JP2008021948A - Core for reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core for a reactor which is excellent in heat radiation. <P>SOLUTION: The core 2 consists of an inner core 21, an outer core 22, end cores 23A, 23B, and a gap 4 is attached on the core 2. The gap 4 is formed by distributing and disposing a plurality of gap materials 41-44 in the inner core 21, and the inner core 21 is divided into a plurality of core pieces 21A-21E by the gap materials. The gap materials 41-44 are each a gap material having a high thermal conductivity gap material made of a material having a thermal conductivity of not less than 100 W/m×K and a specific resistance of not less than 1.0×10<SP>7</SP>Ωm at 25°C. The heat of the core pieces 21B-21D is efficiently transmitted to core pieces adjacent thereto through the gap materials 41-44, thereby ensuring heat radiation performance of the core pieces 21B-21D and improving the heat radiation performance of the core 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reactor core. In particular, the present invention relates to a reactor core having excellent heat dissipation.

  The reactor includes a core and a coil, and can store electric energy as magnetic energy. For example, the reactor is used as one of components of a booster circuit included in a hybrid vehicle or an electric vehicle.

  The shape of a typical reactor core used in a booster circuit of a hybrid vehicle or the like is a ring-shaped core as shown in Patent Document 1, and is configured by combining a plurality of core members. Specifically, this core is composed of a pair of U-shaped cores having rectangular end faces and four I-shaped cores, and each U-shaped core is arranged such that the end faces face each other. Two I-shaped cores are arranged in between. Further, a gap is formed between adjacent core members, and a gap material is used for the gap (see FIG. 1 of the same document). A coil having a winding wound around a part of such a core is mounted, and a current flows through the coil to form a closed magnetic circuit in the core. The material constituting the core is a ferromagnetic material, and for example, an iron-based material such as silicon steel is used.

  For example, Patent Document 2 shows a core used for a choke coil, and this core is composed of an upper core and a lower core made of ferrite. The upper core and the lower core have substantially symmetrical shapes, and each has an E shape when viewed from the end surface. Specifically, the upper core has a rectangular ceiling portion, a columnar core portion extending downward from the center portion thereof, and a pair of side wall portions extending from both sides of the ceiling portion. The core has a rectangular bottom, a columnar core extending upward from the center thereof, and a pair of side walls extending from both sides of the bottom. In the core, the upper core and the lower core are combined so that the cylindrical core portions face each other through a space gap, and the side wall portions contact each other to form a closed magnetic circuit (see FIG. 2 of the same document).

  In the cores described above, a gap is provided in the core (magnetic path) in order to adjust the magnetic permeability of the core and to set the inductance of the reactor to a desired value. The gap is formed of a non-magnetic material, and an air gap is used as the gap material in addition to a plate material made of glass epoxy or alumina.

  Here, in a high-power reactor provided in a hybrid vehicle or the like, the copper loss due to the winding resistance when the coil (winding) is energized and the iron loss of the core that forms the magnetic path are large, depending on the usage situation. It may be as high as above. In addition, since a large current is supplied to the coil in such a reactor, it is necessary to increase the gap distance in order to suppress a decrease in inductance due to magnetic saturation. However, when a gap is provided only at one location in the core, the leakage flux at the gap location increases, and eddy current loss due to the leakage flux increases in the winding. Therefore, it is necessary to disperse a plurality of gaps in the core while maintaining the entire gap distance as shown in FIG.

JP 2004-241475 A JP 2005-45119 A

  However, the glass epoxy, alumina, and air that make up the gap have low thermal conductivity, and even in the alumina with relatively high thermal conductivity, the thermal conductivity at 25 ° C is 17 W / m · K. . Therefore, when a gap is provided in the core, the heat dissipation of the core member in contact with the gap is impaired, and there is a problem of overheating due to heat conducted from the coil and iron loss. In particular, a core member that is formed with a gap at both ends and is entirely covered with a coil has a structure that is difficult to be cooled, and it has been difficult to ensure sufficient heat dissipation.

  When the core member sandwiched between the gaps is not sufficiently dissipated and the temperature exceeds the limit and the temperature becomes high, the following problems may occur and the stability and safety of the reactor may be impaired.

  (1) The inductance of the reactor changes as the magnetic permeability of the core itself changes.

  (2) The insulating material coated on the winding is deteriorated by heat, and the winding is short-circuited.

  This invention is made | formed in view of the said situation, The objective is to provide the core for reactors which is excellent in heat dissipation.

  The reactor core according to the present invention includes an inner core disposed inside the coil, an outer core disposed outside the coil, and end cores disposed on both ends of the coil. The inner core is composed of a gap material and a core piece, and at least one of the gap materials is composed of a high thermal conductivity material having a thermal conductivity at 25 ° C. of 100 W / m · K or more. . Hereinafter, a gap made of a high thermal conductivity material is referred to as a high thermal conductivity gap material.

  According to this configuration, the heat of one core piece in contact with the high thermal conductivity gap material can be easily transmitted to the other core piece, and the heat dissipation of the core piece can be improved. There is at least one gap, and when there are a plurality of gaps, a part of the gaps may be a high thermal conductivity gap material. Here, if all the gaps are high thermal conductivity gap materials, the heat dissipation of each core piece of the inner core divided by the gap can be improved, and the reactor core can be radiated more effectively. .

  At least one of the gap materials provided at both ends of the core piece is preferably a high thermal conductivity gap material.

  According to this structure, the heat dissipation of the core piece sandwiched between the gaps can be improved. Here, if the gap located at both ends of the core piece is a high thermal conductivity gap material, the heat dissipation of the core piece sandwiched between the gaps can be further enhanced.

  Another reactor core according to the present invention includes an inner core disposed inside the coil, an outer core disposed outside the coil, and end cores disposed on both ends of the coil. The inner core is composed of a gap material and a core piece. The core pieces adjacent to each other through the gap are thermally connected by a heat dissipating member disposed on the outer peripheral surface of the inner core, and the heat dissipating member has a thermal conductivity at 25 ° C. of 100 W / m · It is characterized by being made of a high thermal conductive material of K or higher.

  According to this configuration, the heat of one core piece in contact with the heat dissipation member can be easily transmitted to the other core piece, and the heat dissipation of the core piece can be improved. Here, if the heat dissipation member is arranged on the outer peripheral surface of the inner core so that all the core pieces are thermally connected, the heat dissipation of each core piece of the inner core divided by the gap can be improved, Heat dissipation of the reactor core can be performed more effectively.

  Moreover, the said heat radiating member may be formed in a cylinder shape and the whole outer peripheral surface of the said inner core may be covered with a heat radiating member.

  By making the heat radiating member cylindrical, the contact area between the core piece and the heat radiating member can be increased, and the heat of the core piece can be efficiently transmitted. Moreover, since the whole outer peripheral surface of a core piece is covered with a heat radiating member, the heat distribution of a core piece can be made uniform from the center part to the outer peripheral side. Furthermore, the heat radiating member formed in the cylindrical shape can be used as a bobbin of the coil. Flange portions extending radially outward may be provided at both ends of the heat radiating member formed in a cylindrical shape, and heat is applied to the end core from the heat radiating member by contacting the flange portion and the end core. It can be made easier to communicate.

  In the reactor core in which the heat dissipating member is disposed on the outer peripheral surface of the inner core, at least one of the gap members provided in the inner core is preferably a high thermal conductivity gap material.

  The heat of the core piece can be transmitted to the adjacent core piece through the heat radiating member, and can be transmitted to the adjacent core piece through the high thermal conductivity gap material, so that the heat dissipation of the core piece can be further improved.

The high thermal conductivity material forming the high thermal conductivity gap material and the heat radiating member preferably has a specific resistance of 1.0 × 10 ⁷ Ωm or more.

  By using such an insulating material, it is possible to reduce the eddy current loss caused by the magnetic flux and suppress the heat generation of the high thermal conductivity gap material and the heat radiating member itself. By suppressing the heat generated by these members themselves, the heat dissipation of the reactor core can be improved without inhibiting the heat dissipation of the core piece. Moreover, when using the heat dissipation member also as a bobbin of the coil, it is possible to sufficiently ensure the insulation between the coil and the inner core, and further by providing a flange portion extending radially outward from both ends of the cylindrical shape, The insulation between the coil and the end core can also be secured.

  Hereinafter, the reactor core of the present invention will be described in detail.

  The core for reactors of this invention can utilize the core of various shapes, such as a pot core, EI core, and EE core. As a member constituting the core having such a shape, a laminated body of electromagnetic steel sheets or a compacted body obtained by filling a magnetic mold with a magnetic powder and pressing it can be used. In particular, use of a green compact is preferable because a complex three-dimensional core such as a pot core can be easily and accurately produced.

  The assembly of the core having such a shape can be performed by individually manufacturing the inner core, the one end core, the outer core, and the other end core, and then joining these core constituent members. Further, a plurality of these core constituent members may be integrally formed in advance by compacting or the like. If a plurality of core components are integrally formed in this way, the number of parts is reduced and the number of joints can be reduced, resulting in excellent productivity. Adhesives and bolts can be used for joining the core constituent members. For example, urethane resin or epoxy resin adhesives can be used as the adhesive.

  In particular, the shape of the reactor core is preferably a pot core. The pot core usually has a cylindrical outer core and a pair of end cores joined to both ends of the outer core, and can substantially cover the coil. As described above, since the core constituent member is also located on the outer periphery of the coil, the pot core can have a large contact area between the core and the coil, and can easily transfer the heat from the coil to the core. Excellent.

  In the case of a pot core, since the coil is housed in the core, noise due to vibration accompanying excitation of the coil can be effectively suppressed, and the coil can be mechanically protected.

  In addition, since the pot core has a structure that easily releases heat from the outer core and each end core, for example, by fixing the core so as to contact a case made of aluminum with high thermal conductivity, the core of the reactor core The heat dissipation can be further improved.

  When the core shape is a pot type, a rod-shaped body is typically used as the inner core. The cross-sectional shape of the inner core may be a polygon as well as a circle. The outer core can cover the coil, and a cylindrical body is typically used. The cross-sectional contour shape of the outer core may be polygonal as well as circular, but an outer core having a cross-sectional contour shape corresponding to the cross-sectional shape of the inner core is usually used. On the other hand, the end cores are a pair of core constituent members located at both ends of the outer core, and are usually plate-like bodies having a shape corresponding to the cross-sectional contour shape of the outer core. For example, when the shape of the reactor is a prismatic shape, it is conceivable that the inner core is formed in a rectangular bar shape, the outer core is formed in a rectangular tube shape, and each end core is formed in a polygonal flat plate shape.

  The gap is provided in the inner core, and the inner core is composed of a gap material and a core piece. The gap may be provided near the end core, that is, at the end of the inner core. In this case, if the gap is a high thermal conductivity gap material, the heat of the core piece is transferred to the end core through the gap material. Can do. Moreover, if a heat radiating member is arrange | positioned on the outer peripheral surface of an inner core so that a core piece and an edge part core may be thermally connected, the heat | fever of a core piece can be transmitted to an edge part core through a heat radiating member.

  In the case of providing a plurality of gaps, the distance between the gaps and the number of gaps to be provided may be appropriately determined so as to obtain desired reactor characteristics.

  Here, one of the plurality of gaps may be an air gap. By providing the air gap, variations in the processing accuracy of the gap material such as the high thermal conductivity gap material can be absorbed by the air gap, and the gap distance can be easily adjusted. For example, even if the thickness of the gap material is thicker (thinner) than the prescribed thickness, the gap distance as a whole can be maintained by narrowing (widening) the air gap. Of course, even if an air gap is provided at one end of the core piece, heat dissipation is ensured by arranging a high thermal conductivity gap material at the other end of the core piece or arranging a heat dissipation member on the outer peripheral surface of the core piece. It is possible.

  According to the reactor core of the present invention, since the gap is made of a high thermal conductivity gap material, the heat of the core piece can be transmitted to the adjacent core piece or the end core through the high thermal conductivity gap material. It can be performed.

  According to another reactor core of the present invention, by disposing a heat radiating member on the outer peripheral surface of the inner core having a gap, the heat of the core piece can be transmitted to the adjacent core piece or the end core through the heat radiating member. Efficient heat dissipation can be performed.

  Embodiments of the present invention will be described below with reference to the drawings. Here, a pot type reactor core will be described as an example. In the drawings, the same symbols indicate the same items.

(Example 1)
<Overall structure of the reactor>
FIG. 1 shows a reactor 1 including a reactor core 2 and a coil 3 according to the present invention, and FIG. 2 shows a cross section of the reactor 1 passing through the central axis of the coil 3. The core 2 has a substantially cylindrical shape, and a coil 3 is accommodated in the core 2. The core 2 includes an inner core 21, an outer core 22, and end cores 23A and 23B. The core 2 is provided with a gap 4. Specifically, the gap 4 is formed by dispersing and arranging a plurality of gap members 41 to 44 on the inner core 21, and the inner core 21 is divided into a plurality of core pieces 21A to 21E by these gap members.

<Core>
The inner core 21, the outer core 22, and the end cores 23A and 23B constituting the core 2 are all formed of a powder compact.

  First, the inner core 21 is a round bar-shaped core disposed inside the coil 3. The inner core 21 includes disk-shaped core pieces 21A to 21E and disk-shaped gap members 41 to 44. More specifically, the inner core 21 is a round bar-like laminate obtained by alternately laminating and joining the core pieces 21A to 21E and the gap members 41 to 44. Here, the core pieces 21A and 21E are positioned at both ends of the inner core 21, but a configuration may be adopted in which the gap material is positioned at one or both of the ends.

  The joining of the core pieces 21A to 21E and the gap members 41 to 44 is performed by, for example, an adhesive. As the adhesive, for example, a urethane resin-based or epoxy resin-based adhesive can be suitably used. It is preferable to apply the adhesive as thinly as possible so that the thermal resistance at the joint surface between the core pieces 21A to 21E and the gap members 41 to 44 is reduced. Moreover, you may use the adhesive agent which mixed fillers, such as AlN, in the urethane resin type | system | group or the epoxy resin type adhesive, and improved the thermal conductivity.

  Next, the outer core 22 is a cylindrical core disposed outside the coil 3. Here, notches penetrating the inner and outer circumferences are provided in the opening portions at both ends of the outer core 22, and the terminal portions 31 and 32 of the coil 3 are drawn out from the notches. This notch may be an insertion hole, or a slit continuous from one end side to the other end side of the outer core 22.

  The end cores 23A and 23B are a pair of disk-shaped cores that are arranged on both ends of the coil and are respectively joined to the upper and lower ends of the outer core. Also, the upper end core 23A is joined to the upper end surface (core piece 21A) of the inner core 21, and the lower end core 23B is joined to the lower end surface (core piece 21E) of the inner core 21.

<Coil>
The coil 3 is typically formed by a winding having an insulating coating, and a spiral winding of a circular wire having a circular cross section or a so-called edgewise winding of a rectangular wire having a rectangular cross section can be used. The coil 3 is formed by winding a winding around the bobbin 5 in advance, and when assembling the core 2, the coil 3 integrated with the bobbin 5 may be disposed on the outer periphery of the inner core 21. The bobbin 5 is formed from an insulating material in order to ensure insulation between the coil 3 and the inner core 21. The bobbin 5 is preferably formed thin so that the heat of the coil 3 can be easily transferred to the core 2, and an appropriate thickness is selected so that sufficient insulation can be secured. The shape of the bobbin 5 has a cylindrical portion that fits the outer periphery of the inner core 21, and flange portions that protrude from both ends of the cylindrical portion, and the coil 3 is between one and the other of the flange portions. Will be formed.

<Gap material>
The gap 4 is formed by distributing gap materials 41 to 44 on the inner core 21. The gap members 41 to 44 are used to maintain a predetermined gap distance and to dissipate the core pieces 21B to 21D when the coil 1 is energized and the reactor 1 is driven. Specifically, the heat dissipation of the core pieces 21B to 21D is performed by transferring heat to the core pieces adjacent to each other via the gap members 41 to 44, and finally transferring heat to the end core 23A or 23B. .

The gap materials 41 to 44 are high thermal conductivity gap materials made of a material having a thermal conductivity at 25 ° C. of 100 W / m · K or more. When the thermal conductivity is 100 W / m · K or more, the heat of the core piece can be efficiently transferred to the adjacent core piece. The gap members 41 to 44 are made of a material having a specific resistance of 1.0 × 10 ⁷ Ωm or more, and can reduce eddy current loss caused by magnetic flux and suppress heat generation of the gap member itself. Specific examples of materials having such characteristics include ceramics such as aluminum nitride (AlN), beryllium oxide (BeO), and silicon carbide (SiC), diamond, and the like. Specifically, the thermal conductivity and specific resistance of each of the above materials are about 140 to 250 W / m · K and about 1.0 × 10 ¹¹ Ωm for AlN, about 250 W / m · K and 1.0 × 10 ¹³ Ωm for BeO, and about 210 W for SiC. / m · K and about 1.0 × 10 ¹¹ Ωm, diamond is about 1000 to 2000 W / m · K and about 5.0 × 10 ⁷ Ωm. The gap material is preferably formed from a non-magnetic material.

  The shape of the gap members 41 to 44 is preferably the same shape as the end surfaces of the core pieces to be joined so that the contact areas with the core pieces 21A to 21E are increased. By setting it as the gap materials 41-44 of such a shape, the heat of a core piece can be efficiently transmitted to an adjacent core piece through a gap material.

  The thickness of the gap members 41 to 44 is preferably set to a thickness that matches the gap distance determined so that desired reactor characteristics can be obtained. If there is a clearance between the core pieces 21A to 21E and the gap members 41 to 44, it is not preferable in that the heat conduction from the core pieces to the gap member is hindered. The thickness of the gap members 41 to 44 is preferably 2.0 mm or less in order to reduce leakage magnetic flux and reduce eddy current loss generated in the winding.

<How to assemble>
Reactor 1 is assembled as shown in FIG.

  The inner core 21 is manufactured by alternately stacking and integrating the core pieces 21A to 21E and the gap members 41 to 43 in advance. Here, the core piece 21A is located at the upper end of the inner core, and the core piece 21E is located at the lower end.

  Next, the lower end surface of the inner core 21 is joined to the lower end core 23B. This bonding may be performed using the above-described adhesive or the like.

  Next, the coil 3 is fitted into the inner periphery of the outer core 22, and the terminal portions 31 and 32 of the coil 3 are pulled out from the notch to the outer periphery of the outer core 22.

  Subsequently, the lower end surface of the outer core 22 is joined to the lower end core 23B. This bonding may be performed using the above-described adhesive or the like. By this joining, the inner core 21, the coil 3, and the outer core 22 are held substantially concentrically.

  Finally, the upper end core 23A is joined to the upper end surface of the outer core 22. This bonding may be performed using the above-described adhesive or the like. At this time, the upper end core 23A is also joined to the upper end surface of the inner core 21.

<Effect>
According to the reactor core of the first embodiment described above, the high thermal conductivity gap material is disposed between the core pieces of the inner core divided by the gap, so that the heat of the core piece is adjacent to the core piece through the gap material. It can be efficiently transmitted to the piece, and the heat dissipation of the core piece can be ensured. Here, a specific heat flow will be described by taking the core piece 21C as an example. First, the heat of the core piece 21C is transferred to the core piece 21B (21D) through the gap member 42 (43), and then transferred to the core piece 21A (21E) through the gap member 41 (44). Further, the heat transferred to the core piece 21A (21E) is transferred to the end core 23A (23B) joined to the end face and radiated to the outside.

  In Example 1 described above, the inner core, one end core, the outer core, and the other end core were individually formed and then joined together to assemble the core. It may be formed in advance by compaction or the like. Various shapes of the core constituent member obtained by integrally molding a plurality of these core constituent members can be considered, but an example thereof will be described here. Hereinafter, a modified example will be described based on FIG. 4 with a focus on differences from the reactor core of FIG.

(Modification 1)
The upper core 2A is a core component member formed by integrally forming the upper end portion (core piece 21A) of the inner core 21, the upper portion of the outer core 22, and the upper end core 23A. The lower core 2B is the inner core 21. This is a core structural member in which a lower end portion (core piece 21E), a lower portion of the outer core 22, and a lower end core 23B are integrally formed. The remaining portion of the inner core 21 is a laminated body in which the gap members 41 to 43 and the core pieces 21B to 21D are alternately laminated and integrated. In this laminate, the gap material 41 is located at the upper end and the gap material 44 is located at the lower end.

  In the case of the core 2 including the core component having such a shape, the reactor 1 is assembled as follows, for example.

  First, the lower end surface (gap material 44) of the laminate prepared in advance is bonded onto the core piece 21E integrally formed with the lower core 2B.

  Next, the coil 3 is fitted into a space formed between the outer periphery of the laminate and the inner periphery of the outer core lower part 22B formed integrally with the lower core 2B.

  Finally, the outer core upper part 22A integrally formed with the upper core 2A and the outer core lower part 22B integrally formed with the lower core 2B are abutted and joined. At this time, the core piece 21A integrally formed with the upper core 2A and the upper end surface (gap material 41) of the laminate are joined.

  By integrally molding a plurality of core constituent members in this way, the number of parts can be reduced and the number of joints can be reduced, so that the productivity of the reactor is improved.

(Example 2)
Next, with reference to FIG. 5, the Example which has arrange | positioned the thermal radiation member 6 to the outer peripheral surface of the inner core 21 is demonstrated. The second embodiment is different from the first embodiment in that a heat radiating member is provided, and other configurations are the same as the first embodiment. Here, the shape of the inner core 21 is a square bar having a square cross section.

<Heat dissipation member>
The heat dissipating member 61 is disposed on one side of the inner core 21 inside the coil 3 and is used to dissipate the core pieces 21B to 21D when the coil 1 is energized and the reactor 1 is driven. Specifically, the heat dissipation of the core pieces 21B to 21D is performed by transferring heat to the adjacent core pieces via the heat dissipation member 61 and finally transferring the heat to the end core 23A or 23B.

The heat dissipating member 61 is made of a material having a thermal conductivity at 25 ° C. of 100 W / m · K or more and a specific resistance of 1.0 × 10 ⁷ Ωm or more. When the thermal conductivity is 100 W / m · K or more, the heat of the core piece can be efficiently transferred to the adjacent core piece, and when the specific resistance is 1.0 × 10 ⁷ Ωm or more, the eddy current generated by the magnetic flux Loss can be reduced. Further, the heat radiating member 61 is preferably made of a nonmagnetic material.

  The shape of the heat radiating member 61 is a rectangular shape along the side surface (outer peripheral surface) of the inner core 21, and is a flat plate shape. If it is a flat heat dissipation member, processing is easy. The length and width of the heat radiating member 61 are preferably at least large enough to be in contact with both the core piece and the adjacent core piece, and the contact area between the core pieces 21A to 21E and the heat radiating member 61 should be increased. Is preferred. With the heat dissipation member having such a size, the heat of the core piece can be efficiently transmitted to the adjacent core piece through the heat dissipation member 61.

  In addition, the thickness of the heat radiating member 61 may be appropriately determined according to the strength of the heat radiating member.

  In this example, the integral heat dissipation member 61 is in contact with each of the core pieces 21A to 21E. For example, the first heat dissipation member in contact with the core pieces 21A and 21B, the second heat dissipation member in contact with the core pieces 21B and 21C, and the core A heat radiating member including a third heat radiating member in contact with the pieces 21C and 21D and a fourth heat radiating member in contact with the core pieces 21D and 21E may be used. These heat radiating members divided into a plurality may be arranged with a space, but by connecting so as not to divide the heat path, the heat of the core pieces 21B to 21D is passed through the heat radiating member to the core pieces 21A, 21E. Alternatively, it is preferable that it can conduct directly to the end cores 23A and 23B.

  The heat dissipating member 61 is disposed so as to contact one side surface of the inner core 21, and the heat dissipating member 61 and the inner core 21 are joined together by, for example, an adhesive. As the adhesive, for example, a urethane resin-based or epoxy resin-based adhesive can be suitably used. It is preferable to apply the adhesive as thinly as possible so that the thermal resistance at the joint surface between the core piece and the heat dissipation member 61 is reduced. Moreover, you may use the adhesive agent which mixed fillers, such as aluminum nitride (AlN), in urethane resin type | system | group and an epoxy resin type | system | group adhesive agent, and improved the thermal conductivity.

<Gap material>
In this example, the gap materials 41 to 44 may be a gap material made of a conventional material such as alumina, but are preferably a high thermal conductivity gap material. If a high thermal conductivity gap material is used, the heat of the core piece can be transmitted to the adjacent core piece via the heat dissipation member 61 and also via the high thermal conductivity gap material, further improving the heat dissipation of the core piece. Can be made.

<Effect>
According to the reactor core of Example 2 described above, by disposing the heat radiating member on the outer peripheral surface of the inner core, the heat of the core piece can be efficiently transmitted to the adjacent core piece through the heat radiating member. The heat dissipation of the piece can be ensured. Here, the specific heat flow will be described by taking the core piece 21C as an example. The heat of the core piece 21C is transferred to the core piece 21A (21E) through the heat radiating member 61, and the heat transferred to the core piece 21A (21E). Is transmitted to the end core 23A (23B) joined to the end face and radiated to the outside.

  In the second embodiment, the reactor core in which the flat heat dissipation member 61 is disposed on one side surface of the inner core 21 has been described. However, a plurality of the heat dissipation members 61 are prepared, and the heat dissipation member 61 is provided on the plurality of side surfaces of the inner core 21. May be arranged. If it does in this way, the contact area of core piece 21A-21E and a thermal radiation member can be increased, and the heat dissipation of a core piece can be improved more. Further, when the heat radiating member 61 is arranged only on one side surface of the inner core 21, the central axis of the inner core 21 and the central axis of the outer core 22 are shifted, so that the magnetic flux distribution is not uniform in the outer core. There is a fear. Therefore, when disposing the heat radiating member on the plurality of side surfaces of the inner core, it is preferable to dispose them on at least both side surfaces facing each other, and more preferably on all side surfaces.

(Modification 2)
FIG. 6 shows a modification in which a heat radiating member 62 formed in a cylindrical shape is arranged on the outer peripheral surface of the inner core 21. Here, the configuration of the core 2 is the same as that of the first modification, and the heat radiating member 62 is formed of the same material as the heat radiating member 61 described above.

  The heat dissipating member 62 is a cylindrical member that fits the outer periphery of the inner core 21, and may be composed of a plurality of divided pieces. Further, the heat dissipating member 62 is provided with flange portions 62A and 62B projecting from the cylindrical portion at both ends of the heat dissipating member 62, like the bobbin 5 in FIG.

The heat dissipating member 62 is formed of an insulating material having a specific resistance of 1.0 × 10 ⁷ Ωm or more, and even if the insulation coating of the windings constituting the coil 3 is deteriorated, the coil 3 and the inner core 21 Insulation can be secured sufficiently. Further, the flange portions 62A and 62B of the heat radiating member 62 are formed of the same material as the heat radiating member, so that the heat transferred from the core pieces 21B to 21D to the heat radiating member 62 is easily transferred to the end cores 23A and 23B. Yes.

  When assembling the reactor 1, the coil 3 is formed by winding the heat radiating member 62 in advance, and then the heat radiating member 62 together with the coil 3 may be disposed on the outer peripheral surface of the inner core 21.

  When such a heat radiating member 62 is arranged on the outer peripheral surface of the inner core 21, the entire outer peripheral surface of the inner core 21 is covered with the heat radiating member 62, and the contact area between the core pieces 21A to 21E and the heat radiating member 62 is large. , Can transfer heat efficiently. Moreover, the heat distribution of the core pieces 21A to 21E can be made uniform. Furthermore, the heat radiating member 62 can be used as a bobbin of the coil 3.

  In addition, the core for reactors of this invention can be suitably changed, without deviating from the summary of this invention, and is not limited to the said Example.

  The core for reactors of this invention can be utilized for the reactor by which high heat dissipation is requested | required. In particular, it can be suitably used for a reactor provided in a hybrid vehicle or an electric vehicle.

1 is a partially cutaway perspective view showing a schematic configuration of a reactor in Embodiment 1. FIG. 1 is a cross-sectional view of a reactor in Example 1. FIG. It is a disassembled perspective view of the reactor in Example 1. FIG. It is sectional drawing of the reactor in the modification 1. FIG. It is sectional drawing of the reactor in Example 2. FIG. It is sectional drawing of the reactor in the modification 2. FIG. It is a fragmentary figure of the core in which the gap was provided, (A) shows the case where a gap is provided only in one place, and (B) shows the case where a plurality of gaps are provided, respectively.

Explanation of symbols

1 Reactor
2 core 2A upper core 2B lower core
21 Inner core 21A-21E Core piece
22 Outer core 22A Upper outer core 22B Lower outer core
23A End core (upper) 23B End core (lower)
3 Coil 31,32 Coil end
4 Gap 41-44 Gap material (High thermal conductivity gap material)
5 bobbins
6 Heat dissipation member
61 Heat dissipation member (flat plate)
62 Heat dissipation member (cylindrical) 62A, 62B Flange
M1, M2 Core g Gap L Gap distance

Claims (6)

An inner core disposed on the inner side of the coil, an outer core disposed on the outer side of the coil, and end cores disposed on both ends of the coil;
The inner core is composed of a gap material and a core piece,
At least one of the gap members is made of a high thermal conductivity material having a thermal conductivity of 100 W / m · K or more at 25 ° C.   2. The reactor core according to claim 1, wherein at least one of the gap members formed at both ends of the core piece is made of the high thermal conductivity material. An inner core disposed on the inner side of the coil, an outer core disposed on the outer side of the coil, and end cores disposed on both ends of the coil;
The inner core is composed of a gap material and a core piece,
The core pieces that are adjacent to each other through the gap are thermally connected by a heat radiating member disposed on the outer peripheral surface of the inner core,
The core for a reactor, wherein the heat radiating member is made of a high heat conductive material having a thermal conductivity of 100 W / m · K or more at 25 ° C.   The reactor core according to claim 3, wherein the heat radiating member has a cylindrical shape and covers the entire outer peripheral surface of the inner core.   5. The reactor core according to claim 3, wherein at least one of the gap members is made of the high thermal conductivity material. The reactor core according to any one of claims 1 to 5, wherein the high thermal conductivity material has a specific resistance of 1.0 x 10 ⁷ Ωm or more.

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