JP2012069598A - Reactor and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor in which defects are minimized in insulation coating of a coil.SOLUTION: In a reactor 1, an inner core section 20i is formed on the inside of a coil 10, an outer core section 20o is formed on the outside of the coil 10, and both core sections 20i and 20o are connected so that a closed magnetic path passing through both core sections 20i and 20o is formed when the coil 10 is excited. The coil 10 of the reactor 1 comprises a conductive linear conductor 10c wound spirally, and an insulation coating 10r covering the surface of the conductor 10c spirally along the winding shape thereof, and the insulation coating 10r is formed by electrodeposition coating.

Description

  The present invention relates to a reactor used as a component of a power conversion device that performs voltage step-up and voltage step-down operations, and a method for manufacturing the same.

  A reactor is used as a component of a power conversion device that performs a voltage step-up operation or a step-down operation. For example, Patent Document 1 discloses a reactor configured by arranging a coil in a magnetic core. In the case of this reactor, the excitation of the coil forms a closed magnetic path that passes through the portion of the magnetic core (hereinafter referred to as the inner core portion) and the portion that covers the outside of the coil (hereinafter referred to as the outer core portion). Is done.

JP 2009-33051 A

  However, in the reactor described in Patent Document 1, since the coil used to manufacture the reactor is formed by winding a winding having an insulating coating formed on the surface of the conductor, the insulating coating is damaged during winding. There is a fear. In particular, there is a possibility that defects such as cracking and peeling occur in the insulating coating on the inner side and the outer side of the bending radius of the bent portion. If the insulation coating is damaged in this way, conduction occurs between the coil conductor and the inner core portion or the outer core portion, and the magnetic characteristics of the reactor are deteriorated.

  This invention is made | formed in view of the said situation, and one of the objectives is to provide the reactor by which the defect in the insulation coating of a coil was suppressed, and its manufacturing method.

  In the reactor of the present invention, the inner core portion is formed inside the coil, the outer core portion is formed outside the coil, and both core portions are connected so that a closed magnetic path passing through both core portions is formed by excitation of the coil. It is a reactor. The coil of the reactor according to the present invention includes a conductive linear conductor wound in a spiral shape, and an insulation coating that covers the surface of the conductor spirally along the winding shape of the conductor. Is characterized by being formed by electrodeposition coating after winding a conductor in a spiral.

  According to the said structure, it can be said that it is a reactor in which defects, such as a crack and peeling, have hardly arisen in the insulation coating formed in the outer periphery of a coil. In the conventional configuration, a linear conductor having an insulation coating in advance is wound around the outer periphery. Therefore, an excessive bending stress acts on the insulation coating, and the bending stress causes a defect in the insulation coating. In contrast, in the configuration of the present invention, since the insulating coating provided on the outer periphery of the conductor is formed after the conductor is wound, bending stress does not act on the insulating coating in the first place. This is the reason why there is almost no defect in the insulating coating of the coil in the present invention.

  As one form of this invention reactor, it is preferable that an insulation coating contains an epoxy resin, a polyimide resin, or a polyamideimide resin.

  These epoxy resins, polyimide resins, and polyamideimide resins are water-soluble suitable for electrodeposition coating and have excellent insulating properties.

  As one form of this invention reactor, an outer core part is good also as a structure by which soft-magnetic powder is disperse | distributed in a nonmagnetic matrix.

  As shown in the embodiments described later, the inner core portion and the outer core portion can be configured to have different magnetic characteristics. In particular, it is preferable that the outer core portion has a lower relative permeability than the inner core portion. In that case, when the outer core portion is configured to disperse the soft magnetic powder in the matrix, the outer core portion optimized for the magnetic properties of the inner core portion can be obtained. This is because the configuration in which the soft magnetic powder is dispersed in the matrix is a configuration in which the relative permeability of the core portion can be easily changed by adjusting the ratio between the two.

  The manufacturing method of the reactor of the present invention is such that the inner core portion is formed inside the coil, the outer core portion is formed outside the coil, and both core portions are formed so that a closed magnetic path passing through both core portions is formed by excitation of the coil. It is a manufacturing method of a reactor for manufacturing a connected reactor. The method of manufacturing a reactor according to the present invention includes a coil preparation step of preparing a coil including a conductor wound in a spiral shape and an insulating coating spirally covering the outer periphery of the conductor along the winding shape of the conductor, And an assembling step of disposing the outer core portion outside the coil so as to be connected to the inner core portion. The coil preparation step further includes a coil forming step of spirally winding a linear conductor having conductivity, and a coating forming step of forming an insulating coating on the surface of the spirally wound conductor by electrodeposition coating And having.

  According to the method for manufacturing a reactor of the present invention, in preparing a coil provided in the reactor, the conductor is first wound and then the insulating film is formed so as to cover the outer peripheral surface of the wound conductor. This invention reactor provided with a coil without a defect can be produced.

  As one form of the manufacturing method of this invention reactor, it is preferable to wind a conductor so that a 5-300 micrometer clearance gap may be formed between the turns of the conductor wound helically in a coil formation process.

  By providing a gap between the turns of the wound conductor, in the coating forming step, an insulating coating can be formed in the outer peripheral surface of the conductor without leaving any part in the opposing portion between adjacent turns. In addition, it is possible to reliably suppress the formation of an insulating coating so as to connect adjacent turns by a predetermined gap, thereby making it possible that adjacent turns of a conductor are integrally molded with an insulating coating. Can be prevented.

  The reactor of the present invention is a reactor in which almost no defects are generated in the insulating coating of the coil provided in the reactor. Therefore, the reactor of the present invention has excellent magnetic characteristics and can be suitably used as a component part of a voltage conversion device in a hybrid vehicle, for example.

(A) is the schematic of the reactor which concerns on embodiment, (B) is the longitudinal cross-sectional view of (A), (C) is sectional drawing in the turn with a coil.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. The reactor of the embodiment is assumed to be a reactor that is used as part of a power conversion device that performs voltage step-up / step-down operations in a hybrid vehicle or the like.

<Embodiment 1>
[overall structure]
A reactor 1 shown in FIG. 1 includes a coil 10 formed by winding a winding and a magnetic core 20. The magnetic core 20 can be divided into an inner core portion 20 i mainly disposed inside the coil 10 and an outer core portion 20 o covering the outer periphery of the coil 10. When a current is passed through the coil 10 of the reactor 1, a closed magnetic path passing through the inner core portion 20i and the outer core portion 20o is formed as shown by the arrow in FIG. Hereinafter, each structure of this reactor 1 is demonstrated in detail, and the manufacturing method of the reactor 1 is demonstrated next.

(coil)
As shown in the cross-sectional view of FIG. 1C, the coil 10 includes a linear conductor 10c made of a conductive material wound in a spiral shape and an insulating coating 10r formed on the outer periphery of the conductor 10c. . As will be described later, the insulating coating 10r is wound around the conductor 10c by electrodeposition after the conductor 10c is wound in a spiral. Both ends 11 and 12 of the coil 10 are drawn from the magnetic core 20 as conductive terminals as shown in FIG.

  The conductor 10c provided in the coil 10 may be a linear body having conductivity according to the usage mode of the reactor 1, and the material and cross-sectional shape thereof are not particularly limited. As the material of the conductor 10c, for example, copper, copper alloy, aluminum, aluminum alloy, or the like can be used. Moreover, the cross-sectional shape of the conductor 10c may be a polygon including a rectangle or an ellipse including a circle.

  Further, the conductor 10c is wound spirally before the insulating coating 10r is formed on the outer peripheral surface thereof. The winding shape of the conductor 10c at that time is not particularly limited. Specifically, the conductor 10c is preferably wound so that the end face shape of the wound conductor 10c when viewed from the spiral axis direction is substantially circular, substantially elliptical, substantially rectangular, or racetrack. Here, the conductor (coil 10) illustrated in FIG. 1A is a conductor (coil 10) wound so that the end surface is substantially circular. In addition, if a rectangular wire (conductor 10c) having a rectangular cross section is wound edgewise, the conductor is wound so that the end surface is substantially rectangular.

  The entire outer peripheral surface of the wound conductor 10c (except for the vicinity of both end portions 11 and 12 serving as terminals of the coil 10) is covered with an insulating coating 10r formed after the conductor 10c is wound. The insulating coating 10r spirally covers the surface of the conductor 10c along the winding shape of the conductor 10c, and the insulating coating 10r facing each other between adjacent turns in the coil 10 is not integrated.

  The insulating coating 10r is formed by electrodeposition coating. This can be confirmed by examining the absorption or reflection spectrum in the insulating coating 10r by infrared spectroscopic analysis. Also, the fact that the insulating coating 10r is formed after the conductor 10c is spirally wound means that the insulating coating 10r is not distorted, for example, the insulating coating having a cross section obtained by cutting the conductor in the spiral diameter direction. The thickness can be confirmed by the fact that the outer side of the spiral is not thinner than the inner side and is uniform. Usually, if a conductor having an insulating coating is wound, the insulating coating is easily wrinkled particularly on the inner peripheral side of the bent portion, and the wrinkle is often visible.

  Examples of the main material of the insulating coating 10r include epoxy resin, polyimide resin, and polyamideimide resin. These resins are preferable in that they are suitable for electrodeposition coating and have excellent insulating properties. Further, the average thickness of the insulating coating 10r is preferably set to a thickness corresponding to the partial discharge start voltage in order to ensure insulation between turns of the coil 10.

(Magnetic core)
As described above, the magnetic core 20 of the reactor 1 is divided into the inner core portion 20i and the outer core portion 20o. The inner core portion 20i and the outer core portion 20o may be configured to have the same magnetic characteristics, or may be configured to have different magnetic characteristics. In the latter case, it is preferable to configure both the core portions 20i and 20o so that the relative permeability of the outer core portion 20o is smaller than the relative permeability of the inner core portion 20i. Here, in general, when the relative permeability increases, the saturation magnetic flux density also increases, and when the relative permeability decreases, the saturation magnetic flux density also decreases. That is, if “relative permeability of outer core portion 20o” <“relative permeability of inner core portion 20i”, “saturation magnetic flux density of outer core portion 20o” <“saturation magnetic flux density of inner core portion 20i”. By setting it as such a structure, it becomes the compact reactor 1 although it is the same performance compared with the case where the magnetic characteristics of both the core parts 20i and 20o are made the same.

  The specific configurations of the core portions 20i and 20o of the magnetic core 20 are roughly divided into the following four. First, a 1st structure is a structure which uses the laminated steel plate which laminated | stacked the several electromagnetic steel plate which has an insulating film.

  The second configuration is a configuration using a powder magnetic core obtained by press-molding a powder containing soft magnetic powder in which an insulating film is formed on the surface of soft magnetic metal particles, and firing the compact. It is. Fe or Fe alloy can be used as the soft magnetic metal particles, and phosphate or silicone resin can be used as the insulating film. The powder used for the production of the powder magnetic core may further contain a filler of nonmagnetic powder such as aluminum oxide, boron nitride or aluminum nitride, and the magnetic properties of the core portion can be controlled by the amount of the nonmagnetic powder. Can be changed.

  The third configuration is a configuration in which a powder containing soft magnetic powder is used as a core part as it is. For example, the core is provided with the third configuration by pressure-molding the powder but not firing. In addition, a core part having the third configuration can be obtained by preparing a case for holding the outer peripheral shape of the core part and filling the case with powder. In this third configuration as well, the powder may contain a filler.

  In the fourth configuration, a mixed fluid is prepared by mixing a powder containing soft magnetic powder similar to the second and third configurations in a nonmagnetic resin serving as a binder. It is the structure made into the shaping | molding hardening body obtained by hardening resin after making it into a molded object by cast molding etc. FIG. In this case, the molded cured body has a configuration in which soft magnetic powder is dispersed in a matrix made of a nonmagnetic resin. An epoxy resin, a phenol resin, a silicone resin, or the like can be used as the material of the nonmagnetic matrix. The nonmagnetic matrix may contain a nonmagnetic powder filler made of ceramic such as aluminum oxide or silica.

  By the way, if it is the inner core part 20i (outer core part 20o) which employ | adopted the said 4th structure, this inner core part 20i (outer core part 20o) itself can be given the function to hold | maintain the coil 10. FIG. This is because when the inner core portion 20i (outer core portion 20o) is manufactured, the mixed fluid wraps around the outer peripheral surface of the coil 10, so that when the mixed fluid is cured, the inner core portion 20i (outer core portion 20o) and the coil are mixed. This is because 10 closely contacts. Here, in the present invention, since there are few defects in the insulating coating 10r of the coil 10, there is no problem even if the inner core portion 20i (outer core portion 20o) and the coil 10 are in close contact with each other.

  The above four configurations can be selected as necessary. For example, the inner core part 20i is produced with the powder magnetic core which is the second structure, and the outer core part 20o is produced with the molded hardened body which is the fourth structure. Moreover, since the laminated steel plate which is the first configuration generally has a high relative permeability and a low saturation magnetic flux density, the inner core portion 20i is formed by this laminated steel plate, and the outer side is formed by the second, third and fourth configurations. The core part 20o may be formed. Alternatively, both the core portions 20i and 20o may be integrally formed in any of the second, third, and fourth configurations.

  Reactor 1 having the above configuration is used in a power conversion circuit of a hybrid vehicle. The energization conditions for the automotive reactor are maximum current (direct current): 100 to 1000 A, average voltage: 100 to 1000 V, and operating frequency: 5 to 100 kHz, which are very severe conditions. Even under such harsh conditions, the reactor 1 is expected to exhibit sufficient characteristics as a reactor for an automobile because it includes the coil 10 having an insulating coating with almost no defects.

[Reactor manufacturing method]
The reactor 1 is broadly divided into (1) a coil preparation for preparing a coil including a spirally wound conductor and an insulating coating 10r that spirally covers the outer circumference of the conductor along the winding shape of the conductor. And (2) an assembly step in which the inner core portion is disposed inside the prepared coil and the outer core portion is disposed outside the coil so as to be connected to the inner core portion. In the present invention, among these steps, the step (1) is characterized. Therefore, in the following description, step (1) will be described in detail, and step (2) will be briefly described.

(Coil preparation process)
The coil preparation step further includes a coil forming step for spirally winding a linear conductor having conductivity, and a coating formation step for forming an insulating coating 10r on the surface of the spirally wound conductor by electrodeposition coating. And comprising.

  In the coil forming step, the conductor 10c having the material and the cross-sectional shape already described is spirally wound by a winding machine. However, when winding the conductor 10c, a gap is created between the turns of the wound conductor 10c. This is because, when the insulating coating 10r is formed by electrodeposition coating on the outer peripheral surface of the wound conductor 10c in the coating forming step described later, the coating material wraps around the gap and is adjacent to the outer peripheral surface of the conductor 10c. This is because the insulating coating 10r is also formed on the opposing portions between the turns. The size of the gap formed between the turns is preferably 5 to 300 μm. If the gap is of this size, not only can the paint be introduced into the gap, but also the insulating coating 10r can be prevented from being formed so as to connect adjacent turns. On the other hand, when the insulating coating 10r is formed so as to connect adjacent turns, the entire wound conductor 10c is molded with the insulating coating 10r. In such a case, for example, when the conductor 10c is extended in the direction of the spiral axis by heat, that is, when the gap between turns is increased, the insulating coating 10r may be damaged.

  Next, in the coating forming step, an insulating coating 10r is formed on the surface of the conductor 10c wound spirally by electrodeposition coating. Electrodeposition coating is a method in which an object to be coated is placed in a water-based paint after the paint and the object to be coated are charged with different static electricity. The characteristic of electrodeposition coating is that a coating film having a uniform thickness can be formed as compared with solvent coating, and the uniformity of the thickness of the coating film is hardly influenced by the shape of the object to be coated. Therefore, a uniform coating film can be formed on the surface of the conductor 10c even if the conductor 10c has a three-dimensional shape wound spirally. The coating film becomes an insulating coating 10r through a drying and baking process.

  The thickness of the insulating coating 10r formed by one electrodeposition coating varies depending on the material of the paint. Therefore, if the insulating coating 10r having a desired thickness cannot be formed by a single electrodeposition coating, the electrodeposition coating may be performed a plurality of times so that the insulating coating 10r has a desired thickness. When performing the electrodeposition coating a plurality of times, the insulating coating 10r is not formed so as to connect the turns of the wound conductor 10c. However, since the insulating coating 10r formed by electrodeposition coating is very thin, if the gap between turns is set to 5 to 300 μm when the conductor 10c is wound, the insulating coating 10r that substantially connects the turns is formed. Not. In the next assembly process, when the coil 10 produced by forming the insulating coating 10r on the wound conductor 10c is combined with the magnetic core 20 to form the reactor 1, the coil 10 is compressed in the axial direction, etc. Thus, it is preferable that the turns are brought into close contact so that there is no gap between the turns of the coil 10. By compressing the coil 10 in the axial direction, the axial length of the coil 10 can be shortened, and as a result, the reactor 1 can be downsized. Moreover, the heat conduction in the axial direction of the coil 10 can be made smooth, and the heat dissipation of the reactor 1 can be enhanced.

  According to the coil preparation process including the coil forming process and the coating forming process described above, the insulating coating 10r formed on the outer periphery of the conductor 10c is hardly damaged. This is because the insulating coating 10r is formed on the outer peripheral surface of the conductor 10c after the conductor 10c is wound, so that bending stress when winding the conductor 10c does not act on the insulating coating 10r in the first place.

(Assembly process)
There are various variations in the assembling process depending on whether the inner core portion 20i and the outer core portion 20o are formed of the same member, separate members, or what members each core portion is formed of. Conceivable. As a typical procedure, a case where at least one of the core portions 20i and 20o is a molded cured body will be described below.

  First, the case where both the core parts 20i and 20o are made into the same member is demonstrated. In that case, it is good to form both the core parts 20i and 20o integrally with a shaping | molding hardening body. For example, the coil 10 is arranged in a mold, and a mixed fluid obtained by mixing a powder containing soft magnetic powder in a nonmagnetic resin is filled in a gap between the mold and the coil 10. And the reactor 1 by which the coil 10 was hold | maintained in the shaping | molding hardening body can be produced by hardening resin. Alternatively, a case that becomes a part of the reactor 1 may be prepared as a mold, the coil 10 may be disposed in the case, and a mixed fluid may be filled in a gap between the case and the coil 10. The coil 10 may be compressed in the axial direction so that there is no gap between the turns of the coil 10.

  Next, the case where the core parts 20i and 20o are different members will be described. In that case, the inner core part 20i is produced in advance with a dust core or a laminated steel sheet, and an assembly in which the inner core part 20i is housed inside the coil 10 is produced. And an assembly is arrange | positioned to the metal mold | die prepared separately, the said mixed fluid is filled in a metal mold | die, and resin is hardened. In addition, after manufacturing the bottomed cylindrical outer core portion 20o with a dust core and arranging the coil 10 inside the outer core portion 20o, the inner core portion 20i is filled with a mixed fluid inside the coil 10. It may be produced.

  According to the reactor manufacturing method described above, the reactor 1 shown in FIG. 1 can be manufactured.

  The embodiment of the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the gist of the present invention. For example, although the reactor 1 with reference to FIG. 1 has one coil 10, a plurality of coils 10 may be provided. In that case, in the magnetic core portion, a portion disposed inside each coil serves as an inner core portion, and a portion disposed outside each coil serves as an outer core portion.

  The reactor of the present invention can be suitably used as a component of a DC current booster circuit or a step-down circuit.

DESCRIPTION OF SYMBOLS 1 Reactor 10 Coil 11,12 Coil end part 10c Conductor 10r Insulation coating 20 Magnetic core 20i Inner core part 20o Outer core part

Claims (5)

An inner core portion is formed on the inner side of the coil, an outer core portion is formed on the outer side of the coil, and both core portions are connected so that a closed magnetic path passing through both core portions is formed by excitation of the coil,
The coil includes a conductive linear conductor wound spirally, and an insulating coating that covers the surface of the conductor spirally along the winding shape of the conductor,
The reactor is characterized in that the insulating coating is formed by electrodeposition coating after a conductor is wound spirally.   The reactor according to claim 1, wherein the insulating coating includes an epoxy resin, a polyimide resin, or a polyamideimide resin.   The reactor according to claim 1, wherein the outer core portion is formed by dispersing soft magnetic powder in a nonmagnetic matrix. To produce a reactor in which the inner core part is formed inside the coil and the outer core part is formed outside the coil, and both core parts are connected so that a closed magnetic path passing through both core parts is formed by excitation of the coil. A method of manufacturing the reactor of
A coil preparation step of preparing a coil including a conductor wound in a spiral shape and an insulating coating covering the outer periphery of the conductor spirally along the winding shape of the conductor;
And an assembly step of disposing the inner core portion inside the coil and disposing the outer core portion outside the coil so as to be connected to the inner core portion,
The coil preparation step further includes
A coil forming step of spirally winding a linear conductor having conductivity; and
A coating forming step of forming an insulating coating on the surface of the spirally wound conductor by electrodeposition coating;
The manufacturing method of the reactor characterized by having.   5. The method of manufacturing a reactor according to claim 4, wherein in the coil forming step, the conductor is wound so that a gap of 5 to 300 μm is formed between the turns of the spirally wound conductor.

Images