Reactor, converter, and electric power conversion system

Abstract

To provide a reactor which can easily adjust an inductance and a heat dissipation without increasing the size.SOLUTION: In a reactor, a coil of which the number of winding parts is one, and a magnetic core are provided, an outer peripheral surface of each winding part contains a part contacted to an installation object of the reactor, and the magnetic core includes an E-shape like first core part, a T-shaped like second core part, and a gap part. The first core part is constructed by a compact of a composite material, and the second core part is constructed by a dust compact. The gap part is arranged between a first middle core part of the first core part and a second middle core part of the second core part in an inner part of each winding part. A length from the second end surface of each winding part to the gap part is 0.2 times or more and 0.49 times or less of the length of each winding part. A total volume of a volume of the first core part, a volume of the second core part, and a volume of the gap part is 50 cm3 or more and 500 cm3 or less.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a reactor, a converter, and a power conversion device. [Background technology]

[0002] The reactor of Patent Document 1 includes a coil, a magnetic core, a case, and a cooling pipe. The coil is formed by winding a wire in a spiral shape. The number of coils is one, and the coil is cylindrical. The magnetic core has an inner core part and an outer core part. The inner core part is disposed inside the coil. The outer core part covers both end faces of the inner core part and both end faces and the outer peripheral surface of the coil. The inner core part and the outer core part are made of different materials. Specifically, the inner core part is made of a powder compact, and the outer core part is made of a composite material compact. The case stores the combination of the coil and the magnetic core inside. The combination can be stored in the case by disposing the coil and the inner core part in the case, filling the case with raw materials of the composite material, and hardening the case. A refrigerant flows inside the cooling pipe. The cooling pipe is wound in a spiral shape in the circumferential direction of the case so as to be in contact with the outer peripheral surface of the case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-74062 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned combined body, the inner core portion and the outer core portion are made of different materials, so that the inductance can be easily adjusted. On the other hand, in the above-mentioned combined body, the coil and the inner core portion are embedded in the outer core portion, so that the heat dissipation is difficult to adjust. This is because the surface of the combined body is substantially made of only the constituent material of the outer core portion. Moreover, the combined body has low heat dissipation. This is because the outer core portion is made of a composite material and has a relatively low thermal conductivity. Therefore, the above-mentioned reactor enhances the heat dissipation performance of the combined body by storing the combined body in a case around which a cooling tube is wound. However, the reactor becomes large in size because the cooling tube is wound around the case.

[0005] An object of the present disclosure is to provide a reactor that allows easy adjustment of inductance and heat dissipation without increasing the size. Another object of the present disclosure is to provide a converter including the reactor. Still another object of the present disclosure is to provide a power conversion device including the converter. [Means for solving the problem]

[0006] The reactor of the present disclosure includes: A reactor including a coil and a magnetic core, The coil has a winding portion, The number of the windings is one, an outer circumferential surface of the winding portion includes a portion that contacts an object on which the reactor is to be installed, The magnetic core is An E-shaped first core portion and a T-shaped second core portion combined in the axial direction of the winding portion; a gap portion provided between the first core portion and the second core portion, the first core portion is composed of a first end core portion facing a first end face of the winding portion, a first middle core portion having a portion disposed inside the winding portion, and a first side core portion and a second side core portion disposed on the outer periphery of the winding portion so as to sandwich the first middle core portion, the first core portion being formed as an integral molded body of a composite material; the second core portion is composed of a powder compact formed integrally with a second end core portion facing a second end surface of the winding portion and a second middle core portion having a portion disposed inside the winding portion, a length of the winding portion in the second middle core portion along the axial direction is shorter than a length of the winding portion in the first middle core portion along the axial direction; the gap portion is disposed inside the winding portion, between the first middle core portion and the second middle core portion, a length from the second end surface to the gap portion is 0.2 times or more and 0.49 times or less the length of the winding portion, The total volume Va of the first core portion, the second core portion, and the gap portion is 50 cm 3 More than 500cm 3 The following is the result.

[0007] The converter of the present disclosure includes the reactor of the present disclosure.

[0008] The power conversion device of the present disclosure includes the converter of the present disclosure. Effect of the Invention

[0009] The reactor of the present disclosure allows easy adjustment of inductance and heat dissipation without increasing the size.

[0010] The converter and the power conversion device of the present disclosure have excellent heat dissipation properties without increasing in size. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view showing the entire reactor of the first embodiment. [Diagram 2] FIG. 2 is a schematic side view showing the entire reactor of the first embodiment. [Diagram 3] FIG. 3 is a schematic perspective view showing a state in which the reactor of the first embodiment is disassembled. [Figure 4] FIG. 4 is a schematic top view showing the entire reactor of the first embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing the power supply system of a hybrid vehicle. [Figure 6] FIG. 6 is a circuit diagram showing an example of a power conversion device including a converter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Description of the embodiments of the present disclosure First, the embodiments of the present disclosure will be listed and described.

[0013] (1) A reactor according to an embodiment of the present disclosure includes: A reactor including a coil and a magnetic core, The coil has a winding portion, The number of the windings is one, an outer circumferential surface of the winding portion includes a portion that contacts an object on which the reactor is to be installed, The magnetic core is An E-shaped first core portion and a T-shaped second core portion combined in the axial direction of the winding portion; a gap portion provided between the first core portion and the second core portion, the first core portion is composed of a first end core portion facing a first end face of the winding portion, a first middle core portion having a portion disposed inside the winding portion, and a first side core portion and a second side core portion disposed on the outer periphery of the winding portion so as to sandwich the first middle core portion, the first core portion being formed as an integral molded body of a composite material; the second core portion is composed of a powder compact formed integrally with a second end core portion facing a second end surface of the winding portion and a second middle core portion having a portion disposed inside the winding portion, a length of the winding portion in the second middle core portion along the axial direction is shorter than a length of the winding portion in the first middle core portion along the axial direction; the gap portion is disposed inside the winding portion, between the first middle core portion and the second middle core portion, a length from the second end surface to the gap portion is 0.2 times or more and 0.49 times or less the length of the winding portion, The total volume Va of the first core portion, the second core portion, and the gap portion is 50 cm 3 More than 500cm 3 The following is the result.

[0014] The inductance of the reactor is easy to adjust. In particular, the inductance of the reactor is easy to adjust without a large gap between the first core portion and the second core portion because the magnetic core is not made of a single material but is made of the first core portion made of a composite material compact and the second core portion made of a powder compact.

[0015] The above reactor has an easier heat dissipation adjustment than the conventional reactor described above. The magnetic core of the conventional reactor is formed by embedding a core part with a relatively high thermal conductivity in a core part with a relatively low thermal conductivity. In other words, the surface of the magnetic core of the conventional reactor is essentially made of a single material. In contrast, the above reactor has a magnetic core formed by combining a first core part and a second core part in the axial direction of the winding part, and therefore the surface of the magnetic core is made of different materials.

[0016] The above reactor has an improved heat dissipation property. This is because the above reactor includes a portion where the winding portion contacts the installation object, and thus can effectively dissipate heat from the coil through the installation object. In particular, the above reactor has an improved heat dissipation property compared to the above-mentioned conventional reactor. In the above-mentioned conventional reactor, the surface of the magnetic core is composed only of the core portion having a relatively low thermal conductivity as described above. In contrast, the above-mentioned reactor has a surface of the magnetic core that can include a surface composed of a powder compact having a relatively high thermal conductivity.

[0017] The reactor described above can be suitably used as a reactor cooled by a cooling member having a biased cooling performance. Of the first and second core parts, the second core part having a higher thermal conductivity is arranged on the side of the cooling member having a lower cooling performance, and the first core part having a lower thermal conductivity is arranged on the side of the cooling member having a higher cooling performance. This allows the first and second core parts to be cooled evenly, reducing the maximum temperature of the magnetic core.

[0018] The reactor is difficult to increase in size, because the heat dissipation of the reactor is easily adjusted and easily increased as described above, and therefore, unlike the conventional reactor, a cooling pipe is not required.

[0019] The reactor described above has only one winding part, and therefore the installation area in the direction perpendicular to the axial direction can be made smaller than in the case where multiple winding parts are arranged in parallel in a direction perpendicular to the axial direction of the winding part.

[0020] The reactor is easy to manufacture, since the reactor can be manufactured by simply assembling the first and second core portions, which are fabricated in advance, to the coil.

[0021] The reactor has low loss. This is because the length of the second middle core portion is shorter than the length of the first middle core portion, and therefore the proportion of the green compact having a larger loss than the green compact of the composite material is small. In addition, the gap portion of the reactor is disposed inside the winding portion, and the length from the second end face to the gap portion is 0.2 times or more the length of the winding portion, and therefore leakage magnetic flux is unlikely to enter the winding portion. This is because it is easy to reduce eddy current loss generated in the winding portion. Furthermore, the length from the second end face to the gap portion is 0.49 times or less the length of the winding portion, and therefore the proportion of the green compact of the composite material having a lower loss than the green compact can be increased inside the winding portion. And, the reactor can reduce the maximum temperature of the magnetic core as described above.

[0022] The reactor can suppress problems such as the influence of leakage magnetic flux on peripheral devices, because the gap portion of the reactor is disposed inside the winding portion, and the length from the second end face to the gap portion is 0.2 times or more the length of the winding portion, which makes it easy to suppress leakage of magnetic flux to the outside of the winding portion.

[0023] The second core part having a T-shape is easier to manufacture than the second core part having an E-shape. Therefore, the second core part having a T-shape is easier to manufacture with high precision than the second core part having an E-shape. Therefore, the second core part having a T-shape is less likely to have an unnecessary gap when combined with the first core part than the second core part having an E-shape.

[0024] The total volume of the reactor is 50 cm 3 More than 500cm 3 The above-mentioned characteristics make the converter suitable for use in a converter of an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

[0025] Generally, the larger the volume of a reactor, the easier it is to generate heat and the harder it is to dissipate heat. However, since the reactor is easy to increase heat dissipation as described above, when the total volume Va is 50 cm 3 Even if the temperature is more than this, heat generation is easily suppressed.

[0026] (2) As one embodiment of the above reactor, The ratio of the volume of the second core portion to the total volume Va is preferably 25% or more and 40% or less.

[0027] If the ratio is 25% or more, the heat dissipation performance of the reactor is likely to be high. If the ratio is 40% or less, the loss of the reactor is likely to be reduced.

[0028] (3) As one embodiment of the above reactor, The ratio of the volume of the second middle core portion to the total volume of the first middle core portion, the second middle core portion, and the gap portion may be 15% or more and 49% or less.

[0029] If the ratio is 15% or more, the heat dissipation performance of the reactor is likely to be high. If the ratio is 49% or less, the loss of the reactor is likely to be reduced.

[0030] (4) As one embodiment of the reactor, The ratio of the thickness of the gap portion to the total length of the length of the first middle core portion, the length of the second middle core portion, and the thickness of the gap portion may be 0.001 or more and 0.1 or less.

[0031] If the ratio is 0.001 or more, a predetermined inductance is easily ensured. If the ratio is 0.1 or less, leakage flux is small, and the effect of reducing eddy current loss is easily increased.

[0032] (5) As one embodiment of the above reactor, The thickness of the gap portion is preferably 0.1 mm or more and 2 mm or less.

[0033] If the thickness is 0.1 mm or more, a predetermined inductance is easily ensured, and if the thickness is 2 mm or less, leakage flux is small, and the effect of reducing eddy current loss is easily increased.

[0034] (6) As one embodiment of the reactor, It is preferable to provide a molded resin portion that covers at least a portion of the magnetic core and that constitutes the gap portion.

[0035] In the reactor, since the gap portion is formed of the molded resin portion, it is easy to maintain the interval between the end face of the first middle core portion and the end face of the second middle core portion, and the magnetic core covered by the molded resin portion is easy to protect from the external environment.

[0036] In the above reactor, it is easy to configure the gap portion with a part of the molded resin portion. The reason is as follows. The gap portion configured with a part of the molded resin portion is formed as follows. An assembly is prepared by combining a coil and a magnetic core. The constituent material of the molded resin portion is spread from the outside of the assembly toward the inside of the winding portion between the end faces of the first middle core portion and the second middle core portion. When the total volume Va is 50 cm 3 Even if the length from the second end face to the gap portion is 0.49 times or less the length of the winding portion, the constituent material of the molded resin portion can be easily distributed between the end faces.

[0037] (7) As one embodiment of the reactor, It may be useful to configure a converter for an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

[0038] The reactor is suitable for forming the converter.

[0039] (8) As one embodiment of the reactor, The powder compact is a compact of a raw material powder containing a soft magnetic powder, The content of the soft magnetic powder in the powder compact may be 85% by volume or more and 99% by volume or less.

[0040] The magnetic properties of the above-mentioned powder compact can be improved more easily than those of a composite material compact.

[0041] (9) As one embodiment of the reactor, The composite material compact is a compact in which soft magnetic powder is dispersed in a resin, The content of the soft magnetic powder in the composite material compact may be 20% by volume or more and 80% by volume or less.

[0042] The magnetic properties of the composite material compact can be adjusted more easily than with a powder compact, and it is also easier to form the composite material into a complex shape.

[0043] (10) A converter according to an embodiment of the present disclosure includes: The reactor includes the reactor according to any one of (1) to (9) above.

[0044] Since the converter includes the reactor, it does not become large in size, has excellent heat dissipation properties, and has low loss.

[0045] (11) A power conversion device according to an embodiment of the present disclosure, The device is equipped with the converter (10) described above.

[0046] The power conversion device includes the converter, and therefore has excellent heat dissipation properties and low loss without being large in size.

[0047] Details of the embodiments of the present disclosure DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the embodiments of the present disclosure will be described below with reference to the drawings. In the drawings, the same reference numerals indicate the same objects.

[0048] First Embodiment [Reactor] A reactor 1 of the first embodiment will be described with reference to Fig. 1 to Fig. 4. The reactor 1 includes a coil 2 and a magnetic core 3. The coil 2 has a winding portion 21. The number of the winding portion 21 is one. One of the features of the reactor 1 of this embodiment is that it satisfies the following requirements (a) to (f).

[0049] As shown in FIG. 2(a), outer circumferential surface 25 of winding portion 21 includes a portion that comes into contact with target 100 on which reactor 1 is to be installed. (b) As shown in FIG. 1, the magnetic core 3 has an E-shaped first core portion 3f and a T-shaped second core portion 3s combined in the axial direction of the winding portion 21, and a gap portion 3g provided between the first core portion 3f and the second core portion 3s. (c) The first core portion 3f is composed of a molded body of a composite material, and the second core portion 3s is composed of a powder molded body. (d) The first middle core portion 31f included in the first core portion 3f and the second middle core portion 31s included in the second core portion 3s have specific lengths. (e) The gap portion 3g is located at a specific location. (f) The volume of the magnetic core 3 is a specific size.

[0050] Each component will be described in detail below. For convenience of explanation, the coil 2 is indicated by a two-dot chain line in Fig. 4. In the following explanation, a first direction D1, a second direction D2, and a third direction D3 defined as follows may be used. The first direction D1 is a direction along the axial direction of the winding portion 21. The second direction D2 is a direction along the parallel arrangement direction of a first middle core portion 31f, a first side core portion 321, and a second side core portion 322, which will be described later. The third direction D3 is a direction perpendicular to both the first direction D1 and the second direction D2.

[0051] [coil] As shown in Fig. 3, the coil 2 has a hollow winding portion 21. The winding portion 21 is formed by spirally winding one wire without any joints. The number of winding portions 21 is one. Since the reactor 1 of this embodiment has only one winding portion 21, the length along the second direction D2 can be made shorter than when multiple winding portions are arranged in parallel in a direction perpendicular to the axial direction of the winding portion.

[0052] The shape of the winding part 21 is a rectangular cylinder. The rectangle includes a rectangle and a square. The end face shape of the winding part 21 in this embodiment is a rectangular frame shape. Since the shape of the winding part 21 is a rectangular cylinder, it is easy to increase the contact area between the winding part 21 and the installation target 100 compared to when the winding part 21 is a circular cylinder with the same cross-sectional area. Therefore, the reactor 1 is easy to dissipate heat to the installation target 100 through the winding part 21. In addition, the winding part 21 is easy to stably install on the installation target 100. An example of the installation target 100 is a cooling base or the inner bottom surface of a case described later. The corners of the winding part 21 are rounded. Unlike this embodiment, the shape of the winding part 21 may be a circular cylinder. The circle includes a perfect circle and an ellipse.

[0053] The winding may be a known winding. The winding in this embodiment uses a coated rectangular wire. The conductor wire of the coated rectangular wire is made of a rectangular copper wire. The insulating coating of the coated rectangular wire is made of enamel. The winding portion 21 is made of an edgewise coil in which the coated rectangular wire is wound edgewise.

[0054] The first end 21a and the second end 21b of the winding portion 21 are respectively extended toward the outer periphery of the winding portion 21 at the first end side and the second end side in the axial direction of the winding portion 21 in this embodiment. Although not shown in the figure, the insulating coating of the first end 21a and the second end 21b is stripped to expose the conductor wire. As shown in FIG. 2, the exposed conductor wire is drawn out to the outside of the molded resin portion 4, which will be described later in this embodiment. A terminal member is connected to the exposed conductor wire. The terminal member is not shown in the figure. An external device is connected to the coil 2 via this terminal member. The external device is not shown in the figure. An example of the external device is a power source that supplies power to the coil 2.

[0055] The outer peripheral surface 25 of the winding portion 21 has a portion that contacts the installation target 100 of the reactor 1. Therefore, the reactor 1 is easy to improve the heat dissipation. The outer peripheral surface 25 has a portion that protrudes in the third direction D3 beyond the magnetic core 3. That is, the length of the winding portion 21 along the third direction D3 is longer than the length of the magnetic core 3 along the third direction D3. In this embodiment, since the shape of the winding portion 21 is a rectangular tube, the outer peripheral surface 25 of the winding portion 21 has four flat surfaces. In this embodiment, one of the four flat surfaces is a portion that contacts the installation target 100. Therefore, the winding portion 21 can secure a sufficient contact area with the installation target 100. Therefore, the reactor 1 is easy to further improve the heat dissipation. In this embodiment, the contact portion of the winding portion 21 is exposed from the molded resin portion 4 described later. Therefore, the heat of the coil 2 is easy to be released through the installation target 100.

[0056] [Magnetic core] As shown in FIG. 1, the magnetic core 3 is an assembly in which the first core portion 3f and the second core portion 3s are combined in the first direction D1. A gap portion 3g, which will be described later, is provided between the first core portion 3f and the second core portion 3s. Since the magnetic core 3 can be constructed by combining the first core portion 3f and the second core portion 3s in the first direction D1, the reactor 1 has excellent manufacturing workability. The combination of the first core portion 3f and the second core portion 3s is an ET type. This combination makes it easier to adjust the inductance and heat dissipation. The first core portion 3f is made of a molded body of a composite material, which will be described later. The second core portion 3s is made of a powder compact, which will be described later.

[0057] The total volume Va of the first core portion 3f, the second core portion 3s, and the gap portion 3g is 50 cm 3 More than 500cm 3 The total volume V is 50 cm 3 More than 500cm 3 The reactor 1 having the above-mentioned volume Va is suitable for a converter of an electric vehicle, a hybrid vehicle, or a fuel cell vehicle. Since the winding portion 21 has a portion that contacts the installation target 100 and the second core portion 3s is made of a powder compact, the total volume Va is 50 cm 3 Even if the total volume Va is more than 500 cm, the heat of the magnetic core 3 is easily dissipated. 3 By keeping the total volume Va at 60 cm or less, the reactor 1 is unlikely to become excessively large. 3 More than 400cm 3 Less than 70cm, especially 3 More than 300cm 3 The volume of the gap portion 3g is the volume of a space surrounded by the end face of the first middle core portion 31f, the end face of the second middle core portion 31s, and a virtual outer circumferential surface. The virtual outer circumferential surface is an outer circumferential surface obtained by extending the outer circumferential surface of the first middle core portion 31f in the first direction D1.

[0058] (First core part) The planar shape of the first core portion 3f is E-shaped as shown in FIG. 4. The planar shape of the first core portion 3f refers to the shape of the first core portion 3f when viewed from the third direction D3. The concept of the planar shape is the same for the second core portion 3s described later. The first core portion 3f has a first end core portion 33f, a first middle core portion 31f, a first side core portion 321, and a second side core portion 322. The first end core portion 33f faces a first end surface of the winding portion 21. Facing means that the first end core portion 33f and the first end surface of the winding portion 21 face each other. The first middle core portion 31f has a portion that is disposed inside the winding portion 21. The first side core portion 321 and the second side core portion 322 are disposed facing each other so as to sandwich the first middle core portion 31f. The first side core portion 321 and the second side core portion 322 are disposed on the outer periphery of the winding portion 21.

[0059] As shown in Fig. 3, the first core portion 3f is an integrally molded body of a first end core portion 33f, a first middle core portion 31f, a first side core portion 321, and a second side core portion 322. The first end core portion 33f connects the first middle core portion 31f, the first side core portion 321, and the second side core portion 322. The first side core portion 321 and the second side core portion 322 are provided at both ends of the first end core portion 33f. The first middle core portion 31f is provided in the center of the first end core portion 33f. The first core portion 3f is composed of a molded body of a composite material described later.

[0060] In this embodiment, the first end core portion 33f has a thin rectangular column shape. The first middle core portion 31f has a shape corresponding to the inner peripheral shape of the winding portion 21. The first middle core portion 31f has a quadrangular column shape in this embodiment. The corners of the first middle core portion 31f are shown as angular in FIG. 3, but are rounded to fit the inner peripheral surface of the corners of the winding portion 21. The first side core portion 321 and the second side core portion 322 have the same shape. In this embodiment, the first side core portion 321 and the second side core portion 322 have a thin rectangular column shape.

[0061] The sum of the cross-sectional area of ​​the first side core portion 321 and the cross-sectional area of ​​the second side core portion 322 is the same as the cross-sectional area of ​​the first middle core portion 31f and the cross-sectional area of ​​the second middle core portion 31s. The cross-sectional area here refers to the cross-sectional area of ​​a cross section perpendicular to the first direction D1.

[0062] As shown in FIG. 4, the length L1f of the first middle core portion 31f along the first direction D1 is shorter than the length of the wound portion 21 along the first direction D1. The length of the wound portion 21 along the first direction D1 is the length along the first direction D1 between the first end face and the second end face of the wound portion 21. When there is a gap between the turns of the wound portion 21, the length of the wound portion 21 along the first direction D1 includes the length of the gap between the turns. The length of the first middle core portion 31f along the second direction D2 is longer than each of the lengths of the first side core portion 321 along the second direction D2 and the second side core portion 322 along the second direction D2. As shown in FIG. 1, the length of the first middle core portion 31f along the third direction D3 is the same as each of the lengths of the first side core portion 321 along the third direction D3 and the second side core portion 322 along the third direction D3.

[0063] As shown in Fig. 4, a length L21f of the first side core portion 321 along the first direction D1 and a length L22f of the second side core portion 322 along the first direction D1 are the same. The lengths L21f and L22f are longer than the length L1f and longer than the length of the winding portion 21 along the first direction D1. The length of the first side core portion 321 along the second direction D2 and the length of the second side core portion 322 along the second direction D2 are the same. As shown in Fig. 1, the length of the first side core portion 321 along the third direction D3 and the length of the second side core portion 322 along the third direction D3 are the same.

[0064] (Second core part) The second core portion 3s has a T-shape in plan view as shown in Fig. 4. The second core portion 3s has a second end core portion 33s and a second middle core portion 31s. The second end core portion 33s faces a second end surface of the wound portion 21. Facing means that the second end core portion 33s and the second end surface of the wound portion 21 face each other. The second middle core portion 31s has a portion that is disposed inside the wound portion 21.

[0065] As shown in FIG. 3, the second core portion 3s is a molded body in which the second end core portion 33s and the second middle core portion 31s are integrated. The second middle core portion 31s is provided at the center of the second end core portion 33s. The second core portion 3s is composed of a powder compact, which will be described later. A powder compact having a T-shape is easier to manufacture than a powder compact having an E-shape. Therefore, a powder compact having a T-shape is easier to manufacture with high accuracy than a powder compact having an E-shape. Therefore, when the second core portion 3s having a T-shape is combined with the first core portion 3f, an unnecessary gap is less likely to be formed than when the second core portion 3s has an E-shape.

[0066] The shape of the second end core portion 33s is the same as the shape of the first end core portion 33f. That is, the second end core portion 33s is a thin rectangular column. The shape of the second middle core portion 31s is a quadrangular column. The corners of the second middle core portion 31s are rounded to fit the inner circumferential surface of the corners of the winding portion 21.

[0067] As shown in Fig. 4, the length L1s of the second middle core portion 31s along the first direction D1 is shorter than the length L1f. The sum of the length L1s and the length L1f is shorter than each of the lengths L21f and L22f. The length of the second middle core portion 31s along the second direction D2 is the same as the length of the first middle core portion 31f along the second direction D2. As shown in Fig. 1, the length of the second middle core portion 31s along the third direction D3 is the same as the length of the first middle core portion 31f along the third direction D3.

[0068] As shown in FIG. 4, the length L3s of the second end core portion 33s along the first direction D1 is the same as the length L3f of the first end core portion 33f along the first direction D1. The length of the second end core portion 33s along the second direction D2 is the same as the length of the first end core portion 33f along the second direction D2. The length of the second end core portion 33s along the second direction D2 is longer than the length of the wound portion 21 along the second direction D2. As shown in FIG. 1, the length of the second end core portion 33s along the third direction D3 is the same as the length of the first end core portion 33f along the third direction D3. As shown in FIG. 2, the length of the second end core portion 33s along the third direction D3 is shorter than the length of the wound portion 21 along the third direction D3. As shown in FIG. 1, the length of the second end core portion 33s along the third direction D3 is the same as the length of the second middle core portion 31s along the third direction D3.

[0069] An example of the volume ratio Vps calculated by (volume Vs / total volume Va)×100 is 25% or more and 40% or less. The volume Vs is the volume of the second core portion 3s. As described above, the total volume Va is the total volume of the first core portion 3f, the second core portion 3s, and the gap portion 3g. If the volume ratio Vps is 25% or more, the heat dissipation of the reactor 1 is likely to be improved. If the volume ratio Vps is 40% or less, the loss of the reactor 1 is likely to be reduced. The volume ratio Vps is furthermore 27% or more and 38% or less, and particularly 29% or more and 36% or less.

[0070] An example of the volume ratio Vpm calculated by (volume Vms / total volume Vma)×100 is 15% or more and 49% or less. The volume Vms is the volume of the second middle core portion 31s. The total volume Vma is the total volume of the first middle core portion 31f, the second middle core portion 31s, and the gap portion 3g. If the ratio Vpm is 15% or more, the heat dissipation of the reactor 1 is likely to be improved. If the ratio Vpm is 49% or less, the loss of the reactor 1 is likely to be reduced. The ratio Vpm is furthermore 20% or more and 40% or less, and particularly 25% or more and 35% or less.

[0071] The first core portion 3f and the second core portion 3s are combined so that the end faces of the first side core portion 321 and the second side core portion 322 are in contact with the end face of the second end core portion 33s. A gap is provided between the end face of the first middle core portion 31f and the end face of the second middle core portion 31s. A gap portion 3g, which will be described later, is provided between the end face of the first middle core portion 31f and the end face of the second middle core portion 31s.

[0072] The composite material molded body constituting the first core portion 3f is a molded body in which soft magnetic powder is dispersed in resin. The composite material molded body is obtained by filling a mold with a fluid material in which soft magnetic powder is dispersed in unsolidified resin, and solidifying the resin. The composite material molded body allows easy adjustment of the content of soft magnetic powder in the resin. Therefore, the magnetic properties of the composite material molded body are easy to adjust. Furthermore, the composite material molded body is easy to form even complex shapes compared to pressed powder molded bodies. An example of the content of soft magnetic powder in the composite material molded body is 20 volume % or more and 80 volume % or less. An example of the content of resin in the composite material molded body is 20 volume % or more and 80 volume % or less. These contents are values ​​when the composite material molded body is 100 volume %.

[0073] The powder compact constituting the second core portion 3s is a compact obtained by compressing and molding soft magnetic powder. Compared to a composite material compact, the powder compact can have a higher ratio of soft magnetic powder in the core portion. Therefore, the powder compact is easy to improve magnetic properties. Examples of magnetic properties include relative permeability and saturation magnetic flux density. Also, compared to a composite material compact, the powder compact has a smaller amount of resin and a larger amount of soft magnetic powder, and therefore has excellent heat dissipation properties. An example of the content of magnetic powder in the powder compact is 85 volume % or more and 99 volume % or less. This content is the value when the powder compact is 100 volume %.

[0074] Examples of the particles constituting the soft magnetic powder include soft magnetic metal particles, coated particles, and soft magnetic nonmetal particles. The coated particles include a soft magnetic metal particle and an insulating coating provided on the outer periphery of the soft magnetic metal particle. The soft magnetic metal includes pure iron or an iron-based alloy. An example of the iron-based alloy is an Fe-Si alloy or an Fe-Ni alloy. An example of the insulating coating is a phosphate. An example of the soft magnetic nonmetal is a ferrite.

[0075] An example of the resin of the composite material molded body is a thermosetting resin or a thermoplastic resin. An example of the thermosetting resin is an epoxy resin, a phenolic resin, a silicone resin, a urethane resin, etc. An example of the thermoplastic resin is a polyphenylene sulfide resin, a polyamide resin, a liquid crystal polymer, a polyimide resin, a fluororesin, etc. An example of the polyamide resin is Nylon 6, Nylon 66, Nylon 9T, etc.

[0076] The composite material compact may contain a ceramic filler. Examples of the ceramic filler include alumina and silica. The ceramic filler contributes to improving heat dissipation and electrical insulation.

[0077] The content of soft magnetic powder in the composite material compact and the content of soft magnetic powder in the powder compact are considered to be equivalent to the area ratio of the soft magnetic powder in the cross section of the compact. The content of soft magnetic powder in the compact is determined as follows. The cross section of the compact is observed with a SEM (scanning electron microscope) to obtain an observation image. The cross section of the compact is any cross section. The magnification of the SEM is 200 times or more and 500 times or less. At least 10 observation images are obtained. The total cross section is 0.1 cm2. 2 That is all. One observation image may be acquired per cross section, or multiple observation images may be acquired per cross section. Each acquired observation image is subjected to image processing to extract particle contours. Image processing includes, for example, binarization processing. The area ratio of soft magnetic particles in each observation image is calculated, and the average value of the area ratios is obtained. The average value is regarded as the content of soft magnetic powder.

[0078] As described above, the first core portion 3f is made of a composite material molded body, and the second core portion 3s is made of a powder compact. Since the first core portion 3f is made of a composite material molded body and the second core portion 3s is made of a powder compact, it is easy to adjust the inductance without using the long gap portion 3g, and it is also easy to adjust the heat dissipation. Furthermore, since the second core portion 3s of the reactor 1 is made of a powder compact with a relatively high thermal conductivity, it is easy to improve the heat dissipation.

[0079] (Gap part) The gap portion 3g is disposed inside the winding portion 21. The gap portion 3g is disposed between an end face of the first middle core portion 31f and an end face of the second middle core portion 31s. Since the gap portion 3g is disposed inside the winding portion 21, leakage magnetic flux is less likely to enter the winding portion 21 than when the gap portion 3g is disposed outside the winding portion 21. Therefore, it is easier to reduce eddy current loss generated in the winding portion 21. The gap portion 3g is made of a member made of a material having a smaller relative magnetic permeability than the first core portion 3f and the second core portion 3s. The gap portion 3g in this embodiment is made of a part of the molded resin portion 4 described later.

[0080] An example of the ratio of the thickness of the gap portion 3g to the total length of the length L1f, the length L1s, and the thickness of the gap portion 3g is 0.001 or more and 0.1 or less. The thickness of the gap portion 3g is the length Lg of the gap portion 3g along the first direction D1. If the ratio is 0.001 or more, it is easy to ensure a predetermined inductance. If the ratio is 0.1 or less, the leakage flux is small and the effect of reducing eddy current loss is easy to be increased. The ratio is further 0.01 or more and 0.08 or less, particularly 0.02 or more and 0.06 or less.

[0081] An example of the thickness of the gap portion 3g is 0.1 mm or more and 2 mm or less. If the thickness is 0.1 mm or more, it is easy to ensure a predetermined inductance. If the thickness is 2 mm or less, leakage flux is small and the effect of reducing eddy current loss is likely to be high. The thickness is further 0.3 mm or more and 1.75 mm or less, and particularly 0.5 mm or more and 1.5 mm or less.

[0082] An example of the length Le along the first direction D1 from the second end face of the winding portion 21 to the gap portion 3g is 0.2 to 0.49 times the length along the first direction D1 of the winding portion 21. The length Le is the length along the first direction D1 between the position closest to the second end face in the gap portion 3g and the second end face.

[0083] When the length Le is 0.2 times or more the length of the winding portion 21 in the first direction D1, leakage flux is less likely to enter the winding portion 21. This makes it easier to reduce eddy current loss generated in the winding portion 21. The closer the length Le is to 0.5 times the length of the winding portion 21 in the first direction D1, that is, the closer the position of the gap portion 3g is to the center of the winding portion 21 in the first direction D1, the greater the effect of reducing eddy current loss.

[0084] By making the length Le 0.49 times or less the length of the winding portion 21 along the first direction D1, the ratio of the compact made of the composite material, which has lower loss than the powder compact, can be increased, and therefore the reactor 1 has low loss. Furthermore, by making the length Le 0.49 times or less the length of the winding portion 21 along the first direction D1, it is easy to fabricate the gap portion 3g constituted by a part of the molded resin portion 4. The gap portion 3g constituted by a part of the molded resin portion 4 is formed as follows. An assembly is prepared by combining the coil 2 and the magnetic core 3. The constituent material of the molded resin portion 4 is spread from the outside of the assembly toward the space between the end face of the first middle core portion 31f and the end face of the second middle core portion 31s inside the winding portion 21. By making the length Le 0.49 times or less the length of the winding portion 21 along the first direction D1, the total volume Va is reduced to 50 cm. 3 Even in the above case, it is easy to spread the constituent material of the molded resin portion 4 between the above-mentioned end faces. The shorter the length Le, the easier it is to spread the constituent material of the molded resin portion 4 between the above-mentioned end faces.

[0085] The length Le is further 0.2 to 0.4 times the length of the wound portion 21 in the first direction D1, and particularly 0.25 to 0.375 times the length of the wound portion 21 in the first direction D1.

[0086] [Molded resin part] 1, the molded resin part 4 covers at least a part of the magnetic core 3 and forms a gap part 3g. The molded resin part 4 may cover the outer periphery of the magnetic core 3 but not the outer periphery of the coil 2, or may cover both the outer periphery of the magnetic core 3 and the outer periphery of the coil 2. For convenience of explanation, the molded resin part 4, which will be described later, is omitted in FIG. 4.

[0087] As shown in FIG. 2, the molded resin part 4 in this embodiment covers the outer periphery of the assembly of a part of the coil 2 and the magnetic core 3. Therefore, the assembly is substantially protected from the external environment. In this embodiment, the flat surface of the outer periphery of the coil 2 on the side of the installation target is exposed from the molded resin part 4. The outer periphery of the coil 2 except for the flat surface on the side of the installation target is covered by the molded resin part 4. The entire outer periphery of the magnetic core 3 is covered by the molded resin part 4. The molded resin part 4 is provided between the winding part 21 and the first middle core part 31f, between the winding part 21 and the second middle core part 31s, and between the end face of the first middle core part 31f and the end face of the second middle core part 31s. The molded resin part 4 integrates the coil 2 and the magnetic core 3. An example of the resin of the molded resin part 4 is the same resin as the resin of the above-mentioned composite material compact. The resin of the molded resin part 4 may contain a ceramic filler, as in the composite material compact.

[0088] [others] Although not shown, the reactor 1 may include at least one of a case, an adhesive layer, and a holding member. The case houses the assembly of the coil 2 and the magnetic core 3 inside. The assembly in the case may be embedded with a sealing resin portion. The case is placed on a cooling base or the like. The adhesive layer fixes the assembly to the cooling base or the inner bottom surface of the case, or fixes the case to the cooling base or the like. The holding member is provided between the coil 2 and the magnetic core 3, and ensures insulation between the coil 2 and the magnetic core 3.

[0089] [Effects of the First Embodiment] The reactor 1 of this embodiment can provide the following effects.

[0090] In the reactor 1, the inductance can be easily adjusted without increasing the thickness of the gap portion 3g because the magnetic core 3 is not made of a single material but is made up of the first core portion 3f made of a composite material compact and the second core portion 3s made of a powder compact.

[0091] The reactor 1 has an easy-to-improve heat dissipation property. This is because the winding part 21 includes a portion that contacts the installation target 100, and thus the heat of the coil 2 can be effectively dissipated through the installation target 100. In addition, this is because the surface of the magnetic core 3 can include a surface that is made of a powder compact with a relatively high thermal conductivity.

[0092] The reactor 1 can be suitably used as a reactor cooled by a cooling member having a biased cooling performance. The second core portion 3s having a high thermal conductivity is arranged on the side of the cooling member having a low cooling performance, and the first core portion 3f having a low thermal conductivity is arranged on the side of the cooling member having a high cooling performance. As a result, the first core portion 3f and the second core portion 3s are cooled evenly, and the maximum temperature of the magnetic core 3 is reduced.

[0093] It is difficult to increase the size of the reactor 1. This is because, as described above, the heat dissipation performance of the reactor 1 is easily adjusted and easily increased, and therefore, unlike the conventional reactor described above, there is no need to provide a cooling pipe.

[0094] The reactor 1 has low loss. This is because the length L1s is shorter than the length L1f, and therefore the proportion of the green compacts having a larger loss than the green compacts of the composite material is small. In addition, the gap portion 3g is disposed inside the winding portion 21, and the length Le is 0.2 times or more the length of the winding portion 21, and therefore the leakage flux is unlikely to enter the winding portion 21. Therefore, it is easy to reduce the eddy current loss generated in the winding portion 21. Furthermore, the length Le is 0.49 times or less the length of the winding portion 21, and therefore the proportion of the green compacts of the composite material having a lower loss than the green compacts can be increased inside the winding portion 21. And, as described above, the maximum temperature of the magnetic core 3 is reduced.

[0095] Reactor 1 can suppress problems such as the influence of leakage magnetic flux on peripheral devices. This is because gap 3g is disposed inside winding portion 21 and has length Le that is 0.2 times or more the length of winding portion 21, which makes it easy to suppress leakage of magnetic flux to the outside of winding portion 21.

[0096] In the reactor 1, the gap 3g is easily formed in a part of the molded resin portion 4. The length Le is 0.49 times or less the length of the winding portion 21. In other words, the gap that becomes the gap 3g is close to the second end face of the winding portion 21. Therefore, when the total volume Va is 50 cm 3 Even in the above case, the constituent material of the molded resin portion can be easily spread toward the space inside the winding portion 21 between the end face of the first middle core portion 31f and the end face of the second middle core portion 31s.

[0097] Second Embodiment [Converter / Power Conversion Device] The reactor 1 of the first embodiment can be used for applications that satisfy the following energization conditions. Examples of the energization conditions include a maximum DC current of about 100 A to 1000 A, an average voltage of about 100 V to 1000 V, and a usage frequency of about 5 kHz to 100 kHz. The reactor 1 of the first embodiment can be used as a component of a converter mounted on a vehicle 1200, typically an electric vehicle, a hybrid vehicle, or a fuel cell vehicle, or as a component of a power conversion device including the converter.

[0098] 5, the vehicle 1200 includes a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and a motor 1220 that is driven by power supplied from the main battery 1210 and used for traveling. The motor 1220 is typically a three-phase AC motor that drives wheels 1250 during traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 includes an engine 1300 in addition to the motor 1220. Although FIG. 5 shows an inlet as a charging point for the vehicle 1200, a form including a plug may also be used.

[0099] The power conversion device 1100 includes a converter 1110 connected to a main battery 1210, and an inverter 1120 connected to the converter 1110 and performing mutual conversion between direct current and alternating current. The converter 1110 shown in this example boosts the input voltage of the main battery 1210, which is about 200V to 300V, to about 400V to 700V when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, the converter 1110 lowers the input voltage output from the motor 1220 via the inverter 1120 to a direct current voltage suitable for the main battery 1210, and charges the main battery 1210. The input voltage is a direct current voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC boosted by the converter 1110 into a predetermined AC and supplies it to the motor 1220. During regeneration, the inverter 1120 converts the AC output from the motor 1220 into DC and outputs it to the converter 1110.

[0100] As shown in FIG. 6, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly switching on and off. The conversion of the input voltage means stepping up and down the voltage here. The switching elements 1111 include power devices such as field effect transistors and insulated gate bipolar transistors. The reactor 1115 has a function of smoothing the change when the current increases or decreases due to the switching operation by utilizing the property of a coil that prevents the change in the current flowing through the circuit. The reactor 1 of the first embodiment is included as the reactor 1115. By including the reactor 1 that has excellent heat dissipation properties without being large and has low loss, the power conversion device 1100 and the converter 1110 can be expected to be miniaturized, have improved heat dissipation properties, and have low loss.

[0101] In addition to the converter 1110, the vehicle 1200 includes a converter 1150 for a power supply device connected to the main battery 1210, and a converter 1160 for an auxiliary power supply connected to a sub-battery 1230 serving as a power source for the auxiliary devices 1240 and the main battery 1210 to convert the high voltage of the main battery 1210 to a low voltage. The converter 1110 typically performs DC-DC conversion, while the converter 1150 for a power supply device and the converter 1160 for an auxiliary power supply perform AC-DC conversion. Some of the converters 1150 for a power supply device perform DC-DC conversion. The reactors of the converter 1150 for a power supply device and the converter 1160 for an auxiliary power supply may have the same configuration as the reactor 1 of the first embodiment, and may be reactors whose size, shape, and the like are appropriately changed. The reactor 1 of the first embodiment may also be used as a converter that converts input power and that performs only step-up or step-down.

[0102] The present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0103] 1 Reactor 2 coils, 21 winding portion, 21a first end portion, 21b second end portion, 25 Outer surface 3 magnetic core, 3f first core part, 3s second core part 31f First Middle Core Section, 31s Second Middle Core Section 321 first side core portion, 322 second side core portion 33f first end core part, 33s second end core part 3g Gap section 4 Molded resin part L1f, L1s, L21f, L22f, L3f, L3s, Le length D1 first direction, D2 second direction, D3 third direction 100 Installation targets 1100 Power Converter, 1110 Converter 1111 switching element, 1112 drive circuit, 1115 reactor 1120 Inverter 1150 Converter for power supply device, 1160 Converter for auxiliary power supply 1200 vehicles 1210 Main battery, 1220 Motor, 1230 Sub battery 1240 Auxiliary equipment, 1250 Wheels 1300 Engine

Claims

1. A reactor including a coil and a magnetic core, The coil has a winding portion, The number of the windings is one, an outer circumferential surface of the winding portion includes a portion that contacts an object on which the reactor is to be installed, The magnetic core is An E-shaped first core portion and a T-shaped second core portion combined in an axial direction of the winding portion; a gap portion provided between the first core portion and the second core portion, the first core portion is composed of a first end core portion facing a first end face of the winding portion, a first middle core portion having a portion disposed inside the winding portion, and a first side core portion and a second side core portion disposed on the outer periphery of the winding portion so as to sandwich the first middle core portion, the first core portion being formed as an integral molded body of a composite material; the second core portion is composed of a powder compact formed integrally with a second end core portion facing a second end surface of the winding portion and a second middle core portion having a portion disposed inside the winding portion, a length of the winding portion in the second middle core portion along the axial direction is shorter than a length of the winding portion in the first middle core portion along the axial direction; the gap portion is disposed inside the winding portion, between the first middle core portion and the second middle core portion, a length from the second end surface to the gap portion is 0.2 times or more and 0.49 times or less the length of the winding portion, The total volume Va of the first core portion, the second core portion, and the gap portion is 50 cm ３ More than 500cm ３ Below is the Reactor.

2. The reactor according to claim 1 , wherein a ratio of a volume of the second core portion to the total volume Va is equal to or greater than 25% and equal to or less than 40%.

3. 3. The reactor according to claim 1, wherein a ratio of a volume of the second middle core portion to a total volume of the first middle core portion, the second middle core portion, and the gap portion is 15% or more and 49% or less.

4. 4. The reactor according to claim 1, wherein a ratio of a thickness of the gap portion to a total length of a length of the first middle core portion, a length of the second middle core portion, and a thickness of the gap portion is 0.001 or more and 0.1 or less.

5. The reactor according to claim 1 , wherein a thickness of the gap portion is equal to or greater than 0.1 mm and equal to or less than 2 mm.

6. The reactor according to claim 1 , further comprising a molded resin portion covering at least a portion of the magnetic core and constituting the gap portion.

7. The reactor according to any one of claims 1 to 6, which constitutes a converter of an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

8. The powder compact is a compact of a raw material powder containing a soft magnetic powder, The reactor according to claim 1 , wherein a content of the soft magnetic powder in the powder compact is 85 vol % or more and 99 vol % or less.

9. The composite material compact is a compact in which soft magnetic powder is dispersed in a resin, The reactor according to claim 1 , wherein a content of the soft magnetic powder in the compact of the composite material is 20% by volume or more and 80% by volume or less.

10. A reactor comprising the reactor according to any one of claims 1 to 9. converter.

11. A converter comprising: Power conversion equipment.

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