JP2009111151A - Reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor capable of suppressing unwanted heating and suppressing dropping of inductance. <P>SOLUTION: The reactor 1 comprises a coil 2 which generates magnetic flux under energization, a core 3 formed by curing a magnetic powder mixed resin packed in the interior and on the outer periphery of the coil 2, and a case 4 for housing the coil 2 and the core 3 in the interior. At least at a part of the case 4, an electrically insulating part 5 having electrical insulation property is arranged so as to shield a closed path of the magnetic flux generated when the coil 2 is energized which is orthogonal to the portion passing through the case 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reactor used in a power conversion device or the like.

  2. Description of the Related Art Conventionally, there is a power conversion device such as an inverter for use in generating a drive current for energizing an AC motor that is a power source of an electric vehicle or a hybrid vehicle. For example, a reactor that constitutes a part of a booster circuit for boosting an input voltage is accommodated in the power converter.

As shown in FIGS. 8 and 9, the conventional reactor 9 includes a coil 92 that generates a magnetic flux when energized, a core 93 that is formed by curing a magnetic powder mixed resin filled inside and around the coil 92, and It has a case 94 that houses the coil 92 and the core 93 inside (see, for example, Patent Document 1).
Then, as shown in FIG. 9, when the coil 92 is energized, a magnetic flux φ is formed on the inner side and the outer periphery of the coil 92. This magnetic flux φ passes through the core 93 and the case 94.

JP 2007-27185 A

  However, when the magnetic flux φ passes through the case 94, the following problem occurs. That is, the magnetic flux φ passes through the inner side surface 940 in the case 94 due to the skin effect. At this time, a small amount of eddy current is generated in each part in the case 94 by the electromagnetic induction of the magnetic flux φ. The minute eddy currents merge with each other, and a relatively large eddy current 8 flows in a circumferential shape on a closed path perpendicular to the portion of the magnetic flux φ passing through the case 4.

  As described above, when the relatively large eddy current 8 flows in the case 94 and is unnecessary for the reactor performance, a loss may occur and the amount of heat generated by the reactor 9 may increase. Moreover, by this, there exists a possibility that the inductance of the reactor 9 may fall and electrical performance may fall.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a reactor that can suppress unnecessary heat generation and suppress a decrease in inductance.

The present invention includes a coil that generates magnetic flux when energized, a core formed by curing a magnetic powder mixed resin filled inside and around the coil, and a case that accommodates the coil and the core inside. A reactor,
In the case, at least part of the case has an electric insulating portion having electric insulation so as to block a closed path perpendicular to a portion of the magnetic flux generated by energizing the coil passing through the case. It is in the reactor characterized by being arrange | positioned (Claim 1).

The function and effect of the present invention will be described.
In the case, at least part of the case has an electric insulating portion having electric insulation so as to block a closed path perpendicular to a portion of the magnetic flux generated by energizing the coil passing through the case. It is arranged. The closed path can be electrically divided on the path by the electrical insulating portion. Thereby, it is possible to suppress a small amount of eddy currents generated by electromagnetic induction of the magnetic flux from joining each other and relatively large eddy currents flowing in a circumferential manner in the case.
As a result, it is possible to reduce a loss caused by an eddy current unnecessary for reactor performance flowing in the case. Thereby, while being able to suppress unnecessary heat_generation | fever, the fall of the inductance of a reactor can be suppressed.

  Thus, according to the present invention, it is possible to provide a reactor that can suppress unnecessary heat generation and suppress a decrease in inductance.

In the invention of the present invention (Invention 1), the resin used for the magnetic powder mixed resin is, for example, a material obtained by mixing magnetic powder into the resin. And as said magnetic powder, ferrite powder, iron powder, silicon alloy iron powder etc. can be used, for example. Moreover, as resin used for the said magnetic powder mixed resin, thermosetting resins, such as an epoxy resin, and a thermoplastic resin can be used, for example.
Moreover, it is preferable that the said case consists of a metal excellent in heat conductivity, such as aluminum or aluminum alloy, for example.

Moreover, it is preferable that the said electrical insulation part is arrange | positioned so as to be substantially orthogonal to the said closed path | route (Claim 2).
In this case, it is possible to efficiently suppress the eddy currents generated by the electromagnetic induction of the magnetic flux from joining each other and to efficiently suppress the flow of a relatively large eddy current in the case.

Moreover, the said electrical insulation part may be arrange | positioned in the multiple places of the said case (Claim 3).
Also in this case, the effect of this invention can fully be exhibited.

Moreover, it is preferable that the said electrical insulation part consists of a notch part which notches the said case (Claim 4).
In this case, since an electrical insulation part can be formed without providing other members, a low-cost reactor excellent in production efficiency can be obtained.

Moreover, it is preferable that the said case has two or more said notch parts, and the wall part between the said notch parts in the said case is urged | biased inside (Claim 5).
In this case, the core can be mechanically held by pressing the core inward by the biasing force applied to the wall portion of the case. Therefore, a reactor excellent in production efficiency can be obtained.

Moreover, it is preferable that the said electrical insulation part fits the resin which has electrical insulation in the said notch part (Claim 6).
In this case, it is possible to easily obtain an electrical insulation part having excellent electrical insulation. In addition, since the notch can be closed by the resin, it is possible to prevent the magnetic powder mixed resin from leaking out of the notch when filling the inner and outer periphery of the coil in the case with the magnetic powder mixed resin. it can.
In addition, as said resin which has the electrical insulation, an epoxy resin, a urethane resin, etc. can be used, for example.

Further, the case includes a planar bottom surface portion and a side surface portion rising from the bottom surface portion, and has an opening at a position facing the bottom surface portion, and the electrical insulating portion is the bottom surface of the side surface portion. Preferably, it is formed from the end on the side to the end on the opening side.
In this case, the eddy currents generated by the electromagnetic induction of the magnetic flux can be sufficiently prevented from joining each other, and a relatively large eddy current can be reliably prevented from flowing in the case.

The electrical insulating portion is formed on the side surface portion and is formed from an edge of the bottom surface portion toward the center of gravity of the bottom surface portion, and the electrical insulating portion formed on the bottom surface portion and the above It is preferable that the electrical insulating portions formed on the side surface portions are connected to each other at the respective end portions (claim 8).
In this case, it is possible to suppress a relatively large eddy current from flowing due to a small amount of eddy currents joining each other not only on the side surface but also on the bottom surface.

Preferably, the electrical insulating portion is disposed on a wall portion of the case where a projection surface is formed when the coil is projected onto the case radially outward. ).
In this case, the electrical insulating portion can be disposed in a portion where the magnetic flux due to energization to the coil easily passes in the case. Therefore, it can suppress more efficiently that a comparatively big eddy current flows in a case. In addition, since the electrical insulating portion can be efficiently disposed, the material cost of the electrical insulating portion can be reduced.

Moreover, it is preferable that the said case has the thermal radiation surface which discharge | releases the heat | fever of the said coil and the said core outside in the wall part of the said case other than the part in which the said electrical-insulation part is formed (Claim 10).
In this case, the heat dissipation and electrical insulation of the reactor can be reliably ensured.

(Example 1)
The reactor which concerns on the Example of this invention is demonstrated using FIG. 1, FIG.
As shown in FIG. 1, the reactor 1 of this example includes a coil 2 that generates a magnetic flux when energized, a core 3 that is formed by curing a magnetic powder mixed resin filled inside and outside the coil 2, and a coil 2. And a case 4 that accommodates the core 3 inside.
The case 4 has at least a part of the electric insulating portion 5 having electric insulation so as to block a closed path perpendicular to a portion passing through the case 4 in the magnetic flux generated by energizing the coil 2. Is arranged.

Below, the reactor 1 of this example is demonstrated in detail.
The reactor 1 of this example is provided in a power conversion device such as an inverter used for generating a drive current to be supplied to an AC motor that is a power source of an electric vehicle, a hybrid vehicle, or the like.

The resin used for the magnetic powder mixed resin is, for example, a material obtained by mixing magnetic powder into the resin. And as said magnetic powder, ferrite powder, iron powder, silicon alloy iron powder etc. can be used, for example. Moreover, as resin used for the said magnetic powder mixed resin, thermosetting resins, such as an epoxy resin, and a thermoplastic resin can be used, for example.
Moreover, it is preferable that the said case consists of a metal excellent in heat conductivity, such as aluminum or aluminum alloy, for example.

The core 3 in the reactor 1 of this example is formed in a substantially cylindrical shape as shown in FIG.
The coil 2 is configured to have a substantially cylindrical shape by winding a conductor wire 20 made of, for example, a copper wire in a spiral shape. For example, the coil 2 can be energized by passing a current from one end 21 of the conductor wire 20 constituting the coil 2 toward the other end 22.

As shown in FIG. 2, the case 4 has a substantially quadrangular prism shape. That is, the case 4 includes a rectangular bottom surface portion 42 and four side surface portions 41 that rise vertically from the bottom surface portion 42. An opening 43 is formed at a position facing the bottom surface 42.
Moreover, the part which accommodates the coil 2 and the core 3, ie, the inside of the case 4, consists of a recessed part formed in a substantially cylindrical shape.
In addition, a protrusion 420 is formed on the bottom surface portion 42 from the bottom surface portion 42 toward the opening 43 side.

  In addition, the case 4 has a heat radiating surface 45 that releases the heat of the coil 2 and the core 3 to the outside in the wall portion 40 of the case 4 other than the portion where the electrical insulating portion 5 is formed. That is, in this example, the heat radiation surface 45 is formed on the three side surface portions 41 and the bottom surface portion 42 other than the side surface portion 41 on which the electrical insulating portion 5 is disposed. The heat inside the coil 2 is radiated from the bottom surface portion 42 via the core 3 and the protruding portion 420.

As shown in FIG. 2, the electrical insulating portion 5 is disposed so as to be substantially orthogonal to a closed path orthogonal to a portion of the magnetic flux generated by energizing the coil 2 that passes through the case 4.
Specifically, the electrical insulating portion 5 is formed from the end portion 413 on the opening 43 side to the bottom surface portion 42 in one side surface portion 41 of the four side surface portions 41.
In addition, the electrical insulating portion 5 is formed by fitting a resin 50 having electrical insulation into a cutout portion 44 formed by cutting out the wall portion 40 of the case 4. As this resin 50, an epoxy resin, a urethane resin, etc. can be used, for example.

Next, the manufacturing procedure of the reactor 1 of this example is demonstrated using FIG. 1, FIG.
First, the resin 50 is fitted into the notch 44 formed in advance to form the electrical insulating portion 5.
Next, the coil 2 is inserted into the case 4 from the opening 43 and disposed at a predetermined position in the case 4. Specifically, the coil 2 is disposed so as to surround the projecting portion 420 formed on the case 4 while arranging a spacer or the like on the bottom surface portion 42 to keep the distance between the coil 2 and the bottom surface portion 42 constant. To do.

Next, liquid magnetic powder mixed resin is poured into the inside and the outer periphery of the coil 2 in the case 4. Here, the notch 44 is formed in the case 4. Since the resin 50 is fitted in the notch 44, the magnetic powder mixed resin does not leak from the notch 44.
Next, the magnetic powder mixed resin is cured to form the core 4, whereby the reactor 1 of this example is formed.

The function and effect of this example will be described below.
The case 4 has at least a part of the electric insulating portion 5 having electric insulation so as to block a closed path perpendicular to a portion passing through the case 4 in the magnetic flux generated by energizing the coil 2. Is arranged. With the electrical insulating portion 5, the closed path can be electrically divided on the path. Thereby, it is possible to suppress a small amount of eddy currents generated by electromagnetic induction of the magnetic flux from being merged with each other and relatively large eddy currents flowing in a circumferential manner in the case 4.
As a result, it is possible to reduce a loss caused by an eddy current unnecessary for reactor performance flowing in the case 4. Thereby, unnecessary heat generation can be suppressed and a decrease in inductance can be suppressed.

In addition, since the electrical insulating portion 5 is disposed so as to be substantially orthogonal to the closed path, the eddy currents generated by electromagnetic induction of the magnetic flux are efficiently suppressed from being combined with each other in the case 4. It is possible to efficiently suppress the flow of a relatively large eddy current.
In addition, the electrical insulating portion 5 includes a cutout portion 44 formed by cutting out the case 4. Thereby, since the electrical insulation part 5 can be formed without providing another member, the low-cost reactor 1 excellent in production efficiency can be obtained.

  Moreover, since the electrical insulation part 5 is formed by fitting the resin 50 having electrical insulation into the notch part 44, the electrical insulation part 5 having excellent electrical insulation can be easily obtained. Further, since the notch 44 can be blocked by the resin 50, the magnetic powder mixed resin leaks out from the notch 44 when the magnetic powder mixed resin is filled in the inside and the outer periphery of the coil 2 in the case 4. Can be prevented.

Further, the electrical insulating portion 5 is formed from the end portion on the bottom surface portion 42 side of the side surface portion 41 to the end portion on the opening portion 43 side. Therefore, it is possible to sufficiently prevent the eddy currents generated by the electromagnetic induction of the magnetic flux from joining each other and reliably prevent a relatively large eddy current from flowing in the case 4.
In addition, since the case 4 has a heat radiating surface that releases the heat of the coil 2 and the core 3 to the outside in the wall portion 40 of the case 4 other than the portion where the electrical insulating portion 5 is formed, the heat dissipation of the reactor 1 and Electrical insulation can be reliably ensured.

  Thus, according to this example, it is possible to provide a reactor that can suppress unnecessary heat generation and suppress a decrease in inductance.

(Example 2)
This example is an example of a reactor 1 in which the core 3 and the case 4 have a substantially quadrangular prism shape, as shown in FIG.
The coil 2 is also configured to have a substantially quadrangular prism shape by winding the conductor wire 20 in a spiral shape.

Moreover, in the reactor 1 of this example, the two electric insulation parts 5 are arrange | positioned in the one side part 41 among the four side parts 41. FIG. The two electrical insulating portions 5 are formed from the end portion of the side surface portion 41 on the opening 43 side to the bottom surface portion 42.
In preparing the reactor 1 of this example, for example, a coil integrated core 10 formed by integrating the coil 2 and the core 3 is prepared in advance, and then stored in the case 4.
Others are the same as in the first embodiment.

In the case of this example, since the coil-integrated core 10 can be easily accommodated in the case 4, the reactor 1 can be easily manufactured.
When the case 4 is configured such that the wall portion 40 of the case 4 sandwiched between the two electrical insulating portions 5 is urged inward, the coil-integrated core 10 is pressed by the wall portion 10. This can be mechanically held.
In addition, the same effects as those of the first embodiment are obtained.

(Example 3)
In this example, as shown in FIG. 4, the electrical insulating portion 5 is disposed on the wall portion 40 of the case 4 where the projection surface is formed when the coil 2 is projected onto the case 4 radially outward. It is an example of the reactor 1 which is. That is, the case 4 has a rectangular bottom surface portion 42 and four side surface portions 41 that rise vertically from the bottom surface portion 42. And the electrical insulation part 5 is arrange | positioned in the part in which the projection surface is formed when the coil 2 is projected on the one side part 41 of them.
Others are the same as in the first embodiment.

In the case of this example, in the case 4, the electrical insulating portion 5 can be disposed in a portion where magnetic flux due to energization to the coil 2 easily passes. Therefore, it is possible to more efficiently suppress a relatively large eddy current from flowing in the case 4. Moreover, since the electrical insulation part 5 can be arrange | positioned efficiently, the material cost of the electrical insulation part 5 can also be reduced.
The other functions and effects are the same as those of the first embodiment.

Example 4
This example is an example of the substantially cylindrical case 4 in which the electrical insulating portion 5 is formed on the side surface portion 41 and the bottom surface portion 42 as shown in FIG. That is, in the side surface portion 41 and the bottom surface portion 42, a cutout portion 44 as the electrical insulating portion 5 is formed.

Specifically, the bottom surface portion 42 has a substantially circular shape, and a cutout portion 44 is formed from the end portion to substantially the center. Further, the side surface portion 41 has a substantially cylindrical shape, and a cutout portion 44 is formed from the end portion on the bottom surface portion 42 side to the end portion on the opening portion 43 side. And the notch part 44 formed in the bottom face part 42 and the notch part 44 formed in the side part 41 are mutually connected in each edge part.
Others are the same as in the first embodiment.

In the case of this example, it is possible to suppress a relatively large eddy current from flowing due to a small amount of eddy currents joining each other not only on the side surface portion 41 but also on the bottom surface portion.
In addition, the same effects as those of the first embodiment are obtained.

(Example 5)
In this example, as shown in FIGS. 6 and 7, the case 4 has a plurality of notches 44, and the wall 40 between the notches 44 in the case 4 is urged inward. It is an example of the reactor 1. That is, in the case 4, two cutout portions 44 are formed on each of the four side surface portions 41. In the state where the core 3 is accommodated in the case 4, the wall portion 40 between the notches 44 is formed so as to incline so as to fall inward, and attached to the inside. It is energized.

In producing the reactor 1 of this example, first, as shown in FIG. 6A, the core 3 is formed on the inner side and the outer circumference of the coil 2 to produce the coil integrated core 10.
Next, as shown in FIG. 6 (b), a force is applied outward to the end portion on the opening 43 side of the wall portion 40 between the cutout portions 44 formed in each of the four side surface portions 41. .
Next, the coil-integrated core 10 is inserted in the direction of the arrow Y in a state where the end portion is expanded in the direction of the arrow X in FIG.

Next, by releasing the force applied to the end of the wall 40 on the opening 43 side, the coil-integrated core 10 is pressed inward by the biasing force applied to the wall 40. Hold this.
The reactor 1 of this example as shown in FIG.6 (c) can be formed by the above procedure.
Other configurations are the same as those in the first embodiment.

In the case of this example, the coil-integrated core 10 can be mechanically held by pressing the core 3 inward by the urging force applied to the wall portion 40 of the case 4.
In addition, the same effects as those of the first embodiment are obtained.

The longitudinal cross-sectional view of the reactor in Example 1. FIG. FIG. 3 is a perspective development view of the reactor in the first embodiment. The perspective development view of the reactor in the second embodiment. The longitudinal cross-sectional view of the reactor in Example 3. FIG. The perspective view of a case in Example 4. FIG. In Example 5, (a) The longitudinal cross-sectional view of the case which shows the state before accommodating a coil integrated core in a case, (b) The longitudinal cross-sectional view of the case which shows the state which accommodates the coil integrated core in a case (C) The longitudinal cross-sectional view of a reactor. The top view of the case in Example 5. FIG. The cross-sectional view of a reactor in a conventional example. AA line sectional view in FIG.

Explanation of symbols

1 Reactor 2 Coil 3 Core 4 Case 5 Electrical insulation

Claims (10)

A reactor having a coil that generates a magnetic flux when energized, a core formed by curing a magnetic powder mixed resin filled inside and outside the coil, and a case that houses the coil and the core inside. ,
In the case, at least part of the case has an electric insulating portion having electric insulation so as to block a closed path perpendicular to a portion of the magnetic flux generated by energizing the coil passing through the case. A reactor characterized by being arranged.   The reactor according to claim 1, wherein the electrical insulating portion is disposed so as to be substantially orthogonal to the closed path.   3. The reactor according to claim 1, wherein the electrical insulating portion is disposed at a plurality of locations of the case.   The reactor according to any one of claims 1 to 3, wherein the electrical insulating portion includes a cutout portion formed by cutting out the case.   5. The reactor according to claim 4, wherein the case includes a plurality of the cutout portions, and a wall portion between the cutout portions in the case is urged inward.   6. The reactor according to claim 4, wherein the electrical insulating portion is formed by fitting an electrically insulating resin into the cutout portion.   The case according to any one of claims 1 to 6, wherein the case includes a planar bottom surface portion and a side surface portion rising from an edge of the bottom surface portion, and has an opening at a position facing the bottom surface portion. The reactor is characterized in that the electrical insulating portion is formed from an end portion on the bottom surface side of the side surface portion to an end portion on the opening side.   8. The electrical insulation portion according to claim 7, wherein the electrical insulation portion is formed on the side surface portion and is formed from an edge of the bottom surface portion toward a center of gravity of the bottom surface portion, and the electrical insulation formed on the bottom surface portion. And the electrical insulating portion formed on the side surface portion are connected to each other at respective end portions.   9. The electrical insulating portion according to claim 1, wherein the electrical insulating portion is disposed on a wall portion of the case where a projection surface is formed when the coil is projected onto the case radially outward. Reactor characterized by being.   The case according to any one of claims 1 to 9, wherein the case has a heat radiating surface that releases heat of the coil and the core to the wall portion of the case other than a portion where the electrical insulating portion is formed. A reactor characterized by having.

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