JP2012015426A - Toroidal coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toroidal coil capable of reducing more in height in a finished state after a coil is wound around a toroidal core having a small diameter.SOLUTION: In a toroidal coil including a coil 30 formed by winding a winding wire 31 around a toroidal core 20, the toroidal core 20 has a cross-sectional shape of an isosceles trapezoid having an inner surface part shorter than an outer surface part.

Description

  The present invention relates to a toroidal type coil (toroidal coil) used for, for example, a choke coil or a line filter mounted on circuit wiring of a printed circuit board.

For example, various toroidal coils used for choke coils and line filters have been proposed in which windings (conductive wires) are continuously wound around a toroidal core (or a core cover containing the toroidal core) (for example, Patent Document 1 and Patent Document 2).
The toroidal coil has the advantage that most of the magnetic flux passes through the toroidal core itself, and has the advantage that there is little leakage magnetic flux and is not easily affected by surrounding objects. It is.

A conventional toroidal core generally has a rectangular shape in cross section although a small round is formed at a corner.
In addition, in a toroidal coil used for boosting, smoothing, or removing noise from a power supply circuit or the like, a current of about several A to 30 A flows, so a thick winding of about 0.5 mm to 2 mm is wound.

Japanese Utility Model Publication No. 6-55216 Japanese Utility Model Publication No. 61-55319

If the toroidal core is sufficiently large with respect to the required number of coil turns, the coil can be wound with one layer winding without overlapping the windings. However, in recent years, with the miniaturization of electric and electronic devices, Toroidal coils are also required to be small products.
For this reason, toroidal cores with smaller diameters and lower heights are used, and when the required number of turns of the coil is large or when the winding is thick, the required number of turns cannot be taken with one layer winding, and multiple windings are required. There are more cases that must be done.

  However, as shown in FIGS. 7 and 8, when the coil 131 is formed by winding the winding 131 around the conventional toroidal core 120 having a rectangular cross section, the inner circumference side and the outer circumference side of the toroidal core 120 are surrounded by the circumference. Since the length of the direction is different and the winding part is wide on the outer peripheral side and narrow on the inner peripheral side, as shown in the cross-sectional view of FIG. Even so, there is a problem that the windings 131b on the inner peripheral side overlap each other and the thickness increases, the thickness of the entire toroidal coil 110 becomes thick, and it is difficult to reduce the height.

  Therefore, the present invention realizes a toroidal coil capable of further reducing the finished state after the coil is wound around a small-sized (small-diameter) toroidal core so as to be compatible with electrical and electronic devices that are becoming smaller. It is for the purpose.

The first toroidal coil of the present invention is a toroidal coil comprising a toroidal core made of a magnetic material and a coil formed by winding a coil around the toroidal core, wherein the cross-sectional shape of the toroidal core is an outer surface portion, an inner surface Isosceles trapezoid (isosceles) formed by a portion, an upper surface portion, and a lower surface portion, wherein the outer surface portion and the inner surface portion are parallel, and the inner surface portion is shorter than the outer surface portion.
trapezium).

The first toroidal coil of the present invention is further characterized as follows:
“Having a core cover in which the toroidal core is housed, the winding is wound around the core cover, and the cross-sectional shape of the portion of the core cover around which the winding is wound is Isosceles
trapezium) ",
"The winding is wound in multiple layers in the inner surface portion than the outer surface portion, and the finished height of the coil in the outer surface portion and the inner surface portion is substantially equal."
“The difference in height between the outer surface portion and the inner surface portion is at least twice the diameter of the winding”,
Is included.

  Further, the second toroidal coil of the present invention is a toroidal coil comprising a toroidal core made of a magnetic material and a coil formed by winding a wire around the toroidal core, and the cross-sectional shape of the toroidal core is: It is formed of an outer surface portion, an inner surface portion, an upper surface portion, and a lower surface portion, and the angles formed by the outer surface portion, the upper surface portion, and the lower surface portion are both acute angles, and the inner surface portion is a trapezoid shorter than the outer surface portion. It is characterized by that.

The second toroidal coil of the present invention is further characterized as follows:
“Having a core cover in which the toroidal core is housed, the winding is wound around the core cover, and the cross-sectional shape of the portion of the core cover around which the winding is wound is It has a trapezoidal shape similar to the cross-sectional shape. ''
Is included.

  According to the toroidal coil of the present invention, the finished heights of the outer diameter side and inner diameter side windings can be made uniform, so that even a small (small diameter) can be reduced in height, and a small electric / electronic device Easy to implement.

It is a figure which shows the toroidal core which concerns on the example of 1st Embodiment of this invention, (a) is a top view, (b) is AA sectional drawing in (a). It is a figure which shows the state which wound the coil | winding to the toroidal core of FIG. 1, (a) is a top view, (b) is BB sectional drawing in (a). It is a figure which shows the core cover which accommodated the toroidal core which concerns on the example of 2nd Embodiment of this invention, (a) is a top view, (b) is CC sectional drawing in (a). It is a figure which shows the state which wound the coil | winding around the core cover which accommodated the toroidal core of FIG. 3, (a) is a top view, (b) is DD sectional drawing in (a). It is a figure which shows another example of the toroidal core which can be used for this invention, (a) is a top view, (b) is EE sectional drawing in (a). It is a figure which shows another example of the toroidal core which can be used for this invention, (a) is a top view, (b) is FF sectional drawing in (a). It is a figure which shows the toroidal core of a prior art example, (a) is a top view, (b) is GG sectional drawing in (a). It is a figure which shows the state which wound the winding to the toroidal core of FIG. 7, (a) is a top view, (b) is HH sectional drawing in (a).

  The toroidal coil of the present invention is a toroidal core wound with a winding or wound around a core cover containing a toroidal coil, and the toroidal core has a predetermined isosceles trapezoidal or trapezoidal cross section. Embodiments of the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows a toroidal core 20 according to this example, FIG. 1 (a) is a plan view, and FIG. 1 (b) is a cross-sectional view along the AA plane in FIG. 1 (a). 2 shows a toroidal coil 10A of this example in which the winding 31 is wound around the toroidal core 20 of FIG. 1, FIG. 2 (a) is a plan view, and FIG. 2 (b) is a view in FIG. 2 (a). It is sectional drawing in a BB surface.

The toroidal core 20 of this example has an annular shape (doughnut shape) in plan view, and the shape of the longitudinal section passing through the center of the circle is an isosceles trapezoid. More specifically, as shown in FIG. 1B, the cross-sectional shape is formed of an outer surface portion 21a, an inner surface portion 21b, an upper surface portion 21c, and a lower surface portion 21d, and the outer surface portion 21a and the inner surface portion 21b are parallel. The inner surface part 21b is an isosceles trapezoid shorter than the outer surface part 21a.
The toroidal core 20 is made of a magnetic material such as a MnZn ferrite material or a NiZn ferrite material.

When the inner circumferential side and the outer circumferential side of the toroidal core 20 have different circumferential lengths and the outer circumferential side is wide and the inner circumferential side is narrow, the winding 31a is aligned in a row on the outer surface 21a to form a coil with one layer winding. The winding 31b of the inner surface portion 21b overlaps with two or more layers.
At this time, since the cross-sectional shape of the toroidal core 20 is an isosceles trapezoid whose inner surface 21b is shorter than the outer surface 21a, the finished thicknesses of the outer and inner windings are made uniform (see FIG. 2B). .

More specifically, for example, a winding with a wire diameter of 1 mm is wound around a toroidal core having an outer diameter of 20 mm, an inner diameter of 10 mm, an isosceles trapezoidal outer surface portion 21 a shown in FIG. 1B and an inner surface portion 21 b of 6 mm. Then, since the inner peripheral length of the toroidal core is ½ of the outer peripheral length, when the winding is aligned and wound further on the outer surface portion 21a, the inner surface portion 21b has two layers of the winding (specific example 1). ).
In this case, the finished height of the outer and inner coils is the same as about 10 mm, and the outermost periphery of the winding is substantially rectangular.

On the other hand, a toroidal core having a conventional rectangular cross section (width 5 mm, height 7 mm) having the same outer diameter (20 mm), inner diameter (10 mm), and cross-sectional area (35 mm ² ) as that of the specific example 1, Similarly, when winding a wire with a wire diameter of 1 mm on the outer surface part and winding it one layer, the inner surface part has two layers of windings, and the finished height of the coil on the outer peripheral side is 9 mm (7 mm + 2 mm), The finished height of the inner peripheral coil is 11 mm (7 mm + 4 mm), and the height of the toroidal coil as a whole is 1 mm higher than that of the first specific example.

For example, when a winding having a wire diameter of 1 mm is wound around a toroidal core having an outer diameter of 24 mm, an inner diameter of 8 mm, an isosceles trapezoidal outer surface portion 21a shown in FIG. Since the inner circumferential length is 1/3 of the outer circumferential length, when the winding is aligned and wound further on the outer surface portion 21a, the inner surface portion 21b has three layers of windings (specific example 2).
In this case, the finished heights of the outer and inner peripheral coils are both about 12 mm, and the outermost periphery of the winding is substantially rectangular.

On the other hand, a toroidal core having a conventional rectangular cross section (width 8 mm, height 8 mm) having the same outer diameter (24 mm), inner diameter (8 mm), and cross-sectional area (64 mm ² ) as that of specific example 2, Similarly, when winding a wire having a wire diameter of 1 mm on the outer surface portion and winding it further, the inner surface portion has three layers of windings, and the outer coil has a finished height of 10 mm (8 mm + 2 mm), The finished height of the inner peripheral coil is 14 mm (8 mm + 6 mm), and the height of the toroidal coil as a whole is 2 mm higher than that of the second specific example.

  Thus, in the toroidal coil 10A of this example, the outer surface 21a and the inner surface 21b are parallel, and the inner surface 21b is shorter than the outer surface 21a. The finished heights of the side and inner circumference windings can be made more uniform, and even when a toroidal core having the same cross-sectional area as that of a conventional rectangular toroidal core is used, the height can be further reduced.

Further, as in the above specific example 1 and specific example 2, the difference in height between the outer surface portion 21a and the inner surface portion 21b is at least twice the wire diameter of the winding (double in specific example 1, four times in specific example 2). ), It is possible to suitably cope with the difference in the number of coil layers in the outer surface portion 21a and the inner surface portion 21b.
In addition, the number of coil layers in the outer surface portion 21a and the inner surface portion 21b is deeply related to the ratio of the outer diameter to the inner diameter of the toroidal core 20, so that the ratio of the outer diameter to the inner diameter as in the first specific example and the second specific example described above. By appropriately setting the height of the outer surface portion 21a and the inner surface portion 21b in consideration of the wire diameter of the winding, the finished height of the coils in the outer surface portion 21a and the inner surface portion 21b can be made the same, and the height can be reduced. Can be optimally designed.

(Second Embodiment)
FIG. 3 shows a core cover 40 containing a toroidal core according to this example, FIG. 3 (a) is a plan view, and FIG. 3 (b) is a cross-sectional view taken along the CC plane in FIG. 3 (a). is there. 4 shows the toroidal coil 10B of the present example in which the winding 31 is wound around the core cover 40 of FIG. 3, FIG. 4 (a) is a plan view, and FIG. 4 (b) is the view in FIG. 4 (a). It is sectional drawing in a DD plane.
In the toroidal coil 10B of this example, the toroidal core 20 of the first embodiment is housed in a core cover 40, and a winding 31 is wound around the core cover 40.

The core cover 40 includes a storage portion 40a made of an insulating resin and a lid portion 40b, and partition portions 42a and 42b that divide the outer periphery into two portions and divide the two winding portions 41a and 41b are formed. .
Grooves 43a and 43b for holding the partition plate 44 are formed in the partition portions 42a and 42b.
The partition portions 42a and 42b and the partition plate 44 are provided to separate the two coils 30 and 30 wound around the winding portions 41a and 41b from each other and to ensure a dielectric strength between them.

  The cross-sectional shape of the winding portions 41 a and 41 b around which the coil of the core cover 40 is wound is an isosceles trapezoid that is similar to the cross-sectional shape of the toroidal core 20. More specifically, as shown in FIG. 3B, the cross-sectional shape is formed by an outer surface portion 45a, an inner surface portion 45b, an upper surface portion 45c, and a lower surface portion 45d, and the outer surface portion 45a and the inner surface portion 45b are parallel. The inner surface 45b is an isosceles trapezoid shorter than the outer surface 45a.

Since the inner circumferential side and the outer circumferential side of the core cover 40 have different circumferential lengths and the outer circumferential side is wide and the inner circumferential side is narrow, the winding 31a is aligned in a row on the outer surface 45a to form a coil with one layer winding. The winding 31b of the inner surface part 45b overlaps with two or more layers.
At this time, since the cross-sectional shape of the core cover 40 is an isosceles trapezoid whose inner surface 45b is shorter than the outer surface 45a, the finished thicknesses of the outer and inner windings are made uniform (see FIG. 4B). .

  Thus, also in the toroidal coil 10B of this example, the finished heights of the outer and inner windings can be made more uniform, as in the toroidal coil 10A of the first embodiment. Even when a toroidal core having the same cross-sectional area as that of the toroidal core is used, the height can be further reduced.

Also, by making the difference in height between the outer surface 45a and the inner surface 45b of the core cover 40 more than twice the wire diameter of the winding, it is suitable for the difference in the number of coil layers in the outer surface 45a and the inner surface 45b. Can respond.
In addition, by appropriately setting the heights of the outer surface portion 45a and the inner surface portion 45b in consideration of the ratio of the outer diameter to the inner diameter of the core cover 40 and the wire diameter of the winding, the coil finish at the outer surface portion 45a and the inner surface portion 45b is achieved. The height can be made the same, and an optimal design with a low profile is possible.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that appropriate modifications and the like can be made without departing from the gist of the present invention.

  For example, the planar shape of the toroidal core and the core cover is not limited to a circle, and may be an ellipse or an ellipse as shown in FIG. The toroidal core 20A shown in FIG. 5 also has a cross-sectional shape formed by an outer surface portion 21a, an inner surface portion 21b, an upper surface portion 21c, and a lower surface portion 21d, the outer surface portion 21a and the inner surface portion 21b are parallel, and the inner surface portion 21b is formed. It is an isosceles trapezoid shorter than the outer surface portion 21a.

Further, the cross-sectional shape of the toroidal core and the core cover is not limited to an isosceles trapezoid, and may be a trapezoid as shown in FIG. The toroidal core 20B shown in FIG. 6 is formed of an outer surface portion 21aa, an inner surface portion 21bb, an upper surface portion 21cc, and a lower surface portion 21dd, and the angles formed by the outer surface portion 21aa, the upper surface portion 21cc, and the lower surface portion 21dd are the same. It is an acute angle, and the inner surface portion 21bb is a trapezoid shorter than the outer surface portion 21aa.
With such a trapezoidal shape, the finished heights of the outer diameter side and inner diameter side windings can be made uniform, and even a small (small diameter) can be reduced in height.

  Further, the cross-sectional shape of the toroidal core and the core cover is not limited to the above-mentioned complete isosceles trapezoid or trapezoid, and the corner may have a slight curvature as in the prior art. “Isopod trapezoid” and “trapezoid” include such things.

10A, 10B Toroidal coil 20, 20A, 20B Toroidal core 21a, 21aa Outer surface 21b, 21bb Inner surface 21c, 21cc Upper surface 21d, 21dd Lower surface 30 Coil 31 Winding 31a Outer winding 31b Inner winding 40 Core cover 40a Storage part 40b Cover part 41a, 41b Winding part 42a, 42b Partition part 43a, 43b Groove 44 Partition plate 45a Outer surface part 45b Inner surface part 45c Upper surface part 45d Lower surface part 110 Toroidal coil 120 Toroidal core 130 Coil 131 Winding 131a Winding on the outer peripheral side 131b Winding on the inner peripheral side

Claims (6)

In a toroidal coil comprising a toroidal core made of a magnetic material and a coil formed by winding a wire around the toroidal core,
The cross-sectional shape of the toroidal core is formed of an outer surface portion, an inner surface portion, an upper surface portion, and a lower surface portion, and the outer surface portion and the inner surface portion are parallel, and the inner surface portion is an isosceles trapezoid that is shorter than the outer surface portion. A toroidal coil characterized by that. Having a core cover in which the toroidal core is housed, and the winding is wound around the core cover;
2. The toroidal coil according to claim 1, wherein a cross-sectional shape of a portion of the core cover around which the winding is wound is an isosceles trapezoid similar to the cross-sectional shape of the toroidal core.   3. The toroidal according to claim 1, wherein the winding is wound in a multilayer in the inner surface portion than the outer surface portion, and the finished heights of the coils in the outer surface portion and the inner surface portion are substantially equal. coil.   The toroidal coil according to any one of claims 1 to 3, wherein a difference in height between the outer surface portion and the inner surface portion is at least twice the diameter of the winding. In a toroidal coil comprising a toroidal core made of a magnetic material and a coil formed by winding a wire around the toroidal core,
A cross-sectional shape of the toroidal core is formed by an outer surface portion, an inner surface portion, an upper surface portion, and a lower surface portion, and the angles formed by the outer surface portion, the upper surface portion, and the lower surface portion are both acute angles, and the inner surface portion is the outer surface. A toroidal coil characterized by a trapezoid shorter than the part. Having a core cover in which the toroidal core is housed, and the winding is wound around the core cover;
The toroidal coil according to claim 5, wherein a cross-sectional shape of a portion of the core cover around which the winding is wound is a trapezoid similar to the cross-sectional shape of the toroidal core.

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