JPH0580126B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a sealed transformer that is used as a small pulse transformer for use in video cameras, telephones, etc. and is required to be surface-mountable. It is related to.

BACKGROUND OF THE INVENTION In recent years, various electronic devices such as video cameras and telephones have made remarkable progress, and as sets become smaller and lighter, efforts are being made to use chip parts for surface mounting and high-density mounting. In response to this trend in assembly, there is an increasing demand for surface mounting of all types of components.

In order to meet these market demands, case-type sealed transformers with excellent safety are being adopted.

This hermetic transformer is shown in FIGS. 4 to 6. FIG. 4 shows a cross-sectional view of a conventional hermetic transformer. A winding 7 is performed on the coil bobbin 1 which has a collar 5 at both ends and an enlarged part formed in a part of the collar 5 to serve as a terminal part 2. At this time, the lead wire of the winding 7 is wired to the wiring terminal 4. do. Next, after winding on coil bobbin 1,
A magnetic core 6 made of a magnetic material such as a ferrite core is inserted into the coil bobbin 1 to assemble the magnetic core, which is then inserted into a protective case 8, and then a bottom plate 10 is inserted into the opening of the protective case 8 to complete the process. This protective case 8 is provided with ribs 9, and a bottom plate 10.
A step 11 is provided on the outer periphery of the protective case 8, and during assembly, the bottom plate 10 enters while pushing the opening of the protective case 8 outward, and returns to its original position after the step 11 passes through the rib 9. In this way, since the bottom plate 10 is inside the protective case 8, the design was such that both the protective case 8 and the bottom plate 10 come into contact with the board when mounting the transformer on the board.

FIG. 5 shows a perspective view of a conventional hermetic transformer. Further, FIG. 6 shows a side view of a conventional closed type transformer. In this way, in the structure of the conventional sealed transformer, due to the precision of parts and assembly, the protective case 8
A gap T was created between the bottom surface of the base plate 10 and the bottom surface of the bottom plate 10.

Problems to be Solved by the Invention In the conventional closed type transformer, the protective case 8 and the bottom plate 10 can be fitted together by simply pushing the bottom plate 10, which has a step 11, into a rib 9 provided on the circumference of the opening of the protective case 8. Therefore, it is difficult to fix the protective case 8 and the bottom plate 10, and gaps occur between the bottom surface of the external terminal 3, the bottom surface of the protective case 8, and the bottom surface of the bottom plate 10, among the three components. When this sealed transformer is mounted on a printed circuit board, gaps may be created between the terminals of the printed circuit board and the transformer, or between the printed circuit board and the bottom plate, resulting in poor soldering of the terminals, poor adhesion between the printed circuit board and the transformer, etc. reliability,
There were stability issues.

The present invention aims to eliminate the above-mentioned conventional drawbacks and provide a sealed transformer suitable for surface mounting in which the protective case is configured to rest on the bottom plate and the bottom surface of the bottom plate is used as a reference surface during mounting.

Means for Solving the Problems In order to solve the above problems, the present invention has a structure in which the protective case is completely positioned on the bottom plate and the bottom surface of the bottom plate is used as a reference surface for surface mounting, and a recess is formed on the inner surface of the protective case. In addition, a convex portion is provided on a part of the bottom plate, and the convex portion is connected to the concave portion of the protective case by fitting thereto.

Effect As described above, in the present invention, by positioning the protective case on the bottom plate and using the bottom surface of the bottom plate as the reference surface for mounting, it is easy to make the bottom surface of the terminals of the transformer body and the bottom surface of the bottom plate flush with each other. This makes it possible to provide a sealed transformer that can be surface-mounted with high precision and stability.

Embodiment An embodiment of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a sectional view of a sealed transformer according to the present invention. A winding 14 is attached to a coil bobbin 13 having a flange 11 at both ends and a terminal portion 12 having an enlarged portion formed in a part of the flange 11 and having an external terminal 21 and a wiring terminal 22.
The lead wire of this winding 14 is connected to the wiring terminal 22.
wired to. A magnetic core 1 made of a magnetic material such as an EI type such as a ferrite core is attached to a coil bobbin 13 that is wound.
5 and assemble the transformer body, the transformer body is inserted into the protective case 16, and the bottom plate 17 is fitted and fixed with the protective case 16. At this time, the opening of the protective case 16 is smaller than the size of the bottom plate 17, so that the protective case 16 is placed on the bottom plate 17. Therefore, only the bottom plate 17 and the external terminals 21 come into contact with the board when mounted on the board. For fitting, a recess 18 is provided near the opening on the inner surface of the protective case 16, a protrusion 19 is provided on the bottom plate 17, and a protrusion 20 is provided on the top of the protrusion 19. It has a structure that is fitted and coupled to the recess 18.

FIG. 2 shows a perspective view of the hermetic transformer of the present invention. The protective case 16 is constructed to rest on a bottom plate 17.

FIG. 3 shows a side view of the hermetic transformer of the present invention. Since the protective case 16 and the bottom plate 17 are completely fitted together and the transformer body is also placed on the bottom plate 17, it is possible to have a structure in which the external terminals 21 and the bottom surface of the bottom plate 17 completely match.

Effects of the Invention As explained above, the present invention has a structure in which the protective case is located on the bottom plate, and the fitting between the protective case and the bottom plate is a concave and convex fitting structure.
Since the transformer body is supported by the bottom plate, the bottom of the bottom plate and the bottom of the external terminals can be aligned, making it possible to surface-mount them onto the printed circuit board with great precision, eliminating terminal floating defects and poor adhesion during mounting. It becomes possible to improve such problems.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the hermetic transformer of the present invention, Fig. 2 is a perspective view of the hermetic transformer, Fig. 3 is a side view of the same, and Fig. 4 is a cross section of a conventional hermetic transformer. FIG. 5 shows a perspective view of the same sealed transformer, and FIG. 6 shows a side view of the same. 11... Tsuba, 12... Terminal section, 13... Coil bobbin, 14... Winding wire, 15... Magnetic core, 16...
Protective case, 17... Bottom plate, 18... Recess, 19
... protrusion, 20 ... protrusion, 21 ... external terminal,
22... Wiring terminal.

Claims (1)

[Claims] 1. A transformer body comprising a coil bobbin with flanges at both ends, an enlarged portion formed in a part of the flanges to form a terminal portion, and a coil bobbin with a terminal inserted into the terminal portion, and a magnetic core incorporated in the coil bobbin. , a protective case with a recess near the opening on the inner surface into which the transformer body is inserted, and a protrusion that fits into the recess of the protective case, the size of which is the same as or larger than the opening of the protective case. A sealed transformer that consists of a bottom plate whose bottom surface serves as a reference surface for surface mounting, and external terminals of the terminals of the transformer body whose bottom surfaces are flush with the bottom surface of this bottom plate.