JP5140064B2 - Reactor - Google Patents

Description

  The present invention relates to a reactor suitably used for, for example, an electric circuit or an electronic circuit.

  A reactor is a passive element using a winding, and is used, for example, for preventing harmonic current in a power factor correction circuit, smoothing current pulsation in a current type inverter or chopper control, and boosting a DC voltage in a converter. Yes. In recent years, there is a demand for downsizing in various product fields, and thus downsizing of reactors is also required.

  Such a reactor is disclosed in Patent Document 1, for example. The reactor disclosed in Patent Document 1 is incorporated in a hollow hole of a bobbin around which a coil is wound, and a pair of soft magnetic alloy dust cores in the form of a rod that serves as an attachment winding shaft of the coil, and the pair of soft magnetic A pair of plate-like soft ferrite cores that are combined at both ends of the alloy dust core and form a quadrilateral composite core with the pair of soft magnetic alloy dust cores. With such a configuration, the reactor disclosed in Patent Document 1 is reduced in size and loss. In the reactor disclosed in Patent Document 1, a gap is provided in the facing portion between the soft magnetic alloy dust core and the soft ferrite core so that the inductance is about 2 mH at 0A.

  When such a gap is provided in the core portion, problems of noise and magnetic flux leakage generally occur. Moreover, since the dimensional accuracy of the gap of the core portion affects the inductance characteristics of the reactor, it is necessary to form the gap with high accuracy. For this reason, the problem that the processing cost of a reactor becomes high will also arise. As the noise countermeasure, a ceramic material can be used for the gap portion. However, such a noise countermeasure increases the processing cost of the reactor.

  Thus, for example, Patent Document 2 discloses a reactor for the purpose of noise countermeasures and leakage flux countermeasures. The reactor disclosed in Patent Document 2 includes a core portion and a coil disposed outside the core portion, and is a reactor in which a closed magnetic path passing through the core portion is formed by excitation of the coil, The core portion is substantially composed of a material having a relative permeability of 5 to 50. With such a configuration, the reactor disclosed in Patent Document 2 has no gap in the core portion, and the problem of noise and leakage magnetic flux caused by having the gap is solved.

JP 2007-128951 A Japanese Patent Laid-Open No. 2008-112935

  However, in the reactor disclosed in Patent Document 2, since the relative magnetic permeability of the core portion is low, a relatively large leakage magnetic flux is generated from the core portion itself. And there exists a possibility of producing heat in the peripheral equipment of a reactor by this leakage magnetic flux. On the other hand, there is a disadvantage that the inductance characteristics of the reactor are easily influenced by the arrangement of the peripheral devices of the reactor. In order to reduce such an inconvenience, it is necessary to increase the volume of the core portion of the reactor, which is not effective for the purpose of downsizing the reactor.

  Further, when the reactor is used in an electric circuit, an electronic circuit, or the like, since the controllability of the current is improved when the rate of change of the current flowing through the reactor is constant, so-called BH curve linearity is desired.

  The present invention has been made in view of the above-described circumstances, and its object is to eliminate a gap that causes noise and magnetic flux leakage, can be further reduced in size, and, in addition, has better current controllability. Is to provide reactors.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, the reactor according to one aspect of the present invention includes a first core portion, a second core portion, a first coil wound only around the first core portion, at least the first core portion and the second core. A second coil wound so as to include both of the core parts, and a connecting core part that interconnects the first and second core parts, wherein the first coil and the second coil are electrically Are connected in series, the magnetic permeability of the first core portion is lower than the magnetic permeability of the connecting core portion, and the magnetic permeability of the second core portion is lower than the magnetic permeability of the connecting core portion. It is characterized by that.

  The reactor having such a structure has a structure in which the first core portion and the second core portion are connected by the connecting core portion, and a gap that causes noise and leakage magnetic flux is eliminated. For this reason, the reactor according to the present invention can suppress leakage magnetic flux leaking from the reactor to the external space. And while adopting the structure which eliminated such a gap, while the magnetic permeability of a 1st core part and the magnetic permeability of a 2nd core part are made relatively low, the magnetic permeability of a connection core part is made relatively high. . For this reason, the reactor according to the present invention is advantageous in terms of saturation magnetic flux, and can be further downsized. As described above, the permeability of the first core portion and the permeability of the second core portion are relatively lowered, while the permeability of the connecting core portion is relatively increased. For this reason, by compensating the change in the magnetic permeability with respect to the change in the magnetic flux density in the connection core portion having a relatively high permeability by the first core portion and the second core portion having a relatively low permeability, in the reactor, Since the linearity of the so-called BH curve (relation between excitation magnetic field and magnetic flux density) is improved, current controllability is improved. Therefore, the reactor according to the present invention does not have a gap that causes noise and leakage magnetic flux, and can be further reduced in size. In addition, the current controllability is improved.

  The reactor described above preferably further includes a third core portion, wherein the first coil is disposed outside the first core portion, and the second core portion is disposed outside the first coil. The second coil is disposed outside the second core portion, the third core portion is disposed outside the second coil, and the connecting core portion is formed of the first and second coils. The first to third core parts are connected to each other so as to cover both ends, and the magnetic permeability of the first core part is lower than the magnetic permeability of the third core part and the connecting core part, And the magnetic permeability of the said 2nd core part is lower than each magnetic permeability of the said 3rd core part and the said connection core part.

  In the reactor having such a configuration, the first coil including the first core portion and the second coil including the second core portion are surrounded by the third core portion and the connecting core portion, and a gap that causes noise and leakage magnetic flux is formed. It has a lost structure. For this reason, the reactor concerning this aspect can suppress the leakage magnetic flux which leaks from a reactor to external space. And while adopting the structure which eliminated such a gap, while the magnetic permeability of a 1st core part and the magnetic permeability of a 2nd core part are made relatively low, the magnetic permeability of a 3rd core part, and the connection core part of The permeability is relatively high. For this reason, the reactor according to this aspect is advantageous in terms of saturation magnetic flux, and can be further downsized. As described above, the permeability of the first core portion and the permeability of the second core portion are relatively lowered, while the permeability of the third core portion and the permeability of the connecting core portion are relatively increased. . For this reason, the change of the magnetic permeability with respect to the change of the magnetic flux density in the third core portion and the connecting core portion having a relatively high magnetic permeability is compensated by the first core portion and the second core portion having a relatively low magnetic permeability. Thus, since the linearity of the so-called BH curve (relation between the excitation magnetic field and the magnetic flux density) in the reactor is improved, in addition, the current controllability is improved. Therefore, the reactor according to this aspect has no gap that causes noise and leakage magnetic flux, and can be further downsized, and in addition, the current controllability is improved.

  In the above-described reactor, preferably, the first core portion is configured by a pair of rod-shaped first core members, and the first coil is wound around each of the pair of first core members. And the pair of coils are electrically connected in series, the second core portion is composed of a pair of rod-shaped second core members, and the pair of second core members Each is arranged outside the pair of coils constituting the first coil, the second coil is constituted by a pair of coils electrically connected in series, and one of the pair of coils is The one coil is wound so as to include one of the pair of coils constituting the first coil and one of the pair of second core members, and the other of the pair of coils constitutes the first coil. The other of the pair of coils and the other of the pair of second core members are wound, and the connecting core portion includes the pair of first core members and the second core portion constituting the first core portion. All of the pair of second core members constituting the above are connected to each other.

  The reactor having such a configuration is structurally different from the reactor having the above configuration, but is equivalent in terms of a magnetic circuit, and has the same effect as the reactor having the above configuration.

  In the above-described reactor, the first and second core portions are formed by molding a mixture of soft magnetic powder and non-magnetic powder. According to this configuration, desired magnetic characteristics (low magnetic permeability) can be obtained relatively easily for the first and second core portions, and a desired shape can be formed relatively easily.

  In the above-described reactors, the connecting core portion is formed by molding a soft magnetic powder. Alternatively, the third core part is formed by molding a soft magnetic powder. According to this configuration, the desired magnetic properties (high magnetic permeability) can be obtained relatively easily and the desired shape can be formed relatively easily for the third core portion and the connecting core portion.

  In the above-described reactors, the first and second core portions are made of the same material. According to this configuration, since a plurality of material types are not used, the cost can be reduced.

  Moreover, the reactor of the aspect which has these above-mentioned 3rd core parts WHEREIN: The said 3rd core part and a connection core part are the same materials, It is characterized by the above-mentioned. According to this configuration, since a plurality of material types are not used, the cost can be reduced.

  Here, these same materials may have different compositions as long as they are electromagnetically the same, not only when the compositions are the same.

  Moreover, in these above-mentioned reactors, each initial relative magnetic permeability of the said 1st and 2nd core part is 2-20, respectively, and the initial relative magnetic permeability of the said connection core part is 50-250, respectively. Features. Alternatively, the initial relative magnetic permeability of the first and second core parts is 2 to 20, respectively, and the initial relative magnetic permeability of the third core part is 50 to 250, respectively.

  According to this configuration, a current-inductance characteristic generally required for a reactor, that is, a current-inductance characteristic in which the inductance is substantially constant (including a case where the current is in a minute predetermined range) with respect to a change in current. Can be realized.

  The reactor according to the present invention does not have a gap that causes noise and leakage magnetic flux, and can be further reduced in size. In addition, the current controllability is improved.

It is a figure which shows the structure of the reactor in embodiment. It is a circuit diagram which shows the magnetic equivalent circuit of the reactor in embodiment. It is a figure which shows the magnetic characteristic in the material with a comparatively low density of a magnetic body used for the reactor of embodiment. It is a figure which shows the magnetic characteristic in the material used for the reactor of embodiment, and the density of a magnetic body is comparatively high. It is a figure which shows the structure of the reactor in one Example. It is a figure for demonstrating the structure of the coil in the reactor of one Example. It is a figure for demonstrating how to wind the said coil. It is a figure which shows the bias current-inductance characteristic in the reactor of one Example. It is sectional drawing which shows the structure of the reactor in one comparative example. It is sectional drawing which shows the structure of the reactor in another one comparative example. It is a figure which shows the magnetic characteristic in the other material with a comparatively high density of a magnetic body. It is a figure which shows the relationship between the density in a magnetic body containing iron powder, and a magnetic flux density-relative magnetic permeability characteristic. It is a figure which shows the structure of the reactor in another embodiment.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably.

  The reactor in the present embodiment includes a first core part, a second core part, a first coil wound around only the first core part, and at least both the first core part and the second core part. A second coil wound so as to include a connecting core portion that connects the first and second core portions to each other, and the first coil and the second coil are electrically connected in series. The magnetic permeability of the first core portion is lower than the magnetic permeability of the connecting core portion, and the magnetic permeability of the second core portion is lower than the magnetic permeability of the connecting core portion.

  As a more specific aspect of the reactor of such an aspect, the reactor further includes a third core portion, the first coil is disposed outside the first core portion, and the second core portion is the first core. Disposed outside the coil, the second coil is disposed outside the second core portion, the third core portion is disposed outside the second coil, and the connecting core portion is the first core. The first to third core parts are connected to each other so as to cover both ends of the second coil, and the magnetic permeability of the first core part is determined by the permeability of each of the third core part and the connecting core part. A reactor having a magnetic permeability lower than the magnetic permeability of the second core portion and lower than the magnetic permeability of the third core portion and the connecting core portion will be described below. It is not limited to, and the reactor of the above aspect Although the concrete manner, another configuration in configuration equivalent to the magnetic circuit manner the same effect as the reactor of the above aspect.

  Drawing 1 is a figure showing the composition of the reactor in an embodiment. 1A shows a top view when the connecting core portion is removed, and FIG. 1B shows a cross-sectional view cut in the radial direction including the central axis. FIG. 2 is a circuit diagram showing a magnetic equivalent circuit of the reactor in the embodiment. FIG. 3 is a diagram illustrating magnetic characteristics of a material having a relatively low density of magnetic materials used in the reactor according to the embodiment. FIG. 4 is a diagram illustrating magnetic characteristics of a material having a relatively high density of magnetic materials used in the reactor according to the embodiment. The horizontal axis in FIGS. 3 and 4 is the magnetic flux density, and the vertical axis is the relative permeability.

  In FIG. 1, a reactor D according to the embodiment includes a first core portion 1, a first coil 2 disposed outside the first core portion 1, and a second core portion 3 disposed outside the first coil 2. And the second coil 4 arranged outside the second core part 3, the third core part 5 arranged outside the second coil 4, and both ends of the first and second coils 2, 4. Connection core portions 6 and 6 that connect the first to third core portions 1, 3, and 5 are provided so as to cover each other. That is, in the reactor D, the first coil 2 including the first core portion 1 and the second coil 4 including the second core portion 3 are surrounded by the third core portion 5 and the connecting core portions 6 and 6. A type reactor.

  The first core part 1 has a solid columnar shape having predetermined magnetic characteristics described later, and the second core part 3 has a predetermined magnetic characteristic described later and is a cylinder having the same height as the first core part 1. The third core portion 5 has a predetermined magnetic characteristic, which will be described later, and has a cylindrical shape having the same height as the first core portion 1 (second core portion 3). The 2nd core part 3 is an internal diameter which can include the 1st coil 2 provided with the 1st core part 1 as a core (magnetic core), and the 3rd core part 5 is the core (magnetic core) of the 2nd core part 3. It is an internal diameter which can enclose the 2nd coil 4 provided as. Therefore, the inner diameter of the second core part 3 is at least larger than the outer diameter of the first core part 1 by the thickness of the first coil 2, and the inner diameter of the third core part 5 is larger than the outer diameter of the second core part 3. The thickness of the second coil 4 is at least larger.

  The connecting core portions 6 and 6 are discs having predetermined magnetic characteristics described later, and the outer shape thereof is larger than the inner diameter of the third core portion 5. One of the connecting core parts 6, 6 (upper connecting core part 6) has one end part of the first core part 1, one end part of the second core part 3, and the third core part 5 so as not to generate a substantial gap. The other end of the first core portion 1 and the second core portion are connected to the other end portion of the first core portion 1 so as not to generate a substantial gap. 3 and the other end of the third core portion 5 are connected to each other. In addition, the connection core parts 6 and 6 may each be shape | molded separately, and any one of the connection core parts 6 and 6 may be shape | molded integrally with the 3rd core part 5. FIG.

  The first coil 2 is a member obtained by winding a conductor wire, a conductor sheet or the like around the outer periphery of the first core part 1 a predetermined number of times, and includes an outer peripheral surface of the first core part 1, inner surfaces of the connecting core parts 6 and 6, It is arranged in the first space formed by the inner peripheral surface of the second core part 3. The second coil 4 is a member obtained by winding a conductor wire or a conductor sheet or the like around the outer periphery of the second core portion 3 a predetermined number of times, and includes an outer peripheral surface of the second core portion 3, inner surfaces of the connecting core portions 6 and 6, and The third core portion 5 is disposed in the second space formed by the inner peripheral surface. The first coil 2 and the second coil 4 are electrically connected in series.

  The first space may be filled with the first coil 2 without a substantial gap, or there may be a gap with the first coil 2 disposed. Similarly, the second space may be filled with the second coil 4 with almost no gap, or there may be a gap with the second coil 4 disposed. From the viewpoint of conducting heat generated in each of the first and second coils 2 and 4 toward the outside and dissipating the heat to the outside, the first and second spaces are made of a resin (relatively high in heat conductivity). It is preferably filled with a conductive resin).

When the magnetic equivalent circuit is considered, the reactor D having such a structure is a parallel magnetic circuit shown in FIG. In the magnetic equivalent circuit of the reactor D, a series connection circuit of a third magnetoresistance (= L1 / (μ ₁ × S ₁ ) and a second magnetoresistance (= L3 / (μ ₃ × S ₃ ) is a magnetomotive force n ₁ ×. In addition to being connected to both ends of I, a series connection circuit of a magnetomotive force n ₂ × I and a first magnetic resistance (= L2 / (μ ₂ × S ₂ ) is connected in parallel to the second magnetic resistance.

Here, n ₁ is the number of turns of the second coil 4, and n ₂ is the number of turns of the first coil 2. μ ₁ and S ₁ are the magnetic permeability and the cross-sectional area of the third core part 5, respectively, and L ₁ is the center of the lower connecting core part 6 from the center of the upper connecting core part 6 via the third core part 5. , And μ ₂ and S ₂ are the magnetic permeability and cross-sectional area of the first core portion 1, respectively, L ₂ is equal to the height of the first core portion 1, and μ ₃ And S ₃ are the magnetic permeability and the cross-sectional area of the second core portion 3, respectively, and L ₃ is from the center of the upper connecting core portion 6 to the center of the lower connecting core portion 6 via the second core portion 3. Magnetic path length. I is a current flowing through the first and second coils.

  Here, it should be noted that the magnetic permeability of the first core portion 1 is lower than the magnetic permeability of the third core portion 5 and the connecting core portions 6 and 6, and the magnetic permeability of the second core portion 2 is It is provided so that it may become lower than each magnetic permeability of the 3rd core part 5 and the connection core part 6. FIG.

  For example, the first and second core portions 1 and 3 are made of soft magnetic powder and non-magnetic powder from the viewpoint of easy realization of desired magnetic properties (low magnetic permeability) and easy shape forming of a desired shape. It is preferable that the mixture is molded. The mixing ratio ratio between the soft magnetic powder and the nonmagnetic powder can be adjusted relatively easily, and the magnetic characteristics of the first core portion 1 and the second core portion 3 can be adjusted by appropriately adjusting the mixing ratio. It is possible to easily achieve the desired magnetic properties (desired magnetic properties) (low magnetic permeability). Further, since it is a mixture of soft magnetic powder and non-magnetic powder, it can be formed into various shapes, and the shape of the first core portion 1 and the shape of the second core portion 3 can be easily made into desired shapes, respectively. It becomes possible to mold into. Moreover, it is preferable that the 1st and 2nd core parts 1 and 3 are the same material from a viewpoint of cost reduction.

  Similarly, the soft magnetic powder of the third core portion 5 and the connecting core portions 6 and 6 is a ferromagnetic metal powder, and more specifically, for example, pure iron powder, iron-based alloy powder. (Fe—Al alloy, Fe—Si alloy, Sendust, Permalloy, etc.) and amorphous powder, and iron powder having an electrical insulating film such as a phosphoric acid-based chemical film formed on the surface thereof. These soft magnetic powders can be produced, for example, by a method of making fine particles by an atomizing method or the like, or a method of finely pulverizing iron oxide or the like and then reducing it. In general, since the saturation magnetic flux density is large when the magnetic permeability is the same, the soft magnetic powder is particularly preferably a metal-based material such as the above pure iron powder, iron-based alloy powder, and amorphous powder.

  The first and second core parts 1 and 3 are formed by mixing iron powder as a soft magnetic powder and resin as a nonmagnetic powder by using, for example, a known conventional means. This is a member (low permeability member) having a density of 2.7 g / cc, and this member has, for example, the magnetic flux density-relative permeability characteristics shown in FIG. The magnetic flux density-relative permeability characteristic is a change in relative permeability with respect to a change in magnetic flux density. The magnetic flux density-relative magnetic permeability characteristics of the low magnetic permeability members used for the first and second core portions 1 and 3 are as follows. When the magnetic flux density slightly increases from the initial relative magnetic permeability of about 2.8, the magnetic flux density It is a profile in which the relative permeability increases rapidly to about 3.5 at about 0.02 T, and then the relative permeability gradually decreases as the magnetic flux density increases. In the example shown in FIG. 3, the magnetic flux density at which the relative magnetic permeability again becomes the initial relative magnetic permeability as the magnetic flux density increases from the initial relative magnetic permeability is about 0.52T.

  On the other hand, for example, the third core portion 5 and the connecting core portions 6 and 6 are formed of soft magnetic powder from the viewpoint of easy realization of desired magnetic properties (high magnetic permeability) and ease of forming a desired shape. The same material is preferable from the viewpoint of cost reduction.

  The third core portion 5 and the connecting core portions 6 and 6 are, for example, members (high magnetic permeability members) having a density of 7.0 g / cc obtained by compacting iron powder by using known conventional means. Yes, this member has, for example, the magnetic flux density-relative permeability characteristic shown in FIG. The magnetic flux density-relative magnetic permeability characteristics of the high magnetic permeability member used for the third core portion 5 and the connecting core portions 6 and 6 are as follows. When the magnetic flux density is increased from the initial relative magnetic permeability of about 120, the magnetic flux density is about In this profile, the relative permeability gradually increases to about 200 at 0.35 T, and then the relative permeability gradually decreases as the magnetic flux density increases. In the example shown in FIG. 4, the magnetic flux density at which the relative permeability becomes the initial relative permeability again as the magnetic flux density increases from the initial relative permeability is about 1T.

  As can be seen from a comparison between FIG. 3 and FIG. 4, the low permeability member has a faster relative permeability (with a smaller magnetic flux density) and a maximum value than the high permeability member. Yes.

  In the reactor D having such a configuration, the first coil 2 including the first core portion 1 and the second coil 4 including the second core portion 3 are surrounded by the third core portion 5 and the connecting core portions 6 and 6. It is a so-called pot type, and has a structure that eliminates a gap that causes noise and leakage magnetic flux. For this reason, the reactor D of this embodiment can suppress the leakage magnetic flux that leaks from the reactor D to the external space. And while adopting such a structure with no gap, the permeability of the first core part 1 and the permeability of the second core part 3 are relatively lowered, while the permeability and connection of the third core part 5 are relatively low. The magnetic permeability of the core parts 6 and 6 is made relatively high. For this reason, the reactor D of this embodiment is advantageous in terms of saturation magnetic flux, and can be further downsized. As described above, the permeability of the first core portion 1 and the permeability of the second core portion 3 are relatively lowered, while the permeability of the third core portion 5 and the permeability of the connecting core portions 6 and 6 are reduced. Is relatively high. The magnetic flux density-relative permeability characteristics of the relatively high permeability third core portion 5 and the connecting core portions 6 and 6 are, for example, the profile shown in FIG. 4 as the relative permeability increases as the magnetic flux density increases. This is compensated by the magnetic flux density-relative magnetic permeability characteristics of the first core portion 1 and the second core portion 3 having a relatively low magnetic permeability, so that the so-called BH curve (excitation magnetic field and magnetic flux density) in the reactor D can be obtained. The linearity of the relationship is improved. That is, in the example shown in FIGS. 3 and 4, as described above, the high relative permeability member used for the third core portion 5 and the connecting core portions 6 and 6 has a range in which the relative permeability is greater than or equal to the initial relative permeability. Then, as the magnetic flux density increases, the relative permeability gradually increases from the initial relative permeability and gradually decreases after taking the maximum value. On the other hand, the low relative permeability used for the first and second core portions 1 and 3 When the relative permeability exceeds the initial relative permeability, the member increases relatively rapidly from the initial relative permeability as the magnetic flux density increases, and gradually decreases after the relative permeability reaches the maximum value. The magnetic flux densities that can take the maximum value of the relative permeability are different from each other, and the ratio of the change in the relative permeability to the change in the magnetic flux density is different from each other. Is better It made. For this reason, as the linearity of the BH curve is improved, the rate of change of the current flowing through the reactor D becomes more constant, so that the controllability of the current in, for example, the booster circuit is improved. As a result, the circuit can operate more stably.

  As described above, the reactor D of the present embodiment has no gap that causes noise and leakage magnetic flux, can be further reduced in size, and, in addition, has better current controllability.

Next, an example of the present invention and a comparative example thereof will be described.
(Examples and Comparative Examples)
FIG. 5 is a diagram illustrating a configuration of a reactor in one embodiment. FIG. 5A shows a cross-sectional view cut in the radial direction including the central axis, and FIG. 5B shows a top view when the connecting core portion is removed. FIG. 6 is a diagram for explaining a configuration of a coil in the reactor according to the embodiment. FIG. 7 is a view for explaining how to wind the coil. FIG. 8 is a diagram illustrating a bias current-inductance characteristic in the reactor according to the embodiment. The horizontal axis in FIG. 8 is the bias current (A), and the vertical axis is the inductance (μH). FIG. 9 is a cross-sectional view illustrating a configuration of a reactor in one comparative example. FIG. 10 is a cross-sectional view showing a configuration of a reactor in another comparative example.

  In one embodiment, the reactor D1 has a reactor current in the range of 0 to 100 A, an inductance of 195 μH ± 15 μH, and leakage flux to the surroundings is 100 G at a point 10 mm away from the wall surface of the third core portion 5 of the reactor D1. Designed to fit within (Gauss). Note that the leakage magnetic field can be an index of a magnetic field that affects surrounding devices. The low magnetic permeability members of the first core portion 1 and the second core portion 3 are used in a range where the relative magnetic permeability is equal to or higher than the initial relative magnetic permeability, and the third core portion 5 and the connecting core portions 6, 6 The high magnetic permeability member is used in a range where the relative magnetic permeability is equal to or higher than the initial relative magnetic permeability.

  When the reactor D having the structure shown in FIG. 1 is designed according to such specifications, the reactor D1 of this embodiment has the dimensions shown in FIGS. 5 and 6, and as a result, the magnetic characteristics shown in FIG. 8 are obtained. . That is, in the reactor D1 of this embodiment, as shown in FIGS. 5 and 6, the first core portion 1 has a solid cylindrical shape with a radius (outer diameter) of 12 mm and a height of 22 mm, as shown in FIG. It is formed of a low permeability member having a magnetic property and a density of 2.7 g / cc. The second core portion 3 has a cylindrical shape with an inner diameter of 20 mm and an outer diameter of 45 mm and a height of 22 mm, and is formed of a low permeability member having a magnetic property shown in FIG. 3 and a density of 2.7 g / cc. The third core portion 5 has a cylindrical shape with an inner diameter of 50 mm, an outer diameter of 62 mm, and a height of 22 mm, and is formed of a high permeability member having a magnetic property shown in FIG. 4 and a density of 7.0 g / cc. The connecting core portions 6 and 6 are discs having a radius (outer diameter) of 62 mm and a thickness of 10 mm, and are formed of a high permeability member having a magnetic property shown in FIG. 4 and a density of 7.0 g / cc. The first coil 2 (inner coil) has 9 turns, and is formed in a first space formed on the outer periphery of the first core portion 1 with a length of 8 mm (= 20 mm-12 mm) in the radial direction. Be contained. The second coil 4 (outer coil) has a winding number of 15 turns, and is formed in a second space formed on the outer periphery of the second core portion 3 with a length of 5 mm (= 50 mm−45 mm) in the radial direction. Be contained.

  Such first and second coils 2, 4 are incorporated into the first to third core parts 1, 3, 5 by, for example, the following method. First, as shown in FIG. 7 (A), ribbon-like conductor sheets wound from both ends are prepared, and the middle part thereof is a direction perpendicular to the longitudinal direction in a plane including the conductor sheet by plastic molding, for example. Is bent by a predetermined angle. Subsequently, as shown in FIG. 7B, the bent portion is brought into contact with the outer peripheral surface of the first core portion 1, and the number of turns of the first coil 2 starts from the contact point of the conductor sheet. In this example, the winding is wound around the outer peripheral surface of the first core portion 1 so as to be 9 turns, and DP winding is performed using the first core portion 1 as a winding frame. Subsequently, as shown in FIG. 7C, the first core portion 1 in which the conductor sheet is wound as the first coil 2 has a second core portion (bypass) in which a gap for taking out the conductor sheet is formed. ) 3 is inserted so that the unrolled portion of the conductor sheet is taken out to the outside through the gap. Subsequently, as shown in FIG. 7D, the unwinding of the conductor sheet taken out to the outside becomes the number of turns of the second coil 4, starting from the take-out point from the gap, in this example, 15 turns. Thus, it winds around the outer peripheral surface of the 2nd core part 3, and DP winding is carried out by making the 2nd core part 3 into a winding frame. Subsequently, as shown in FIG. 7E, the conductor sheet is cut leaving a part for the connection end (for lead-out). Subsequently, as shown in FIG. 7F, the second core part 3 (including the first core part 1 and the first coil 2) obtained by winding the conductor sheet as the second coil 4 is used for the connection end. It is inserted into the third core part 5 formed with a gap for taking out the conductor sheet so that the conductor sheet for the connecting end is taken out through the gap. By such a procedure, the first and second coils 2 and 4 are incorporated in the first to third core portions 1, 3 and 5.

  The reactor D1 of one embodiment configured with such a design value has a magnetic characteristic as shown in FIG. 8 and has an inductance of about 180 μH at a bias current of about 100 A when the bias current is in the range of about 0 to 100 A. (Minimum value), about 210 μH (maximum value) at a bias current of about 18 A, and satisfies the specification of 195 μH ± 15 μH. And in the reactor D1 of this one Example, the leakage magnetic field was 55 G at the maximum at the point of distance 10mm from the wall surface of the 3rd core part 5 of the reactor D1. Further, the volume of the reactor D of this embodiment is about 507 cc (= 62 mm × 62 mm × 3.14 × 42 mm).

  On the other hand, as shown in FIG. 9, the reactor Dc1 of one comparative example includes an inner core portion 11, a coil 12 disposed outside the inner core portion 11, and an outer core portion 13 disposed outside the coil 12. A gapless reactor that is not a parallel structure and includes connecting core portions 14 and 14 that connect the inner core portion 11 and the outer core portion 13 to each other so as to cover both end portions of the coil 12.

  In the reactor Dc1 having the configuration shown in FIG. 9, similarly to the reactor D1 of the embodiment, the inductance is 195 μH ± 15 μH in the reactor current range of 0 to 100 A, and the leakage flux to the surroundings is the reactor Dc1. If the design is such that the specification falls within 100 G (Gauss) at a distance of 10 mm from the wall surface of the outer core portion 13, each design value is as follows. That is, the inner core portion 11 has a solid cylindrical shape with a radius (outer diameter) of 35 mm and a height of 25 mm, and is formed of a low permeability member having a magnetic property shown in FIG. 3 and a density of 2.7 g / cc. The outer core portion 13 has a cylindrical shape with an inner diameter of 46 mm, an outer diameter of 58 mm, and a height of 25 mm, and is formed of a high permeability member having a magnetic property shown in FIG. 4 and a density of 7.0 g / cc. The connecting core portions 14 and 14 are circular plates having a radius (outer diameter) of 58 mm and a thickness of 20 mm, and are formed of a high permeability member having a magnetic property shown in FIG. 4 and a density of 7.0 g / cc. The coil 12 has 19 turns and is accommodated in a space formed on the outer periphery of the inner core portion 11 with a length of 11 mm (= 46 mm−35 mm) in the radial direction.

  The volume of the reactor Dc1 of this comparative example is about 687 cc (= 58 mm × 58 mm × 3.14 × 65 mm). And in reactor Dc1 of this one comparative example, the leakage magnetic field was 18G at the maximum at a point 10 mm away from the wall surface of outer core portion 13 of reactor Dc1.

  Therefore, the volume of the reactor D1 of the one embodiment is reduced by about 26% (= (687−507) / 687 × 100) as compared with the reactor Dc1 of the one comparative example.

  As another comparative example, as shown in FIG. 10, the same structure as the reactor Dc <b> 1 of the comparative example shown in FIG. 9, the inner core portion 11, the outer core portion 13, and the connecting core portions 14, 14 are Similarly to the reactor D1 of one embodiment, the reactor Dc2 of another comparative example formed of a low magnetic permeability member has an inductance of 195 μH ± 15 μH with a reactor current in the range of 0 to 100 A, and leakage flux to the surroundings is small. When the design is such that the specification falls within 100 G (Gauss) at a distance of 10 mm from the wall surface of the outer core portion 13 of the reactor Dc2, the design values are as follows. That is, the inner core portion 11 has a solid cylindrical shape with a radius (outer diameter) of 35 mm and a height of 30 mm, and is formed of a low permeability member having a magnetic property shown in FIG. 3 and a density of 2.7 g / cc. The outer core portion 13 has a cylindrical shape with an inner diameter of 47 mm, an outer diameter of 71 mm, and a height of 30 mm, and is formed of a low permeability member having a magnetic property shown in FIG. 3 and a density of 2.7 g / cc. The connecting core portions 14 and 14 are discs having a radius (outer diameter) of 71 mm and a thickness of 45 mm, and are formed of a low permeability member having a magnetic property shown in FIG. 3 and a density of 2.7 g / cc. The coil 12 has 22 turns, and is accommodated in a space formed on the outer periphery of the inner core portion 11 with a length of 12 mm (= 47 mm−35 mm) in the radial direction.

  The volume of the reactor Dc2 of another comparative example is about 1900 cc (= 71 mm × 71 mm × 3.14 × 120 mm). In addition, in the reactor Dc2 of another comparative example, the leakage magnetic field was 98 G at the maximum at a point 10 mm away from the wall surface of the outer core portion 13 of the reactor Dc2.

  Therefore, the volume of the reactor D1 of the embodiment is reduced by about 73% (= (1900−507) / 1900 × 100) as compared with the reactor Dc2 of the other comparison example.

  In addition, each dimension in a reactor was calculated | required by FEM analysis. FEM analysis is a well-known analysis method, and is a method for obtaining the volume of a reactor in that case by optimization calculation when an inductance characteristic is given.

  In addition, although the high magnetic permeability member with the magnetic characteristic shown in FIG. 4 was used for the reactor D1 of the above-mentioned one Example, you may use the member with the magnetic characteristic shown in FIG. 11 as a high magnetic permeability member.

  FIG. 11 is a diagram showing the magnetic characteristics of another material having a relatively high density of magnetic materials. The horizontal axis in FIG. 11 indicates the magnetic flux density (T), and the vertical axis indicates the relative permeability.

  This high magnetic permeability member is a member having a density of 7.5 g / cc obtained by compacting iron powder by using, for example, a known conventional means, and is used for the third core portion 5 and the connecting core portions 6 and 6. It is done. As shown in FIG. 11, when the magnetic flux density is increased from the initial relative magnetic permeability of about 120, the magnetic flux density is about 0.35 T and the relative magnetic permeability is about 0.35 T. The profile gradually increases up to 230, and thereafter the relative permeability gradually decreases as the magnetic flux density increases. In the example shown in FIG. 11, the magnetic flux density at which the relative permeability becomes the initial relative permeability again as the magnetic flux density increases from the initial relative permeability is about 1.25T.

  FIG. 12 is a diagram illustrating the relationship between the density and magnetic flux density-relative permeability characteristics in a magnetic body containing iron powder.

  Further, in the above-described embodiment, although depending on the characteristics finally required for the reactor D, each of the first and second core portions 1 and 3 is considered from the viewpoint of generally required current-inductance characteristics. The initial relative permeability is preferably 2 to 20, and the initial relative permeability of the third core portion 5 and the connecting core portions 6 and 6 is preferably 50 to 250, respectively. With such a configuration, current-inductance characteristics generally required for a reactor, that is, current in which the inductance is substantially constant (including a case where the inductance is within a minute predetermined range) with respect to a change in current- Inductance characteristics can be realized.

  For example, the relationship between the density and the magnetic flux density-relative permeability characteristic in the magnetic body containing iron powder is the relationship shown in FIG. Here, ◆ indicates the case of density 7.5 g / cc, Δ indicates the case of density 7 g / cc, × indicates the case of density 6.5 g / cc, and * indicates the density 5.99 g. / Indicates a case of density of 4.98 g / cc (about 5 g / cc), and + indicates a density of 3.63 g / cc (about 3.6 g / cc). This case is shown.

  As described above, from the viewpoint of improving the current controllability, the profile member shown in FIG. 3 and the profile member shown in FIG. 4 are combined to improve the linearity of the BH curve in the entire reactor. Therefore, as can be seen from FIG. 12, a member having an initial relative permeability of about 2 to 20 (a member having a density of about 5 g / cc or less) has a BH curve similar to the BH curve shown in FIG. Since it is a substantially flat profile, it is preferable that each initial relative magnetic permeability of the 1st and 2nd core parts 1 and 3 is 2-20, respectively. As can be seen from FIG. 12, a member having an initial relative permeability of about 50 to 250 (a member having a density of about 6 g / cc or more) has a BH curve similar to the BH curve shown in FIG. The initial relative permeability of each of the third core portion 5 and the connecting core portions 6 and 6 is preferably 50 to 250 because the profile is obviously an upwardly convex profile.

  Moreover, from the viewpoint of preventing leakage magnetic flux leaking outside the reactor D, the initial relative magnetic permeability of the third core portion 5 and the connecting core portions 6 and 6 is preferably 150 to 250, respectively.

  In addition, although this embodiment demonstrated the reactor of the structure shown in FIG. 1, as above-mentioned, it is not limited to the reactor of the structure shown in FIG. 1, The reactor and structural of this structure shown in FIG. Although the configuration is different, the configuration equivalent to the magnetic circuit has the same effect as the reactor having the structure shown in FIG.

  FIG. 13 is a diagram illustrating a configuration of a reactor according to another embodiment. FIG. 13B is a vertical cross-sectional view, and FIG. 13A is a horizontal cross section when cut along XX shown in FIG. 13B. For example, as shown in FIG. 13, the first core portion 1 is composed of a pair of rod-shaped first core members 1A and 1B, and the first coil 2 is wound around each of the pair of first core members 1A and 1B. The second core portion 3 is composed of a pair of rod-shaped second core members 3A and 3B. The second core portion 3 is composed of a pair of rod-shaped second core members 3A and 3B. Each of the pair of second core members 3A and 3B is disposed outside the pair of coils 2A and 2B constituting the first coil 2, and the second coil 4 is electrically connected in series. A pair of coils 4A and 4B connected to each other, and one 4A of the pair of coils 4A and 4B constitutes the first coil 2 and one pair 2A of the coils 2A and 2B and a pair of second core members 3A. One of 3B and 3A The other 4B of the pair of coils 4A, 4B is wound so as to include the other 2B of the pair of coils 2A, 2B and the other 3B of the pair of second core members 3A, 3B. The connecting core portions 6, 6 are paired first core members 1 A, 1 B constituting the first core portion 1 and a pair of second core members 3 A constituting the second core portion 3. 3B are connected to each other.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

D, D1, Dc1, Dc2 Reactor 1 First core part 2 First coil 3 Second core part 4 Second coil 5 Third core part 6 Connecting core part

Claims (10)

A first core part;
A second core part;
A first coil wound only on the first core part;
A second coil wound to include at least both the first core part and the second core part;
A connecting core portion that connects the first and second core portions to each other;
The first coil and the second coil are electrically connected in series,
The magnetic permeability of the said 1st core part is lower than the magnetic permeability of the said connection core part, and the magnetic permeability of the said 2nd core part is lower than the magnetic permeability of the said connection core part. The reactor characterized by these. A third core portion;
The first coil is disposed outside the first core portion,
The second core portion is disposed outside the first coil,
The second coil is disposed outside the second core part,
The third core portion is disposed outside the second coil,
The connecting core portion connects the first to third core portions to each other so as to cover both end portions of the first and second coils,
The magnetic permeability of the first core portion is lower than the magnetic permeability of the third core portion and the connecting core portion, and the magnetic permeability of the second core portion is the third core portion and the connecting core portion. The reactor according to claim 1, wherein each of the reactors is lower than the magnetic permeability. The first core part is constituted by a pair of rod-shaped first core members,
The first coil is constituted by a pair of coils wound around each of the pair of first core members, and the pair of coils is electrically connected in series,
The second core portion is configured by a pair of rod-shaped second core members, and each of the pair of second core members is disposed outside the pair of coils that configure the first coil,
The second coil is composed of a pair of coils electrically connected in series, and one of the pair of coils constitutes the first coil and the pair of second cores. And the other of the pair of coils is wound so as to include the other of the pair of coils constituting the first coil and the other of the pair of second core members. Turned,
The connection core part connects all of the pair of first core members constituting the first core part and the pair of second core members constituting the second core part to each other. Item 1. The reactor according to Item 1. The reactor according to any one of claims 1 to 3, wherein the first and second core portions are formed by molding a mixture of a soft magnetic powder and a nonmagnetic powder. The reactor according to any one of claims 1 to 4, wherein the connecting core portion is formed by molding a soft magnetic powder. The reactor according to any one of claims 2, 4, and 5, wherein the third core portion is formed by molding a soft magnetic powder. The reactor according to any one of claims 1 to 6, wherein the first and second core portions are made of the same material. The reactor according to any one of claims 2, 4, 5, and 6, wherein the third core portion and the connecting core portion are made of the same material. Each initial relative permeability of the first and second core parts is 2 to 20, respectively.
The reactor according to any one of claims 1 to 8, wherein an initial relative magnetic permeability of the connecting core portion is 50 to 250, respectively. Each initial relative permeability of the first and second core parts is 2 to 20, respectively.
The initial relative magnetic permeability of the third core portion is 50 to 250, respectively. 2, Claim 4, Claim 5, Claim 7, Claim 8, and Claim 9. The reactor of any one of these.

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