JP2000021658A - Line filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a line filter which can remove both common-mode noise and normal-mode noise at the same time. SOLUTION: A 2nd noise removal means, which removes a normal-mode noise applies magnetic flux A and a magnetic flux B generated by one winding 3 and the other winding 4 to a closed magnetic path core 5 in mutually opposite directions so that they cancel each other and also applies the magnetic flux A and magnetic flux B to the center in the collar part 6 of a bobbin 2 in the same direction so as to remove them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line filter for removing common mode noise and normal mode noise used in various consumer appliances and the like.

[0002]

2. Description of the Related Art A conventional line filter will be described below with reference to the drawings.

FIG. 11 is a perspective view of a conventional line filter.
12 is a front cross-sectional view of the line filter, FIG. 13 is an electric circuit diagram showing propagation of common mode noise when the line filter is used, and FIG. 14 is a magnetic field showing a flow of magnetic flux caused by common mode noise of the line filter. It is a circuit diagram.

Referring to FIGS. 11 and 12, a conventional line filter includes a bobbin 22 having a through hole 21 and one winding 23 and the other winding 24 wound around the bobbin 22.
And a closed magnetic circuit core 25 inserted into the through hole 21 of the bobbin 22.
And

In FIGS. 13 and 14, noise removing means for removing the common mode noise 26 is provided, and the noise removing means includes a magnetic flux A generated from one winding 23 and the other winding 24, respectively. , So that the magnetic fluxes B are in the same direction as each other, and cancel each other out,
It is a means for flowing the magnetic flux through the closed magnetic path core 25 to remove it.

With the above configuration, as shown in FIG. 13, when the common mode noise 26 propagates to the electric circuit, the directions of the magnetic fluxes A and B generated in the line filter are as shown in FIG.
It becomes as shown in.

That is, in FIG. 14, one winding 2
The magnetic flux A generated from the magnetic flux 3 and the magnetic flux B generated from the other winding 24 flow in the closed magnetic circuit core 25 so as to be in the same direction as each other, add to each other, and cancel each other.

[0008]

Generally, high frequency noise current generated in an electric circuit through a commercial power supply includes:
There are an in-phase current and a differential current. The former is called common mode noise, and the latter is called normal mode noise.

In the above conventional configuration, the common mode noise 2
6 can be removed, but at the same time, the normal mode noise cannot be removed.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a line filter capable of simultaneously removing both common mode noise and normal mode noise.

[0011]

In order to achieve the above object, the present invention provides a bobbin having a through hole, one winding and the other winding wound around the bobbin, and a bobbin having a through hole. And a first noise removing means for removing common mode noise and a second noise removing means for removing normal mode noise, wherein the first noise removing means comprises: Means for flowing the magnetic flux generated from the wire and the other winding in the same direction and canceling each other by flowing through the closed magnetic path magnetic core, and the second noise removing means comprises: The windings and the magnetic flux generated from the other winding are in opposite directions to each other, and are mutually non-cancelling,
In this configuration, it is configured to flow through the closed magnetic path core and remove the core.

With the above arrangement, the magnetic flux generated from the one winding and the other winding by the first noise removing means is
The common mode noise can be removed by flowing through the closed magnetic circuit core so as to be in the same direction as each other and cancel each other out, so that common mode noise can be removed. The magnetic flux generated from the wire
The current flows in the closed magnetic circuit core so that the directions are opposite to each other and cancel each other out, so that the normal mode noise can be removed, and both the common mode noise and the normal mode noise can be removed. .

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 is a bobbin having a through hole, one winding and the other winding wound around the bobbin, and a closed magnetic circuit inserted into the through hole of the bobbin. A first noise removing unit for removing common mode noise and a second noise removing unit for removing normal mode noise, wherein the first noise removing unit includes the one winding and the other. The magnetic flux generated from the windings, in the same direction as each other, so as to mutually cancel each other, as a means for flowing and removing the closed magnetic path core,
The second noise removing means removes the magnetic flux generated from the one winding and the other winding by flowing through the closed magnetic core so that the magnetic flux is generated in directions opposite to each other and mutually cancels out. This is the configuration.

With the above arrangement, the magnetic flux generated from the one winding and the other winding by the first noise removing means is
The common mode noise can be removed by flowing through the closed magnetic circuit core so as to be in the same direction as each other and cancel each other out, so that common mode noise can be removed. The magnetic flux generated from the wire
The current flows in the closed magnetic circuit core so that the directions are opposite to each other and cancel each other out, so that the normal mode noise can be removed, and both the common mode noise and the normal mode noise can be removed. .

According to a second aspect of the present invention, in the first aspect of the present invention, the bobbin is provided with a middle flange portion for dividing one winding and the other winding, and at least the middle flange portion of the bobbin is provided. The material is a magnetic material, and the second noise removing means causes the magnetic flux generated from the one winding and the other winding to flow in the closed magnetic circuit core so as to be in mutually opposite directions and to cancel each other out, and And means for removing the magnetic flux by flowing it through the middle flange of the bobbin so as to be in the same direction as each other.

According to the above configuration, since the material of at least the middle flange of the bobbin is made of a magnetic material, the magnetic flux generated in one winding and the other winding easily flows into the middle flange.

Thus, when the magnetic fluxes generated in the one winding and the other winding are made to flow in the closed magnetic core so as to be in mutually opposite directions and to cancel each other out, it is inevitable that
This magnetic flux flows in the middle flange portion of the bobbin so as to be in the same direction as each other, and each of the windings of one winding and the other winding mainly in the closed magnetic circuit core and the bobbin having low magnetic resistance. , A normal mode noise can be accurately removed.

According to a third aspect of the present invention, in the second aspect of the invention, the middle flange portion of the bobbin is brought close to the closed magnetic path magnetic core.

According to the above configuration, since the middle flange portion of the bobbin is brought close to the magnetic core of the closed magnetic circuit, the magnetic flux generated in one winding and the other winding easily flows to the middle flange portion,
A magnetic flux is generated around one winding and the other winding mainly in a closed magnetic circuit core and a bobbin having a low reluctance to more properly remove normal mode noise. Can be.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the bobbin-magnetic core includes an outer peripheral end surface of the middle flange portion of the bobbin and an inner peripheral surface of the closed magnetic circuit core located above the outer peripheral end surface. The distance is set so that the minimum distance of the bobbin-core distance is smaller than the gap size between the inner wall surface of the through hole of the bobbin and the outer peripheral surface of the closed magnetic path core located in the through hole. In addition, the maximum distance between the bobbin and the magnetic core is set to be larger than the gap size.

With the above construction, the minimum distance between the bobbin and the magnetic core between the outer peripheral end face of the middle flange portion of the bobbin and the inner side surface of the closed magnetic path magnetic core located above the outer peripheral end face is the minimum distance between the bobbin through-hole. Since the gap between the inner wall surface and the outer peripheral surface of the closed magnetic path magnetic core located in the through hole is made smaller, the distance between the bobbin and the magnetic core can be restricted, whereby
It is possible to prevent adverse effects caused by removing the normal mode noise and the common mode noise due to the distance between the bobbin and the magnetic core.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the outer peripheral end surface of the middle flange portion of the bobbin and the inner side surface of the closed magnetic circuit core are not in contact with each other.

With the above configuration, the middle flange portion of the bobbin does not contact the magnetic core of the closed magnetic circuit, and the adverse effects that occur when removing normal mode noise and common mode noise can be properly prevented.

Embodiment 1 Hereinafter, a line filter according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a magnetic circuit diagram showing the flow of magnetic flux caused by normal mode noise of a line filter according to an embodiment of the present invention, and FIG. 2 is an electric circuit showing propagation of normal mode noise when using the line filter. FIG. 3 is a magnetic circuit diagram showing the flow of magnetic flux caused by common mode noise of the line filter. FIG. 4 is an electric circuit diagram showing propagation of common mode noise when the line filter is used.
Is a perspective view of the line filter, and FIG. 6 is a front sectional view of the line filter.

5 and 6, a line filter according to an embodiment of the present invention includes a bobbin 2 having a through hole 1, one winding 3 and the other winding 4 wound around the bobbin 2. , And a square-shaped closed magnetic circuit core 5 inserted into the through hole 1 of the bobbin 2.

The bobbin 2 is provided with a middle flange portion 6 for dividing the one winding 3 and the other winding 4, and the bobbin 2 including the middle flange portion 6 is made of a ferrite resin made of a magnetic material. I have.

1 to 4, a first noise removing means for removing the common mode noise 11 and a second noise removing means for removing the normal mode noise 12 are provided. The magnetic flux A and the magnetic flux B respectively generated from the winding 3 and the other winding 4 are removed from the closed magnetic circuit core 5 by flowing in the closed magnetic circuit core 5 so as to be in the same direction as each other and to cancel each other out.

Further, the second noise removing means includes a magnetic flux A and a magnetic flux B generated from one winding 3 and the other winding 4.
Flow in the closed magnetic circuit core 5 so as to be opposite to each other and cancel each other, and flow the magnetic flux A and the magnetic flux B to the middle flange portion 6 of the bobbin 2 so as to be in the same direction. It is a means to remove.

Then, the middle flange 6 of the bobbin 2 is brought close to the closed magnetic path core 5, and the outer peripheral end face 7 of the middle flange 6 of the bobbin 2 and the closed magnetic path core 5 located above the outer peripheral end face 7 are formed. The distance H between the bobbin and the magnetic core with respect to the inner side surface 8 is the minimum distance between the inner wall surface 9 of the through hole 1 of the bobbin 2 and the outer peripheral surface 10 of the closed magnetic core 5 located in the through hole 1. T (T1 +
T2), and the maximum distance thereof is larger than the gap dimension T.
The outer peripheral end surface 7 of the middle flange portion 6 of the bobbin 2 is not in contact with the inner side surface 8 of the closed magnetic circuit core 5 located above the outer peripheral end surface 7.

The operation of the line filter having the above configuration will be described below. The first noise removing means causes the magnetic fluxes A and B generated from the one winding 3 and the other winding 4 to flow in the closed magnetic circuit core 5 in the same direction as each other and so as to cancel each other out. Since the common mode noise 11 can be removed, the magnetic flux A and the magnetic flux B generated from the one winding 3 and the other winding 4 can be reversed by the second noise removing means.
Since the current is removed by flowing through the closed magnetic circuit core 5 so as to cancel each other, the normal mode noise 12 can be removed, and both the common mode noise 11 and the normal mode noise 12 can be removed.

Further, since the material of at least the middle flange portion 6 of the bobbin 2 is a ferrite resin made of a magnetic material,
The magnetic flux A and the magnetic flux B generated in the one winding 3 and the other winding 4 easily flow through the middle flange portion 6, whereby the magnetic flux A generated in the one winding 3 and the other winding 4, Magnetic flux B
Flow in the closed magnetic circuit core 5 so as to be in the opposite directions and to cancel each other, the magnetic fluxes A,
The magnetic flux B flows through the middle flange 6 of the bobbin 2 so as to be in the same direction as each other, and the magnetic flux A and the magnetic flux B are generated around the respective windings of the one winding 3 and the other winding 4. In addition, the normal mode noise 12 can be accurately removed.

Further, since the middle flange portion 6 of the bobbin 2 is close to the closed magnetic path magnetic core 5, the magnetic fluxes A and B generated in the one winding 3 and the other winding 4 are very small. The magnetic flux A and the magnetic flux B are generated around each of the one winding 3 and the other winding 4 so that the normal mode noise 12 can be more accurately removed. .

The outer peripheral end face 7 of the middle flange 6 of the bobbin 2
The minimum distance between the bobbin 2 and the inner surface 8 of the closed magnetic path magnetic core 5 located above the outer peripheral end surface 7 is the minimum distance between the inner wall surface 9 of the through hole 1 of the bobbin 2 and the inside of the through hole 1. The clearance dimension T (T1 + T) between the outer peripheral surface 10 of the closed magnetic circuit core 5 located at
2) and the maximum distance is set to be larger than the gap size T.
The position H can be regulated between the bobbin and the magnetic core.

That is, when the closed magnetic circuit core 5 is simply inserted into the through hole 1 of the bobbin 2, the outer peripheral surface 1 of the closed magnetic circuit core 5
0 and the gap size T between the inner wall surface 9 of the through hole 1 and (T1 + T2)
The distance H between the bobbin and the magnetic core is very large, so that the magnetic flux A and the magnetic flux B hardly flow to the middle flange portion 6, which adversely affects the removal of the normal mode noise 12 and the middle flange of the bobbin 2. The portion 6 and the closed magnetic circuit core 5 come into contact with each other, which tends to cause magnetic saturation, degrade current superimposition characteristics, and adversely affect the removal of both the normal mode noise 12 and the common mode noise 11. Since the position of the distance H between the magnetic cores is regulated, the characteristics are not degraded, and it is possible to prevent adverse effects that occur when the normal mode noise 12 and the common mode noise 11 are removed.

Further, since the minimum distance H between the bobbin and the magnetic core is larger than 0, the middle flange portion 6 of the bobbin 2 does not come into contact with the closed magnetic core 5 and the normal mode noise 12 In addition, it is possible to appropriately prevent the adverse effect generated when the common mode noise 11 is removed.

As described above, according to the embodiment of the present invention, the magnetic flux A and the magnetic flux B generated from the one winding 3 and the other winding 4 are made to have the same direction by the first noise removing means. At the same time, the common mode noise 11 can be removed by flowing to the closed magnetic circuit core 5 so as to cancel each other out, so that the one winding 3 and the other winding 4 can be removed by the second noise removing means. The normal mode noise 12 can be removed because the magnetic flux A and the magnetic flux B that are generated are caused to flow in the closed magnetic circuit core 5 so as to be opposite to each other and to cancel each other, so that the normal mode noise 12 can be removed. Both normal mode noise 11 and normal mode noise 12 can be removed.

Further, since at least the material of the middle flange portion 6 of the bobbin 2 is made of a magnetic material, the normal mode noise 1
2 can be accurately removed, and since the middle flange portion 6 of the bobbin 2 is close to the closed magnetic circuit core 5, the normal mode noise 12 can be more accurately removed.

Further, the outer peripheral end face 7 of the middle flange 6 of the bobbin 2
The minimum distance between the bobbin 2 and the inner surface 8 of the closed magnetic path magnetic core 5 located above the outer peripheral end surface 7 is the minimum distance between the inner wall surface 9 of the through hole 1 of the bobbin 2 and the inside of the through hole 1. The clearance dimension T (T1 + T) between the outer peripheral surface 10 of the closed magnetic circuit core 5 located at
2) and the maximum distance is set to be larger than the gap size T.
The position H of the bobbin-magnetic core distance can be regulated, and the adverse effects that occur when the normal mode noise 12 and the common mode noise 11 are removed can be prevented. In particular, since the minimum distance H between the bobbin and the magnetic core is larger than 0, the bobbin 2
The normal mode noise 12 and the common mode noise 11
It is possible to properly prevent the adverse effect that occurs when removing the slag.

In the line filter according to the embodiment of the present invention, although a square-shaped closed magnetic circuit core 5 is used,
Similar effects can be obtained by using a closed magnetic circuit core 13 having a sun-shape as shown in FIGS.

In this case, the flows of the magnetic fluxes A and B caused by the common mode noise 11 are as shown in FIG. 9, and the flows of the magnetic fluxes A and B caused by the normal mode noise 12 are as shown in FIG. Become.

[0042]

As described above, according to the present invention, the first noise removing means causes the magnetic fluxes generated from the one winding and the other winding to be in the same direction as each other and to cancel each other. Since the common mode noise can be removed by flowing the magnetic flux through the closed magnetic circuit core, the magnetic flux generated from the one winding and the other winding can be removed by the second noise removing means in the opposite directions. To provide a line filter capable of removing normal mode noise and removing both common mode noise and normal mode noise because the current is removed by flowing through a closed magnetic circuit core so as to cancel each other out. Can be.

[Brief description of the drawings]

FIG. 1 is a magnetic circuit diagram showing a magnetic flux flow caused by normal mode noise of a line filter according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing propagation of normal mode noise when the line filter is used.

FIG. 3 is a magnetic circuit diagram showing a flow of a magnetic flux caused by common mode noise of the line filter.

FIG. 4 is an electric circuit diagram showing propagation of common mode noise when the line filter is used.

FIG. 5 is a perspective view of the line filter.

FIG. 6 is a front sectional view of the line filter.

FIG. 7 is a perspective view of a line filter using a sun-shaped closed magnetic circuit core;

FIG. 8 is a cross-sectional plan view of the line filter.

FIG. 9 is a magnetic circuit diagram showing a flow of a magnetic flux caused by common mode noise of the line filter.

FIG. 10 is a magnetic circuit diagram showing a magnetic flux flow caused by normal mode noise of the line filter.

FIG. 11 is a perspective view of a conventional line filter.

FIG. 12 is a front sectional view of the line filter.

FIG. 13 is an electric circuit diagram showing propagation of common mode noise when the line filter is used.

FIG. 14 is a magnetic circuit diagram showing a flow of a magnetic flux caused by common mode noise of the line filter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 through hole 2 bobbin 3 one winding 4 the other winding 5 closed magnetic path magnetic core 6 middle flange 7 outer peripheral end surface 8 inner side surface 9 inner wall surface 10 outer peripheral surface 11 common mode noise 12 normal mode noise 13 sun-shaped closed magnetic field Road core

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Tomita 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5E070 AA01 AB01 AB03 BA03 BA14 CA03 CA12 CA14 CA15 EA08 EB03

Claims (5)

[Claims] 1. A bobbin having a through hole, one winding and the other winding wound around the bobbin, and a closed magnetic circuit core inserted into the through hole of the bobbin, for removing common mode noise. And a second noise removing unit for removing normal mode noise, wherein the first noise removing unit causes the magnetic flux generated from the one winding and the other winding to be equal to each other. Direction, and cancel each other so as to cancel each other, so as to remove the magnetic flux flowing through the closed magnetic core, the second noise removing means, the magnetic flux generated from the one winding and the other winding, As they go in the opposite direction and offset each other,
A line filter as a means for flowing and removing the magnetic flux through the closed magnetic circuit core. 2. A bobbin provided with a middle flange portion for dividing one of the windings and the other winding, and a material of at least the middle flange portion of the bobbin is made of a magnetic material. The magnetic flux generated from the winding and the other winding flows in the closed magnetic path core so that the directions are opposite to each other and cancel each other, and the bobbin of the bobbin is set so that the magnetic flux is in the same direction as each other. 2. The line filter according to claim 1, wherein said line filter is a means for flowing down and removing said middle collar. 3. The line filter according to claim 2, wherein the middle flange portion of the bobbin is close to the closed magnetic circuit core. 4. The minimum distance between the bobbin and the magnetic core between the outer peripheral end surface of the middle flange portion of the bobbin and the inner surface of the closed magnetic circuit core located above the outer peripheral end surface is the minimum distance between the bobbin and the magnetic core. 3. The line filter according to claim 2, wherein a gap between an inner wall surface of the through hole of the bobbin and an outer peripheral surface of the closed magnetic core located in the through hole is smaller than a gap size. 5. The line filter according to claim 4, wherein the outer peripheral end surface of the middle flange portion of the bobbin and the inner side surface of the closed magnetic circuit core are not in contact with each other.