JP2009253105A - Reactor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor device manufactured by cast-molding a mixture of a magnetic powder and a resin or the like, which suppresses a temperature rise in a coil by conducting copper loss heat to a metal case more efficiently than before. <P>SOLUTION: A reactor device comprises a case and a coil placed in the case and provided with an insulating coating, and is filled with a mixture of a magnetic powder, a ceramic powder, and a resin. The reactor device is characterized in that the coil is disposed so as to be adjacent only to the case bottom through an insulating sheet having high heat conductivity. The coil is preferably formed so that its circumferential side adjacent to the case is flat. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reactor device used in a power supply circuit. In particular, the present invention relates to a reactor device suitable for an in-vehicle use such as a hybrid vehicle or a power conditioner such as a solar power generation system.

  As a reactor manufacturing method, a coil-sealed resin-molded reactor having a structure in which a mixture of magnetic powder and resin is molded to surround a coil is known. For example, Patent Document 1 discloses a coil in which an insulation-coated coil is molded so as to be wrapped with a mixture of iron-based magnetic powder and epoxy-based resin. The characteristics of the reactor obtained by mixing the resin at a ratio of 4/6 to 1/9 with respect to the volume of the magnetic powder alone is twice the allowable current with respect to the inductance value compared to the conventional one. By using it, miniaturization is achieved compared to the conventional product.

  The hybrid vehicle described above has a high-output electric motor, and a power source circuit for driving the electric motor is required to have a reactor device that can withstand a large current. There is a strong demand for downsizing such a reactor device, and it is conceivable to reduce the size by the method of Patent Document 1 described above.

In the coil portion of the reactor device, a loss (copper loss) is generated by the product of the coil resistance and the square of the effective value of the current. Therefore, a large loss occurs at a large current. Practically, it is necessary to efficiently dissipate this large copper loss.
For example, Patent Document 2 discloses a reactor in which a coil that generates magnetic flux is impregnated in a magnetic powder mixed resin, and as a feature thereof, a technique for improving heat dissipation by forming a protrusion on the inner wall surface of a surrounding case. Is described.

Japanese Patent Application Laid-Open No. 5-291046 JP 2008-42094 A

Since the method of Patent Document 1 has an outer iron type structure in which the coil portion is embedded in the magnetic core portion, the copper heat loss generated in the coil portion is dissipated from the metal case through the magnetic core portion, but the thermal conductivity is low. The magnetic core portion made of a mixture containing a large amount of resin has poor heat conduction, and there is a drawback in that the copper heat loss spreads inside and the temperature rise of the coil portion becomes excessive.
Even in the configuration of Patent Document 2, the thermal conductivity is insufficient and there is room for study.
Therefore, an object of the present invention is to provide a reactor device that suppresses a rise in coil temperature by conducting copper loss heat more efficiently to a metal case than a conventional case as a reactor device that is manufactured by casting a mixture of magnetic powder and resin. It is to be.

  The present invention is a reactor device filled with a case, a single coil provided with an insulating coating disposed in the case, and a mixture containing magnetic powder, ceramic powder, and resin, wherein the coil has a high heat It arrange | positions so that it may adjoin only to the bottom part of a case through the insulating sheet which has electroconductivity.

  It is preferable that the coil is formed so that the peripheral side surface of the coil adjacent to the case is flat.

According to the present invention, since the bottom part of the coil component is in thermal contact with the bottom of the metal case (or external radiator) via the insulating sheet having a high thermal conductivity, the copper heat loss of the coil part is reduced. Heat is dissipated efficiently. Moreover, since it contacts a metal case via a highly heat-conductive insulating sheet, the insulation coating of a coil component is not peeled off by sliding with the case, and the reactor characteristics can be prevented from aged over time. Further, since the peripheral side surface of the coil component is flattened, the area adjacent to the case is large and the cooling performance is high.
Accordingly, it is possible to obtain a highly reliable reactor device in which the temperature rise of the coil is suppressed even at a large current. The present invention is particularly useful as a reactor device for a vehicle or a power conditioner.

The reactor device of the present invention is manufactured by a manufacturing method called casting molding. Casting molding is the installation of a coil component in a case, and magnetic powder, ceramic powder, resin, etc. are placed between the coil component and the case. This is a technique for pouring and integrating a slurry-like mixture. The poured mixture is also filled in the inner diameter portion of the coil, and becomes a magnetic path when a current is passed through the coil.
Although it is not necessary to pressurize when pouring, the space factor of the mixture in the case can be increased by applying pressure after casting the mixture.
Moreover, since the mixture is filled without gaps between the coil windings in cast molding, a reactor device in which the coil is firmly fixed and held can be manufactured.

Magnetic powder is, for example, pure iron powder, Fe-Si alloy powder, Fe-Al alloy powder, Fe-Si-Al alloy powder, Fe-Ni alloy powder, Fe-Co alloy powder, amorphous soft magnetic powder, nanocrystalline These are soft magnetic powders, and these may be used alone or in combination as appropriate.
The shape of the magnetic powder is not particularly limited, and may be flat or spherical. Using spherical magnetic powder makes it easier to increase the space factor of the magnetic powder in the case and to improve the reactor characteristics. The spherical magnetic powder can be manufactured by using a known manufacturing method such as water atomization, gas atomization, or SWAP.
Moreover, the space factor of the magnetic powder in a case can also be mentioned using the mixed powder of spherical powder and flat powder, or the mixed powder of a powder from which particle size distribution differs.

  As the high thermal conductive ceramic powder, silica, magnesia, kaolin, talc, aluminum nitride, silicon nitride, titania, zirconium and the like are used in addition to alumina. In particular, alumina has a high thermal conductivity and has an advantage that it is advantageous for heat radiation of the reactor. These may be used alone or in combination as appropriate.

As the resin, the surface of the magnetic powder is coated so that the powders are insulated from each other, and a sufficiently large electric resistance is applied so as to suppress the generation of eddy currents with respect to the AC magnetization of the entire magnetic core, and at the same time, the powders are bonded. It functions as a binder to be attached and can function as an insulator in a state mixed with magnetic powder. As such a resin, for example, various resins such as an epoxy resin, a polyamide resin, a polyimide resin, a polyester resin, and a silicon resin are used, and these may be used alone or in appropriate combination.
In consideration of the environment in which the reactor apparatus is used, it is preferable to use a thermosetting resin, but a photocurable resin, a chemically reactive curable resin, or the like may be used.

  As shown in FIG. 3, since the coil uses a wire rod having a substantially rectangular cross-sectional shape called a rectangular conductor, the contact area between the coil 12 and the high thermal conductive sheet 11 is increased, and copper heat loss is efficiently radiated. The When a general wire having a round cross-sectional shape is used, the contact area between the coil 12 and the high thermal conductive sheet 11 is small, so the heat dissipation of copper heat loss is inferior to that of a flat wire.

In order to give the reactor device heat dissipation, it is preferable that the case has excellent heat conductivity and heat transfer. For example, a light alloy such as an aluminum alloy or a ceramic such as alumina can be used.
In the reactor device, magnetostriction is periodically generated by an alternating current, and its vibration becomes a problem. In addition, when used in automobile applications, it is necessary to use a material that can withstand a high temperature environment. Therefore, it is necessary to select materials as appropriate according to the environment in which they are applied.

The manufacturing process of the reactor device 20 of the present invention will be described with reference to FIGS. FIG. 2 shows a metal case 10 made of aluminum. The shape of this case varies depending on the use of the reactor device. For in-vehicle use, the reactor element body is cooled by water-cooling a part of the case or by coupling to a water-cooled cooling device. A high thermal conductive sheet 11 is attached to the inner bottom surface of the metal case 10. As the high thermal conductive sheet 11, for example, a flexible silicon sheet manufactured by Denki Kagaku Kogyo Co., Ltd. or a graphite sheet with an insulating property manufactured by Matsushita Electric Industrial Co., Ltd. is used. The thickness of the high thermal conductive sheet 11 is from 0.1 mm to 3 mm. Next, the coil 21 with the insulating coating shown in FIG. 3 is installed in accordance with the position where the high thermal conductive sheet 11 is attached. In addition, the coil 21 is installed in a central portion away from the side surface of the case 10 with the axis facing sideways.
Next, as shown in FIG. 4, a mixture 13 of magnetic powder, high thermal conductive ceramic powder, and resin is poured into the metal case 10. At this time, since the mixture 13 is filled up to the gap between the conductors of the coil 21, the fixing and holding of the coil 21 is further strengthened. The ends of the coil wires are extended upward to form electrode terminals 12. FIG. 1 shows a state in which the mixture 13 has hardened and the reactor device 20 of the present invention is completed.
The magnetic path is in a Kanji day shape consisting of the mixture 13 filled in the coil 21 and the mixture 13 filled between the coil 21 and the case 10.

It is the schematic of the reactor apparatus of the Example of this invention. It is the figure which looked at the recessed part of the metal case which concerns on this invention from the top. It is a perspective view which shows the coil which concerns on this invention. It is a figure explaining injection | pouring of the mixture which concerns on this invention.

Explanation of symbols

20: Reactor device, 10: Metal case, 11: High heat conduction sheet, 12: Electrode terminal, 13: Mixture, 21: Coil

Claims (2)

A reactor device filled with a case, a single coil with an insulating coating disposed in the case, and a mixture containing magnetic powder, ceramic powder, and resin, the coil having high thermal conductivity A reactor device, wherein the reactor device is disposed so as to be adjacent to only a bottom portion of a case through an insulating sheet. The reactor device according to claim 1, wherein the coil is formed in a flat shape on a peripheral side surface of the coil adjacent to the case.

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