JP2015204406A - reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor in which the opposite ends of a conductor can be led out from the outer peripheral side of a core, while suppressing increase of eddy loss in the conductor.SOLUTION: A reactor includes a core 1 and a coil 2. The coil 2 includes two strip conductors, i.e., first and second conductors 21, 22 the ends of which are connected in parallel. The first conductor 21 and second conductor 22 form a first coil 2a by being wound and shaped like a pancake, in such a state that the second conductor 22 is arranged on one side in the thickness direction of the first conductor 21 while sandwiching an insulating layer, and form a second coil 2b by being wound and shaped like a pancake, in such a state that the second conductor 22 is arranged on the other side in the thickness direction of the first conductor 21 while sandwiching an insulating layer, on one side in the axial direction of the first coil 2a.

Description

  The present invention relates to a reactor suitably used for, for example, an electric circuit or an electronic circuit.

  A reactor is a passive element that uses a winding, for example, various electric currents such as prevention of harmonic current in a power factor correction circuit, smoothing of current pulsation in a current type inverter or chopper control, and boosting of a DC voltage in a converter. Used in circuits and electronic circuits.

  Also, in recent years, from the viewpoint of reducing environmental load, etc., the introduction of solar cells that can directly convert light energy into electric power without discharging carbon dioxide by using the photovoltaic effect has been promoted. For example, a solar power generation system is being introduced for residential use. Such a solar cell power generation system includes, for example, a solar cell module that converts solar light energy into electric power, and a power conditioner that converts DC power generated by the solar cell module into AC power in order to perform system linkage. And a distribution board that distributes the AC power converted by the power conditioner to various places in the house and to the electric power company. A reactor is usually used for the power conditioner.

  In addition, from the viewpoint of reducing the environmental load, etc., hybrid vehicles and electric vehicles (hereinafter collectively referred to as “environment-friendly vehicles”) capable of reducing carbon dioxide emissions have been researched and developed. Its spread is also being promoted. In such an environment-friendly vehicle, a booster circuit is used in the drive control system of the drive motor in order to improve the driving efficiency of the drive motor, and a reactor is usually incorporated in this booster circuit.

  For example, in Patent Document 1, a coil obtained by flatly winding a strip-shaped conductor having a thickness equal to or less than a skin depth corresponding to a driving frequency in a pancake shape is wrapped in a core portion, and a plurality of right and left ends of the innermost conductor of the coil A reactor that is folded and pulled out from the side surface of a core portion is disclosed.

  In Patent Document 2, a coil included in a core portion is laminated on a first coil portion obtained by winding a single strip-shaped conductor into a pancake shape and on one side in the axial direction of the first coil portion. The conductor is further provided with a second coil part obtained by winding the conductor into a pancake shape, and the outer ends of the first coil part and the second coil part are arranged from the outer peripheral side of the core part. A reactor that can be pulled out is disclosed. As a result, both ends of the belt-like conductor can be folded at a right angle, for example, and pulled out from the outer peripheral side of the core portion in a strip-like form without being folded several times, and the assembly process can be automated. ing.

Japanese Patent No. 4654317 JP 2011-138940 A

  However, in the reactor disclosed in the above-mentioned patent document 1, in order to draw out the conductor from the side surface of the core (leading out), the conductor is folded at right angles and a plurality of times, and machining with extremely low productivity (not suitable for automation) is performed. Must be done.

  On the other hand, in the reactor disclosed in Patent Document 2, it is not necessary to perform a plurality of processes such as folding, but the inductance (the number of turns) and the direct current resistance (cross-sectional area) are one pancake shape as in Patent Document 1. In order to maintain the same single-turn coil as described above, the thickness of the strip-shaped conductor must be increased, resulting in an increase in vortex loss in the conductor.

  An object of the present invention is to provide a reactor capable of pulling out both end portions of a conductor from the outer peripheral side of a core portion and suppressing increase in vortex loss in the conductor.

  The present invention is a reactor including a core portion and a coil included in the core portion, wherein the coil includes first and second coil portions stacked in the axial direction, and the first coil The two portions of the first and second conductors of the two strips whose ends are electrically connected in parallel at both ends are arranged in the longitudinal direction of the first conductor with the insulating layer in between. The second coil portion is formed by winding in a pancake shape with the second conductor disposed on one side, and the second coil portion insulates the remaining portion in the longitudinal direction of the first and second conductors. Provided is a reactor characterized in that it is formed by being formed into a pancake shape in a state where the second conductor is arranged on the other surface side in the thickness direction of the first conductor across a layer. .

  According to this, compared to a so-called single-winding coil in which, for example, one conductor is wound and formed into one pancake shape having the same diameter by stacking the first conductor and the second conductor in parallel. Although the number of turns is halved, the so-called double pancake winding in which the first coil portion and the second coil portion are formed is doubled in series, and the number of turns of the entire coil remains unchanged. On the other hand, the conductor cross-sectional area is also halved by double pancake winding as compared with the one formed by winding the one pancake coil, but it is doubled by two overlapping layers and remains unchanged.

  The first coil portion is formed by arranging a second conductor on one surface side in the thickness direction of the first conductor and winding it into a pancake shape, and the second coil portion is formed of the first conductor. The second conductor is disposed on the other surface side in the thickness direction and is formed by being wound into a pancake shape. Thereby, the induced electromotive forces generated in the respective conductors of the first coil portion and the second coil portion are canceled out, and thereby the eddy current is effectively suppressed.

  Further, both ends of the strip-shaped conductor can be pulled out from the outer peripheral side of the core portion without folding by double pancake winding, and the assembly process can be automated. In addition, since both ends of the conductor are collected on the outer periphery of the core, the conductor and the joint surface of the inner wall of the core can be simplified. Is done.

  In another aspect, the reactor further includes a disk-shaped magnetic member between the first coil portion and the second coil portion.

  According to this, there are the following effects. For example, when the width of the conductor is increased, distortion that makes the magnetic flux lines non-parallel to the axial direction tends to occur inside the coil. Therefore, by arranging a disk-shaped magnetic member between the first coil portion and the second coil portion as described above, the magnetic flux line on the outer diameter side recovers straightness in the axial direction, and the magnetic flux line Can suppress the occurrence of distortion that is not parallel to the axial direction.

  Thereby, for example, when the coil diameter is enlarged, the diameter of the core occupying most of the weight is increased and the diameter of the core portion is increased, which is against the weight reduction, but by expanding the conductor in the width direction in which the weight is difficult to increase, The reactor can increase the cross-sectional area of the coil and reduce the weight.

  In another aspect, in the reactor, the magnetic member has a thickness t and a gap s between the outer peripheral end of the magnetic member and the inner peripheral surface of the core so as to satisfy a condition of s ≧ t. It is formed.

  According to this, there are the following effects. For example, if the outer peripheral end of the magnetic member and the inner peripheral surface of the core part are too close, it becomes easy to generate a strain in which the magnetic flux lines are not parallel to the axial direction in the vicinity thereof. Therefore, as described above, when the gap s between the outer peripheral end of the magnetic member and the inner peripheral surface of the core portion is equal to or greater than the thickness t of the magnetic member, the above-described distortion is generated in the magnetic flux lines. It can suppress more effectively.

  In another aspect, in the reactor, the core portion and the magnetic member are made of a green compact that is an insulating film-coated metal powder and is hardened by pressing a ferromagnetic metal powder.

  According to this, since the green compact is isotropic and has a large specific resistance, eddy current loss generated in the core portion and the magnetic member is suppressed.

  In another aspect, in the reactor, the magnetic member is a wound iron core formed by winding a band-shaped soft magnetic material having a thickness equal to or less than a skin depth corresponding to a use frequency into a pancake shape with a second insulating layer interposed therebetween. It is characterized by being.

  According to this, the soft magnetic material used for the wound iron core is a ferromagnetic metal, for example, pure iron, iron-based alloy, and amorphous, but the width of the conductor compared to isotropic magnetic dust. Since the direction is anisotropic and the magnetic permeability is several tens to hundred times larger, the generation of the strain in the magnetic flux lines can be further suppressed and the thickness can be reduced (light weight). Further, since the specific resistance is large across the insulating layer, eddy current loss in the disk can be minimized.

  In another aspect, the reactor further includes a columnar pole piece disposed at a substantially central portion of the core portion, and the core portion has a hole for receiving the pole piece at the substantially central portion. The pole piece is arranged in the hole so that a gap can be formed between the inner periphery of the hole in the core portion and the outer periphery of the pole piece.

  According to this, the air gap of the magnetic circuit becomes a circle surrounding the pole piece. At this time, depending on the assembly error of the pole piece, there are a part where the gap is narrowed and a part where the air gap is widened. The inductance value is stabilized against variations). In addition, since the change in inductance causes the magnetic attraction force as it is, the vibration accompanying the change in the air gap due to the AC excitation does not essentially occur.

  In another aspect, in the reactor, the core part and the pole piece are formed of a green compact that is an insulating film-coated metal powder and hardened by pressing a ferromagnetic metal powder, and the density of the pole piece is It is characterized by being higher than the density of the core part.

  According to this, the pole piece in which the magnetic flux lines are concentrated and the magnetic flux density is higher than that of the core portion is made of a material having a higher magnetic permeability than the core portion, that is, a material having a higher density. The amount of magnetic flux leakage to the coil can be reduced, and eddy current loss in the coil conductor can be suppressed.

  In another aspect, in the reactor, the core portion includes a plurality of divided cores divided in a circumferential direction.

  According to this, the assembly of the coil mounting to the core portion is facilitated, and the coil heat generation can be directly released to the outside. In addition, it is possible to visually check the coil abnormality after assembly and operation.

  The reactor of the present invention can pull out both end portions of the conductor from the outer peripheral side of the core portion, and can suppress an increase in vortex loss in the conductor.

It is sectional drawing of the reactor of one embodiment of this invention. It is a schematic diagram of the coil used for the reactor of FIG. It is the graph which represented the skin depth (skin thickness) of various metal materials as a function of frequency. It is explanatory drawing before winding the 1st conductor and 2nd conductor which are used for the reactor of FIG. 1 to a winding frame. It is explanatory drawing of the state which started winding the 1st conductor and the 2nd conductor in the manufacturing method of a coil on a winding frame. It is explanatory drawing of the state in the middle of winding the 1st conductor and the 2nd conductor around a winding frame. It is a perspective view of the state which finished winding and forming the 1st conductor and the 2nd conductor to the winding frame. It is a perspective view of the state where a coil was stored in a core part. It is a figure which shows the equivalent circuit of the coil used for the reactor of FIG. It is a figure which shows the equivalent circuit of the coil of a comparative example. It is a principal part expanded sectional view of the reactor showing the magnetic flux diagram of the magnetic member used for the reactor of FIG. It is a principal part expanded sectional view of the reactor showing the magnetic flux diagram of the magnetic member of other embodiment. It is a principal part expanded sectional view of the reactor showing the magnetic flux diagram in the case of not providing a magnetic member. It is sectional drawing of the reactor of other embodiment. It is sectional drawing of the reactor of other embodiment. It is sectional drawing of the reactor of another another embodiment. It is sectional drawing of the reactor of other another embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a reactor according to an embodiment of the present invention.

  A reactor 10 according to this embodiment includes a core portion 1, a coil 2 included in the core portion 1, and a magnetic member 3.

  The core portion 1 is a member that passes a magnetic flux generated by a magnetic field generated in the coil 2 when the coil 2 is energized. In this embodiment, as shown in FIG. 1, the core portion 1 is a so-called pot type that encloses a coil 2, and the core portion 1 includes two first and second core members 1 a that face each other in the axial direction. 1b.

  In this embodiment, the first and second core members 1a and 1b have the same shape from the viewpoint of improving productivity, and the first and second core members 1a and 1b are respectively in the axial direction of the coil 2. The disk-shaped disk part 11 which covers the edge part of this, and the cylindrical part 12 extended substantially perpendicularly from the outer periphery of the disk part 11 are provided.

  These first and second core members 1a and 1b are made of a material having predetermined magnetic characteristics. In this embodiment, the 1st and 2nd core members 1a and 1b consist of a green compact (compact core) which pressurized and hardened insulating film covering iron powder. The soft magnetic powder used for the green compact is a ferromagnetic metal powder, for example, pure iron powder, iron-based alloy powder (for example, Fe-Al alloy, Fe-Si alloy, Sendust, Permalloy, etc.), or amorphous A powder is mentioned. Furthermore, as the insulating film coating covering the surface of the soft magnetic powder, a film made of an inorganic material such as an oxide, a film made of an organic material such as a silicone resin, or a double layer of an inorganic material and an organic material is combined. A film is formed.

  The first and second core members 1a and 1b can control the magnetic properties by the particle size and particle size distribution of the powder, and further the density of the molded body. For example, by increasing the density of the molded body, the magnetic permeability is increased. It is possible to suppress eddy current loss by reducing the particle size of the powder. Therefore, in order to realize the electromagnetic characteristics required for the reactor, the particle size of the powder used for the green compact and the density of the molded body are adjusted. In the case of pure iron powder, the density of the compact can be adjusted by adding the nonmagnetic powder material in the range of about 3.0 g / cc to about 5.0 g / cc, and about 5.0 g / cc to about 7 In the range of 0.7 g / cc, the pressure can be adjusted by molding.

  And the cylindrical part 12 of the 1st core member 1a and the cylindrical part 12 of the 2nd core member 1b are match | combined so that the core part 1 which has the coil accommodating part 13 inside by this can be formed.

  Further, the cylindrical portion 12 of the first core member 1a and the cylindrical portion 12 of the second core member 1b are opened at a predetermined depth from the end face of the cylindrical portion 12 so as to penetrate from the coil housing portion 13 to the outside. A lead hole 14 is provided.

  The coil 2 includes a first coil portion 2a and a second coil portion 2b stacked on one axial side (the upper side in FIG. 1) of the first coil portion 2a.

  The first coil portion 2a and the second coil portion 2b are formed by a strip-shaped first conductor 21 and a second conductor 22 whose end portions are connected in parallel.

In this embodiment, the first conductor 21 and the second conductor 22 have the same configuration and are made of, for example, aluminum having a predetermined thickness that is insulatively coated with an insulating material except for the both ends. This thickness is less than or equal to the skin depth (skin thickness) with respect to the drive frequency supplied to the reactor 10, and the eddy current loss can be further reduced. In general, the current flowing through the coil flows only in the range up to the skin depth, and the current does not flow uniformly throughout the conductor cross section. Therefore, eddy current loss can be reduced by setting the thickness of the conductors 21 and 22 to be equal to or less than the skin depth. The skin depth δ is generally δ = (ρ / πfμ) ^1/2 (where f: frequency, μ: magnetic permeability of the conductor member, ρ: electrical conductivity of the conductor member). FIG. 3 is a graph showing skin depth δ of various metal materials as a function of frequency.

  In addition, as shown in FIG. 4, the first conductor 21 and the second conductor 22 are, as shown in FIG. 4, one of the strip-shaped longitudinal portions serving as the first coil forming portions 21a and 22a, and the other longitudinal portion serving as the first portion. Two coil forming portions 21b and 22b are provided, and portions between the first coil forming portions 21a and 22a and the second coil forming portions 21b and 22b are connected portions 21c and 22c.

  The first coil forming portions 21a and 22a are wound in a pancake shape to form the first coil portion 2a. Moreover, the 2nd coil formation parts 21b and 22b are wound by pancake shape, and form the 2nd coil part 2b. The width and length of the second coil forming portions 21b and 22b are substantially the same as those of the first coil forming portions 21a and 22a.

  The connecting portions 21c and 22c connect the first coil forming portions 21a and 22a and the second coil forming portions 21b and 22b. In this embodiment, the connecting portions 21c and 22c have a width so as to form a predetermined angle α with respect to the longitudinal direction (XX direction) of the first coil forming portions 21a and 22a and the second coil forming portions 21b and 22b. It is bent in the direction (Y-Y direction) and extends from the first coil forming portions 21a, 22a to the second coil forming portions 21b, 22b. The widths of the connecting portions 21c and 22c are the same as those of the first coil forming portions 21a and 22a.

  Accordingly, the first coil forming portions 21a and 22a and the second coil forming portions 21b and 22b are separated from each other by a predetermined distance L2 in the width direction (YY direction). The distance L2 is larger than the width L1 of the first coil forming portions 21a and 22a and the second coil forming portions 21b and 22b.

  And these 1st conductors 21 and 2nd conductors 22 are wound and formed in the shape of a pancake as follows, and form the 1st coil part 2a and the 2nd coil part 2b.

  Specifically, as shown in FIG. 4, the first coil forming portions 21 a and 22 a and the second coil forming portions 21 b and 22 b of the first conductor 21 and the second conductor 22 are preliminarily attached to the temporary winding bobbin 51. Roll it up. Note that the winding directions of the first coil forming portions 21a and 22a and the second coil forming portions 21b and 22b around the temporary winding bobbin 51 are opposite to each other.

  Thereafter, the connecting portion 21c of the first conductor 21 is fixed to the cylindrical winding frame 52 from behind, while the connecting portion 22c of the second conductor 22 is fixed to the winding frame 52 from the front side. And fix. That is, the connecting portion 21 c of the first conductor 21 and the connecting portion 22 c of the second conductor 22 are fixed to the winding frame 52 so as to face each other in a cross shape via the winding frame 52.

  Then, as shown in FIGS. 5 and 6, the first coil of the second conductor 22 with insulation coating is formed on one surface 25 a in the thickness direction of the first coil forming portion 21 a of the first conductor 21 with insulation coating. The first coil forming portion 21a of the first conductor 21 and the first coil forming portion 22a of the second conductor 22 are unwound from the temporary winding bobbin 51 in a state where the portions 22a are arranged so as to overlap each other in the radial direction. Then, it is wound around the reel 52 in a pancake shape in the clockwise direction in the figure. Thereby, the pancake-shaped first coil portion 2a is formed.

  Further, the second coil forming portion 22b of the second conductor 22 is arranged on the other surface 25b side in the thickness direction of the second coil forming portion 21b of the first conductor 21, and the second coil forming portion of the second conductor 22 is formed. Each of the part 22b and the second coil forming part 21a of the first conductor 21 is wound around the winding frame 52 in a counterclockwise direction in the figure in a pancake shape while being unwound from the temporary winding bobbin 51.

  As a result, as shown in FIG. 7, a pancake-like second coil portion 2b is formed on one axial side of the first coil portion 2a (upper side in FIG. 7), and a double pancake coil 2 is obtained. It is done.

  Then, the end ends of the first coil forming portions 21a and 22a forming the first coil portion 2a are bent outward in the radial direction to form the first coil portion lead portion 26a, and the second coil portion 2b is formed. The end ends of the second coil forming portions 21b, 22b are bent outward in the radial direction to form the second coil portion lead portion 26b.

  These lead portions 26a and 26b need only be bent once outward in the radial direction, and can be easily manufactured. The folding may be performed after the entire amount has been wound. For example, the above-described temporary winding and holding bobbin 51 is provided with a slit for forming the lead portion in advance, and the first coil forming portion is provided in the slit for forming the lead portion. The end ends of 21a and 22a and the second coil forming portions 21b and 22b may be inserted and bent first. This is more preferable because the length of the lead-out portion and the accuracy of the bending amount are stabilized.

  Further, as shown in FIGS. 1 and 2, the first coil portion lead-out portion 26 a includes an end end of the first coil forming portion 21 a of the first conductor 21 and an end of the first coil forming portion 22 a of the second conductor 22. The ends are electrically connected in parallel by lead wires or the like. The second coil lead-out portion 26b is electrically connected in parallel between the end end of the second coil forming portion 21b of the first conductor 21 and the end end of the second coil forming portion 22b of the second conductor 22. Is done.

  As shown in FIG. 8, when the first core member 1a and the second core member 1b are combined with each other, the coil 2 formed in the double pancake winding is formed in the lead hole 14 of the first core member 1a. The second coil portion lead portion 26b is housed in the coil housing portion 13 so that the first coil portion lead portion 26a can be put into the lead hole 14 of the second core member 1b. In FIG. 8, the connection between the first conductor 21 and the second conductor 22 is omitted.

  Next, returning to FIG. 1, the magnetic member 3 will be described. The magnetic member 3 is for suppressing distortion that is not parallel to the axial direction of the magnetic flux lines. The magnetic member 3 of this embodiment is a disk-shaped magnetic member made of the same material as the core portion 1. It is configured. Specifically, the magnetic member 3 is made of a green compact that is an insulating film-coated metal powder and is formed by pressing and hardening a ferromagnetic metal powder.

  The magnetic member 3 is disposed between the first coil portion 2a and the second coil portion 2b. The magnetic member 3 is formed so that the thickness t is equal to or smaller than the gap s between the outer peripheral surface (outer peripheral end) of the magnetic member 3 and the inner peripheral surface of the core portion (s ≧ t).

  If the thickness t of the magnetic member 3 is formed to be the same as or smaller than the gap s as described above, the magnetic member 3 makes the axial direction of the magnetic flux line q on the outer diameter side of the coil 2 as shown in FIG. As a result, the effect of maintaining the straightness to the magnetic field increases, and the generation of distortion that is not parallel to the axial direction of the magnetic flux lines q can be effectively suppressed.

  The reactor 10 of the present invention configured as described above is formed by winding one conductor into two pancakes having the same diameter by overlapping two first conductors 21 and two second conductors 22 in parallel. The number of turns is halved compared to the coil, but the so-called double pancake winding is doubled in two stages in series, so that the number of turns of the entire coil remains unchanged. On the other hand, the conductor cross-sectional area is also halved by the double pancake winding, but is doubled by the parallel two-layer stacking and remains unchanged.

  Further, for example, when the second conductor 22 is arranged on one surface side in the thickness direction of the first conductor 21 and the first coil portion and the second coil portion are formed by winding, the first conductor as shown in FIG. 21 and the second conductor 22 form a loop, and the AC leakage magnetic flux line q2 passing therethrough generates an induced electromotive force p3 and an excessive eddy current flows, resulting in an increase in eddy loss. There is.

  However, in the present invention, the second conductor 22 is disposed on the one surface 25a side in the thickness direction of the first conductor 21, and is formed into a pancake shape to form the first coil portion 2a. The second conductor 22 is disposed on the other surface 25b in the thickness direction of the first conductor 21 so as to be laminated on one side in the axial direction of the coil portion 2a, and is formed by being wound into a pancake shape. The coil part 2b is formed.

  As a result, as shown in FIG. 9, the induced electromotive force p1 generated in the first conductor 21 and the second conductor 22 of the first coil portion 2a and the induction generated in the first conductor and the second conductor of the second coil portion 2b. The electromotive force p2 is canceled out, eddy current is effectively suppressed, and eddy loss can be suppressed.

  Further, both end portions of the strip-shaped conductors 21 and 22 can be pulled out from the outer peripheral side of the core portion 1 without being folded, and the assembly process can be automated. Moreover, by gathering both ends of the conductors 21 and 22 on the outer periphery of the core part 1, the conductors 21 and 22 and the joint surface of the inner wall surface of the core part 1 can be simplified, and a thinner and better thermal contact can be achieved. It becomes possible, and heat dissipation is remarkably improved.

  In the above embodiment, the reactor 10 has the magnetic member 3. However, for example, as shown in FIG. 14, the reactor 10 may not have the magnetic member 3. In this case, for example, if the first conductor 121 and the second conductor 122 constituting the coil 2 are made of copper, the specific resistance of copper (1.68 μΩcm) is smaller than the specific resistance of aluminum (2.65 μΩcm). When the same DC resistance is used, the width L2 of the first conductor 121 and the second conductor 122 can be made narrower than the width L1 (shown in FIG. 1) of the aluminum one. Therefore, even when it does not have the magnetic member 3, it is preferable at the point which can suppress the distortion | strain of the magnetic flux line of an outer diameter side.

  However, if the first conductor 121 and the second conductor 122 are made of copper instead of aluminum and have the same DC resistance, the weight becomes larger than that made of aluminum, and the weight of the vehicle can be reduced. It becomes difficult to meet the request. Therefore, as described above, it is preferable that the first conductor 121 and the second conductor 122 are made of a wide aluminum material and have the magnetic member 3 so as to reduce the weight of the magnetic flux lines. .

  In the above embodiment, the magnetic member 3 is formed such that the thickness t is equal to or smaller than the gap s between the outer peripheral surface of the magnetic member 3 and the inner peripheral surface of the core portion (s ≧ t ) Is not limited to this form, but can be changed as appropriate.

  For example, as shown in FIG. 12, the magnetic member 203 is formed so that the thickness t is larger than the gap s between the outer peripheral surface of the magnetic member 203 and the inner peripheral surface of the core portion 1 (s <t). Also good.

  In this case, the magnetic flux lines q are distorted as compared with the case of the condition of s ≧ t as in the above embodiment, but the magnetic flux lines on the outer diameter side of the coil 2 than in the case shown in FIG. q distortion can be suppressed.

  Moreover, in the said embodiment, although the magnetic member 3 was comprised from the green compact, it is not restricted to the thing of this form, It can change suitably. For example, as shown in FIG. 15, the magnetic member 303 is composed of a wound iron core formed by winding a strip-shaped soft magnetic body 303a having a thickness equal to or less than the skin depth corresponding to the operating frequency into a pancake shape with the second insulating layer interposed therebetween. You may have done.

  The soft magnetic body 303a used for the wound core is a ferromagnetic metal, and examples thereof include pure iron, iron-based alloy, and amorphous. Compared to an isotropic magnetic green compact, the anisotropy in the width direction of the coil and the magnetic permeability are several tens to a hundred times larger, so the effect of suppressing the distortion of the magnetic flux lines on the outer diameter side is great, and it can be made thin (lightweight). Further, since the specific resistance is large across the second insulating layer, eddy current loss in the disk can be minimized.

  Moreover, in the said embodiment, although the core part 1 was comprised from the cylindrical thing which does not have a hole in center part, it is not restricted to this form, It can change suitably. For example, as shown in FIG. 16, the core 401 may be formed of a cylindrical shape having a hole 401a at the center thereof, and a columnar pole piece 406 may be disposed in the hole 401a.

  Specifically, the pole piece 406 is a cylindrical body made of a green compact obtained by pressing and hardening an insulating film-coated iron powder, for example. The soft magnetic powder used for the green compact is a ferromagnetic metal powder, for example, pure iron powder, iron-based alloy powder (for example, Fe-Al alloy, Fe-Si alloy, Sendust, Permalloy, etc.), or amorphous A powder is mentioned.

  Further, the pole piece 406 has an outer diameter smaller than the inner diameter of the hole 401a of the core portion 401, and a gap 407 is formed between the outer peripheral surface of the pole piece 406 and the inner peripheral surface of the hole 401a of the core portion 401. Is formed.

  Thus, when the coaxial structure in which the pole piece 406 is disposed at the center portion of the core portion 401 is used, the magnetic circuit gap 407 becomes a circle surrounding the pole piece 406. At this time, depending on the assembly error of the pole piece 406, the gap 407 is narrowed and widened, but their contribution to the inductance cancels out, so that the variation in inductance becomes much more tolerant of assembly accuracy. Since the change in inductance causes a magnetic attraction force as it is, the vibration accompanying the change in the air gap due to the AC excitation can be essentially eliminated.

  In this case, it is preferable that the pole piece 406 in which the magnetic flux lines are concentrated and the magnetic flux density is higher than that of the core portion 401 is made of a material having a higher magnetic permeability than the core portion 401, that is, a high density. Thereby, the leakage magnetic flux line to the coil 2 can be reduced, and the eddy current loss in the coil 2 can be suppressed.

  Moreover, in the said embodiment, although the core part 1 was comprised from the 1st and 2nd core members 1a and 1b which have a disc part, it is not restricted to this form, It can change suitably. For example, as shown in FIG. 17, the core portion 501 may be composed of a plurality of divided cores 501 a (two are illustrated in FIG. 17) divided in the circumferential direction.

  If comprised in this way, the assembly of the coil 2 to the core part 501 will be easy, and the heat_generation | fever of the coil 2 can be directly escaped to the exterior. It is also possible to visually check the abnormality of the coil 2 after assembly or during operation.

DESCRIPTION OF SYMBOLS 1 Core part 2 Coil 2a 1st coil part 2b 2nd coil part 3 Magnetic member 21 1st conductor 22 2nd conductor

Claims (8)

A reactor including a core part and a coil included in the core part,
The coil includes first and second coil portions stacked in the axial direction.
The first coil portion includes one end portion in the longitudinal direction of the two strip-shaped first and second conductors whose ends are electrically connected in parallel at both ends, and the first conductor portion of the first conductor sandwiching an insulating layer therebetween. It is formed by winding and forming in a pancake shape with the second conductor arranged on one side in the thickness direction,
In the second coil portion, the remaining portion in the longitudinal direction of the first and second conductors is in a state where the second conductor is disposed on the other surface side in the thickness direction of the first conductor with an insulating layer interposed therebetween. A reactor characterized by being formed by being wound into a pancake.   The reactor according to claim 1, further comprising a disk-shaped magnetic member between the first coil portion and the second coil portion.   The magnetic member is formed so that a thickness t thereof and a gap s between an outer peripheral end of the magnetic member and an inner peripheral surface of the core portion satisfy a condition of s ≧ t. Item 2. Reactor.   4. The reactor according to claim 2, wherein the core part and the magnetic member are made of a green compact that is an insulating film-coated metal powder and is made by pressing and hardening a ferromagnetic metal powder. 5.   The magnetic member is a wound iron core formed by winding a band-shaped soft magnetic material having a thickness equal to or less than a skin depth corresponding to a use frequency into a pancake shape with a second insulating layer interposed therebetween. The reactor as described in any one of -4. A columnar pole piece disposed substantially at the center of the core part, further comprising:
The core portion includes a hole for receiving the pole piece in the substantially central portion;
The said pole piece is arrange | positioned in the said hole so that a clearance gap can be formed between the inner periphery of the hole in the said core part, and the outer periphery of the said pole piece. The reactor as described in any one. The core part and the pole piece are formed of a green compact obtained by pressurizing and solidifying a ferromagnetic metal powder, which is an insulating film-coated metal powder,
The reactor according to claim 6, wherein a density of the pole piece is higher than a density of the core portion.   The reactor according to any one of claims 1 to 7, wherein the core portion includes a plurality of divided cores divided in a circumferential direction.