WO2017029914A1 - Reactor - Google Patents

Abstract

A reactor comprises: a magnetic core (20); a coil (30); a first cooling member (40, 60); a second cooling member (41, 61); a first sealing resin portion (50); and a second sealing resin portion (51). The first sealing resin portion and the second sealing resin portion, by being filled in a gap between a heat radiating surface of the first cooling member and the magnetic core and a gap between a heat radiating surface of the second cooling member and the magnetic core, are formed to expose side surfaces (20c, 20d) of the magnetic core while sealing a lower surface (20b) of the magnetic core and an upper surface (20a) of the magnetic core. A cross sectional shape of the magnetic core in a plane orthogonal to the flow of magnetic fluxes produced upon energization of the coil is a flattened shape of which a dimension in a perpendicular direction with respect to the same direction as a direction in which the first cooling member and the second cooling member are arranged is greater than a dimension in the same dimension.

Description

Reactor Cross-reference of related applications

This application is based on Japanese Application No. 2015-161178 filed on August 18, 2015 and Japanese Application No. 2015-161179 filed on August 18, 2015. Incorporate.

This disclosure relates to a reactor in which a wound coil is wound around a magnetic core.

Conventionally, in a reactor mounted on a hybrid vehicle or the like, the copper loss of the coil and the iron loss of the magnetic core occur, and thus the reactor generates heat. Since the output of the hybrid vehicle is large, the reactor heat is also increased. For this reason, a heat sink is provided on the lower surface of the reactor, and the reactor is cooled by releasing heat from the heat sink via the bobbin and the sealing resin.

However, due to the difference in linear expansion coefficient between the bobbin and the core, the bobbin or the like is easily cracked by heat shock, and the occurrence of this crack causes insulation failure, which causes the reactor to burn out.

As a solution to this problem, a bobbin-less reactor is proposed in Patent Document 1. By forming the reactor in a bobbinless manner as described above, the difference in linear expansion coefficient is reduced, the generation of cracks is suppressed, and it becomes possible to suppress the insulation failure and the reactor burnout resulting therefrom.

Specifically, a gap between the coil and the magnetic core is sealed by filling a resin sealing material in which a filler is blended in a state where the magnetic core and the coil are arranged in a housing serving as a housing. . The resin sealing material has a performance of a thermal conductivity of 0.7 to 4 W / mK, and has a low viscosity so that the gap between the coil and the magnetic core is sealed. . The magnetic core is composed of two U-shaped cores and a gap member. Both ends of the two U-shaped cores face each other while being inserted into the coil, and are connected via the gap member to form an annular shape. It is said. Then, while positioning the annular magnetic core by pressing it against the inner wall surface of the housing with a leaf spring from the outside in the radial direction, the coil is pressed and positioned from above, and the resin sealing material is filled in this state. Thus, resin sealing is performed.

However, since the magnetic core is resin-sealed in a state where pressure is applied by the leaf spring, the characteristics of the magnetic core are deteriorated, that is, the loss is increased and the magnetic permeability is decreased. In addition, since the coil and the magnetic core are all covered with a resin sealing material, the magnetic core characteristics are also deteriorated due to the resin sealing.

In addition, it is known that the magnetic core decreases the permeability and increases the loss when stress is applied due to the magnetostrictive effect. In the structure of Patent Document 1, the following (1) to (3) can be cited as factors for applying stress to the magnetic core. That is, (1) pressure is applied from the peripheral member, (2) the resin sealed around the magnetic core is cured and shrunk, and stress is applied to the magnetic core, and (3) magnetic flux The stress is applied by interfering with the sealed resin due to the expansion of the magnetic core to which is applied. Fixing the magnetic core with a leaf spring generates the factor (1), and sealing the entire magnetic core or coil with a resin sealing material generates the factors (2) and (3). It will be.

JP 2009-94328 A

This disclosure is intended to provide a reactor that can perform good heat dissipation while suppressing deterioration of characteristics of a magnetic core due to resin sealing or pressurization.

A reactor according to an aspect of the present disclosure includes a magnetic core, a coil wound around the magnetic core, a first cooling member and a second cooling member, a first sealing resin portion, and a second sealing resin portion. Have. The first cooling member and the second cooling member are disposed on both sides of the magnetic core and the coil, include heat radiation surfaces on which the magnetic core and the coil are disposed, and perform heat radiation of the magnetic core and the coil. The first sealing resin portion and the second sealing resin portion are filled between the heat dissipation surface of the first cooling member and the magnetic core, thereby sealing the lower surface on the heat dissipation surface side of the magnetic core. In addition, by filling the space between the heat dissipation surface of the second cooling member and the magnetic core, both sides of the magnetic core connected to the heat dissipation surface are sealed while sealing the upper surface on the heat dissipation surface side of the magnetic core. It is formed to be exposed. The magnetic core has a cross-sectional shape in a plane perpendicular to the flow of magnetic flux generated when the coil is energized, with respect to the direction in the same direction as the direction in which the first cooling member and the second cooling member are arranged. It is a flat shape with a large vertical dimension.

Thus, while the first sealing resin portion and the second resin sealing portion are in contact with the lower surface or the upper surface of the magnetic core, the magnetic core is exposed from the sealing resin portion on both side surfaces. For this reason, it becomes possible to keep the area | region where a stress is applied to a magnetic core by hardening shrinkage of a 1st sealing resin part and a 2nd resin sealing part to the minimum. In addition, it is possible to minimize the application of stress by interfering with the first sealing resin portion and the second resin sealing portion due to the magnetostriction of the magnetic core itself. Further, the cross-sectional shape of the magnetic core is flattened to increase the cooling area with respect to the volume of the magnetic core. Thereby, it becomes possible to ensure heat dissipation.

Further, according to such a configuration, it is possible to make a structure in which there is almost no pressure from the peripheral member against the magnetic core, for example, a pressing by a leaf spring from the radially outer side of the magnetic core, and from the sealing resin portion accompanying the thermal deformation Can also be suppressed. Furthermore, even if the magnetic core to which the magnetic flux is applied is expanded when the reactor is used, the contact portions with the first sealing resin portion and the second resin sealing portion are almost only the lower surface and the upper surface on the heat radiation surface side of the magnetic core. Therefore, the stress applied from the first sealing resin portion and the second resin sealing portion due to the magnetostriction of the magnetic core itself can be suppressed. Therefore, it is possible to suppress the deterioration of the characteristics of the magnetic core due to resin sealing or pressurization, that is, increase in loss or decrease in magnetic permeability.

A reactor according to another aspect of the present disclosure includes a magnetic core, a coil wound around the magnetic core, a cooling member, a core support portion, a coil support portion, and a sealing resin portion. The cooling member includes a heat radiating surface on which the magnetic core and the coil are disposed, and radiates heat from the magnetic core and the coil. The core support part is provided so as to protrude from the heat dissipation surface and supports the magnetic core. The coil support portion is provided so as to protrude from the heat dissipation surface and supports the coil. The sealing resin part is filled between the magnetic core from the heat dissipation surface in a state where the magnetic core is supported by the core support part and the coil is supported by the coil support part. The magnetic core is formed so as to expose the surface opposite to the heat radiating surface while sealing the surface side surface.

Since the reactor configured in this manner is filled with the sealing resin portion between the magnetic core and coil and the cooling member, heat from the magnetic core and coil can be efficiently transmitted to the cooling member. In addition, while sealing the heat dissipation surface side of the magnetic core with the sealing resin portion, the surface opposite to the heat dissipation surface is not covered so that the magnetic core is exposed from the sealing resin portion. Yes. For this reason, it becomes possible to keep the area | region where a stress is applied to a magnetic core by hardening shrinkage | contraction of a sealing resin part to the minimum. In addition, it is possible to minimize the application of stress due to interference with the sealing resin portion due to the magnetostriction of the magnetic core itself.

Further, according to such a configuration, there is no pressurization from the peripheral member against the magnetic core, for example, pressing by a leaf spring, and pressurization from the sealing resin portion accompanying thermal deformation can be suppressed. Furthermore, even if the magnetic core to which magnetic flux is applied is expanded when the reactor is used, the contact portion with the sealing resin portion is almost only the surface on the heat radiating surface side of the magnetic core. This can suppress the stress applied from the sealing resin portion. Therefore, it is possible to suppress the deterioration of the characteristics of the magnetic core due to resin sealing or pressurization, that is, increase in loss or decrease in magnetic permeability.

The above and other objects, configurations, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the following drawings. In the drawing
FIG. 1 is a partial cross-sectional top view of a reactor according to the first embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the reactor along the line II-II in FIG. FIG. 3 is a cross-sectional view of the reactor along the line III-III in FIG. FIG. 4 is an exploded perspective view of the reactor shown in FIG. FIG. 5 is a diagram showing specifications assuming a case where the reactor is applied as a reactor for a boost converter for a vehicle. FIG. 6 is a diagram showing the relationship between the thermal resistance and heat generation temperature corresponding to the dimension setting of each part when the magnetic core has a cubic shape and when it has a flat shape. FIG. 7 is a cross-sectional view of a reactor according to the second embodiment of the present disclosure. FIG. 8 is a cross-sectional view of a reactor according to the third embodiment of the present disclosure. FIG. 9A is a cross-sectional view showing the stress applied from the sealing resin portion during curing shrinkage when the bottom surface of the housing is flat. FIG. 9B is a cross-sectional view showing a state in which the housing is damaged by the stress shown in FIG. 9A. FIG. 10 is a partial cross-sectional top view of the reactor according to the fourth embodiment of the present disclosure. FIG. 11 is a cross-sectional view of the reactor along the line XI-XI in FIG. 12 is an exploded perspective view of the reactor shown in FIG. FIG. 13 is a diagram showing specifications assuming a case where the reactor is applied as a reactor for a boost converter for a vehicle. FIG. 14 is a diagram showing the relationship between the thermal resistance and the heat generation temperature corresponding to the dimension setting of each part when the magnetic core has a cubic shape and when it has a flat shape.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present disclosure will be described with reference to FIGS. As shown in FIGS. 1 to 4, the reactor 10 of the present embodiment has a configuration including a magnetic core 20, a coil 30, housings 40 and 41, sealing resin portions 50 and 51, coolers 60 and 61, and the like. Has been. The reactor 10 is applied to generate a high output, such as a boost converter reactor mounted on an electric vehicle, a hybrid vehicle, or the like.

The magnetic core 20 is made of a soft magnetic material used as a core material, such as an iron-based alloy or an amorphous metal (eg, an iron-based amorphous material), and has a thermal conductivity of 1 to 50 W / mK, for example. In this embodiment, as shown in FIG. 1, the magnetic core 20 has a rectangular frame shape with two sets of two sides facing each other, but any other shape can be used as long as the magnetic flux flows. Also good. For example, the upper surface shape may be a circular frame shape. Further, the magnetic core 20 does not have to be a single member, and a plurality of divided cores may be integrated, or may be arranged so as to be in contact with each other.

Further, as shown in FIG. 2, the magnetic core 20 has a quadrangular cross-sectional shape in a direction perpendicular to the flow of magnetic flux generated when the coil 30 is energized. More specifically, the magnetic core 20 has a flat shape in which the dimension in the width direction, which is a dimension in the left-right direction on the paper surface, is larger than the dimension in the thickness direction, which is a dimension in the vertical direction on the paper surface. In other words, the magnetic core 20 has a flat shape in which the dimension in the direction perpendicular to the direction is larger than the dimension in the same direction as the direction in which the casings 40 and 41 and the coolers 60 and 61 are arranged. In the case of this embodiment, the cross-sectional shape of the magnetic core 20 is rectangular. And the upper surface 20a and the lower surface 20b which comprise a long side are made to oppose the bottom surfaces 40b and 41b which comprise the thermal radiation surface of the housing | casing 40 and 41 mentioned later. And each surface which connects between the upper surface 20a and the lower surface 20b, that is, the inner peripheral side surface 20c and the outer peripheral side surface 20d constituting the short side are oriented in a direction perpendicular to the bottom surfaces 40b and 41b of the casings 40 and 41. The magnetic core 20 is disposed on the casings 40 and 41.

The coil 30 is wound around the magnetic core 20 and is constituted by a conductor wire such as copper coated with an insulating film. As described above, in the present embodiment, the magnetic core 20 has a quadrangular frame shape, but the coil 30 is wound around each of two opposite sides of the magnetic core 20. The coil 30a wound around one side of the magnetic core 20 and the coil 30b wound around the other side are connected. In the case of this embodiment, the coil 30a and the coil 30b are connected via the connection part 30c in the downward position of the magnetic core 20, ie, the housing | casing 40 side. In addition, of the conductor wires constituting the coils 30a and 30b, the ends on the opposite side to the connecting portion 30c are drawn wirings 30aa and 30ba drawn at positions not covered with the sealing resin portions 50 and 51. . The coil 30 is electrically connected to an external circuit through the lead wires 30aa and 30ba, so that the reactor 10 can be energized.

The casings 40 and 41 are cases for housing the magnetic core 20 and the coil 30 and are made of a high material having a thermal conductivity of, for example, 50 W / mK or more, for example, aluminum. The casings 40 and 41 are disposed on one side and the other side of the magnetic core 20 and the coil 30, respectively, and the magnetic core 20 and the coil 30 are held between the casings 40 and 41. In the present embodiment, the casing 40 and the cooler 60 and the casing 41 and the cooler 61 are configured as separate bodies, but these constitute the first cooling member and the second cooling member, respectively. The 1st cooling member and the 2nd cooling member may be constituted by being united.

The casings 40 and 41 are constituted by bottomed members having recesses 40a and 41a for accommodating the magnetic core 20 and the coil 30 as shown in FIGS. 2 to 4, and as shown in FIG. In the case of this embodiment, the bottom surface member is a quadrangular bottomed member. Specifically, the casings 40 and 41 have side surfaces 40c and 41c in addition to the bottom surfaces 40b and 41b constituting the heat radiation surface, and the bottom surfaces 40b and 41b and the side surfaces 40c and 41c constitute the recesses 40a and 41a. Has been. Then, as shown in FIG. 1, the magnetic core 20 and the coil 30 are accommodated so as to be disposed within a range surrounded by the side surfaces 40c and 41c and so that at least a part of the recesses 40a and 41a enter in the depth direction. ing.

More specifically, the recesses 40a and 41a formed in the casings 40 and 41 are set to a depth at which the lower surface 20b of the magnetic core 20 is in close contact with sealing resin portions 50 and 51 described later. That is, when the magnetic core 20 and the coil 30 are housed in the housing 40, the end portions of the side surfaces 40c and 41c opposite to the bottom surfaces 40b and 41b are located farther from the bottom surfaces 40b and 41b than the bottom surface 20b of the magnetic core 20 is. The heights of the side surfaces 40c and 41c are set so as to reach.

The bottom surfaces 40b and 41b of the casings 40 and 41 are provided with core support portions 40d and 41d that support the magnetic core 20 and coil support portions 40e and 41e that support the coil 30, respectively. The core support portions 40d and 41d and the coil support portions 40e and 41e are configured by leaf springs or spacers disposed on the bottom surfaces 40b and 41b. As long as the magnetic core 20 and the coil 30 can be supported between the housings 40 and 41 without being displaced, the core support portions 40d and 41d and the coil support portions 40e and 41e may be configured by spacers. Further, when it is necessary to press the magnetic core 20 and the coil 30 in a direction in which the magnetic core 20 and the coil 30 are sandwiched in order to perform support without misalignment, the core support portions 40d and 41d and the coil support portions 40e and 41e are configured by leaf springs. Is preferred.

The core support portions 40d and 41d and the coil support portions 40e and 41e may be integrated with the casings 40 and 41, or may be configured as separate members. When the casings 40 and 41 are made of a conductive material, at least a part of the coil support portions 40e and 41e is made of an insulating material so that the casings 40 and 41 and the coil 30 can be insulated. Yes. As the insulating material, for example, resin or ceramics can be used.

Further, the shapes of the core support portions 40d and 41d and the coil support portions 40e and 41e are arbitrary, but a gap between the magnetic core 20 supported by these and the coil 30 is secured, and the housing 40, The dimensions are determined so that the insulation between 41 and the coil 30 is ensured.

The core support portions 40d and 41d and the coil support portions 40e and 41e are provided at a plurality of locations so that the magnetic core 20 can be supported with respect to the casings 40 and 41 in a state before resin sealing by the sealing resin portions 50 and 51. It is provided. The formation positions of the core support portions 40d and 41d and the coil support portions 40e and 41e may be anywhere as long as they can support the magnetic core 20 and the coil 30 without inclination.

The sealing resin parts 50 and 51 constitute the first resin sealing part and the second resin sealing part, and are binder resins containing a heat radiation filler. For example, alumina or the like is used as the heat dissipating filler, and epoxy resin or silicone resin is used as the resin material. The sealing resin portions 50 and 51 made of such a material have a thermal conductivity of 0.7 to 4 W / mK, for example, 3 W / mK.

The sealing resin portions 50 and 51 are filled in the recesses 40a and 41a formed in the casings 40 and 41 and cured. The sealing resin portions 50 and 51 are immersed in portions of the coil 30 that are located closer to the bottom surfaces 40 b and 41 b than the magnetic core 20. The sealing resin portion 50 is formed at least to a position where the lower surface 20b of the magnetic core 20 contacts. Further, the sealing resin portion 51 is formed at least up to a position where the upper surface 20a of the magnetic core 20 contacts. As the sealing resin portions 50 and 51, those having a low viscosity in a state before being cured are applied, and there is a gap between the magnetic core 20 and the coil 30 or between these and the housings 40 and 41. It can be filled without any problems.

However, the sealing resin portion 50 is in contact with the lower surface 20b of the magnetic core 20, but is not substantially covered except in the vicinity of the lower surface 20b, and the lower surface 20b of the lower surface 20b of the magnetic core 20 and both side surfaces 20c and 20d. It covers only the vicinity. The sealing resin portion 51 is also in contact with the upper surface 20a of the magnetic core 20, but is not substantially covered except in the vicinity of the upper surface 20a, and the vicinity of the upper surface 20a of the upper surface 20a and both side surfaces 20c and 20d of the magnetic core 20 Only covering. For this reason, both side surfaces 20 c and 20 d of the magnetic core 20 are exposed from the sealing resin portions 50 and 51. Considering the stress that the magnetic core 20 receives from the sealing resin portion 50, it is preferable that the sealing resin portions 50 and 51 are formed up to a position in contact with the lower surface 20 b of the magnetic core 20. However, in consideration of variations in the curing shrinkage of the resin, the cured sealing resin portions 50 and 51 may be separated from the lower surface 20b or the upper surface 20a. For this reason, it is preferable to form the sealing resin portion 50 to a position slightly closer to the upper surface 20a than the lower surface 20b, and it is preferable to form the sealing resin portion 51 to a position slightly closer to the lower surface 20b than the upper surface 20a. . Therefore, the sealing resin portions 50 and 51 are formed at the above positions.

The coolers 60 and 61 constitute part of the first cooling member and the second cooling member. In the case of the present embodiment, the connectivity is improved by being bonded to the bottom surfaces 40b and 41b of the casings 40 and 41 via the heat radiating gels 70 and 71 having a high thermal conductivity such as a silicone gel. . For example, in the case of silicone gel, the thermal conductivity is about 1 W / mK, and heat transfer from the casings 40 and 41 to the coolers 60 and 61 can be performed satisfactorily by applying thinly.

The coolers 60 and 61 may be air-cooled or water-cooled. In the case of the air-cooling type, the coolers 60 and 61 may be heat sinks composed of, for example, a simple high thermal conductor plate, or the back side opposite to the coil 30, the magnetic core 20, and the casings 40 and 41. A heat sink provided with heat radiating fins may be used. Moreover, the structure which comprises a refrigerant path inside the coolers 60 and 61, and makes a refrigerant | coolant flow in a refrigerant path may be sufficient.

As described above, the reactor 10 according to the present embodiment is configured. The reactor 10 configured as described above is manufactured as follows.

First, the magnetic core 20, the coil 30, and the casings 40 and 41 are prepared. The coil 30 is disposed around the magnetic core 20. For example, the magnetic core 20 is composed of two U-shaped cores and the like, and the tips of the two U-shaped cores are inserted into the coil 30 from opposite directions, whereby the coil 30 is wound around the magnetic core 20. A rotated structure can be constructed.

Then, the magnetic core 20 and the coil 30 are arranged in the recess 40a of the housing 40, and the resin material including the heat radiation filler is filled in the recess 40a in a state where they are pressed from above to the bottom surface 40b side of the housing 40. And after hardening this and comprising the sealing resin part 50, pressing of the magnetic core 20 and the coil 30 is cancelled | released.

Next, the magnetic core 20 and the coil 30 fixed to the housing 40 are arranged in the recess 41a of the housing 41, and these are pressed into the bottom surface 41b of the housing 41 from above to enter the recess 41a. Fill with resin material including heat dissipation filler. And after hardening this and comprising the sealing resin part 51, pressing of the magnetic core 20 or the coil 30 is cancelled | released.

Then, the reactor 10 according to the present embodiment is completed by attaching the coolers 60 and 61 to the bottom surfaces 40b and 41b of the casings 40 and 41 via the heat radiating gels 70 and 71, respectively.

Since the reactor 10 configured as described above fills the space between the magnetic core 20 and the coil 30 and the casings 40 and 41 with the sealing resin portions 50 and 51, the heat from the magnetic core 20 and the coil 30 is absorbed. Efficiently transmitted to the casings 40 and 41 and the coolers 60 and 61. The sealing resin portions 50 and 51 are in contact with the lower surface 20b or the upper surface 20a of the magnetic core 20, and the sealing resin portions 50 and 51 are filled so as to fill a gap between the magnetic core 20 and the coil 30. I have. In this way, heat dissipation can be promoted by filling the gap between the magnetic core 20 and the coil 30 with the sealing resin portions 50 and 51.

That is, the thermal conductivity of air is about 0.03 W / mK. For example, heat radiation can be promoted by providing the sealing resin portions 50 and 51 having a thermal conductivity of about 3 W / mK.

Further, while the sealing resin portions 50 and 51 are in contact with the lower surface 20b or the upper surface 20a of the magnetic core 20, the magnetic core 20 is exposed from the sealing resin portions 50 and 51 on both side surfaces 20c and 20d. Yes. For this reason, it becomes possible to keep the area | region where stress is applied to the magnetic core 20 by hardening shrinkage | contraction of the sealing resin parts 50 and 51 to the minimum. It is also possible to minimize the application of stress due to interference with the sealing resin portions 50 and 51 due to the magnetostriction of the magnetic core 20 itself.

Furthermore, the reactor 10 according to the present embodiment has a structure in which there is almost no pressure from the peripheral member against the magnetic core 20, for example, pressing by a leaf spring or the like from the radially outer side of the magnetic core 20. That is, even if the reactor 10 is pressurized by a leaf spring or the like, the reactor 10 is pressurized only in the direction of the central axis of the magnetic core 20, that is, from the side where the housings 40 and 41 are disposed.

As described above, it is generally known that characteristic deterioration occurs when stress is applied to the magnetic core, but the degree of this greatly varies depending on the direction in which the stress is applied. Specifically, the magnetostrictive effect is large when stress is applied in parallel with the main magnetic flux flowing through the magnetic core, and the characteristic deterioration is particularly large when such stress is applied.

When the entire magnetic coil is resin-sealed or the magnetic coil is pressed from the outside in the radial direction as in the reactor shown in Patent Document 1, the influence of the magnetostriction effect is large, and the characteristic deterioration of the magnetic core is increased.

However, unlike the reactor 10 of the present embodiment, the magnetic core 20 is not pressed from the outside in the radial direction, and even when pressed, the magnetic core 20 is pressed against the magnetic core 20 in the central axis direction. is there. For this reason, it is possible to reduce the influence of the magnetostrictive effect and to suppress characteristic deterioration.

As described above, the magnetostriction effect can be suppressed by almost eliminating the pressurization from the outside in the radial direction with respect to the magnetic core 20, and the pressurization from the sealing resin portions 50 and 51 accompanying the thermal deformation can also be suppressed. Furthermore, even if the magnetic core 20 to which the magnetic flux is applied when the reactor 10 is used expands, the contact portions with the sealing resin portions 50 and 51 are only the lower surface 20b and the upper surface 20a. For this reason, the stress applied from the sealing resin portions 50 and 51 due to the magnetostriction of the magnetic core 20 itself can be suppressed.

Therefore, it is possible to suppress deterioration of the characteristics of the magnetic core 20 due to resin sealing or pressurization, that is, increase in loss or decrease in magnetic permeability. And about heat dissipation, since both the magnetic core 20 and the coil 30 are in contact with the sealing resin portions 50 and 51, the casings 40 and 41 and the coolers 60 and 61 are interposed via the sealing resin portions 50 and 51. Can transfer heat well. Therefore, it becomes possible to set it as the reactor 10 which can thermally radiate favorably.

Further, as in Patent Document 1, in the case of a structure in which the whole of the magnetic core and the coil is covered with the sealing resin portion, heat dissipation is performed more favorably. Compared with this, there is a possibility that the heat radiation effect of the structure in which only a part of the magnetic core 20 and the coil 30 is covered by the sealing resin portions 50 and 51 like the reactor 10 of the present embodiment may be small. However, heat is mainly radiated from the portion of the magnetic core 20 or the coil 30 that is the closest to the casings 40 and 41, so that a sufficient heat radiating effect can be obtained even with the structure of this embodiment. be able to. In particular, in this embodiment, since the cross-sectional shape of the magnetic core 20 is flat, it is possible to increase the cooling area with respect to the volume of the magnetic core 20 and to ensure heat dissipation. Become.

Here, in the present embodiment, the cross-sectional shape in the direction orthogonal to the flow of magnetic flux in the magnetic core 20 is flattened so that the heat dissipation is good, but the flatness here is as follows. Defined in

FIG. 5 shows specifications assuming a case where the reactor 10 is applied as a vehicle boost converter reactor. The core loss indicates a loss during driving at 20 kW. The thermal conductivity of the core is a value that assumes a case where a magnetic core 20 in which iron powder is sandwiched between binder resins including a heat radiation filler and compressed is used. The cooling surface was assumed to radiate heat from both surfaces of the magnetic core 20 and the coil 30.
Based on these assumptions, the heat dissipation when heat was generated due to core loss was estimated. Specifically, as shown in FIG. 5, assuming that the center position of the magnetic core 20 is a heat generation surface, all the heat generation of the magnetic core 20 is radiated by the cooling surfaces on both sides, that is, the coolers 60 and 61. The thermal resistance Ra is expressed as Equation 1.

Further, when the magnetic core 20 is formed into a cubic shape and a flat shape with an increased cooling area, the respective dimensions and the like are defined as shown in FIG. 6 and the respective thermal resistances Ra are estimated.

Since the coil 30 has a high thermal conductivity, it is assumed that heat generation occurs at a place farthest from the cooling surface in order to ignore the influence and estimate the worst condition, so that the thermal resistance Ra is as shown in FIG. In addition, when the magnetic core 20 has a cubic shape, it is calculated as 2.5 ° C./W, and when it has a flat shape, it is calculated as 0.5 ° C./W.

Thus, heat radiation is promoted by taking the reactor in a flat shape, and the temperature of the magnetic core 20 can be lowered as compared with the case where the magnetic core 20 is in a cubic shape. For example, if the allowable heat generation temperature ΔT is 100 ° C., the heat generation temperature when the magnetic core 20 is in a cubic shape is 450 ° C., whereas it is 90 ° C. in the case of a flat shape, It can be seen that the allowable heat generation temperature ΔT is satisfied.

From this result, the entire reactor is resin-sealed as in Patent Document 1, whereas heat dissipation is ensured even when heat is released by resin-sealing only two surfaces as in this embodiment. Is possible. Then, based on the above calculation, the flat dimension range is defined as Equation 2 based on the cooling area of the magnetic core 20, that is, the ratio of the thickness dimension to the vertical and horizontal dimensions. It can be.

(Second Embodiment)
A second embodiment of the present disclosure will be described. In the present embodiment, the shape of the magnetic core 20 is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only different portions from the first embodiment will be described.

As shown in FIG. 7, in this embodiment, the corners of the magnetic core 20 are rounded. Specifically, the magnetic core 20 has an R shape formed by rounding a corner portion constituted by the lower surface 20b and both side surfaces 20c and 20d and a corner portion constituted by the upper surface 20a and both side surfaces 20c and 20d. .

Ideally, it is preferable that only the lower surface 20b and the upper surface 20a of the magnetic core 20 are sealed by the sealing resin portions 50 and 51, and the both side surfaces 20c and 20d are all exposed. However, actually, the sealing resin portions 50 and 51 may be formed so as to cover part of both side surfaces 20 c and 20 d in the manufacturing process of the reactor 10.

Therefore, concentration of stress received from the sealing resin parts 50 and 51 can be reduced by rounding the corners of the magnetic core 20 as in the present embodiment. Thereby, the pressurization to the magnetic core 20 accompanying the thermal deformation of the sealing resin parts 50 and 51 can be suppressed. Therefore, the characteristic deterioration of the magnetic core 20 can be further suppressed.

It should be noted that the height of the rounded portion of the magnetic core 20, that is, the distance from one surface of the magnetic core 20 that faces the housings 40 and 41 can be arbitrarily set. Preferably, the corners of the magnetic core 20 are R-shaped by the height embedded in the sealing resin portions 50 and 51.

(Third embodiment)
A third embodiment of the present disclosure will be described. In the present embodiment, the shapes of the casings 40 and 41 are changed with respect to the first and second embodiments. The other aspects are the same as those in the first and second embodiments. Only portions different from the embodiment will be described. In addition, although the case where this embodiment is applied with respect to the structure of 1st Embodiment is demonstrated here, this embodiment is applicable similarly to the structure of 2nd Embodiment.

As shown in FIG. 8, in this embodiment, the thickness of the bottom surfaces 40b and 41b in the casings 40 and 41 is made thicker on the outer edge side, that is, on the inner side than the side surfaces 40c and 41c side. Specifically, the bottom surface 40b, 41b has a convex surface that protrudes toward the magnetic core 20 or the coil 30 on the surface of the recesses 40a, 41a. Thereby, the intervals between the housings 40 and 41 and the magnetic core 20 and the coil 30 are made narrower toward the center of the magnetic core 20.

As shown in FIG. 9A, when the sealing resin portions 50 and 51 are formed by filling the casings 40 and 41 with the sealing resin, stress due to curing shrinkage after filling as shown by arrows in the figure. Is added to the casings 40 and 41. This stress acts toward the center of the casings 40 and 41, and there is a concern that the casings 40 and 41 are damaged and deformed as shown in FIG. 9B due to the stress concentration.

Therefore, as in the present embodiment, the thickness of the bottom surfaces 40b and 41b of the casings 40 and 41 is made thicker on the inner side than the side surfaces 40c and 41c, so that the stress concentration at the time of curing shrinkage of the sealing resin portions 50 and 51 is achieved. And the rigidity of the casings 40 and 41 can be increased. Thereby, breakage of the reactor 10 can be suppressed, and an increase in loss due to a decrease in the heat dissipation efficiency of the magnetic core 20 can be suppressed.

Moreover, the structure which becomes narrow as the space | interval of the housings 40 and 41 and the magnetic core 20 or the coil 30 goes to the center part of the magnetic core 20 only by changing the thickness of the bottom surfaces 40b and 41b of the housings 40 and 41. realizable. Therefore, it is not necessary to increase the size of the housings 40 and 41, and the housings 40 and 41 can be reduced in size and cost.

(Fourth embodiment)
A fourth embodiment of the present disclosure will be described with reference to FIGS. As shown in FIGS. 10 to 12, the reactor 110 of the present embodiment is configured to include a magnetic core 120, a coil 130, a housing 140, a sealing resin portion 150, a cooler 160, and the like. The reactor 110 is applied to generate a high output, such as a boost converter reactor mounted on an electric vehicle, a hybrid vehicle, or the like.

The magnetic core 120 is made of a soft magnetic material used as a core material, such as an iron-based alloy or an amorphous metal (eg, an iron-based amorphous material), and has a thermal conductivity of 1 to 50 W / mK, for example. In this embodiment, as shown in FIG. 10, the magnetic core 120 has a rectangular frame shape having two sets of two opposite sides of the upper surface shape. Also good. For example, the upper surface shape may be a circular frame shape. Further, the magnetic core 120 does not have to be a single member, and a plurality of divided cores may be integrated, or may be disposed so as to contact each other.

Further, as shown in FIG. 11, the magnetic core 120 has a quadrangular cross-sectional shape in a direction orthogonal to the flow of magnetic flux generated when the coil 130 is energized. More specifically, the magnetic core 120 has a flat shape in which a dimension in the width direction, which is a dimension in the left-right direction on the paper surface, is larger than a dimension in the thickness direction, which is a dimension in the vertical direction on the paper surface. In the present embodiment, the cross-sectional shape of the magnetic core 120 is rectangular. And the upper surface 120a and the lower surface 120b which comprise a long side are made to oppose the bottom face 140b which comprises the thermal radiation surface of the housing | casing 140 mentioned later. Then, each of the surfaces connecting the upper surface 120 a and the lower surface 120 b, that is, the inner peripheral side surface 120 c and the outer peripheral side surface 120 d constituting the short side, face the vertical direction with respect to the bottom surface of the casing 140. It is arranged on the body 140.

Further, in the present embodiment, the magnetic core 120 has an R shape with rounded corners constituted by the lower surface 120b and the both side surfaces 120c, 120d. In this way, by concentrating the corners of the magnetic core 120, the stress concentration received from the sealing resin portion 150 can be alleviated. The height of the rounded portion of the magnetic core 120, that is, the distance from one surface of the magnetic core 120 facing the housing 140 can be arbitrarily set. Preferably, the corners of the magnetic core 120 have an R shape corresponding to the height embedded in the sealing resin portion 150. The height of the rounded portion of the magnetic core 120 is about 10 mm so that the influence of stress can be reduced while taking into account thermal deformation of the sealing resin portion 150, variation in the filling amount, positional deviation of the magnetic core 120, and the like. And good.

The coil 130 is wound around the magnetic core 120, and is formed of, for example, a conductor wire such as copper with an insulating coating. As described above, in this embodiment, the magnetic core 120 has a quadrangular frame shape, but the coil 130 is wound around each of the two opposite sides of the magnetic core 120. The coil 130a wound around one side of the magnetic core 120 and the coil 130b wound around the other side are connected. In the case of this embodiment, the coil 130a and the coil 130b are connected via the connection part 130c in the downward position of the magnetic core 120, ie, the housing | casing 140 side. In addition, among the conductor wires constituting the coils 130 a and 130 b, the opposite side of the connecting portion 130 c is drawn wirings 130 aa and 130 ba drawn outside the sealing resin portion 150. The coil 110 is electrically connected to an external circuit through the lead wires 130aa and 130ba, so that the reactor 110 can be energized.

The housing 140 is a case that houses the magnetic core 120 and the coil 130, and is made of a material having a high thermal conductivity of, for example, 50 W / mK or more, such as aluminum. In the present embodiment, the housing 140 is configured as a separate body from the cooler 160, but these together constitute a cooling member, and even if the cooling member is configured by integrating them, good.

As shown in FIGS. 11 and 12, the housing 140 is constituted by a bottomed member having a recess 140a in which the magnetic core 120 and the coil 130 are accommodated. As shown in FIG. In this case, the bottom surface is a bottomed member having a quadrangular shape. Specifically, the housing 140 has a side surface 140c in addition to the bottom surface 140b constituting the heat radiating surface, and the bottom surface 140b and the side surface 140c constitute a recess 140a. As shown in FIG. 10, the magnetic core 120 and the coil 130 are accommodated so as to be disposed within a range surrounded by the side surface 140c and so that at least a part thereof enters the recess 140a in the depth direction.

More specifically, the recess 140a formed in the housing 140 is set to a depth at which the lower surface 120b of the magnetic core 120 is in close contact with a sealing resin portion 150 described later. That is, when the magnetic core 120 and the coil 130 are housed in the housing 140, the side surface 140c has an end opposite to the bottom surface 140b so that the side surface reaches a position farther from the bottom surface 140b than the bottom surface 120b of the magnetic core 120. A height of 140c is set.

Further, the bottom surface 140b of the housing 140 is provided with a core support part 140d that supports the magnetic core 120 and a coil support part 140e that supports the coil 130. The core support portion 140d and the coil support portion 140e are configured by protrusions provided so as to protrude from the bottom surface 140b.

The core support part 140d and the coil support part 140e are integrated with the housing 140. However, when the housing 140 is made of a conductive material, at least a part of the coil support portion 140e is made of an insulating material so that the housing 140 and the coil 130 can be insulated. As the insulating material, for example, resin or ceramics can be used. The coil support portion 140e can be integrated with the housing 140 by being integrally formed when the housing 140 is manufactured. Further, the core support portion 140d is made of a nonmagnetic material, and is preferably made of a nonmagnetic insulating material, for example, a resin, like the coil support portion 140e, from the viewpoint of insulation.

The shape of the core support part 140d and the coil support part 140e is arbitrary, but here it is a cylindrical shape with a flat tip. The protruding amounts of the core support portion 140d and the coil support portion 140e are different depending on the step between the magnetic core 120 and the coil 130 mounted thereon, and the core support portion 140d is more than the coil support portion 140e. The protruding amount is increased. Further, the magnetic core 120 and the coil 130 are supported by the core support part 140d and the coil support part 140e having different protrusion amounts, so that a gap between the magnetic core 120 and the coil 130 is secured, and the housing 140 and Insulation with the coil 130 is ensured.

The core support portion 140d is provided at a plurality of locations so that the magnetic core 120 can be supported with respect to the housing 140 in a state before the resin sealing by the sealing resin portion 150. In the case of this embodiment, the core support part 140d is provided in four places. The position where the core support portion 140d is formed may be anywhere as long as it can support the magnetic core 120 without tilting. However, here, the position away from the coil 130 and the position where the magnetic flux is small in the magnetic core 120. It is said. Specifically, the core support portion 140d is disposed at a position closer to the outer peripheral side surface 120d than the inner peripheral side surface 120c in the magnetic core 120. In the present embodiment, the core support portions 140d are disposed at the four corners of the magnetic core 120. . The number of core support portions 140d is arbitrary, and may be less than four or five or more.

The coil support portion 140e is provided at a plurality of locations so that the coil 130 can be supported with respect to the casing 140 in a state before resin sealing by the sealing resin portion 150. In the case of this embodiment, the coil support part 140e is provided in two places. The position where the coil support portion 140e is formed may be any position as long as the coil 130 can be supported without being inclined and a desired gap is formed between the coil 130 and the magnetic core 120. Here, the coil 130 is arranged on the outer side where heat is hard to accumulate, that is, on the opposite side of the coil 130 instead of the center side of the magnetic core 120. When the coil 130 is divided into two coils 130a and 130b as in the present embodiment, the outer side in the arrangement direction of the coils 130a and 130b, more preferably the outer side of the magnetic core 120. The coil support portion 140e may be disposed at the position. The number of coil support portions 140e is arbitrary, and more stable support is possible if a plurality of, for example two, coils are provided for each of the coils 130a and 130b.

The sealing resin part 150 is a binder resin containing a heat radiation filler. For example, alumina or the like is used as the heat dissipating filler, and epoxy resin or silicone is used as the resin material. The sealing resin portion 150 made of such a material has a thermal conductivity of 0.7 to 4 W / mK, for example, 3 W / mK, for example.

The sealing resin portion 150 is filled and cured in a recess 140 a formed in the housing 140. The sealing resin portion 150 is formed up to a position where the portion of the coil 130 located below the magnetic core 120 is immersed and at least the lower surface 120b of the magnetic core 120 contacts. As the sealing resin portion 150, a material having a low viscosity in a state before being cured is applied, so that the space between the magnetic core 120 and the coil 130 or between the magnetic core 120 and the housing 140 can be filled without a gap. I have to.

However, the sealing resin portion 150 is in contact with the lower surface 120b of the magnetic core 120, but does not cover more than half of the upper surface 120a and both side surfaces 120c, 120d, preferably 90% or more. The magnetic core 120 is exposed from the sealing resin portion 150. Considering the stress received by the magnetic core 120 from the sealing resin portion 150, it is preferable that the sealing resin portion 150 is formed up to a position in contact with the lower surface 120 b of the magnetic core 120. However, in consideration of variation in the curing shrinkage of the resin, the cured sealing resin portion 150 may be separated from the lower surface 120b. Therefore, the sealing resin portion 150 is slightly closer to the upper surface 120a side than the lower surface 120b. Is more preferable. Therefore, the formation position of the sealing resin portion 150 is set to the above position.

The cooler 160 constitutes a part of the cooling member. In the case of the present embodiment, connectivity is improved by being bonded to the bottom surface 140b of the housing 140 via a heat radiating gel 170 having a high thermal conductivity such as a silicone gel. For example, in the case of silicone-based gel, the thermal conductivity is about 1 W / mK, and heat transfer from the housing 140 to the cooler 160 can be favorably performed by thin coating.

The cooler 160 may be an air-cooled type or a water-cooled type. In the case of the air cooling type, the cooler 160 may be a heat sink composed of, for example, a simple high heat conductive plate, or a heat radiating fin is provided on the back side opposite to the coil 130, the magnetic core 120, the housing 140, and the like. It may be a heat sink provided. Further, a structure may be employed in which a refrigerant passage is formed inside the cooler 160 and the refrigerant flows in the refrigerant passage.

As described above, the reactor 110 according to the present embodiment is configured. The reactor 110 configured as described above is manufactured as follows.

First, the magnetic core 120, the coil 130, and the housing 140 are prepared. It arrange | positions so that the coil 130 may be wound with respect to the magnetic core 120. FIG. For example, the magnetic core 120 is composed of two U-shaped cores and the like, and the tips of the two U-shaped cores are inserted into the coil 130 from opposite directions so that the coil 130 is wound around the magnetic core 120. A rotated structure can be constructed.

Then, the magnetic core 120 and the coil 130 are arranged in the recess 140a of the housing 140, and a resin material including a heat radiation filler is filled in the recess 140a in a state where they are pressed from above to the bottom surface 140b side of the housing 140. And after hardening this and comprising the sealing resin part 150, pressing of the magnetic core 120 and the coil 130 is cancelled | released. Then, the reactor 110 concerning this embodiment is completed by sticking the cooler 160 to the bottom face 140b of the housing | casing 140 via the thermal radiation gel 170. FIG.

Since the reactor 110 configured as described above fills the space between the magnetic core 120 and the coil 130 and the casing 140 with the sealing resin portion 150, the casing 110 efficiently heats the magnetic core 120 and the coil 130. 140 and cooler 160. And the sealing resin part 150 and the lower surface 120b of the magnetic core 120 are contacting, and the sealing resin part 150 is provided so that the clearance gap between the magnetic core 120 and the coil 130 may be filled up. In this way, heat radiation can be promoted by filling the gap between the magnetic core 120 and the coil 130 with the sealing resin portion 150.

That is, the thermal conductivity of air is about 0.03 W / mK. For example, heat radiation can be promoted by including the sealing resin portion 150 having a thermal conductivity of about 3 W / mK.

In addition, while the sealing resin portion 150 is in contact with the lower surface 120 b of the magnetic core 120, the upper surface 120 a and both side surfaces 120 c and 120 d are not substantially covered, and the magnetic core 120 is exposed from the sealing resin portion 150. I am doing so. For this reason, it is possible to minimize the region where the stress is applied to the magnetic core 120 due to the curing shrinkage of the sealing resin portion 150. It is also possible to minimize the application of stress due to interference with the sealing resin portion 150 due to the magnetostriction of the magnetic core 120 itself.

Thus, there is no pressurization from the peripheral member against the magnetic core 120, for example, pressing by a leaf spring, and pressurization from the sealing resin portion 150 accompanying thermal deformation can be suppressed. Further, even if the magnetic core 120 to which magnetic flux is applied during the use of the reactor 110 is expanded, the contact portion with the sealing resin portion 150 is almost only the lower surface 120b, which is caused by the magnetostriction of the magnetic core 120 itself. The stress applied from the sealing resin part 150 can be suppressed.

Therefore, it is possible to suppress the deterioration of the characteristics of the magnetic core 120 due to resin sealing or pressurization, that is, increase in loss or decrease in magnetic permeability. As for heat radiation, since both the magnetic core 120 and the coil 130 are in contact with the sealing resin portion 150, heat can be transferred well to the casing 140 and the cooler 160 via the sealing resin portion 150. . Therefore, it becomes possible to make the reactor 110 capable of radiating heat well.

In addition, like patent document 1, in the case of the structure which covers the whole of a magnetic core and a coil by a sealing resin part, heat radiation will be performed more favorably. Compared with this, there is a possibility that the heat radiation effect of a structure in which only a part of the magnetic core 120 and the coil 130 is covered by the sealing resin portion 150 as in the reactor 110 of the present embodiment may be small. However, heat is mainly radiated from the portion of the magnetic core 120 or coil 130 that is the closest to the housing 140, so that a sufficient heat radiating effect can be obtained even with the structure of this embodiment. it can. In particular, in the present embodiment, since the cross-sectional shape of the magnetic core 120 is flat, it is possible to increase the cooling area with respect to the volume of the magnetic core 120 and to ensure heat dissipation. Become.

Here, in this embodiment, the cross-sectional shape in the direction orthogonal to the flow of magnetic flux in the magnetic core 120 is flattened to improve heat dissipation, but the flatness here is as follows. Defined in

FIG. 13 shows specifications assuming that the reactor 110 is applied as a vehicle boost converter reactor. The core loss indicates a loss during driving at 10 kW. The thermal conductivity of the core is a value that assumes a case where a magnetic core 120 is used in which iron powder is sandwiched between binder resins including a heat radiation filler and compressed. The cooling surface was assumed to radiate heat from only one side of the magnetic core 120 and the coil 130.
Based on these assumptions, the heat dissipation when heat was generated due to core loss was estimated. Specifically, assuming that the center position of the magnetic core 120 is a heat generation surface, the heat resistance when all the heat generation of the magnetic core 120 is radiated by the cooling surface on one side, that is, the cooler 160, is expressed as Equation 3. It is.

Further, when the magnetic core 120 is in a cubic shape and in a flat shape with an increased cooling area, the respective dimensions are defined as shown in FIG. 14 and the respective thermal resistances are estimated.

Since the thermal conductivity of the coil 130 is high, it is assumed that heat is generated at a place farthest from the cooling surface in order to ignore the influence and estimate the worst condition, as shown in FIG. When the magnetic core 120 has a cubic shape, it is calculated as 5 ° C./W, and when it has a flat shape, it is calculated as 1 ° C./W.

Thus, heat radiation is promoted by taking the reactor in a flat shape, and the temperature of the magnetic core 120 can be lowered as compared with the case where the magnetic core 120 is in a cubic shape. For example, when the allowable heat generation temperature ΔT is 100 ° C., the heat generation temperature when the magnetic core 120 is in a cubic shape is 455 ° C., whereas in the case of a flat shape, it is 92 ° C. It can be seen that the allowable heat generation temperature ΔT is satisfied.

From this result, the entire reactor was resin-sealed as in Patent Document 1, whereas heat dissipation can be ensured even when heat is released by resin-sealing only on one side as in this embodiment. It becomes possible. Then, based on the above calculation, the flat dimension range is defined as Equation 4 based on the cooling area of the magnetic core 120, that is, the ratio of the thickness dimension to the vertical and horizontal dimensions. It can be. That is, when the short side in the flat rectangular shape is taken as the numerator and the value obtained by multiplying the two long sides is taken as the denominator, it is set to 3/100 or less.

In the present embodiment, the core support portion 140d is formed at a position closer to the outer peripheral side surface 120d than the inner peripheral side surface 120c of the magnetic core 120. For this reason, the position with little magnetic flux in the magnetic core 120 can be supported by the core support portion 140d. That is, a large amount of magnetic flux collects in the inner periphery of the magnetic core 120 in the reactor 110. The characteristic deterioration due to the pressurization of the magnetic core 120 has a larger influence as the magnetic flux collects more. Therefore, it is possible to further suppress the characteristic deterioration of the magnetic core 120 by setting the location of the core support portion 140d as in the present embodiment.

Further, in this embodiment, the coil support portion 140e is disposed outside the arrangement direction of the coils 130a and 130b. In the reactor 110, heat generation is concentrated from the cooler 160 to the central portion where the thermal resistance is high, and therefore the coil support portion 140e is disposed at a position away from the central portion where heat is accumulated. Thereby, it is possible to further suppress an increase in loss of reactor 110.

(Other embodiments)
The present disclosure is not limited to the above-described embodiment, and can be appropriately changed within the scope described in the claims.

For example, the shape of the magnetic core 20, the coil 30, and the casings 40 and 41 described in the above embodiments is merely an example, and other shapes may be used.

In addition, although the said embodiment demonstrated the case where the reactors 10 and 110 were applied to the reactor for step-up converters etc. which are mounted in an electric vehicle, a hybrid vehicle, etc., this is only an example of an application example and others. It is also possible to apply to For example, the reactors 10 and 110 can be applied to a PFC step-up reactor or a smoothing choke for a charger.

Moreover, in the said embodiment, although the reactors 10 and 110 are comprised by two U-shaped cores, the reactors 10 and 110 can also be comprised by two E-shaped cores or several I-shaped cores, The said embodiment The same effect can be obtained.

In the above embodiment, the magnetic core 120 has a flat shape, but this is to obtain higher heat dissipation, and the height of the magnetic core 120 may be appropriately changed according to the heat dissipation. The height can be set arbitrarily. For example, the magnetic core 120 may be configured with a square cross-sectional shape.

In the above-described embodiment, the magnetic core 120 is rectangular, and the corner of the magnetic core 120 is rounded on the sealing resin portion 150 side. However, the corner may not be rounded. Moreover, the structure which chamfered the corner | angular part by the side of the sealing resin part 150 among the magnetic cores 120 may be sufficient.

Claims (15)

1. A magnetic core (20);
   A coil (30) wound around the magnetic core;
   A first cooling member (40) that is disposed on both sides of the magnetic core and the coil and includes a heat radiation surface (40b, 41b) on which the magnetic core and the coil are disposed, and that radiates heat from the magnetic core and the coil. 60) and the second cooling member (41, 61);
   Filling the space between the heat dissipation surface of the first cooling member and the magnetic core seals the lower surface (20b) of the magnetic core that is on the heat dissipation surface side and the second cooling member. Both side surfaces connected to the heat dissipation surface of the magnetic core while sealing the upper surface (20a) on the heat dissipation surface side of the magnetic core by being filled between the heat dissipation surface and the magnetic core. A first sealing resin portion (50) and a second sealing resin portion (51) formed to expose (20c, 20d),
   The magnetic core has a cross-sectional shape on a plane orthogonal to the flow of magnetic flux generated when the coil is energized, and a dimension in the same direction as the direction in which the first cooling member and the second cooling member are arranged. A reactor having a flat shape in which a dimension in a direction perpendicular to the direction is further increased.
2. The magnetic core has a quadrangular cross-sectional shape in a plane perpendicular to the flow of magnetic flux generated when the coil is energized, and the sides constituting the upper surface and the lower surface of the quadrilateral shape The reactor according to claim 1, wherein is a flat rectangular shape having a long side and a side constituting the both side surfaces being a short side.
3. The reactor according to claim 2, wherein a corner portion of the magnetic core is rounded by the lower surface and the both side surfaces.
4. Both the first cooling member and the second cooling member include a housing (40, 41) including a bottom surface (40b, 41b) that constitutes the heat dissipation surface, and a cooler (60, 60) bonded to the housing. 61), and
   The bottom surface of the casing provided in each of the first cooling member and the second cooling member has a convex shape protruding toward the magnetic core and the coil, and the thickness of the bottom surface is larger than the outer edge side of the bottom surface. 4. The distance between the bottom surface and the magnetic core and the coil is narrowed toward the center of the bottom surface by increasing the thickness of the inner side. Reactor.
5. A magnetic core (120);
   A coil (130) wound around the magnetic core;
   A cooling member (140, 160) including a heat radiating surface (140b) on which the magnetic core and the coil are disposed, and radiating heat from the magnetic core and the coil;
   A core support part (140d) provided to protrude from the heat dissipation surface and supporting the magnetic core;
   A coil support part (140e) provided to protrude from the heat dissipation surface and supporting the coil;
   The magnetic core is supported by the core support portion, and is filled between the magnetic cores from the heat dissipation surface in a state where the coil is supported by the coil support portion. A reactor having a sealing resin portion (150) formed so as to expose a surface opposite to the heat dissipation surface of the magnetic core while sealing a surface on the heat dissipation surface side.
6. The magnetic core has a lower surface (120b) that faces the heat dissipation surface, an upper surface (120a) that is opposite to the first surface, and side surfaces (120c and 120d) that connect the upper surface and the lower surface, The reactor according to claim 5, wherein a cross-sectional shape in a direction orthogonal to a flow of magnetic flux generated when energizing the coil is a quadrangular shape.
7. The cross-sectional shape of the magnetic core is a flat rectangular shape in which the sides constituting the upper surface and the lower surface are long sides and the sides constituting the side surfaces are short sides in the quadrangular shape. Item 7. The reactor according to Item 6.
8. The reactor according to claim 7, wherein the short side of the flat rectangular shape is taken as a numerator and a value obtained by multiplying the two long sides as a denominator is 3/100 or less.
9. The reactor according to any one of claims 6 to 8, wherein a corner portion of the magnetic core is rounded by the lower surface and the side surface.
10. The magnetic core has a cross-sectional shape in a direction perpendicular to the flow of magnetic flux generated when the coil is energized in a direction parallel to the heat dissipation surface from a dimension in a normal direction to the heat dissipation surface. The reactor according to claim 5, wherein the reactor has a flat shape with increased dimensions.
11. The magnetic core has a frame shape when viewed from the normal direction of the heat dissipation surface, and an inner peripheral side surface (120c) constituting the inner peripheral side of the frame shape and an outer peripheral side surface (120d) constituting the outer peripheral side. And
    The said core support part is supporting the said magnetic core in the position away from the said coil, and the position of the said outer peripheral side surface rather than the said inner peripheral side surface among the said magnetic cores. Reactor described in 1.
12. The magnetic core has a rectangular frame shape when viewed from the normal direction of the heat dissipation surface,
    The reactor according to claim 11, wherein the core support portion is disposed at four corners of the magnetic core.
13. The coil is wound around the magnetic core having the frame shape,
    The reactor according to any one of claims 5 to 12, wherein the coil support portion is disposed on an outer side of the coil that is opposite to a center side of the magnetic core.
14. The reactor according to claim 13, wherein the coil support part supports the coil outside the magnetic core.
15. The core support portion is made of an insulating material that at least partially insulates the magnetic core and the heat dissipation surface,
    The reactor according to any one of claims 5 to 14, wherein at least a part of the coil support portion is made of an insulating material that insulates the coil and the heat dissipation surface.

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