JPH0462164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a line filter used to remove noise from power lines of electronic devices and the like.

Conventional configuration and its problems Conventional line filters are shown in Figures 1 to 3.
As shown in the figure, they can be roughly classified into three types.

First, the one shown in Fig. 1 has an insulating case or insulating paint 2 applied around the outer periphery of a round, integrally pressure-molded toroidal ferrite core 1, and a conductor 3 having an insulating coating wound thereon by a specified number of turns. be.

This configuration requires a very difficult winding method and is usually done manually. Further, even if an automatic winding machine is used, the price of the automatic winding machine is very high, and therefore the product price also becomes very high.

Next, in the case shown in FIG. 2, two U-shaped ferrite cores 4 are inserted into an insulating bobbin 5 around which a conductor 6 having an insulating coating is wound.
is fixed with a spring fitting 7 or an adhesive 8. U-shaped ferrite core 4
In some cases, an EE type or EI type ferrite core is used as a substitute.

Although this configuration is effective in terms of construction because the winding method and assembly work are simple, a closed magnetic circuit is constructed by joining two ferrite cores 4 together, but it has the following drawbacks. There is.

(1) In order to suppress variations in inductance, it is necessary to polish the joint surfaces of the ferrite cores 4 with high precision, which increases the cost of polishing.

(2) Compared to a toroidal ferrite core, the inductance efficiency with respect to the number of turns of the conductor 6 is lower.

(3) Magnetic flux tends to leak from the joint surface of the ferrite core 4, which adversely affects peripheral components on the circuit such as printed circuit boards.

Further, in the case shown in FIG. 3, an insulating bobbin 11 divided into two parts is pasted together with an adhesive 13 or the like to a square-shaped integrally press-molded wellite core 10, and a gear 11' provided on the insulating bobbin 11 is connected from the outside. It is formed by meshing driving gears and winding a conductor 12. In some cases, an insulating plate 14 equipped with terminals 15 is attached when attached to a printed circuit board or the like.

In the case of this configuration, the above-mentioned drawbacks such as polishing of the ferrite core and leakage of magnetic flux are eliminated, but since the magnetic path of the ferrite core 10 is only on one side of the wound conductor 12, as shown in FIG. Compared to the structure using the round toroidal ferrite core 1, this structure has the drawbacks that leakage magnetic flux increases and the inductance efficiency decreases with respect to the number of turns of the conductor 12.

Purpose of the Invention The present invention eliminates the above-mentioned drawbacks, and provides a line that minimizes leakage magnetic flux, improves the efficiency of inductance with respect to the number of turns of a conductor, and is easy to manufacture, inexpensive, and highly reliable. The purpose is to provide a filter.

Structure of the Invention In order to achieve this object, the present invention involves integrally press-forming a ferrite core into a Japanese-shaped shape and sintering it, and forming two or more winding grooves in the central magnetic leg of the ferrite core. A gear is provided on the brim and an insulating bobbin divided into two pieces is combined, and the insulating bobbin is rotated using the gear on the brim of the combined insulating bobbin to provide a winding terminal for external connection and the ferrite core. A ferrite core having a winding is attached to an insulating plate provided with an insulating protruding plate located between the conductor and the conductor.

With this configuration, the magnetic path of the ferrite core is formed on both outsides of the wound conductor, so the leakage magnetic flux is only in the axial direction of the wound conductor, which reduces the influence on the outside and reduces the leakage magnetic flux. As the magnetic flux density of the ferrite core decreases, the efficiency of inductance with respect to the number of turns of the conductor also increases. Furthermore, the wire winding method also allows the use of mechanical equipment, making it easier to manufacture. Furthermore, since the ferrite core and the conductor are insulated by the insulating protrusion plate, safety is high.

DESCRIPTION OF EMBODIMENTS An embodiment of the line filter of the present invention will be described below with reference to FIGS. 4 and 5. Note that FIG. 4 is a plan view, and FIG. 5 is a front view.

In the above figure, 21 is a ferrite core that is integrally press-formed in the shape of a Japanese character and then sintered.The central magnetic leg 21' is divided into two pieces, and an insulating bobbin 22 with a gear on the brim is combined with the ferrite core. Insulating bobbin 22
The combined surfaces 23 of are fixed by adhesive or fitting connection. The inner core of this combined insulating bobbin 22 is provided with a circular hole 29 circumscribing the central magnetic leg 21' of the ferrite core 21, and the outer circumference of the brim is smaller than the inner side of the outer circumferential magnetic leg of the ferrite core 21. It is a polygon equivalent to that. In order to obtain the required inductance, a plurality of external drive gears are engaged with the gear 28 provided on the collar of the insulating bobbin 22 incorporated in the ferrite core 21, and the conductor 2 having the insulating film is rotated by the gear 28 provided on the collar of the insulating bobbin 22 incorporated in the ferrite core 21.
7 is wound a specified number of times to form a winding.

The function of obtaining inductance as a line filter is configured as described above, but in order to attach it to an external printed circuit board, etc., an insulating plate 25 as shown in the figure is attached, and an external connection terminal 24 provided on the insulating plate 25 is attached. Then, both terminal leads of the wound conductor 27 are wound and connected by soldering or the like. At this time, an insulating protrusion plate 26 is formed on the insulating plate 25, and the insulating protrusion plate 26 is made to protrude between the conductor 27 and the ferrite core 21 and is used for insulation protection. In addition, this insulating protruding plate 26 is shaped to abut against the inner surface of the ferrite core 21, and also serves to position the ferrite core 21, thereby improving ease of assembly. Furthermore, when considering safety, conductor 27 and ferrite core 2 should be further covered with an insulating case.
1 may be covered.

Effects of the Invention As described above, in the present invention, since only one ferrite core is used, there is no seam between the ferrite cores as in the conventional example where two ferrite cores are used, and the polishing work thereof is no longer necessary. In addition, since the ferrite core has a sun-shaped shape, the magnetic path is formed on both outsides of the wound conductor, and the leakage magnetic flux is only in the axial direction of the conductor, which reduces the magnetic influence on the outside and reduces the magnetic influence of the ferrite core. The magnetic flux density increases and the efficiency of inductance with respect to the number of turns of the conductor also improves.

Therefore, according to the present invention, equipment such as an automatic winding machine can be applied to the construction method, making manufacturing easier, and since the magnetic influence on the outside is reduced, handling in the equipment used is also easier. Furthermore, it has the advantages of electrical performance as mentioned above, and when obtaining the same inductance as the conventional example, the volume and weight of the ferrite core can be reduced, which reduces the product cost, and an insulating plate is used between the ferrite core and the conductor. Because of the presence of the insulating protruding plate, it is possible to improve the insulation between the two, and the ferrite core can be positioned reliably on the insulating plate, making it easier to assemble, making it highly valuable industrially.

[Brief explanation of the drawing]

1 to 3 are front views showing a conventional line filter, FIG. 4 is a plan view showing an embodiment of the line filter of the present invention, and FIG. 5 is a front view thereof. 21... Ferrite core, 21'... Central magnetic leg,
22... Insulating bobbin, 23... Joint between two bobbins, 24... External connection terminal, 25... Insulating plate, 26... Insulating projection plate, 27... Conductor, 28...
…gear.

Claims (1)

[Claims] 1 The central magnetic leg of a Japanese-shaped ferrite core that has been integrally pressure-formed and sintered is equipped with two or more winding grooves and a gear on its brim, and an insulating bobbin divided into two is combined, and the A conductor having an insulating coating is wound in the winding groove of the assembled insulating bobbin by rotating the insulating bobbin using a gear on the collar, and an external connection terminal is provided and a wire is inserted between the ferrite core and the conductor. A line filter consisting of a ferrite core with a winding attached to an insulating plate provided with an insulating protrusion plate.