JPH08162745A - Fixing terminal structure of electronic device - Google Patents

Abstract

PURPOSE: To enhance reliability when an electronic device with a fixing terminal is surface mounted on a printed board by improving the shape of the fixing terminal, to be soldered by reflow to a printed circuit pattern on a printed board, such that the soldering face is widened and the bottom face is made narrower. CONSTITUTION: In a surface mount electronic device having a fixing terminal 3 to be soldered by reflow to a printed circuit pattern 5 on a printed board 4, the part of the fixing terminal 3 mounted on the printed circuit pattern 5 is beveled at the side edge part thereof thus providing a soldering surface 3c facing the pattern 5 while inclining against the bottom face 3b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component surface-mounted on a printed circuit board by reflow soldering a fixed terminal, and more particularly to a fixed terminal structure thereof.

[0002]

2. Description of the Related Art As this type of electronic component, one having an appearance as shown in FIGS.
In these figures, in the electronic component generally indicated by reference numeral 1, a fixed terminal 3 made of a thin metal plate is projected to the side of the main body 2, and the projecting shape is a crank shape in the case of FIG. However, in each case, as shown in FIG. 5, the tip portion of the fixed terminal 3 is mounted on a predetermined printed circuit pattern 5 of the printed circuit board 4 for reflow soldering, and solidified after melting. The fixed terminal 3 through the solder 6
The electronic component 1 is surface-mounted at a predetermined position on the printed circuit board 4 by electrically and mechanically connecting the printed circuit pattern 5 and the printed circuit pattern 5. The procedure of the reflow soldering is as follows. First, cream solder is applied on a predetermined printed circuit pattern 5, and the fixed terminals 3 of the electronic component 1 are mounted on the printed circuit pattern 5, and then in a reflow furnace. It is to heat and melt the cream solder.

[0003]

However, in the above-mentioned prior art, as shown in FIG. 5, the cross-sectional shape of the portion of the fixed terminal 3 mounted on the printed circuit pattern 5 is substantially rectangular, and its standing upright. Since only the side end surface 3a on which the solder 6 on the pattern 5 is attached is likely to be a soldering surface to which the solder 6 on the pattern 5 is attached, it is difficult to obtain sufficient soldering strength, so that the electronic component 1 after mounting may be peeled off from the printed board 4. there were.

Further, the fixed terminal 3 of the electronic component 1 of this type may be slightly deformed such that it is twisted at the time of transportation or assembly, but in the case of the conventional product, for example, the twist as shown in FIG. When the deformation occurs, one side in the width direction of the fixed terminal 3 floats largely on the printed circuit pattern 5 and does not function as a soldering surface. In such a case, the soldering strength of the fixed terminal 3 is extremely reduced. As a result, the electronic component 1 is likely to cause a peeling accident.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to fix an electronic component in which a soldering strength of a fixed terminal to be reflow-soldered is high and a peeling accident from a printed circuit board is unlikely to occur. It is to provide a terminal structure.

[0006]

The above-mentioned object of the present invention is to provide an electronic component for surface mounting comprising a fixed terminal which is mounted on a printed circuit pattern of a printed circuit board and is reflow-soldered. This is achieved by providing the side edge portion of the portion mounted on the printed circuit pattern with an inclined surface for soldering that is inclined with respect to the bottom surface and faces the printed circuit pattern.

Here, the soldering inclined surface may be formed by, for example, chamfering or bending the widthwise inner side of a side edge portion of a portion of the fixed terminal to be mounted on the printed circuit pattern. .

[0008]

If the fixed terminal of the electronic component is provided with the inclined surface for soldering, a relatively large solder pool having the inclined surface as a soldering surface is formed on the printed circuit pattern during reflow soldering. Thus, high soldering strength can be obtained. Further, since the bottom surface of the portion of the fixed terminal to be mounted on the printed circuit pattern becomes narrow, the soldering surface does not largely float on the pattern even when twist deformation occurs, and thus the soldering There is no concern that the attachment strength will drop extremely.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention, in which parts corresponding to those in FIGS. 3 to 5 described above are designated by the same reference numerals.

In FIG. 1, reference numeral 3 is a fixed terminal protruding laterally from a main body (not shown) of an electronic component, 4 is a printed circuit board on which the electronic component is surface-mounted, and 5 is formed on the printed circuit board 4. The printed circuit pattern 6 is a solder which is solidified after being melted in a reflow furnace (not shown). As shown in the figure, in this embodiment, the fixed terminal 3 is on the printed circuit pattern 5 of the printed circuit board 4. The shape of the part to be mounted on is different from the conventional product. That is, the fixed terminal 3 is chamfered at a side edge portion of a portion to be mounted on the printed circuit pattern 5, so that the side edge portion is inclined with respect to the bottom surface 3b and is inclined with respect to the pattern 5 for soldering. Since the surface 3c is provided, a relatively large solder pool having the inclined surface 3c as a soldering surface can be formed on the pattern 5 when reflow soldering is performed, and high soldering strength can be obtained. It has become. Further, since the bottom surface 3b of the fixed terminal 3 mounted on the printed circuit pattern 5 is narrowed by the chamfer, it is considered that the fixed terminal 3 is twisted and deformed during transportation or assembly. However, the inclined surface 3c for soldering does not largely float on the printed circuit pattern 5, that is, the inclined surface 3c hardly functions as a soldering surface, and the soldering strength is extremely reduced. I don't have to worry. Therefore, the electronic component provided with the fixed terminal 3 can always reflow solder the fixed terminal 3 to the printed circuit pattern 5 with sufficient soldering strength, and is unlikely to be peeled off from the printed circuit board 4 and is reliable. High surface mounting is possible.

FIG. 2 is a cross-sectional view of an essential part showing another embodiment of the present invention. Like FIG. 1, a cross-section of a portion of the fixed terminal 3 of the electronic component mounted on the printed circuit pattern 5 of the printed circuit board 4. The shape is shown.

That is, in the fixed terminal 3 shown in FIG. 2, the side edge portion of the portion mounted on the printed circuit pattern 5 is bent inward in the width direction, and the surface opposite to the bottom surface 3b has a substantially V shape. As a result, a soldering inclined surface 3c that is inclined with respect to the bottom surface 3b and faces the pattern 5 is provided at the side edge portion. As a result, in this embodiment, the fixed terminal 3 is formed with the inclined surface 3c for soldering, which has a larger area than that of the above-described embodiment. As a result, when the reflow soldering is performed, the inclined surface 3c is attached to the soldered surface. The solder pool is also larger than that in the above-mentioned embodiment, and higher soldering strength can be obtained.

[0014]

As described above, according to the present invention,
At the side edge of the fixed terminal to be reflow-soldered on the printed circuit pattern of the printed circuit board, which is mounted on the pattern, the inclined surface for soldering that is inclined with respect to the bottom surface and faces the pattern is provided. It is possible to form a relatively large solder puddle with the inclined surface serving as the soldering surface during reflow soldering, and high soldering strength can be obtained. There is no concern that the soldering surface will float significantly on the pattern, which will cause an extreme decrease in soldering strength, so that the fixed terminals can always be reflow-soldered with sufficient soldering strength, and An excellent electronic component capable of highly reliable surface mounting can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing another embodiment of the present invention.

FIG. 3 is a side view showing an example of a protruding shape of a fixed terminal in an electronic component.

FIG. 4 is a side view showing another example of the protruding shape of the fixed terminal in the electronic component.

FIG. 5 is a cross-sectional view showing a conventional fixed terminal soldered on a printed circuit pattern.

FIG. 6 is an explanatory diagram showing a problem of the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component 2 Main body 3 Fixed terminal 3b Bottom surface 3c Sloping surface for soldering 4 Printed circuit board 5 Printed circuit pattern 6 Solder

Claims (3)

[Claims] 1. An electronic component for surface mounting, comprising a fixed terminal which is mounted on a printed circuit pattern of a printed circuit board and is reflow soldered, comprising: a portion of the fixed terminal which is mounted on the printed circuit pattern. A fixed terminal structure for an electronic component, wherein an inclined surface for soldering, which is inclined with respect to a bottom surface and faces the printed circuit pattern, is provided on a side edge portion. 2. The electronic device according to claim 1, wherein the soldering inclined surface is formed by chamfering a side edge portion of a portion of the fixed terminal to be mounted on the printed circuit pattern. Fixed terminal structure for parts. 3. The soldering inclined surface according to claim 1, wherein a side edge portion of a portion of the fixed terminal mounted on the printed circuit pattern is bent inward in a width direction. Fixed terminal structure for electronic parts.