JP2727950B2 - Chip type electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electrolytic capacitor, and more particularly to a chip type electrolytic capacitor suitable for surface mounting on a substrate.

[0002]

2. Description of the Related Art Conventionally, in order to realize a chip of an electrolytic capacitor, the capacitor element is subjected to resin molding,
A lead wire for external connection led out from a resin end face is bent along a resin side face to face a wiring pattern of a printed circuit board.

[0003] Alternatively, as disclosed in Japanese Utility Model Publication No. 59-3557, for example, a conventional electrolytic capacitor is housed in an outer frame, and a lead wire is arranged substantially flush with an end face of the outer frame. Proposed. Also, JP-A-60-245116 and JP-A-60-2451.
As in the invention described in Japanese Patent Publication No. 15, an electrolytic capacitor is arranged on a bottomed cylindrical exterior frame, and a lead wire is led out from a through hole on the bottom surface of the exterior frame, and this lead wire is attached to the outer surface of the exterior frame. One that is bent so as to be accommodated in a provided recess is proposed.

[0004]

However, in a chip type electrolytic capacitor subjected to molding, there is a risk that the capacitor element may be thermally degraded due to thermal stress during molding. Also, as shown in FIG.
When the chip type electrolytic capacitor 30 having the lead wire 3 drawn out from the end surface of the outer frame 2 and facing the printed circuit board 12 is soldered 11, the chip type electrolytic capacitor 30 is soldered 11. Only one end of the chip-type electrolytic capacitor 30 is fixed to the printed board 12. Therefore, the other end may be lifted by the heat of the solder, or may be separated from the printed circuit board 12 by a mechanical stress.

[0005] Further, with the recent miniaturization of electronic components, the distance between lead wires derived from the electronic components has become extremely short, and this dimension has become finer. Furthermore, the wiring pattern density of a printed circuit board has also increased, and the distance between various lead wires has been required for efficient placement. Therefore, it is necessary to secure an appropriate distance between the lead wires, that is, a distance that does not cause a short circuit due to solder, and to hold the lead wires so as to correspond to the distance between various lead wires. Has become.

Further, the leading end of the lead wire facing the bottom surface of the exterior frame has a "burr" due to a so-called elastic force.
It was difficult to restore the original shape and maintain an appropriate position and distance.

An object of the present invention is to provide a chip type electrolytic capacitor which can realize a good mounting state on a printed circuit board without changing the structure of a general electrolytic capacitor.

[0008]

According to the present invention, an electrolytic capacitor is housed in an outer frame having a housing space adapted to the outer diameter of the electrolytic capacitor, and a lead wire led out from the same end face of the electrolytic capacitor is connected to an opening of the outer frame. The present invention is characterized in that a conductive paste that can be soldered is applied to a part of the bottom surface and the end surface that is bent along the end surface and the bottom surface and does not contact the lead wire.

[0009]

As shown in the drawing, on the bottom surface of the outer frame 2, a lead wire 3 led out of the electrolytic capacitor 1 and a solderable conductive paste 8 are arranged. Then, when mounted on a printed circuit board, both ends of the bottom surface of the chip type electrolytic capacitor 21 are fixed to the printed circuit board by soldering by soldering the lead wire 3 and the conductive paste 8 respectively.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a chip type electrolytic capacitor according to an embodiment of the present invention as viewed from a bottom surface direction of an outer frame.

The main body of the electrolytic capacitor 1 is formed by housing a capacitor element formed by winding an electrode foil (not shown) and electrolytic paper (not shown) in a bottomed cylindrical outer case made of aluminum or the like. As shown in FIG. 1, the opening end of the outer case is sealed with a sealing body 4, and a lead wire 3 led from a capacitor element is passed through the sealing body 4 and drawn out.

The main body of the electrolytic capacitor 1 is accommodated in an outer frame 2 having a cylindrical accommodating space which is adapted to the outer diameter and outer shape of the electrolytic capacitor 1. It is desired that the exterior frame 2 be made of a material having excellent heat resistance, and preferably, a heat-resistant synthetic resin such as epoxy, phenol, or polyimide having excellent heat resistance, or a ceramic material is suitable.

In this embodiment, the housing space of the outer frame 2 is formed in a cylindrical shape having an inner diameter substantially equal to the outer diameter of the electrolytic capacitor 1 because the electrolytic capacitor 1 having a cylindrical outer shape is used in this embodiment. ing. When a non-cylindrical electrolytic capacitor, for example, an electrolytic capacitor having an elliptical cross-sectional shape is used, an outer frame having an elliptical cylindrical storage space adapted to the shape is used.

The lead wire 3 led out from the end face of the electrolytic capacitor 1 is bent along the open end face and the bottom face of the exterior frame 2 and is housed in a groove 6 provided on the bottom face of the exterior frame 2. A lead wire 3 is provided on the bottom surface of the exterior frame 2.
The conductive paste 8 is previously applied to a position where the conductive paste 8 does not come into contact.

The conductive paste 8 is made of a solderable metal, for example, a metal powder of silver, tin, lead, zinc, nickel, iron, copper or the like, a mixed powder thereof, or a metal powder of an alloy thereof. Generated by mixing with synthetic resin. The synthetic resin mixed with the metal powder may be of any kind, but a thermosetting synthetic resin having excellent heat resistance, for example, epoxy, phenol, diallyl phthalate, unsaturated polyester, polyimide, polyamide imide, polyamide Bismaleimide and the like are preferred.

A projection 5 is provided on one of the end surfaces of the exterior frame 2 to cover a part of the opening. This projection 5
Is the electrolytic capacitor 1 stored in the storage space of the outer frame 2
Abuts the end face of Accordingly, the main body of the electrolytic capacitor 1 is fixed in the exterior frame 2 by the projections 5 and the bent lead wires 3.

In this embodiment, a lead wire 3 led out of the electrolytic capacitor 1 main body and a conductive paste 8 applied in advance are arranged on the bottom surface of the exterior frame 2. Therefore, when the chip-type electrolytic capacitor 21 according to the present embodiment is mounted on a printed circuit board, the lead wire 3 and the conductive paste 8 are soldered respectively to form the chip-type electrolytic capacitor 21.
Are fixed to the printed circuit board.

Further, compared with a case where a solderable metal plate or the like is arranged using an adhesive, it is not necessary to use an adhesive, and a member which can be soldered to the bottom surface of the outer frame 2 can be easily formed. can do. For this reason, there is no danger of the adhesive being thermally changed or peeled off due to solder heat in the soldering process.

In the above embodiment, the lead wire 3
In the bending process, a flat portion may be provided in a part of the lead wire 3 and the lead wire 3 may be bent based on the flat portion, and in this case, the bending process is facilitated.

[0020]

As described above, according to the present invention, the electrolytic capacitor is housed in the outer frame having a housing space suitable for the outer diameter of the electrolytic capacitor, and the lead wire led out from the same end face of the electrolytic capacitor is connected to the opening of the outer frame. It is characterized by applying a conductive paste that can be soldered to the bottom surface and a part of the end surface that does not come into contact with the lead wire while being bent along the end surface and the bottom surface. Is soldered to the printed circuit board at both ends of the bottom surface of the outer frame.

Therefore, it is possible to prevent the chip-type electrolytic capacitor mounted on the printed circuit board from being lifted up or separated from the printed circuit board due to vibration, solder heat, "burring" of the lead wire, and the like as in the prior art. In addition, it becomes stronger against mechanical stress when mounted on a printed circuit board, and can maintain a proper mounting state, thereby improving reliability.

An extremely thin conductive paste is formed on a part of the bottom surface of the outer case. Therefore, a stable mounting state can be maintained without deteriorating the stability of the chip-type electrolytic capacitor according to the present invention, and since it is not mounted obliquely in the mounting process,
It can be transported and mounted in the same manner as electronic components used for normal surface mounting.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a chip-type electrolytic capacitor according to an embodiment of the present invention from a bottom surface direction of an outer frame.

FIG. 2 is a front view showing a state in which a conventional chip-type electrolytic capacitor is mounted on a printed circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolytic capacitor 2 Outer frame 3 Lead wire 4 Sealing body 5 Projection part 6 Groove part 8 Conductive paste 11 Solder 12 Printed circuit board

Claims (1)

(57) [Claims] 1. An electrolytic capacitor is housed in an exterior frame having a storage space adapted to the external shape of the electrolytic capacitor, and a lead wire derived from the same end surface of the electrolytic capacitor is bent along the open end surface and the bottom surface of the exterior frame. In addition, a chip type electrolytic capacitor in which a solderable conductive paste is applied to a part of a bottom surface and an end surface which does not contact a lead wire.