Electrolytic capacitors

Abstract

To provide electrolytic capacitors that offer greater flexibility in selecting the material of the capacitor element while also improving sound quality when used in audio equipment. [Solution] The electrolytic capacitor 1 comprises a capacitor element 2, a bottomed cylindrical outer case 3 that houses the capacitor element 2 impregnated with electrolyte, and a sealing body 4 that seals the opening of the outer case 3, wherein an electrically insulating sheet 5 mainly composed of wool fibers is placed between the inner surface 3a of the outer case 3 and the capacitor element 2.

Description

Technical Field

[0001] The present invention relates to an electrolytic capacitor, particularly an electrolytic capacitor used in audio equipment.

Background Art

[0002] Conventionally, an electrolytic capacitor is configured by overlapping an anode foil and a cathode foil through a separator, winding them to form a capacitor element, impregnating the capacitor element with an electrolytic solution, housing it in an exterior case, and sealing an opening with a sealing body. In audio equipment, electrolytic capacitors are used for applications such as power circuit filters, coupling of each circuit block, and decoupling. It is known that the quality of the reproduced sound changes depending on the materials used for such electrolytic capacitors for acoustics.

[0003] In Patent Document 1, an electrolytic capacitor using a mixed paper containing wool fibers as a separator has been proposed in order to obtain a reproduced sound quality with a good balance from low frequencies to high frequencies.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, according to the electrolytic capacitor of Patent Document 1, while the balance of sound is improved, there is a limitation that the material of the separator of the capacitor element is limited to mixed paper containing wool fibers. It is desired that an electrolytic capacitor for acoustics can achieve higher sound quality while ensuring a degree of freedom in selecting the material of the capacitor element.

[0006] The objective of the present invention is to provide an electrolytic capacitor that can improve sound quality when used in audio equipment, while ensuring a degree of freedom in selecting the material of the capacitor element. [Means for solving the problem]

[0007] An electrolytic capacitor according to an embodiment of the present invention comprises a capacitor element, a bottomed cylindrical outer case housing the capacitor element impregnated with an electrolyte, and a sealing body that seals the opening of the outer case, characterized in that an electrically insulating sheet mainly composed of wool fibers is disposed between the inner surface of the outer case and the capacitor element.

[0008] This configuration, by placing an electrically insulating sheet primarily composed of wool fibers between the inner surface of the outer casing and the capacitor element, can improve the sound quality of audio equipment using electrolytic capacitors. Furthermore, because the sound quality is improved by the sheet placed between the capacitor element and the outer casing, it is possible to improve sound quality while maintaining flexibility in the selection of the capacitor element material.

[0009] In an electrolytic capacitor according to an embodiment of the present invention, the sheet may be placed between the inner surface of the bottom of the outer casing and the capacitor element.

[0010] This configuration allows for improved sound quality in audio equipment using electrolytic capacitors, while suppressing short circuits between the inner surface of the bottom of the outer casing and the capacitor element, thanks to an electrically insulating sheet primarily composed of wool fibers.

[0011] In the electrolytic capacitor according to an embodiment of the present invention, the sheet may be a felt sheet made of wool fibers.

[0012] This configuration allows for improved playback sound quality in audio equipment that uses electrolytic capacitors.

[0013] Furthermore, in the electrolytic capacitor according to an embodiment of the present invention, the capacitor element is formed by overlapping an anode foil and a cathode foil with a separator in between and winding them, and the separator may be made of a different material than the sheet.

[0014] This configuration allows for improved sound quality while ensuring flexibility in selecting the material for the capacitor element separator. [Effects of the Invention]

[0015] According to the electrolytic capacitor of the present invention, it is possible to improve sound quality when used in audio equipment while ensuring freedom in the selection of the material of the capacitor element. [Brief explanation of the drawing]

[0016] [Figure 1] This is a cross-sectional view showing the configuration of an electrolytic capacitor according to an embodiment of the present invention. [Figure 2] This is an exploded perspective view of a capacitor element in an electrolytic capacitor according to an embodiment of the present invention. [Modes for carrying out the invention]

[0017] Hereinafter, an electrolytic capacitor 1 according to one embodiment of the present invention will be described with reference to Figures 1 and 2.

[0018] As shown in Figure 1, the electrolytic capacitor 1 comprises a capacitor element 2, a bottomed cylindrical outer case 3 in which the capacitor element 2 impregnated with electrolyte is housed, a sealing body 4 that seals the opening of the outer case 3, and a sheet 5 disposed between the inner surface of the outer case 3 and the capacitor element 2. Furthermore, the electrolytic capacitor 1 of this embodiment is a chip-type electrolytic capacitor surface-mounted on a substrate, and further comprises an electrically insulating base plate 6.

[0019] As shown in FIG. 2, the capacitor element 2 is formed by overlapping an anode foil 21 and a cathode foil 22 with a separator 23 interposed therebetween and winding them. The anode foil 21 is formed by forming an oxide film on a valve metal foil such as an aluminum foil. The anode foil 21 and the cathode foil 22 are respectively connected to an anode lead terminal 7 and a cathode lead terminal 8. In FIG. 2, the width of the separator 23 is larger than the widths of the anode foil 21 and the cathode foil 22, and both ends in the width direction of the anode foil 21 and the cathode foil 22 are located inside both ends in the width direction of the separator 23. The width of the separator 23 may be substantially the same as the widths of the anode foil 21 and the cathode foil 22. An insulating paper having electrical insulation is used for the separator 23. The separator 23 is mainly composed of, for example, cellulose. The separator 23 preferably does not contain wool fibers. This is because if the inclusion of wool fibers is essential, there is a possibility that the functions required for the separator 23 cannot be fully exhibited. The separator 23 holds an electrolyte. The electrolyte held in the separator 23 may be only an electrolytic solution, or may be both a solid electrolyte mainly composed of a conductive polymer resin and an electrolytic solution.

[0020] As shown in FIG. 1, the anode lead terminal 7 and the cathode lead terminal 8 are respectively drawn out to the outside through holes 4a and 4b formed in the sealing body 4 and holes 6a and 6b formed in the seat plate 6. The anode lead terminal 7 and the cathode lead terminal 8 drawn out to the outside from the seat plate 6 are respectively bent and arranged along the bottom surface of the seat plate 6.

[0021] The material of the exterior case 3 is, for example, aluminum. The exterior case 3 is composed of a bottom portion 3a and a side wall portion 3b. The bottom portion 3a of the exterior case 3 is circular. That is, the exterior case 3 is a bottomed cylindrical shape. The shape of the bottom portion 3a of the exterior case 3 may be elliptical. The sealing body 4 is made of an elastic member such as rubber. After inserting the sealing body 4 into the opening of the exterior case 3, the exterior case 3 is formed into a sealed structure by performing a squeezing process on the side wall portion 3b and the opening end portion of the exterior case 3.

[0022] The sheet 5 is disposed between the inner surface of the bottom 3a of the exterior case 3 and the capacitor element 2. The sheet 5 is mainly composed of wool fibers and has electrical insulation properties. In this specification, that the main component of the sheet 5 is wool fibers means that the ratio of the weight of the wool fibers is the largest with respect to the total weight of the sheet 5. The sheet 5 may be composed only of wool fibers or may contain fibers other than wool fibers. More than half of the total weight of the sheet 5 may be the weight of the wool fibers. Preferably, the material of the sheet 5 is different from the material of the separator 23. The sheet 5 may be composed only of fibers and may not have a synthetic resin. The sheet 5 may be a felt sheet. The sheet 5 may be a felt sheet made of wool fibers or a felt sheet in which wool fibers and other fibers are mixed. The density of the sheet 5 is preferably less than 10mg / mm 3 It may be smaller than. The density of the sheet 5 may be smaller than 5mg / mm 3 and may even be smaller than 1mg / mm 3 as well.

[0023] The sheet 5 has flexibility. The sheet 5 has a circular shape, an elliptical shape, or a polygonal shape such as a quadrilateral or a hexagon. In FIG. 1, the sheet 5 is disposed in a state where the edge portion is bent, and when the sheet 5 is flattened, it is slightly larger than the bottom 3a of the exterior case 3. In FIG. 1, the size of the sheet 5 in the flattened state may be the same as the size of the inner surface of the bottom 3a of the exterior case 3. The size of the sheet 5 in the flattened state may be smaller than the size of the inner surface of the bottom 3a of the exterior case 3. However, in that case, the size of the sheet 5 in the flattened state is preferably the same as or larger than the size of the end face 2a of the capacitor element 2. Note that the end face 2a of the capacitor element 2 is the face of the capacitor element 2 that faces the inner surface of the bottom 3a of the exterior case 3.

[0024] In Figure 1, the thickness of sheet 5 is smaller than the size of the gap between the inner surface of the bottom 3a of the outer case 3 and the end face 2a of the capacitor element 2. The thickness of sheet 5 may also be the same as the size of this gap. Alternatively, the thickness of sheet 5 may be slightly larger than the size of this gap, and sheet 5 may be positioned in a compressed state in the thickness direction.

[0025] In Figure 1, sheet 5 is in contact with the end face 2a of capacitor element 2 due to gravity. However, depending on the orientation of the electrolytic capacitor 1 during use, sheet 5 may also be in contact with the inner surface of the bottom 3a of the outer casing 3 due to gravity. Sheet 5 is not fixed to either the capacitor element 2 or the inner surface of the outer casing 3. Alternatively, sheet 5 may be fixed to either the inner surface of the outer casing 3 or the capacitor element 2.

[0026] In this embodiment, the electrolytic capacitor 1 has an electrically insulating sheet 5, mainly composed of wool fibers, placed between the inner surface of the outer casing 3 and the capacitor element 2, thereby improving the sound quality reproduced in audio equipment using the electrolytic capacitor 1. Furthermore, because the sound quality is improved by the sheet 5 placed between the capacitor element 2 and the outer casing 3, it is possible to improve sound quality while ensuring freedom in selecting the material of the capacitor element 2 (i.e., freedom in selecting the separator 23, electrolyte and electrode foils 21, 22, etc.).

[0027] Furthermore, by positioning the sheet 5 between the inner surface of the bottom 3a of the outer case 3 and the capacitor element 2, it is possible to suppress the occurrence of a short circuit between the inner surface of the bottom 3a of the outer case 3 and the capacitor element 2, while further improving the sound quality reproduced in audio equipment using the electrolytic capacitor 1.

[0028] Next, we will describe some examples of modifications to the electrolytic capacitor 1 of the embodiment. Components with the same configuration as the electrolytic capacitor 1 are denoted by the same reference numerals and their descriptions are omitted.

[0029] The sheet 5 may not be placed between the inner surface of the bottom 3a of the outer case 3 and the capacitor element 2, but rather between the inner surface of the side wall 3b of the outer case 3 and the capacitor element 2. The sheet 5 may be placed between the inner surfaces of the bottom 3a and the side wall 3b of the outer case 3 and the capacitor element 2. In this case, the sheet 5 may be placed, for example, up to an intermediate position in the width direction of the separator 23, or it may be placed over the entire width direction of the separator 23. Both a sheet 5 placed between the inner surface of the bottom 3a of the outer case 3 and the capacitor element 2, and a sheet 5 placed between the inner surface of the side wall 3b of the outer case 3 and the capacitor element 2 may be provided.

[0030] In the above embodiment, an example of applying the electrolytic capacitor of the present invention to a chip-type electrolytic capacitor was described, but the application of the present invention is not limited to chip-type electrolytic capacitors. The electrolytic capacitor of the present invention may also be applied to substrate-free electrolytic capacitors or leaded electrolytic capacitors, etc. [Examples]

[0031] The present invention will be described in more detail below with reference to examples. Electrolytic capacitors of the examples and comparative examples were fabricated and acoustic evaluation tests were conducted.

[0032] For the electrolytic capacitors in Examples and Comparative Examples 1 and 2, a chip-type electrolytic capacitor 1 with a diameter of 6.3 mm, a height of 7.7 mm, a rated voltage of 35 V, and a capacitance of 47 μF was fabricated. In the Examples, a felt sheet made of wool fibers (i.e., a 100% wool fiber felt sheet) was placed between the inner surface of the bottom of the outer casing and the capacitor element. The felt sheet used was slightly larger than the inner surface of the bottom of the outer casing. The weight of the felt sheet was approximately 3 to 5 mg. The thickness of the felt sheet was approximately 0.2 to 0.4 mm, and the density of the felt sheet was approximately 0.3 to 0.5 mg / mm³. 3This is the extent of the difference. In Comparative Example 1, nothing was placed between the inner surface of the bottom of the outer casing and the capacitor element. In Comparative Example 2, absorbent cotton was placed between the inner surface of the bottom of the outer casing and the capacitor element. The density of the absorbent cotton was 0.3-0.5 mg / mm³. 3 It was set to a certain extent.

[0033] In the acoustic evaluation test, the electrolytic capacitors of the example and comparative examples 1 and 2 were used as output coupling capacitors in a CD player and listened to to evaluate the reproduced sound quality. Two listeners evaluated 10 items on a scale of 5 points each: clarity, depth, spaciousness, reverberation, power, extension, information content, reproducibility, resonance, and balance. The results are shown in Table 1 below. Note that the amount of information in the sound refers to the smoothness of the pitch.

[0034] [Table 1]

[0035] As can be seen from Table 1, the electrolytic capacitors in the example showed improved sound quality compared to the electrolytic capacitors in Comparative Examples 1 and 2.

[0036] Although the test results are omitted here, it was found that even when the density of the wool fiber sheet and the amount of wool fiber in the sheet were changed within the range where wool fiber is the main component, sound quality with excellent information density, reproducibility, and sustain was obtained.

[0037] In the above-described embodiment, we discussed the case where an electrolytic capacitor was used as an output coupling capacitor in a CD player. However, the invention is not limited to this, and good sound reproduction can also be achieved when applying electrolytic capacitors to applications such as power supply circuit filters, coupling and decoupling of various circuit blocks. [Explanation of symbols]

[0038] 1 Electrolytic capacitor 2 Capacitor elements 3. Outer case 3a bottom 4 Sealing body 5 sheets 21 Anode foil 22 Cathode Foil 23 Separator

Claims

1. Capacitor element and A bottomed cylindrical outer case for housing the capacitor element impregnated with electrolyte, A sealing body that seals the opening of the outer case, An electrolytic capacitor equipped with, An electrolytic capacitor characterized in that an electrically insulating sheet mainly composed of wool fibers is placed between the inner surface of the outer casing and the capacitor element.

2. The electrolytic capacitor according to claim 1, characterized in that the sheet is disposed between the inner surface of the bottom of the outer case and the capacitor element.

3. The electrolytic capacitor according to claim 1 or 2, characterized in that the sheet is a felt sheet made of wool fibers.

4. The capacitor element is formed by overlapping an anode foil and a cathode foil with a separator in between and winding them together. The electrolytic capacitor according to claim 1 or 2, characterized in that the sheet is made of a different material from the separator.

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