JP2018133499A - Reactor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an outer peripheral shape of a dust core which can reduce the diameter of a coil portion while maintaining good magnetic characteristics.SOLUTION: A reactor includes a coil portion 20 in which a flat wire is wound in an edgewise winding manner and core portions 10A and 10B that is composed of a dust core around and in which the coil portion 20 is wound around central leg portions 13A and 13B, and in parts of the core portions 10 around which the coil portions 20 are wound, ridgeline portions opposed to inner peripheral portions 21 of the coil portions 20 have shapes of stepped portions 23B1 and 23B2 each of which is cut off by a plane so as to be along the inner peripheral portion 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reactor mounted on, for example, an electric vehicle or a hybrid vehicle, and a manufacturing method thereof. More specifically, the present invention relates to a reactor in which a coil is inserted into a part of a core constituting a magnetic path and a manufacturing method thereof. .

In recent years, in magnetic elements such as reactors, a technique for forming a powder magnetic core (dust core) into an arbitrary shape by press molding has been widely known.
This type of magnetic element is configured by winding a coil around a part of a core that constitutes a magnetic path, and the core is generally formed in a prismatic shape (see Patent Document 1 below). Since the ridge line portion is easily in contact with the inner peripheral portion of the coil, the coil tends to have a large diameter for safety.
In addition, when the current of the battery is increased, a high withstand voltage is required between the core and the coil, such as ensuring the distance between the core and the coil, and ensuring the withstand voltage by sandwiching an insulator between the core and the coil. Countermeasures have become necessary, and this also increases the diameter of the coil.
It is desirable from the viewpoint of recent demand for component miniaturization and material reduction that the inner periphery of the coil and the outer periphery of the core are arranged as close as possible and with a slight gap that can maintain insulation. .

  On the other hand, the core composed of the dust core has a pressing direction (a direction in which the granular structure is compressed and flattened) set to a direction perpendicular to the magnetic path plane, so that the direction in which the magnetic flux flows and the shape of the magnetic particles Since the major axis directions coincide with each other, the initial L value (inductance) and the BH characteristics in the low to medium magnetic flux region are improved particularly in a pure iron-based dust core.

JP 2000-77249 A

  However, in a core made of a dust core, when the pressing direction is set to a direction orthogonal to the magnetic path plane, the ridge line (corner) of the core is formed in an R shape along the inner periphery of the coil. It was difficult to do in theory of press molding.

  The present invention has been made in view of such circumstances, and in the case of a core composed of a dust core, the coil direction is set to a direction orthogonal to the magnetic path plane to improve the magnetic characteristics. It is an object of the present invention to provide a reactor that can be made into the outer peripheral shape of a core for reducing the diameter of the portion, and a manufacturing method thereof.

In order to solve the above problems, a reactor according to the present invention is:
A coil section;
A core portion that is formed into a predetermined magnetic path shape using a dust core, and the coil portion is inserted around a part of the magnetic path shape,
In the portion of the core portion around which the coil portion is wound, the ridge line portion facing the inner peripheral portion of the coil portion is cut into a shape that is cut off with a flat surface along the inner peripheral portion. To do.

Moreover, it is preferable that the particle shape of the powder magnetic core which comprises the said core part is made into the shape compressed in the direction orthogonal to a magnetic path plane.
Moreover, it is preferable that the corner | angular part of the ridgeline facing the inner peripheral part of the said coil part is cut off in step shape.

Moreover, it is preferable that the said step part has four step parts which oppose the radial direction of the said coil part.
Furthermore, it is preferable that the core portion has a configuration in which leg portions of two E-shaped partial cores are abutted with each other, and the coil portion is inserted through a middle leg portion of the E-shaped partial core.

Moreover, the method for manufacturing the reactor according to the present invention is as follows.
A core part is formed by combining partial cores formed by compressing a dust core in a direction perpendicular to the magnetic path plane,
Around the part of this core part, arrange the coil part that passes through this core part,
When forming the partial core, the ridge line portion of the partial core facing the inner peripheral portion of the coil portion is cut into a shape with a flat surface so as to follow the inner peripheral portion. is there.

According to the reactor and the manufacturing method thereof of the present invention, the following operational effects can be achieved.
The ridge line part of the prismatic core part facing the inner peripheral part of the coil part is cut off with a flat surface along the inner peripheral part, so that the outermost part of the core part, in particular, the most protruding part Since the height of the ridgeline part to comprise can be reduced and a space can be provided between the outer peripheral part of a core part and the inner peripheral part of a coil part, a coil part can be reduced in diameter. Thereby, the reactor can be made compact and the forming material can be made more efficient.

  In addition, the ridgeline part of the core part may be molded by a flat surface, and it is possible to perform molding press in the direction where the characteristics are improved, so the initial L value is reduced in the pressing direction and the BH characteristics are degraded in the low to medium magnetic flux range. It can be set as the direction which can prevent.

It is a perspective view which shows the positional relationship of the core part and coil part of the reactor which concern on embodiment of this invention. It is a perspective view which shows the core part of the reactor which concerns on embodiment of this invention. It is the perspective view (A) and partial cross section (B) which show the whole structure of the reactor which concerns on embodiment of this invention. It is the perspective view (A) and sectional perspective view (B) which show the positional relationship of the core part and coil part of the reactor which concern on the modification 1 of this invention. It is the perspective view (A) and sectional perspective view (B) which show the positional relationship of the core part and coil part of the reactor which concern on the modification 2 of this invention. It is the perspective view (A) and sectional perspective view (B) which show the positional relationship of the core part and coil part of the reactor which concern on the modification 3 of this invention. It is explanatory drawing (A) which shows the difference of the press direction of an Example and a comparative example, and the graph (B) which shows a BH characteristic. It is a graph which shows the direct current | flow superimposition characteristic of an Example and a comparative example.

  Hereinafter, a reactor according to an embodiment of the present invention will be described with reference to FIGS.

<Main reactor configuration>
As shown in FIGS. 1 and 2, the main part of the reactor 1 according to one embodiment of the present invention includes E-shaped partial cores 10 </ b> A and 10 </ b> B, leg portions (left and right leg portions 11 </ b> A, B, 12 </ b> A, and B). The middle leg portions 13A, B) are arranged so that the tips of the middle legs 13A and B are abutted with each other. The outer legs of the positions where the middle legs 13A and B are abutted with each other are formed of an air-core coil formed by winding a rectangular wire. The coil part 20 is inserted.
In the middle legs 13A, B of the partial cores 10A, B, the ridge line portions facing the inner peripheral portion 21 of the coil portion 20 are stepped portions 23A, B, and the outer peripheral portions of the partial cores 10A, B are The coil portion 20 is positioned so as not to come into contact with the inner peripheral portion 21 of the coil portion 20 and not to be too far away. That is, the distance of the outer peripheral part of each partial core 10A, B with respect to the inner peripheral part 21 of the coil part 20 is made into the state equalized to some extent.

  FIG. 3A shows the overall appearance of the reactor 1. However, the partial cores 10A and B are not shown because they are covered with other members. Specifically, each of the partial cores 10A and B is covered with bobbins 40A and B that maintain insulation between the coil portions 20 and the like. Further, the bobbins 40A and B are abutted against each other in a state of covering the partial cores 10A and B (abutted, the tips of the leg portions are not covered), and project outwardly at the corners. Overhang portions 42A, B, C, and D are provided.

The aluminum case 50 is adapted to accommodate the bobbins 40A and B assembled as described above.
The inner wall faces the outer surfaces of the bobbins 40A and B, and the bobbins 40A and B are accommodated inside the case 50 without play.

  The overhanging portions 42A, B, C, and D of the bobbins 40A and B are formed with through holes (not shown), and the screws 60A, B, C, and D are formed through the through holes and the bottom of the case 50. It is screwed into the stepped parts 54A, B, etc. that rise from the top (see FIG. 3B). That is, as shown in FIG. 3B in which only a part of FIG. 3A is shown, the screws 60A, B, C, and D penetrating through the through holes are stepped up from the bottom of the case 50 54A, B and the like, and by screwing in the screws 60A, B, C, D, the bobbins 40A, B are pushed down toward the bottom of the case 50, and the middle legs 13A The lower end surfaces of the bobbins 40A and B, which are parts covering B, press the inner peripheral surface of the coil portion 20 downward, and the lower outer peripheral surface of the coil portion 20 is pressed against the upper surface of the heat transfer sheet 30. Become. Thereby, the heat generated in the coil portion 20 can be efficiently released to the outside through the heat transfer sheet 30.

The heat transfer sheet 30 faces a heat sink (not shown) through the bottom wall portion of the case 50, and the heat transferred to the heat transfer sheet 30 is released from the heat sink to the outside.
Further, as described above, according to the reactor 1 of the present embodiment, the overhanging portions 42A, B, C, and D that project outward are provided at the respective corners inside the case 50, and the screws 60A, B, and C are provided. , D is secured.
Accordingly, in order to secure a space for arranging the overhanging portions 42A, B, C, D, in each of the partial cores 10A, B, the middle leg portions 13A, B and the left and right leg portions 11A, B, 12A, B The outer surfaces 14A, B, C, and D that connect them are cut into a C-plane shape. The corresponding outer side surfaces 41A, B, C, and D of the bobbins 40A and B that cover the partial cores 10A and B (hereinafter, the two partial cores 10A and B are also collectively referred to as a core portion 10) Is formed.

In this manner, the assembly of the core portion 10, the coil portion 20, and the bobbins 40A and B can be integrally screwed to the case 50. In practice, the members are bonded to each other with an adhesive in a positioned state. Further, as will be described later, the relative position between the members is fixed by filling the insulating adhesive between the members.
The case 50 is provided with a space 70 at the top in the state where the bobbins 40A and B are assembled. The space 70 is filled with a fluid insulating resin agent 71 and includes the entire coil portion 20. And overmolded. Thereby, the insulating resin agent 71 functions as a protective layer, and it is possible to prevent a situation where each member is damaged when it comes into contact with a member outside the reactor.
The core portion 10 is made of a powder magnetic core obtained by forming a ferromagnetic material such as iron powder into a fine powder, covering the surface with an insulating coating, and compressing and hardening. Examples of the ferromagnetic material include pure iron or iron containing one or more additive elements selected from Ni, Cu, Cr, Mo, Mn, C, Si, Al, P, B, N, and Co. An alloy is given as an example.

Moreover, although the said coil part 20 is formed by winding a rectangular wire, it may replace with a rectangular wire and may be formed with a round wire. A flat wire is a belt-like flat conductor as shown in FIG. 1 and the like, and for example, a wire having a thickness of 0.5 to 6.0 mm, a width of 1.0 to 16.0 mm and the like is generally used. For example, a round wire having a diameter of about 0.03 mm to about 3.0 mm can be suitably used.
As shown in FIG. 3 (A), the bobbins 40A and B have a shape in which the core portion 10 is made one size larger so as to cover the core portion 10, and formability, mass productivity, fine workability, electrical insulation are formed. For example, it is molded using insulating resins such as thermoplastic resins such as PPS and 6,6-nylon, and thermosetting resins such as phenol and unsaturated polyester. The

The case 50 is made of aluminum, but other various materials can be used.
The outer corners of the case 50 are provided with mounting portions 53A, B, C, and D for attaching the reactor 1 to the predetermined portions of the case 50 for each case 50. The portions 53A, B, C, and D are provided with through holes 51A, B, C, and D for screwing.
Further, one opposing surface 52B, D of the case 50 is flush with each other, but the other opposing surface 52A, C is a protruding portion 42A, B, C of the bobbin 40A, B at each corner. It is formed so as to be bent outward in the vicinity of each corner so as to accommodate the protruding shape of D.

By the way, the center legs 13A and 13B of the core portion 10 are formed by abutting the center legs 13A and 13B of the E-shaped partial cores 10A and B through a spacer 16 for magnetic saturation. Further, the basic shape of the central legs 13A and 13B is a prismatic shape.
However, since the ridge line portion of the corner portion protrudes outward and easily comes into contact with the inner peripheral portion 21 of the coil portion 20, the coil portion 20 is increased in diameter for safety. Moreover, it is uneconomical in terms of materials. Furthermore, there is a demand for higher withstand voltage between the core and the coil when the current of the battery is increased, and measures such as securing the distance and securing the withstand voltage with an insulator have become necessary. Diameter.
Therefore, in the present embodiment, as shown in FIGS. 1 and 2, the step portions 23A1, A2, 23B1, and B2 are formed so that the shape of the ridge line portion of the core portion 10 that easily contacts the inner peripheral portion 21 of the coil portion 20 is shown. I am trying to provide it.

  Thereby, the ridge line part (corner part) of the core part 10 will be in the state dented with respect to the inner peripheral part 21 of the coil part 20, and the ridge line part (corner part) of the core part 10 and the inner peripheral part 21 of the coil part 20 Since a space margin is created during this period, the diameter of the coil portion 20 can be reduced. Thereby, the reactor 1 can be made compact. In addition, the efficiency of the material for forming the core portion 10 and the coil portion 20 can be increased.

  In addition, the shape of the ridge line portion is a step portion constituted only by a flat surface, and molding can be performed regardless of the pressing direction, so that the pressing direction (the granular structure is flattened by compression). Even if the direction is set to a direction orthogonal to the magnetic path plane, it can be formed well by press molding. Accordingly, it is possible to perform press molding so that the direction in which the magnetic flux flows and the major axis direction of the magnetic substance particle shape coincide with each other, so that the initial L value (inductance) and the BH characteristics particularly in the low to medium magnetic flux region. Etc. can be improved.

Moreover, in the reactor 1 of this embodiment, although the front-end | tip of corresponding leg part 11A, B, 12A, B, 13A, B of each E-shaped partial core 10A and B is mutually abutted and combined, The part has a curved surface as a whole. That is, as is apparent from FIGS. 1 and 2, both end portions in the left-right direction (leg portion arranging direction) of each leg portion 11A, B, 12A, B, 13A, B are cylindrical side surfaces having axes in the vertical direction. The shape approximates the shape.
By making the tips of the leg portions 11A, B, 12A, B, 13A, and B that face each other have such a curved surface shape, the DC superposition characteristics can be improved.

Further, as described above, in this embodiment, the case 50 is filled with the insulating resin agent 71 made of silicon, urethane, epoxy, or the like. In the initial state, such a resin has fluidity, so that it can enter the gap between the core portion 10 and the coil portion 20 to improve the insulation between them. Further, by using such an insulating resin agent 71, the insulation can be ensured even if the gap between the two is small, so that the clearance can be reduced and the compactness can be achieved. Can be promoted.
Moreover, in this embodiment, when manufacturing the reactor 1, the method of insert molding is used.

That is, after the core portion 10 is molded, the core portion 10 and the coil portion 20 are set in an insert molding machine in a state of being housed in the case 50 as shown in FIG. After the agent 71 is filled in the case 50, an integral molding process is performed in the mold.
Thereby, the whole reactor 1 can be integrated rapidly and reliably, ensuring insulation.

In the above embodiment, the E-shaped partial cores 10A and 10B are combined to form a so-called “day-shaped” core portion 10, and the coil portion 20 is wound around the central legs 13A and 13B. The shape of the core part 10 and the position where the coil part 20 is wound are not limited to this.
For example, as shown in FIG. 4A and FIG. 4B which is a partial cross-sectional view thereof, coil portions 120A and B are wound around the left and right leg portions 112A and B of the rectangular core portion 110, respectively. In this case, the present invention may be applied (modified shape 1).

That is, the substantially U-shaped partial cores 110A and B (both are also referred to as the core portion 110) are formed so that the left and right leg portions 111 and 112 are brought into contact with each other to become a substantially square core portion, Coil portions 120A and 120B are arranged so as to wind around the butted portions of the left and right leg portions 111 and 112, respectively. The ridge line portions of the left and right leg portions 111 and 112 that are likely to be close to the inner peripheral portions 121A and B of the respective coil portions 120A and B have two ridge line portions so as to be away from the inner peripheral portions 121A and B. Step portions 123A1 to 123A1 and 123B1 to 4 cut into a step shape on a plane are formed.
This increases the minimum distance between the inner peripheral portions 121A and B of the coil portions 120A and B and the ridge line portions of the core portion 110, and even if the coil portions 120A and B are further reduced in diameter, there is a possibility of contact with the core portion 110. Can be reduced.

  Further, for example, as shown in FIG. 5A and FIG. 5B, which is a partial cross-sectional view thereof, coil portions 220A and B are respectively attached to the left and right leg portions 211B and 212B of the core portion of the UI combination shape. You may apply this invention, when winding (change shape 2).

That is, the substantially U-shaped partial core 210A and the substantially I-shaped partial core 210B (both are also referred to as the core portion 210), the left and right leg portions 211 and 212, and the tip surface thereof is a substantially I-shaped portion. Coil portions 220A and B are respectively formed so that a core portion is formed in contact with the front side surface (back side in the depth direction of the paper surface) of the core 210B and wound around predetermined portions of the left and right leg portions 211 and 212. Is arranged. The ridge line portions of the left and right leg portions 211 and 212 that are likely to be close to the inner peripheral portions 221A and B of the respective coil portions 220A and B have two ridge line portions so as to be away from the inner peripheral portions 221A and B. Step portions 223A1 to 223B1 and 223B1 to 4 cut into a step shape on a plane are formed.
As a result, the minimum distance between the inner peripheral portions 221A and 221B of the coil portion 220 and the ridge line portion of the core portion 210 is increased, and the possibility of contact with the core portion 210 is reduced even if the coil portions 220A and B are further reduced in diameter. be able to.

For example, as shown in FIG. 6 (A) and FIG. 6 (B) which is a partial cross-sectional view thereof, the left and right leg portions 311A, B, 312A, and B of the UU combination-shaped core portion 310 are each coiled. You may apply this invention, when winding part 320A, B (change shape 3).
That is, the substantially U-shaped partial cores 310A and B (both are also referred to as the core portion 310), the left and right leg portions 311A, B, 312A, and B, and the front end surfaces thereof are butted against each other. The coil portions 320A and 320B are arranged so as to be wound around the butted portions of the left and right leg portions 311A, B, 312A, and B, respectively. The ridgeline portions of the left and right leg portions 311A, B, 312A, and B that are likely to be close to the inner circumferential portions 321A and B of the coil portions 320A and B are ridgelines so as to be away from the inner circumferential portions 321A and B. Step portions 323A1 to 323B3 to 323B1 to 4 are formed by cutting the portion into steps in two planes.
As a result, the minimum distance between the inner peripheral portions 321A and B of the coil portion 320 and the ridge line portion of the core portion 310 is increased, and the possibility of contact with the core portion 110 is reduced even if the coil portions 320A and B are further reduced in diameter. Can do.

In the modified shape 3 described above, the ridgeline of the core portion 310 is continued not only to the portions adjacent to the inner peripheral portions 321A and B of the coil portions 320A and B but also to the step portions 323A1 to 4 and 323B1 to 4. Step portions 323C and D are also formed in other regions of the portion. Thus, by forming the step portions 323A1-4, 323B1-4, 323C, D over the entire circumference, the manufacturability at the time of molding can be improved.
(Modification)

The coil component of the present invention is not limited to the above-described embodiment and the modified shape, and various other modifications can be made.
For example, the shape of the coil bobbin and the case is not limited to those of the above embodiment and the above modified shape, but can be changed to various other shapes and types. For example, in the reactor of the above-described embodiment, each ridge line portion of the central leg is provided, and in the above modification, each ridge line portion of the left and right leg portions is provided with a single stepped portion. Any shape that can increase the minimum distance from the inner peripheral surface of the coil portion as long as the shape of the ridge line portion of the prism is cut off by a plane and roughly along the inner peripheral surface of the coil portion may be used.
Therefore, it is possible to form a C-plane shape in which each ridge line portion is cut off by one plane, and it is possible to form the step portion shown in the embodiment in two or more steps.

In the above embodiment, the spacer 16 made of a non-magnetic material is disposed between the tips of the central legs 13A, B. However, three central legs 13A, B, which are magnetic materials, are provided in the axial direction. The above magnetic material parts may be divided and a spacer made of a non-magnetic material may be disposed between the magnetic material parts.
Moreover, in the said embodiment and the said modification, although the core part is formed combining 2 partial cores, you may form a core part combining 3 or more partial cores.
Hereinafter, the reactor according to the embodiment of the present invention will be described in comparison with a comparative example.

  As an example shown in FIG. 7A, an example core part 410 (partial cores 410A, B) is formed by forming in the same shape as the core part 10 of the embodiment shown in FIG. In combination). At the same time, as a comparative example, a comparative example core part is produced by forming in the same shape as the core part 410 of this example and performing molding press in a direction (front-rear direction) perpendicular to the pressing direction of the example did.

Moreover, the coil part of an Example and a comparative example was produced by the shape and winding specification similar to the coil part 20 of embodiment shown in FIG.
A BH curve and a DC superimposition characteristic curve were obtained by simulation for the example sample and the comparative example sample thus manufactured.

  As shown in FIG. 7B, it is clear that the magnetic permeability (B / H) obtained in the example (solid line) is higher than that in the comparative example (broken line).

Also, as shown in FIG. 8, it is clear that the initial L value (μH) is higher in the example (solid line) than in the comparative example (broken line).
That is, as shown in Table 1 below, in the comparative example, the initial L value is 133 μH, whereas in the example, the initial L value is 146 μH. The initial L value can be increased by about 9.8%.

1 Reactor 10, 110, 210, 310, 410 Core part 10A, B, 110A, B, 210A, B, 310A, B, 410A, B Partial core 11A, B, 12A, B, 111, 112, 211, 212, 311A, B, 312A, B Left and right leg portions 13A, B Central leg portions 14A to D Outer side surfaces 20, 120A, B, 220A, B, 320A, B Coil portions 21, 121A, B, 221A, B, 321A, B Peripheral part 23A1, A2, 23B1, B2, 123A1-A4, 123B1-B4, 223A1-A4, 223B1-B4, 323A1-A4, 323B1-B4, 323C, D Step part 30 Heat transfer sheet 41A-D Corresponding outer surface 42A ~ D Overhang 50 Case 51A ~ D Through-hole 52A ~ D Opposing surface 53A ~ D Mounting part 54A, B Step 60 A to D Screw 70 Space portion 71 Insulating resin agent

Claims (6)

A coil section;
A core portion that is formed into a predetermined magnetic path shape using a dust core, and the coil portion is inserted around a part of the magnetic path shape,
In the portion of the core portion around which the coil portion is wound, the ridge line portion facing the inner peripheral portion of the coil portion is cut into a shape that is cut off with a flat surface along the inner peripheral portion. Reactor to do.   The reactor according to claim 1, wherein a particle shape of the dust core constituting the core portion is a shape compressed in a direction orthogonal to a magnetic path plane.   The reactor according to claim 1 or 2, wherein a corner portion of the ridge line facing the inner peripheral portion of the coil portion is cut into a stepped shape.   The reactor according to any one of claims 1 to 3, wherein the stepped portion has four stepped portions facing each other in the radial direction of the coil portion.   2. The core portion is configured such that legs of two E-shaped partial cores abut each other, and the coil portion is inserted through a middle leg portion of the E-shaped partial core. The reactor of any one of -4. A core part is formed by combining partial cores formed by compressing a dust core in a direction perpendicular to the magnetic path plane,
Around the part of this core part, arrange the coil part that passes through this core part,
When forming the partial core, the ridge line portion of the partial core facing the inner peripheral portion of the coil portion has a shape cut off with a flat surface along the inner peripheral portion. Production method.

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