JP2599605Y2 - Trance - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION In the present invention, among transformers arranged on a printed circuit board, a coil made of a conductive pattern is arranged on the surface of the printed circuit board, and upper and lower cores are opposed from both sides of the printed circuit board. Related to a transformer mounted.

[0002]

2. Description of the Related Art Conventionally, a transformer in which a coil made of a conductive pattern is disposed on the surface of a printed circuit board, and upper and lower cores are mounted on the surface of the printed circuit board so that coils made of the conductive pattern face each other from both sides of the printed circuit board. Is configured, for example, as shown in FIG. That is, in FIG. 2, the transformer 1 includes a primary coil 3 and a secondary coil 4 formed of a conductive pattern formed in a threaded manner on both upper and lower surfaces of a printed circuit board 2, and in the area of these coils 3 and 4, The printed circuit board 2 includes an upper core 5 and a lower core 6 attached to the printed circuit board 2 so as to face each other.

The end of the primary coil 3 is connected to a connection lead pattern 7 extending leftward in the drawing, and the end of the secondary coil 4 is connected to a connection lead pattern 8 extending rightward in the drawing. It is connected.

In the upper core 5 of the transformer 1,
The thickness of the portion facing the primary coil 3 and the thickness of the portion of the lower core 6 facing the secondary coil 4 are uniform.

Accordingly, the distance between the upper core 5 and the upper surface of the printed circuit board 2 and the distance between the lower core 6 and the lower surface of the printed circuit board 2 are also constant and parallel.

[0006]

However, in the transformer 1 configured as described above, the leakage of the magnetic flux of the closed magnetic paths of the coils 3 and 4 is large, and the degree of coupling between the primary coil 3 and the secondary coil 4 is low. There was a problem that it was bad.

[0007] In view of the above, the present invention is to change the distance between the primary coil and the secondary coil and the portion of the upper and lower cores facing these two coils at least at the center and at the end. It is an object of the present invention to provide a transformer in which the leakage of a closed magnetic path of a coil is small and the degree of coupling between a primary coil and a secondary coil is improved.

[0008]

In order to achieve the above object, a transformer according to the present invention is provided on a surface of a printed circuit board.
In a transformer including two coils each formed of a conductive pattern formed in a spiral shape, and upper and lower cores attached to the printed board so as to face each other from both sides of the printed board in a region of the coil, The thickness of each of the upper and lower cores is gradually reduced from the center toward the end, and the distance between each of the upper and lower cores and the printed circuit board is changed.

[0009]

According to the above construction, the distance between the primary coil and the secondary coil and the portion of the upper and lower cores facing these two coils changes, thereby improving the degree of coupling between the primary coil and the secondary coil. be able to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of a transformer according to the present invention. In FIG. 1, the same reference numerals are given to portions corresponding to the respective portions of the conventional example shown in FIG.

The transformer 11 includes a primary coil 3 and a secondary coil 4 formed of a conductive pattern formed on both upper and lower surfaces of the printed circuit board 2 in a spiral manner. The upper core 15 and the lower core 16 are attached to the printed circuit board 2 so as to face each other.

An end of the primary coil 3 is connected to a connection lead pattern 7 extending leftward in the drawing, and an end of the secondary coil 4 is connected to a connection lead pattern 8 extending rightward in the drawing. Have been.

The thickness of a portion of the upper core 15 of the transformer 11 facing the primary coil 3 and the thickness of a portion of the lower core 16 facing the secondary coil 4 are center portions, respectively. The distance between the upper core 15 and the surface of the printed circuit board 2 on the primary coil 3 side and the lower core 16 are reduced by gradually reducing the size from A to the end B direction.
And the distance between the secondary coil 4 and the surface of the printed circuit board 2 is changed so that the central part A is the largest and the distance toward the end B is gradually reduced.

[0014]

As described above, according to the present invention, since the respective distances between the upper and lower cores and the surface of the printed circuit board are changed at least at the center and at the end, the upper and lower cores are different from the prior art. The magnetic flux density of the closed magnetic circuit of the coil is improved and the leakage of magnetic flux is reduced as compared with a case where the distance between the coil and the surface of the printed circuit board is constant and parallel. Therefore, there is an effect that the degree of coupling between the primary coil and the secondary coil is improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a transformer according to the present invention.

FIG. 2 is a schematic sectional view showing an example of a conventional transformer.

[Explanation of symbols]

 11 Transformer 2 Printed circuit board 3 Primary coil 4 Secondary coil 5, 15 Upper core 6, 16 Lower core 7, 8 Lead pattern A Central part B End part

Claims (1)

(57) [Scope of request for utility model registration] Claims: 1. A coil formed of a conductive pattern formed in a spiral shape on a surface of a printed circuit board, and in a region of the coil, opposed to both sides of the printed circuit board.
A transformer including upper and lower cores attached to the printed circuit board, wherein the thickness of each of the upper and lower cores facing the two coils is gradually reduced from the center toward the end; A transformer having a configuration in which the distance between each of the upper and lower cores and the printed circuit board is changed.