JP2012134532A - Reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor which has more effective heat radiation, and to provide a manufacturing method of the reactor.SOLUTION: A reactor includes: a core 1; a coil 2 wound around the core 1; a case 3 housing the core 1 in which the coil 2 is formed; and a sealing material sealing the core 1 and the coil 2 in the case 3. A bobbin cover for positioning the core 1 in which the coil 2 is formed in the case 3 does not exist between the case 3 and the coil 2. The electrical insulation between the coil 2 and the case 3 is secured by the sealing material disposed therebetween. The reactor achieves excellent heat radiation without using the bobbin cover.

Description

  The present invention relates to a reactor used for components such as a buck-boost converter and a method for manufacturing the same. In particular, it relates to a reactor having excellent heat dissipation characteristics.

  In recent years, a battery, an inverter, and a three-phase AC motor for traveling are generally used in hybrid vehicles that are becoming popular. Among them, the inverter includes a converter unit that performs direct current step-up / step-down and an inverter unit that performs mutual conversion between direct current and alternating current. For example, the converter unit boosts a battery voltage of about 200V to a maximum of about 500V during driving and supplies power to the inverter unit. During regeneration, the converter unit steps down the direct current output from the motor through the inverter unit to a voltage suitable for the battery. The battery is charging. Further, the inverter unit converts the direct current boosted by the converter unit during traveling into a predetermined alternating current and feeds the motor, and during regeneration, converts the alternating current output from the motor into direct current and outputs it to the converter unit.

  This converter unit performs step-up / step-down by turning on / off the switching element, and one of the components is a reactor. Reactor makes use of the nature of the coil that tries to prevent changes in the current that flows through the circuit, and smoothes the change when the current is going to increase or decrease due to external factors such as switching on and off. Have

  An example of this reactor is shown in FIGS. 8 and 9 (Patent Document 1 as a document disclosing a similar technique). The reactor includes a ring-shaped core 1 made of a magnetic material and a coil 2 wound around a part of the core 1 as main constituent members. The bottom surface and both side surfaces of the core 1 on which the coil 2 is formed are covered with a plastic and concave bobbin cover 10 as shown in FIG. 8, and in this state, as shown in FIG. It is stored in. The main function of the bobbin cover 10 is to ensure insulation between the coil 2 and the case 3 by positioning the core 1 on which the coil 2 is formed at a predetermined position in the case 3. Then, potting resin (sealing material: not shown) is filled in the case 3 in which the core 1 and the coil 2 are accommodated.

Japanese Patent Laid-Open No. 2006-351719 FIG.

  However, since the conventional reactor uses the bobbin cover 10, there is a problem that the heat dissipation characteristics of the core 1 and the coil 2 are not sufficient.

  During the operation of the reactor, the coil 2 and the core 1 generate heat. This heat is preferably radiated quickly, but in the conventional reactor, since the plastic bobbin cover 10 exists in the heat radiation path, it is difficult to sufficiently radiate the heat. If this heat radiation cannot be sufficiently performed, the maximum temperature reached by the coil 2 or the core 1 rises, the sealing material may be damaged by heat, and the insulation between the coil 2 and the case 3 may be broken. In particular, in order to make a reactor that can handle a high voltage and a large current, further improvement in heat dissipation characteristics is required.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a reactor having excellent heat dissipation characteristics. Another object of the present invention is to provide a method for manufacturing a reactor having excellent heat dissipation characteristics.

  The reactor of the present invention includes a core, a coil wound around the core, a case that houses the core on which the coil is formed, and a sealing material that seals the core and the coil in the case. In this reactor, there is no bobbin cover for aligning the core in which the coil is formed between the case and the coil, and the insulation between the coil and the case is ensured by a sealing material. And

  According to this configuration, since there is no bobbin cover that has been conventionally interposed between the coil and the case and has been an obstacle to heat dissipation from the core and the coil, a reactor with higher heat dissipation can be configured. . Therefore, it can be set as the reactor which can respond to a higher voltage and a larger current. On the other hand, the insulation between the coil and the case can be sufficiently secured by the sealing material.

  In the reactor according to the present invention, the outer periphery of the core is further provided with an insulative brim that abuts the end of the coil, and the brim is configured to align the core on which the coil is formed with the case. It is preferable to do.

  According to this configuration, the position of the core in which the coil is formed in the case can be defined by the collar without using the bobbin cover, so the coil and the case can be used without using a special jig or the like. A distance from the inner surface can be appropriately maintained. Along with this, the insulation between the coil and the case can be reliably maintained.

  Moreover, the reactor of this invention WHEREIN: It is preferable to provide an insulating thin film coating in the location which opposes a coil among the said case inner surfaces.

  According to this configuration, the insulating property between the coil and the case can be further ensured by providing the insulating thin film coating at a predetermined position on the inner surface of the case. That is, the insulation between the coil and the case by the sealing material can be reinforced.

  Furthermore, in the reactor of the present invention, it is preferable that a portion of the core that is not covered with the coil is brought into contact with the inner surface of the case to support the core in the case. At this time, it is preferable to set the distance between the support surface of the core and the case bottom surface in the case so that a predetermined insulation distance can be secured between the case bottom surface and the coil in the support state of the core.

  According to this configuration, by directly supporting the exposed portion of the core in contact with the inner surface of the case, direct heat dissipation from the core to the case can be performed. In addition, a sealing material is provided between the coil and the case bottom surface in order to set the distance between the support surface of the core and the case bottom surface in the case so that a predetermined insulation distance can be secured between the case bottom surface and the coil. The space | interval which is easy to fill can be ensured, and the insulation with a coil and a case bottom face can be ensured.

On the other hand, the reactor manufacturing method of the present invention includes the following steps.
A step of preparing an assembly in which a coil is formed on the outer periphery of the core.
After positioning the assembly in the case with a spacer interposed between the assembly and the inner surface of the case so that a predetermined insulation distance can be maintained between the side surface of the coil and the inner surface of the case in this assembly. , Removing the spacer.
A step of filling the case with a sealing material while the assembly is positioned in the case.

  According to this configuration, when the assembly composed of the core and the coil is housed in the case, the spacing between the coil and the case inner surface can be appropriately ensured by using the spacer. Therefore, a reactor in which the insulation distance between the coil and the case inner surface is properly maintained can be obtained without using a bobbin cover.

  According to the reactor of the present invention, a reactor excellent in heat dissipation can be obtained without using a bobbin cover.

  Moreover, according to the manufacturing method of this invention reactor, the reactor excellent in heat dissipation can be comprised, without using a bobbin cover, and the reactor by which the insulation with a coil and a case was ensured can be obtained.

1 is a perspective view of a reactor of the present invention in Example 1. FIG. It is a disassembled perspective view of the core used for the reactor of Example 1. FIG. (A) is a longitudinal cross-sectional view of the reactor of Example 1, (B) is a longitudinal cross-sectional view of the conventional reactor. (A) is a cross-sectional view of a conventional reactor, and (B) is an enlarged view of a region surrounded by a broken line in FIG. FIG. 3 is an enlarged cross-sectional view of a reactor side surface portion in the first embodiment. It is a perspective view of this invention reactor in Example 2. FIG. In the reactor of Example 3, it is a perspective view of the case which shows the coating | coated area | region of thin film coating. It is a perspective view which shows the state which combined the core, the coil, and the bobbin in the conventional reactor. It is a perspective view which shows the conventional reactor.

  The reactor of the present invention includes a core, a coil, a case, and a sealing material. Furthermore, usually, an insulator that insulates the core and the coil is also used as a constituent member of the reactor. And this reactor is not provided with the bobbin cover conventionally used in order to align a coil (core) and a case. Hereinafter, each component will be described in more detail.

<Core>
The core is typically configured in an annular block shape. The core usually includes a plurality of magnetic material portions and a plurality of gap portions, and each magnetic material portion is configured to be joined via the gap portions. As the magnetic material portion, for example, a compacted body of soft magnetic powder or a laminate of electromagnetic steel sheets can be suitably used. The gap portion is interposed between the magnetic material portions, is used to adjust the inductance of the core, and is made of a nonmagnetic material. Examples of the material of the gap part include alumina. In addition, it is possible to use a core that is made of a compacted body with adjusted permeability and does not have a gap.

<Coil>
The coil is configured by winding a winding made of a conductor and an insulating coating covering the periphery of the conductor in a spiral shape around a predetermined portion of the core. A metal material excellent in conductivity can be suitably used for the conductor, and enamel can be suitably used for the insulating coating. Various forms such as a circle, an ellipse, and a polygon can be used for the cross section of the winding. If a coil is comprised with a polygonal coil | winding, a space factor will be easy to raise compared with the case where a circular coil | winding is used. When a winding having a rectangular cross section is used, edgewise winding can be suitably used as a winding method of the winding.

<Case>
The case stores the above-described assembly having the core and the coil, and dissipates heat from the assembly through the case. Therefore, the case has a cooling mechanism and is made of a material having high heat dissipation. Specifically, a material excellent in thermal conductivity, particularly a metal material can be suitably used. Aluminum or aluminum alloy is particularly preferable.

  This case is usually a container having both side surfaces, both end surfaces, and a bottom portion, and an open top. At that time, step portions are formed on both ends of the bottom portion, the upper surface of each step portion is used as a support surface of the core, and a bottom surface lower than the support surface is formed between both step portions. It is preferable to form a gap between the two. If the case of this form is used, the core can be held in direct contact with the support surface, so that efficient heat dissipation from the core through the case can be performed. In addition, a sealing material is provided between the bottom surface of the case and the coil by making the step between the support surface and the bottom surface of the case larger than the distance from the core surface contacting the support surface to the outer peripheral surface of the coil. A gap for filling can be formed. By filling the gap with the sealing material, it is possible to ensure insulation between the bottom surface of the case and the coil.

  An insulating thin film coating may be formed at a predetermined position on the inner surface of the case. By forming the thin film coating, the coil and the case can be more reliably insulated.

  As a material for the thin film coating, an inorganic insulating material having excellent thermal conductivity such as aluminum nitride, boron nitride, silicon nitride, silicon carbide, titanium oxide, or the like can be suitably used. These thin films can be formed by a PVD method or a CVD method. In addition, when the case is made of aluminum, a thin film coating can also be formed by applying an alumite treatment. Alternatively, a thin film coating can be formed by applying an insulating tape such as Kapton tape. The portion to be coated with the thin film may be the entire inner surface of the case, or only the portion facing the coil. For example, both side surfaces of the case and the inside of the bottom surface of the case can be cited.

  In the reactor of the present invention, since the insulation between the coil and the case is provided by a sealing material, the thin film coating may be thin. Considering that the thickness of the bobbin cover has conventionally been 3 mm or more, the thickness of the thin film coating is preferably 1 mm or less.

<Encapsulant>
The sealing material is (1) the function to ensure insulation between the coil and the case, (2) the function to hold the core and the components housed in the case in the case, and (3) the vibration of the core. Has a function of reducing transmission to the outside. As this sealing material, an insulating material that is not damaged at the maximum temperature reached by the core or coil can be suitably used. For example, an epoxy resin, a urethane resin, etc. are mentioned. As this sealing material, a porous material excellent in sound absorption of noise generated by reactor vibration can also be used. Specifically, foamed plastic, glass wool, rock wool and the like can be suitably used. Examples of the foamed plastic include foamed polystyrene, foamed polyethylene, foamed polypropylene, foamed polyurethane, and foamed rubber. Examples of the foamed rubber include synthetic rubbers such as foamed chloroprene rubber, foamed ethylene propylene rubber, and foamed silicon rubber.

  In the case of the reactor of the present invention, only the sealing material basically exists between the coil and the case, except when the above-described thin film coating is formed on the inner surface of the case. Therefore, the thickness of the sealing material is set to a thickness that can ensure insulation between the coil and the case. Although the preferable thickness of the sealing material depends on the material of the sealing material, 2.5 mm or less is preferable in terms of both insulation and heat dissipation. When a thin film coating is formed on the case, the thickness of the sealing material may be reduced according to the thickness.

<Insulator>
When the coil is formed on the core, an insulator made of an insulating material is usually interposed between the coils. This insulator is for ensuring insulation between the core and the coil even if the insulation coating of the coil is damaged. The insulator is provided on the cylindrical body covering the outer periphery of the core and the end of the coil. And a plate-like collar portion to be brought into contact with. Here, the collar part may be used as a guide for positioning the assembly having the core and the coil in the case by configuring the collar part to be wider, and is considerably smaller than the inner width of the case. It may be used as a width. In the latter case, alignment with respect to the case may be performed using a spacer described later. Various plastics are used as the constituent material of the insulator of the assembly, but a plastic material excellent in heat resistance can be suitably used because it is interposed between the core and the coil, which are heating elements. For example, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), liquid crystal polymer (LCP) and the like can be suitably used.

  In the conventional reactor, the concave bobbin cover is disposed so as to cover the majority of the outer periphery of the coil so as to sandwich the pair of brim portions. However, in the reactor of the present invention, the bobbin cover is not used. Thereby, the heat dissipation characteristics of the core and the coil can be improved.

<Reactor manufacturing method>
When manufacturing the reactor of the present invention, it is important to accurately position the assembly in which the coil is formed on the core in the case so that an insulation distance between the coil and the case can be secured. In the conventional reactor, the bobbin cover is used for this positioning. However, since the bobbin cover is not used in the reactor of the present invention, a spacer is temporarily used when the assembly is stored in the case.

  As the spacer, a plate material used for maintaining a gap between the coil and the case side surface can be suitably used. What is necessary is just to set the thickness of this spacer to the thickness which can hold | maintain the insulation between a coil and a case in the state which filled the sealing material between the coil and the case. For example, a spacer having a thickness comparable to or less than that of a bobbin cover used in a conventional reactor may be used.

  As this spacer, a material / form which does not damage the coil insulation coating in use can be suitably used. Specifically, a form made of a plastic material and having a smooth surface is preferable. Further, if a concave spacer is used and its end portion is inserted between the core and the case, the distance between both side surfaces of the case and both side surfaces of the coil can be defined simultaneously.

  If the distance between the coil and the case can be adjusted by the spacer, the spacer is removed, and the sealing material is filled in the case while maintaining the position of the assembly in the case. The insulation of the case can be maintained. Therefore, it is possible to reduce the number of components of the reactor.

Example 1
<Reactor configuration>
An embodiment of the reactor of the present invention will be described with reference to FIGS. 1, 2, and 3 (A). The reactor includes a core 1, a coil 2, a case 3, and a sealing material (not shown) as main components. In addition, an insulator 4 for insulating between the core 1 and the coil 2 is also provided.

  First, as shown in FIG. 2, the core 1 includes a magnetic material portion 1M and a gap portion 1G. Among them, the magnetic part 1M is formed of a compacted body of soft magnetic powder, and has a rectangular parallelepiped normal block piece 1N and a bent U-shaped block piece 1U. On the other hand, the gap portion 1G is formed of a rectangular plate made of alumina. In this example, four normal block pieces 1N and two U-shaped block pieces 1U are used, and a pair of normal block pieces 1N arranged in parallel is arranged between a pair of U-shaped block pieces 1U. A total of six gap portions 1G are interposed between the block pieces 1N and 1U and bonded to each other to form an annular core 1.

  In this core 1, a coil 2 is formed by winding a winding around the outer periphery of a straight portion formed by the normal block piece 1N and both ends of the U-shaped block piece 1U (FIGS. 1, 3A). )). In this example, the coil 2 was formed by using an edgewise winding of a winding in which an enamel coating was formed on the surface of a copper wire having a flat rectangular cross section. This winding is wound in one direction from one end side to the other end side in one linear portion of the core 1, and then moves to the other straight portion as it is, from the other end side of the other linear portion to one end side. Is wound in the opposite direction to form a coil that covers both linear portions of the core 1. That is, in the state of the assembly in which the coil 2 is formed on the core 1, the linear portion of the core 1 is covered with the coil 2, and the bent portion (U-shaped block piece 1U) of the core is exposed from the coil 2. Yes.

  On the other hand, as shown in FIG. 1 and FIG. 3 (A), the case 3 has a container shape with an open top, and has both side surfaces 3S (FIG. 1), both end surfaces 3E (FIG. 1), and bottom 3B (FIG. (A)). In this example, the case 3 is formed by die-casting an aluminum alloy, and the case surface is not subjected to an alumite treatment. Here, as shown in FIG. 3A, the bottom portion 3B of the case 3 is formed with step portions 3BS on both ends, and the surface of the step portion 3BS serves as a support surface of the core 1. As already described, a part of the core 1 is exposed from the coil 2. When the assembly is stored in the case, the exposed core 1 abuts against the surface of the stepped portion 3BS so that the assembly is supported in the case 3 and the core 1 to the case 3 is used as a heat dissipation path. Heat dissipation is possible. Further, the end of the core 1, that is, the inner surface of the case end surface facing the U-shaped block piece 1U is also shaped along the curved outer surface of the U-shaped block piece 1U. Heat dissipation is possible. On the other hand, between the two stepped portions 3BS is a bottom surface 3BB formed lower than the support surface of the core 1. Then, by making the step between the support surface and the bottom surface 3BB larger than the distance from the exposed surface of the core 1 to the outer peripheral surface of the coil, when the assembly is stored in the case 3, the coil 2 and the bottom surface 3BB A gap can be formed between them. The gap is filled with a sealing material as will be described later, thereby ensuring insulation between the coil 2 and the case 3. Comparing the arrangement relationship between the case bottom and the coil with a conventional reactor, as shown in FIG. 3B, in the conventional reactor, a bobbin cover 10 is interposed between the coil 2 and the case bottom 3BB. On the other hand, in the reactor of the present example, it can be seen that a gap is formed at a location where the bobbin cover is removed.

  Further, in this example, a housing portion 3R for the leaf spring 5 is formed between one step 3BS of the case and one end surface 3E. This housing part 3R is a groove along the depth direction of the case 3, and a substantially U-shaped leaf spring 5 is housed in the housing part 3R, so that the core 1 is moved to the other end face side by the repulsive force of the leaf spring 5. To absorb the vibration of the core 1. One end side of the leaf spring 5 is provided with a pressing surface 5T that is parallel to the case bottom surface 3BB in the storage state in the storage portion 3R. The pressing surface 5T is pressed by the stopper 6, and the leaf spring 5 is I try not to fall off. The stopper 6 is an aluminum alloy block that is fixed to one end surface 3E of the case 3 with a screw 7.

  A screw hole (not shown) for screwing the stay 8 that presses the core 1 to the case 3 is formed at a corner portion constituted by the other end surface 3E and both side surfaces 3S of the case 3. When the assembly is stored in the case 3, stays 8 that are long and thin plate-like and have through holes at both ends are disposed on the upper surface of the core 1 exposed from the coil 2. By aligning the through hole of the stay 8 with the screw hole and fixing the stay 8 with the screw 9, the core 1 is prevented from falling off the case 3. In this example, one side of the core 1 is pressed by the leaf spring 5, and the other side of the core 1 is fixed by the stay 8 and the screw 9. However, both sides of the core 1 are fixed by the stay and the screw. It is good also as a structure fixed by.

  In addition, the bottom surface 3BB of the case 3 is formed with a mountain-shaped protrusion (not shown) along the center line of the both side surfaces 3S. This ridge is fitted between the coil 2 wound around one straight portion and the coil 2 wound around the other straight portion, and can be used for positioning the coil 2 in the case 3 it can. In addition, this protrusion causes the occurrence of locations where the sealing material is locally thickened in the vicinity of the corners where the coils face each other on the bottom side of the case, and the thickness of the sealing material is locally increased. It suppresses and it avoids that the location where a heat dissipation characteristic falls locally arises.

  When the coil 2 is formed on the core 1, an insulator 4 is interposed between the two to ensure insulation between the core 1 and the coil 2. The insulator 4 includes a cylindrical body portion (not shown) that covers the outer periphery of the core 1 and a plate-shaped collar portion 4F that comes into contact with the end portion of the coil 2. In this example, all were composed of polyphenylene sulfide (PPS). The trunk portion covers the outer periphery of the core 1 by engaging the half-cut square tube pieces. A plurality of slits are formed in the body portion so that the sealing material also enters between the body portion and the core 1. The collar portion 4F is a pair of rectangular frames that face both end portions of the body portion and abut against each end portion of the coil 2. A pair of rectangular holes through which each straight portion of the core 1 passes is formed in the collar portion 4F. The width of the collar portion 4F is considerably narrower than the inner width between the side surfaces of the case, and does not have a function of positioning the assembly of the core 1 and the coil 2 in the case.

<Reactor assembly procedure>
First, the normal block piece 1N and the gap portion 1G are joined (FIG. 2). Next, the insulator body is attached to the outer periphery of the joined body.

  On the other hand, a coil 2 configured by winding a winding is prepared. The coil 2 is fitted on the outer periphery of the trunk. Subsequently, the collar portion 4F is disposed at the end portion of the coil 2. The U-shaped block piece 1U penetrates the collar portion 4F, and the U-shaped block piece 1U is joined to the above-described joined body. In this state, an assembly in which the core 1 and the coil 2 are combined is configured.

  Next, the assembly is stored in the case 3. At that time, a spacer (not shown) is interposed between the coil 2 and the case 3 so that the distance between the both side surfaces 3S of the case 3 and the coil 2 becomes a predetermined value. Here, a plastic piece having a thickness of about 2.0 mm was used as a spacer.

  After that, the leaf spring 5 is disposed in the case housing portion 3R, pressed against one end of the core 1, and further the stopper 6 is screwed to the case 3 so that the leaf spring 5 does not fall off from the case 3 (see FIG. 3).

  Further, the stay 8 is disposed on the core 1 on the side opposite to the side where the leaf spring 5 is arranged, and is screwed to hold the core 1 (assembly) in the case 3 in a positioned state.

  When the assembly is completely attached to the case 3, the spacer is removed. This removal can be done simply by pulling out the spacer.

  When the above assembly is completed, the case 3 is filled with an epoxy resin sealing material. By this filling, the gap between the coil 2 and the case 3 is filled with a sealing material, and insulation between the coil 2 and the case 3 is ensured.

<Example of trial calculation>
In the reactor of Example 1 mentioned above and the conventional reactor shown in FIG. 8, when the case was cooled from the outside by the cooling mechanism, it was estimated how many times the highest temperature of the coil in the case would be.

  FIG. 4A shows a cross-sectional view of a conventional reactor. As shown in this figure, the reactor consists of the case 3, the outer sealing material 20-O (epoxy resin), the bobbin cover 10 (PPS), the inner sealing material 20-i (epoxy resin), the coil 2 in order from the outside. Insulator body 4C and core 1. Here, an enlarged cross-sectional view of the side portion of the reactor is shown in FIG. The thickness of each part in this enlarged sectional view is as follows.

Inner sealing material: 0.5mm
Bobbin cover: 3.5mm
Outer sealing material: 1.35mm

  In this reactor, when the case was water-cooled from the outside, the inner surface temperature of the case was assumed to be 65 ° C, and the ultimate temperature of the coil was estimated when the maximum operating voltage was 650V and 150A was energized. This trial calculation was based on the following formula to determine how much the temperature difference (ΔT) between the case and the coil would be when the maximum current was applied.

ΔT∝ (d / λ) Q
d: Heat dissipation path thickness (mm)
λ: Thermal conductivity (W / (m · k))
Q: Amount of heat passing through (200W)

  On the other hand, as shown in FIG. 5, the reactor of Example 1 is the above-described conventional reactor except that there is no bobbin cover between the coil 2 and the case 3 and the thickness of the sealing material 20 is changed. It is the same composition as. However, the thickness of the sealing material 20 was set to 2.0 mm in consideration of insulation.

  As a result of the trial calculation, in the conventional reactor, the total thickness of the inner sealing material and the outer sealing material was 1.85 mm, but the bobbin cover was 3.5 mm, so the ultimate temperature of the coil was 170 ° C. On the other hand, in the reactor of Example 1, although the thickness of the sealing material is 2.0 mm, since the bobbin cover does not exist, the reached temperature of the coil is 120 ° C., and the reached temperature can be reduced by about 50 ° C. I understood it. Moreover, since the epoxy resin has a withstand voltage characteristic with respect to the maximum usable voltage if it has a thickness of 2.0 mm, it was confirmed that there is no problem in terms of insulation. From these results, it can be seen that according to the reactor of the present embodiment, by not using the bobbin cover, the heat dissipation characteristics can be improved, the number of parts can be reduced, and the case can be downsized. Alternatively, if the case size is the same as that of the conventional case, the width of the assembly can be slightly increased, so that the winding of the coil can have a larger cross-sectional area, and a large current It can be expected to be a compatible reactor.

(Example 2)
Next, Example 2 will be described with reference to FIG. Since this example has the same configuration as that of the first embodiment except for the form of the collar portion 4F, the following description will focus on differences from the first embodiment.

  The collar portion of this example is wider than that of the first embodiment. The width of the collar portion 4F is such that the assembly having the core 1 and the coil 2 can be positioned in the case 3. Therefore, if the assembly is stored in the case 3, it is automatically The assembly can be positioned in the case 3. Therefore, according to the configuration of this example, the reactor can be assembled without using the spacer used in the first embodiment.

(Example 3)
Next, Example 3 will be described with reference to FIG. Since this example has the same configuration as that of the first embodiment except for the configuration of the inner surface of the case, the following description will focus on differences from the first embodiment.

  In this example, a thin film coating was formed at a predetermined location in the case 3. This thin film coating is made of aluminum nitride, which is insulating and excellent in thermal conductivity, and has a thickness of several tens to several hundreds μm. Further, as shown by hatching in FIG. 7, the locations where the thin film coating was formed were the surfaces of the side surfaces 3S and the bottom surface 3BB of the case inner surface. Since these portions are portions where the coils face each other when the assembly is stored in the case 3, if the thin film coating is present at these portions, sufficient insulation between the coils and the case 3 can be ensured. Moreover, the heat dissipation effect can be further enhanced by bringing the coil and the thin film coating as close as possible within a range in which insulation can be ensured.

  According to the configuration of this example, since the insulation between the coil and the case is insulated by the sealing material and the thin film coating, the reliability of insulation between the coil and the case can be improved without impairing the heat dissipation.

  The above-described embodiments are merely specific examples of the present invention, and it goes without saying that other various modifications can be made. For example, when the core / coil assembly is stored in the case, the outer periphery of the core (between the flanges) is covered with an insulating sheet, and the assembly is set at an appropriate position in the case. It is possible to prevent the coil insulation coating from being damaged when the assembly is housed by pulling it out.

  The present invention can be used as a reactor having excellent heat dissipation characteristics. In particular, it can be suitably used as a reactor for automobiles such as hybrid cars and electric cars.

1 core
1M Magnetic material part 1G Gap part 1N Normal block
1U U-shaped block piece
2 coils
3 cases
3S Side 3E End 3B Bottom 3BS Step 3BB Bottom 3R Storage
4 Insulator
4C trunk 4F collar
5 leaf spring
5T holding surface
6 Stopper
7 Screw
8 stays
9 Screw
10 Bobbin cover
20 Encapsulant 20-i Inner encapsulant 20-O Outer encapsulant

Claims (5)

A reactor comprising a core, a coil wound around the core, a case that houses the core on which the coil is formed, and a sealing material that seals the core and the coil in the case,
Between the case and the coil, there is no bobbin cover for aligning the core in which the coil is formed in the case,
Ensuring insulation between the coil and the case with the sealing material, the thickness of the sealing material between the coil and the case is 2.0 mm or more and 2.5 mm or less,
A stay for pressing the upper surface of the core exposed from the coil;
Furthermore, the outer periphery of the core includes an insulating collar portion that comes into contact with the end portion of the coil,
With this stay, while fixing the core to the case,
A reactor configured to align the core on which the coil is formed with the case by the collar portion.   The reactor according to claim 1, further comprising an insulating thin film coating on a portion of the case inner surface facing the coil.   The reactor according to claim 2, wherein the material of the thin film coating is at least one selected from aluminum nitride, boron nitride, silicon nitride, and silicon carbide. The core is supported in the case by bringing the portion not covered with the coil into contact with the inner surface of the case,
The space between the support surface of the core and the case bottom surface in the case is set so that a predetermined insulation distance can be secured between the case bottom surface and the coil in the support state of the core. The reactor as described in any one of. The core has two straight portions, and the coil is wound around both straight portions of the core,
The mountain-shaped protrusion which is inserted between the coil wound around one linear part and the coil wound around the other linear part is formed in the bottom of the case. The reactor as described in any one of 1-4.

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