JP2588916Y2 - Choke coil for noise filter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a choke coil for a noise filter mounted on an electronic device for suppressing electromagnetic noise.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional noise filter inserted in a power supply line has normal mode choke coils 2a and 2b inserted in series with power supply lines 3 and 4, and a single power supply line annular. It is a combination of a common mode choke coil 1a whose winding is wound in such a direction that magnetic fluxes generated in the magnetic core by a reciprocating current flowing through a power supply line in the magnetic core cancel each other. That the number of mechanical parts increases,
There are drawbacks such as an increase in the occupied area on the printed circuit board to be mounted.

[0003]

In order to solve these problems, the present invention disposes a frame-shaped annular closed magnetic path core having a high relative magnetic permeability characteristic on the outer periphery, and connects a power line to each of the opposed magnetic legs. Due to the magnetic flux generated by the reciprocating current, the magnetic flux generated in the annular closed magnetic path core is wound in a direction to cancel each other, and two metal magnetic powders having high relative permeability characteristics are provided inside the frame-shaped annular closed magnetic path core. Each of the power supply wires is wound around each of the dust cores formed in a shape, and two normal mode choke coils are arranged. The two normal mode chokes are sized to be housed inside the common mode choke coil. Connect one line of the mode choke coil and the common mode choke coil, and the other of them in series, integrally mold the case with resin, and attach it to the case when mounting the board The pin terminals and to provide only in the normal mode choke coil 2 and the common mode choke coil 1 noise choke coil filter for the noise filter formed connected to the power supply line on the substrate.

[0004]

Means for Solving the Problems An annular closed magnetic path core having a high relative magnetic permeability characteristic is arranged on the outer periphery, and two dust cores made of a metal magnetic powder having a frame shape are accommodated therein. Each of the dust cores is wound with a parallel power supply wire to form a no-marque coil, and the outer peripheral frame-shaped annular closed magnetic core is magnetized so that the magnetic fields generated by the reciprocating power supply currents cancel each other out. A power supply line is wound around each leg to form a common mode choke coil. The normal mode choke coil is placed inside the common mode choke coil on both sides of the partition separating the two central normal mode choke coils, and the common mode choke coil and the normal mode choke coil are pinned on the board mounting surface. Place the terminal in the case where it was planted, connect the lead wires to each pin terminal and solder it,
The common mode choke coil and the normal mode choke coil are filled with embedded resin and fixed integrally. Accordingly, the noise filter choke coil can easily form a noise filter on the substrate simply by connecting a capacitor and a fixed resistor to the pin terminals, respectively.

That is, according to the present invention, the same number of windings are wound around the magnetic legs on both sides of the annular closed magnetic core in a frame shape having a high relative permeability characteristic on the outer periphery, and two power supply lines are respectively differentially wound. A common mode choke coil, and a normal mode choke coil in which each of two power supply wires is wound around two powder magnetic cores that fit inside the common mode choke coil,
One of the windings of the common mode choke coil and one of the normal mode choke coils, and the other winding of the common mode choke coil and the other of the normal mode choke coil are connected in series, respectively, on the lower surface of the board mounting surface. A choke coil for a noise filter, wherein the choke coil is housed in a case to which pin terminals are attached and filled with resin.

[0006]

[Function] The arrangement and winding of one common mode choke coil and two normal mode choke coils are arranged at symmetrical positions, and each choke coil has a close contact structure. Has a small effect. In addition, since pin terminals are provided between the input and output sides of the normal mode choke coil and the common mode choke coil and between the normal mode choke coil and the common mode choke coil, only a capacitor or a fixed resistor is connected to the pin terminal. A noise filter in which two types of filters of type, π-type, or inverted L-type are cascaded can be easily configured.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A noise filter choke coil according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a magnetic core and a winding of a choke coil for a noise filter according to the present invention. The choke coil for a noise filter of the present invention is a set of choke coils including normal mode choke coils 2a and 2b connected in series to two lines of a power supply line and a common mode choke coil 1 connected in series to a power supply line. Body. On the outer periphery, an annular closed magnetic core 1c of normal Mn-Zn ferrite having a high initial relative permeability or a Ni-Zn ferrite core having a high specific magnetic permeability having a high initial relative permeability is used. Is provided with a frame-shaped dust core 2c made of metal magnetic powder of the same material and the same size, or a magnetic core having a gap in a magnetic path of a ferrite core.
In the dust core 2c, each winding of the power supply line is wound around the magnetic path to form normal mode choke coils 2a and 2b. A power line through which a reciprocating current flows is wound around the annular closed magnetic circuit core 1c by the required number of turns around the magnetic legs on both sides, and the magnetic field generated by the winding is wound differentially in a direction to cancel each other to form the common mode choke coil 1. Then, the windings of the normal mode choke coil 2a on the input side lines of the power supply lines 3 and 4 are connected in series with one winding of the common mode choke coil 1, respectively.
The winding of the other normal mode choke coil 2b is connected to the other winding of the common mode choke coil 1. After the two normal mode choke coils 2a and 2b and one common mode choke coil 1 shown in FIG. 1 are wound, they are housed in a case 5 shown in FIG. 2 and a power supply line is provided between the two normal mode choke coils. A partition plate 6 for ensuring the electrical insulation characteristics between them is inserted, and the whole surface of the wound choke coil is injected and impregnated with a resin and fixed. As shown in FIG. 3, on the lower surface of the case 5, on the input / output side of the power supply line, pin terminals 11a are attached to the pin terminals 11a and 11b, and also to the power supply line between the normal mode choke coil and the common mode choke coil. . Depending on the configuration of the capacitor and fixed resistor connected to the pin terminal, T-type, π-type, reverse L
The noise filter choke coil of the present invention can form a cascade connection circuit of the noise filter. In addition, each magnetic core is coated with an electric insulating coating on the surface when winding the winding, or a coil bobbin with a structure that can be incorporated into the magnetic legs divided horizontally in the magnetic leg direction is incorporated into the magnetic legs, and the magnetic core and The winding of the choke coil is wound while ensuring the electrical withstand voltage characteristics between the winding and the winding.

[0008]

According to the present invention, according to the present invention, two powder magnetic cores are housed inside the annular closed magnetic core of the frame-shaped annular closed magnetic core, and the normal mode choke coil is formed by winding the winding around the powder magnetic core. A power supply line is wound around an annular closed magnetic circuit core in a differential manner to form a common mode choke coil, and one common mode choke coil and two normal mode choke coils are formed. The pin terminal is pulled out from the middle of the coil and the common mode choke coil, and it can be mounted on the board. Also, by using a choke coil for a noise filter that is housed in a case and integrally molded with resin, three conventional choke coils can be used. An inexpensive noise filter chose that reduces the board mounting area occupied by each and reduces the number of components when each choke coil is used. Choke coil it can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing an arrangement of a choke coil for a noise filter according to the present invention.

FIG. 2 is an external perspective view of a noise filter choke coil according to the present invention before the choke coil is housed in a case and subjected to resin molding.

FIG. 3 is a pin terminal arrangement diagram on the substrate mounting side.

FIG. 4 is a diagram showing an arrangement of a noise filter, a normal mode choke coil, and a common mode choke coil.

[Explanation of symbols]

 1, 1a Common mode choke coil 1c Annular closed magnetic path core 2, 2a, 2b Normal mode choke coil 2c Dust core 3, 4 Power line 5 Case 6 Partition plate 7, 8 Flange 9, 10 Winding 11a, 11b, 11c Pin Terminal

Claims (1)

(57) [Scope of request for utility model registration] 1. A common mode choke in which two power lines are wound differentially on each side of a circular closed magnetic circuit core having the same number of windings on both side magnetic legs of a frame shape having a high relative magnetic permeability characteristic on the outer periphery. A coil and a normal mode choke coil in which one of the two power supply wires is wound around two dust cores that fit inside the common mode choke coil, and one of the windings of the common mode choke coil. One of the normal mode choke coils, the other winding of the common mode choke coil and the other of the normal mode choke coil are connected in series, respectively, and placed in a case having pin terminals attached to the lower surface of the substrate mounting surface. A choke coil for a noise filter characterized by being filled.