rod-shaped aluminum tabs 7
External lead wires 8a and 8b are connected to the tips of a and 7b, and these are led out through a through hole 9 provided in the sealing member 6. FIG. 2 shows another embodiment of the present invention,
Bottomed cylindrical aluminum-tin alloy exterior case 5
The capacitor element 4 is placed in the opening of the outer case 5, and the opening of the outer case 5 is closed with a sealing plate 12 in which an elastic member 11 is attached to a hard insulating plate 10. It is secured to the plate 12, and the open end of the exterior case 5 is wound inward to seal it. Further, the sealing plate 12 includes a plate-shaped terminal 14.
is attached, and the aluminum flat tabs 15a and 15b pulled out from the capacitor element 4 are connected to the terminal connection part 16 provided on the back surface of the sealing plate 12, and electrical connection is made with the external plate-shaped terminal 14. ing. As described above, the present invention is characterized in that the exterior of the capacitor element is made of an aluminum-tin alloy case. , the terminal shape is not limited to this embodiment and may be of any shape. Next, measurement of the effect of the present invention will be described. Judging the effectiveness is difficult because it is difficult to quantitatively understand it using measuring instruments.
I did a comparative listening session using musical sounds. The listening method is to connect an aluminum electrolytic capacitor (rated 50W.V., 4.7μ) to the coupling circuit of the audio amplifier.
F) was inserted, and the difference in sound quality was compared between a capacitor element with the same rating and no outer case as a reference and one covered with various outer cases. The evaluation criteria for comparison was 5 levels as shown in the table below, with the sound quality of the caseless capacitor being set as 0.

【table】

[Table] 4 tones were sampled by 7 listeners, namely (A)
This was done for symphony, (B) chamber music, (C) jazz, and (D) vocals, and the upper and lower ranges of the average value and standard deviation value for each tone and the overall average were determined and shown in Figure 3. As is clear from this evaluation result, the reproduced sound of an electrolytic capacitor using an ordinary aluminum case (purity of 99.0% or more) is clearly inferior to the standard sound quality without a case. On the other hand, the electrolytic capacitor using the aluminum-tin alloy exterior case of the present invention has a remarkable sound quality improvement effect, and it can be seen that the sound quality is comparable to, or in some cases superior to, an electrolytic capacitor without a case. . Regarding the amount of tin added, as shown in the results in Figure 3, if the amount of tin added is less than 1%, the sound quality improvement effect will not be fully manifested, while if it exceeds 10%, the improvement effect will be significantly improved. The result is almost the same. In addition, if the amount of tin added is 20% or more, the outer case becomes extremely hard, which has the disadvantage that the seaming process during case manufacturing and capacitor assembly will not work properly, and the increased amount of tin will also make the case more expensive. Therefore, the appropriate amount of tin to be added in the alloy case of the present invention is 1% to 20%. As described above, the aluminum electrolytic capacitor of the present invention can easily improve sound quality without increasing the number of processes or increasing costs unlike synthetic resin cases, and does not require any changes to the conventional manufacturing process. It is possible to improve the sound quality of audio equipment.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing the internal structure of the aluminum electrolytic capacitor of the present invention, FIG. 2 is a partial cross-sectional view showing another embodiment of the aluminum electrolytic capacitor of the present invention, and FIG. 3 is a partial cross-sectional view of the electrolytic capacitor of the present invention. It is a graph showing the trial listening results. 4... Capacitor element, 5... Exterior case, 6... Sealing member, 12... Sealing plate.

Claims (1)

[Scope of Claims] 1. An aluminum electrolytic capacitor in which a wound aluminum electrolytic capacitor element is enclosed in a metal exterior case and sealed with an exterior case opening member, wherein the material of the metal exterior case is aluminum. An aluminum electrolytic capacitor characterized by being made of a tin alloy. 2. The aluminum electrolytic capacitor according to claim 1, wherein the aluminum-tin alloy forming the outer case has a tin content of 1% to 20%.