JP2010267768A - Reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor capable of being reduced in size, having high heat dissipating properties, and being equipped with a coil in which the terminal part is less apt to interfere by in a magnetic path. <P>SOLUTION: The reactor includes a core 2 made of a magnetic powder-mixed resin in which a magnetic powder is dispersed in a resin, and a coil 3 embedded in the core 2. The coil 3 has a wire-wound part 4, in which a flat cable 30 in a substantially rectangle cross sectional shape, is wound and a pair of terminal parts 5a, 5b provided upright from terminals 55, 56 of both terminals of the flat cable 30, in the winding axis direction of the wire-wound part 4 and projecting out of a terminal drawing face 2a of the core 2. The wire-wound part 4 includes an outside wire-wound part 42 wound in an outer circumference side, and an inside wire-wound part 41, continuing into the outside wire-wound part 42 at a terminal 51, at a side opposite to a side in which the terminal part 5 is upright-provided and wound in the inside of the outside wire-wound part 42. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reactor that hardly disturbs a magnetic path in a core and hardly reduces inductance characteristics.

Conventionally, as shown in FIG. 8, a core 95 made of a magnetic powder mixed resin in which magnetic powder is dispersed in a resin, a coil 91 embedded in the core 95, and a case 96 for housing the core 95 and the coil 91 are provided. A reactor 90 provided is known.
A perspective view of the coil 91 is shown in FIG. Thus, the coil 91 includes a winding portion 92 around which a conducting wire such as a flat wire is wound, and terminal portions 93 and 94 protruding from the upper surface 95a of the core 95 (see FIG. 8). The terminal portions 93 and 94 are taken out from the upper surface 95 a because they are blocked by the case 96 even if they are taken out from the side surfaces of the core 95.

  As shown in FIG. 9, the terminal 94 is such that the end of the conducting wire is drawn out from the coil bottom portion 92 b and passes through the side of the winding portion 92 so as to protrude from the upper surface 95 a of the core 95.

  Further, as shown in FIG. 10, in Patent Document 1 below, a round wire 97 is wound and reciprocated in the axial direction, so that two terminals are formed from one end 99 without forming the rising portion 94a (see FIG. 8). A reactor 90 'from which the sections 93' and 94 'are drawn out is disclosed.

JP 2006-4957 A

However, in the reactor 90 shown in FIG. 8, the rising portion 94 a of the coil 91 interferes with the magnetic path in the core 95, causing the inductance characteristics of the reactor 90 to deteriorate.
Therefore, there is a demand for a reactor that does not have the rising portion 94a and can pull out the two terminal portions 93 and 94 from one end of the coil 91.

  As shown in FIG. 10, the reactor described in Patent Document 1 is wound with a thin round wire 97 and reciprocated in the axial direction, so that two terminal portions 93 ′ and 94 ′ are taken out from one end portion 99. be able to. Therefore, there is no rising portion 94a (see FIG. 8), and the above problem does not occur.

However, since the reactor 90 ′ of FIG. 10 uses a round wire 97 having a circular cross section, a gap is easily formed in the coil 91 ′. Therefore, there is a problem that the space factor of the coil 91 ′ is low and the coil 91 ′ is likely to be large.
In addition, the coil 91 'has a problem that the space factor is low, the electric resistance is large, the heat is easily generated, and the heat dissipation is low.
Therefore, a reactor including a coil that can be reduced in size, has high heat dissipation, and does not easily interfere with the magnetic path of the terminal portion is desired.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a reactor including a coil that can be reduced in size, has high heat dissipation, and has a terminal portion that hardly interferes with a magnetic path.

The present invention is a reactor comprising a core made of a magnetic powder mixed resin in which magnetic powder is dispersed in a resin, and a coil embedded in the core,
The coil has a winding portion wound with a rectangular wire having a substantially rectangular cross section, and both ends of the rectangular wire are erected from one end portion in the winding axis direction of the winding portion and project from the core. And a terminal lead-out surface of the core from which the terminal part protrudes is formed on the one end side of the winding part,
The winding part is an outer winding part wound on the outer peripheral side;
An inner winding portion that is connected to the outer winding portion at an end opposite to the standing side of the terminal portion, and is wound inside the outer winding portion;
It is in a reactor characterized by providing (Claim 1).

The function and effect of the present invention will be described.
In the present invention, the reactor is formed using a two-layer coil including an outer winding portion wound with a rectangular wire and an inner winding portion located inside the outer winding portion. In this coil, terminal portions are erected in the same direction from the outer winding portion and the inner winding portion, respectively. Moreover, the outer side winding part and the inner side winding part are connected on the opposite side of the terminal part.
As a result, both the terminal portion of the outer winding portion and the terminal portion of the inner winding portion are pulled out from the end portion of the winding portion close to the core terminal extraction surface, and project from the terminal extraction surface of the core. I am letting. Therefore, the part which crosses a core can be made small about any of two terminal parts, and it can suppress that a terminal part obstructs a magnetic path. That is, it is not necessary to draw out the conducting wire from the bottom 92b of the winding portion 92 (see FIG. 8) and pass the rising portion 94a into the core 95 as in the conventional case, and the rising portion 94a does not cause a problem that obstructs the magnetic path. . Thereby, it can prevent that the inductance characteristic of a reactor falls.

Further, the present invention has an advantage that the heat dissipation of the coil is high. That is, in the present invention, since the coil is formed using a flat wire, it is difficult to form a gap in the coil as compared with the case where a round wire is used. Since there is an insulating resin having low thermal conductivity in the gap in the coil, if there are many gaps, the heat dissipation of the coil tends to decrease. When a coil is formed using a flat wire as in the present invention, the gap is reduced, and thus the heat dissipation of the coil can be improved.
In addition, when a coil is formed using a flat wire, a gap is less likely to be formed compared to a round wire, so that the coil volume can be reduced.

  As described above, according to the present invention, it is possible to provide a reactor including a coil that can be downsized, has high heat dissipation, and has a terminal portion that does not easily interfere with a magnetic path.

Sectional drawing of the reactor in Example 1. FIG. FIG. 3 is an exploded perspective view of the reactor in the first embodiment. The perspective view of the coil in Example 1. FIG. FIG. 3 is a partially enlarged perspective view of the reactor in the first embodiment. The expanded sectional view of the coil in Example 1. FIG. The manufacturing method explanatory drawing of the reactor in Example 1. FIG. The expanded sectional view of the coil in Example 2. FIG. Sectional drawing of the reactor in a prior art example. The perspective view of the coil in a prior art example. Sectional drawing of the reactor in the prior art example different from FIG.

A preferred embodiment of the present invention described above will be described.
In the present invention, the number of turns of the inner winding part is preferably smaller than the number of turns of the outer winding part.
If it does in this way, it can prevent that the magnetic flux density in a core becomes high locally. That is, in the above configuration, the inner cylinder in which the inner peripheral surface of the inner winding portion is extended from one end of the inner winding portion to the terminal lead-out surface of the core or from the other end to the surface opposite to the terminal lead-out surface. An outer cylindrical shape in which the outer surface of the outer winding portion extends from one end of the outer winding portion to the terminal lead-out surface of the core or from the other end to the surface opposite to the terminal lead-out surface of the core. When the surface So is compared, the areas of these cylindrical surfaces can be made substantially equal. Thereby, magnetic saturation in the vicinity of the inner cylindrical surface Si can be suppressed, and more magnetic flux Φ can be generated in the core. Therefore, the performance of the reactor can be improved.

Further, it is preferable that an insulating member is interposed between the outer winding portion and the inner winding portion.
If it does in this way, an outer side coil part and an inner side coil part can be insulated effectively. In the coil of the present invention, the potential difference between the outer winding portion and the inner winding portion tends to increase depending on the portion. Therefore, by interposing an insulating member between the outer winding portion and the inner winding portion, it is possible to effectively prevent dielectric breakdown between them.
In the present invention, the potential difference between the outer winding portion and the inner winding portion is increased in the vicinity of the terminal portion. Therefore, when the insulating member is partially provided, it is preferable to interpose the insulating member between the outer winding portion and the inner winding portion at a portion closer to the terminal portion.

Further, it is preferable that the rectangular wire is covered with an insulating coating, and the thickness of the insulating coating is determined so as to prevent a dielectric breakdown between the outer winding portion and the inner winding portion ( Claim 4).
If it does in this way, the dielectric breakdown between an outer side winding part and an inner side winding part can be prevented by the insulating film which has coat | covered the flat wire.

The coil is preferably composed of a single rectangular wire.
Although the outer winding portion and the inner winding portion may be formed as separate members and welded or the like, problems such as an increase in the number of manufacturing steps or a decrease in the reliability of the welded portion are likely to occur due to welding. If a coil is formed using a single rectangular wire as in this example, such a problem is less likely to occur.

Example 1
A reactor according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the reactor 1 of this example includes a core 2 made of a magnetic powder mixed resin in which magnetic powder is dispersed in a resin, and a coil 3 embedded in the core 2.
As shown in FIGS. 2 and 3, the coil 3 includes a winding portion 4 around which a rectangular wire 30 having a substantially rectangular cross section is wound, and both ends of the rectangular wire 30 at one end in the winding axis direction of the winding portion 4. It has a pair of terminal parts 5a and 5b which stand from the parts 55 and 56 and project from the core 2 (see FIG. 1). The terminal lead-out surface 2a of the core 2 from which the terminal portions 5a and 5b protrude is formed on one end portion 55 and 56 side of the winding portion 4.
The winding portion 4 is connected to the outer winding portion 42 at an outer winding portion 42 wound on the outer peripheral side and an end portion 51 (see FIG. 3) on the opposite side to the standing side of the terminal portion 5. And an inner winding portion 41 wound inside the winding portion 42.
The details will be described below.

  As shown in FIG. 1, in the reactor 1 of this example, the number of turns of the inner winding portion 41 is smaller than the number of turns of the outer winding portion 42. Therefore, as shown in FIGS. 1 and 4, the inner cylindrical surface Si that extends the inner peripheral surface 410 of the inner winding portion 41 to the terminal extraction surface 2 a of the core 2 or the bottom surface 2 b that is the opposite surface, and the outer When the outer peripheral surface 420 of the winding portion 42 is compared with the outer cylindrical surface So extending to the terminal extraction surface 2a of the core 2 or the opposite surface 2b, the areas of these cylindrical surfaces Si and So are substantially equal. It has become.

  In this example, as shown in the enlarged view of FIG. 5, the insulating member 6 is interposed between the outer winding portion 42 and the inner winding portion 41. The surface of the flat wire 30 is covered with a thin insulating film 7 (enamel).

  Next, the manufacturing method of the coil 3 of this example is demonstrated using FIG. First, a winding jig (not shown) is prepared, and one flat wire 30 is started to be wound from the winding start position 50 using this jig. Then, the rectangular wire 30 is wound up to the end portion 51 to form the inner winding portion 41. Next, the rectangular wire 30 is shifted outward at the end portion 51, and the insulating member 6 (see FIG. 5) is attached to the outer peripheral surface of the inner winding portion 41. Thereafter, the rectangular wire 30 is wound around the inner winding portion 41 via the insulating member 6 to form the outer winding portion 42. After the winding is finished, the terminal portion 5b is bent and erected.

  Moreover, when manufacturing the reactor 1, as shown in FIG. 6, the above-mentioned coil 3 is arrange | positioned in the case 8, and the terminal parts 5a and 5b are protruded upwards. Then, the core material 20 in which the magnetic powder is dispersed in the uncured thermosetting resin is poured into the case 8. Thereafter, heat treatment is performed at a predetermined temperature to cure the thermosetting resin of the core material 20. Thus, the reactor 1 shown in FIG. 1 is manufactured.

  Further, as shown in FIG. 1, the case 8 includes a bottom portion 8a and a wall portion 8b standing from the bottom portion 8a, and has an opening 80 opened on one side of the wall portion 8b. And the terminal extraction surface 2a is formed in the opening part 80 side. One side of the coil 3 in the axial direction faces the opening 80. The coil 3 is housed in the case 8 so that the central axis thereof is perpendicular to the terminal extraction surface 2a.

Next, the effect of the reactor 1 of this example is demonstrated.
In this example, as shown in FIG. 1, a two-layer coil 3 including an outer winding portion 42 around which a rectangular wire 30 is wound and an inner winding portion 41 located inside the outer winding portion 42 is provided. Reactor 1 was formed. In the coil 3, terminal portions 5a and 5b are erected from the outer winding portion 42 and the inner winding portion 41 in the same direction. Moreover, the outer side winding part 42 and the inner side winding part 41 are connected in the opposite side of the terminal parts 5a and 5b.
Thereby, both the terminal part 5b of the outer side winding part 42 and the terminal part 5a of the inner side winding part 41 are pulled out from the end parts 55 and 56 of the winding part 4 on the side close to the terminal extraction surface 2a. And projecting from the terminal extraction surface 2a of the core 2. Therefore, in any of the two terminal portions 5a and 5b, the portion that crosses the core 2 can be reduced, and the terminal portions 5a and 5b can be prevented from obstructing the magnetic path. That is, it is not necessary to draw out the conducting wire from the bottom 92b of the winding portion 92 (see FIG. 8) and pass the rising portion 94a into the core 95 as in the conventional case, and the rising portion 94a does not cause a problem that obstructs the magnetic path. . Thereby, it can prevent that the inductance characteristic of the reactor 1 falls.

In this example, there is also an advantage that the heat dissipation of the coil 3 is high. That is, in this example, since the coil 3 is formed using the flat wire 30, it is difficult to form a gap in the coil 3 as compared with the case where a round wire is used. Since insulating resin having low thermal conductivity is present in the gaps in the coil 3, if there are many gaps, the heat dissipation of the coil 3 tends to decrease. When the coil 3 is formed using the flat wire 30 as in this example, the gap is reduced, so that the heat dissipation of the coil 3 can be improved.
In addition, when the coil 3 is formed using the flat wire 30, it is difficult to form a gap as compared with the round wire, so that the volume of the coil 3 can be reduced.

In this example, as shown in FIG. 1, the number of turns of the inner winding portion 41 is smaller than the number of turns of the outer winding portion 42.
If it does in this way, it can prevent that the magnetic flux density in core 2 becomes high locally. That is, with the above configuration, the inner peripheral surface 410 of the inner winding portion 41 is opposite to the terminal extraction surface 2a of the core 2 from one end 55 of the inner winding portion 41 or the terminal extraction surface 2a from the other end 57. The inner cylindrical surface Si extending to the side surface 2b and the outer peripheral surface 420 of the outer winding portion 42 from one end 56 of the outer winding portion 42 from the terminal lead-out surface 2a of the core 2 or the other end 58 When the outer cylindrical surface So extended to the surface 2b opposite to the terminal extraction surface 2a is compared, the areas of the cylindrical surfaces Si and So can be made substantially equal. Thereby, magnetic saturation in the vicinity of the inner cylindrical surface Si can be suppressed, and more magnetic flux Φ can be generated in the core 2. Therefore, the performance of the reactor 1 can be improved.

Further, as shown in FIG. 5, in the reactor 1 of this example, the insulating member 6 is interposed between the outer winding portion 42 and the inner winding portion 41.
If it does in this way, the outer side winding part 42 and the inner side winding part 41 can be insulated effectively. In the coil 3 of this example, the potential difference between the outer winding portion 42 and the inner winding portion 41 tends to increase depending on the portion. Therefore, by interposing the insulating member 6 between the outer winding portion 42 and the inner winding portion 41, it is possible to effectively prevent dielectric breakdown between them.
Further, in this example, the potential difference between the outer winding portion 42 and the inner winding portion 41 is increased in the vicinity of the terminal portions 5a and 5b. Therefore, when the insulating member 6 is partially provided, it is preferable to interpose the insulating member 6 between the outer winding portion 42 and the inner winding portion 41 in a portion closer to the terminal portions 5a and 5b.

In this example, as shown in FIG. 3, the coil 3 is composed of a single rectangular wire 30.
The outer winding portion 42 and the inner winding portion 41 may be formed as separate members and may be welded. However, welding may increase the number of manufacturing processes or reduce the reliability of the welded portion. . If the coil 3 is formed using one flat wire 30 as in this example, such a problem is less likely to occur.

  As described above, according to this example, it is possible to provide the reactor 1 including the coil 3 that can be reduced in size, has high heat dissipation, and the terminal portion 5 hardly interferes with the magnetic path.

(Example 2)
In this example, the insulation method between the outer winding portion 42 and the inner winding portion 41 is changed. As shown in FIG. 7, in this example, the thickness of the insulating coating 7 covering the surface of the flat wire 30 is thicker than that of the first embodiment (see FIG. 5). Then, the thickness of the insulating coating 7 is determined so that the dielectric breakdown between the outer winding portion 42 and the inner winding portion 41 can be prevented.
If it does in this way, the dielectric breakdown between the outer side winding part 42 and the inner side winding part 41 can be prevented by the insulating film which coat | covers the flat wire 30. FIG.
In addition, the configuration and operational effects are the same as those of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Reactor 2 Core 3 Coil 4 Winding part 41 Inner winding part 42 Outer winding part 5 Terminal part 6 Insulating member 7 Insulating film

Claims (4)

A reactor comprising a core made of a magnetic powder mixed resin in which magnetic powder is dispersed in a resin, and a coil embedded in the core,
The coil has a winding portion wound with a rectangular wire having a substantially rectangular cross section, and both ends of the rectangular wire are erected from one end portion in the winding axis direction of the winding portion and project from the core. And a terminal lead-out surface of the core from which the terminal part protrudes is formed on the one end side of the winding part,
The winding part is an outer winding part wound on the outer peripheral side;
An inner winding portion that is connected to the outer winding portion at an end opposite to the standing side of the terminal portion, and is wound inside the outer winding portion;
The reactor characterized by providing.   2. The reactor according to claim 1, wherein the number of turns of the inner winding portion is smaller than the number of turns of the outer winding portion.   3. The reactor according to claim 1, wherein an insulating member is interposed between the outer winding portion and the inner winding portion.   4. The insulation film according to claim 1, wherein the rectangular wire is covered with an insulation film, and the insulation film is prevented from being broken between the outer winding part and the inner winding part. Reactor characterized in that the thickness of the is determined.

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