JP2000340467A - Chip-type electrolytic capacitor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attach a seat plate to the capacitor main part of a chip-type electrolytic capacitor so as not to produce a useless space. SOLUTION: A chip-type electrolytic capacitor 10A has a metal case 31 whose element housing part 312 is a square cylinder with a square cross-section, whose sealing part 311 has a shape of a circle with a diameter of not longer than the length of one side of the square cross-section of the element housing part 312, and which has a peculiar shape. A square seat plate 40 which has a same shape and the same dimensions as the element housing part 312 is attached to the metal case 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type electrolytic capacitor in which a seat plate is mounted on a lead unidirectional type aluminum electrolytic capacitor. More specifically, the present invention does not waste space in mounting on a circuit board. The present invention relates to a chip type electrolytic capacitor and a method for manufacturing the same.

[0002]

2. Description of the Related Art Chip-type electrolytic capacitors can be classified into two types: a horizontal type and a vertical type. The horizontal type is configured by housing a capacitor body in a rectangular cylindrical case and bending its lead terminals along, for example, the side surface of the rectangular cylindrical case.

[0003] The vertical placement type is constructed by mounting a seat plate on the side of the sealing portion of the capacitor body and bending the lead terminals in a predetermined direction along the bottom surface of the seat plate. The present invention relates to a vertical type. First, a conventional example will be described with reference to a perspective view of FIG. 5 and a cross-sectional view of FIG.

The chip type electrolytic capacitor 10 includes a capacitor body 11 and a seat plate 21. The capacitor body 11 has a metal case 12 made of aluminum or the like, in which a capacitor element 13 is housed. In this case, the metal case 12 is formed in a bottomed cylindrical shape.

The capacitor element 13 is formed by winding a pair of electrode foils made of aluminum through a separator in a cylindrical shape, and lead terminals 14 and 15 are attached to each electrode foil. The opening of the metal case 12 is sealed by a rubber sealing body 16 made of, for example, butyl rubber, and the lead terminals 14 and 15 pass through the sealing body 16 and are drawn out.

The seat plate 21 is made of a heat-resistant synthetic resin, and is attached to the end face of the capacitor body 11 on the side of the sealing portion. A pair of lead insertion holes 22 and 23 are formed in the seat plate 21, and the respective lead terminals 14 and 15 are drawn out to the bottom side of the seat plate 21 through the lead insertion holes 22 and 23, and the respective tip portions 14 a thereof are provided. , 15a are bent away from each other. It should be noted that two adjacent corners of the seat plate 21 are provided with tapers 21a, 21a for polarity display.

According to this, the capacitor body 11 is placed on a circuit board (not shown) via the seat plate 21 in a self-standing state (vertically placed state), and is soldered by a reflow soldering method.

[0008]

In the chip-type electrolytic capacitor 10, the role of the seat plate 21 is not only to achieve the electrical insulation between the metal case 12 of the capacitor body 11 and the circuit board, but also to play the main role. The purpose is to obtain stability during mounting. For this purpose, it is preferable that the seat plate 21 is larger than the condenser main body 11.

In view of the above, conventionally, the seat plate 21 is formed into a quadrangle having one side of the diameter of the capacitor body 11 (more precisely, a deformed hexagon due to the presence of the taper 21a for indicating the polarity). However, the above prior art has the following problems.

In other words, regardless of whether the seat plate 21 is rectangular or modified hexagonal, the projected area when viewed from directly above the capacitor body 11 indicates that the Since the board 21 is a larger square (square or modified hexagon), each corner of the seat plate 21 becomes a useless space when viewed from the circuit board on which the board 21 is mounted. Will be a hindrance.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to make the most of a limited mounting area on a circuit board to reduce a capacitance. It is an object of the present invention to provide a chip-type electrolytic capacitor capable of obtaining a larger capacitance with respect to a mounting area and a method of manufacturing the same.

In order to achieve the above object, the present invention provides a bottomed cylindrical metal case in which a capacitor element formed by winding a pair of electrode foils via a separator is accommodated, and the opening of the metal case is made of rubber. A pair of lead terminals which are sealed by a sealing body and have a pair of lead terminals connected to the capacitor element and are pulled out through the rubber sealing body and are drawn in the same direction, and a sealing portion of the capacitor body. And a seat plate made of a heat-resistant synthetic resin mounted on the side, wherein each of the lead terminals extends through the seat plate to the bottom side, and is bent in a direction away from each other along the bottom surface. In the chip type electrolytic capacitor, the element housing portion in the metal case is
The cross section orthogonal to the winding axis of the capacitor element is formed in a substantially square rectangular tube shape, and the sealing portion of the metal case has a diameter equal to or shorter than one side of the square. It is characterized by being formed in.

According to this structure, the projected area of the element storage portion with respect to the circuit board matches the projected area of the seat plate.
No wasted space is created. This means that the volume of the element storage portion can be increased to a portion that has been wasted in the past, and accordingly, the capacitance can be increased accordingly.

[0014] Also, if speaking relatively, the same capacitance as that of the related art is sufficient, so that the size can be reduced accordingly. Since the sealing portion is circular, the sealing operation can be performed in the same manner as in the related art.

According to a preferred embodiment of the present invention, the capacitor element is also formed in a rectangular tube shape whose cross section orthogonal to the winding axis is substantially square, and the seat plate is also a square plate having substantially the same shape as the element housing portion. It is formed in a shape.

According to the present invention, a chip-type electrolytic capacitor is manufactured as follows. First, a metal plate made of aluminum or the like is deep drawn, and a bottomed cylindrical shape having an element housing portion formed of a rectangular cylindrical body having a substantially square cross section and a circular opening having a diagonal diameter of the rectangular cylindrical body. To form a metal case.

A capacitor element having a pair of lead terminals is accommodated in the element accommodating portion, and a rubber sealing member having a pair of lead insertion holes is inserted into the opening of the metal case while each lead terminal is inserted through the lead insertion hole. Fits.

The peripheral surface of the opening of the metal case is laterally drawn, and the diameter of the opening is reduced to a circle having the same length as or shorter than one side of the element housing portion to obtain a capacitor body.

A seat plate having a pair of lead insertion holes, which is substantially the same shape as the element accommodating portion and has a pair of lead insertion holes, is inserted into the end face of the capacitor body on the rubber sealing body side while each lead terminal is inserted through the lead insertion holes. After the attachment, each end of the lead terminal is bent in a direction away from each other.

In the present invention, a rectangular cylindrical capacitor element is preferably used. To obtain a rectangular cylindrical capacitor element, a pair of electrode foils are wound into a cylindrical shape with a separator interposed therebetween, and then the element storage is performed. Although it is preferable to deform the rectangular tube into a square tube having substantially the same shape as the part, another method is to wind a pair of electrode foils around a prism core via a separator to form a square tube having substantially the same shape as the element housing portion. May be obtained.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to an embodiment shown in the drawings. FIG. 1 is a perspective view of a chip-type electrolytic capacitor 10A according to this embodiment. According to this, the chip-type electrolytic capacitor 10A includes a capacitor body 30 and a seat plate 40 attached to the capacitor body 30. Its basic components.

FIG. 2 is an exploded perspective view of the capacitor main body 30. For convenience of explanation, the capacitor main body 30 is inverted from FIG. The capacitor body 30 includes a metal case 31 made of, for example, aluminum, a capacitor element 33 housed in the metal case 31, and a rubber sealing body 35 for closing an opening of the metal case 31.

The metal case 31 is formed of a bottomed tubular body (a tubular body having a bottom at one end and an open end at the other end). Here, assuming that a portion sealed by the rubber sealing body 35 is an opening (sealing portion) 311 and a portion where the capacitor element 33 is actually stored is an element housing portion 312, the opening 31
Although 1 is circular, the element storage portion 312 is formed in a rectangular tube shape.

FIGS. 3 (a) to 3 (c) are a plan view, a side view and a bottom view, respectively, for easy understanding of the shape of the metal case 31. In this embodiment, the element housing portion 312 is formed in a square cylindrical shape having a square cross section orthogonal to the axis of the cylindrical body (the axis of the capacitor element 33).

On the other hand, the opening 311 is a perfect circle whose diameter is the diagonal line R of the element housing 312. The metal case 31 having such a shape is obtained by deep drawing a metal plate having good spreadability such as aluminum.

The capacitor element 33 is obtained by spirally winding a pair of electrode foils made of aluminum with a separator interposed therebetween. In this embodiment, the capacitor element 33 is traversed in accordance with the element housing 312. The surface is formed in the shape of a square with a square shape.

In order to make the capacitor element 33 into a rectangular tube shape,
After winding as a cylindrical body, it may be deformed into a rectangular tube by pressing or the like. Alternatively, the electrode foil may be wound around a prism core to form a rectangular tube. In any case, lead terminals (tab terminals) 331 and 332 are provided on each electrode foil before winding.
Is attached.

The rubber sealing member 35 is made of, for example, a disk of butyl rubber, and includes a pair of lead insertion holes 351 and 35.
2 are drilled. The rubber sealing member 35 is attached to the lead terminals 331 and 332 of the capacitor element 33 and, together with the capacitor element 33,
Put in one.

Thereafter, the opening 311 of the metal case 31 is squeezed and sealed by a horizontal drawing machine (not shown). FIG. 4 is a plan view showing a state after narrowing down.
In this case, the diameter of the opening 311 is reduced to a circular shape inscribed in the square shown by the element housing portion 312 as shown by a chain line in the drawing.

That is, the opening 311 is narrowed down to a circle having a diameter of one side of a regular square by horizontal drawing.
If there is still room for narrowing down to metal, it may be narrowed down to a smaller diameter.

As a result, the rubber sealing body 35 is compressed in the radial direction, and the opening 311 is hermetically sealed (FIG. 6).
reference). The primitive diameter of the rubber sealing body 35 is appropriately determined from the relationship with the narrowing amount.

A seat plate 40 is attached to the sealing body side of the capacitor body 30 thus manufactured. The seat plate 40 is made of a heat-resistant synthetic resin, and is basically a quadrangle as in the above-described conventional example, and two adjacent corners are provided with polarity display tapers 401 and 401.

Therefore, to be precise, although the seat plate 40 is a deformed hexagon, the taper 401 for polarity display is not necessarily required, and the description will be continued here assuming that the seat plate 40 is a quadrangle.

As shown in the plan view of FIG. 4, the size of the seat plate 40 is set to be within the projected area of the element housing portion 312. In this embodiment, the seat plate 40 has the same size as the element storage section 312.

Although not shown, the seat plate 40 is provided with a pair of lead insertion holes as in the conventional example described above, and the capacitor body 30 is inserted through the lead insertion holes.
The lead terminals 331 and 332 are pulled out to the bottom surface side of the seat plate 40, and their respective tips are bent in directions away from each other (see FIG. 6).

Each of the lead terminals 331 and 332 is a CP.
It is originally a round bar made of wire (copper-coated steel wire).
Prior to mounting or after mounting of the seat plate 40, it is crushed flat by a press and processed into a strip shape.

According to the chip-type electrolytic capacitor 10A, the projected area of the element housing portion 312 with respect to the circuit board is:
Since the projected area of the seat plate 40 with respect to the circuit board is the same, there is no useless space, and the circuit board surface can be used effectively.

Incidentally, assuming that the capacitor body is a conventional cylindrical type and the diameter is 8 mm, the projected area is 5 mm.
Although it is 0.24 mm ² , in the case of the conventional example, since the side of the seat plate is 8 mm, the projected area of the seat plate (the area occupied by the circuit board) is 64 mm ² .

Therefore, although about 30% of the space is wasted, according to the present invention, the portion of the wasted space is effectively utilized, so that the element can be stored if the size of the seat plate is not changed. The volume of the portion is increased by about 30%, and the capacitance is increased accordingly. On the other hand, if the capacitance is not changed, the area occupied by the circuit board can be reduced by about 30%.

Although the present invention has been described with reference to the specific embodiments, those skilled in the art will recognize that the present invention can be applied to equivalent variations and modifications.
Modifications will be readily apparent. Therefore, the scope of the present invention extends not only to the invention described in the claims but also to equivalent technologies.

[0041]

As described above, according to the present invention,
By using a metal case of a unique shape in which the element storage part is a square cylinder with a square cross section and the sealing part is a circle with a diameter equal to or shorter than one side of the square, As a result, a chip-type electrolytic capacitor that does not cause useless space is obtained.

That is, it is possible to increase the volume of the element storage portion up to a portion that has been wasted conventionally, and therefore it is possible to increase the capacitance accordingly. Also, speaking relatively, if the same capacitance as that of the related art is sufficient, the size can be reduced accordingly. Since the sealing portion is circular, the sealing operation can be performed in the same manner as in the related art.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a chip type electrolytic capacitor according to the present invention.

FIG. 2 is an exploded perspective view of a capacitor body used in the embodiment.

FIG. 3 is a plan view, a side view, and a bottom view of a metal case used in the capacitor body.

FIG. 4 is a plan view of the embodiment.

FIG. 5 is a perspective view showing a chip-type electrolytic capacitor as a conventional example.

FIG. 6 is a sectional view of the conventional example.

[Explanation of symbols]

 10A Chip type electrolytic capacitor 30 Capacitor main body 31 Metal case 311 Opening (sealing part) 312 Element storage part 33 Capacitor element 331, 332 Lead terminal 35 Rubber sealing body 351, 352 Lead insertion hole 40 Seat plate 401 Polarity display taper

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[Procedure amendment]

[Submission date] June 1, 1999 (1999.6.1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

Claims (6)

[Claims] 1. A capacitor element formed by winding a pair of electrode foils via a separator in a bottomed cylindrical metal case, and an opening of the metal case is sealed with a rubber sealing body. A pair of lead terminals connected to the capacitor element are pulled out through the rubber sealing body, and the lead terminals are drawn in the same direction, and a heat-resistant synthetic resin mounted on the sealing body side of the capacitor body. Wherein each of the lead terminals extends through the seat plate to the bottom surface side and is bent in a direction away from each other along the bottom surface. The element housing portion of the case has a cross section orthogonal to the winding axis of the capacitor element formed in a substantially square rectangular tube shape, The sealing portion of the nest,
A chip-type electrolytic capacitor formed in a circular shape having a diameter equal to or shorter than one side of the square. 2. The chip-type electrolytic capacitor according to claim 1, wherein the capacitor element has a cross section orthogonal to the winding axis, and is formed in a substantially square prism shape. 3. The chip-type electrolytic capacitor according to claim 1, wherein said seat plate is also formed in the shape of a regular square plate having substantially the same shape as said element housing portion. 4. A metal plate made of aluminum or the like is deep-drawn to have an element storage portion formed of a rectangular cylinder having a substantially square cross section and a circular opening having a diameter diagonal to the rectangular cylinder. A bottom cylindrical metal case is formed, a capacitor element having a pair of lead terminals mounted therein is housed in the element housing portion, and a rubber sealing body having a pair of lead insertion holes is provided with the respective lead terminals in the lead insertion holes. After being fitted into the opening of the metal case while passing through, the peripheral surface of the opening of the metal case is subjected to horizontal drawing, and the diameter of the opening is equal to or equal to one side of the element housing portion. A capacitor body is obtained by reducing the capacitor body to a shorter circular shape, and a seat plate having a pair of lead insertion holes, which is formed in a square plate shape having substantially the same shape as the element housing portion, is provided on an end surface of the capacitor body on the rubber sealing body side. Lead insertion A method of manufacturing a chip-type electrolytic capacitor, comprising: mounting each lead terminal while inserting the lead terminal into the through hole; and bending each tip end side of the lead terminal in a direction away from each other. 5. The capacitor element is a rectangular cylindrical capacitor element obtained by winding a pair of electrode foils into a cylindrical shape with a separator interposed therebetween, and then deforming the same into a regular square cylinder having substantially the same shape as the element housing portion. The method for manufacturing a chip-type electrolytic capacitor according to claim 4, wherein: 6. The capacitor element is a rectangular cylindrical capacitor element formed by winding a pair of electrode foils around a prism core via a separator, and formed in a regular square cylinder having substantially the same shape as the element housing portion. The method for manufacturing a chip-type electrolytic capacitor according to claim 4, wherein: