JP2013179258A - Reactor, converter and power conversion device, and core component for reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor which is highly manufacturable and capable of reducing noise caused by vibration.SOLUTION: A reactor 1a includes a coil molding 20 which is made by covering a cylindrical coil formed by winding a wire 2w with a resin mold part 21, and a magnetic core 3 which is placed inside and outside the coil and which forms a closed magnetic circuit. The magnetic core 3 is provided with an inside core part 31 which is placed inside the coil, and an outside core part 32 which is placed on the outer circumference side of the coil. The outside core part 32 includes a connecting core part 32c, and an end core part 32e. At least a part (connecting core part 32c) of the magnetic core 3 is composed of a composite material which is a mixture of magnetic powder and millable type silicon rubber.

Description

  The present invention relates to a reactor used for a component of a power conversion device such as an in-vehicle DC-DC converter mounted on a vehicle that uses electric power as a drive source such as a hybrid vehicle and an electric vehicle, a converter including the reactor, and The present invention relates to a power conversion device including the converter, and a reactor core component that constitutes a magnetic core included in the reactor. In particular, the present invention relates to a reactor that is highly manufacturable and can reduce noise caused by vibration.

  A reactor is one of the parts of a circuit that performs a voltage step-up operation or a voltage step-down operation. For example, Patent Documents 1 and 2 disclose a reactor used in a converter mounted on a vehicle such as a hybrid vehicle. The reactor includes a cylindrical coil formed by winding a winding, and a magnetic core that is disposed inside and outside the coil to form a closed magnetic circuit. Examples of the shape of the magnetic core include combining a plurality of core parts into an annular core, or combining a plurality of core parts into a pot-type core. The core components that make up the magnetic core include laminated steel sheets laminated with magnetic steel sheets, compacted compacts formed by pressing magnetic powder having an insulating coating on the surface, and composite materials in which magnetic powder and binder resin are mixed. Is being used. In Patent Documents 1 and 2, the portion of the magnetic core that covers the outside of the coil is formed of a mixture (composite material) of magnetic powder and resin.

  Further, the reactor is housed in a case, for example, and housed in a converter case and fixed.

JP 2011-124310 A JP 2011-1992257 A

  Generally, an epoxy resin or a silicone resin is used as a composite material resin. When a part of a magnetic core is formed of a composite material containing such a resin, there are the following problems.

  Conventionally, when part of a magnetic core is formed of a composite material, magnetic powder and the above-mentioned resin having fluidity are mixed, and this mixed fluid is injected into a mold (case) to be molded and cured. . Before curing, since the resin is a fluid liquid, it is difficult to cure in a state where the magnetic powder is uniformly dispersed, for example, the magnetic powder settles. Therefore, the distribution of the magnetic powder in the composite material becomes non-uniform, and it may be difficult to realize the inductance as designed. In order to solve the problem of uneven distribution of the magnetic powder, for example, a non-magnetic powder filler is added to the mixed fluid to suppress sedimentation of the magnetic powder, or the mixed fluid is injected little by little. Although it can be considered that it is formed by being divided into times, it causes a decrease in manufacturability.

  Further, the reactor vibrates when the coil is energized, and the vibration is transmitted from the magnetic core to another constituent member such as a case, and there is a possibility that noise due to the vibration is generated. Furthermore, since the reactor becomes hot during energization, there is a risk that cracks will occur in the composite material due to the difference in thermal expansion coefficient between the magnetic powder and the resin.

  Accordingly, one of the objects of the present invention is to provide a reactor and a core part for the reactor that are highly manufacturable and can reduce noise caused by vibration. Another object of the present invention is to provide a converter including the reactor and a power conversion device including the converter.

  The present invention achieves the above object by using a millable silicone rubber as a resin serving as a binder of a composite material.

  The reactor of the present invention includes a cylindrical coil and a magnetic core that is disposed inside and outside the coil to form a closed magnetic circuit. At least a part of the magnetic core is composed of a composite material in which magnetic powder and resin are mixed. The resin is millable silicone rubber.

  The core part for reactors of this invention comprises the magnetic core with which a reactor is provided. And the core part for reactors of this invention is comprised with the composite material which mixed magnetic powder and resin, and resin is millable type silicone rubber, It is characterized by the above-mentioned.

  According to the reactor and the reactor core part of the present invention, since the resin of the composite material is a millable silicone rubber, the fluidity is low before curing, and the viscosity is higher than that of conventionally used resins. Therefore, after the magnetic powder and the resin (rubber) are kneaded, the magnetic powder is unlikely to settle, and the state in which the magnetic powder is uniformly dispersed in the composite material can be maintained. Therefore, manufacturability is high while realizing the inductance as designed. Further, since the resin in the composite material is rubber, the composite material has elasticity and is soft even after being cured. Therefore, the composite material can absorb vibration and reduce noise due to vibration. Moreover, even if a thermal expansion coefficient difference arises between magnetic powder and resin, it can suppress that a crack arises in a composite material because resin deform | transforms. Furthermore, if the resin of the composite material is a millable type silicone rubber, it has high heat resistance and hardly deteriorates even at high temperatures.

  When at least a part of the magnetic core is formed of the composite material, at least a part of the magnetic core disposed at the outside of the coil (that is, a part exposed from the coil) may be formed of the composite material. Alternatively, the portion disposed inside the coil may be formed of this composite material, and the entire magnetic core may be formed of this composite material.

  In the present invention, a millable silicone rubber is substantially used as the resin serving as the binder of the composite material. The millable silicone rubber in the composite material is a rubber (polymer polymer) having an elasticity of 100% or more after curing, and the Young's modulus at room temperature (25 ° C.) is about 0.1 to 50 MPa. By satisfying this range, it is possible to obtain a vibration absorbing effect and a crack suppressing effect while maintaining the shape as a composite material. On the other hand, the resin used for the conventional composite material has a Young's modulus after curing of about 3.0 to 30 GPa in the case of an epoxy resin. The cured millable silicone rubber is mainly composed of a linear polymer having a polymerization degree of 3000 to 10000, while the conventional cured silicone resin is mainly composed of a linear polymer having a polymerization degree of 100 to 2000. .

  The composite material can be obtained by blending magnetic powder and millable silicone rubber before curing and kneading. Moreover, in order to bridge | crosslink between chain polymers and to improve elasticity and intensity | strength, it hardens | cures by adding a hardening | curing agent (vulcanizing agent) and heating. As the vulcanizing agent, for example, a peroxide vulcanizing agent can be used. The curing temperature is usually 150 to 200 ° C., and the curing time is usually 5 to 60 minutes. However, when a vulcanizing agent is added, since low molecular siloxane remains in the rubber component after curing, it is preferable to perform heat treatment after curing in order to remove the low molecular siloxane. Low molecular weight siloxane is known to cause contact failure, and if low molecular weight siloxane remains in the composite material, low molecular weight siloxane is generated from the composite material, and the electronic components placed around the reactor May cause problems such as contact failure. Therefore, by reducing the amount of low molecular siloxane in the composite material, it is possible to suppress the generation of low molecular siloxane and avoid problems such as contact failure. Moreover, crosslinking can be promoted by heat treatment, and the strength can be further increased.

  When forming the portion of the magnetic core that is disposed outside the coil with a composite material, for example, a composite in which the magnetic powder and millable silicone rubber are mixed in a state where the coil is disposed at a predetermined position of the mold (case). It can be formed by filling a material, or formed by sticking a composite material to the outside of a coil. In the former case, the composite material is filled and then cured. In the latter case, the composite material before curing may be pasted and then cured, or the composite material after curing molding may be pasted. Moreover, the core part for reactors is made into the molded object of the composite material which pressed the composite material to the metal mold | die and press-molded to the predetermined shape, for example. As the molding method, compression molding, injection molding, transfer molding, extrusion molding, or the like can be used. In this case, it can be cured simultaneously with molding. The heat treatment may be performed after the composite material is disposed (attached) to the coil and a part of the magnetic core is formed of the composite material, or may be performed on a molded body of the composite material.

  Examples of the heat treatment include holding for 30 minutes to 4 hours in a state heated to 150 ° C. or higher and 220 ° C. or lower. By setting the heating temperature to 150 ° C. or more and the holding time to 30 minutes or more, an effect of reducing low molecular siloxane remaining in the composite material can be easily obtained. In addition, when the heating temperature is set to 220 ° C. or lower, when heat treatment is performed including other components such as a coil, the influence on other components can be suppressed. On the other hand, from the viewpoint of production efficiency, the holding time is preferably 4 hours or less.

  As one form of the reactor of this invention, and core part for reactors, it is mentioned that content of the magnetic powder in a composite material is 30 volume% or more and 75 volume% or less.

  When the composite material is 100%, the magnetic powder content is 30% by volume or more, so that it is easy to ensure magnetic characteristics such as saturation magnetic flux density. On the other hand, when the content of the magnetic powder is 75% by volume or less, mixing with a resin (millable silicone rubber) can be easily performed, the productivity can be improved, and the magnetic powder can be easily dispersed uniformly. The lower limit of the content of the magnetic powder in the composite material is more preferably 40% by volume or more, the upper limit is more preferably 65% by volume or less, and further preferably 60% by volume or less. For example, when a magnetic powder containing iron as a main component is used as the magnetic powder, a saturation magnetic flux density of 0.6 T or more can be easily obtained by setting the content of the magnetic powder in the composite material to 30 volume% or more, and 40 volume%. By setting it as the above, it is easy to obtain the saturation magnetic flux density of 0.8T or more. On the other hand, by setting the content of the magnetic powder in the composite material to 65% by volume or less, it is easier to mix the magnetic powder and the resin, and it is easier to disperse the magnetic powder more uniformly. Furthermore, by setting it to 60% by volume or less, it is easier to mix the magnetic powder and the resin, and it is easier to disperse the magnetic powder more uniformly.

  As one form of the reactor of the present invention, the coil includes a pair of coil elements arranged side by side.

  According to this aspect, when a coil (coil element) is formed by spirally winding a winding, the number of turns (turns) is the same as that of a coil constituted by one linear coil element. In this case, the length from one end side of the coil (both coil elements) to the other end side can be shortened. Therefore, the reactor can be downsized.

  As one form of the reactor of this invention, it is mentioned that at least one part of the location arrange | positioned outside a coil is comprised with the said composite material among magnetic cores.

  In this case, a part of the magnetic core (placed outside the coil) can be formed by pasting or arranging the composite material on the outside of the coil. Here, in the magnetic core, the portion disposed on the outer peripheral side of the coil is, for example, a composite material pasted on the outer peripheral side of the coil, or a cylindrical body formed in advance in a cylindrical shape from a composite material. It is also possible to form by attaching to the. On the other hand, a portion of the magnetic core that is disposed inside the coil may be formed of a composite material. In this case, for example, the magnetic material is formed by inserting a columnar body formed by columnar composite material into the coil. It is possible. Thus, the manufacturing process of a reactor can be simplified by producing the core part of a cylindrical body or a columnar body beforehand with a composite material. In addition, in the magnetic core, a portion (hereinafter referred to as an outer core portion) disposed outside the coil is made of the composite material, so that vibration transmitted from the outer core portion to another constituent member such as a case can be prevented. The outer core portion itself absorbs and noise caused by vibration can be effectively reduced.

  As one form of the reactor of this invention, the location arrange | positioned inside a coil among magnetic cores is comprised by the compacting body.

  According to this embodiment, in the magnetic core, the portion disposed inside the coil (hereinafter referred to as the inner core portion) is configured by the green compact, and at least a part of the portion disposed outside the coil is the above-described portion. By being comprised with a composite material, it is easy to design so that the saturation magnetic flux density of an inner core part may become higher than an outer core part. Since the cross-sectional area of the inner core portion can be reduced by increasing the saturation magnetic flux density of the inner core portion, the reactor can be reduced in size. In addition, it is easy to design the relative permeability of the outer core portion to be lower than that of the inner core portion, and by adjusting the relative permeability of the entire magnetic core by reducing the relative permeability of the outer core portion, for example, The magnetic core can have a gapless structure. Leakage magnetic flux can be reduced by using a gapless structure.

  As one form of the reactor of this invention, it is mentioned that the whole magnetic core is comprised with the said composite material.

  According to this embodiment, not only the outer core portion but also the inner core portion is composed of the composite material, so that vibration transmitted from the inner core portion to another component member such as a case via the coil can be transmitted to the inner core portion. It absorbs itself and noise caused by vibration can be reduced more effectively. In addition, since only the composite material is used as the material of the magnetic core, it is not necessary to use another material, and the manufacturing cost can be reduced.

  The reactor of this invention can be utilized suitably for the component of a converter. The converter of the present invention includes the reactor of the present invention described above. The converter includes a switching element, a drive circuit that controls the operation of the switching element, and a reactor that smoothes the switching operation, and converts the input voltage by the operation of the switching element.

  Moreover, the converter of this invention can be utilized suitably for the component of a power converter device. The power converter of the present invention includes the above-described converter of the present invention. Examples of the power conversion device include a converter that converts an input voltage and an inverter that is connected to the converter and converts DC and AC to each other, and a load is driven by the power converted by the inverter. .

  The converter and the power converter of the present invention include the above-described reactor of the present invention that can reduce noise caused by vibrations, and thus have excellent quietness and can be suitably used for in-vehicle components.

  Since the resin of the composite material is a millable silicone rubber, the reactor and the core part for the reactor of the present invention are highly manufacturable. Moreover, the converter and power converter device of this invention can be suitably utilized for the vehicle-mounted components etc. to which cost reduction is calculated | required by providing the reactor of above-described this invention.

1 is a schematic perspective view of a reactor according to a first embodiment. 1 is a schematic exploded perspective view of a reactor according to a first embodiment. FIG. 3 is a schematic perspective view of a coil molded body provided in the reactor according to the first embodiment. It is a schematic perspective view of the reactor which concerns on Embodiment 2. FIG. FIG. 5 is a schematic exploded perspective view of a reactor according to a second embodiment. 6 is a schematic perspective view of a coil molded body included in a reactor according to Embodiment 2. FIG. It is a schematic perspective view of the reactor which concerns on Embodiment 3. FIG. FIG. 5 is a schematic exploded perspective view of a reactor according to a third embodiment. It is a schematic perspective view of the coil molded object with which the reactor which concerns on Embodiment 3 is provided. It is a schematic perspective view of the reactor which concerns on Embodiment 6. FIG. FIG. 10 is a schematic exploded perspective view of a reactor according to a sixth embodiment. It is a schematic perspective view of the reactor which concerns on Embodiment 7. FIG. 1 is a schematic configuration diagram schematically showing a power supply system of a hybrid vehicle. It is a schematic circuit diagram which shows an example of this invention power converter device which provides this invention converter.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the figure indicate the same names. In the following description, when the reactor is installed on the installation target, the installation side is described as the lower side, and the opposite side (opposite side) is described as the upper side.

Embodiment 1
The reactor according to the first embodiment will be described with reference to FIGS. The reactor 1a includes a coil 2 (see FIG. 3) formed by winding a winding 2w, and a magnetic core 3 disposed inside and outside the coil 2 to form a closed magnetic circuit. The reactor 1a is typically used by being installed on an installation target such as a cooling base, and stored in a case (not shown) as necessary. The cooling base typically includes a cooling mechanism such as a circulation path through which a fluid refrigerant such as cooling water is circulated. The magnetic core 3 includes a columnar inner core portion 31 disposed inside the coil 2 and an outer core portion 32 disposed outside the coil 2. This reactor 1a is characterized in that at least a part of the magnetic core 3 is composed of a composite material in which magnetic powder and a resin are mixed, and this resin is a millable silicone rubber. Hereinafter, each component will be described in more detail.

[coil]
As shown in FIG. 3, the coil 2 is a cylindrical body formed by spirally winding a single continuous winding 2w, and is composed of one coil element. The winding 2w is preferably a coated wire having an insulating coating made of an insulating material (typically an enamel material such as polyamideimide) on the outer periphery of a conductor made of a conductive material such as copper, aluminum, or an alloy thereof. The conductor may have various shapes such as a rectangular wire having a rectangular cross section, a round wire having a circular shape, and a deformed wire having a polygonal shape. Here, the coil (coil element) 2 is an edgewise coil formed by edgewise winding a coated rectangular wire whose conductor is made of a copper rectangular wire and whose insulating coating is made of enamel. The edgewise coil is easy to make a small coil by increasing the space factor, and contributes to the miniaturization of the reactor.

  The end surface shape of the coil 2 (= the cross-sectional shape in the direction orthogonal to the axis of the coil 2) is typically a circular shape as shown in FIG. Cylindrical coils are easy to wind even when a rectangular wire is used for the winding, and are excellent in coil manufacturability and easy to be made into a small coil. The end face shape of the coil 2 may be non-circular. For example, combining a straight line and a curve such as an ellipse or the like, a shape consisting essentially only of a curve, a shape obtained by rounding each corner of a polygon (for example, a rectangle), or a racetrack shape formed by combining a straight line and an arc. And the like.

  As shown in FIG. 1 and the like, both end portions of the winding 2w forming the coil 2 are appropriately extended from the turn portion and pulled out from the outer core portion 32, and the exposed conductor is peeled off from the insulation coating. A terminal member (not shown) made of a conductive material such as copper or aluminum is connected. An external device (not shown) such as a power source for supplying power is connected to the coil 2 via the terminal member, and the coil 2 can be energized. For connection between the conductor of the winding 2w and the terminal member, welding such as TIG welding or crimping can be used. Here, both ends of the winding 2w are bent so that both ends of the winding 2w are pulled out in parallel with the axial direction of the coil 2 at one end of the coil 2. It should be noted that the drawing direction of both ends of the winding 2w is an example, and can be changed as appropriate.

  When the reactor 1a is installed on an installation target such as a cooling base or a case, the reactor 1a can be placed horizontally (horizontal arrangement form) so that the axial direction of the coil 2 is substantially parallel to the installation target installation surface. The coil 2 can be placed vertically (vertical arrangement form) so that the axial direction of the coil 2 is substantially orthogonal to the installation surface.

[Coil molding]
Although the coil 2 can be used as it is, a coil molded body 20 in which the surface of the coil 2 is covered with a resin mold portion 21 made of an insulating resin is used here. The resin mold portion 21 has a function of holding the coil 2 in a certain shape, and the coil 2 does not expand and contract during assembly of the reactor and the handling of the coil 2 becomes easy. Further, the resin mold part 21 has a function of improving the insulation between the coil 2 and other constituent members (magnetic core 3) disposed in the periphery thereof.

  As shown in FIG. 1 and the like, the resin mold portion 21 is provided at a location where the winding 2w that forms the coil 2 is in contact with the magnetic core 3, and the entire turn portion (the inner peripheral surface and the outer peripheral surface of the winding 2w). , As well as both end faces) and both ends of the winding 2w (excluding the part pulled out from the outer core part 32). However, the covering region of the coil 2 by the resin mold portion 21 can be appropriately selected. For example, a part of the turn portion of the winding 2w is not covered with the resin mold portion 21, and may be exposed. However, as in this example, when the entire surface of the turn part of the winding 2w is substantially covered with the resin mold part 21, the coil 2 and the inner core part 31 or between the coil 2 and the outer core part 32 are used. Insulating resin can be surely interposed between the coil 2 and the insulation against the coil 2 can be improved.

  The resin mold part 21 has a function of holding the coil 2 and the inner core part 31 together. The coil molded body 20 is formed by integrally molding the coil 2 and the inner core part 31 by the resin mold part 21. Yes. By using such a coil molded body 20, when assembling the reactor 1a, the number of parts can be reduced and the assembly workability is excellent. Further, by adjusting the thickness of the resin mold portion 21 interposed between the inner peripheral surface of the coil 2 and the outer peripheral surface of the inner core portion 31, in addition to improving the insulation, the inner core portion 31 of the coil 2 Positioning can also be performed. Here, the thickness of the resin mold part 21 interposed between the coil 2 and the inner core part 31 is uniform, and the coil 2 and the inner core part 31 are arranged coaxially by this insulating resin. . Further, the thickness of the resin mold portion 21 covering the outer peripheral surface and end surface of the coil 2 is also substantially uniform.

  The thickness of the resin mold part 21 can be selected as appropriate, and examples thereof include about 0.1 mm to 10 mm. As the thickness of the resin mold portion 21 is increased, the insulation can be improved, and as the thickness is reduced, the heat dissipation can be improved. The thickness is preferably about 0.1 mm to 3 mm. Here, the outer shape of the resin mold portion 21 is a shape along the outer shape of the coil 2, that is, a shape similar to that of the coil 2, and the insulating resin has a substantially uniform thickness over the entire coil molded body 20. It exists. Note that the thickness of the resin mold portion 21 may be partially different as long as a desired function (insulation characteristics, shape retention, etc.) is satisfied. For example, the coil 2 is cylindrical, and the outer shape of the resin mold portion 21 can be a prismatic shape (in this case, the thickness of the insulating resin at the corner portion tends to be thick).

  In addition, the resin mold part 21 has a function of holding the coil 2 in a compressed state from the free length as necessary, so the length of the coil 2 can be made shorter than the natural length, contributing to the downsizing of the reactor. To do.

  In addition, both end surfaces 31e of the inner core portion 31 and the vicinity thereof are exposed without being covered with the resin mold portion 21, and both end surfaces 31e of the inner core portion 31 are in contact with the outer core portion 32. At least one end face 31e of 31 may be covered with the resin mold part 21. At this time, the resin mold portion 21 covering the end surface 31e of the inner core portion 31 functions as a gap.

  The insulating resin that forms the resin mold part 21 has insulation properties that can sufficiently insulate the coil 2 and the magnetic core 3, and heat resistance that does not soften against the maximum temperature when the reactor 1a is used. Resin that can be used for transfer molding or injection molding can be suitably used. For example, thermosetting resins such as epoxy resins, silicone resins, and unsaturated polyesters, and thermoplastic resins such as polyphenylene sulfide (PPS) resins and liquid crystal polymers (LCP) can be suitably used. In addition, when the resin mold portion 21 is made by mixing a filler made of at least one ceramic selected from silicon nitride, alumina, aluminum nitride, boron nitride, and silicon carbide with an insulating resin, an insulating property is obtained. In addition to excellent heat dissipation. For example, a material having a thermal conductivity of 1 W / m · K or more, more preferably 2 W / m · K or more is preferred because of its excellent heat dissipation. Here, an epoxy resin (thermal conductivity: 2 W / m · K) containing a filler in the resin mold portion 21 is used.

  For the manufacture of the coil molded body 20 including the resin mold portion 21, for example, a manufacturing method described in Japanese Patent Application Laid-Open No. 2009-218293 can be used, and various methods such as injection molding, transfer molding, and cast molding can be used. The molding method can be used. By disposing the inner core portion 31 together with the coil 2 in the molding die, the coil molded body 20 including the coil 2, the resin mold portion 21, and the inner core portion 31 can be manufactured. In addition, it can be set as the coil molded object which has the coil 2 and the resin mold part 21 which does not have the inner core part 31, ie, the coil 2. FIG. In this case, it is good to manufacture a coil molded object using a core instead of the inner core part 31. FIG. In the coil molded body, by adjusting the thickness of the resin mold portion 21 provided inside the coil 2, the resin mold portion 21 can be used for positioning the inner core portion 31 as described above.

  A higher voltage may be applied to the end portion (leading portion) of the winding 2w extended from the turn portion of the winding 2w in the coil 2 as compared to the turn portion. Therefore, at least the contact portion with the magnetic core 3 (outer core portion 32) among the lead-out portions of the winding 2w is covered with the resin mold portion 21, or is made of insulating paper, insulating tape (for example, polyimide tape), insulating film. When an insulating material such as polyimide film is appropriately wound, the insulating material is dip-coated, or an insulating tube (either a heat-shrinkable tube or a room-temperature-shrinkable tube) is placed, the coil 2 and the magnetic core 3 (especially here, the outer core portion 32) can be improved in insulation.

[Magnetic core]
As shown in FIGS. 1 and 2, the magnetic core 3 includes a columnar inner core portion 31 inserted inside the cylindrical coil 2 and at least one end surface 31e (here, both end surfaces) of the inner core portion 31. And an outer core portion 32 disposed on the outer peripheral side of the coil 2 to form a closed magnetic circuit when the coil 2 is excited. In the reactor 1a, at least a part of the magnetic core 3 (in this example, at least a part of the outer core 32 disposed on the outer peripheral side of the coil 2 in the magnetic core 3) is a mixture of magnetic powder and resin. Consists of composite materials. In addition, millable silicone rubber is used for the resin of the composite material.

(Inner core part)
The inner core portion 31 is a cylindrical body along the inner peripheral shape of the coil 2. The inner core portion 31 is slightly longer than the length of the coil 2 in the axial direction. When the inner core portion 31 is inserted and arranged in the coil 2, the both end surfaces 31e of the inner core portion 31 and the outer peripheral surface in the vicinity thereof are slightly from the end surface of the coil 2. It protrudes, and this state is maintained by the resin mold part 21. In the inner core portion 31, a length protruding from each end face of the coil 2 (hereinafter referred to as a protruding length) can be selected as appropriate. Here, the protruding lengths are made equal, but may be different, and the length of the inner core portion and the inner core portion relative to the coil may be such that the protruding portion exists only from one end surface of the coil 2. The arrangement position can be adjusted. For example, the protruding length on the one end surface side of the inner core portion 31 can be lengthened so that the one end surface is exposed from the outer core portion 32. The length of the inner core portion and the length of the coil may be equal, and the length of the inner core portion may be shorter than the length of the coil, but the length of the inner core portion 31 is equal to or greater than the length of the coil 2 It is preferable that the magnetic flux generated by the coil 2 can be sufficiently passed through the inner core portion 31.

  The magnetic core 3 can be entirely formed of a uniform material or can be partially different in material. Here, the magnetic core 3 is partially formed of different materials, and the inner core portion 31 is formed of a compacted body.

  The green compact is typically made of an insulating material (eg, silicone resin or phosphorous) on the surface of soft magnetic particles made of a soft magnetic material (eg, iron-based material (iron group metal or iron alloy), rare earth metal, etc.). After pressure molding, soft magnetic powder having an insulating coating made of acid salt, etc., or mixed powder in which a binder (for example, a resin such as a thermoplastic resin or higher fatty acid) is appropriately mixed in addition to this soft magnetic powder It can be produced by appropriately performing a heat treatment. Distortion introduced into the soft magnetic particles during molding can be removed by heat treatment, and a low-loss compact can be obtained. The higher the heat treatment temperature, the more the strain can be removed. The binder is lost by the heat treatment or changed into an insulator such as silica. 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 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 green compact can be molded relatively easily even in a complicated three-dimensional shape, and it is easier to increase the saturation magnetic flux density than the composite material forming the outer core portion 32. For example, by adjusting the material of the soft magnetic material, the mixing ratio of the soft magnetic powder and the binder, the amount of various coatings including the insulating coating, etc., or adjusting the molding pressure, Magnetic characteristics (especially saturation magnetic flux density) can be changed. By using soft magnetic powder with high saturation magnetic flux density (iron-based material is preferred over ferrite), increasing the proportion of soft magnetic material by reducing the amount of binder, etc., or increasing the molding pressure A green compact with a high saturation magnetic flux density is obtained. A well-known thing can be utilized for a compacting body. The content of the magnetic powder in the green compact is preferably more than 75% by volume and more preferably 80% by volume or more when the green compact is 100%.

  The columnar inner core portion 31 can be formed as an integral body formed by using a mold having a desired shape, or can be formed as a laminated body in which a plurality of core pieces made of a compacted body are laminated. A laminated body can be fixed with an adhesive, an adhesive tape, or the like to be an integrated object. Here, the inner core portion 31 is a solid body in which no gap material or air gap is interposed. In addition to being able to reduce the size by not having a gap, the leakage magnetic flux in the gap does not affect the coil 2, so the coil 2 and the inner core part 31 can be brought close to each other (the thickness of the resin mold part 21 can be reduced). ) From this point, the reactor 1a can be made smaller. Furthermore, by omitting the gap, it is possible to reduce loss and decrease in inductance when energizing a large current. The magnetic core 3 can be in a form in which a gap material made of a nonmagnetic material such as an alumina plate or an air gap is interposed.

(Outer core part)
As shown in FIGS. 1 and 2, the outer core portion 32 covers the coil molded body 20 (specifically, both end surfaces constituted by the resin mold portion 21 covering the end surface of the coil 2 and the outer peripheral surface of the coil 2). The outer peripheral surface constituted by the resin mold portion 21, the both end surfaces 31e of the inner core portion 31 and the vicinity thereof are covered. The outer core portion 32 includes a connecting core portion 32c and an end core portion 32e. The connecting core portion 32c is disposed on the outer peripheral surface composed of the resin mold portion 21 that covers the outer peripheral surface of the coil 2. The end core portion 32e is disposed on both end surfaces constituted by the resin mold portion 21 covering the end surface of the coil 2, the both end surfaces 31e of the inner core portion 31, and the vicinity thereof. The magnetic core 3 forms a closed magnetic path by being provided so that a part of the outer core portion 32 is connected to both end faces 31e of the inner core portion 31.

  The outer core portion 32 (the connecting core portion 32c and the end core portion 32e) is made of a composite material obtained by mixing magnetic powder and resin.

  The resin constituting the composite material is millable silicone rubber and functions as a binder. This composite material can be typically obtained by blending magnetic powder and a millable silicone rubber before curing, kneading, and curing.

  The connecting core portion 32c is formed by sticking a composite material obtained by kneading magnetic powder and millable silicone rubber to the outer peripheral surface of the coil molded body 20. Specifically, as shown in FIG. 2, it was formed by winding the composite material so that the lower side of the outer peripheral surface of the coil molded body 20 was exposed. By forming the connecting core portion 32c so that a part of the outer peripheral surface of the coil molded body 20 (here, the lower side) is exposed, it is easy to dissipate heat from this surface to the heat dissipation object, and heat dissipation from the coil 2 is improved. Can be improved. At this time, the composite material may be cured after being attached to the outer peripheral surface of the coil molded body 20 in a state before curing, or the composite material may be cured and molded and then applied to the outer peripheral surface of the coil molded body 20. Also good. Further, the inner peripheral surface of the composite material is provided with irregularities corresponding to the outer shape of the coil molded body 20 (cross-sectional outer shape in the direction perpendicular to the axis of the coil 2). The connection core portion 32c is in close contact with the inner peripheral surface so as not to form a gap. Or, after filling the concave portion of the outer peripheral surface of the coil molded body 20 with a composite material so that the outer shape of the coil molded body 20 is smooth, by further winding the composite material from above to form the connecting core portion 32c, A gap may not be formed between the coil molded body 20 and the connecting core portion 32c. Here, the connecting core portion 32c is formed of one composite material. However, the connecting core portion 32c may be divided in the axial direction or the circumferential direction. When the connecting core portion 32c is divided in the axial direction, the bonding material is bonded so as to be connected in the axial direction. It is better to connect with agents, primers and adhesive tape. On the other hand, when dividing in the circumferential direction, it is easy to arrange the composite material in close contact with the outer shape of the coil molded body 20, and the adjacent composite materials in the circumferential direction may or may not be connected. For example, the average thickness of the connecting core portion 32c is 2 mm or more and 20 mm or less.

  Since the composite material itself has adhesiveness with a resin (millable silicone rubber), it is possible to form the connecting core portion 32c by pasting it on the outer peripheral surface of the coil molded body 20, In order to tightly fix the core portion 32c to the coil molded body 20, the core portion 32c may be fixed with an adhesive, a primer, an adhesive tape, or the like. In addition, the periphery of the connecting core portion 32c may be fastened and fixed with a band or the like. In addition, the connecting core portion 32c is slightly shorter than the axial length of the coil 2, and in a state where the connecting core portion 32c is disposed on the outer peripheral surface of the coil molded body 20, both end surfaces of the coil molded body 20 and the outer peripheral surface in the vicinity thereof are connected cores. It slightly protrudes from the end face of the portion 32c.

  The end core portion 32e is a composite material molded body (reactor core component) obtained by pressing the composite material against a mold and press-molding the composite material into a predetermined shape. As the molding method, compression molding, injection molding, transfer molding, extrusion molding, or the like can be used. The end core portion 32e is formed in a substantially disc shape. As shown in FIG. 2, an inner core portion placement groove 321 and a coil placement groove 322 are formed on the end face of the coil molded body 20 and the inner face of the end core portion 32 e facing the end face 31 e of the inner core portion 31. ing. The inner core portion arrangement groove 321 is fitted with a protruding portion of the inner core portion 31 protruding from the end surface of the coil 2 (coil molded body 20). The coil placement groove 322 is fitted with a protruding portion of the coil molded body 20 protruding from the end surface of the connecting core portion 32c. Accordingly, the end core portion 32e can be easily positioned and the assembly workability is excellent. The end core portion 32e disposed on one end side of the coil molded body 20 (that is, the side from which both end portions of the winding 2w are pulled out) is provided with a drawing hole 323 for pulling out both end portions of the winding 2w. It has been. Similarly to the end core portion 32e, the connecting core portion 32c may be a molded body of a composite material that is press-formed into a predetermined shape (for example, a substantially cylindrical shape).

  Here, as shown in FIG. 1 and FIG. 2, both end surfaces of the connecting core portion 32 c and the inner surface edge of the end core portion 32 e are connected so as to be connected, and the connecting core portion 32 c is integrated. The outer shape of the end core portion 32e (the sectional outer shape in the direction orthogonal to the axis of the coil 2) is the same. As another form, at least one end portion of the connecting core portion 32c protrudes from the end surface of the coil (coil molded body), a recess is formed inside the protruding portion, and the end core portion 32e is formed in the recess. Can be integrated by connecting the inner peripheral surface of the end portion of the connecting core portion 32c and the outer peripheral surface of the end core portion 32e. The connecting core portion 32c and the end core portion 32e may be connected by an adhesive, a primer, an adhesive tape, or the like, and the periphery of the connecting core portion 32c and the end core portion 32e is fastened with a band or the like. Also good. The connecting core portion 32c and the end core portion 32e are both formed of a composite material, and have adhesiveness with a resin (millable silicone rubber), so that they are connected by bonding them together. It is also possible. Similarly, the end core portion 32e and the inner core portion 31 can be connected with an adhesive or the like. The outer core portion 32 also has no gap material or air gap, and the magnetic core 3 has a gapless structure in which no gap is provided over the entire core portion 32.

  Further, the connecting core portion 32c and the end core portion 32e are separate members, and the two are connected and integrated to constitute the outer core portion 32, but when the reactor 1a includes a case, The outer core portion 32 may be formed by using this case as a molding die (casting) for the outer core portion 32. Specifically, in a state where the coil molded body 20 in which the coil 2 and the inner core portion 31 are integrated is disposed at a predetermined position of the case, the case is filled with the composite material, thereby connecting the connecting core portion 32c and the end. It is possible to form the outer core part 32 in which the part core part 32e is integrated. In this case, the outer core portion 32 and the inner core portion 31 can be joined with the composite resin simultaneously with the molding of the outer core portion 32.

  A vulcanizing agent is added to the composite material in order to improve the elasticity and strength of the millable silicone rubber. However, when a vulcanizing agent is added, since low molecular siloxane remains in the rubber component after curing, heat treatment is preferably performed after curing in order to remove the low molecular siloxane. Examples of the heat treatment include holding for 30 minutes to 4 hours in a state heated to 150 ° C. or higher and 220 ° C. or lower. This heat treatment may be performed with the connecting core portion 32c and the end core portion 32e attached to the coil molded body 20, that is, with the magnetic core 3 assembled, or may be performed on a composite material molded body. Good.

  The magnetic powder of the composite material may have the same composition as or a different composition from the soft magnetic powder constituting the inner core portion 31 described above. Since the composite material contains a non-magnetic resin (here, a millable silicone rubber), even if the soft magnetic powder in the composite material and the soft magnetic powder constituting the green compact have the same composition, The saturation magnetic flux density is lower than that of the powder compact, and the relative permeability is also low. Therefore, the relative permeability of the outer core portion 32 can be made lower than that of the inner core portion 31.

  The composite magnetic powder may be a single type or a mixture of multiple types of powders of different materials. The magnetic powder in the composite material constituting the outer core portion 32 is preferably made of an iron-based material such as pure iron powder or iron alloy powder. When the magnetic powder of the composite material is also composed of a metal material, such as an iron-based material, the coating powder having the above-described insulating coating as in the case of the compacted body, Insulation can be enhanced and eddy current loss can be reduced.

  The average particle size of the magnetic powder in the composite material is 1 μm or more and 1000 μm or less, and particularly 10 μm or more and 500 μm or less. The magnetic powder may contain a plurality of types of powders having different particle sizes. When a magnetic powder in which fine powder and coarse powder are mixed is used as a raw material for a composite material, a saturation magnetic flux density is high and a low-loss reactor is easily obtained. Note that the magnetic powder in the composite material and the powder used for the raw material are substantially the same size (maintained), and if the magnetic powder satisfying the above range is used as the raw material, the flowability is reduced. The magnetic powder is easily dispersed uniformly in the composite material, and the composite material is excellent in manufacturability.

  The content of the magnetic powder in the composite material is desirably 30% by volume or more and 75% by volume or less by volume when the composite material is 100%. When the magnetic powder is 30% by volume or more, it is easy to ensure magnetic characteristics such as the saturation magnetic flux density of the outer core portion 32, and hence the entire magnetic core 3. When the magnetic powder is 75% by volume or less, it is easy to mix with the resin, and the productivity of the composite material is excellent.

  In addition, in addition to magnetic powder and resin (millable silicone rubber), the composite material may be mixed with a filler, typically a powder of a non-magnetic material such as ceramics such as alumina or silica. Mixing a filler having excellent thermal conductivity such as ceramics can contribute to improvement of heat dissipation. When the content of the filler is 100% by mass of the composite material, 0.2% by mass or more, further 0.3% by mass or more, and particularly 0.5% by mass or more, it is easy to obtain a heat dissipation improvement effect, 20% by mass or less, When the content is 15% by mass or less, particularly 10% by mass or less, a decrease in the ratio of magnetic powder or resin can be suppressed. When the filler is finer than the magnetic powder, it is easy to interpose between the magnetic particles, and it is easy to suppress a decrease in the proportion of the magnetic powder due to the inclusion of the filler.

  Here, a coating powder having an insulating coating on the surface of particles made of an iron-based material (pure iron) having an average particle diameter of 75 μm or less is used as the magnetic powder of the composite material, and the content of the magnetic powder in the composite material is 40%. Volume%. Further, only the millable silicone rubber is used as the resin as the binder of the composite material. The composite material is obtained by blending magnetic powder and millable silicone rubber (including peroxide vulcanizing agent) before curing at a volume ratio of 40:60 and kneading. The composite material was cured by heating at 180 ° C. for 20 minutes and finally subjected to heat treatment. The heat treatment conditions were a heating temperature of 180 ° C. and a holding time of 2 hours.

  The outer core portion 32 is not particularly limited as long as a closed magnetic path can be formed. As described above, in the form in which the coil molded body 20 is covered with the composite material, the coil 2 (coil molded body 20) can be protected from the external environment and mechanical stress by the composite material (outer core portion 32). In addition, a part of the coil molded body 20 is exposed from the connecting core portion 32c, and heat can be easily transferred from the exposed surface to the heat radiating target, thereby improving heat dissipation.

(Magnetic properties)
As described above, the magnetic core 3 is partially made of different materials and has different magnetic characteristics. Specifically, the inner core portion 31 has a higher saturation magnetic flux density than the outer core portion 32, and the outer core portion 32 has a lower relative permeability than the inner core portion 31. More specifically, the inner core portion 31 has a saturation magnetic flux density of 1.0 T or more, more preferably 1.2 times or more of the outer core portion 32, a relative permeability of 50 to 500, and the outer core portion 32 has a saturation magnetic flux density. : 0.6 T or more, less than the saturation magnetic flux density of the inner core portion 31, relative permeability: 5 or more and 50 or less, and the relative permeability of the entire magnetic core 3 composed of the inner core portion 31 and the outer core portion 32 is 10 or more and 50 or less desirable. When obtaining a constant magnetic flux, the higher the absolute value of the saturation magnetic flux density of the inner core part, and the smaller the saturation magnetic flux density of the inner core part relative to the outer core part, the smaller the cross-sectional area of the inner core part. Easy to do. Therefore, the form with a high saturation magnetic flux density of the inner core portion contributes to the downsizing of the reactor because the cross-sectional area of the inner core portion can be reduced when the same saturation magnetic flux density as the magnetic core is obtained. . The saturation magnetic flux density of the inner core portion 31 is preferably 1.8 T or more, more preferably 2 T or more, more preferably 1.5 times or more, and more preferably 1.8 times or more of the saturation magnetic flux density of the outer core portion 32, and no upper limit is provided. If a laminated body of electromagnetic steel sheets typified by silicon steel sheets is used instead of the green compact, the saturation magnetic flux density of the inner core portion can be further increased. On the other hand, if the relative magnetic permeability of the outer core portion 32 is lower than that of the inner core portion 31, magnetic flux can be easily passed through the inner core portion 31. By the way, if the relative magnetic permeability of the outer core portion 32 is made higher than that of the inner core portion 31, the leakage magnetic flux to the outside can be easily reduced.

  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. 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 10000 (Oe) is applied to the test piece with an electromagnet and sufficiently magnetically saturated.

[Case]
The reactor 1a may include a case, and a combination of the coil 2 and the magnetic core 3 may be housed in the case. The shape and size of the case may be appropriately set according to, for example, the above arrangement form. The case has a function of protecting stored items (such as the coil 2 and the magnetic core 3) from the external environment and mechanical stress, and can also be used as a heat dissipation path. Therefore, a material having excellent thermal conductivity, preferably a material having higher thermal conductivity than magnetic powder such as iron, for example, a metal such as aluminum, aluminum alloy, magnesium, magnesium alloy can be suitably used as the case material. Aluminum, magnesium, and their alloys are lightweight, which contributes to reducing the weight of the reactor. Further, since aluminum, magnesium, and alloys thereof are nonmagnetic materials and conductive materials, leakage magnetic fluxes to the outside of the case can be effectively suppressed. When made of metal, the case can be easily manufactured by casting, cutting, plastic working, or the like. In addition, the case can be made of resin. When the case is made of resin, for example, polybutylene terephthalate (PBT) resin, urethane resin, PPS resin, acrylic-butadiene-styrene (ABS) resin, or the like can be used. In this case, from the viewpoint of improving heat dissipation, a ceramic filler having excellent thermal conductivity such as alumina or silica may be mixed. By forming the case from resin, it can be manufactured at a low cost and at a low cost.

[Usage]
Reactor 1a having the above-described configuration is representative of applications in which energization conditions for coil 2 are, for example, maximum current (direct current): about 100A to 1000A, average voltage: about 100V to 1000V, operating frequency: about 5kHz to 100kHz In particular, it can be suitably used as a component of an in-vehicle power conversion device such as a hybrid vehicle or an electric vehicle.

[Reactor size]
If the reactor 1a and the vehicle component, reactor 1a in the case comprising a case, it is preferable capacity, including the case of 0.2 liters (200 cm ³⁾ to 0.8 liters (800 cm ³⁾ approximately. More specifically, in the case of a coil having a circular end face shape, the inner diameter: 20 mm to 80 mm, the number of turns: 30 to 70, and in the case of a cylindrical inner core, the diameter: 10 mm to 70 mm, the length (coil axis Length along the direction): 20 mm to 120 mm.

[effect]
Reactor 1a is composed of a composite material in which a part of magnetic core 3 (here, outer core portion 32) is a mixture of magnetic powder and resin, and uses a millable silicone rubber as a resin serving as a binder for the composite material. Yes. Since the resin of the composite material is a millable silicone rubber, the fluidity is low and the viscosity is low. Therefore, the magnetic powder is unlikely to settle after mixing the magnetic powder and the resin. A uniformly dispersed state can be maintained, and the manufacturability is high while realizing the inductance as designed. Also, since the resin in the composite material is rubber, it has elasticity and is soft, so the composite material can absorb vibration and reduce noise caused by vibration, and thermal expansion between the magnetic powder and the resin Even if the coefficient difference occurs, it is possible to suppress the occurrence of cracks in the composite material due to the deformation of the resin. Furthermore, if it is a millable silicone rubber, it has high heat resistance and hardly deteriorates even at high temperatures.

  Therefore, the reactor core component made of the reactor 1a and the above composite material has high manufacturability and can reduce noise due to vibration.

<< Embodiment 2 >>
With reference to FIGS. 4-6, the reactor which concerns on Embodiment 2 is demonstrated. The basic configuration of the reactor 1b according to the second embodiment is the same as that of the reactor 1a according to the first embodiment, and the differences will be mainly described below.

  As shown in FIG. 6, one end of the winding 2w is drawn out in the radial direction of the coil 2 on one end side of the coil 2 as shown in FIG. The other end is extended in parallel with the axial direction of the coil 2 and is bent so as to be drawn out in the radial direction of the coil 2. As in the first embodiment, the coil 2 is a coil molded body 20 whose surface is covered with the resin mold portion 21 and whose shape is maintained.

  As shown in FIGS. 4 and 5, the outer core portion 32 covers substantially all of the coil molded body 20. As shown in FIG. 5, the connecting core portion 32 c constituting the outer core portion 32 is formed by winding a composite material so as to cover the outer peripheral surface of the coil molded body 20. As in the first embodiment, the inner peripheral surface of the composite material is provided with irregularities according to the outer shape of the coil molded body 20 so that no gap is formed between the coil molded body 20 and the connecting core portion 32c. I have to.

  On the other hand, as shown in FIG. 5, the end core portion 32e has an inner core portion disposition groove 321 on the inner surface facing the end surface of the coil molded body 20 and the end surface 31e of the inner core portion 31, as shown in FIG. A coil arrangement groove 322 is formed. Further, on the inner surface of the end core portion 32e disposed on one end side of the coil molded body 20 (that is, the side on which both end portions of the winding 2w are pulled out), a drawing groove 324 for pulling out both end portions of the winding 2w. Is provided.

<< Embodiment 3 >>
A reactor according to the third embodiment will be described with reference to FIGS. The basic configuration of the reactor 1c according to the third embodiment is the same as that of the reactor 1a according to the first embodiment, and the differences will be mainly described below.

  The method of pulling out both ends of the winding 2w forming the coil 2 is different. As shown in FIG. 9, both ends of the winding 2w are pulled out from the turn portions in the radial direction of the coil 2 at both ends of the coil 2, respectively. ing. As in the first embodiment, the coil 2 is a coil molded body 20 whose surface is covered with the resin mold portion 21 and whose shape is maintained.

  As shown in FIGS. 7 and 8, the outer core portion 32 covers substantially all of the coil molded body 20. As shown in FIG. 8, the connecting core portion 32 c constituting the outer core portion 32 is formed by winding a composite material so as to cover the outer peripheral surface of the coil molded body 20. As in the first embodiment, the inner peripheral surface of the composite material is provided with irregularities according to the outer shape of the coil molded body 20 so that no gap is formed between the coil molded body 20 and the connecting core portion 32c. I have to.

  On the other hand, as shown in FIG. 8, the end core portion 32e has an inner core portion arrangement groove 321 on the inner surface facing the end surface of the coil molded body 20 and the end surface 31e of the inner core portion 31, as shown in FIG. A coil arrangement groove 322 is formed. In addition, on the inner surface of each end core portion 32e disposed on both ends of the coil molded body 20, a lead groove 324 for pulling out each end portion of the winding 2w is provided.

<< Embodiment 4 >>
In Embodiment 1 described above, the coil 2 is provided with the coil molded body 20 whose surface is covered with the resin mold portion 21, and the insulation between the coil 2 and the magnetic core 3 is enhanced by the resin mold portion 21. did. In addition, for example, by attaching an insulating tape to the outer surface (including the end surface) or inner peripheral surface of the coil 2, or covering the outer surface (including the end surface) or inner peripheral surface of the coil 2 with insulating paper or an insulating sheet. The effect of improving the above-described insulation can be obtained. Or it can be set as the form which has arrange | positioned the cylindrical insulator to the outer periphery of the inner core part 31, and the outer periphery of the coil 2. FIG. As a constituent material of the insulator, an insulating resin such as a PPS resin, a liquid crystal polymer (LCP), or a polytetrafluoroethylene (PTFE) resin can be suitably used. If this insulator is a split piece that can be divided in the radial direction of the inner core portion 31 or the coil 2, it can be easily arranged on the outer periphery of the inner core portion 31 or the outer periphery of the coil 2, and is excellent in assembling workability. It is preferable that the cylindrical body disposed on the outer periphery of the inner core portion 31 includes an annular flange that protrudes outward from the peripheral edges of both ends, so that the end surface of the coil 2 can be covered by this flange.

<< Embodiment 5 >>
In the first embodiment, the form in which the inner core portion 31 is configured by a green compact and the outer core portion 32 is configured by a composite material has been described. In addition, the inner core portion can also be formed of a composite material in which magnetic powder and resin (millable silicone rubber) are mixed. That is, the whole magnetic core can be made of the composite material. In this case, the inner core portion and the outer core portion can be made of the same composite material. The content of the magnetic powder of the composite material constituting each core part is 30 volume% or more and 75 volume% or less, the saturation magnetic flux density of each core part is 0.6 T or more, preferably 1.0 T or more, and the relative permeability is 5 Or more, 50 or less, preferably 10 or more and 35 or less, more preferably 20 or more and 30 or less. For example, the relative permeability of the entire magnetic core is 5 or more and 50 or less. In this structure, you may form both an inner core part and an outer core part integrally using a shaping | molding die. For example, a coil molded body having no inner core portion, that is, a coil molded body including a coil and a resin mold portion and having a hollow hole in which the inner core portion is disposed is prepared. And after arrange | positioning this coil molded object to the predetermined position of a shaping | molding die, a composite material is filled into a shaping | molding die and it is in the hollow hole of a coil molded object, and the outer side (space between a coil molded object and a case). Pour and cure the composite material. Thus, the magnetic core which consists of a composite material with which the inner core part and the outer core part were united is obtained by shape | molding an inner core part and an outer core part integrally using a shaping | molding die. When the inner core portion and the outer core portion are integrally formed, it is not necessary to separately form the inner core portion and the outer core portion, and the joining operation between the inner core portion and the outer core portion can be omitted. Or it is good also as a molded object of the composite material which separately shape | molded the inner core part and the outer core part in the respectively predetermined shape. For example, an inner core portion made of a composite material molded body formed into a predetermined shape is prepared, and the inner core portion is arranged inside the coil to produce an integrated coil molded body. And this coil molded object is arrange | positioned in the predetermined position of a shaping | molding die, a composite material is filled into a shaping | molding die, and the outer core part which consists of composite materials is shape | molded. Alternatively, an outer core portion made of a molded body of a composite material molded into a predetermined shape is produced, and the outer core portion is arranged outside the coil molded body so as to form a closed magnetic path between the inner core portion and the outer core portion. And you may comprise a magnetic core. Thus, if the inner core portion and the outer core portion are formed of the same composite material, the core portions can be formed of the same composite material even if the core portions are formed separately. When the reactor includes a case, the case may be used for the mold.

  In the above example, the case where a coil molded body is used has been described as an example. However, it is possible to use a coil molded body that does not have a coil molded body, such as using a coil as it is. In this case, for example, as described in the fourth embodiment, an insulating tape is attached to the outer surface (including the end surface) or the inner peripheral surface of the coil, or the outer surface (including the end surface) or the inner peripheral surface of the coil is insulated paper or the like. If it is set as the form covered with the insulating sheet, the insulation between a coil and a magnetic core (an inner core part and an outer core part) can be improved. Alternatively, the insulator may be disposed on the contact portion between the coil and the magnetic core, specifically, on the inner peripheral surface of the coil or the outer surface (outer periphery or end surface) of the inner core portion, or on the outer surface (including the end surface) of the coil. Good.

  Further, the inner core portion and the outer core portion can be composed of composite materials having different magnetic powder materials and contents. In this configuration, for example, when the material of the magnetic powder is the same, the saturation magnetic flux density and the relative magnetic permeability can be adjusted by changing the content of the magnetic powder, and a composite material having desired characteristics can be easily obtained. There is also an advantage. As a specific form, the inner core portion and the outer core portion are made of composite materials having different magnetic powder materials and contents, and the inner core portion has a high saturation magnetic flux density as in the first embodiment, and the outer core portion It is mentioned that it is set as the form with low relative magnetic permeability. Alternatively, the reverse configuration, that is, a configuration in which the relative permeability of the inner core portion is low and the saturation magnetic flux density of the outer core portion is high can be mentioned. Increasing the blending amount of the magnetic powder in the composite material makes it easy to obtain a composite material having a high saturation magnetic flux density and a high relative magnetic permeability, and reducing the blending amount reduces the composite material having a low saturation magnetic flux density and a low relative magnetic permeability. Is easy to obtain. Depending on the raw material having a desired composition, for example, a columnar or block-shaped core component made of a molded body of a composite material can be separately prepared, and this core component can be used for the inner core portion and the outer core portion. Each of the composite materials constituting the inner core portion and the outer core portion has a magnetic powder content of 30 vol% or more and 75 vol% or less, and the saturation magnetic flux density of each core portion is 0.6 T or more, preferably 1.0 T or more. The relative magnetic permeability is 5 or more and 50 or less, preferably 10 or more and 35 or less, and more preferably 20 or more and 30 or less. For example, the relative permeability of the entire magnetic core is 5 or more and 50 or less.

  In the first embodiment, the connection core portion 32c and the end core portion 32e are described as separate members. However, the connection core portion and the end core portion are integrally formed of the same composite material. Alternatively, it may be composed of composite materials having different magnetic powder materials and contents. Furthermore, the end core portion may be formed of a compacted body, or may be formed of a conventional composite material in which magnetic powder and a resin (such as an epoxy resin) are mixed.

  By the way, when a part of the magnetic core (for example, the inner core part) is made of a magnetic body having a high relative permeability such as a compacted body or a laminate of electromagnetic steel sheets, the inductance is adjusted between the adjacent core pieces or A gap material made of a material having a lower relative permeability than the magnetic body (typically a nonmagnetic material such as alumina) may be interposed between the core portions. As the gap material, a magnetic material having a relative magnetic permeability of 1.05 or more and 2 or less can be used in addition to a nonmagnetic material. An example of such a gap material made of a magnetic material is a mixture containing a non-magnetic material such as PPS resin and a magnetic material such as iron powder. When the magnetic core includes a gap material, the relative magnetic permeability of the entire magnetic core is the relative permeability including the gap material.

Embodiment 6
In the first embodiment, the form in which one cylindrical coil 2 is provided (that is, the coil 2 has one coil element) has been described. In addition, it can be set as the form which provides a pair of coil element formed by winding a coil | winding helically. A pair of coil elements are arranged side by side (parallel arrangement) so that the axes of the respective elements are parallel, and are connected by a connecting portion formed by folding back a part of the winding. Each coil element is formed by separate windings, one end of the windings forming both coil elements are joined together by welding such as TIG welding, crimping, soldering, etc., a connecting member with one end prepared separately It can also be set as the form connected via.

  With reference to FIG. 10, FIG. 11, the reactor which concerns on Embodiment 6 is demonstrated. The reactor 1A of the sixth embodiment is different from the reactor 1a of the first embodiment in the configuration of the coil 2 and the magnetic core 3. Below, in order to simplify description, it demonstrates centering on difference.

  As shown in FIG. 11, the coil 2 includes a pair of coil elements 2a and 2b, and is arranged side by side (in parallel) so that the axes of the coil elements are parallel to each other. This coil 2 (coil elements 2a, 2b) is formed by one continuous winding 2w. Specifically, after one coil element 2a is formed from one end side to the other end side, the other end On the side, the winding 2w is bent in a U shape and folded, and the other coil element 2b is formed from the other end side toward the one end side. The winding directions of both coil elements 2a and 2b are the same. Both coil elements 2a and 2b are electrically connected in series. Then, both end portions of the winding 2w are drawn out from the one end side of the coil 2 (coil elements 2a, 2b) in the radial direction of the coil 2 (upward in FIG. 11). The end surfaces of the coil elements 2a and 2b are rectangular with rounded corners. As described above, the end surfaces of the coil elements 2a and 2b can be selected as appropriate, such as a circular shape or a racetrack shape. Inner core portions 31 are disposed inside the coil elements 2a and 2b, respectively.

  Similarly to the first embodiment, the coil 2 has a coil molded body 20 whose surface is covered with the resin mold portion 21, and the coil 2 and the inner core portion 31 are integrally molded by the resin mold portion 21. Yes. Of course, the coil 2 may have a form in which the surface thereof is not a coil molded body covered with a resin mold portion. In this case, for example, as described in the fourth embodiment, an insulating tape is attached to the outer surface (including the end surface) or the inner peripheral surface of the coil 2, or the outer surface (including the end surface) or the inner peripheral surface of the coil 2 is insulated. In the form of being covered with paper or an insulating sheet, the insulation between the coil 2 and the magnetic core 3 (an inner core portion 31 and an outer core portion 32 described later) can be enhanced. Alternatively, an insulator is provided on a contact portion between the coil 2 and the magnetic core 3, specifically, on the inner peripheral surface of the coil 2 or the outer surface (outer periphery or end surface) of the inner core portion 31 or on the outer surface (including the end surface) of the coil 2. It is good also as the arrangement | positioning form.

  The inner core portion 31 is a prismatic body that is disposed inside each of the coil elements 2a and 2b and extends along the inner peripheral shape of each of the coil elements 2a and 2b. In this example, the inner core portion 31 is formed of a composite material molded body in which magnetic powder and a resin (millable silicone rubber) are mixed. On the other hand, as shown in FIGS. 10 and 11, the outer core portion 32 has a block shape and is disposed at both ends of the inner core portions 31 so as to sandwich the inner core portions 31. In this example, the outer core portion 32 is formed of a composite material molded body, like the inner core portion 31. The outer core portion 32 is connected to the end faces 31e of the inner core portions 31, whereby the inner core portion 31 and the outer core portion 32 form an annular magnetic core 3, and the magnetic core 3 has a closed magnetic path. It is formed. The inner core portion 31 and the outer core portion 32 are formed of the above-mentioned composite material, and since they themselves have adhesiveness, it is possible to connect the two by attaching the outer core portion 32 to the inner core portion 31. it can. The inner core portion 31 and the outer core portion 32 may be connected by, for example, an adhesive.

  In the example described above, the entire magnetic core is composed of a composite material in which magnetic powder and resin (millable silicone rubber) are mixed. And as demonstrated in Embodiment 5, an inner core part and an outer core part can be comprised with the composite material from which the material and content of magnetic powder are the same or different. In this case, both the inner core portion and the outer core portion may be integrally formed using a molding die, or as a composite material molded body in which the inner core portion and the outer core portion are separately molded into predetermined shapes, respectively. Also good. In the former case, for example, after a coil molded body having no inner core portion is arranged at a predetermined position of the molding die, the composite material is filled into the molding die, and the inner core portion and the outer core portion are integrated. A magnetic core can be formed by molding. In the latter case, for example, after a coil molded body in which an inner core portion made of a molded body of a composite material is arranged and integrated inside the coil is disposed at a predetermined position of the molding die, the composite is the same as or different from the inner core portion. For example, a magnetic core can be formed by filling a mold with a material and molding an outer core portion made of a composite material. Or you may comprise a magnetic core by arrange | positioning the outer core part which consists of a molded object of the same or different composite material as an inner core part in a predetermined position so that a closed magnetic circuit may be formed. When the reactor includes a case, the case may be used for the mold.

  Here, when the inner core portion and the outer core portion are composed of the above composite material, as described in the fifth embodiment, the composite material constituting each core portion has a magnetic powder content of 30% by volume. The saturation magnetic flux density of each core part is 0.6 T or more, preferably 1.0 T or more, and the relative magnetic permeability is 5 or more and 50 or less, preferably 10 or more and 35 or less, more preferably 20 or more and 30 or less. Can be mentioned. For example, the relative permeability of the entire magnetic core is 5 or more and 50 or less. In addition, when the inner core portion and the outer core portion are composed of composite materials having different magnetic powder materials and contents, the saturation magnetic flux density of the inner core portion is high and the relative permeability of the outer core portion is low, Alternatively, the reverse configuration, that is, a configuration in which the relative permeability of the inner core portion is low and the saturation magnetic flux density of the outer core portion is high can be mentioned. Increasing the blending amount of the magnetic powder in the composite material makes it easy to obtain a composite material having a high saturation magnetic flux density and a high relative magnetic permeability, and reducing the blending amount reduces the composite material having a low saturation magnetic flux density and a low relative magnetic permeability. Is easy to obtain. For example, when the magnetic powder is made of the same material, the saturation magnetic flux density and the relative magnetic permeability can be adjusted by changing the content of the magnetic powder, and a composite material having desired characteristics can be easily obtained.

  In the reactor 1A described above, one of the inner core portion 31 and the outer core portion 32 may be formed of a powder compact, or may be formed of a composite material in which magnetic powder and a resin (such as an epoxy resin) are mixed. May be. When a part of the magnetic core (for example, the inner core part) is made of a magnetic material having a high relative permeability such as a compacted body or a laminate of electromagnetic steel sheets, as described in the fifth embodiment, they are adjacent to each other. A gap material may be interposed between the core pieces or between the core portions.

<< Embodiment 7 >>
Next, an embodiment of a reactor including a case will be described with reference to FIG. Embodiment 7 shown in FIG. 12 is a form including a case 4 in which the assembly of the coil 2 and the magnetic core 3 is accommodated in the reactor 1A of Embodiment 6 described above. When the case 4 is provided in this way, as shown in FIG. 12, the case 4 is filled with the sealing resin 6, and the assembly of the coil 2 and the magnetic core 3 is sealed with the sealing resin 6. Also good. Thus, the coil 2 (coil molded body 20) and the magnetic core 3 (outer core portion 32) can be covered with the sealing resin 6, and these members can be protected from the external environment and mechanical stress. As the sealing resin 6, for example, an epoxy resin, a polyurethane resin, a silicone resin, an unsaturated polyester resin, a PPS resin, or the like can be suitably used. From the viewpoint of improving heat dissipation, the sealing resin 6 may be mixed with a high ceramic filler such as alumina or silica that has excellent thermal conductivity.

[Converters, power converters]
The reactor of Embodiments 1-7 according to the present invention described above can be used, for example, as a component part of a converter mounted on a vehicle or the like, or a component part of a power conversion device including this converter.

  For example, a vehicle 1200 such as a hybrid vehicle or an electric vehicle is 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. A motor (load) 1220 used. 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, the vehicle 1200 includes an engine in addition to the motor 1220. In addition, in FIG. 13, although an inlet is shown as a charge location of the vehicle 1200, the form which provides a plug may be sufficient.

  The power conversion device 1100 includes a converter 1110 connected to the main battery 1210 and an inverter 1120 connected to the 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 feeds power to inverter 1120 when vehicle 1200 is traveling. In addition, converter 1110 steps down a DC voltage (input voltage) output from motor 1220 via inverter 1120 to a DC voltage suitable for main battery 1210 during regeneration, and charges main battery 1210. 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 power to the motor 1220. 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. 14, 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. Conversion (here, step-up / step-down) is performed. For the switching element 1111, a power device such as an FET or an 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 tends to prevent the change of the current to flow through the circuit. As this reactor L, the reactor of the said Embodiments 1-7 is provided. By including the reactor 1a capable of reducing noise caused by vibration, the power conversion device 1100 and the converter 1110 are excellent in quietness.

  Vehicle 1200 is connected to converter 1110, power supply converter 1150 connected to main battery 1210, sub-battery 1230 as a power source for auxiliary devices 1240, and main battery 1210. Auxiliary power converter 1160 for converting high voltage to 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 converters 1150 for power feeding devices 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 first to seventh embodiments, and a reactor whose size and shape are appropriately changed can be used. Moreover, the reactor of the said Embodiments 1-7 can also be utilized for the converter which performs conversion of input electric power, Comprising: The converter which performs only a pressure | voltage rise, or the converter which performs only a pressure | voltage fall.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention. For example, it is possible to appropriately change the composition of the composite material (the content of magnetic powder and resin (millable silicone rubber), etc.), the material and particle size of the magnetic powder, and the shape and size of the coil and magnetic core.

(Appendix 1)
A composite material in which magnetic powder and a resin are mixed, wherein the resin is a millable silicone rubber.

  As described in the description of the present invention so far, this composite material can be used as a magnetic member (magnetic body) included in various magnetic components in addition to being used for a magnetic core included in a reactor. In this composite material, as described above, since the resin is a millable silicone rubber, it is difficult for the magnetic powder to settle after the magnetic powder and the resin are kneaded, and the magnetic powder is uniformly dispersed in the composite material. Can be maintained. Therefore, it is easy to realize the intended magnetic characteristics and the productivity is high. In addition, since the resin in the composite material is rubber, it has elasticity and is soft even after being cured. Therefore, even if the composite material absorbs vibration, noise due to vibration is reduced, or even if a thermal expansion coefficient difference occurs between the magnetic powder and the resin, the composite material will be cracked due to deformation of the resin. Can be suppressed.

(Appendix 2)
A magnetic component comprising a magnetic member, wherein at least a part of the magnetic member is made of the composite material according to appendix 1.

(Appendix 3)
A magnetic component comprising a coil and a magnetic member on which the coil is disposed, wherein at least a part of the magnetic member is made of the composite material according to appendix 1.

  In addition to the reactor, examples of the magnetic component include a choke coil, a transformer, a magnetic sensor, a current sensor, and an electromagnetic noise countermeasure component (for example, an electromagnetic wave absorbing sheet). As specific examples, the composite material molded body may be used as a part of a magnetic core of a choke coil, a transformer, a magnetic sensor, or a current sensor, or a composite material molded into a sheet shape may be used for an electromagnetic wave absorbing sheet. It is done. In the magnetic component, since at least a part of the magnetic member is composed of the composite material, and the resin of the composite material is a millable silicone rubber, as described above, it is easy to realize the intended magnetic characteristics and manufacture. High nature. In addition, if the resin of the composite material is a millable silicone rubber, the composite material can absorb vibrations to reduce noise due to vibrations, or even if a difference in thermal expansion coefficient occurs between the magnetic powder and the resin. By deforming, it is possible to suppress the occurrence of cracks in the composite material. In particular, it is preferable that all of the magnetic members are made of the composite material, which can improve the productivity and suppress the occurrence of cracks in the magnetic members.

  The reactor of the present invention can be used for components of power conversion devices such as DC-DC converters and air conditioner converters mounted on vehicles such as hybrid vehicles, plug-in hybrid vehicles, electric vehicles, and fuel cell vehicles. The core part for reactors of this invention can be utilized for the magnetic core provided in a reactor.

1a, 1b, 1c, 1A reactor
2 coil 2w winding
20 Coil molded body 21 Resin mold part
2a, 2b coil element
3 Magnetic core
31 Inner core 31e End face
32 Outer core part 32c Connecting core part 32e End core part
321 Inner core placement groove 322 Coil placement groove
323 Drawer hole 324 Drawer groove
4 cases
6 Sealing resin
1100 Power converter 1110 Converter 1120 Inverter
1200 vehicles
1111 Switching element 1112 Drive circuit L Reactor
1150 Power supply converter 1160 Auxiliary power converter
1210 Main battery 1220 Motor
1230 Sub-battery 1240 Auxiliary 1250 Wheel

Claims (9)

A cylindrical coil;
A reactor comprising a magnetic core disposed inside and outside the coil to form a closed magnetic circuit,
At least a part of the magnetic core is composed of a composite material obtained by mixing magnetic powder and resin,
The reactor is a millable silicone rubber.   The reactor according to claim 1, wherein a content of the magnetic powder in the composite material is 30% by volume or more and 75% by volume or less.   The reactor according to claim 1, wherein the coil includes a pair of coil elements arranged side by side.   The reactor as described in any one of Claims 1-3 in which at least one part of the location arrange | positioned outside the said coil among the said magnetic core is comprised with the said composite material.   The reactor as described in any one of Claims 1-4 by which the location arrange | positioned inside the said coil among the said magnetic core is comprised with the compacting body.   The reactor according to any one of claims 1 to 3, wherein the entire magnetic core is made of the composite material.   The converter which provides the reactor as described in any one of Claims 1-6.   A power converter comprising the converter according to claim 7. A core component for a reactor that constitutes a magnetic core included in a reactor,
A core part for a reactor which is made of a composite material in which magnetic powder and a resin are mixed, and the resin is a millable silicone rubber.

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