JPH082976Y2 - Line filter - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line filter for preventing power line noise of electronic equipment.

[0002]

2. Description of the Related Art Generally, a line filter is mainly used to prevent a common mode noise component generated between a pair of lines in a power supply line and ground, and its electric circuit is as shown in FIG. This is to prevent the magnetic flux generated by the line current from magnetically saturating the closed magnetic circuit core 4.
And 2 are arranged so as to cancel each other out of the magnetic flux generated by the line current.

As a concrete structure, as shown in FIGS. 5 and 6, a coil bobbin 3 made of a resin molding is provided with one winding 1 and another coil bobbin 3 is provided with the other winding 2, and these coil bobbins 3 are formed. The filter is mounted on the case 6, the UU type magnetic core 4 made of ferrite or the like is inserted into the coil bobbin 3 from both sides, and the outer peripheral portion of the UU type magnetic core 4 is fixed by a core band 5 made of a stainless metal plate or the like to form a line filter. The UU type magnetic core 4 including the core band 5 and the resin molded body such as the case 6 are fixed by means of adhesion 9, varnish impregnation 10 or the like.

[0004]

In manufacturing the line filter having the above-mentioned structure, the ferrite core used as the UU-type magnetic core 4 is a fired product and has a large dimensional tolerance because it is difficult to control the dimensions. Against this, looseness is likely to occur, and since it is weak against stress, it must be attached to the resin molded body such as the case 6 with great care. It was impregnated with varnish.

As a measure against the above problems, the present invention provides a line filter in which a UU type magnetic core and a resin molded body such as a case are fixed without adhering or impregnating a varnish and degrading the characteristics at a low cost.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides at both ends of an intermediate wall of a case, a deforming portion that abuts against the inner surface of a magnetic core and is deformed by tightening the magnetic core. The UU type magnetic core is sandwiched between the core band and the core band arranged on the outer periphery of the magnetic core to fix the UU type magnetic core to form a line filter.

[0007]

According to the above means, since the deformed portion is deformed by the amount tightened by the core band, the dimensional tolerance is covered and the UU is covered.
It is possible to fix the molded resin such as the mold core and case,
Moreover, since no extra stress is applied to the UU type magnetic core, characteristic deterioration does not occur. In addition, since the steps such as bonding and varnish impregnation can be omitted, cost reduction and high reliability are possible.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan sectional view showing an embodiment of a line filter according to the present invention, FIG. 2 is a perspective view showing an embodiment of a case according to the present invention, and FIG. 3 is an embodiment of the present invention. FIG.

An intermediate wall 17 of the case 16 as shown in FIG.
As shown in FIG. 3, the case 16 is provided with the deformed portions 18 that are deformed by the common magnetic legs of the UU type magnetic core 14 when the UU type magnetic core 14 is tightened with the core band 15 in the concave portions 19 for guiding the magnetic cores at both ends of the core. A coil bobbin 13 with a terminal arranged on one magnetic leg is provided with one winding 11, and a coil bobbin 13 with a terminal arranged on the other magnetic leg has the same number of turns as one winding. The other winding 12 with different winding directions
The UU type magnetic core 14 is inserted, and the core band 15 is attached to the outer periphery of the UU type magnetic core 14 to form a line filter.

In the above work, in the UU type magnetic core 14, the force clamped to the core band 15 deforms the deforming portion 18 provided in the case 16 through the common magnetic leg of the UU type magnetic core 14,
By being sandwiched between the deformed portion 18 and the core band 15 after deformation, there is no backlash after assembly, and means such as adhesion is unnecessary, which leads to prevention of characteristic deterioration and improvement of reliability test results.

The size of this deforming portion 18 is the UU type magnetic core 14.
Is larger than the maximum size within the dimensional tolerance of the intermediate wall 17 of the case 16 minus the minimum size within the dimensional tolerance of the intermediate wall 17, and the deformation limit size when deformed is the UU type magnetic core. It is designed to be smaller than a value obtained by subtracting the maximum size within the dimensional tolerance of the intermediate wall 17 of the case 16 from the minimum size within the dimensional tolerance of 14. In the present embodiment, the deformable portion 18 is provided as a thinner portion than when the case 16 is molded, but a cushioning material made of silicon rubber or the like may be attached after the case is molded. Further, the same effect can be obtained by providing the deformed portion on the end surface of the coil bobbin 13 as shown in FIG. 4 instead of the case 16.

[0012]

As described in detail above, the line filter according to the present invention has a structure in which the deformed portion is deformed by the amount tightened by the core band regardless of the dimensional tolerance of the magnetic core, so that the dimensional tolerance is covered. As a result, the UU-shaped magnetic core and the resin molded body such as the case can be fixed, and since no extra stress is applied to the UU-shaped magnetic core, characteristic deterioration does not occur. In addition, since it can be attached to the molded body itself, the steps of bonding, varnish impregnation, etc. can be omitted without increasing the new cost, which enables significant cost reduction and high reliability. Has an extremely large industrial effect.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing an embodiment of a line filter according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a case according to the present invention.

FIG. 3 is a perspective view showing an embodiment according to the present invention.

FIG. 4 is a perspective view of a coil bobbin of a line filter according to another embodiment of the present invention.

FIG. 5 is a plan sectional view for explaining a conventional example.

FIG. 6 is a plan sectional view for explaining another conventional example.

FIG. 7 shows an electric circuit diagram of a line filter.

[Explanation of symbols]

 11 One winding 12 The other winding 13 Coil bobbin 14 UU type magnetic core 15 Core band 16 Case 17 Intermediate wall 18 Deformation part 19 Recessed part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-151310 (JP, A) JP-A-2-146707 (JP, A) Actually opened 62-11111 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A coil bobbin having windings attached to opposite magnetic legs of a closed magnetic circuit core, and a case formed by a side plate for accommodating the coil bobbin and an intermediate wall is provided, and inner surfaces of the magnetic core are provided at both ends of the intermediate wall. A line filter which is provided with a deformable portion that comes into contact with the core and is deformed by tightening the magnetic core, and a core band is attached to the outer circumference of the closed magnetic circuit core.