JP2000068134A - Choke coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the two kinds of choke coils by one each of a coil, a winding wire and a magnetic core relating to the choke coil for noise prevention used in electronic equipment or the like for public welfare or industries. SOLUTION: A closed magnetic path magnetic core 3 is attained by abutting an inner cylinder and an outer cylinder on the respective unclosed end sides of the two magnetic cores 4 and 5 in the shape of being closed on one end side of them, one coil 1 is housed in a space between the inner cylinder and the outer cylinder of the closed magnetic path magnetic core 3, and the winding wire 2 is wound on the outer peripheral surface of the closed magnetic path magnetic core 3 so as to generate a magnetic flux orthogonal to the magnetic flux generated by the coil 1. Since the two kinds of these choke coils are constituted even of one each of the coil 1, the winding wire 2 and the closed magnetic path magnetic core 3, the number of components is reduced and the light-weight, small-sized and inexpensive choke coil is obtained.

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 preventing noise used in consumer or industrial electronic equipment.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. First, according to the figure, a coil housing portion is provided by having an inner cylinder and an outer cylinder using Mn-Zn ferrite, closing them at one end side, and combining the other end side with a magnetic gap spacer 22 therebetween. First hollow magnetic core 2
A first mode coil 23 and a second mode coil 24 are wound into a normal mode choke coil in the 0 and second hollow magnetic core 21, and the core 2 is passed through the bores of the magnetic cores 20 and 21.
The first winding 25 and the second winding 26 are wound around the outer peripheral surfaces 0 and 21 such that the directions of the generated magnetic fluxes cancel each other in the normal mode and add each other in the common mode. is there.

A choke coil configured as described above is inserted into a power-supplying portion of an electronic device to prevent a switching noise or the like generated from a switching power supply, and a common-mode choke coil for suppressing harmonics. It has a large inductance (1 mH to 10 mH), and has both functions of a normal mode choke coil having a large magnetic core cross-sectional area with a gap so as not to be saturated by a fundamental wave having a large amplitude or a harmonic current. -13120).

Here, an inductance L1 formed on a line by two normal mode choke coils is used.
Is represented by (Equation 1), where S is the cross-sectional area of the magnetic core of each coil, μ is the magnetic permeability, l is the magnetic path length, and N1 is the number of turns of the coil.

[0005]

(Equation 1)

[0006]

The above-mentioned choke coil has a large inductance (1 mH to 10 mH) for suppressing harmonics and has a gap so as not to be saturated by a fundamental wave having a large amplitude or a harmonic current. Since two coils each having a large magnetic core cross-sectional area are inserted into each of the two power supply lines, at least two coils for the normal mode are required. However, the same effect can be obtained even if the power supply line is inserted into one of the power supply lines in order to suppress the harmonics. In addition, when a normal mode choke coil for EMI noise suppression is configured, the above-described condition is provided if a common mode choke coil exists. The performance can be satisfied by inserting a choke coil with smaller inductance into one of the power supply lines than in the case of, and having two coils is an obstacle to miniaturization, and the number of parts increases the complexity of the process and the cost. It was a factor of up.

The present invention aims at a choke coil having a small size and excellent characteristics.

[0008]

In order to solve the above-mentioned problems, a choke coil according to the present invention has one coil wound inside a closed magnetic circuit core in a circumferential direction of the closed magnetic circuit core, and a winding formed on the closed magnetic circuit core. This choke coil is wound around the outer peripheral surface of a closed magnetic circuit core through a middle hole, and a magnetic flux generated by the coil and a magnetic flux generated by the winding are orthogonal to each other.

With the above configuration, even a single normal mode coil can be formed, so that the number of components can be reduced, and a light-weight, small, and inexpensive choke coil can be obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a closed magnetic circuit in which an inner cylinder and an outer cylinder and two magnetic cores of which shapes are closed at one end thereof are respectively butted at unclosed ends. One coil is housed in the space between the inner cylinder and the outer cylinder of the closed magnetic path core, and a magnetic flux orthogonal to the magnetic flux generated by the coil is formed on the outer peripheral surface of the closed magnetic path core. With the configuration in which the windings are wound, two choke coils can be configured with one element even if only one coil, one winding, and one magnetic core are provided, and cost reduction and man-hour reduction are achieved by reducing the number of components. be able to. In addition, the downsizing can reduce the mounting area, the material, and the loss. Furthermore, when the same inductance as that obtained by two coils is obtained by one coil, the number of turns of the coil can be reduced, and the size and the rise in temperature can be reduced. On the other hand, when one coil has the same size as two coils, that is, when one coil is formed by the number of turns of two coils, twice the inductance of two coils can be secured, and further noise can be obtained. Reduction can be realized.

The invention according to claim 2 of the present invention has a structure in which one coil is incorporated in a closed magnetic circuit core with a gap spacer having a groove through which the coil passes at the abutting portion of the magnetic core interposed therebetween. In addition to the same effect, a gap can be provided for the magnetic flux generated by the coil to prevent magnetic saturation when a large current flows.

According to a third aspect of the present invention, by providing one of the inner cylinder and the outer cylinder of the magnetic core to be higher than the other, the same effect as in the second aspect is obtained, and the gap spacer and the like are provided. A gap can be provided for the magnetic flux generated by the coil without using the above components, and the number of parts, man-hours, and cost can be reduced as compared with the second aspect.

According to a fourth aspect of the present invention, a normal mode choke coil is formed by a coil built in a closed magnetic circuit core, and a normal mode choke coil is formed by a winding wound around the outer peripheral surface of the closed magnetic circuit core. With this configuration, in addition to the same effects as those of the first aspect, two normal mode choke coils can be configured with one element, and the noise generated on each line by connecting to both lines of the circuit is greatly reduced. it can. In addition, when mounted on a circuit, a capacitor, a resistor, a varistor, and the like are added between the coils to form a filter circuit, thereby further reducing noise. Furthermore, cost reduction and man-hour reduction can be achieved by reducing the number of parts. The downsizing can reduce the mounting area, reduce materials, and reduce loss. It is also possible to arrange the normal mode choke coils in two lines on one side line by changing the wiring order with the same element.

According to a fifth aspect of the present invention, a normal mode choke coil is formed by a coil built in a closed magnetic circuit core, and magnetic fluxes generated in the normal mode on the outer peripheral surface of the closed magnetic circuit core cancel each other out. In the common mode, the two windings are wound in the direction in which the magnetic fluxes generated are added to form a common mode choke coil.
In addition to the same effects as those of the first aspect, an element exhibiting the characteristics of the normal mode choke coil and the common mode choke coil can be constituted by one element. Therefore, low-frequency noise can be reduced in the normal mode choke coil portion, and high-frequency noise can be reduced in the common mode choke coil portion, so that it is possible to reduce noise over a wide band with one element. Further, at the time of mounting on a circuit, a capacitor, a resistor, a varistor, and the like can be added between the coils to form a filter circuit to further reduce noise. Furthermore, cost reduction and man-hour reduction can be achieved by reducing the number of parts. And the downsizing of the mounting area by downsizing,
Material can be reduced and loss can be reduced. It is also possible to arrange the normal mode choke coil in the subsequent stage and the common mode choke coil in the preceding stage by changing the wiring order with similar elements.

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the finished product, FIG. 2 is a sectional view, and FIG. 3 is an exploded perspective view. According to the figure, 1 is a coil, 2 is a winding, 3 is a closed magnetic circuit core formed by abutting portions of two cores 4 and 5 which close the inner cylinder and the outer cylinder at one end thereof and which are not closed. A magnetic flux generated by the coil 1 and a magnetic flux 7 generated by the winding 2.

The configuration and operation will be described below. The magnetic cores 4 and 5 are abutted on the unblocked side, the coil 1 is housed in the space between the inner cylinder and the outer cylinder, and a magnetic flux 6 is generated around the coil 1 built in the closed magnetic core 3. Then, the winding 2 is wound around the outer peripheral surface of the closed magnetic circuit core 3 through the middle hole of the closed magnetic circuit core 3, and the magnetic flux 7 is generated in the outer peripheral direction of the closed magnetic circuit core 3. That is, two magnetic fluxes are generated in one closed magnetic path magnetic core 3 in directions orthogonal to each other.

Therefore, according to the above configuration, two types of choke coils can be constituted by one coil 1, the winding 2 and the closed magnetic circuit core 3, respectively, and the number of parts can be reduced to reduce cost and man-hours. . Further, the miniaturization can reduce the weight, the mounting area, the material used, and the loss such as copper loss. Furthermore, two magnetic cores 4,5
Can be formed in the same shape, and when the magnetic cores 4 and 5 are molded by a metal mold, the magnetic cores 4 and 5 can be manufactured with one type of metal mold. Further, the inductance L2 formed on the line by one choke coil is represented by the following equation, where S is the sectional area of the magnetic core of each coil, μ is the magnetic permeability, l is the magnetic path length, and N2 is the number of turns of the coil. ).

[0018]

(Equation 2)

Therefore, for example, when obtaining the same inductance as the conventional one, the number of windings may be multiplied by √2 compared with (Equation 1), and if N2 = √2N1, then

[0020]

(Equation 3)

## EQU1 ## Therefore, the total number of turns of the coil is smaller than that of two conventional normal mode chokes, so that a small-sized, light-weight, inexpensive choke coil can be formed, and the temperature rise can be reduced due to the short copper wire length.

Conversely, if one coil has the same size as two coils, that is, if one coil has the number of turns of two coils, N2 = 2 · N1 in (Equation 2) substitute.

[0023]

(Equation 4)

Therefore, an inductance twice that of the case of two coils can be secured, and further noise reduction can be realized.

(Embodiment 2) A second embodiment of the present invention will be described with reference to FIGS. 4 is a perspective view of the finished product, FIG. 5 is a sectional view, and FIG. 6 is an exploded perspective view. According to the figure, 1 is a coil, 2 is a winding, 3 is a closed magnetic circuit core formed by abutting portions which do not block magnetic cores 4 and 5 which close the inner and outer cylinders at one end thereof, and 6 is a coil. 1, a magnetic flux generated by the winding 2; and 8, a gap spacer.

The configuration and operation will be described below. The coil 1 wound in advance is housed so as to be sandwiched between the inner cylinder and the outer cylinder of the two magnetic cores 4 and 5 with the gap spacer 8 interposed therebetween, and the winding 2 is formed of the two magnetic cores 4 and 5 and the gap spacer 8. It is wound around the outer peripheral surface of the closed magnetic circuit core 3 through the middle hole.

Therefore, in addition to the same effects as in the first embodiment,
By sandwiching the gap spacer 8 between the two magnetic cores 4 and 5, a gap can be provided in the magnetic path through which the magnetic flux 6 passes, and the magnetic saturation of the closed magnetic path core 3 can be prevented even when a large current flows. Since the magnetic flux 6 can be
Can be reduced in size, the size can be reduced, the mounting area can be reduced, materials used can be reduced, and losses such as copper loss can be reduced. Further, by changing the thickness of the gap spacer 8, the dimension of the gap can be easily and surely adjusted, and the inductance and the DC superimposition characteristic can be arbitrarily adjusted.

(Embodiment 3) A third embodiment of the present invention will be described with reference to FIGS. 7 is a perspective view of the finished product, FIG. 8 is a sectional view, and FIG. 9 is an exploded perspective view. According to the drawing, 1 is a coil, 2 is a winding, 3 is a closed magnetic circuit core formed by abutting portions that do not block magnetic cores 4 and 5 which close the inner and outer cylinders at one end thereof, and 6 is the coil 1
And 7 is a magnetic flux generated by the winding 2.

The configuration and operation will be described below. The magnetic cores 4 and 5 are butted on the side not closed, the coil 1 is housed in the space between the inner cylinder and the outer cylinder, and a magnetic flux 6 is generated in the circumferential direction of the coil 1 in the closed magnetic circuit core. Then, the winding 2 is wound around the outer peripheral surface of the closed magnetic circuit core 3 through the middle hole of the closed magnetic circuit core 3,
, A magnetic flux 7 is generated in the circumferential direction. That is, two magnetic fluxes are generated in one magnetic core in directions orthogonal to each other.

Accordingly, the inner cylinders of the butted magnetic cores 4, 5
Since a gap is formed at one of the shorter butted portions of the outer cylinder, in addition to the same effect as in the second embodiment, a gap can be provided for the magnetic flux generated by the coil 1 without using a component such as a gap spacer. The number of parts, man-hours, and cost can be reduced as compared with the second embodiment. Further, since heat can be radiated from the gap, a rise in temperature can be reduced.

(Embodiment 4) A fourth embodiment of the present invention will be described with reference to FIGS. 10 is a perspective view of the finished product, FIG. 11 is a sectional view, FIG. 12 is an exploded perspective view, FIG. 13 is a connection diagram, and FIG. 14 is a circuit configuration diagram. According to the drawing, reference numeral 1 denotes a coil wound inside the closed magnetic path core 3 in the circumferential direction of the closed magnetic path core 3, and 2 denotes a coil wound around the outer peripheral surface of the closed magnetic path core 3 through the middle hole of the closed magnetic path core 3. 3 is a closed magnetic circuit core having a gap 9, 6 is a magnetic flux generated by the coil 1, 7 is a magnetic flux generated by the winding 2, 8 is a gap spacer, 10 is a power supply, 11 is a load, and 12 is a line current. It is.

The structure and operation will be described below. The coil 1 is wound in advance, and the two magnetic cores 4, 5
The winding 2 is wound around the outer peripheral surface of the closed magnetic path core 3 through the closed magnetic path core 3 and the middle hole of the gap spacer 8. Then, one end of the coil 1 is connected to the power supply 10, and the other end of the coil 1 is connected to the load 11. And load 1
The other end of the winding 1 is connected to one end of the winding 2, and the other end of the winding 2 is connected to the other end of the power supply 10. At this time, coil 1
Generates a magnetic flux 6 and a gap 9 in a magnetic path through which the magnetic flux 6 passes.
Are provided to form a normal mode choke coil, and a gap 9 is provided in a magnetic path through which a magnetic flux 7 that also generates the winding 2 passes to form a normal mode choke coil.

Therefore, with the above configuration, two normal mode choke coils can be constituted by one element, and the noise generated in each line connected to both lines of the circuit can be greatly reduced. In addition, when mounted on a circuit, a capacitor, a resistor, a varistor, and the like are added between the coils to form a filter circuit, thereby further reducing noise.
Furthermore, cost reduction and man-hour reduction can be achieved by reducing the number of parts. The downsizing can reduce the mounting area, reduce materials, and reduce loss. It is also possible to arrange the normal mode choke coils in two lines on one side line by changing the wiring order with the same element.

(Embodiment 5) A fifth embodiment of the present invention will be described with reference to FIGS. 15 is a perspective view of the completed product, FIG. 16 is a cross-sectional view, FIG. 17 is an exploded perspective view, FIGS. 18 and 19 are connection diagrams showing the directions of magnetic flux depending on the direction of each current flow, and FIG. 20 is a circuit configuration diagram. It is.
According to the figure, 1 is a coil wound around the closed magnetic path core 3 in the circumferential direction of the closed magnetic path core 3, and 13 and 14 are closed magnetic path cores 3.
The first wound around the outer peripheral surface of the closed magnetic core 3
, A second winding, 3 a closed magnetic core, 6 a magnetic flux generated by the coil 1, 7 a magnetic flux generated by the windings 13 and 14, 8 a gap spacer, 10 a power supply, 11 a load, 12 is a line current, and 15 is a current flowing in the same direction.

The configuration and operation will be described below. The coil 1 is wound in advance, and the two magnetic cores 4, 5
The windings 13 and 14 are closed, and the windings 13 and 14 are closed.
It is wound around the outer peripheral surface of the closed magnetic circuit core 3 through the middle hole of the gap spacer 8. Then, one end of the coil 1 is connected to the power supply 10, the other end of the coil 1 is connected to one end of the winding 13,
The other end of the winding 13 is connected to the load 11. Then, the other end of the load 11 is connected to one end of the winding 14, and the other end of the winding 14 is connected to the other end of the power supply 10. At this time, the coil 1 generates a magnetic flux 6 in the circumferential direction of the coil 1 in the closed magnetic circuit core 3, and a gap spacer 8 is provided in a magnetic path through which the magnetic flux 6 passes to form a normal mode choke coil. Then, the windings 13 and 14 generate a magnetic flux 7 with respect to the line current 12.
Are cancelled, and are wound in a direction in which the magnetic flux 7 is added to the current 15 in the same direction, thereby forming a common mode choke coil.

Accordingly, with the above configuration, an element exhibiting the characteristics of the normal mode choke coil and the common mode choke coil can be constituted by one element as shown in FIG. Therefore, low-frequency noise can be reduced in the normal mode choke coil portion, and high-frequency noise can be reduced in the common mode choke coil portion, so that it is possible to reduce noise over a wide band with one element. Further, at the time of mounting on a circuit, a capacitor, a resistor, a varistor, and the like can be added between the coils to form a filter circuit to further reduce noise. Furthermore, cost reduction and man-hour reduction can be achieved by reducing the number of parts. The downsizing can reduce the mounting area, reduce materials, and reduce loss. It is also possible to arrange the normal mode choke coil in the subsequent stage and the common mode choke coil in the preceding stage by changing the wiring order with similar elements.

[0037]

As described above, the choke coil according to the present invention is a closed magnetic circuit core in which the inner cylinder and the outer cylinder and the two cores which are closed at one end thereof are respectively butted at the unblocked ends. One coil is housed in the space between the inner cylinder and the outer cylinder of the closed magnetic circuit core, and a winding is formed on the outer peripheral surface of the closed magnetic circuit core so as to generate a magnetic flux orthogonal to the magnetic flux generated by the coil. Due to the winding configuration, two types of choke coils can be formed even with one coil, one winding, and one magnetic core, so that the number of parts can be reduced, and it is lightweight for EMI noise suppression and harmonic current suppression. A small and inexpensive choke coil can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a choke coil according to an embodiment of the present invention.

FIG. 2 is a sectional view of the embodiment.

FIG. 3 is an exploded perspective view of the embodiment.

FIG. 4 is a perspective view of another embodiment.

FIG. 5 is a cross-sectional view of another embodiment.

FIG. 6 is an exploded perspective view of another embodiment.

FIG. 7 is a perspective view of another embodiment.

FIG. 8 is a cross-sectional view of another embodiment.

FIG. 9 is an exploded perspective view of another embodiment.

FIG. 10 is a perspective view of another embodiment.

FIG. 11 is a sectional view of another embodiment.

FIG. 12 is an exploded perspective view of another embodiment.

FIG. 13 is a connection diagram of another embodiment.

FIG. 14 is a circuit configuration diagram of another embodiment.

FIG. 15 is a perspective view of another embodiment.

FIG. 16 is a sectional view of another embodiment.

FIG. 17 is an exploded perspective view of another embodiment.

FIG. 18 is a connection diagram of another embodiment.

FIG. 19 is a connection diagram of another embodiment.

FIG. 20 is a circuit configuration diagram of another embodiment.

FIG. 21 is a perspective view of a conventional choke coil.

FIG. 22 is an exploded perspective view of a conventional choke coil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coil 2 winding 3 Closed magnetic core 4,5 Magnetic core 6 Magnetic flux generated by coil 7 Magnetic flux generated by winding 8 Gap spacer 9 Gap 10 Power supply 11 Load 12 Line current 13,14 Winding 15 Current flowing in the same direction

Claims (5)

[Claims] An inner cylinder, an outer cylinder, and two non-blocking ends of two cores closed at one end of the inner cylinder and the outer cylinder form a closed magnetic circuit core. A choke coil in which one coil is housed in a space between the coils, and a winding is wound around an outer peripheral surface of the closed magnetic circuit core so as to generate a magnetic flux orthogonal to the magnetic flux generated by the coil. 2. The choke coil according to claim 1, wherein a coil is built in the closed magnetic path core with a gap spacer having a groove through which the coil passes at the butting portion of the core. 3. The choke coil according to claim 1, wherein one of the inner cylinder and the outer cylinder of the magnetic core is higher than the other. 4. The choke coil according to claim 1, wherein a normal mode choke coil is formed by a coil built in the closed magnetic circuit core, and a normal mode choke coil is formed by a winding wound around the outer peripheral surface of the closed magnetic circuit core. . 5. A normal mode choke coil comprising a coil incorporated in a closed magnetic circuit core, wherein magnetic fluxes generated in a normal mode on the outer peripheral surface of the closed magnetic circuit core cancel each other,
2. The choke coil according to claim 1, wherein the common mode choke coil is formed by winding two windings in a direction in which magnetic fluxes generated in the common mode are added.