JP7049748B2 - Reactor - Google Patents

Description

The present invention relates to a reactor.

The reactor is used in various electric devices, and includes a reactor main body having a core and a pair of coils wound around the core, and a case for accommodating the reactor main body. As such a reactor, a magnetically coupled reactor is known.

The magnetically coupled reactor makes it difficult for the core to magnetically saturate by generating magnetic flux so that the directions of the magnetic fields face each other with a pair of coils, and it is possible to reduce the size by suppressing ripples using leakage inductance. It is a reactor to be.

Japanese Unexamined Patent Publication No. 11-345724

The magnetic coupling type reactor has the above-mentioned advantages, but on the other hand, it generates magnetic flux so that the directions of the magnetic fields face each other. Occur. Since this leakage flux spreads to the surroundings, it causes malfunction of parts such as equipment and sensors installed around the reactor, so the layout of the equipment and parts installed around the reactor is designed in consideration of the leakage flux. It had to be done, and the degree of freedom of layout was reduced. Alternatively, peripheral devices and parts have to be placed away from the reactor, resulting in an increase in the size of the devices and devices.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a reactor capable of reducing the spread of leakage flux.

The reactor of the present invention has a pair of coils that generate magnetic flux so that the directions of the magnetic fields face each other, a pair of legs on which the coils are mounted, and a yoke portion that is located outside the coils and connects the legs. The wall of the case comprises a reactor body comprising a core, a metal case containing the reactor body, and a magnetic material disposed outside the wall of the case close to the yoke portion. The height of the reactor body is lower than the height of the reactor body in the state of accommodating the reactor body, and the magnetic material is characterized in that it protrudes above the wall of the case .

The ratio of the length protruding from the upper end of the wall of the case to the length from the upper end of the wall of the case to the upper surface of the core of the magnetic material may be 0.5 to 1.3.

The case has a substantially rectangular parallelepiped shape in which an opening is provided on the upper surface and a storage space for the reactor body is formed by a wall, and the pair of coils mounted on the legs have both ends on the wall of the case. The magnetic material is a plate-like body and may be arranged along the wall of the case.

According to the present invention, it is possible to obtain a reactor capable of reducing the spread of the leakage flux.

It is a perspective view of the reactor which concerns on embodiment. It is an exploded perspective view of the reactor which concerns on embodiment. It is a side view of the reactor which concerns on embodiment. It is a top view of the reactor which concerns on embodiment. It is a top view of the reactor which concerns on embodiment, and is the schematic diagram which shows the state of the magnetic flux generated by energizing a coil. It is a side view of the reactor which concerns on embodiment, and is the schematic diagram which shows the leakage flux. It is a side view of the reactor which arranged the magnetic material inside the wall of a case, and is the schematic diagram which shows the leakage flux. It is a top view of the reactor which shows the evaluation point of leakage flux and ripple. It is sectional drawing explaining the reactor which concerns on other embodiment, and is the figure which shows the integration of a core and a magnetic material. It is sectional drawing explaining the reactor which concerns on other embodiment, and is the figure which shows the integration of a case and a magnetic material. It is sectional drawing explaining the reactor which concerns on other embodiment, and is the schematic diagram which shows the leakage flux passing through the case made of a magnetic material. It is a top view which explains the reactor which concerns on other embodiment, and is the figure which shows the modification about the arrangement of a coil.

[1. Embodiment]
Hereinafter, the reactor of the present embodiment will be described with reference to the drawings. This reactor is a magnetically coupled reactor for controlling voltage in an electric circuit, and can be used as an in-vehicle reactor for hybrid vehicles, electric vehicles, fuel cell vehicles, and the like.

[1-1. Constitution]
FIG. 1 is a perspective view of a reactor according to the present embodiment. FIG. 2 is an exploded perspective view of the reactor according to the present embodiment. FIG. 3 is a side view of the reactor according to the present embodiment. FIG. 4 is a plan view of the reactor according to the present embodiment.

In the present specification, the z-axis direction shown in the drawings is referred to as the "upper" side, and the opposite direction is referred to as the "lower" side. To explain the configuration of each member, "bottom" is also referred to as "bottom". The "upper" and "lower" refer to the positional relationship of each configuration of the reactor, and do not refer to the positional relationship or direction when the reactor is mounted on the actual machine to be installed. The z-axis direction may be referred to as a height direction, and the x-axis direction may be referred to as a width direction.

As shown in FIGS. 1 and 2, the reactor includes a reactor body 10, a case 4, and a magnetic body 6. The reactor body 10 includes a core 1 and a coil 5.

The core 1 is a magnetic material such as a dust core, a ferrite core, or a laminated steel plate, and the inside thereof serves as a path for magnetic flux generated by the coil 5 to form a magnetic circuit. The core 1 has a pair of leg portions 11 to which the coil 5 is mounted, and a yoke portion 12 that connects the leg portions 11 to each other. Here, the leg portions 11 are arranged so as to be parallel to each other, and the yoke portion 12 is arranged outside the coil 5. The core 1 of the present embodiment has U-shaped cores 1a and 1b, and both ends of the U-shaped cores 1a and 1b are abutted to form an annular shape. That is, the U-shaped cores 1a and 1b are composed of a pair of straight line portions 11a and 11b and connecting portions 12a and 12b connecting the pair of straight line portions 11a and 11b, and the leg portions 11 are composed of the straight line portions 11a and 11b. , The connecting portions 12a and 12b each constitute the yoke portion 12. The connecting portions 12a and 12b are also referred to as yoke portions 12a and 12b.

The straight portions 11a and 11b may be fixed with an adhesive, or may be directly abutted without using an adhesive. Further, a magnetic gap may be provided between the straight portions 11a and 11b. Examples of the magnetic gap include a configuration in which a spacer made of a non-magnetic material is provided between the straight portions 11a and 11b, and a configuration in which a gap is provided at the ends of the straight portions 11a and 11b.

Although the core 1 is not particularly shown, the periphery thereof may be covered with a resin member. This is to insulate the coil 5.

The coil 5 is a conducting wire having an insulating coating. The coil 5 of the present embodiment is a flat wire edgewise coil. However, the wire rod and winding method of the coil 5 are not particularly limited, and other forms may be used.

The coil 5 has a pair of coils 5a and 5b. The coils 5a and 5b are configured by winding, for example, one enamel-coated copper wire around a winding shaft. The coils 5a and 5b are attached to the legs 11, respectively. Since the legs 11 are parallel here, the coils 5a and 5b are also arranged in parallel. That is, the winding axes of the coils 5a and 5b are parallel. When the resin member is coated around the core 1, the resin member is interposed between the leg portion 11 and the coils 5a and 5b.

The coils 5a and 5b generate magnetic flux by energization. The generated magnetic flux flows out from one end of the coils 5a and 5b, passes through the outer portions of the coils 5a and 5b, and flows into the other ends of the coils 5a and 5b to form a closed magnetic path.

For example, both ends of the coils 5a and 5b are drawn out to the outside, one end thereof is connected to an external power source (not shown) via a bus bar which is a conductive member, and the other end portion is connected to an external electric device. The coils 5a and 5b generate magnetic flux so that the directions of the magnetic fields face each other when energized from an external power source. The magnetic flux here means a bundle of magnetic flux lines. The current flowing through the coils 5a and 5b is an alternating current, the phases are out of phase between the coils 5a and 5b, and the magnetic fluxes generated by the coils 5a and 5b repel each other.

The case 4 is an accommodating body for accommodating the reactor main body 10, and has a substantially rectangular parallelepiped shape with an open upper surface and a hollow inside. That is, the case 4 has a bottom surface portion 41 and a wall 42 rising upward from the edge of the bottom surface portion 41. Here, the bottom surface portion 41 has a quadrangular shape, and the case 4 is surrounded on all sides by a wall 42 to form a storage space for the reactor main body 10. The wall 42 is divided into four portions here, and is composed of a pair of walls 421 parallel to the x-axis direction (width direction) and a pair of walls 422 parallel to the y-axis direction.

As shown in FIG. 3, the height of the wall 42 is lower than that of the reactor body 10, and here it is lower than the height of the core 1 (the upper surface of the core 1).

As shown in FIG. 4, in the state where the reactor main body 10 is housed, the winding axis direction of the coils 5a and 5b is parallel to the y-axis, and the ends of the coils 5a and 5b are directed to the wall 421. Further, in this state, the yoke portion 12 is close to the wall 42 of the case 4. That is, the yoke portion 12 is close to the wall 421 extending in the x-axis direction.

The case 4 is made of metal. Specifically, any material such as aluminum or aluminum alloy that can obtain a magnetic shielding effect may be used. Lightweight metals with high thermal conductivity such as aluminum alloys are preferable.

The filler may be filled and solidified in the case 4. That is, a filling molding portion in which the filler is solidified may be provided in the gap between the case 4 and the reactor main body 10. As the filler, a resin that is relatively soft and has high thermal conductivity is suitable for ensuring the heat dissipation performance of the reactor body 10 and reducing the vibration propagation from the reactor body 10 to the case 4.

The magnetic body 6 is composed of a magnetic material and has a lower magnetic resistance than air or metal. The magnetic material 6 is a ferromagnet and can be made of the same material as the core 1. For example, it can be composed of a mixed material of pure iron and sendust.

The magnetic body 6 is a quadrangular plate-like body here, and is arranged on the outside of the wall 42 of the case 4 adjacent to the yoke portion 12. Here, the wall 42 on which the magnetic body 6 is arranged is a wall 421 parallel to the x-axis direction.

In the present embodiment, the magnetic body 6 is provided on the wall 421 via an adhesive, the lower part overlaps the wall 421 in the y-axis direction, and the upper part protrudes above the wall 421. In other words, the magnetic material 6 covers only the vicinity of the wall 421, and does not cover the entire reactor body 10.

In the magnetic body 6, the ratio of the length A of the magnetic body 6 protruding from the upper end of the wall 421 to the length H from the upper end of the wall 421 to the upper surface of the core 1 is 0.5 to 1.3. preferable. The magnetic body 6 extends downward with the bottom surface of the case 4 as a limit, and preferably extends to the height of the bottom surface of the case 4. Assuming that the height of the case 4 is K and the length of the magnetic body 6 overlapping the wall 421 in the z-axis direction is B, it is preferable that B ≦ K. The width of the magnetic body 6 is preferably not less than the width of the core 1 and not more than the width of the case 4. The width means the length in the x-axis direction. Further, the thickness of the magnetic body 6 is preferably thicker, and can be determined in relation to the amount of leakage flux. That is, when the leakage flux is large, the magnetic body 6 may be thicker, and when the leakage flux is small, the magnetic body 6 may be thin. The thickness direction of the magnetic body 6 is the y-axis direction here.

[1-2. Action]
FIG. 5 is a plan view of the reactor according to the present embodiment, and is a schematic view showing the magnetic flux generated by energizing the coil 5. The arrow shown in FIG. 5 indicates the magnetic flux. As shown in FIG. 5, the magnetic flux generated from the coils 5a and 5b forms a magnetic circuit inside the core 1 through the inside of the core 1. The magnetic flux leaked out of this magnetic circuit becomes the leakage flux.

Specifically, when alternating currents having different phases are passed through the coils 5a and 5b, magnetic flux is generated in the coils 5a and 5b so that the directions of the magnetic fields face each other, and the yoke portions 12a and 12b generate magnetic flux. Repel each other. As a result, the magnetic flux leaks to the outside of the yoke portions 12a and 12b. The magnetic flux leaked to the outside of the yoke portions 12a and 12b is the leakage flux. In FIG. 5, the magnetic fluxes repel each other in the yoke portion 12b, and the leakage flux is generated. However, since the current flowing through the coils 5a and 5b is alternating current, the leakage flux alternates between the yoke portion 12a and the yoke portion 12b. Occurs in.

The reactor of this embodiment positively utilizes the leakage flux. That is, the effective inductance Leq of this reactor is proportional to LM, where L is the inductance of the coils 5a and 5b and M is the inductance due to the leakage flux. When M is large (coupling ratio is small), Leq becomes small, which is not preferable as a product, and M is 0 (coupling ratio is 1), that is, L = M when there is no leakage flux, and Leq becomes 0 as a product. Not preferable. Therefore, in this reactor, the leakage flux is generated so that M is larger than 0 and as small as possible.

FIG. 6 is a side view of the reactor according to the present embodiment, and is a schematic view showing the leakage flux. The arrows shown in FIG. 6 indicate the magnetic field at each point, and the white arrows schematically indicate the direction of the leakage flux. The case 4 is displayed semi-transparently to display the magnetic field.

As shown in FIG. 6, the leakage flux is generated from the upper part of the yoke portion 12a, that is, above the wall 42 of the case 4, and tends to spread to the outside. Here, in the present embodiment, the magnetic body 6 is arranged on the outside of the wall 421 of the case 4. Since the magnetic resistance of the magnetic body 6 is smaller than that of air or other members of the reactor, the magnetic flux that tends to spread to the outside passes through the magnetic body 6. Therefore, it is possible to suppress the leakage and spread of the magnetic flux to the outside of the reactor.

Specifically, the leakage flux is captured at the portion of the magnetic body 6 protruding above the wall 421 of the case 4. Further, the magnetic body 6 extends below the wall 421 of the case 4. Therefore, the captured leakage flux flows downward and toward the other end side of the coils 5a and 5b, forming a closed magnetic path. As described above, the magnetic body 6 is composed of a magnetic flux capturing portion 61 which is a portion protruding above the wall 421 of the case 4, and a magnetic flux guiding portion 62 which guides the captured leakage flux so as to form a closed magnetic path. While allowing the generation of the leakage magnetic flux itself, the spread of the leakage magnetic flux to the outside is suppressed by changing the path of the magnetic flux that goes out to the outside.

The reason why the magnetic body 6 is arranged on the outside of the wall 421 will be described. FIG. 7 is a side view of the reactor in which the magnetic body 6 is arranged inside the wall 421 of the case 4, and is a schematic view showing the leakage flux. As shown in FIG. 7, the leakage flux leaked from the yoke portions 12a and 12b is captured by the magnetic body 6, but since the case 4 is made of metal and the magnetic flux does not easily pass through, the captured magnetic flux is captured by the magnetic body 6. It flows out from the part protruding upward from the wall 421 and spreads.

On the other hand, by arranging the magnetic body 6 on the outside of the wall 421, as shown in FIG. 6, the magnetic flux leaked from the yoke portions 12a and 12b flows toward the wall 421, but the wall 421 is difficult to pass the magnetic flux. , Heading upwards. Then, it is captured by the magnetic flux capturing unit 61 and guided to the closed magnetic path by the magnetic flux guiding unit 62 (see FIG. 3). As described above, since the magnetic flux guiding portion 62 overlapping with the wall 421 in the x-axis direction is arranged on the outside of the wall 421, the magnetic flux guiding function can be exerted, so that the magnetic body 6 is provided outside the wall 421. Have been placed.

[1-3. effect]
(1) The reactor of the present embodiment has a pair of coils 5a and 5b that generate magnetic flux so that the directions of magnetic fields face each other, a pair of legs 11 on which the coils 5a and 5b are mounted, and the outside of the coils 5a and 5b. A reactor body 10 having a core 1 having a yoke portion 12 located at and connecting the leg portions 11, a metal case 4 accommodating the reactor body 10, and a wall 421 of the case 4 close to the yoke portion 12. A magnetic material 6 arranged on the outside is provided.

As a result, it is possible to suppress the leakage and spread of the magnetic flux to the outside. That is, since the magnetic fluxes are generated from the pair of coils 5a and 5b so as to face each other inside the yoke portion 12, the magnetic fluxes repel each other and the magnetic flux leaks to the outside of the yoke portion 12. In the present embodiment, the magnetic material 6 is arranged on the outside of the wall 421 of the case 4 close to the yoke portion 12. Since the magnetic resistance of the magnetic body 6 is smaller than that of air or other members constituting the reactor, the magnetic flux leaking to the outside passes through the magnetic body 6. In other words, it is possible to change the path of the magnetic flux that tends to leak to the outside and suppress the leakage and spread of the magnetic flux to the outside. As a result, the degree of freedom in the layout of the surroundings where the reactor is installed can be increased.

In particular, if the entire reactor body 10 is covered with a magnetic member, it leads to an increase in the size of the reactor, and not only the advantage of the magnetically coupled reactor that enables miniaturization cannot be utilized, but also the space around the reactor and the degree of freedom in layout are increased. It will disappear. On the other hand, in the present embodiment, since the magnetic body 6 is arranged only on the outside of the wall 421 close to the yoke portion 12, the degree of freedom in layout is increased as compared with the case where the entire reactor body 10 is covered with the magnetic member. Can be done.

In order to suppress the leakage and spread of the magnetic flux to the outside in this way, the case 4 has a substantially rectangular parallelepiped shape in which an opening is provided on the upper surface and a storage space for the reactor main body 10 is formed by the wall 42 as in the present embodiment. The pair of coils 5a and 5b mounted on the legs 11 have both ends arranged in parallel toward the wall 421 of the case 4, and the magnetic body 6 is a plate-like body along the wall 421 of the case 4. Can be placed.

(2) The wall 421 of the case 4 is lower than the height of the reactor body 10 in the state where the reactor body 10 is housed, and the magnetic body 6 protrudes above the wall 421 of the case 4. As a result, the magnetic flux leaking to the outside can be captured more efficiently. As shown in FIG. 6, the magnetic flux leaking from the yoke portion 12a flows in the direction of the wall 421 of the case 4, but the case 4 itself is made of metal and it is difficult for the magnetic flux to pass through. On the other hand, the air above the case 4 has a lower magnetic resistance than the case 4. Therefore, the magnetic flux toward the wall 421 of the case 4 then flows toward the upper side of the case 4 and tries to leak to the outside through the upper portion of the wall 421 as a loophole. On the other hand, since the magnetic body 6 is provided so as to protrude above the wall 421 of the case 4 and closes the loophole, the leakage flux can be efficiently captured.

(3) The magnetic material 6 has a ratio of the length A protruding from the upper end of the wall 42 of the case 4 to the length H from the upper end of the wall 421 of the case 4 to the upper surface of the core 1 of 0.5 to 1. It was set to 3. As a result, the magnetic flux leaking to the outside can be captured more efficiently. That is, the magnetic fluxes generated from the coils 5a and 5b pass through the inside of the core 1 so as to face each other, and repel each other at the yoke portion 12. Since the repulsed magnetic flux leaks to the outside through the upper surface of the core 1, the magnetic flux density near the upper surface of the core 1 becomes high. Therefore, by setting the ratio of the protruding length of the magnetic material 6 from the case 4 to 0.5 to 1.3 with respect to the upper surface of the core 1, the magnetic flux leaking to the outside can be captured more efficiently. ..

(4) The magnetic material 6 is provided so as to extend downward with the bottom surface of the case 4 as a limit. As a result, it is possible to form a closed magnetic path in which the captured magnetic flux flows into the other end of the coils 5a and 5b. That is, the magnetic flux generated from the coils 5a and 5b flows out from one end of the coils 5a and 5b, passes through the outer portions of the coils 5a and 5b, and returns to the other ends of the coils 5a and 5b to form a closed magnetic path. Since the magnetic body 6 extends downward in this way, the captured magnetic flux can be guided to the other ends of the coils 5a and 5b to form a closed magnetic path, so that the magnetic flux can be reduced while reducing the leakage flux. Leakage spread can be suppressed.

(5) The magnetic material 6 has a width equal to or greater than the width of the core 1 and equal to or less than the width of the case 4. As a result, it is possible to further suppress the leakage and spread of the magnetic flux to the outside.

[2. Example]
Examples of the present invention will be described below with reference to FIGS. 3, 8 and 1-5. In the following examples, regarding the reactor shown in the above embodiment, (1) the presence or absence of a magnetic material, (2) the length of the magnetic material protruding upward, and (3) the length of the magnetic material in the height direction. Specific sample data in which (4) the width of the magnetic material and (5) the thickness of the magnetic material are changed. Each sample has the same configuration except that the arrangement and size of the magnetic material 6 are changed. As shown in FIG. 8, in each of the samples provided with the magnetic material 6, the magnetic material 6 was provided on the wall 421 so that the center in the x-axis direction was aligned with the reactor center axis parallel to the y-axis direction.

Each sample was evaluated by the average (mT) and ripple (mT) of the leakage flux at the evaluation points 1 to 4 shown in FIG. These evaluation results are the simulation results performed by a computer under the conditions shown in Tables 1 to 5 and the following analysis conditions. The average leakage flux (mT) is the calculated average of the leakage flux per AC current cycle. Specifically, it is obtained by dividing the sum of the maximum value and the minimum value of the leakage flux in one cycle by 2. Ripple is a fluctuation centered on the average of this leakage flux, and is the difference (peak to peak) between the maximum value and the minimum value in one cycle.

The evaluation points 1 to 4 are points on the xy plane separated from the upper surface of the case 4 by 1 mm in the z-axis direction. The evaluation point 1 is a point 5 mm away from the case 4 on the reactor central axis parallel to the y-axis. The evaluation point 2 is a point 5 mm away from the case 4 on the central axis of the coil 5a or the coil 5b parallel to the y-axis. The evaluation point 3 is an intersection of a line parallel to the wall 421 5 mm away from the wall 421 parallel to the x-axis and a line parallel to the wall 422 5 mm away from the wall 422 parallel to the y-axis. Evaluation point 4 is a point 5 mm away from the wall 422 on the center line of the reactor parallel to the x-axis.

(Analysis conditions)
-Reactor x, y, z-axis size: (x, y, z) = (91 mm, 116 mm, 44 mm)
-Height of case 4: 29.25 mm
-Overall width, leg width, height, and cross-sectional area of the legs of the U-shaped cores 1a and 1b: 72.1 mm, 20 mm, 25 mm, 500 mm ² (the sizes of the U-shaped cores 1a and 1b are the same).
・ Current passed through coils 5a and 5b: AC current with amplitude 44A and phase different by 180 ° ・ Number of turns of coils 5a and 5b: 48 turns ・ Material of case 4: Aluminum

(1) Presence or absence of magnetic material Sample 11 in which the magnetic material 6 was arranged outside the wall 421 of the case 4 and sample 10 in which the magnetic material 6 was not provided were analyzed. Specifically, as shown in Table 1, in the sample 11, as an example, the magnetic body 6 is attached to the wall 421 so that the upper side of the magnetic body 6 is along the upper side of the wall 421, and the sample 11 is magnetic. There is no protrusion from the wall 421 of the body 6. The length A (mm) protruding above the wall 421 of the case 4 of the magnetic material 6 is 0 mm. The size of the magnetic material 6 of the sample 11 is such that the width (length in the x-axis direction), the thickness (length in the y-axis direction), and the height (length in the z-axis direction) are 72.1 mm and 1 mm, respectively. It was set to 25 mm.

Table 1 shows the analysis results of the leakage flux (average) at the evaluation points 1, 3 and 4 for the samples 10 and 11.

As shown in Table 1, there is not much difference in the leakage flux at the evaluation points 3 and 4 between the sample 10 and the sample 11, but the leakage flux at the evaluation point 1 is 45.7 mT in the sample 11 as an example. It can be seen that the amount is lower than that of the sample 10 as a comparative example, which is 56 mT. From this, it can be seen that by arranging the magnetic material 6 on the outside of the case 4, the leakage and spreading of the magnetic flux to the outside can be reduced.

(2) Length of the magnetic material protruding upward As shown in Table 2, the wall 421 of the case 4 of the magnetic material 6 is arranged so that the size of the magnetic material 6 is kept constant and the magnetic material 6 is shifted upward. Samples 11 to 18 in which the length A protruding upward was changed between 0 mm and 25 mm were analyzed. The size of the magnetic body 6 has a width (length in the x-axis direction), a thickness (length in the y-axis direction), and a height (length in the z-axis direction) of 72.1 mm, 1 mm, and 25 mm, respectively. ..

The sample 11 is a sample in which the magnetic material 6 does not protrude from the wall 421 at all. Samples 12 to 17 are samples in which the magnetic material 6 protrudes above the wall 421 by 1, 3, 5, 9.5, 12.5, and 20 (all units are mm). The sample 18 is a sample in which all of the magnetic material 6 protrudes upward from the wall 421.

Table 2 shows the analysis results of the leakage flux at the evaluation points 1 to 4 for the samples 11 to 18. Further, the ratio α of the length B of the magnetic body 6 overlapping with the case 4 and the length A protruding from the upper end of the wall 421 to the length H from the upper end of the wall 421 to the upper surface of the core 1 and the case 4 The ratio β of the length B to the height K is also shown in Table 2.

As shown in Table 2, in the leakage flux 1 at the evaluation point 1, the samples 12 to 18 provided with the magnetic body 6 protruding above the wall 421 are averaged with respect to the sample 11 in which the magnetic body 6 does not protrude upward. It can be confirmed that the value is small and the leakage and spread of the magnetic flux to the outside are suppressed. The leakage flux at the evaluation point 1 tends to decrease when the magnetic body 6 protrudes more than the wall 421. In particular, it can be seen that the leakage flux 1 at the evaluation points 1 is remarkably reduced in the samples 14 to 16, and a larger leakage flux reduction effect can be obtained when the ratio α is in the range of 0.5 to 1.3. .. Further, it can be seen that when the ratio β is in the range of 0.43 to 0.68, a larger effect of reducing the leakage flux can be obtained.

Further, it can be confirmed that the leakage flux at the evaluation point 2 can be reduced in the samples 13 to 18 in which the magnetic material 6 protrudes upward by 3 mm or more. In particular, the effects of reducing the leakage flux are remarkable in the samples 14 and 15 in which the ratio α is 0.5 to 1.0 and the ratio β is 0.53 to 0.68.

(3) Length in the height direction of the magnetic material Samples 21 to 25 in which the width and thickness of the magnetic material 6 were constant and the length in the height direction was changed as shown in Table 3 were analyzed. The lengths, lengths A and B of the magnetic material 6 in the height direction are 35, 5, 30 for the sample 21, 12.5, 5, 7.5 for the sample 22, 35, 7, 28 for the sample 23, and the sample. 24 is 12.5, 2.5, 10 and sample 25 is 16.45, 4.45, 12. In each case, the unit is mm.

Table 3 shows the analysis results of the leakage flux at the evaluation points 1 to 4 for the samples 21 to 25. Table 3 also shows the ratios α and β.

As shown in Table 3, it can be seen that the larger the length B, the smaller the leakage flux at the evaluation point 1. For example, it can be confirmed that the length B of the samples 21 and 23 is relatively larger than that of the other samples, and the leakage flux at the evaluation point 1 is significantly reduced.

Focusing on the samples 21, 22 and 25, the ratio α is 0.5 in each case, while the ratio β increases in the order of the samples 22, 25 and 21 from 0.26 to 1.03. It can be seen that the leakage flux at the evaluation point 1 is reduced in this order. From this, it can be seen that even if the amount of protrusion of the wall 421 upward is the same, the leakage flux at the evaluation point 1 is reduced by extending the magnetic body 6 downward.

It can be seen that the sample 23 has the smallest leakage flux at the evaluation point 1. For example, as compared with the sample 21, even if the length of the magnetic body 6 in the height direction is the same, the length B of the sample 23 is 2 mm shorter and the length A is 2 mm longer. From this, it can be seen that the magnetic material 6 has a better capture efficiency of the leakage flux at the evaluation point 1 when the length A is lengthened than when the length B is lengthened. Further, since the leakage flux at the evaluation point 2 is remarkably reduced in the samples 21 and 23, it is preferable that the length of the magnetic body 6 in the height direction is long. For example, the ratio β is preferably 0.96 or more.

(4) Width of magnetic material Samples 14, 31 to 33, in which the length and thickness of the magnetic material 6 in the height direction were made constant and the widths were changed as shown in Table 4, were analyzed. In the samples 14, 31 to 33, the length and the thickness of the magnetic material 6 in the height direction are 25 mm and 1 mm, respectively, and the lengths A and B are 5 mm and 20 mm, respectively, which are the same.

The widths of the magnetic materials 6 of the samples 14, 31 to 33 were 72.1, 90.6, 47.1, and 16.6. The unit is mm.

Table 4 shows the analysis results of the leakage flux at the evaluation points 1 to 4 for the samples 14, 31 to 33. Table 4 also shows the ratio γ of the width of the magnetic material 6 to the width of the core 1. The width of the core 1 is the length of the U-shaped cores 1a and 1b in the x-axis direction, and is the distance between the outermost surfaces of the straight lines 11a and 11b parallel to the yz plane.

As shown in Table 4, it can be seen that when the width of the magnetic body 6 is large, the leakage flux at the evaluation point 1 is reduced. In particular, in the samples 14 and 31, it can be confirmed that the leakage flux at the evaluation point 2 is reduced as compared with the samples 32 and 33. From this, it can be seen that when the width of the magnetic body 6 is equal to or larger than the width of the core 1 (γ ≧ 1), the spread of the leakage flux can be further suppressed.

(5) Thickness of magnetic material Samples 14, 41 to 43, in which the width and length of the magnetic material 6 in the height direction were kept constant and the thickness was changed as shown in Table 5, were analyzed. In the samples 14, 41 to 43, the width and the length in the height direction of the magnetic body 6 are 72.1 mm and 25 mm, respectively, and the lengths A and B are 5 mm and 20 mm, respectively, which are the same.

The thickness of the magnetic material 6 of the samples 14, 41 to 43 was 1, 0.5, 2, and 3. The unit is mm.

Table 5 shows the analysis results of the leakage flux at the evaluation points 1 to 4 for the samples 14, 41 to 43.

As shown in Table 5, it can be seen that the leakage flux at the evaluation point 1 decreases as the thickness of the magnetic body 6 increases. Further, in the samples 14, 42, and 43, the leakage flux at the evaluation point 2 is reduced, and it can be seen that it is more preferable that the thickness of the magnetic body 6 is 1 mm or more in order to further suppress the spread of the leakage flux.

[3. Other embodiments]
The present invention is not limited to the above embodiment, but also includes other embodiments shown below. The present invention also includes a combination of all or any of the above embodiments and the following other embodiments. Further, various omissions, replacements, and changes can be made to these embodiments without departing from the scope of the invention, and modifications thereof are also included in the present invention.

(1) In the above embodiment, the magnetic body 6 is provided on the wall 421 via an adhesive, but as shown in FIG. 9, the core 1 and the magnetic body 6 are molded by the resin 20 and integrated. , May be placed on the outside of the wall 421. Further, as shown in FIG. 10, the case 4 and the magnetic body 6 may be molded by the resin 20 and integrated, and may be arranged on the outside of the wall 421. By integrally molding the core 1 or the case 4 and the magnetic body 6 in this way, the assembly man-hours can be reduced. In particular, when the resin member 21 is coated around the core 1 for insulation with the coil 5, the resin member 21 is formed by integral molding and the positional relationship between the magnetic material 6 and the core 1 is fixed. Is also good. That is, the resin 20 and the resin member 21 may be made of the same resin in succession. 9 and 10 are cross-sectional views taken along the central axis of the reactor parallel to the y-axis.

(2) In the above embodiment, the case 4 is made of metal, but it may be made of a magnetic material. When the case 4 is a magnetic material as described above, the magnetic material 6 does not necessarily have to be provided. FIG. 11 is a cross-sectional view of a reactor in which the case 4 is a magnetic material, and the white arrows in FIG. 11 indicate the leakage flux. This is because, as shown in FIG. 11, the case 4 itself serves as a path for the leakage flux, and the leakage spread of the magnetic flux can be suppressed.

For example, assuming that the case 4 has the same shape as that of the above embodiment, the wall 42 of the case 4 is close to the yoke portions 12a and 12b. The wall 421 captures the leakage flux from one end of the coils 5a and 5b and the yokes 12a and 12b, and guides them downward to the other end of the coils 5a and 5b via the bottom surface 41 and the other wall 421. Can be induced. The fact that the wall 42 of the case 4 is close to the yoke portions 12a and 12b means that a member having a magnetic resistance smaller than that of the wall 42 is not arranged between the yoke portions 12a and 12b and the wall 42. The case 4 is not particularly limited as long as it is a ferromagnetic material, but can be made of, for example, a dust core, a laminated steel plate, ferrite, or a composite magnetic material in which a magnetic powder and a resin are mixed.

By forming the case 4 including the magnetic material in this way, the reactor can be miniaturized and the degree of freedom in the peripheral layout can be increased because the magnetic material 6 is not provided.

(3) In the above embodiment, the core 1 is composed of U-shaped cores 1a and 1b, but a pair of C-shaped cores may be used. Further, a combination of a C-shaped core and an I-shaped core or a combination of four I-shaped cores may be used.

(4) In the above embodiment, the coil 5 is composed of two coils 5a and 5b, but the number is not particularly limited as long as the magnetic flux is generated so that the magnetic fields face each other.

(5) In the above embodiment, the coils 5a and 5b are arranged so that the winding axes are parallel, but as shown in FIG. 12, they may be arranged so as to be orthogonal to each other. In this case, the magnetic body 6 is provided at the corner of the case 4. Specifically, it is provided at the ends of the wall 421 and the wall 422. This is to capture the leakage flux and suppress the leakage spread of the magnetic flux. As described above, the magnetic body 6 may be arranged outside the yoke portion 12 in which the magnetic fluxes repel each other.

(6) In the above embodiment, the wall 42 is a square cylinder, but the wall 42 is not limited to this and may have a cylindrical shape.

10 Reactor body 1 Core 1a, 1b U-shaped core 11 Leg 12 York part 11a, 11b Straight part 12a, 12b Connecting part 4 Case 41 Bottom part 42 Wall 421, 422 Wall 5 Coil 5a, 5b Coil 6 Magnetic flux 61 Capture unit 62 Magnetic flux induction unit

Claims (5)

It includes a pair of coils that generate magnetic flux so that the directions of the magnetic fields face each other, a pair of legs to which the coils are mounted, and a core having a yoke portion located outside the coils and connecting the legs. The reactor body and
A metal case containing the reactor body and
A magnetic material placed on the outside of the wall of the case close to the yoke portion, and
Equipped with
The wall of the case is lower than the height of the reactor body in the state where the reactor body is housed.
The magnetic material must protrude above the wall of the case.
Reactor featuring. The ratio of the length protruding from the upper end of the wall of the case to the length from the upper end of the wall of the case to the upper surface of the core of the magnetic material is 0.5 to 1.3.
The reactor according to claim 1 . The magnetic material is provided so as to extend downward with the bottom surface of the case as a limit.
The reactor according to claim 1 or 2, wherein the reactor is characterized by. The case has a substantially rectangular parallelepiped shape in which an opening is provided on the upper surface and a storage space for the reactor body is formed by a wall.
The pair of coils mounted on the legs are arranged with both ends parallel to the wall of the case.
The magnetic material is a plate-like body and is arranged along the wall of the case.
The reactor according to any one of claims 1 to 3 . The magnetic material has a width equal to or greater than the width of the core and equal to or less than the width of the case.
The reactor according to any one of claims 1 to 4 .

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