JP2011086657A - Reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor excellent in heat dissipation performance and enabling a higher current to be supplied without requiring increase in the size of the reactor, by providing a reactor having a structure for directly or actively cooling at least a coil which is a heat source while effectively using magnetic flux flowing in the reactor. <P>SOLUTION: The reactor 10 is obtained by forming a reactor core which is substantially annular in plan view and forms a first magnetic flux passage, and forming first and second coils 4a and 4b respectively in a first core region 1a and a second core region 1b, opposite each other, of the reactor core. In the reactor 10, a second magnetic flux passage is formed between a third core region 1c and a fourth core region 1d connecting the first core region 1a and second core region 1b, the second magnetic flux passage is provided with: a rotor 7 which has a coil therein and scatters a supplied cooling medium to the periphery; and magnets 6a and 6b for defining a flow direction of magnetic flux flowing in the second magnetic flux passage. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reactor constituting a power conversion circuit.

  The reactor of the power conversion circuit is generally housed in, for example, a housing (case) in a posture in which a coil is formed in two longitudinal portions of a reactor ring that is generally horizontally long in plan view. This reactor core is composed of a laminate of a plurality of magnetic steel sheets or a split core consisting of dust cores, and a gap plate made of a non-magnetic material is interposed between each split core. A reactor core is formed by being bonded and fixed with an adhesive.

  For example, a heat radiating plate (heat sink) is provided on the lower surface (bottom surface) of this housing, and a cooler that circulates cooling water or air may be provided below the heat sink. Joule heat generated when the coil is energized In one embodiment, there is a structure in which the coil or the reactor is released to the outside through the heat sink, for example, via a cooler. Here, in a reactor having a case, a resin may be potted between the case and the reactor housed in the case to form a mold resin body. Heat is dissipated to the outside or to the heat sink through the body.

  In recent years, in reactors mounted on hybrid vehicles, electric vehicles, etc., the current value that is passed through the reactor with a small physique has increased as much as possible, and how to effectively dissipate the increasing calorific value However, it is one of the important solutions in this field.

  Here, the following public technique can be mentioned as the conventional public technique proposed for the purpose of improving the heat dissipation performance. One of them is that a fan is built in the motor and cooling is performed by forcibly applying wind to the reactor. Patent Document 1 discloses the technology. However, in the reactor of this structure, it is necessary to prepare a motor for the reactor torque ring separately, and in the current automobile industry, etc., which are trying to reduce the weight and size of the vehicle and the number of components of the mounted equipment, It is a reactor that is difficult to adopt.

  On the other hand, in Patent Document 2, a reactor is placed directly on a heat sink, and the heat generated by the coil is radiated through the heat sink. Many other reactors having such a structure have been proposed and disclosed. Yes. When referring to this reactor, in the structure that expects heat dissipation action to the heat sink outside the reactor as described above, the reactor core itself including the coil that is actually the heat source is not directly cooled, It is difficult to obtain a large heat dissipation effect. Therefore, in order to fully expect the heat dissipation effect, it is necessary to expect a proposal of a technique for directly or actively cooling the reactor core itself by some means.

  Further, Patent Document 3 discloses a reactor having a structure in which a cooling pipe is built between a coil wound around a reactor core and a core. In this structure, a relatively high reactor cooling effect (heat dissipation effect) can be expected as compared to a technology that expects an external heat sink to dissipate heat. However, in order to cool as desired, it is necessary to incorporate a pipe with a certain diameter, and for this reason, it is easy to understand that the size of the reactor itself must be large.

JP-A-2-246675 JP 2005-286020 A JP 2008-186904 A

  The present invention provides a reactor having a structure capable of directly or actively cooling at least a coil as a heat source while effectively utilizing magnetic flux flowing in the reactor without increasing its physique. An object of the present invention is to provide a reactor that is excellent in heat dissipation performance and that can be energized with a higher current.

  In order to achieve the above object, a reactor according to the present invention includes a reactor core in which a plurality of magnetic cores are connected via an insulating portion to form a first magnetic flux channel having a substantially annular shape in plan view. A reactor in which first and second coils are respectively formed in opposing first and second core regions of a core, wherein the first core region and the second of the reactor cores The second magnetic flux channel is formed between the third core region and the fourth core region, and the second magnetic flux channel has a coil therein, A rotor for spreading the provided cooling medium around and a magnet for defining the flow direction of the magnetic flux flowing through the second magnetic flux flow path are provided.

  In the reactor constituting the reactor of the present invention, for example, two U-shaped magnetic cores in a plan view form a substantially ring shape through a gap layer such as a gap plate, and coils are formed in two opposing core regions. In this case, a separate magnetic flux flow path in which a part of the magnetic flux flowing through the reactor core is provided in the annular reactor core, and a rotatable rotor is disposed in the flow path. The rotor is rotated using the flowing magnetic flux, an appropriate cooling medium is provided to the rotor, and the cooling medium is dispersed around the coil by the rotation of the rotor, thereby directly cooling the coil as a heat source. It is the reactor comprised so that.

  Even if the reactor has a separate magnetic flux flow path (second magnetic flux flow path) equipped with a rotor, the reactor can effectively utilize the originally unused space inside the annular reactor core. There is no need to increase the physique.

  Note that the U-shaped core that forms the reactor core, the cardinal number of the I-shaped core (rectangular core) in plan view, the form of the gap layer, and the like are not particularly limited, and the reactor core that includes only two U-shaped cores, The two U-shaped cores and the reactor core with one or more I-shaped cores interposed between these two core ends can be used. The gap layer is also made of a non-magnetic material only. , A form formed from a non-magnetic material gap plate and an adhesive, a form formed by thermocompression bonding a non-magnetic material resin sheet to both cores, and the like.

  The rotor interposed in the second magnetic flux passage does not need to be a rotor formed by laminating electromagnetic steel plates, for example, as in a general motor rotor, and the formation material thereof is arbitrary, and a laminate of various steel plates. , Powder cores, cast iron and the like formed integrally.

  In this rotor, for example, a coil is embedded, and this coil is connected to, for example, a switching power source. An alternating current that switches the energization direction at a desired timing is supplied to the coil, When the magnetic flux flowing through the second magnetic flux passage passes through the coil, the force generated based on Fleming's law excites the rotation of the rotor.

  In this rotor, a flow path through which a cooling medium such as cold water and cooling oil flows is defined. For example, a part of the cooling medium provided to the cooling medium refluxer constituting the reactor device is provided to this rotor. Then, the cooling medium is dispersed around the rotor through the flow path in the rotor, for example, through an opening formed on the side surface of the rotor. In particular, the rotation efficiency of the rotor is improved by the rotation of the rotor, and the cooling medium is provided directly to the coil, particularly the outer periphery of the rotor, so that the coil serving as the heat source can be effectively cooled.

  Moreover, the magnet for prescribing | regulating the flow direction of the magnetic flux which flows here is interposed in the 2nd magnetic flux flow path.

  If the amount of magnetic flux flowing through the second magnetic flux flow path is too large, the inductance performance that is the original performance of the reactor is hindered. Therefore, the flow direction of the magnetic flux in the second magnetic flux flow path is uniquely determined. In addition, a magnet having a desired radix is disposed at a predetermined position of the second magnetic flux passage so that the amount of magnetic flux is controlled so that the amount of magnetic flux is sufficient to rotate the rotor.

  For example, the magnet described above is arranged in a region of the second magnetic flux flow path that is downstream of the magnetic flux flow and in which the magnetic flux flowing through the second magnetic flux flow path merges with the first magnetic flux flow path, The magnet can be configured to prevent the flow of magnetic flux from the first magnetic flux flow path to the downstream side of the second magnetic flux flow path.

  In this form, one or a plurality of magnets can be arranged on the downstream side described above. For example, in the form in which two magnets are arranged at intervals, in order to define the flow direction of magnetic flux in one direction, Both are preferably arranged in the same NS direction.

  Further, it is desirable that a magnet is not provided on the upstream side of the second magnetic flux channel. This is because by providing a magnet on the upstream side, an excessive magnetic flux may be drawn into the second magnetic flux channel, and the magnetic flux that flows through the first magnetic flux channel and contributes to the inductance can be inhibited.

  Therefore, the core material forming the second magnetic flux flow path is preferably formed of a material having a higher magnetic resistance than the magnetic core forming the first magnetic flux flow path, for example. It is preferable that adjustment is made so that excessive magnetic flux does not flow into the second magnetic flux channel by forming the core material that constitutes the first and second magnetic flux channels with the material to be used.

  In a preferred embodiment of the reactor according to the present invention, a mold resin body is formed at least around the coil and in a region not facing the rotor while the rotor maintains a rotatable posture. It is.

  In order to ensure that the cooling medium sprayed from the rotating rotor is provided directly to the coil, a mold resin body is not formed in the coil area facing the rotor, and in the coil area where the cooling medium is not provided directly. In order to improve the heat dissipation from the coil region, for example, a molded resin body having good heat dissipation is formed.

  Note that this mold resin body is a reactor region other than the side facing the rotor of the coil, and the entire region or a part of the region in which the rotation of the rotor is ensured, that is, the outer periphery of each magnetic core or its Part of the outer periphery of the coil or part thereof can be molded, and therefore the final form of the reactor can be various.

  As can be understood from the above description, according to the reactor of the present invention, the desired inductance performance is ensured without increasing the physique, and a part of the magnetic flux flow is effectively used and disposed inside the reactor. By rotating the rotor and spraying the cooling medium directly on the coil that is a heat source, the reactor can be a reactor whose heat radiation performance is remarkably improved as compared with the reactor of the conventional structure.

It is a cross-sectional view of one embodiment of the reactor of the present invention. It is an enlarged view of the II section of FIG. It is the III-III arrow line view of FIG. It is a cross-sectional view of other embodiment of the reactor of this invention. It is the analysis result which compared the heat dissipation of both the reactor of this invention, and the reactor of the conventional structure.

  Embodiments of the present invention will be described below with reference to the drawings. The illustrated example shows a reactor core composed of two U-shaped cores, but a configuration composed of two U-shaped cores and two I-shaped cores, composed of two U-shaped cores and four or more I-shaped cores. Of course, it may be a form. In addition, the illustrated reactor may be a caseless form that is not accommodated in the case or may be accommodated in the case. In any of these forms, the heat sink plate is further provided below the form. The final form, such as a form in which a refrigerant reflux or the like is further provided below the heat sink plate, can be selected as appropriate.

  FIG. 1 is a cross-sectional view of the reactor according to the present invention cut at an intermediate position in the height direction, FIG. 2 is an enlarged view of a portion II in FIG. 1, and FIG. 3 is a view taken in the direction of arrows III-III in FIG. . The reactor 10 is entirely composed of two magnetic U-shaped cores 1 and 1 disposed at a predetermined distance, and a gap layer 2 and 2 having a predetermined width provided between these end portions. The first magnetic flux passage (this magnetic flux flow is a magnetic flux: G1) having a substantially annular shape (in the illustrated example, a substantially rectangular frame shape) is formed. And the 1st coil 4a and the 2nd coil 4b are formed in the 1st core area | region 1a and the 2nd core area | region 1b which face each other via the bobbins 3 and 3 which consist of an insulating material, Furthermore, this A second composed of rectangular cores 5 and 5 that connect the first core region 1a and the second core region 1b and in which the rotor 7 is interposed between the third core region 1c and the fourth core region 1d. The magnetic flux flow path (this magnetic flux flow is magnetic flux: G2) is formed, and the whole is roughly configured.

  Both the U-shaped core 1 and the rectangular core 5 are composed of magnetic cores that ensure the flow of magnetic flux, but in order to prevent the excessive magnetic flux from flowing into the second magnetic flux flow path in order to ensure the desired inductance performance, In particular, it is preferable to adjust both magnetic materials so that the magnetic characteristics of the U-shaped core 1 are improved, that is, the magnetic resistance of the rectangular core is increased.

  This magnetic core may be formed from a laminate formed by laminating silicon steel plates, and from a powder magnetic core formed by press-molding a soft magnetic metal powder or a magnetic powder coated with a soft magnetic metal powder with a resin binder. It may be formed. As the soft magnetic metal powder, iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy, iron-boron alloy, iron-cobalt alloy, iron- Phosphorus alloys, iron-nickel-cobalt alloys, iron-aluminum-silicon alloys, and the like can be used. As the soft magnetic metal oxide powder, ferrites such as manganese, nickel, and magnesium can be used.

The gap layer 2 is formed only from a non-magnetic adhesive, formed from a non-magnetic gap plate and an adhesive, or formed by thermocompression bonding a non-magnetic resin sheet to both cores. In the case of using a gap plate, ceramics whose main component is a metal such as Mg, Al, Si, Ti, Zr, such as alumina (Al ₂ O ₃ ) And zirconia (ZrO ₂ ) and other ceramics.

  When using a resin sheet for the gap layer, use a sheet made of a thermosetting resin such as epoxy resin, silicone resin, polyimide resin, polyurethane, unsaturated polyester, melamine resin, phenol resin, alkyd resin, etc. be able to.

  The rotor 7 interposed in the second magnetic flux channel can be formed from, for example, a steel plate laminate formed by laminating steel plates such as electromagnetic steel plates, a unit formed by integrally molding a dust core, cast iron, and the like.

  A coil (not shown) is embedded in the rotor 7, and a switching power supply (not shown) is connected to the coil so that the direction of energization is switched at a desired timing. Yes.

  When the reactor 10 is driven and the magnetic flux G1 flows through the first magnetic flux passage, a part of the magnetic flux G1 flows into the second magnetic flux passage in the middle of the flow, and the magnetic flux G2 passes through the rotor 7. Is formed.

  When a current is passed through the coil in the rotor 7 and the magnetic flux G2 passes through the coil, a force to rotate the rotor 7 is generated based on Fleming's law. As a result, continuous rotation of the rotor 7 while the reactor 10 is driven (X direction in FIGS. 1 and 2) is guaranteed.

  As shown in FIG. 3, the rotor 7 can rotate around a rotation shaft 7 d that is pivotally pivoted in a case (not shown). Furthermore, a cooling medium flow path 8 is provided for supplying a cooling medium such as cold water and cooling oil from the storage tank to the rotor 7, and the cooling medium flow path 8 is in fluid communication with the cooling medium flow path 8. A main flow path 7 a for circulating the cooling medium and a branch flow path 7 b branched from the main flow path 7 a and leading to an opening 7 c opened on the side of the rotor 7 are opened inside the rotor 7.

  When the cooling medium is provided to the rotor 7 via the cooling medium flow path 8 in the posture in which the rotor 7 rotates (Y direction in FIG. 3), the cooling medium passes through the side opening 7 c of the rotor 7 and the outer periphery thereof. Sprayed on.

  As is clear from FIG. 1, the coils 4a and 4b, which are the heat sources of the reactor 10, are arranged on the outer periphery of the rotor 7, so that the cooling medium is directly (actively) provided to the coils 4a and 4b. Provided, the coils 4a and 4b can be effectively cooled.

  Here, as described above, the magnetic path length, the flow of magnetic flux, or the amount of magnetic flux in the first magnetic flux flow path are extremely important elements for the inductance performance of the reactor 10. In order to secure a desired amount of magnetic flux in the first magnetic flux passage, adjustment of the amount of magnetic flux flowing into the second magnetic flux passage and adjustment of the flow direction of the magnetic flux are indispensable.

  Therefore, in the reactor 10 of the present invention, in one rectangular core 5 that forms the second magnetic flux flow path, two magnets 6a and 6b are arranged at an interval, and the other rectangular core 5 is embedded with a magnet. The form which does not do is applied.

  With this configuration, the magnet 6a embedded in one rectangular core 5 completely prevents the flow of the magnetic flux G1 (prevents the flow of the magnetic flux FG in FIG. 2), and only the flow of the magnetic flux from the other rectangular core 5. Can be invited. Further, as described above, the rectangular core 5 having a higher magnetic resistance than the U-shaped core 1 is disposed, and the magnet is not disposed on the upstream rectangular core 5. It is ensured that no excessive magnetic flux is drawn from the magnetic flux G1 into the magnetic flux flow path.

  The two magnets 6a and 6b are arranged from the rotor 7 side to S-N and S-N so that both NS poles ensure the flow direction of the magnetic flux G2, and flow out of the second magnetic flux flow path. The magnetic flux merges with the magnetic flux G1 flowing through the first magnetic flux flow path.

  In this way, by arranging the magnets at appropriate positions of the rectangular core 5 that forms the second magnetic flux channel, the amount of magnetic flux flowing through the first magnetic flux channel that determines the inductance performance of the reactor can be adjusted as desired. The flow direction of the magnetic flux flowing through the second magnetic flux passage for rotating the rotor can be uniquely defined. The number of magnets arranged in the rectangular core is not limited to the illustrated example, but may be a form in which one magnet is arranged, a form in which three or more magnets are arranged at intervals, and the like. Good.

FIG. 4 is a cross-sectional view of another embodiment of the reactor of the present invention.
The difference between the reactor 10A shown in the figure and the reactor 10 shown in FIG. 1 is that the reactor 10A includes the molded resin bodies 9 and 9 in the coil outer peripheral region other than the side surface facing the rotor 7 of the coils 4a and 4b. This is the point.

  This mold resin body 9 is made of epoxy resin, silicone resin, polyester resin, polyolefin resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT) in order to ensure good heat dissipation. Molded from any one or a mixture of these materials, or a material in which a filler such as silica, alumina, boron nitride, silicon nitride, silicon carbide, magnesium oxide, or glass fiber is further mixed with these resin materials. be able to.

  According to the reactor 10A, the cooling medium sprayed from the rotating rotor 7 is directly provided to the coils 4a and 4b, and the coil area where the cooling medium is not directly provided is provided to improve the heat dissipation performance from the coil area. Since the mold resin body 9 is formed, the reactor has a higher heat dissipation performance.

  In addition to the illustrated example, the molded resin body to be molded may be formed integrally with the outer periphery of the U-shaped core 1 in addition to the coils 4a and 4b.

[Analysis comparing the heat dissipation of both the reactor of the present invention and the reactor of the conventional structure, and the results]
In order to demonstrate that the heat dissipation performance of the reactor of the present invention is improved as compared with the reactor of the conventional structure, the present inventors create a reactor model in a computer, conduct a magnetic field analysis, and perform a magnetic field analysis near the coil model. The temperatures that can occur were identified. There are two types of models created, one of which is a model of the reactor of the present invention, and has the reactor structure shown in FIG. 1 (Example). The other is a model of a reactor having a conventional structure, and exhibits a structure that does not include the second magnetic flux channel (including the rotor) of the embodiment (comparative example).

  For both models, a condition where the high magnetic flux density (peak value) in the core is a saturation region of 1.8 T (Tesla) or more is generated by applying an AC high current with a zero peak of 200 A or more to generate a magnetic field in the core. Set to. In the set saturation region, the rotor of the embodiment can be driven to rotate. The result of the analysis is shown in FIG.

  In the same figure, the heat dissipation on the vertical axis represents the temperature directly above the coil of the comparative example as a reference 100% under the above analysis conditions, and the temperature directly above the coil of the example is expressed as a ratio to the result of the comparative example. is there.

  As a result of this analysis, it was proved that the heat dissipation performance of the example was improved by 15% with respect to the comparative example, that is, the temperature of the coil as the heat generation source could be reduced by 15%. It shows that a high current to which an incremental current value corresponding to a maximum temperature of about 15% is added can be applied.

  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 ... U-shaped core (magnetic core), 1a ... 1st core area | region, 1b ... 2nd core area | region, 1c ... 3rd core area | region, 1d ... 4th core area | region, 2 ... Gap layer, 3 ... Bobbin 4a, 4b ... coils (first coil, second coil), 5 ... rectangular core (magnetic core), 6a, 6b ... magnet, 7 ... rotor, 7a ... main channel, 7b ... branch channel, 7c ... Opening, 7d ... rotating shaft, 8 ... cooling medium flow path, 9 ... mold resin body, 10, 10A ... reactor, G1 ... magnetic flux flow in first magnetic flux flow path, G2 ... magnetic flux flow in second magnetic flux flow path

Claims (5)

A plurality of magnetic cores are connected via an insulating portion to form a reactor core that is substantially annular in plan view and forms a first magnetic flux flow path. A reactor in which first and second coils are respectively formed in two core regions;
Among the reactor cores, a second magnetic flux flow path is formed between the third core region and the fourth core region, which connects the first core region and the second core region,
The second magnetic flux passage has a coil inside thereof, a rotor for spreading the provided cooling medium around the magnet, and a magnet for defining the flow direction of the magnetic flux flowing through the second magnetic flux passage. And a reactor.   The reactor according to claim 1, wherein a part of the magnetic flux flowing through the first magnetic flux passage flows through the second magnetic flux passage.   Of the second magnetic flux flow path, the magnet is disposed in a region downstream of the magnetic flux flow, where the magnetic flux flowing through the second magnetic flux flow path merges with the first magnetic flux flow path, The reactor according to claim 1, wherein the magnet prevents the magnetic flux from flowing from the first magnetic flux channel to the downstream side of the second magnetic flux channel.   A main flow path through which the cooling medium flows and one or more branch flow paths extending from the main flow path in the radial direction of the rotor are defined in the rotor, and the branch flow paths face the circumferential surface of the rotor. The reactor according to claim 1, wherein the reactor is in fluid communication with the opening, and the cooling medium is sprayed around the rotor through the opening.   The reactor according to any one of claims 1 to 4, wherein a mold resin body is formed in a region that is at least around the coil and does not face the rotor while the rotor is maintained in a rotatable posture.

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