JP3429818B2 - Ferrite core and bobbin - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrite core for a thin transformer used in an inverter or the like and a bobbin thereof.

[0002]

2. Description of the Related Art Conventionally, this type of thin transformer ferrite core has a structure as shown in FIGS. 4 and 5, and since the coil is exposed from the lower surface of the core like the coil winding portion 11, a magnetic flux is generated. It was liable to leak and was a drawback that deteriorated the characteristics of the transformer. Further, the bobbin terminal conventionally has a structure having a coil lead-out terminal pin 13 and a board mounting terminal pin 14 at both ends of a collar as shown in FIG. In addition, since the structure is inconvenient, it has been a cause of limiting the core design.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the structure of a ferrite core and a bobbin in order to eliminate these drawbacks, and an object thereof is to provide a thin transformer having a small leakage flux.

[0004]

According to a first aspect of the present invention, a yoke, a middle leg having a flat cross section extending from the yoke, and a plurality of outer leg upper portions extending from the yoke and surrounding the middle leg are provided. The lower foot of the outer foot has a flat cross section, the major axis of the cross section is substantially parallel to the major axis of the cross section of the middle foot, and shorter than the major axis, and wherein the outer and central feet of the cross section with the center of the cross section of the metatarsal, a ferrite core positioned perpendicular collinear substantially long axis of the cross section of the metatarsal, the From the middle foot and the middle foot
It is possible to wind around the inside foot that is regulated inside the outside foot.
The effective area is the area formed by connecting the outside of the outer leg with a straight line.
It is a ferrite core characterized in that it is configured to be inside . A second invention is a bobbin that combines the above ferrite cores and arranges and mounts the inside foot and the outside foot on the inside and the outside of a tubular winding core that winds a coil on the outer periphery,
At both ends of the winding core, a flange for partitioning the ferrite core and the coil is provided, and on the outer circumference of the winding core between the flanges,
The bobbin is characterized in that a collar for partitioning the coil is provided, and a terminal pin is provided at a position of the collar corresponding to a groove formed between an outer foot lower portion and an outer foot upper portion of the ferrite core.

[0005]

[Function] In the ferrite core, cutout grooves for drawing out the end of the coil are provided on the left and right sides of the lower surface of the ferrite core,
In addition, the coil lower surface is also surrounded by the core, and for the bobbin, the position and shape of the bobbin terminal pin are changed to prevent the coil from being exposed on the lower surface of the core.
The leakage flux of the thin transformer can be reduced.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a structure of a ferrite core according to the present invention. FIG. 1A is a plan view.
1B is a front view, and FIG. 1C is a side view. The core is composed of a middle foot 3, an outer foot lower portion 1, an outer foot upper portion 4, a core lower cutout groove 2 for drawing out a coil, and a core upper cutout groove 5. FIG. 2 is a perspective view when the ferrite cores of FIG. 1 are combined in pairs.

FIG. 3 is a perspective view of a bobbin according to the present invention. A coil lead wire stripping terminal pin 8 and a board mounting terminal pin 9 are provided on the lower left and right sides of the core partition collar 6 and the coil partition collar 7 at both ends of the bobbin. The coil lead-out wire stripping terminal pin 8 and the board mounting terminal pin 9 are integrated. The coil winding terminal is connected to the coil lead-out wire stripping terminal pin 8, and the board mounting terminal pin 9 is printed. It has a structure that can be surface-mounted on a board. The structure is such that the coil lead-out terminal pin 8 and the board mounting terminal pin 9 provided under the core partition flange 6 and the coil partition flange 7 at both ends of the bobbin are exposed from the core lower cutout groove when the transformer is assembled. Has become.

In the conventional thin core, the coil is exposed from the lower surface of the core as in the coil winding portion 11 of FIGS. 4 and 5, but in the present invention, the lower surface of the coil is formed by the lower portion of the outer foot of FIG. It has a structure surrounded by, and also the core lower cutout groove 2
The structure is such that the coil is not exposed from the end face. Thereby, the leakage magnetic flux can be reduced.

Further, the core upper surface cutout groove 5 of FIG. 1 is used for wiring a thick wire that cannot be wired to the terminal of the bobbin, and may be omitted if not used.

As for the cross-sectional area of the core, it is an efficient method to make the middle foot and the outer foot have the same area.
Since there are two locations of 2 and three locations of the outer foot lower portion 1 and the outer foot upper portion 4 of FIG. 1, there is also an advantage that the outer circumference of the core can be made small even with the same area.

The structure of the bobbin is as shown in FIG.
By providing the coil lead-out terminal pin 8 and the board mounting terminal pin 9 not only on the core partition flanges 6 at both ends of the bobbin but also on the coil partition flanges 7, a plurality of coils can be wired. There is. In addition, the board mounting terminal pin 9 has a bent structure for surface mounting, but is not bent for being an insert type.
It goes without saying that it can be straight. Further, the coil lead wire pin-breaking terminal pin 8 has a structure slightly protruding from the lower surface of the core, whereby the height of the entire transformer can be suppressed. Further, the core upper cutout groove cover portion 10 in the bobbin is more advantageous in terms of withstand voltage when provided in the case of a high-voltage transformer, and may be omitted if not provided otherwise.

The present invention has many coil terminals such as a cold cathode inverter transformer and can be applied to a transformer or the like which requires a thin type.

[0013]

As described above, according to the present invention, it is possible to provide a ferrite core and a bobbin which have the advantages of low leakage flux and high efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a ferrite core according to the present invention.
1A is a plan view, FIG. 1B is a front view, and FIG.
Is a side view.

FIG. 2 is a perspective view when the ferrite cores of FIG. 1 are combined in pairs.

FIG. 3 is an external perspective view of a bobbin according to the present invention.

FIG. 4 is a diagram showing a structure of a conventional ferrite core. Figure 4
4A is a plan view and FIG. 4B is a front view.

FIG. 5 is a diagram showing a structure of a conventional ferrite core. Figure 5
5A is a plan view and FIG. 5B is a front view.

FIG. 6 is an external perspective view of a conventional bobbin.

[Explanation of symbols] 1 Lower foot 2 Core lower cutout groove 3 middle legs 4 Upper foot 5 Core notch groove 6-core partition tsuba 7 coil partition tsuba 8,13 Coil lead wire terminal pin for barking 9,14 PCB mounting terminal pins 10 Core notch groove cover 11 coil winding part 12 foot

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Claims (2)

(57) [Claims] 1. A yoke and a flat leg whose cross section extends from the yoke, and an outer leg that extends from the yoke and surrounds the middle leg. The lower part of the outer foot has a flat cross section, and the long axis of the cross section is substantially parallel to the long axis of the cross section of the middle foot, and is shorter than the long axis of the cross section of the middle foot. The center of the cross section of the middle foot and the center of the cross section of the middle foot are ferrite cores located substantially on the same straight line perpendicular to the long axis of the cross section of the middle foot, and the middle foot and the outside viewed from the middle foot. Regulated inside the foot
The area where winding to the middle foot is possible is the outside of the outer foot.
A ferrite core characterized in that it is configured so that it is within a region formed by connecting with a straight line . 2. A bobbin which is formed by combining the ferrite cores according to claim 1 and arranging and mounting the inner foot and the outer foot inside and outside a cylindrical winding core around which a coil is wound. A flange for partitioning the ferrite core and the coil is provided at both ends of the core, and a flange for partitioning the coil is provided on the outer periphery of the winding core between the flanges, and the flange is provided with an outer lower part of the ferrite core and an outer part of the ferrite core. A bobbin characterized in that a terminal pin is provided at a position corresponding to a groove formed between the upper part of the foot.