JP2017028199A - Reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor which prevents heat radiation from a sealing resin body serving as a heat radiation member to a cooler from being hindered even when a core and a coil repeats heat expansion and heat shrinkage during operation of the reactor and thus maintains good heat radiation performance.SOLUTION: A reactor 10 includes: a case 4; a core 1 including a coil 2 disposed in the case 4; a sealing resin body 5 which closes a space between the case 4 and the core 1 and has heat radiation capability; and a cooler 6 disposed below the case 4 and to which a refrigerant R flows back. An opening 4b is formed at a bottom surface 4a of the case 4, and the refrigerant R flows back while contacting with the sealing resin body 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reactor.

  More specifically, a reactor is applied as a component of a power conversion device such as an in-vehicle DC-DC converter, as a circuit component that performs voltage step-up or step-down control in the power conversion device.

  As a general configuration of the reactor, a U-shaped core and an I-shaped core are assembled in a ring shape through a gap (a gap plate is connected to the core with an adhesive), and a coil is formed around it. A sealed resin body that is housed and has a heat dissipation property between the core or coil and the bottom surface of the case is molded, and a cooler is disposed below the case. Further, this type of reactor is disclosed in Patent Document 1.

  By the way, the core or coil that is a heat source during the operation of the reactor repeats thermal expansion and thermal contraction, and this repeated thermal expansion and thermal contraction is molded between the core or coil and the bottom of the case. It acts on the resin body and may be a factor for inhibiting heat dissipation. This will be described with reference to FIGS.

  FIG. 6 shows a reactor having a conventional structure. In the illustrated reactor RT, a core Co in which a coil Ci is disposed is fastened to a case Ca with a bolt B via a stay S, and a sealing material that is a heat dissipation material is interposed between the core Co, the coil Ci, and the bottom surface of the case Ca. A stop resin body Re is molded, and a cooler Cl through which the refrigerant R circulates is disposed below the case Ca to constitute the whole.

  When the reactor RT is operated, the coil Ci that is a heat generation source is thermally expanded as shown in FIG. 7A (Y1 direction), and then is thermally contracted as shown in FIG. 7B (Y2 direction). This thermal expansion and thermal contraction are repeated.

  By repeating the thermal expansion and contraction of the coil Ci, the sealing resin body Re is pulled by the movement of the coil Ci, and the adhesive strength at the interface between the bottom surface of the case Ca and the sealing resin body Re is gradually weakened. As shown in FIG. 7C, there is a possibility that the interfacial peeling occurs and the gap G is formed.

  Thus, when the interface between the sealing resin body Re and the bottom surface of the case Ca is peeled off, the restoration is not performed, and the heat dissipation from the sealing resin body Re, which is a heat radiating member, to the cooler Cl is caused by the gap G. The heat dissipation performance (cooling performance) of the reactor RT is deteriorated.

JP 2012-256722 A

  The present invention has been made in view of the problems described above, and even when the core and the coil repeat thermal expansion and thermal contraction during the operation of the reactor, heat dissipation from the sealing resin body, which is a heat dissipation member, to the cooler is hindered. An object of the present invention is to provide a reactor that is capable of maintaining good heat dissipation performance.

  In order to achieve the above object, a reactor according to the present invention includes a case, a core including a coil disposed in the case, a sealing resin body having a heat dissipation property that closes the space between the case, and a lower portion of the case. The reactor is provided with a cooler that circulates the refrigerant, and has an opening in the bottom surface of the case, and the refrigerant circulates in contact with the sealing resin body.

  The reactor of the present invention has an opening in the bottom surface of the case that accommodates the coil and the core, and the refrigerant that circulates through the cooler disposed below the bottom surface is in contact with the sealing resin body that is a heat dissipation member through the opening. It has the characteristic in being. With this configuration, since there is no contact interface with the sealing resin body at the opening on the bottom surface of the case, even when the coil or the like is thermally expanded or contracted, peeling between the case and the sealing resin body cannot occur. Furthermore, since the sealing resin body is in direct contact with the refrigerant, good heat dissipation performance can be maintained.

  Here, the sealing resin body having heat dissipation can be formed from a silicone resin, an epoxy resin, or the like, and a thermally conductive filler such as silica or aluminum may be dispersed in such a resin material.

  Further, cooling water or cooling air from a radiator or the like can be applied as the refrigerant that circulates through the flow path formed in the cooler.

  Here, the sealing resin body may have a fin projecting downward, and the fin can enter the refrigerant of the cooler to further enhance the heat dissipation effect. The fins are preferably formed integrally with the sealing resin body.

  According to the reactor of the present invention, an opening is formed in the bottom surface of the case, and the sealing resin body and the refrigerant circulating in the cooler are in contact with each other. And it is possible to maintain this heat dissipation performance.

  As can be understood from the above description, according to the reactor of the present invention, an opening is established in the bottom surface of the case constituting the reactor, and the refrigerant is refluxed while being in contact with the sealing resin body. Excellent heat dissipation performance can be maintained.

It is a longitudinal cross-sectional view of Embodiment 1 of the reactor of this invention. It is a longitudinal cross-sectional view of Embodiment 2 of the reactor of this invention. It is a figure explaining the manufacturing method of a reactor. It is the figure explaining the manufacturing method of the reactor following FIG. It is the figure explaining the manufacturing method of the reactor following FIG. It is a longitudinal cross-sectional view of embodiment of the conventional reactor. (A) is the figure explaining the state which the coil expanded thermally, (b) is the figure explaining the state which the coil thermally contracted, (c) is the interface of the sealing resin body and the bottom face of a case peeling It is a figure explaining the state which carried out.

  Hereinafter, embodiments of a reactor of the present invention will be described with reference to the drawings. In the illustrated example, the upper part of the core and the coil is exposed to the outside air, but the sealing resin body may completely seal the upper region of the core and the coil.

(Embodiment 1 of the reactor)
FIG. 1 is a longitudinal sectional view of a reactor according to a first embodiment of the present invention. The illustrated reactor 10 includes a case 4, a core 1 having a coil 2 disposed in the case 4, and a sealing resin body 5 having a heat dissipation property that closes between the case 4, the core 1, and the coil 2. The cooler 6 is arranged below the case 4 and the refrigerant R is recirculated. Here, the core 1 is fastened to the case 4 via a stay 3 with bolts 3a.

The core 1 has a U-shaped core and an I-shaped core formed in a substantially ring shape via a gap plate (not shown), and is made of a resin, soft magnetic powder, and the like. Here, as the soft magnetic powder, iron group metals such as Fe, Co, and Ni, alloy powders containing iron as a main component, and the like can be applied. In particular, Fe-Si alloys, Fe-Ni alloys, Fe-Al alloys, Fe-Co alloys, Fe-Cr alloys, Fe-Si-Al alloys, rare earth metals, ferrites, and the like can be applied. On the other hand, the resin may be either a thermosetting resin or a thermoplastic resin, but it is preferable to apply a thermoplastic resin that can eliminate the need for a curing furnace and can be injection-molded to reduce manufacturing time. . Examples of the thermoplastic resin to be applied include polyamide, polyester, polyphenylene sulfide, polyether ether ketone, polyethylene, polypropylene, methacryl, and polyimide resin. The gap plate can be formed of ceramics such as alumina (AL ₂ O ₃ ) or zirconia (ZrO ₂ ). If the electromagnetic characteristics of the reactor, that is, the inductance can be ensured with the structure without the gap plate, the interposition of the gap plate between the cores is unnecessary.

  The coil 2 is composed of a copper conducting wire and an insulating coating such as an enamel coating formed around the conducting wire, and a rectangular wire with a high space factor is suitable.

  The case 4 is made of aluminum or an alloy thereof, and has an opening 4b on the bottom surface 4a.

  The cooler 6 has a flow path formed therein, and cools the heat transferred by the refrigerant R flowing back through the flow path. Here, as the refrigerant R, cooling water or cooling air from a radiator or the like can be applied.

  The sealing resin body 5 is a material based on a silicone resin, an epoxy resin, a urethane resin or the like as long as it is a moisture curable type or a room temperature curable type (which may be a one-component type or a two-component mixed type). Formed from.

  Here, the silicone resin will be further described. This silicone resin (silicone polymer) has a siloxane bond structure in which a polymer is formed by alternately bonding silicon and oxygen as a main skeleton. Depending on the presence or absence and type of these additives, there are sheet-like, paste-like, and liquid ones. As the silicone forming the sealing resin body, paste-like or liquid silicone can be used. In addition, although the thermal conductivity of the silicone polymer itself is as small as 0.16 W / mK, it can be mixed by mixing thermal conductive fillers such as silica, alumina, boron nitride, silicon nitride, silicon carbide, and magnesium oxide. Since it becomes silicone which has high heat dissipation according to quantity (mixing ratio), it is preferable to use the resin material containing the appropriate filler so that desired heat dissipation may be satisfied.

For example, a sealing resin body 5 having physical properties of thermal conductivity λ ≧ 0.5 W / mK, insulation (volume resistivity) ≧ 10 ¹² Ωcm, and initial hardness (durometer Type A) ≦ 85 can be applied.

  Since the opening 4b is opened on the bottom surface 4a of the case 4, the sealing resin body 5 directly faces the lower cooler 6, and the refrigerant R flowing back through the flow path of the cooler 6 is used as the sealing resin body 5. Reflux while touching.

  Thus, since the sealing resin body 5 which is a heat radiating member is in direct contact with the refrigerant R, the heat from the heat source such as the core 1 and the coil 2 is effectively passed through the sealing resin body 5 to effectively cool the cooler 6. Therefore, the reactor 10 is excellent in heat dissipation performance (cooling performance).

  Further, unlike the conventional reactor RT shown in FIG. 6, since there is no contact interface with the sealing resin body 5 in the opening 4b of the bottom surface 4a of the case 4, even when the coil 2 or the like is thermally expanded or contracted. Peeling between the case 4 and the sealing resin body 5 cannot occur, and there is no problem that heat release from the sealing resin body 5 to the cooler 6 is hindered by such peeling.

(Embodiment 2 of the reactor)
FIG. 2 is a longitudinal sectional view of a reactor according to a second embodiment of the present invention. Although the illustrated reactor 10A has the same basic configuration as the reactor 10, the fin 5a made of the same material as the sealing resin body 5 projects below the sealing resin body 5 and enters the refrigerant R. It has characteristics.

  Since a large number of fins 5a continuous with the sealing resin body 5 face the refrigerant R, the reactor 10A having higher heat dissipation performance is obtained.

(Reactor manufacturing method)
3-5 is the figure explaining the manufacturing method of the reactor 10 in the order.

  First, as shown in FIG. 3, the core 1 provided with the coil 2 is bolted to the case 4 via the stay 3 to produce an intermediate.

  An opening 4b is formed in the bottom surface 4a of the case 4. A forming die M having a convex portion Ma that fits into the opening 4b is prepared, and the opening 4b is fitted into the convex portion Ma (X1 direction). An intermediate is installed in M.

  Next, as shown in FIG. 4, a resin material for molding a sealing resin body is molded in the space between the core 1 and the coil 2, the case 4, and the convex portion Ma of the mold M, and waits for the resin material to harden. Thus, the sealing resin body 5 is molded.

  When the sealing resin body 5 is molded, the reactor intermediate body is manufactured by removing the reactor intermediate body from the mold M (X2 direction) and finally connecting the intermediate body and the cooler 6 as shown in FIG. Is done.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Core, 2 ... Coil, 3 ... Stay, 3a ... Bolt, 4 ... Case, 4a ... Bottom surface, 4b ... Opening, 5 ... Sealing resin body, 5a ... Fin, 6 ... Cooler, 10, 10A ... Reactor, R: Refrigerant

Claims (1)

Case and
A core comprising a coil disposed in the case;
A sealing resin body having a heat dissipation property to block between the case and the core;
A reactor that is disposed under the case and in which a refrigerant recirculates, and a reactor,
The reactor has an opening in the bottom of the case, and the refrigerant is refluxed while in contact with the sealing resin body.

Images