JP2014212163A - Choke coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact choke coil that implements saved resources of a magnetic core and an improved inductance mainly owing to a devised shape of the magnetic core.SOLUTION: The choke coil includes: a magnetic core 1 formed integrally, having a center core part 11 and side core parts 121, 122 and having connection parts 13 connecting the center core part 11 and opposite longitudinal end portions of the side core parts 121, 122 to constitute a closed magnetic circuit; a divisible gear bobbin having a gear part; a winding; and a terminal block. The gear bobbin is arranged on the center core part 11. The winding is wound on the gear bobbin. The magnetic core 1 and the gear bobbin are arranged on the terminal block. Outer peripheral surfaces at boundaries between the side core parts 121, 122 and the connection parts 13 constitute curved surfaces along directions of a magnetic flux generated by energization of the winding.

Description

  The present invention relates to a choke coil in which a magnetic core is wound and an inductance generated by energizing the winding is used.

  A bobbin having ridges at both ends, a winding wound around the outer periphery of the bobbin, and a middle leg portion inserted into the through-hole of the bobbin, and an opposing leg portion facing the middle leg portion is disposed outside the bobbin. Patent Document 1 discloses a configuration of a line filter including a sun-shaped closed magnetic path magnetic core and a terminal plate that arranges and holds the closed magnetic path magnetic core in the horizontal direction.

  Further, Patent Document 2 discloses a configuration of a small transformer in which two iron cores each having a center leg and left and right legs and having a center leg extending in the left and right leg direction are combined and inserted from both sides of a bobbin. Yes.

JP 2000-195730 A JP 61-39511 A

  The line filter, which is a kind of choke coil described in Patent Document 1, has a problem that sufficient noise removal performance cannot be obtained because the inductance is limited by the shape of the magnetic core. Further, even if the iron core of the small transformer described in Patent Document 2 is incorporated in the line filter of Patent Document 1, since the iron core is divided, the divided portion of the iron core becomes a magnetic gap, and high inductance cannot be obtained. There is a problem.

  Accordingly, an object of the present invention is to provide a small choke coil that can conserve resources and improve inductance mainly by devising the shape of the magnetic core.

  In order to solve the above problems, the present invention provides a closed magnetic circuit that is integrally formed and has a central core portion and left and right side core portions, and further includes a connection portion that connects the central core portion and the end of the side core portion. A magnetic core, a separable gear bobbin having a gear part, a winding, and a terminal block having a terminal, wherein the gear bobbin is disposed in the core part, and the winding is wound around the gear bobbin; The magnetic core and the gear bobbin are arranged on the terminal block, and the outer peripheral surface at the boundary between the side core portion and the connecting portion has a curved surface along the direction of the magnetic flux generated by energizing the winding. The problem is solved by the constituent choke coil.

  The corners of the outer periphery at the boundary between the side core portion and the connecting portion of the magnetic core have a low magnetic flux density and do not substantially contribute to the inductance. Therefore, resource saving of the magnetic core can be achieved by reducing the outer corners.

  Moreover, it is preferable that the inner peripheral surface at the boundary between the core portion and the connection portion constitutes a curved surface along the direction of the magnetic flux.

  The corner portion of the inner periphery at the boundary between the side core portion and the connection portion of the magnetic core has a high magnetic flux density. By making it a curved surface, the magnetic path length can be shortened, the magnetic resistance can be lowered, and the inductance can be improved.

  The inner peripheral surface is a curved surface with a radius Rin, the outer peripheral surface is a curved surface with a radius Rout, and Rin ≧ 0..., Where Th is the thickness of the side core portion in the direction facing the central core portion. It is desirable that the relationship is 2Th, 0 <Rout ≦ Th + Rin.

  By satisfying such a relational expression, it is possible to achieve both resource saving of the magnetic core and improvement of the inductance.

  In addition, it is preferable that the cross section of the core portion perpendicular to the direction of the magnetic flux is configured as a region surrounded by a closed curve including an arc centered on the central axis of the core portion.

  With such a configuration, the occupation ratio of the center portion of the inner peripheral region of the gear bobbin is improved, so that the gear bobbin can be downsized and the resource saving of the gear bobbin and the winding can be achieved.

  The magnetic core is ferrite, and the extending direction of the terminal is perpendicular to a plane including the center core portion, the side core portion, and the connection portion, and has two side core portions, the side core The magnetic cores form a sun-shaped shape by arranging the parts on both sides of the core part, and the sum of the cross-sectional areas perpendicular to the longitudinal direction of the two side core parts is It is desirable that it is 160% or more and 220% or less of the sectional area perpendicular to the longitudinal direction of the part.

  With such a cross-sectional area ratio, the inductance can be further improved.

  Further, it is desirable to have a common mode choke coil that has two winding sets with the same number of turns and absorbs or blocks common mode noise by the winding set.

  This is because the magnetic core obtained by the present invention has a high inductance and can be suitably used as a so-called common mode choke coil.

  According to the present invention, it is possible to provide a small choke coil that can conserve resources and improve inductance mainly by devising the shape of the magnetic core.

It is a perspective view which shows the magnetic core of Embodiment 1 in the choke coil of this invention. It is a top view which shows the magnetic core of Embodiment 1 in the choke coil of this invention. It is sectional drawing which shows the magnetic core of Embodiment 1 in the choke coil of this invention, and has shown sectional drawing of the AA surface in FIG. 1, FIG. It is a perspective view which shows Embodiment 1 of the choke coil of this invention. It is a perspective view which shows the magnetic core of Embodiment 2 in the choke coil of this invention. It is a perspective view which shows Embodiment 2 of the choke coil of this invention. It is a figure which shows the _AL value and volume of the magnetic core in the Example of this invention, and a comparative example. It is a figure which shows the coupling coefficient of the magnetic core in the Example of this invention, and a comparative example. It is a figure which shows magnetic flux distribution of the magnetic core in this invention. FIG. 9A shows the magnetic flux distribution when the radii Rin and Rout are both 0, and FIG. 9B shows the magnetic flux distribution when the radius Rin is 1.50 mm and the radius Rout is 4.00 mm. . It is a figure which shows the relationship between the ratio of the total cross-sectional area of the side core part with respect to the core area cross-sectional area of the magnetic core in this invention, and the inductance value at the time of winding on a core part.

(Embodiment 1)
FIG. 1 is a perspective view showing the magnetic core of Embodiment 1 in the choke coil of the present invention.

  The magnetic core 1 has a core 11, side cores 121, 122 on both sides thereof, and a connecting part 13 that connects the longitudinal ends of the core 11 and the side cores 121, 122. It has a letter shape.

  FIG. 2 is a plan view showing the magnetic core of Embodiment 1 in the choke coil of the present invention.

  Here, the boundary part between the side core parts 121 and 122 and the connection part 13 is configured by a curved surface having an inner peripheral surface with a radius Rin and an outer peripheral surface with a radius Rout.

  The middle core portion 11 has a width W and is separated from the side core portions 121 and 122 by a distance Lc.

  The side core parts 121 and 122 and the connection part 13 have a thickness Th.

  The middle core part 11 and the side core parts 121 and 122 have a length Lm.

  FIG. 3 is a cross-sectional view showing the magnetic core of Embodiment 1 in the choke coil of the present invention, and shows cross-sectional views of the AA plane in FIGS. 1 and 2.

  The center core portion 11 is configured by a curved surface formed by an arc from the central axis of the center core portion 11 at a portion facing the side core portions 121 and 122 being a flat surface and the other portions.

  By constructing a curved surface made of the above-mentioned arc on at least a part of the core portion 11, the volume occupancy of the core portion 11 with respect to the inner region of the gear bobbin, which will be described later, can be improved. Since the cross-sectional area of the core part 11 can be maintained equal, the gear bobbin can be reduced in size, and the amount of winding and copper used as the winding material can be reduced.

  Here, the arc of the core portion 11 has a diameter φ from the central axis.

  The side core parts 121 and 122 have a height To.

  The connecting portion 13 has a slope having a height Ts from the boundary portion with the middle core portion 11 toward the boundary portions of the side core portions 121 and 122.

  FIG. 4 is a perspective view showing Embodiment 1 of the choke coil of the present invention.

  The choke coil of this embodiment is prepared by attaching the gear bobbin 2 to the magnetic core 1, attaching the winding 21 around the terminal block 3, and connecting both ends of the winding 21 to the terminal 31. it can.

  In addition, when using a high magnetic permeability soft magnetic material such as MnZn ferrite as the magnetic core, the effect of the high inductance characteristics of the present invention can be enjoyed more suitably.

  For example, by forming a common mode choke coil with a pair of two windings having the same number of turns as the winding 21, the high inductance characteristic of the magnetic core can be utilized.

  Similarly, it is possible to configure a transformer by configuring the winding 21 from a plurality of windings.

(Embodiment 2)
FIG. 5 is a perspective view showing a magnetic core according to a second embodiment of the choke coil of the present invention.

  The difference from Embodiment 1 is that it is a single side core 12. The boundary portion between the side core portion 12 and the connection portion 13 has an inner peripheral surface and an outer peripheral surface formed of a curved surface.

  FIG. 6 is a perspective view showing Embodiment 2 of the choke coil of the present invention.

  The choke coil of this embodiment is prepared by attaching the gear bobbin 2 to the magnetic core 1, attaching the winding 21 around the terminal block 3, and connecting both ends of the winding 21 to the terminal 31. it can.

  The whole example was configured as in the first embodiment shown in FIG.

  The sun-shaped magnetic core is MnZn ferrite, and the dimensions shown in FIGS. 2 and 3 are such that the width W is 4.60 mm, the distance Lc is 5.45 mm, the thickness Th is 2.50 mm, and the length Lm. Was 15.90 mm, the diameter φ was 5.20 mm, the height To was 7.50 mm, and the height Ts was 2.00 mm.

  Further, regarding the radii Rin and Rout which are the dimensions of the magnetic core, Example 1 has Rin of 0.50 mm, Rout of 3.00 mm, Example 2 has Rin of 1.00 mm, Rout of 3.50 mm, and Example 3 Rin was 1.50 mm and Rout was 4.00 mm.

  In the comparative example, the radii Rin and Rout, which are the dimensions of the magnetic core, are zero. That is, the boundary part of the center core part 11 and the side core parts 121 and 122 and the connection part 13 was comprised by the plane which bend | folds perpendicularly | vertically on an outer peripheral surface and an inner peripheral surface.

FIG. 7 is a diagram showing _AL values and volumes of magnetic cores in the examples of the present invention and comparative examples.

Here, the A _L value is the number of turns expressed by A _L = L / N ² when a winding having N turns is wound around the core of the magnetic core and the inductance at both ends of the winding is L. It is an index for evaluating inductance without depending on it.

Although Example 1 has an _AL value equivalent to that of the comparative example, the volume of the magnetic core is small.

Further, in Examples 2 and 3, the _AL value is higher than that of the comparative example, and the volume of the magnetic core is further reduced.

  FIG. 8 is a diagram showing the coupling coefficient of the magnetic core in the example of the present invention and the comparative example.

  The coupling coefficient of the magnetic core is an index obtained by winding two windings around the core and calculating from the mutual inductance.

  In Example 1, the coupling coefficient was higher than that in the comparative example, and in Examples 2 and 3, the coupling coefficient was higher.

  From the results of FIGS. 7 and 8, the radii Rin, Rout and the thickness Th of the magnetic core satisfy the relationship of 0 <Rout ≦ Th + Rin, preferably Rin ≧ 0.2Th, more preferably Rin ≧ 0.4Th. If the relationship is satisfied, it can be seen that the inductance of the magnetic core can be improved while reducing the volume and weight of the magnetic core.

  FIG. 9 is a diagram showing the magnetic flux distribution of the magnetic core in the present invention. FIG. 9A shows the magnetic flux distribution when the radii Rin and Rout are both 0, and FIG. 9B shows the magnetic flux distribution when the radius Rin is 1.50 mm and the radius Rout is 4.00 mm. .

  9A shows a comparative example, and FIG. 9B shows the third embodiment.

  In FIG. 9A, the magnetic flux density at the outer peripheral corner portion at the boundary between the side core portions 121 and 122 and the connection portion 13 is very low and does not contribute to the inductance. Further, the inner peripheral corner portion of the boundary portion has a long magnetic path length and a high magnetic resistance despite a very high magnetic flux density.

  On the other hand, in FIG. 9B, since the outer peripheral corner portion of the boundary between the side core portions 121 and 122 and the connecting portion 13 also has a sufficient magnetic flux density, and the inner peripheral side of the boundary is also configured with a smooth curved surface, The magnetic path length is short. Therefore, as a whole, the magnetic resistance is lower than in FIG. 9A, and the inductance of the winding wound around the core portion 11 is improved.

  FIG. 10 is a diagram showing the relationship between the ratio of the total cross-sectional area of the side core part to the cross-sectional area of the core part of the magnetic core according to the present invention and the inductance value when wound around the core part.

  FIG. 10 shows the same tendency in any of Examples 1, 2, and 3.

  The ratio of the cross-sectional area of the two side core portions to the cross-sectional area of the middle core portion is desirably 220% or less for downsizing the choke coil, and 160% or more for ensuring the inductance. It is desirable. That is, when the cross-sectional area ratio is 160% or more and 220% or less, it is possible to achieve both the effect of improving the inductance and the effect of reducing the size of the entire choke coil.

  Since the ratio of the cross-sectional area is 160% or more and 220% or less, the inductance can be ensured even if the cross-sectional area of the core portion is reduced, so that the inner diameter and outer diameter of the gear bobbin can be reduced. As a result, the entire magnetic choke coil can be miniaturized.

  In addition, since the inner diameter of the gear bobbin can be reduced, the required winding length can be shortened even when a winding with the same number of turns as before is performed. It also becomes.

DESCRIPTION OF SYMBOLS 1 Magnetic core 2 Gear bobbin 3 Terminal block 11 Core part 12, 121, 122 Side core part 13 Connection part 21 Winding 31 Terminal N Number of turns W Width Lc Distance Lm Length Th Thickness To, Ts Height Rin Radius Rout Radius φ Diameter

Claims (6)

It is integrally formed and has a core part and left and right side core parts,
Furthermore, a magnetic core that constitutes a closed magnetic circuit by having a connection part that connects the end part of the core part and the side core part,
A separable gear bobbin having a gear part;
Windings,
A terminal block having terminals;
The gear bobbin is disposed in the core;
The winding is wound around the gear bobbin;
The magnetic core and the gear bobbin are disposed on the terminal block,
The choke coil, wherein an outer peripheral surface at a boundary between the side core portion and the connection portion forms a curved surface along a direction of magnetic flux generated by energization of the winding.   2. The choke coil according to claim 1, wherein an inner peripheral surface at a boundary between the center portion and the connection portion forms a curved surface along a direction of the magnetic flux. The inner peripheral surface is a curved surface having a radius Rin,
The outer peripheral surface is a curved surface having a radius Rout,
When the thickness of the side core portion in the direction facing the central core portion is Th,
The choke coil according to claim 2, wherein Rin ≧ 0.2Th and 0 <Rout ≦ Th + Rin.   The cross section perpendicular to the direction of the magnetic flux of the core portion is configured as a region surrounded by a closed curve including an arc centered on the central axis of the core portion. 4. The choke coil according to any one of 3. The magnetic core is ferrite;
The extending direction of the terminal is perpendicular to a plane including the middle core portion, the side core portion and the connection portion,
Having two side cores,
The side core portion is arranged so as to be arranged on both sides of the central core portion so that the magnetic core forms a Japanese character shape,
The sum of the cross-sectional areas perpendicular to the longitudinal direction of the two side core parts is 160% or more and 220% or less of the cross-sectional area perpendicular to the longitudinal direction of the middle core part. 4. The choke coil according to any one of 4. A set of two windings having the same number of turns,
The common mode choke coil according to claim 5, wherein common mode noise is absorbed or prevented by the set of windings.

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