JP2012119452A - Manufacturing method for reactor coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor coil excellent in productivity, and its manufacturing method as well as a reactor.SOLUTION: The manufacturing method for a reactor coil comprises: a winding process in which an element wire (bare element wire 1) composed of a conductor with no insulation coating having a cross section of other than a flat shape is wound spirally to form a standby coil 10; and a compression process in which a rectangular coil (bare rectangular coil 20) composed of the winding 2 whose element wire has a flat-shaped cross section obtained by compressing the standby coil 10 in an axial direction is formed. Since the winding of the element wire and the compression of the standby coil 10 are performed to the element wire with no insulation coating, damage in the insulation coating is prevented until the rectangular coil is formed.

Description

  The present invention relates to a reactor coil suitable for a reactor that constitutes a power conversion device such as an in-vehicle DC-DC converter, a manufacturing method thereof, and a reactor using the coil.

  A reactor is used as a component of a power converter that performs voltage step-up / step-down operation. For example, Patent Document 1 discloses a reactor configured by arranging a coil in a magnetic core. Specifically, a closed magnetic path that passes through a portion of the magnetic core (hereinafter referred to as the inner core portion) and a portion that covers the outside of the coil (hereinafter referred to as the outer core portion) is formed by exciting the coil. Is done. This coil for a reactor is an edgewise coil formed by edgewise winding a covered rectangular wire having an insulating coating formed on the surface of a conductor having a rectangular cross section. Since the edgewise coil can increase the space factor of the conductor as compared with a coil made of a winding having a circular cross section, the reactor can be made smaller.

JP 2009-033051

  However, when a coated rectangular wire is used as a winding, when forming an edgewise coil, it is necessary to keep the orientation of the front and back surfaces of the coated rectangular wire supplied to the coil molding machine constant, making the coil forming operation complicated. Become. Further, at the bent portion where the coated rectangular wire is bent, the thickness of the winding on the inner peripheral side tends to be thicker than that on the outer peripheral side of the bending. In addition, the coated rectangular wire having an insulating coating may damage the insulating coating during coil forming.

  In particular, when forming an edgewise coil with a coiled rectangular wire as a winding and having a rectangular end face outer shape, as shown in FIG. 6, there is a risk that the corner 50C of each turn constituting the coil 50 is displaced. .

  If the coil turns are formed by repeating the formation of the corners by bending the winding substantially at a right angle, the weight of the formed coil increases. Therefore, due to the inertia of the coil, the bending angle of the winding varies between when the winding connected to the coil with a small number of turns is bent and when the winding connected to a coil with a large number of turns is bent. In addition, when a coil having a large number of turns is formed by supplying a winding from a feeding bobbin to a coil forming machine, a difference in winding diameter of the winding on the feeding bobbin becomes large between the initial and final stages of winding. This difference in the winding diameter affects the wire rod of the wound winding wire, and appears as a difference in the amount of spring back depending on the corner portion, causing variations in the bending angle of the corner portion.

  On the other hand, the coil whose position of the corner of each turn is slightly shifted due to the variation in the bending angle is because the material of the conductor at the corner is work hardened to some extent. It is very difficult to correct.

  This invention is made | formed in view of the said situation, and the one of the objective is to provide the manufacturing method of the coil for reactors which is excellent in productivity.

  Moreover, the other object of this invention is to provide the coil for reactors manufactured by the manufacturing method of the coil for reactors of the said invention.

  Furthermore, another object of the present invention is to provide a reactor using the reactor coil of the present invention.

The manufacturing method of the coil for reactors of this invention is equipped with the following winding process and compression process.
Winding step: A spare coil is formed by spirally winding an element wire that does not have an insulating coating and is made of a conductor having a cross section other than a flat rectangular shape.
Compression step: The auxiliary coil is compressed in the axial direction to form a rectangular coil composed of windings in which the transverse cross section of the element wire has a rectangular shape.

  According to this method, since the preliminary coil is formed of a wire having a cross section other than a rectangular shape, when the wire is wound in a spiral shape, the direction of the outer periphery of the wire supplied to the coil forming machine is strictly There is no need to stipulate. In addition, since the winding of the wire and the compression of the spare coil are performed on the wire without insulation coating, and the insulation coating can be formed after the formation of the rectangular coil, the insulation coating is performed in the process until the rectangular coil is formed. The damage problem can be avoided. In addition, the cross-sectional shape of the winding forming the rectangular coil is determined not by the time of forming the preliminary coil, but by the plastic deformation of the cross-sectional shape of the wire due to the axial compression of the preliminary coil. The difference in the thickness of the winding hardly occurs between the inside and the outside. Furthermore, the bending form of the windings constituting the rectangular coil is tentatively determined when the spare coil is formed, and the spare coil is compressed to plastically deform the cross-sectional shape of the strand from a rectangular shape to a rectangular shape. Confirmed. Therefore, even when the end face outer shape of the flat coil is rectangular, it is easy to align the corners of each turn constituting the flat coil.

  As one form of the manufacturing method of the coil for reactors of this invention, the form to perform the said compression process using a metal mold | die is mentioned. Specifically, the inner periphery of the auxiliary coil is supported by the mandrel along the inner peripheral shape of the auxiliary coil, and the outer mold that forms the outer shape of the auxiliary coil after compression is arranged concentrically on the outer periphery of the mandrel. To do. Then, the auxiliary coil is compressed while being sandwiched between the upper die and the lower die that are fitted between the mandrel and the outer die.

  According to this method, the inner and outer circumferences and both end faces of the auxiliary coil can be appropriately supported and compressed by the respective molds, so that each turn can be plastically deformed substantially uniformly while maintaining the shape of the auxiliary coil. Thereby, it is easy to form the cross-sectional shape of the winding which comprises each turn of a flat coil uniformly.

  As one form of the manufacturing method of the coil for reactors of this invention, when performing a compression process using a metal mold | die, each of the said mandrel and an outer metal mold | die is divided into a plurality of mandrel division pieces and outer metal mold divisions that can be separated from each other radially The form provided with a piece is mentioned. The mandrel includes a diameter-expanding member that varies the outer size of the mandrel by varying the interval between the mandrel split pieces. The outer mold forms an inner peripheral surface adapted to the outer shape of the rectangular coil when the outer mold divided pieces are brought into contact with each other.

  According to this method, by making the mandrel in a state in which the interval between the mandrel split pieces is widened, the inner periphery of the spare coil can be supported by the mandrel at the time of compression, By doing so, the flat coil can be easily detached from the mandrel. Moreover, by using a split outer die, the outer die can be easily taken out by dividing and opening the outer die in the outer peripheral direction of the rectangular coil.

  As one form of the manufacturing method of the coil for reactors of this invention, the said winding process winds the said conductor so that the end surface shape seen from the axial direction of the said preliminary coil may become circular, and the said compression process includes the said end surface. The form which compresses with the shape maintained is mentioned.

  According to this method, a cylindrical rectangular coil can be easily formed.

  As one form of the manufacturing method of the coil for reactors of this invention, the said winding process winds the said conductor so that the end surface shape seen from the axial direction of the said preliminary coil may become a polygon, and the said compression process includes the said The form which compresses, maintaining an end surface shape is mentioned.

  According to this method, a rectangular tube-shaped rectangular coil can be easily formed.

  As one form of the manufacturing method of the coil for reactors of this invention, the form further provided with the coating process which forms an insulation coating in at least one part of the surface of the coil | winding which comprises the said flat coil.

  According to this method, since the insulating coating is formed after the rectangular coil is formed, the problem of damage to the insulating coating can be avoided in the process until the rectangular coil is formed.

  As one form of the manufacturing method of the coil for reactors of this invention, the said coating process includes the form which forms insulation coating by coating.

  According to this method, the insulating coating can be easily formed by coating the surface of the rectangular coil.

  As one form of the manufacturing method of the coil for reactors of this invention, the said coating process includes the form which forms insulation coating with a resin mold.

  According to this method, the insulating coating can be easily formed by covering the surface of the flat coil with the resin mold.

  On the other hand, the reactor coil of the present invention is obtained by the above-described method for manufacturing a reactor coil of the present invention.

  According to this configuration, it is possible to obtain a coil in which the difference in thickness is small between the inside and outside of the bending of the winding constituting the rectangular coil and the insulation coating is not substantially damaged. In particular, even in the case of a rectangular rectangular coil whose end face outer shape is a polygon, it can be a coil in which the corner portions of each turn are aligned. Therefore, when manufacturing a reactor combining the coil of this invention and a magnetic core, this assembly work can be made easy.

  The reactor of this invention is provided with the coil for reactors of this invention mentioned above, and the magnetic core by which this coil for reactors is arrange | positioned, It is characterized by the above-mentioned.

  Since the shape of the reactor coil according to the present invention is arranged, the shape of the reactor using the coil can be arranged. Moreover, since the coil for reactors of this invention can be used as a coil which does not have damage of insulation coating substantially, the reactor using the coil can fully ensure the insulation with a coil and a magnetic core.

  According to the method for manufacturing a reactor coil of the present invention, a rectangular coil having a well-shaped shape can be manufactured with high productivity. In particular, when manufacturing an edgewise coil having a polygonal end face shape, a rectangular coil having a small shape and a well-formed shape can be obtained.

  The reactor coil of the present invention can be a coil having a uniform shape and substantially free from damage to the insulation coating.

  The reactor of the present invention can ensure a sufficient insulation between the coil and the magnetic core, and can be a reactor with a well-formed shape.

It is explanatory drawing of the manufacturing method of the coil for reactors which concerns on embodiment. It is explanatory drawing of the metal mold | die and spare coil which are used for the method of embodiment. (A) is an explanatory view showing the mold shown in FIG. 2 before compression of the preliminary coil, (B) is an explanatory view showing the mold shown in FIG. 2 when the preliminary coil is compressed, and (C) is a mold shown in FIG. 2 after compression. It is explanatory drawing which shows. It is II sectional drawing of FIG. 3 (B). (A) is the schematic of the reactor which concerns on embodiment, (B) is a longitudinal cross-sectional view of (A). It is explanatory drawing which shows the position shift of the corner | angular part of a coil.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1
{Overview}
Here, the present invention will be described based on FIGS. 1 to 4 by taking a method of manufacturing a cylindrical edgewise coil as an example. This manufacturing method generally includes a winding process, a compression process, and a coating process. More specifically, each process is performed as follows (FIG. 1).
Winding step: A spare coil 10 is formed by winding a bare wire 1 having no insulation coating.
Compression step: The spare coil 10 is compressed to form a bare rectangular coil 20 composed of the rectangular winding 2.
Coating process: An insulating coating is formed on the surface of the bare rectangular coil 20 to form a coated rectangular coil.
Hereafter, the manufacturing method of this example is demonstrated in detail for every process.

{Winding process}
The winding step is a step of forming the spare coil 10 by winding the bare wire 1 having no insulating coating and having a flat cross section.

(Bare bare wire)
The bare wire 1 is a conductive wire having no insulation coating. By forming the spare coil 10 with the bare wire 1, it is possible to avoid the problem that the insulation coating is damaged when the spare coil is formed. As the material of the bare wire 1, a material having high conductivity can be suitably used. For example, copper, a copper alloy, aluminum, an aluminum alloy, etc. are mentioned. The cross-sectional shape of the bare wire 1 is other than a rectangular shape. For example, a circular shape and an elliptical shape are preferable. In particular, when the bare wire 1 is formed of a curved surface and does not have a flat surface, when the bare wire 1 is supplied to the coil forming machine for forming the spare coil 10, the same wire is used. Since it is not necessary to strictly define the direction of the outer peripheral direction of 1, it is preferable. In particular, a round wire having a circular cross section can be easily manufactured and handled and can be suitably used as the bare wire 1. In this example, a round wire made of copper is used for the bare wire 1. The diameter of the round wire is set to be larger than the thickness of the winding 2 constituting the bare rectangular coil 20.

(Winding condition)
Such bare wire 1 is spirally wound and formed into a spare coil 10 having a predetermined number of turns. Of course, this coil forming can be performed at room temperature, but since the bare wire 1 without insulation coating is the object to be processed, the bare wire 1 can be heated to an appropriate temperature. The heating temperature at this time can be selected in such a temperature range that the bending of the bare wire 1 is easier than at normal temperature, and the bare wire 1 is not excessively softened and disconnected. In this example, the bare wire 1 is wound at room temperature.

(Shape of spare coil)
The shape (end surface outer shape) of the end face of the auxiliary coil 10 viewed from the axial direction includes various forms such as a polygon having a rectangular shape as a representative example in addition to a circular shape and an elliptical shape. That is, as the shape of the auxiliary coil 10, either a cylindrical shape or a rectangular tube shape can be used. In this example, the outer shape of the end face of the auxiliary coil 10 is circular. Further, the pitch of the spare coil 10 can be selected with a wide likelihood. This is because the preliminary coil 10 is compressed in the compression step described later, and the bare rectangular coil 20 is formed at a pitch smaller than the pitch of the preliminary coil 10.

{Compression process}
The compression step is a step in which the auxiliary coil 10 is compressed in the axial direction to deform the cross-sectional shape of the bare wire 1 to form a bare flat coil 20 composed of the winding 2 having a flat cross-section. This compression is preferably performed using a mold so that the coil 10 can be compressed while maintaining the helical shape of the auxiliary coil 10. A compression process is demonstrated based on FIGS. 2-4 with the structure of a metal mold | die.

(Mold configuration)
The mold 30 includes a mandrel 31 and an outer mold 33 as shown in FIG. 2, and further includes an upper mold 35 and a lower mold 37 as shown in FIG.

<Mandrel>
The mandrel 31 is a member for supporting the inner peripheral side of the auxiliary coil 10 and molding the inner peripheral surface of the bare flat coil 20. Therefore, a bar having a cross-sectional shape matching the inner peripheral shape of the bare rectangular coil 20 can be used as the mandrel 31. In this example, a mandrel 31 having a circular cross section is used. The mandrel 31 is preferably of a split type in order to easily remove the bare rectangular coil 20 from the mandrel 31 after the spare coil 10 is compressed. In this example, a mandrel 31 including a mandrel segment piece 31P that is radially divided into four parts around the axis of the mandrel 31 and a diameter-expanding member 31B interposed between the segment pieces is used. Each divided piece 31P is configured by a rod-shaped body having a sector cross section. The number of divisions of the mandrel division piece 31P is not particularly limited.

  On the other hand, the diameter-expanding member 31B is inserted and removed between the mandrel segment pieces 31P, thereby changing the interval between the segment pieces 31P and making the outer diameter of the mandrel 31 variable. In this example, a plate member combined in a cross shape in accordance with the shape between the mandrel split pieces 31P is used as the diameter expanding member 31B. In a state in which the enlarged member 31B is interposed between the mandrel segment pieces 31P, the outer peripheral surface (a part of the cylindrical surface) of each segment piece 31P and the outer surface of the plate member constituting the enlarged member 31B are substantially continuous. A cylindrical curved surface is formed. The outer diameter of the mandrel 31 at that time is slightly smaller than the inner diameter of the spare coil 10 and substantially corresponds to the inner diameter of the bare rectangular coil 20. The number of plate members of the diameter-expanding member 31B may be appropriately selected according to the number of divisions of the mandrel division pieces 31P. Further, one end portion of the diameter-expanding member 31B is not a plane orthogonal to the longitudinal direction, but is formed in a mountain shape in which the thickness of each plate member decreases toward one end side. This is to facilitate insertion of the diameter-expanding member 31B between the mandrel split pieces 31P. In addition, the contact surface of the diameter-expanding member 31B with the mandrel split piece 31P is a flat surface in this example, but an appropriate number of holes may be provided in the plate material. This hole reduces the contact area between the plate material of the enlarged member 31B and the mandrel segment 31P, and reduces the friction between the both members 31P and 31B, making it easier to insert and remove the enlarged member 31B between the mandrel segments 31P. it can. In the insertion / removal operation of the diameter-expanding member 31B, the diameter-expanding member 31B is preferably driven by an appropriate actuator (not shown) such as a motor or a cylinder.

<Outer mold>
The outer mold 33 is a member that is disposed on the outer periphery of the auxiliary coil 10 and forms the outer peripheral surface of the bare flat coil 20. Therefore, a cylindrical member having an inner peripheral surface matched to the outer peripheral shape of the bare rectangular coil 20 can be used as the outer mold 33. The outer mold 33 is also preferably a split type so that the bare rectangular coil 10 can be easily taken out from the outer mold 33. In this example, the outer mold is constituted by the outer mold dividing pieces 33P radially divided into four equal parts. That is, each outer mold division piece 33P is formed of an arcuate curved piece. The number of divisions of the outer mold division piece 33P is not particularly limited.

  Further, the outer mold 33 is divided into a state in which each of the divided pieces 33P is formed between a state where each of the divided pieces 33P comes into contact with each other by a not-illustrated opening / closing mechanism and a state where the divided pieces 33P are separated from each other. Can be driven in the radial direction. This driving is also preferably performed by an opening / closing mechanism (not shown) including an appropriate actuator such as a motor or a cylinder. When the spare coil 10 is compressed, the divided pieces 33P are closed, and when the bare rectangular coil 20 is taken out, the divided pieces 33P are opened.

  The upper mold 35 and the lower mold 37 are members that compress the spare coil 10 disposed between the mandrel 31 and the outer mold 33 in the axial direction thereof. In this example, the upper and lower molds 35 and 37 are short cylindrical members that are interposed between the mandrel 31 and the outer mold 33 and are slid in the axial direction thereof. That is, the lower mold 37 supports the lower end surface of the preliminary coil 10 from below, and the upper mold 35 presses the upper end surface of the preliminary coil 10 downward. One of the upper mold 35 and the lower mold 37 may be slidable in the axial direction, or both may be slidable in the axial direction.

<Die usage procedure and operation>
The compression of the preliminary coil 10 is performed by combining the constituent members of the mold 30 as shown in FIG.

  First, the preliminarily molded preliminary coil 10 is prepared. Next, as shown in FIG. 3A, the mandrel 31 in which the diameter-expanding member 31B is inserted between the mandrel split pieces 31P in advance is fitted in the lower mold 37, and the mandrel 31 is placed. The spare coil 10 is fitted on the outer periphery of the.

  An outer mold 33 is disposed on the outer periphery of the spare coil 10. At this time, the outer mold division pieces 33P are brought into contact with each other to form the cylindrical outer mold 33. The outer mold 33 is arranged by operating an opening / closing mechanism (not shown) of the outer mold dividing piece 33P.

  Subsequently, as shown in FIG. 3B, the upper die 35 is inserted between the mandrel 31 and the outer die 33 from above the spare coil 10 to compress the spare coil 10. By this compression, the auxiliary coil 10 is compressed in the axial direction, and adjacent turns are pressed against each other. When the compression is further continued, the bare wire constituting the auxiliary coil 10 is plastically deformed. Since the outer periphery of the bare wire is constrained by the mandrel 31, the outer die 33, and the upper and lower dies 35 and 37, the cross-sectional shape of the bare wire is deformed from a circle to a rectangle.

  FIG. 4 shows the state in the mold at the end of the compression. Due to the deformation of the cross section of the bare wire, the reserve coil is formed into a bare flat coil 20 composed of the winding 2 having a rectangular cross section.

  After forming the bare rectangular coil 20, the upper die 35 is allowed to escape upward (see FIG. 3C), and the outer die 33 is opened to expose the bare rectangular coil 20. Next, the diameter-expanding member 33B is pulled out downward so that the mandrel split pieces 31P can be moved relative to each other. In this state, by moving the mandrel segment pieces 31P in a direction to bring them close to each other, a gap can be formed between the bare rectangular coil 20 and each mandrel segment piece 31P, and the bare rectangular coil 20 can be easily formed. The mandrel split piece 31P can be removed from the outer periphery. The bare rectangular coil 20 taken out is subjected to the next coating process.

{Coating process}
The coating step is a step of forming an insulating coating on the surface of the winding constituting the bare rectangular coil to form a coated rectangular coil. Specific examples of the means for forming the insulating coating include painting and resin molding.

(Painting)
The coating is formed so as to cover the entire circumference of the winding constituting the bare rectangular coil, thereby insulating the turns of the coil. Specifically, enamel coating, powder coating, and the like can be suitably used. Examples of the main component of the coating material include polyimide, polyamideimide, and epoxy. The thickness of the insulation coating by painting is preferably 20 μm or more and 100 μm or less, and the thicker the pinholes can be reduced and the insulation can be improved.

(Resin mold)
The resin mold is formed so as to cover the entire circumference of the winding constituting the bare rectangular coil, thereby insulating the turns of the coil. As the resin used for the resin mold, a resin excellent in insulation and heat resistance can be used. Specific examples include unsaturated polyester, epoxy, urethane, polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), and acrylonitrile-butadiene-styrene (ABS). This resin mold may be thinly formed on the surface of the winding so that the helical form of the coil can be recognized from the outside of the resin mold, or the coil helical form cannot be recognized from outside by connecting each turn with resin. You may do it. Specific examples of the latter include a resin mold having a cylindrical outer shape, or a resin mold in which a combination of a flat rectangular coil and a magnetic core, which will be described later, is collectively molded, and a resin mold having a shape substantially along the outer shape of the combination. And so on. In that case, the reactor is formed together with the formation of the insulating coating. The thickness of the insulating coating of the resin mold is equal to or greater than that of the above-described coating between turns, and the thickness of portions other than between the turns is often thicker.

(Bare flat coil when covered)
In any case of the above-described coating and resin molding, when forming the insulating coating, the coating or resin molding is performed in a state where the turn between the turns of the bare rectangular coil is widened. Normally, the turns of the bare rectangular coils are in contact with or close to each other due to compression in the compression process described above. Therefore, if painting or resin molding is performed in a state where the turns are widened, the coating material or resin of the resin mold is sufficiently filled between the turns, and insulation between the turns can be ensured. The interval between the widened turns is preferably narrow as long as the coating material or the resin of the resin mold can enter between the turns. If the interval between turns is excessively widened, the bare rectangular coil is plastically deformed in that state, and the axial length of the covered rectangular coil may be increased.

(Hardening of insulation coating)
The coating process includes a curing process of the formed resin coating. Regardless of whether the coating or the resin mold is used, the insulating film is made a film having sufficient hardness by curing the resin of the coating material or the resin mold. For example, in enamel coating, the coating is usually dried and cured by baking. A coated rectangular coil is formed by curing the insulating coating.

{Effect}
According to the above method for manufacturing a reactor coil, the following effects can be obtained.

  (1) Since the reserve coil is formed of a bare strand whose cross section is not a flat rectangular shape, the circumferential direction of the bare strand supplied to the coil forming machine is strictly determined when the bare strand is wound spirally. There is no need to stipulate. Therefore, it is excellent in the formability of the preliminary coil.

  (2) The winding of the bare wire and the compression of the spare coil are performed on the bare wire without insulation coating, and since the insulation coating can be formed after the bare rectangular coil is formed, until the bare rectangular coil is formed In this process, the problem of damage to the insulation coating can be avoided.

  (3) The cross-sectional shape of the winding forming the bare rectangular coil is determined not by the time of forming the spare coil but by the plastic deformation of the cross-sectional shape of the strands accompanying the compression of the spare coil in the axial direction. That is, the cross-sectional shape of the bare wire is deformed by compression in the substantially thickness direction of the winding. Therefore, a difference in the thickness of the winding hardly occurs between the inside and outside of the winding bending. As a result, it is possible to form a bare rectangular coil composed of windings having a uniform thickness over the entire length.

  (4) The bending form of the windings constituting the bare rectangular coil is provisionally determined when the preliminary coil is formed. When manufacturing a bare rectangular coil with a rectangular end face profile, it is easier to bend when round wires with the same cross-sectional area are wound than when winding a bare rectangular wire edgewise. Difficult to occur. The bending form of the windings constituting the bare rectangular coil is determined by compressing the spare coil and plastically deforming the cross-sectional shape of the bare strand into a flat shape. At that time, the bare wire is compressed in a state in which the shape of the spare coil is constrained by the mandrel, the outer die, and the upper and lower dies, and extends over the entire length of the winding including not only the winding bent portion but also the straight portion. Thus, the cross-sectional shape of the bare wire is deformed by plastic deformation. Therefore, when the end face of the bare rectangular coil is rectangular, even if there is some misalignment of the corner of the pre-compression pre-coil, the bent shape of the corner is substantially corrected along with the plastic deformation of the cross-sectional shape. It is thought that it will be confirmed. As a result, it is easy to align the corners of the turns constituting the bare rectangular coil, and it is possible to form a bare rectangular coil with a well-formed shape.

{Reactor}
Next, a reactor using the coated rectangular coil obtained by the above-described method will be described with reference to FIG.

  The reactor 100 includes the above-described coated rectangular coil 40 and a magnetic core 120 that forms a closed magnetic circuit by excitation of the coil 40. The magnetic core 120 can be divided into an inner core part 120 i mainly disposed inside the coil 40 and an outer core part 120 o covering the outer periphery of the coil 40. When a current is passed through the coil 40 of the reactor 100, a closed magnetic path passing through the inner core portion 120i and the outer core portion 120o is formed as shown by the arrow in FIG. Hereinafter, each constituent member other than the coil 40 in the reactor 100 and a method for manufacturing the reactor 100 will be described in order.

(Magnetic core)
As described above, the magnetic core 120 of the reactor 100 is divided into the inner core portion 120i and the outer core portion 120o. The inner core portion 120i and the outer core portion 120o 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 120i and 120o so that the relative permeability of the outer core portion 120o is smaller than the relative permeability of the inner core portion 120i. 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 120o” <“relative permeability of inner core portion 120i”, “saturation magnetic flux density of outer core portion 120o” <“saturation magnetic flux density of inner core portion 120i”. By adopting such a configuration, a compact reactor 100 is obtained with the same performance as compared with the case where the magnetic characteristics of both the core portions 120i and 120o are the same.

  The specific configurations of both core portions 120i and 120o of the magnetic core 120 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 120i (outer core part 120o) which employ | adopted the said 4th structure, this inner core part 120i (outer core part 120o) itself can be provided with the function to hold | maintain the coil 40. FIG. This is because when the inner core portion 120i (outer core portion 120o) is manufactured, the mixed fluid wraps around the outer peripheral surface of the coil 40, so that when the mixed fluid is cured, the inner core portion 120i (outer core portion 120o) and the coil This is because 40 is in close contact. Since the coil 40 is obtained by forming an insulation coating after forming a bare rectangular coil, the insulation coating has few defects, and the inner core portion 120i (outer core portion 120o) and the coil 40 are in close contact with each other. It doesn't matter at all.

  The above four configurations can be selected differently depending on the cores 120i and 120o. For example, the inner core portion 120i is produced with the dust core having the second configuration, and the outer core portion 120o is produced with the molded and cured body having the fourth configuration. In addition, since the laminated steel sheet of the first configuration generally has a high relative permeability and a low saturation magnetic flux density, the inner core portion 120i is formed from this laminated steel sheet, and the outer side is formed by the second, third, and fourth structures. The core part 120o may be formed. Alternatively, both the core portions 120i and 120o may be integrally formed in any of the second, third, and fourth configurations.

  Reactor 100 having the above configuration is used, for example, in a power conversion circuit of a hybrid vehicle. The energizing conditions for the automobile reactor are extremely severe conditions, with the maximum current (DC): 100 to 1000 A, the average voltage: 100 to 1000 V, and the operating frequency: 5 to 100 kHz. Even under such harsh conditions, the reactor 100 is expected to exhibit sufficient characteristics as a reactor for an automobile because the reactor 100 includes the coil 40 having an insulation coating with almost no defects.

(Reactor manufacturing method)
The reactor 100 is manufactured by arranging the inner core part 120i inside the prepared coil 40 and arranging the outer core part 120o outside the coil 40 so as to be connected to the inner core part 120i. Here, a case where both core parts 120i and 120o are different members will be described.

  The inner core portion 120i is prepared in advance with a dust core or a laminated steel plate, and an assembly in which the inner core portion 120i is housed in the coil 40 is manufactured. 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 part 120o with a dust core and arranging the coil 40 inside the outer core part 120o, the inner core part 120i is filled with a mixed fluid inside the coil 40. It may be produced.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration. For example, a rectangular coil in which two coils are arranged in parallel and connected by a part of a winding at one end thereof is subjected to molding and compression of a preliminary coil by a round wire as in the first embodiment. You can expect to get. In this case, as shown in FIG. 3 of Japanese Patent Application Laid-Open No. 2008-186980, it is preferable that the connecting portion connecting the two coils is formed in an S shape for the purpose of compressing the spare coil. Further, as shown in FIG. 2 of Japanese Patent Laid-Open No. 2008-028290, the pair of parallel coils may be combined with an annular magnetic core to form a reactor. In addition, even in a state where two coils including an inner coil and an outer coil are arranged coaxially, it can be expected to be obtained by forming and compressing a preliminary coil using a round wire as in the first embodiment. In this case, a cylindrical partition mold may be disposed between the inner spare coil and the outer spare coil.

  The manufacturing method of the coil for reactors of this invention can be utilized suitably for manufacturing the coil which comprises the reactor for vehicles. Further, the reactor coil obtained by this method and the reactor using the coil can be suitably used for a power conversion device of a vehicle such as a hybrid vehicle or an electric vehicle.

10 Spare coil
1 Bare wire
20 Bare rectangular coil
2 windings
30 mold
31 Mandrel 31P Mandrel split piece 31B Expanding member
33 Outer mold 33P Outer mold split piece
35 Upper mold
37 Lower mold
40 Coated flat coil
100 reactors
120 Magnetic core 120i Inner core 120o Outer core
50 Coil 50C Corner

Claims (10)

A winding step in which a preliminary coil is formed by spirally winding an element wire that does not have an insulating coating and whose cross section is made of a conductor other than a rectangular shape;
A method of manufacturing a reactor coil, comprising: a compression step of compressing the preliminary coil in an axial direction to form a rectangular coil including a winding having a rectangular cross section of the element wire. The compression step includes
Supporting the inner periphery of the auxiliary coil by a mandrel along the inner peripheral shape of the auxiliary coil;
An outer mold that forms the outer shape of the pre-compressed coil is arranged concentrically on the outer periphery of the mandrel,
2. The method for manufacturing a reactor coil according to claim 1, wherein the auxiliary coil is compressed while being sandwiched between an upper mold and a lower mold that are fitted between the mandrel and an outer mold. Each of the mandrel and the outer mold includes a plurality of mandrel split pieces and outer mold split pieces that can be separated from each other radially,
The mandrel includes a diameter-expanding member that can vary the outer size of the mandrel by making the interval between the mandrel split pieces variable,
3. The method for manufacturing a reactor coil according to claim 2, wherein the outer mold forms an inner peripheral surface adapted to an outer shape of the rectangular coil when the outer mold divided pieces are brought into contact with each other. . In the winding step, the wire is wound so that the end face shape of the auxiliary coil viewed from the axial direction is circular,
4. The method for manufacturing a reactor coil according to claim 1, wherein the compression step is performed while the shape of the end surface is maintained. In the winding step, the wire is wound so that the end surface shape viewed from the axial direction of the auxiliary coil is a polygon,
4. The method for manufacturing a reactor coil according to claim 1, wherein the compression step is performed while the shape of the end surface is maintained.   6. The method for manufacturing a reactor coil according to claim 1, further comprising a coating step of forming an insulating coating on at least a part of the surface of the winding constituting the rectangular coil. .   7. The method for manufacturing a reactor coil according to claim 6, wherein in the coating step, an insulating coating is formed by painting.   7. The method for manufacturing a reactor coil according to claim 6, wherein in the covering step, an insulating coating is formed by a resin mold.   A reactor coil obtained by the method for manufacturing a reactor coil according to any one of claims 1 to 8. The reactor coil according to claim 9,
And a magnetic core on which the reactor coil is disposed.

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