JP6048652B2 - Reactor, converter, and power converter - Google Patents

Description

  The present invention relates to a reactor used for components of a power conversion device such as an in-vehicle DC-DC converter mounted on a vehicle that uses electric power for a drive source such as a hybrid vehicle or an electric vehicle, a converter using the reactor, The present invention also relates to a power converter using this converter.

  A reactor is one of the parts of a circuit that performs a voltage step-up operation or a voltage step-down operation. The reactor is used in a converter mounted on a vehicle such as a hybrid vehicle. As the reactor, for example, there is one shown in Patent Document 1.

  The reactor of patent document 1 is provided with the coil which has a pair of coil element, and the cyclic | annular magnetic core inserted in the inside of these coil elements. The magnetic core has a coil placement portion (inner core portion) disposed inside the coil element and an exposed portion (outer core portion) exposed from the coil element. And in patent document 1, it is set as the magnetic core which is hard to carry out magnetic saturation, ie, the reactor which is hard to carry out magnetic saturation, by making an outer core part into a high relative permeability rather than an inner core part.

JP 2009-33055 A

  In recent years, with the development of hybrid vehicles and the like, the current supplied to the reactor tends to increase. When the current supplied to the reactor is increased, even the reactor having the structure of Patent Document 1 may be magnetically saturated, and a countermeasure is desired.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a reactor that is less magnetically saturated than in the past. Another object of the present invention is to provide a converter using the reactor of the present invention and a power converter using the converter.

  In order to solve the above problems, the present inventor has studied a configuration in which a gap material is interposed between the inner core portion and the outer core portion. In addition, the present inventor also paid attention to the configuration for protecting the reactor from the external environment in the course of the study. As a result, the inventors have conceived a configuration that can achieve both the arrangement of the gap material and the protection of the reactor, thereby completing the present invention. Below, the reactor of this invention is prescribed | regulated.

  The reactor of the present invention includes a coil and a magnetic core having a portion inserted into the coil, and the magnetic core is disposed inside the coil, and the outer core portion is exposed from the coil. It is a reactor which has. In the reactor of the present invention, the inner core portion provided in the reactor is made of a magnetic powder mixed resin in which magnetic powder is dispersed in the resin, and the relative permeability of the outer core portion is larger than the relative permeability of the inner core portion. The outer core portion is used in the form of a core molded body to be described later.

  In addition, the reactor of this invention may be a reactor (refer Embodiment 1 mentioned later) provided with the coil which has a pair of coil element arranged in parallel, or a reactor (Embodiment) provided with the coil which has one coil element. 2). Further, the “inner core portion disposed inside the coil” in the reactor of the present invention means an inner core portion at least partially disposed inside the coil. For example, the case where the central portion of the inner core portion is located inside the coil and the vicinity of the end portion of the inner core portion is located outside the coil is also included in the “inner core portion disposed inside the coil”.

The core molding in the reactor of this invention has an outer core part and the core mold part which protects the outer core part. The core mold part covers at least the following two parts of the outer peripheral surface of the outer core part.
[1] A part facing outward from the reactor (in other words, a part that can be visually recognized from the appearance of the reactor when the core mold part is peeled off)
[2] The part facing the inner core part (even if the core mold part is peeled off, it cannot be visually recognized from the appearance of the reactor)

  Portions other than the above [1] and [2] on the outer peripheral surface of the outer core portion may be covered with the core mold portion or may not be covered. Specific examples of the portion that may or may not be covered with the core mold portion include the bottom surface of the outer core portion that faces the installation target of the reactor.

  According to the configuration of the present invention described above, the outer core portion of the outer peripheral surface of the outer core portion that faces outward from the reactor is covered with the core mold portion, so that the outer core portion can be protected from the external environment. Moreover, in the structure of this invention, the part which opposes an inner core part among the outer peripheral surfaces of the outer core part in a core molded object is also covered with the core mold part. Therefore, when a magnetic core is formed by combining the core molded body and the inner core portion, a part of the core mold portion is disposed between the outer core portion and the inner core portion and functions as a gap material for the magnetic core. The magnetic core can be made hard to be magnetically saturated. Thus, according to the structure of this invention, it can be set as the reactor which is hard to be magnetically saturated and was protected from the external environment.

  As one form of the reactor of this invention, the core molded object can mention the form provided with the recessed part which accommodates the edge part of an inner core part.

  According to the said structure, the relative positioning of an outer core part and an inner core part can be easily performed only by inserting the edge part of an inner core part in the recessed part of a core molded object. Moreover, in the assembled reactor, it can suppress effectively that the relative position of an outer core part and an inner core part shifts | deviates.

  As one form of the reactor of this invention, it is mentioned that it is set as the form by which the core mold part is not formed in the bottom face which faced the installation object of a reactor among outer core parts.

  By not providing the core mold part at the bottom of the outer core part, the heat dissipation from the outer core part to the installation object such as the cooling base, that is, the heat dissipation from the reactor to the outside can be enhanced.

  As one form of the reactor of this invention, content of the magnetic component of the magnetic powder mixed resin which comprises an inner core part mentions the form which is 20 volume% or more and 75 volume% or less when the whole is 100 volume%. Can do.

  When the magnetic powder is 20% by volume or more, it is easy to ensure magnetic properties such as relative permeability and saturation magnetic flux density. When the magnetic powder is 75% by volume or less, mixing with the resin is easy, and the productivity of the magnetic powder mixed resin is excellent. If such an inner core part is used for a magnetic core, the magnetic core can be hardly magnetically saturated.

  As one form of the reactor of this invention, the outer core part can mention the form which is a compacting body.

  It is easy to increase the content of the magnetic component in the green compact to be higher than the content of the magnetic component in the magnetic powder mixed resin. Therefore, the relative permeability of the green compact is set to be the relative permeability of the magnetic powder mixed resin. It is easy to make it larger than the magnetic susceptibility. In the reactor of the present invention, it is essential that the relative permeability of the outer core portion is larger than the relative permeability of the inner core portion, and the inner core portion is made of a magnetic powder mixed resin. When the molded body is used, the relationship of “relative permeability of outer core portion> relative permeability of inner core portion” can be easily satisfied.

  As one form of the reactor of this invention, the outer core part can mention the form which is magnetic powder mixed resin which disperse | distributed magnetic powder in resin.

  Magnetic powder mixed resin can easily change its magnetic characteristics by changing the ratio of resin and magnetic powder. Therefore, if an outer core part is comprised with a magnetic powder mixed resin, an outer core part provided with a desired magnetic characteristic can be obtained easily.

  As one form of the reactor of the present invention in which the outer core portion is made of a magnetic powder mixed resin, the content of the magnetic component of the magnetic powder mixed resin constituting the outer core portion is 20 volumes when the whole is 100% by volume. The form which is% or more and 75 volume% or less can be mentioned.

  If the outer core portion containing the magnetic component in the above range is used for the magnetic core, the magnetic core can be hardly magnetically saturated.

  As one form of the reactor of the present invention, the relative permeability of the entire magnetic core is 10 or more and 50 or less, the relative permeability of the inner core part is 5 or more and 50 or less, and the relative permeability of the outer core part is 50 or more and 500 or less. Is preferred. The more preferable relative permeability of the entire magnetic core is 10 or more and 35 or less, and the most preferable relative permeability is 10 or more and 30 or less. Here, the relative magnetic permeability of the entire magnetic core is a combination of the inner core portion, the outer core portion, and the portion disposed between the outer core portion and the inner core portion of the core mold portion. The relative permeability. Furthermore, when the gap material is included in the magnetic core, for example, when the inner core portion is composed of a plurality of divided pieces made of a magnetic powder mixed resin and the gap material arranged between the divided pieces, the ratio of the entire magnetic core The magnetic permeability is a relative magnetic permeability including the gap material.

  In addition, the relative magnetic permeability of each said core part here means what was calculated | required as follows. A ring-shaped test piece having an outer diameter of 34 mm, an inner diameter of 20 mm, and a thickness of 5 mm is produced using the same material as the core portion. The test piece is subjected to winding of 300 turns on the primary side and 20 turns on the secondary side, and the BH initial magnetization curve of the test piece is measured in the range of H = 0 to 100 Oersted (Oe). For this measurement, for example, a BH curve tracer “BHS-40S10K” manufactured by Riken Denshi Co., Ltd. can be used. Then, the maximum value of the gradient (B / H) of the obtained BH initial magnetization curve is obtained and used as the relative permeability of the core portion. The magnetization curve here is a so-called DC magnetization curve.

  On the other hand, the saturation magnetic flux density of each of the core portions is the magnetic flux density when a magnetic field of 10,000 (Oe) is applied to the test piece with an electromagnet and sufficiently magnetically saturated.

  A magnetic core satisfying the relative permeability in the above range is less likely to be magnetically saturated when used in a reactor. The relative magnetic permeability in the above range can be easily satisfied by using the outer core portion as a green compact.

  As one form of the reactor of the present invention, the relative permeability of the entire magnetic core is 5 or more and 30 or less, the relative permeability of the inner core part is 5 or more and 25 or less, and the relative permeability of the outer core part is 10 or more and 40 or less. Is preferred.

  A magnetic core satisfying the relative permeability in the above range is less likely to be magnetically saturated when used in a reactor. The relative permeability in the above range can be easily satisfied by using the outer core portion as a magnetic powder mixed resin. It is possible to satisfy the relative magnetic permeability in the above range even when the outer core portion is a green compact.

  The converter of this invention is provided with the reactor of the said invention. For example, the converter of the present invention includes a switching element, a drive circuit that controls the operation of the switching element, and the reactor of the present invention that smoothes the switching operation, and converts the input voltage by the operation of the switching element. A configuration can be mentioned.

  The power converter device of this invention is provided with the converter of the said invention. For example, the power converter of the present invention includes a converter of the present invention that converts an input voltage, and an inverter that is connected to the converter and converts between direct current and alternating current, and the electric power converted by the inverter The form which drives load can be mentioned.

  The converter of the present invention using the reactor of the present invention that is excellent in productivity and the power conversion device of the present invention contribute to the improvement of the productivity of equipment (for example, a vehicle such as a hybrid car) provided with these.

  The reactor of the present invention is hardly magnetically saturated.

1 is a schematic perspective view of a reactor according to a first embodiment. (A) is a front view of the reactor which concerns on Embodiment 1, (B) is a bottom view. 1 is an exploded perspective view of a reactor according to a first embodiment. (A) is a schematic perspective view of the reactor which concerns on Embodiment 2, (B) is a longitudinal cross-sectional view of (A). 1 is a schematic configuration diagram schematically showing a power supply system of a hybrid vehicle. It is a schematic circuit which shows an example of the power converter device of this invention provided with the converter of this invention.

  Hereinafter, embodiments of the present invention will be described more specifically. The same reference numerals in the figure indicate the same names.

<Embodiment 1>
A reactor 1 of the first embodiment shown in FIGS. 1 to 3 is a combination 10 of a coil 2 and a magnetic core 3. The coil 2 of the reactor 1 includes a pair of coil elements 2A and 2B, and the magnetic core 3 includes a pair of inner core portions 31 and 31 and a pair of outer core portions 32 and 32 (see particularly FIG. 3). . As shown in FIG. 3, the reactor 1 is characterized in that a core mold portion 5M that protects the outer core portion 32 is formed on the outer peripheral surface of the outer core portion 32, and of the core mold portion 5M, The part arrange | positioned between the outer core part 32 and the inner core part 31 is functioning as a gap material. Hereinafter, each structure of the reactor 1 of this Embodiment 1 is demonstrated in detail.

≪Coil≫
The coil 2 provided in the combined body 10 (reactor 1) includes a pair of coil elements 2A and 2B and a coil element connecting portion 2r that connects both the coil elements 2A and 2B. The coil elements 2A and 2B are formed in a hollow cylindrical shape with the same number of turns and the same winding direction, and are arranged side by side so that the axial directions are parallel to each other. In the present embodiment, the coil elements 2A and 2B are formed by spirally winding a single winding without a connection portion, and the coil element is bent by a U-shape. A connecting portion 2r is formed. Of course, both the coil elements 2A and 2B may be formed by spirally winding separate windings. In that case, for example, the ends of the coil elements 2A and 2B are joined together by pressure welding or welding. To do.

  As the coil 2, a coated wire having an insulating coating made of an insulating material on the outer periphery of a conductor such as a flat wire or a round wire made of a conductive material such as copper, aluminum, or an alloy thereof can be suitably used. In the present embodiment, the conductor is made of a copper rectangular wire, and the insulation coating is made of a coated rectangular wire made of enamel (typically polyamideimide), and each of the coil elements 2A and 2B uses the covered rectangular wire as edgewise. It is a wound edgewise coil. Moreover, although the end face shape of each coil element 2A, 2B is made into the shape which rounded the rectangular corner | angular part, end face shape can be changed suitably, such as circular shape.

  Both end portions 2a and 2b of the coil 2 (the left side in FIG. 1 and FIG. 3) are extended from the turn forming portion and connected to a terminal member (not shown). An external device (not shown) such as a power source for supplying power is connected to the coil 2 through this terminal member.

≪Magnetic core≫
The magnetic core 3 provided in the combined body 10 (reactor 1) is exposed from the pair of inner core portions 31 and 31 disposed inside the coil elements 2A and 2B and the coil elements 2A and 2B. A pair of outer core portions 32 and 32 (see particularly a dotted circle in FIG. 3) sandwiching 31 from both sides. The relative permeability of the outer core portion 32 is higher than that of the inner core portion 31. Thus, by making the relative permeability of both the core parts 31 and 32 different, the relative permeability of the whole magnetic core 3 can be adjusted, and the magnetic core 3 can be made hard to be magnetically saturated. Here, in the reactor 1 of the present invention, the core mold portion 5M formed on the outer peripheral surface of the outer core portion 32 is used as a gap material between the inner core portion 31 and the outer core portion 32 as described in detail later. It functions and makes the magnetic core 3 more difficult to be magnetically saturated.

An example of preferable relative magnetic permeability of the entire magnetic core 3 and the core portions 31 and 32 constituting the magnetic core 3 is shown below.
The entire magnetic core 3 ... relative permeability = 10 or more and 50 or less, more preferably 10 or more and 35 or less, more preferably 10 or more and 30 or less. Inner core portion 31... Relative permeability = 5 or more and 50 or less, outer core portion 32. Relative permeability = 50 or more and 500 or less

[Inner core]
The inner core portions 31, 31 constituting the magnetic core 3 are a single columnar body having no joints, and are made of a magnetic powder mixed resin in which magnetic powder is dispersed in the resin. The reason why the inner core portions 31 and 31 are made of a magnetic powder mixed resin is that the magnetic powder mixed resin is easy to make a low relative permeability body due to its configuration.

(Magnetic powder mixed resin)
Typically, the magnetic powder mixed resin constituting the inner core portion 31 is obtained by mixing magnetic powder with a resin serving as a binder. As the magnetic powder, a soft magnetic material such as an iron-based material or a rare earth metal, a coating powder including an insulating coating on the soft magnetic material, or the like can be used. In particular, eddy current loss in the magnetic powder mixed resin can be effectively reduced by using the coating powder. Examples of the insulating coating include a phosphoric acid compound, a silicon compound, a zirconium compound, an aluminum compound, and a boron compound. On the other hand, a thermosetting resin such as an epoxy resin, a phenol resin, a silicone resin, or a urethane resin can be used as the resin serving as the binder. In addition, thermoplastic resins such as polyphenylene sulfide (PPS) resin, polyimide resin, and fluororesin, room temperature curable resin, or low temperature curable resin may be used. Further, BMC (Bulk molding compound) in which calcium carbonate or glass fiber is mixed with unsaturated polyester, millable silicone rubber, millable urethane rubber, or the like can also be used.

  When the inner core portions 31 and 31 are formed of magnetic powder mixed resin, typically, injection molding, transfer molding, MIM (Metal Injection Molding), cast molding, magnetic powder and powdered solid resin are used. Press molding or the like can be used. In the case of injection molding, a magnetic powder mixed resin can be obtained by filling a molding material with a mixed material of magnetic powder and resin in a predetermined pressure and molding, and then curing the resin. Also in the case of transfer molding or MIM, the above-mentioned mixed material is filled in a mold and molded. In the case of cast molding, a magnetic powder mixed resin can be obtained by injecting the above-mentioned mixed material into a mold without applying pressure and molding and curing the mixture.

  The average particle size of the magnetic powder in the magnetic powder mixed resin is preferably 1 μm or more and 1000 μm or less, and particularly preferably 10 μm or more and 500 μm or less. The magnetic powder may be a mixture of a plurality of types of powders having different particle sizes. When a magnetic powder having an average particle size satisfying the above range is used as a material, the fluidity is high, and a magnetic powder mixed resin can be produced with high productivity using injection molding or the like.

  In addition to the magnetic powder and resin, the magnetic powder mixed resin may contain powder (filler) made of a nonmagnetic material such as ceramics such as alumina or silica. The filler contributes to improvement in heat dissipation and suppression of uneven distribution of magnetic powder (uniform dispersion). Moreover, since the filler is fine and intervenes between the magnetic particles, a decrease in the ratio of the magnetic powder due to the inclusion of the filler can be suppressed. The content of the filler is 0.2% by mass or more and 20% by mass or less, further 0.3% by mass or more and 15% by mass or less, particularly 0.5% by mass or more and 10% by mass or less when the magnetic powder mixed resin is 100% by mass. When the content is less than or equal to%, the above effect can be sufficiently obtained.

  In the magnetic powder mixed resin, the content of the magnetic powder in the magnetic powder mixed resin is preferably 20% by volume to 75% by volume when the magnetic powder mixed resin is 100%. When the magnetic powder is 20% by volume or more, it is easy to ensure magnetic properties such as relative permeability and saturation magnetic flux density. When the magnetic powder is 75% by volume or less, mixing with the resin is easy, and the productivity of the magnetic powder mixed resin is excellent. The magnetic powder mixed resin can change the magnetic characteristics such as relative permeability by adjusting the content of the magnetic powder or changing the material of the magnetic powder. The content of the magnetic powder is more preferably 40% by volume to 65% by volume. In particular, if the magnetic powder is a material such as iron or Fe—Si alloy, the saturation magnetic flux density of the magnetic powder mixed resin is easily set to 0.8 T or more because the content of the magnetic powder is 40 volume% or more. Further, when the content of the magnetic powder is 65% by volume or less, mixing of the magnetic powder and the resin is easier to perform and the productivity is more excellent.

  As can be seen from the content of the magnetic powder, the magnetic powder mixed resin has a low content of magnetic powder and a low relative magnetic permeability as compared with the green compact. The magnetic powder mixed resin preferably has a relative magnetic permeability of 5 to 50 and a saturation magnetic flux density of 0.6 T or more. The thermal conductivity of the magnetic powder mixed resin is preferably 0.25 W / m · K or more.

[Outer core]
The outer core part 32 in the reactor 1 of this invention is utilized with the form of the core molded object 5, as shown in FIG. The core molded body 5 includes an outer core portion 32 and a core mold portion 5M that covers at least a part of the outer periphery thereof.

  The outer core portion 32 is, for example, a columnar core piece having a substantially dome-shaped upper surface and lower surface, as shown by a dotted circle in the upper left of FIG. For this core piece, a compacted body using soft magnetic powder represented by an iron group metal such as iron or an alloy thereof, a laminated body in which a plurality of magnetic thin plates (for example, electromagnetic steel sheets) having an insulating coating are laminated, etc. Is available. Of course, similarly to the inner core portion 31, the outer core portion 32 can be made of a magnetic powder mixed resin. In the present embodiment, the case where the outer core portion 32 is a green compact will be described as an example. The compacted body is excellent in productivity and has a higher relative magnetic permeability than the magnetic powder mixed resin constituting the inner core portion 31. In addition, the structure which used the outer core part 32 as magnetic powder mixed resin is demonstrated in Embodiment 1-1 mentioned later.

(Green compact)
The green compact can typically be produced by press-molding a magnetic powder having an insulating coating on the surface and then subjecting it appropriately to heat treatment. For compacted green body materials, particles such as iron-based materials and rare-earth metals and other soft magnetic materials with insulating coatings on the surfaces of particles and ferrite powders, thermoplastic resins and other additives such as higher fatty acids The use of a mixed material to which (disappeared by the heat treatment or changed into an insulator) is used. By the above manufacturing method, the soft magnetic particles are covered with an insulating coating (for example, a phosphoric acid compound, a silicon compound, a zirconium compound, an aluminum compound, a boron compound, etc.), and a compacted body in which an insulator is interposed between the particles. Is obtained. The green compact provided with an insulating coating is excellent in insulation and can reduce eddy current loss. When the soft magnetic material is ferrite, the insulation is excellent even if the insulation coating is not provided.

  The average particle size of the magnetic powder used is preferably 1 μm or more and 1000 μm or less, particularly preferably 10 μm or more and 500 μm or less. The magnetic powder may be a mixture of a plurality of types of powders having different particle sizes. When a magnetic powder obtained by mixing a fine powder and a coarse powder is used as a material for a green compact, a saturated magnetic flux density is high and a low-loss reactor is easily obtained. The magnetic powder in the green compact and the powder used for the material have substantially the same size (maintained).

  The content of the magnetic powder (magnetic component) in the green compact is preferably 75% by volume or more and more preferably 80% by volume or more when the green compact is 100%. . Adjustment of the content of the magnetic powder in the green compact is controlled by, for example, the thickness of the insulation coating formed on the surface of the magnetic particles, and the amount of resin and additives added to the magnetic powder during the production of the green compact it can.

  As can be seen from the content of the magnetic powder, since the magnetic component is overwhelmingly larger than the insulating component in the powder compact, the powder compact is a magnetic member having a high relative magnetic permeability and a high saturation magnetic flux density. be able to. It is desirable that the powder compact has a relative permeability of 50 to 500, a saturation magnetic flux density of 1.0 T or more, and a thermal conductivity of 10 W / m · K or more.

  The magnetic properties of the green compact can be adjusted by changing the content of the magnetic powder. Of course, the magnetic properties of the green compact can also be adjusted by changing the material of the magnetic powder. In addition, the magnetic characteristics (particularly, the saturation magnetic flux density) of the green compact can be changed by adjusting the molding pressure during pressure molding. In that case, a compacting body with a high saturation magnetic flux density can be obtained by increasing the molding pressure.

(Core mold part)
Next, the core mold part 5M that covers at least a part of the outer core part 32 described above and protects the outer core part 32 from the external environment will be described. The specific covering region of the core mold part 5M is a part facing at least a part of the outer peripheral surface of the outer core part 32 facing the outer side of the reactor and the inner core part 31 described above. In other words, the other part may be covered with the core mold part 5M or may be an arbitrary part that may not be covered. Here, in the parallel type reactor 1 in which the coil elements 2A and 2B are arranged in parallel, the bottom surface of the outer core portion 32 facing the installation target of the reactor 1 such as a cooling base is an arbitrary portion.

  As described above, the core mold portion 5M may cover the entire periphery of the outer core portion 32, but in this embodiment, covers the portion other than the bottom portion of the outer core portion 32 (see FIG. 2B). reference). This core mold part 5M can protect the outer core part 32 from the external environment. In addition, a portion of the core mold portion 5 </ b> M provided at a location facing the inner core portion 31 on the outer peripheral surface of the outer core portion 32 functions as a gap material between the outer core portion 32 and the inner core portion 31. Due to the presence of the gap material, the magnetic core 3 can be more difficult to be magnetically saturated as compared to the case where there is no gap material.

  As already described, in the reactor 1 of this embodiment, as shown in FIG. 2B, the bottom surface of the outer core portion 32 is exposed from the core mold portion 5M. Therefore, if this reactor 1 is placed on a reactor installation target such as a cooling base, the heat of the reactor 1 generated during use can be efficiently radiated from the bottom surface of the outer core portion 32. The bottom surface and the installation target may be bonded by an adhesive layer. By doing so, it is difficult to form a minute gap between the bottom surface and the installation target, and the heat dissipation efficiency from the bottom surface to the installation target can be improved. Further, by providing the adhesive layer, the reactor 1 can be firmly fixed to the installation target.

  The core mold portion 5M is made of a material having excellent insulating properties. Furthermore, the material constituting the core mold portion 5M is preferably excellent in thermal conductivity. Examples of such materials include thermosetting resins such as epoxy resins, silicone resins, and unsaturated polyesters, and thermoplastic insulating resins such as polyphenylene sulfide (PPS) resins and liquid crystal polymers (LCP). it can. This insulating resin may contain at least one kind of ceramic filler selected from silicon nitride, alumina, aluminum nitride, boron nitride, and silicon carbide, so that the core mold portion 5M Insulation and heat dissipation can be improved.

  The thickness of the core mold portion 5M can be selected as appropriate. Moreover, you may vary thickness by the part which functions as a gap material among the core mold parts 5M, and the other part. For example, the thickness of the portion functioning as the gap material may be about 0.1 to 4.0 mm, and the thickness of the other portion may be about 0.1 to 0.5 mm. Here, in this embodiment, as shown in FIG. 3, the thickness of the portion functioning as the gap material in the core mold portion 5M is made thinner than the other portions, thereby the core mold portion 5M. A pair of recesses 5Mc is formed in a portion facing the inner core portions 31, 31. The end portions of the inner core portions 31 and 31 can be fitted into the recess portions 5Mc and 5Mc. Therefore, the concave portion 5Mc can accurately position the outer core portion 32 and the inner core portion 31 and can effectively prevent the relative positions of the both 31 and 32 from shifting after positioning.

≪Usage≫
Reactor 1 having the above-described configuration has applications where current-carrying conditions are, for example, maximum current (direct current): about 100 A to 1000 A, average voltage: about 100 V to 1000 V, and usage frequency: about 5 kHz to 100 kHz, typically an electric vehicle. It can be suitably used as a component part of a vehicle-mounted power conversion device such as a hybrid vehicle. In this application, it is expected that an inductance satisfying 10 μH or more and 2 mH or less of the inductance when the DC current is 0 A and 10% or more of the inductance when the maximum current is applied is 10% or more can be suitably used.

≪Effect≫
By adopting the configuration described above, for example, the reactor 1 that is hard to be magnetically saturated even when used with a large current of 100 A can be obtained. That is, the relative permeability of the outer core portion 32 is made higher than that of the inner core portion 31, and a gap material (core mold portion 5M) is disposed between the outer core portion 32 and the inner core portion 31. This is because the inductance of the entire magnetic core 3 is adjusted.

  Further, in the configuration of the present embodiment, the outer peripheral surface of the outer core portion 32 is protected from the external environment by the core mold portion 5M serving as a gap material, so that the reactor 1 has resistance to physical impact and oxidizing atmosphere. .

<Embodiment 1-1>
In Embodiment 1, the structure which used the outer core part 32 as the compacting body was demonstrated. On the other hand, the outer core part 32 can also be made into magnetic powder mixed resin.

When the outer core portion 32 is made of a magnetic powder mixed resin, preferable relative magnetic permeability of the entire magnetic core 3 and the core portions 31 and 32 constituting the magnetic core 3 is as follows.
The whole magnetic core 3 ... relative permeability = 5 or more and 30 or less Inner core part 31 ... relative permeability = 5 or more and 25 or less Outer core part 32 ... relative permeability = 10 or more and 40 or less

  Here, the relative permeability of the outer core portion 32 is set to be larger than the relative permeability of the inner core portion 31. In order to make the relative permeability of the outer core portion 32 larger than the relative permeability of the inner core portion 31, the material and / or content of the magnetic powder of each core portion 31, 32 may be changed. For example, the same material may be used for the inner core portion 31 and the outer core portion 32, and the content of the magnetic powder in the outer core portion 32 may be greater than the content of the magnetic powder in the inner core portion 31. In this case, since the material of the magnetic powder is the same in the inner core portion 31 and the outer core portion 32, there is an advantage that the preparation of the magnetic powder is easy. Alternatively, a magnetic powder having a large relative permeability is used for the outer core portion 32, a magnetic powder having a small relative permeability is used for the inner core portion 31, and the content of the magnetic powder in the outer core portion 32 and the inner core portion 31 The content of the magnetic powder is the same. In this case, since the contents of the magnetic powder in both the core portions 31 and 32 are the same, the mixing conditions (for example, the mixing time and the mixing temperature of the magnetic powder and the resin, etc.) when producing both the core portions 31 and 32 are set. Can be the same. When the mixing conditions of both the core parts 31 and 32 are the same, it is possible to reduce the trouble of resetting the mixing conditions when producing each of the core parts 31 and 32, and each core part 31, accompanying the resetting of the mixing conditions. There is an advantage that variation in quality of 32 can be eliminated.

<Embodiment 1-2>
In the first embodiment, the reactor 1 including the combined body 10 has been described. On the other hand, it is good also as a reactor which mounts the assembly 10 on the heat sink. Hereinafter, the structure of the heat sink will be described with reference to FIG.

  The heat radiating plate (not shown) is a plate-like member that functions as a heat radiation path that radiates heat generated in the combined body 10 to the cooling base while supporting the combined body 10. That is, the one surface side of the heat radiating plate is a mounting surface on which the assembly 10 is mounted, and the other surface side is a mounting surface to the cooling base.

  Since the said heat sink is arrange | positioned in the vicinity of the coil 2, it comprises from a nonmagnetic material. Moreover, since a heat sink is utilized for the heat dissipation path | route of the reactor 1, it is comprised from the metal material which is excellent in heat conductivity. That is, the heat dissipation plate is made of nonmagnetic metal such as aluminum or an alloy thereof, or magnesium or an alloy thereof. Since the non-magnetic metals listed above are lightweight, they are suitable as a constituent material for in-vehicle components for which weight reduction is desired. The thickness of the heat radiating plate is preferably about 2 to 5 mm in consideration of strength and magnetic flux shielding properties.

  When using a heat sink, it is preferable to form an adhesive layer (not shown) for bonding the assembly 10 to the heat sink. The adhesive layer has a function of firmly fixing the combined body 10 to the heat sink. In addition, even if there are minute irregularities on the bottom surface of the outer core portion exposed from the core mold portion 5M and the top surface of the heat sink, the adhesive layer can hardly form a gap between the bottom surface and the heat sink. As a result, it is possible to suppress the division of the heat dissipation path due to the gap.

  The adhesive layer is made of an insulating resin having an insulation characteristic that can sufficiently insulate between the coil 2 and the heat radiating plate and a heat resistance that does not soften against the maximum temperature when the reactor 1 is used. To do. For example, a thermosetting resin such as an epoxy resin, a silicone resin, or an unsaturated polyester, or a thermoplastic insulating resin such as a PPS resin or LCP can be suitably used for the adhesive layer. The insulating resin may contain at least one ceramic filler selected from silicon nitride, alumina, aluminum nitride, boron nitride, and silicon carbide, so that the insulating properties of the adhesive layer can be increased. And heat dissipation can be improved. The thermal conductivity of the adhesive layer is preferably 0.1 W / m · K or more, more preferably 0.15 W / m · K or more, still more preferably 0.5 W / m · K or more, and particularly preferably 1 W. / M · K or more, most preferably 2.0 W / m · K or more.

<Embodiment 2>
In the second embodiment, a reactor 1 ′ including a coil 2 ′ having one coil element 2C and a combination 10 ′ of a magnetic core 3 ′ will be described with reference to FIG. In addition, as for this reactor 1 ', the paper surface lower side is an installation surface of a cooling base.

  The coil 2 'of the reactor 1' shown in FIG. 4 includes only one coil element 2C, and end portions 2a and 2b are drawn out from this one coil element 2C.

  The magnetic core 3 ′ of the reactor 1 ′ includes an inner core portion 31 ′ disposed inside the coil element 2 </ b> C and an outer core portion 32 ′ exposed from the coil element 2 </ b> C. The inner core portion 31 ′ is a columnar magnetic body corresponding to the internal shape of the coil element 2 </ b> C, and is made of a magnetic powder mixed resin.

  On the other hand, the outer core portion 32 'is divided into a cylindrical divided piece 32A and a pair of plate-shaped divided pieces 32B and 32C disposed at both ends of the cylindrical divided piece 32A. The relative magnetic permeability of these divided pieces 32A, 32B, 32C is higher than the relative magnetic permeability of the inner core portion 31 '. In order to satisfy such a relationship of the relative magnetic permeability, for example, the divided pieces 32A, 32B, and 32C may be formed into a green compact. Of course, the divided pieces 32A, 32B, 32C may be magnetic powder mixed resin.

  The divided pieces 32A, 32B, 32C are used in the form of a core molded body 5 'having a core mold portion 5M' on at least a part of the outer peripheral surface thereof. A specific formation state of the core mold portion 5M ′ will be described below with reference to FIG.

  First, a core mold portion 5M ′ is formed over the entire circumference of the cylindrical divided piece 32A of the present embodiment. However, the part where the core mold portion 5M 'is essential in the cylindrical divided piece 32A is only the outer wall surface of the cylindrical divided piece 32A. It should be noted that the inner wall surface of the cylindrical divided piece 32A faces toward the inner core portion 31 but is not a surface facing the inner core portion 31 but a surface facing the coil 2. Is

  Next, the core mold part 5M 'is also formed over the entire periphery of the plate-shaped divided piece 32B on the upper side of the drawing. However, in the plate-like divided piece 32B, the core mold portion 5M ′ is essential in the inner core portion 31 among the upper surface, the belt-like wall surface, and the lower surface of the paper surface of the plate-like divided piece 32B. It is the part opposite to '. A concave portion into which the inner core portion 31 ′ is fitted may be formed in the core mold portion 5 </ b> M ′ of the plate-shaped divided piece 32 </ b> B.

  Finally, the plate-shaped divided piece 32C on the lower side of the paper surface has a core mold portion 5M 'formed on a surface other than the lower surface (bottom surface) of the paper surface. However, the part where the core mold part 5M ′ is essential in the plate-like divided piece 32C is the part of the plate-like divided piece 32C facing the inner core part 31 ′ among the band-like wall surface and the upper surface of the sheet. is there. The core mold part 5 ′ of the plate-like divided piece 32 </ b> C may be formed with a recess for fitting the inner core part 31 ′. The reason why the core mold portion 5M 'is not formed on the bottom surface of the divided piece 32C is to improve the heat dissipation of the reactor 1'.

  The reactor 1 ′ described above is not easily magnetically saturated. This is because a part of the core mold part 5M 'that protects the outer core part 32' functions as a gap material between the inner core part 31 'and the outer core part 32'.

<Embodiment 3>
The reactor according to the present invention such as the first embodiment, the first embodiment, the first embodiment, the second embodiment, or the like is, for example, a component of a converter placed on a vehicle or the like, or a power conversion device including the converter. Can be used for components.

  For example, a vehicle 1200 such as a hybrid vehicle or an electric vehicle is used for traveling by being driven by a main battery 1210, a power converter 1100 connected to the main battery 1210, and power supplied from the main battery 1210 as shown in FIG. The motor (load) 1220 is provided. The motor 1220 is typically a three-phase AC motor, which drives the wheel 1250 when traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, vehicle 1200 includes an engine in addition to motor 1220. In addition, in FIG. 5, although an inlet is shown as a charge location of the vehicle 1200, it is good also as a form provided with a plug.

  Power conversion device 1100 includes converter 1110 connected to main battery 1210 and inverter 1120 connected to converter 1110 and performing mutual conversion between direct current and alternating current. Converter 1110 shown in this example boosts the DC voltage (input voltage) of main battery 1210 of about 200V to 300V to about 400V to 700V and supplies power to inverter 1120 when vehicle 1200 is traveling. In addition, converter 1110 steps down DC voltage (input voltage) output from motor 1220 via inverter 1120 to DC voltage suitable for main battery 1210 during regeneration, and causes main battery 1210 to be charged. The inverter 1120 converts the direct current boosted by the converter 1110 into a predetermined alternating current when the vehicle 1200 is running, and supplies the motor 1220 with electric power. During regeneration, the alternating current output from the motor 1220 is converted into direct current and output to the converter 1110. doing.

  As shown in FIG. 6, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor L, and converts input voltage by ON / OFF repetition (switching operation). (In this case, step-up / down pressure) is performed. For the switching element 1111, a power device such as FET or IGBT is used. The reactor L has the function of smoothing the change when the current is going to increase or decrease by the switching operation by utilizing the property of the coil that prevents the change of the current to flow through the circuit. As the reactor L, the reactor described in the above embodiment is used. By using these lightweight and easy-to-handle reactors, the power converter 1100 (including the converter 1110) can be reduced in weight.

  Here, the vehicle 1200 is connected to the converter 1110, the power supply converter 1150 connected to the main battery 1210, and the sub-battery 1230 and the main battery 1210 that are power sources of the auxiliary devices 1240. Auxiliary power supply converter 1160 for converting the high voltage 1210 to a low voltage is provided. The converter 1110 typically performs DC-DC conversion, while the power supply device converter 1150 and the auxiliary power supply converter 1160 perform AC-DC conversion. Some power supply device converters 1150 perform DC-DC conversion. The reactors of the power supply device converter 1150 and the auxiliary power supply converter 1160 have the same configuration as the reactors of the above-described embodiments and modifications, and a reactor whose size and shape are appropriately changed can be used. In addition, the reactor of the above-described embodiment can be used for a converter that performs conversion of input power and that only performs step-up or converter that performs only step-down.

  In addition, this invention is not limited to embodiment mentioned above, It can change suitably in the range which does not deviate from the summary of this invention.

  The reactor of this invention can be utilized for the components of power converters, such as a bidirectional | two-way DC-DC converter mounted in vehicles, such as a hybrid vehicle, an electric vehicle, and a fuel cell vehicle.

DESCRIPTION OF SYMBOLS 1 Reactor 10 Combination 2 Coil 2A, 2B Coil element 2r Coil element connection part 2a, 2b End part 3 Magnetic core 31 Inner core part 32 Outer core part 5 Core molded object 5M Core mold part 5Mc Recess 1 'Reactor 10' Combination 2 'Coil 2C Coil element 2a, 2b End 3' Magnetic core 31 'Inner core 32' Outer core 32A Cylindrical segment 32B, 32C Plate segment 5 'Core molding 5M' Core mold 1100 Power conversion Device 1110 Converter 1111 Switching element 1112 Drive circuit L Reactor 1120 Inverter 1150 Power supply converter 1160 Auxiliary power supply converter 1200 Vehicle 1210 Main battery 1220 Motor 1230 Sub-battery 1240 Auxiliary machinery 1250 Wheel

Claims (10)

A coil, and a magnetic core having a portion inserted through the coil,
The magnetic core is a reactor having an inner core portion disposed inside the coil and an outer core portion exposed from the coil,
The inner core part is a seamless columnar body composed of a magnetic powder mixed resin in which magnetic powder is dispersed in a resin,
The relative permeability of the outer core portion is greater than the relative permeability of the inner core portion,
A core molded body having the outer core portion and a core mold portion protecting the outer core portion;
Of the outer peripheral surface of the outer core portion, at least the portion facing outward of the reactor and the entire surface facing the inner core portion are covered by the core mold portion ,
The core mold part is a reactor including a concave part that houses an end part of the inner core part . The reactor of Claim 1 in which the said core mold part is not formed in the bottom face which faced the installation object of a reactor among the said outer core parts. The content of the magnetic component of the magnetic powder mixed resin constituting the inner core portion, when the whole of the inner core portion is 100 vol%, to claim 1 or claim 2 or less 20% by volume to 75% by volume The described reactor. The reactor according to any one of claims 1 to 3 , wherein the outer core portion is a green compact. The reactor according to any one of claims 1 to 3 , wherein the outer core portion is made of a magnetic powder mixed resin in which magnetic powder is dispersed in a resin. The content of the magnetic component of the magnetic powder mixed resin constituting the outer core portion, when the whole of the outer core portion is 100% by volume, according to Der Ru請 Motomeko 5 or 20 vol% 75 vol% or less Reactor. The outer core has a relative magnetic permeability of 50 or more and 500 or less,
The relative permeability of the inner core portion is 5 or more and 50 or less,
The relative permeability of the entire magnetic core including the outer core portion, the inner core portion, and the portion of the core mold portion that is disposed between the outer core portion and the inner core portion is 10 or more and 50. The reactor according to any one of claims 1 to 4 , which is the following. The outer core has a relative magnetic permeability of 10 to 40,
The relative permeability of the inner core portion is 5 or more and 25 or less,
The relative magnetic permeability of the entire magnetic core including the outer core portion, the inner core portion, and a portion of the core mold portion disposed between the outer core portion and the inner core portion is 5 or more and 30. the reactor as claimed in any one of claims 6 less. A converter provided with the reactor as described in any one of Claims 1-8 . A power converter device comprising the converter according to claim 9 .

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