JP5267181B2 - Reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor capable of effectively cooling heat generated by a coil and also preventing reduction in inductance. <P>SOLUTION: The reactor has a core 13 made of a magnetic powder mixed resin having powder of a magnetic material dispersed in an insulating resin. The coil 11 which is supplied with electric power to generate magnetic flux is embedded in the core 13. Further, a plurality of plate-like heat radiating fins 2 made of a material having higher heat conductivity than the core 13 are provided in the core 13. The heat radiating fins 2 have their principal surfaces parallel to an axis A of the coil 11 and are provided in the core 13 radially around the axis A. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a reactor having a structure that easily cools heat generated by a coil and prevents a decrease in inductance.

The reactor includes, for example, a core made of a magnetic material and a coil wound around the core. Then, a magnetic flux is formed by energizing the coil.
When energizing the coil and operating the reactor, Joule heat is generated. If the temperature of the reactor rises too much due to this heat generation, the stability of the operation of the reactor may be impaired. Moreover, the temperature of the electronic components around the reactor may increase, and the operation stability of the electronic components may be impaired.
As a result, there is a risk of impairing the operational stability of a power converter or the like that incorporates such a reactor.

  Then, in order to suppress the temperature rise of a reactor, the reactor which provided the heat radiating member is proposed.

JP 2007-335833 A

Examples of conventional reactors are shown in FIGS. In this example, a core 92 made of a magnetic powder mixed resin in which a magnetic powder is dispersed in a resin material and a coil 93 are housed in a case 91. A ring-shaped heat dissipation member 94 is formed on the bottom surface of the case 91. The case 91 and the heat dissipation member 94 are made of aluminum, for example.
With this configuration, heat generated from the coil 93 is transmitted to the heat radiating member 94 through the core 92 (magnetic powder mixed resin) and further to the case 91, so that the coil 93 can be cooled.

However, the reactor 90 has a problem that the inductance tends to decrease because the heat dissipation member 94 prevents the flow of the magnetic flux Φ. When the size of the heat dissipating member 94 is increased, the inductance decreases, so that the heat dissipating member 94 must be made small as shown in FIG. 19, and it is difficult to improve heat dissipation.
In addition, when the magnetic flux Φ passes through the heat radiating member 94, an eddy current is generated, and the heat radiating member 94 generates heat.
Therefore, there is a demand for a reactor that can improve heat dissipation and prevent a decrease in inductance.

  This invention is made | formed in view of this conventional problem, and makes it a subject to provide the reactor which can cool the heat | fever generate | occur | produced from the coil effectively and can prevent the fall of an inductance.

The first invention comprises a core made of a magnetic powder mixed resin in which a magnetic powder is dispersed in an insulating resin;
A coil embedded in the core and generating magnetic flux when energized;
Made of a material having a higher thermal conductivity than the core, a plurality of plate-like radiating fins provided in the core,
A storage case for storing the core, the coil, and the radiation fin;
The heat dissipating fin is provided in the core such that the main surface thereof is parallel to the axis of the coil and is radially centered on the axis .
The heat radiating fin has a portion disposed inside the coil and a portion disposed outside the coil, and these two portions are connected to each other.
The storage case has a bottom wall, a side wall erected from the bottom wall in the axial direction of the coil, and an opening that opens in the axial direction.
The portion of the radiating fin that is disposed on the inner side and the portion that is disposed on the outer side of the radiating fin extends to a position closer to the opening than the end surface on the opening side of the both end surfaces of the coil. The reactor extends to a position closer to the bottom wall than the end face on the bottom wall side of both end faces of the coil (Claim 1).

The function and effect of the present invention will be described.
In the reactor, the plate-like radiating fins are provided so that the main surface thereof is parallel to the axis of the coil and is radially centered on the axis. If it does in this way, the area which the magnetic flux generated around the coil crosses the radiation fin can be minimized. For this reason, the flow of magnetic flux is less likely to be hindered by the radiating fins, and a reduction in inductance can be prevented.

  The heat radiating fin is formed of a metal having high thermal conductivity such as aluminum. Therefore, the heat generated from the coil and the core can be efficiently cooled. Aluminum has a magnetic resistance higher than that of the core, so that it is difficult for magnetic flux to pass through. Therefore, conventionally, when the area of the radiating fins is increased or the number of the fins is increased, there is a problem that the magnetic flux density in the core is lowered and the inductance is likely to be lowered. However, by disposing the radiating fins as described above, the radiating fins can be made not to oppose the flow of magnetic flux. That is, the area of the radiation fin that the magnetic flux crosses can be minimized, and the decrease in inductance can be suppressed.

  Moreover, according to the said structure, compared with a prior art example (refer FIG. 18, FIG. 19), even when a big radiation fin is used, the flow of magnetic flux is not prevented. Therefore, it is possible to increase the heat radiation efficiency while preventing the inductance from being reduced.

  As described above, according to the present invention, it is possible to provide a reactor that can effectively cool the heat generated from the coil and can prevent a decrease in inductance.

The cross-sectional view of the reactor in Example 1. FIG. The principal part enlarged view of FIG. FIG. Bb sectional drawing of FIG. The circuit diagram of the power converter device using the reactor in Example 1. FIG. The manufacturing process explanatory drawing of the reactor in Example 1. FIG. The figure following FIG. The figure following FIG. The figure following FIG. The cross-sectional view of the reactor which provided the thermal radiation fin only in the inner side of the coil in the reference example 1. FIG. Cc sectional drawing of FIG. The cross-sectional view of the reactor which provided the radiation fin only in the outer side of the coil in the reference example 1. FIG. Dd sectional drawing of FIG. Sectional drawing of the reactor in the reference example 2. FIG. FIG. 6 is a perspective view of the reactor in Example 2 with partial omission. The side view of the heat sink in Example 2. FIG. Ee arrow line view of FIG. The cross-sectional view of a reactor in a conventional example. Ff sectional drawing of FIG.

A preferred embodiment in each invention described above will be described.
In the first invention, the magnetic powder mixed resin is obtained by dispersing magnetic powder in an insulating resin. As the magnetic powder, for example, ferrite powder, iron powder, silicon alloy iron powder, or the like can be used. Moreover, as said insulating resin, thermosetting resins, such as an epoxy resin, and a thermoplastic resin can be used, for example.

  The reactor of this invention can be used for the power converter device mounted in a hybrid vehicle, an electric vehicle, etc., for example. Since a large current may flow in an automobile power converter, the amount of heat generated by the coil is large, and the effect obtained by the present invention is particularly great.

In the present invention, it is preferable that the upper KiOsamu pay case and the heat radiation fins are in contact (claim 2).
If it does in this way, since the heat generated from a coil and a core will be transmitted to a radiation case through a radiation fin, cooling efficiency can be raised. For example, the heat dissipating fins can be in contact with the bottom wall of the storage case or can be configured to be in contact with the side walls.

Further, the heat radiation fins, that are located on both the inside and the outside of the coil.
If it does in this way , heat dissipation efficiency can be improved. In addition, it is preferable that the inner side radiation fin arrange | positioned inside the coil and the outer side radiation fin arrange | positioned outside the coil are located on the same surface. In this way, compared to the case where they are arranged alternately, the magnetic flux easily passes through the core, so that the inductance is less likely to decrease. Moreover, the radiation fin provided in the outer side can be made to contact the bottom wall and side wall of a storage case. If it does in this way, since heat will be transmitted from both a bottom wall and a side wall, cooling efficiency will become high.

Moreover, the said radiation fin may be arrange | positioned only in either one of the inner side and the outer side of the said coil .
In this way, although the heat radiation efficiency is reduced compared to the case where heat radiation fins are provided on both the inside and the outside of the coil, the number of heat radiation fins made of aluminum with high magnetic resistance is small, so the inductance is reduced. Easy to suppress. Therefore, it can be suitably used when it is desired to increase the inductance even if the heat dissipation efficiency is low.

Further, a plate-like cooling member connected to the end face of the heat radiating fin in the axial direction of the coil is provided, and the heat radiating fin is formed in a shape in which the radial width becomes longer toward the end face in the axial direction. (Claim 3 ).
If it does in this way, since the quantity of the member (metal) used for a radiation fin can be reduced, cost reduction can be achieved. In addition, the cooling member is in contact with the end face of the radiating fin, and the length of the end face is long, so that the heat dissipation efficiency can be increased.

Moreover, it is preferable that the said radiation fin has a coil contact part which contacts the outer peripheral surface or inner peripheral surface of the said coil (Claim 4 ).
If it does in this way, since the contact area of a radiation fin and a coil becomes large, the cooling efficiency of the heat | fever which generate | occur | produced from the coil can be improved.

Example 1
A reactor according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a reactor 1 according to this example, and FIG. 2 is a partially enlarged view thereof. 3 is a cross-sectional view taken along the line aa in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line bb in FIG.
As shown in FIGS. 1 to 4, the reactor 1 of this example includes a core 13 made of a magnetic powder mixed resin in which a magnetic powder is dispersed in an insulating resin. A coil 11 that generates a magnetic flux Φ by energization is embedded in the core 13. Furthermore, a plurality of plate-like heat radiation fins 2 made of a material having a higher thermal conductivity than the core 13 are provided in the core 13. The heat radiating fin 2 is provided in the core 13 so that the main surface 20 (see FIG. 2) is parallel to the axis A of the coil 11 and is radially centered on the axis A.

  Further, the heat radiating fins 2 are arranged on both the inside and the outside of the coil 11. The inner radiating fins 2a provided on the inner side and the outer radiating fins 2b provided on the outer side are located on the same plane.

Further, as shown in FIG. 3, the present example includes a storage case 14 that stores the core 13, and the storage case 14 and the radiation fin 2 are in contact with each other.
More specifically, the inner radiating fin 2 a and the outer radiating fin 2 b are connected by the bottom radiating fin 2 c, and the bottom radiating fin 2 c is connected to the bottom wall 14 a of the storage case 14.
Further, the outer radiation fin 2 b is in contact with the side wall 14 b of the storage case 14.

In FIG. 5, the circuit diagram of the power converter device 80 for vehicles using the reactor 1 of this example is shown. The vehicular power conversion device 80 includes an inverter unit 86 and a converter unit 81. The voltage of the DC power supply 82 is boosted by the converter unit 81 and then converted into an AC voltage by the inverter unit 86. Then, the AC power is used to drive the three-phase AC motors 83 and 84 to drive the vehicle. The reactor 1 is used in the converter unit 81.
The inverter unit 86 is composed of a plurality of semiconductor modules 5. Each semiconductor module 5 includes an IGBT element 51 and a flywheel diode 52. As illustrated, the collector terminal 50a of one semiconductor module 5a and the emitter terminal 53b of the other semiconductor module 5b are DC input terminals. Further, the emitter terminal 53a of one semiconductor module 5a and the collector terminal 50b of the other semiconductor module 5b are connected to form an AC output terminal. The three-phase AC motor 83 is connected to the AC output terminal.

Next, the manufacturing method of the reactor 1 of this example is demonstrated.
First, as shown in FIG. 6, a mold 8 (different from the storage case 14) is prepared, and the radiating fins 2 and the coils 11 are placed therein. At this time, the heat dissipating fins 2 are arranged radially so that the main surface 20 thereof is parallel to the axis A of the coil 11.
Thereafter, as shown in FIG. 7, a liquid core 13 ′ in which a magnetic powder is dispersed in a liquid insulating resin is poured into the mold 8. As the insulating resin, for example, a thermosetting resin such as an epoxy resin is used. When the liquid core 13 ′ is poured into the mold 8 and heated, the thermosetting resin is cured, and the radiating fins 2, the coils 11, and the core 13 are integrated and hardened.
After solidification, as shown in FIG. 8, the member 6 in which the radiating fin 2, the coil 11, and the core 13 are integrated is taken out from the mold 8. When cooled, the volume of the core 13 shrinks somewhat, so that it can be removed from the mold 8 relatively easily.
On the other hand, a storage case 14 is prepared separately, and a small amount of liquid adhesive 7 is placed therein. For example, a urethane resin can be used as the adhesive. In this state, the member 6 is stored in the storage case 14. Thereby, the adhesive 7 is filled in the gap between the member 6 and the storage case 14, and the member 6 and the storage case 14 can be bonded.

Next, the function and effect of this example will be described.
In the reactor 1 of this example, the plate-like heat radiation fins 2 are provided such that the main surface 20 is parallel to the axis A of the coil 11 and is radially centered on the axis A. In this way, as shown in FIG. 2, the area where the magnetic flux Φ generated around the coil 11 crosses the radiation fin 2 can be minimized. Therefore, the flow of the magnetic flux Φ is less likely to be hindered by the heat radiating fins 2, and a reduction in inductance can be prevented.

  The radiating fin 2 is made of a metal having high thermal conductivity such as aluminum. Therefore, the heat generated from the coil 11 and the core 13 can be efficiently cooled. Aluminum has a magnetic resistance greater than that of the core 13, so that it is difficult for magnetic flux to pass through. Therefore, conventionally, when the area of the radiating fins 2 is increased or the number of the fins is increased, there is a problem that the magnetic flux density in the core 13 is lowered and the inductance is easily lowered. However, by disposing the radiating fins 2 as in this example, the radiating fins 2 can be made not to oppose the flow of the magnetic flux Φ. That is, the area of the radiation fin 2 that the magnetic flux Φ traverses can be minimized, and a decrease in inductance can be suppressed.

  Moreover, according to the said structure, compared with a prior art example (refer FIG. 18, FIG. 19), even when the wide radiation fin 2 is used, the flow of magnetic flux (PHI) is not prevented. Therefore, it is possible to increase the heat radiation efficiency while preventing the inductance from being reduced.

In this example, as shown in FIGS. 1 and 2, the heat radiation fins 2 are arranged on both the inside and the outside of the coil 11.
If it does in this way, since the number of the radiation fins 2 can be increased, the thermal radiation efficiency can be improved. In this example, the inner radiating fin 2a disposed inside the coil and the outer radiating fin 2b disposed outside the coil are located on the same plane. In this way, it is easier to prevent a decrease in inductance than in the case where they are arranged alternately.

As shown in FIG. 3, the reactor 1 of the present example includes a storage case 14 that stores the core 13, and the storage case 14 and the radiating fin 2 are in contact with each other.
If it does in this way, since the heat generated from coil 11 and core 13 will be transmitted to radiating fin 2, and will move to storage case 14, cooling efficiency can be raised. The storage case 14 can be provided with a cooling device (not shown) using a refrigerant or the like. Thereby, the thermal radiation efficiency of the coil 11 and the core 13 can be improved further.

  As described above, according to this example, it is possible to provide the reactor 1 that can effectively cool the heat generated from the coil 11 and can prevent a decrease in inductance.

( Reference Example 1 )
In this example, the arrangement of the radiation fins 2 is changed. FIG. 10 is a cross-sectional view of the reactor 1 in which the radiation fins 2 are provided only inside the coil 11, and FIG. 11 is a cross-sectional view taken along the line cc of FIG.
12 is a cross-sectional view of the reactor 1 in which the radiating fins 2 are provided only on the outside of the coil 11, and FIG. 13 is a cross-sectional view taken along the line dd of FIG.
In addition, the configuration is the same as that of the first embodiment.

With the above-described configuration, compared with the case where the heat radiation fins 2 are provided on both the inside and the outside of the coil 11, although the heat radiation efficiency is reduced, the number of heat radiation fins made of aluminum with high magnetic resistance is small. It is easy to suppress a decrease in inductance. Therefore, it can be suitably used when it is desired to increase the inductance even if the heat dissipation efficiency is low.
In addition, the same effects as those of the first embodiment are obtained.

( Reference Example 2 )
In this example, the shape of the radiating fin 2 is changed. As shown in FIG. 14, the reactor 1 of this example includes a plate-like cooling member 3 connected to the end face 21 of the heat radiating fin 2 in the axial direction of the coil 11. The radiating fin 2 is formed in a shape in which the radial width W becomes longer toward the end face 21 in the axial direction.
The cooling member 3 is an aluminum plate, for example, and is in contact with the storage case 14. The storage case 14 is provided with a cooling device (not shown), and the storage case 14 and the cooling member 3 are cooled by the cooling device.
In addition, the configuration is the same as that of the first embodiment.

If it does in this way, since the quantity of the member (metal) used for the radiation fin 2 can be reduced, cost reduction can be achieved. In addition, the cooling member 3 and the heat radiating fin 2 are connected to each other at the end face 21. Since the length of the end face 21 is long, the heat radiation efficiency is high.
In addition, the same effects as those of the first embodiment are obtained.

(Example 2 )
In this example, the shape of the radiating fin 2 is changed. FIG. 15 shows a partially omitted perspective view of the reactor 1 of this example. In FIG. 15, the heat dissipating fins 2 existing on the front side of the reactor are omitted. Further, FIG. 16 shows a side view of the radiating fin 2, and FIG. 17 shows a view taken along the line ee of FIG.
As illustrated, the heat dissipating fin 2 of this example includes a coil contact portion 4 that contacts the inner peripheral surface 11 a of the coil 11.
More specifically, as shown in FIGS. 16 and 17, the heat dissipating fin 2 of this example has a main body portion 24, and a cutout portion 23 is formed in the main body portion 24. The coil 11 is fitted into the notch 23. The main body 24 is connected to the cooling member 3 at the end face 21. The radiating fin 2 of this example is formed in a shape in which the radial width becomes longer toward the end face 21 as in the third embodiment. The coil contact portion 4 is formed on the main body portion 24.
Although not shown, the coil contact portion 4 may be in contact with the outer peripheral surface 11 b of the coil 11.
In addition, the configuration is the same as that of the first embodiment.

If it does in this way, since the contact area of the radiation fin 2 and the coil 11 becomes large by the coil contact part 4, the cooling efficiency of the heat | fever generated from the coil 11 can be improved.
In addition, the same effects as those of the first embodiment are obtained.

DESCRIPTION OF SYMBOLS 1 Reactor 11 Coil 13 Core 14 Storage case 2 Radiation fin 20 Main surface 21 End surface 23 Notch 3 Cooling member 4 Coil contact part Φ Magnetic flux A Axis line

Claims (4)

A core made of a magnetic powder mixed resin in which magnetic powder is dispersed in an insulating resin;
A coil embedded in the core and generating magnetic flux when energized;
Made of a material having a higher thermal conductivity than the core, a plurality of plate-like radiating fins provided in the core,
A storage case for storing the core, the coil, and the radiation fin;
The heat dissipating fin is provided in the core such that the main surface thereof is parallel to the axis of the coil and is radially centered on the axis .
The heat radiating fin has a portion disposed inside the coil and a portion disposed outside the coil, and these two portions are connected to each other.
The storage case has a bottom wall, a side wall erected from the bottom wall in the axial direction of the coil, and an opening that opens in the axial direction.
The portion of the radiating fin that is disposed on the inner side and the portion that is disposed on the outer side of the radiating fin extends to a position closer to the opening than the end surface on the opening side of the both end surfaces of the coil. The reactor extends to a position closer to the bottom wall than an end face on the bottom wall side of both end faces of the coil . In claim 1, a reactor, characterized in that the upper KiOsamu pay case and the heat radiation fins are in contact. 3. The plate-like cooling member connected to the end face of the heat dissipating fin in the axial direction of the coil according to claim 1, wherein the heat dissipating fin has a radial width toward the end face in the axial direction. The reactor is characterized in that it is formed into a long shape. In any one of claims 1 to 3, the heat radiation fins, a reactor, characterized in that it comprises a coil contact portion in contact with the outer peripheral surface or inner peripheral surface of the coil.

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