JP2687293B2 - Chip type capacitor and manufacturing method thereof - Google Patents

Description

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

[Conventional technology]

Conventionally, in order to realize a capacitor chip, the capacitor element was subjected to resin molding, the lead wire for external connection derived from the resin end face was bent along the resin side face, and faced the wiring pattern of the printed board .

Alternatively, for example, as in the invention described in Japanese Utility Model Publication No. 59-3557, a capacitor in which a conventional capacitor is housed in an exterior frame and lead wires are arranged on substantially the same plane as an end surface of the exterior frame has been proposed. . Further, as in the inventions described in JP-A-60-245116 and JP-A-60-245115,
A capacitor has been proposed in which a capacitor is placed in a bottomed cylindrical outer frame, a lead wire is derived from a through hole in the bottom surface of the outer frame, and the lead wire is bent so as to be accommodated in a concave portion provided on the outer surface of the outer frame. ing.

[Problems to be solved by the invention]

However, in a chip-type capacitor subjected to molding, the capacitor element may be thermally degraded due to thermal stress at the time of molding, and many parts are structurally different from conventional capacitors, and the manufacturing method is complicated.

In addition, when soldering an electronic component, the soldering temperature is basically limited by the heat-resistant temperature of the outer frame made of synthetic resin or the like. For example, the heat resistant temperature (heat distortion temperature) of phenol resin is about 200 ° C. Therefore, when the phenol resin is molded into the outer frame, the soldering temperature of about 200 ° C. becomes the upper limit.

However, the tensile strength of the solder itself generally decreases as the temperature rises. Along with this, the strength of the solder joint is also reduced. Therefore, when the soldering seam is exposed to an environment of a high temperature region, it is necessary to use a solder that can withstand higher temperatures. Therefore, the soldering condition should be 240 ℃ ～ 2
It is said that it is preferable to use solder of about 60 ° C.

However, as described above, when soldering is performed in a temperature range above this range, that is, at a preferred soldering temperature of around 250 ° C, to a chip-type capacitor that uses an outer frame that has heat resistance of around 200 ° C. In some cases, the outer frame is partially softened and melted, which causes inconvenience such as poor appearance and makes it difficult to form a capacitor chip.

An object of the present invention is to realize a chip-type capacitor that can be operated and used in a high temperature range.

[Means for solving the problem]

This invention has a storage space that conforms to the external shape of the capacitor, stores the capacitor in an outer frame in which a cylinder is arranged on the inner surface of the storage space, and opens the lead wire led out from the end surface of the capacitor into the outer frame. It is characterized by being bent along the end face and the bottom face.

As another means, on the inner surface of the storage space of the exterior frame,
It is characterized in that a tubular body made of metal or synthetic resin having a higher thermal conductivity than that of the exterior frame is arranged.

Then, there is a manufacturing method in which an outer frame having a storage space is primarily formed in a low temperature range, a cylinder is placed in the storage space, and a heat treatment is further performed for secondary molding, and a capacitor is stored in the cylinder. , In this manufacturing method,
The outer frame is characterized by being made of thermoplastic synthetic resin.

(Operation)

The solder heat in the soldering process is conducted from the exterior frame 2 shown in the drawing to the cylindrical body 8 having high thermal conductivity. Therefore, the rise in the surface temperature of the outer frame 2 becomes slower, and the soldering temperature can be set higher than the heat-resistant temperature of the outer frame 2 made of synthetic resin.

In the experiment, even when the soldering temperature was set to about 10 ° C. higher than the heat-resistant temperature of the outer frame 2, the outer shape of the outer frame 2 did not change.

If there is a gap between the exterior frame 2 and the tubular body 8, heat conduction in this gap becomes slower than that in other portions.
When the heat distribution becomes unbalanced in this way, the temperature of the blunt part of heat conduction becomes higher than that of the other part, and the exterior frame 2 partially melts,
It may be deformed.

However, when the cylindrical body 8 is housed in the outer casing 2 that has been primarily formed in a low temperature range and then heat-treated to be secondarily formed, crystallization of the outer casing 2 in a low crystalline state proceeds. for that reason,
The outer frame 2 is housed and comes into close contact with the tubular body 8, so that the solder heat is uniformly conducted to the tubular body 8. As a result, the temperature distribution in the soldering process becomes uniform, and the partial melting and deformation of the outer frame 2 can be prevented.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a chip type capacitor according to the embodiment of the present invention. FIG. 3 is a partial sectional view showing a second embodiment of the present invention.

The capacitor 1 main body accommodates a capacitor element formed by winding an electrode foil (not shown) and electrolytic paper in a bottomed cylindrical outer case made of aluminum or the like, and a sealing body 4 is attached to the outer case opening. Tighten the open end of the outer case to seal it. Lead wire 3 led from the capacitor element
Are pierced through the sealing body 4 and drawn out to the outside.

The exterior frame 2 is preferably made of a thermoplastic synthetic resin having excellent heat resistance, such as polyimide, polyamide-imide, or polyphenylene oxide. In this example, primary molding was performed in the low temperature region of polyimide to form the exterior frame 2 having the storage space 7 inside.

Next, as shown in FIG. 2, the storage space 7 of the exterior frame 2
The cylindrical tubular body 8 made of aluminum or the like, which has a size corresponding to, is accommodated. After that, the exterior frame 2 is heat-treated again to promote crystallization of the synthetic resin. As a result, the outer frame 2 contracts, and the outer frame 2 and the cylindrical body 8 come into close contact with each other. Next, the capacitor 1 is stored in the storage space 7 (cylindrical body 8) of the exterior frame 2.

Since the storage space 7 and the cylindrical body 8 of the exterior frame 2 use the capacitor 1 having a cylindrical outer shape in this embodiment, they are formed into a cylindrical shape having an inner diameter dimension that matches the outer diameter dimension of the capacitor 1. Has been done. When using a non-cylindrical capacitor, for example, a capacitor having an elliptical cross-sectional shape, an outer frame and a tubular body having an elliptic cylindrical storage space adapted to the shape are used.

In addition, a projection 5 that covers a part of the opening is provided on one of the end surfaces of the exterior frame 2. The protruding portion 5 contacts one end surface of the capacitor 1 housed in the housing space 7 of the exterior frame 2. Therefore, the main body of the capacitor 1 is fixed in the exterior frame 2 by the protrusion 5 and the lead wire 3.

The lead wire 3 projecting from the capacitor 1 housed in the outer frame 2 has the outer frame 2 in the vicinity of the tip portion and the central portion thereof.
It is bent along the opening end face and the bottom face and is housed in the notch 6 of the exterior frame 2 to obtain the chip type capacitor as shown in FIG.

In the case of this embodiment, there is almost no gap on the contact surface between the housing space 7 of the outer frame 2 and the cylindrical body 8 due to the contraction of the outer frame 2 due to the secondary molding. Therefore, thermal stress such as solder heat is evenly distributed on the outer surface of the outer frame 2 to prevent partial melting, deformation, and the like. Also, due to the secondary contraction, the cylindrical body 8
Is firmly fixed to the storage space 7 of the outer frame 2, so that a highly reliable chip-type capacitor having excellent mechanical strength can be obtained.

Next, a second embodiment of the present invention shown in FIG. 3 will be described.

In the second embodiment, as in the first embodiment, the main body of the capacitor 1 is formed by accommodating the capacitor element in the outer case and attaching the sealing body to the opening of the outer case. Further, the exterior frame 2 is also the same as in the first embodiment.
It is made of heat-resistant synthetic resin and has a storage space inside.

A cylindrical body 9 made of a synthetic resin having a higher thermal conductivity than that of the synthetic resin forming the outer frame 2 is housed in the housing space of the outer frame 2. Then, the main body of the capacitor 1 is housed in the cylindrical body 9. Lead wire 3 protruding from the end face of capacitor 1
Is bent along the opening end face and the bottom face of the exterior frame 2 as in the first embodiment.

In the case of this embodiment, the adhesion between the tubular body 9 and the body of the capacitor 1 is excellent, and the mounted state of the capacitor 1 in the storage space (cylindrical body 9) of the exterior frame 2 becomes good.

In any of the above embodiments, when bending the lead wire 3, if the bent portion of the lead wire 3 is processed into a flat shape in advance, the bending work becomes easy.

〔The invention's effect〕

As described above, the present invention has a storage space that conforms to the external shape of a capacitor, stores the capacitor in an outer frame in which a cylinder is arranged on the inner side surface of the storage space, and connects the lead wire derived from the end face of the capacitor. It is characterized by being bent along the opening end surface and the bottom surface of the exterior frame.

As another means, on the inner surface of the storage space of the exterior frame,
Since the cylindrical body made of metal or a synthetic resin having a higher thermal conductivity than the outer frame is arranged, the solder heat is conducted from the outer frame to the cylindrical body. Therefore, the temperature of the outer frame is lower than the actual soldering temperature,
It becomes possible to solder in a temperature range higher than the heat resistant temperature of the synthetic resin forming the outer frame. Accordingly, it is possible to use a solder having a high melting temperature, and the soldering portion in a high operating temperature environment has a good fixation state, thereby improving reliability.

Then, after the outer frame having the storage space is primarily molded in a low temperature range, the cylinder is placed in the storage space, and further heat-treated to carry out the secondary molding, and the capacitor is housed in the cylinder. Due to the shrinkage of the outer frame due to the secondary molding, the space between the housing space of the outer frame and the cylindrical body is reduced.

Therefore, when the chip type capacitor according to the present invention is mounted on a printed circuit board and subjected to soldering, the solder heat is evenly conducted to the cylindrical body, and the temperature distribution on the outer surface of the outer frame becomes uniform. As a result, partial deformation and melting of the exterior frame can be prevented, and inconveniences such as poor appearance are reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a chip type capacitor according to the embodiment of the present invention. FIG. 3 is a partial sectional view showing a second embodiment of the present invention. 1 ... Capacitor, 2 ... Exterior frame, 3 ... Lead wire, 4 ... Sealing body, 5 ... Projection part, 6 ... Notch part, 7 ... Storage space, 8,9 ... Cylindrical body.

Claims (5)

(57) [Claims] 1. A capacitor having a storage space adapted to the external shape of the capacitor, the capacitor being housed in an outer frame in which a cylindrical body is arranged on the inner surface of the storage space, and the lead wire led out from the end face of the capacitor being used for the outer frame. A chip type capacitor characterized by being bent along the opening end face and the bottom face. 2. The chip type capacitor according to claim 1, wherein a cylindrical body made of metal is arranged on the inner surface of the storage space of the outer frame. 3. The chip type capacitor according to claim 1, wherein a cylindrical body made of synthetic resin having a higher thermal conductivity than that of the outer frame is arranged on the inner surface of the housing space of the outer frame. 4. A primary molding of an exterior frame having a storage space in a low temperature range, a cylindrical body is disposed in the storage space, a heat treatment is further performed to perform secondary molding, and a condenser is stored in the cylindrical body. And a method for manufacturing a chip-type capacitor. 5. The method of manufacturing a chip capacitor according to claim 4, wherein a thermoplastic synthetic resin is used for the outer frame.