Molded coil, reactor, converter, power conversion device, and method for manufacturing molded coil
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AUTONETWORKS TECH LTD
- Filing Date
- 2025-12-08
- Publication Date
- 2026-06-25
Smart Images
Figure JP2025042818_25062026_PF_FP_ABST
Abstract
Description
Molded coil, reactor, converter, power converter, and method for manufacturing molded coil
[0001] This disclosure relates to molded coils, reactors, converters, power converters, and methods for manufacturing molded coils. This application claims priority under Japanese Patent Application No. 2024-221192, dated 17 December 2024. All provisions of the said Japanese application are incorporated herein by reference.
[0002] The reactor described in Patent Document 1 comprises a molded coil and a magnetic core arranged to form a closed magnetic path inside and outside the molded coil. The molded coil comprises a coil and a molded resin portion covering the surface of the coil. The coil is an edgewise coil. The end face shape of the coil is rectangular. The coil comprises a straight portion and a curved portion.
[0003] Japanese Patent Publication No. 2018-195786
[0004] The mold coil of the present disclosure includes a coil having a winding portion formed by a helically wound winding wire, and a mold resin portion that covers a part of the surface of the winding portion and holds the shape of the winding portion. In the mold coil, the winding portion, when viewed from a first direction along the axis of the winding portion, has a virtual outer shape formed by the smallest rectangle that envelopes the winding portion. The outer peripheral surface of the winding portion has a first outer surface and a second outer surface that face each other in a direction along the long side of the rectangle and also in a direction along the short side of the rectangle, and a third outer surface and a fourth outer surface that intersect in a direction along the long side of the rectangle and face each other in a direction along the long side of the rectangle. The first outer surface and the second outer surface are exposed from the mold resin portion. The mold resin portion has at least one of an outer resin portion and an inner resin portion. The outer resin portion covers at least a part of the region in the circumferential direction around the axis of the winding portion and the entire region in the first direction, of the third outer surface and the fourth outer surface. The inner resin portion covers at least a part of the region in the circumferential direction around the axis of the winding portion and the entire region in the first direction, of the inner peripheral surface of the winding portion. In the coil obtained by removing the mold resin portion from the mold coil, the ratio θ / n between the angle θ between the first outer surface of the first turn of the winding portion and the first outer surface of the last turn of the winding portion, when viewed from the first direction, and the number of turns n of the winding portion is 0.2 or more.
[0005] Figure 1 is a schematic perspective view showing a molded coil of Embodiment 1. Figure 2 is a cross-sectional view taken along line II-II of Figure 1. Figure 3 is a cross-sectional view taken along line III-III of Figure 1. Figure 4 is a cross-sectional view taken along line IV-IV of Figure 1. Figure 5 is a front view of the coil with the molded resin portion of Embodiment 1 removed. Figure 6 is a schematic partial cross-sectional view illustrating the manufacturing method of the molded coil of Embodiment 1. Figure 7 is a schematic perspective view showing a molded coil of Embodiment 2. Figure 8 is a cross-sectional view taken along line VIII-VIII of Figure 7. Figure 9 is a cross-sectional view taken along line IX-IX of Figure 7. Figure 10 is a cross-sectional view taken along line X-X of Figure 7. Figure 11 is a first cross-sectional view of the molded coil of Embodiment 3. Figure 12 is a second cross-sectional view of the molded coil of Embodiment 3. Figure 13 is a third cross-sectional view of the molded coil of Embodiment 3. Figure 14 is a first cross-sectional view of the molded coil of Embodiment 4. Figure 15 is a second cross-sectional view of the molded coil of Embodiment 4. Figure 16 is a third cross-sectional view of the molded coil of Embodiment 4. Figure 17 is a schematic perspective view showing the molded coil of Embodiment 5. Figure 18 is a cross-sectional view taken along line XVIII-XVIII in Figure 17. Figure 19 is a schematic perspective view showing the reactor of Embodiment 6. Figure 20 is a schematic configuration diagram showing the power supply system of a hybrid vehicle. Figure 21 is a circuit diagram showing an example of a power conversion device equipped with a converter.
[0006] The above coils are typically manufactured using the following method X. Method X involves repeatedly performing a process of forming a straight section by feeding the winding in a straight line, and then forming a curved section by bending the winding. In method X, the springback is relatively small, making the coil less prone to twisting. Therefore, a molded resin section can be formed on the surface of the coil without correcting the shape of the coil manufactured using method X. However, in method X, the process of feeding the winding, stopping the feeding, bending the winding, and stopping the bending is repeated, resulting in a relatively long manufacturing time for one coil, depending on the size and number of turns of the coil. The longer the manufacturing time for the coil, the longer the manufacturing time for the molded coil, which reduces the productivity of the molded coil and, consequently, the productivity of the reactor.
[0007] One of the objectives of this disclosure is to provide molded coils with excellent productivity.
[0008] The molded coils of this disclosure offer excellent productivity.
[0009] First, the embodiments of this disclosure will be listed and described.
[0010] (1) A molded coil in one embodiment of the present disclosure comprises a coil having a winding portion composed of a spirally wound winding, and a molded resin portion that covers a part of the surface of the winding portion and maintains the shape of the winding portion. In the molded coil, the winding portion, as viewed from a first direction along the axis of the winding portion, has a virtual outer shape composed of the smallest rectangle that encloses the winding portion. The outer circumferential surface of the winding portion has a first outer surface and a second outer surface that are opposite to each other in the direction along the long side of the rectangle and along the short side of the rectangle, and a third outer surface and a fourth outer surface that intersect in the direction along the long side and are opposite to each other in the direction along the long side. The first outer surface and the second outer surface are exposed from the molded resin portion. The molded resin portion has at least one of an outer resin portion and an inner resin portion. The outer resin portion covers at least a portion of the third outer surface and the fourth outer surface in the direction around the axis of the winding portion, and over the entire length in the first direction. The inner resin portion covers at least a portion of the inner circumferential surface of the winding portion in the direction of the axis of the winding portion, and extends over the entire length in the first direction. In the coil obtained by removing the molded resin portion from the molded coil, the ratio θ / n of the angle θ between the first outer surface of the first turn of the winding portion and the first outer surface of the final turn of the winding portion as viewed from the first direction, and the number of turns n of the winding portion, is 0.2 or more.
[0011] In a molded coil with a winding section manufactured by the above-described method X, the above ratio in the coil with the molded resin section removed is less than 0.2. On the other hand, in a molded coil with a winding section manufactured by method Y, the above ratio in the coil with the molded resin section removed is 0.2 or more. This is because method Y has a larger springback than method X, so the coil twists when the molded resin section is removed. Method Y is a method of winding a wire spirally around a shaft member, for example, method Y1 or method Y2 below. Method Y1 is a method in which a winding supply machine rotates around the outer circumference of a non-rotating shaft member, and the winding supplied from the winding supply machine is wound around the outer surface of the shaft member. Method Y2 is a method in which a winding supplied from the winding supply machine is wound around the outer surface of the shaft member by a rotating shaft member. Although it depends on the size of the coil and the number of turns, the manufacturing time for one coil is several tens of seconds for method X, while it is only a few seconds for method Y. Therefore, method Y is superior in coil productivity, and consequently in molded coil productivity. That is, the molded coil described in (1) above, which is equipped with a coil manufactured by method Y, is superior in productivity. Thus, the molded coil described in (1) above can construct a reactor with superior productivity.
[0012] Because the first and second outer surfaces of the molded coil are exposed from the molded resin portion, heat from the coil can be easily transferred to the installation object by bringing either the first or second outer surface into contact with the installation object. In particular, the first and second outer surfaces along the long sides of the virtual outer shape are large surfaces, making it easy to increase the contact area between the coil and the installation object. Therefore, the reactor equipped with the molded coil has excellent heat dissipation properties.
[0013] (2) In the molded coil described in (1) above, the ratio θ / n may be 5 or less.
[0014] The molded coil described in (2) above offers excellent productivity.
[0015] (3) In the molded coil described in (1) or (2) above, the angle θ may be 1° or more.
[0016] The molded coil described in (3) above offers excellent productivity.
[0017] (4) In any of the molded coils described in (1) to (3) above, the angle θ may be 90° or less.
[0018] The molded coil described in (4) above offers excellent productivity.
[0019] (5) In any of the molded coils described in (1) to (4) above, the inner circumferential surface of the winding portion may have a first inner surface and a second inner surface that are opposite to each other in a direction along the long side and along the short side, and a third inner surface and a fourth inner surface that intersect in a direction along the long side and are opposite to each other in a direction along the long side. The molded resin portion has the inner resin portion. The inner resin portion is provided on at least one of the third inner surface and the fourth inner surface.
[0020] The molded coil described in (5) above easily maintains the shape of the coil. Compared to the case where the molded resin part does not have an inner resin part, the molded coil described in (5) above makes it easier to improve the electrical insulation between the middle core part, which is located inside the molded coil, and the coil when constructing the reactor. In addition, the molded coil described in (5) above is easier to make smaller compared to the case where the molded resin part has an outer resin part, if the cross-sectional area perpendicular to the coil axis inside the coil is uniform.
[0021] (6) In any of the molded coils described in (1) to (4) above, the molded resin portion may have the inner resin portion, and the inner resin portion may be provided over the entire inner surface of the winding portion.
[0022] The molded coil described in (6) above easily maintains the shape of the coil. Furthermore, compared to the molded coil described in (5) above, the molded coil described in (6) above makes it easier to improve the electrical insulation between the middle core portion of the magnetic core, which is placed inside the molded coil, and the coil when constructing the reactor.
[0023] (7) In any of the molded coils described in (1) to (6) above, the molded resin portion has the outer resin portion, and the outer resin portion may be provided on at least one of the third outer surface and the fourth outer surface.
[0024] The molded coil described in (7) above easily maintains the shape of the coil. Compared to the case where the molded resin part has an inner resin part, the molded coil described in (7) makes it easier to reduce the distance between the middle core part, which is located inside the molded coil, and the coil when constructing the reactor. Therefore, if the cross-sectional area perpendicular to the coil axis inside the coil is uniform, the molded coil described in (7) above makes it easier to increase the magnetic path area compared to the case where the molded resin part has an inner resin part. If the cross-sectional area perpendicular to the coil axis in the middle core part is uniform, the molded coil described in (7) above is easier to make smaller compared to the case where the molded resin part has an inner resin part.
[0025] (8) One embodiment of the reactor of the present disclosure comprises a molded coil as described in any of (1) to (7) above, and a magnetic core arranged to form a closed magnetic path inside and outside the molded coil.
[0026] The above reactor, equipped with the above-mentioned molded coil, offers excellent productivity and heat dissipation.
[0027] (9) One embodiment of the converter of the present disclosure comprises the reactor of (8) above.
[0028] The above converter, equipped with the above reactor, offers excellent productivity.
[0029] (10) One embodiment of the power conversion device of the present disclosure comprises the converter of (9) above.
[0030] The above power conversion device, equipped with the above converter, offers excellent productivity.
[0031] (11) A method for manufacturing a molded coil according to one embodiment of the present disclosure comprises the steps of: producing a coil having an elliptical cylindrical winding portion by winding a wire spirally around a shaft member; pressing the outer surface of the winding portion from a direction along the minor axis of the winding portion with a core placed inside the winding portion using two opposing molds; and filling and solidifying a resin that covers a part of the surface of the winding portion and maintains the shape of the winding portion while the molds are in contact with the outer surface of the winding portion.
[0032] The above manufacturing method can produce molded coils that have the aforementioned excellent productivity and heat dissipation properties.
[0033] The details of embodiments of this disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same parts. In each drawing, some parts of the configuration may be exaggerated or simplified for ease of explanation. The dimensional ratios of parts in the drawings may also differ from those of the actual components.
[0034] [Embodiment 1] <Molded Coil> The molded coil 2 of Embodiment 1 will be described with reference to Figures 1 to 5. As shown in Figure 1, the molded coil 2 comprises a coil 20 and a molded resin part 25. The coil 20 is composed of a spirally wound wire. The molded resin part 25 covers a part of the surface of the coil 20 and maintains the shape of the coil 20. One of the features of the molded coil 2 of Embodiment 1 is that it comprises a specific coil 20.
[0035] In the following explanation, we will use the following defined first direction D1, second direction D2, and third direction D3. The first direction D1 is the direction along the axis of the coil 20. The second direction D2 is the direction perpendicular to the first direction D1 and is the direction along the long side of the virtual outer shape 21V of the winding portion 21 shown in Figure 2. The third direction D3 is the direction perpendicular to both the first direction D1 and the second direction D2.
[0036] ≪Coil≫ As shown in Figure 1, the coil 20 in this example has two winding sections 21. Each winding section 21 is constructed by winding a wire in a helical shape. The windings constituting each winding section 21 may be independent of each other or may be constructed in a series. That is, the two winding sections 21 may or may not be connected to each other. The windings constituting each winding section 21 may be independent of each other, and each winding may be connected to each other by a member that electrically connects each winding. Unlike this example, the number of winding sections 21 may be one, as in Embodiment 5 which will be described later with reference to Figures 17 and 18. Also, unlike this example, although not shown, the number of winding sections 21 may be three or more.
[0037] Each winding section 21 is a series of windings without joints. The windings are known windings. In this example, the windings are insulated flat wires. The conductor wires of the insulated flat wires are made of copper flat wires. The insulating coating of the insulated flat wires is made of enamel. In this example, the coil 20 is made of insulated flat wire wound edgewise. Unlike this example, the coil 20 may be made of insulated flat wire wound flatwise. Unlike this example, the windings may also be insulated round wires.
[0038] Although not shown in the illustration, both ends of the winding are drawn out from each winding section 21. The insulation coating is stripped from both ends of the winding, exposing the conductor wires. Terminal members (not shown) are connected to the exposed conductor wires. External devices (not shown) are connected to the terminal members. The external devices are, for example, power supplies that supply power to the coil 20.
[0039] As shown in Figure 2, each winding portion 21 viewed from the first direction D1 has a virtual outline 21V composed of the smallest rectangle that encloses the winding portion 21. The virtual outline 21V is the smallest rectangle that circumscribes the cross-section of the winding portion 21. The virtual outline 21V is shown as a dashed line, larger than the contour line of the cross-section of the winding portion 21, in order to distinguish it from the contour line, but in reality it overlaps with the contour line. In this example, the shape of each winding portion 21 is a cylindrical shape with a racetrack shape. The outer circumference shape of the winding portion 21 viewed from the first direction D1 is a racetrack shape. That is, the end face shape of the winding portion 21 viewed from the first direction D1 is a frame shape with a racetrack shape. Because each winding portion 21 is a cylindrical shape with a racetrack shape, it is easier to increase the contact area between each winding portion 21 and the planar installation object compared to the case where each winding portion 21 is a circular cylindrical shape with the same cross-sectional area. Therefore, when the molded coil 2 constructs the reactor 1 (described later with reference to Figure 19), the reactor 1 easily transfers the heat of the coil 20 to the object it is installed on. The object it is installed on is, for example, a cooling base. Furthermore, because the outer circumference shape of each winding section 21 is racetrack-shaped, the height of the coil 20 can be reduced.
[0040] Each winding portion 21 has an outer surface 22 having a first outer surface 221, a second outer surface 222, a third outer surface 223, and a fourth outer surface 224. The first outer surface 221 and the second outer surface 222 are surfaces that are aligned along the long side of the rectangle. The first outer surface 221 and the second outer surface 222 are surfaces that face each other in the direction along the short side of the rectangle. The first outer surface 221 is a surface that faces the third direction D3. The second outer surface 222 is a surface that faces the opposite direction of the third direction D3. The first outer surface 221 and the second outer surface 222 are planes. The third outer surface 223 and the fourth outer surface 224 are surfaces that intersect in the direction along the long side of the rectangle. The third outer surface 223 and the fourth outer surface 224 are surfaces that face each other in the direction along the long side. The third outer surface 223 is a surface that faces the second direction D2. The third outer surface 223 connects the first outer surface 221 and the second outer surface 222. The fourth outer surface 224 is a surface facing the opposite direction of the second direction D2. The fourth outer surface 224 connects the first outer surface 221 and the second outer surface 222. The third outer surface 223 and the fourth outer surface 224 are curved surfaces. The third outer surface 223 of one winding section 21 located on the left side of Figure 2 faces the fourth outer surface 224 of the other winding section 21 located on the right side of Figure 2.
[0041] In this example, the first outer surface 221 and the second outer surface 222 are exposed from the molded resin portion 25. Because the first outer surface 221 and the second outer surface 222 are exposed from the molded resin portion 25, heat from the coil 20 can be easily transferred to the installation object by bringing the first outer surface 221 or the second outer surface 222 into contact with the installation object. In particular, since the first outer surface 221 and the second outer surface 222 are flat surfaces and are large surfaces, surface contact can be made between the coil 20 and the installation object, making it easy to increase the contact area between the coil 20 and the installation object. Therefore, when the molded coil 2 constructs the reactor 1, the reactor 1 has excellent heat dissipation properties. The third outer surface 223 and the fourth outer surface 224 are covered by the molded resin portion 25.
[0042] ≪Molded Resin Part≫ The molded resin part 25 in this example has an outer resin part 26 and does not have an inner resin part 27 as shown in Figures 7 to 10. The outer resin part 26 covers at least a portion of the third outer surface 223 and the fourth outer surface 224 in the direction around the axis of the winding part 21, and over the entire length in the first direction D1. The inner resin part 27 covers at least a portion of the inner circumferential surface 23 of the winding part 21 in the direction around the axis of the winding part 21, and over the entire length in the first direction D1.
[0043] The outer resin portion 26 of this example has a first outer portion 261 and a second outer portion 262. The first outer portion 261 of this example covers the entire area of the winding portion 21 in the axial direction on the third outer surface 223, as shown in Figure 2, and the entire length of the first direction D1, as shown in Figure 4. The second outer portion 262 of this example covers the entire area of the winding portion 21 in the axial direction on the fourth outer surface 224, as shown in Figure 2, and the entire length of the first direction D1, as shown in Figure 4. The first outer portion 261 covering the third outer surface 223 of one winding portion 21 shown on the left in Figures 2 and 4, and the second outer portion 262 covering the fourth outer surface 224 of the other winding portion 21 shown on the right, are formed in a continuous manner. A molded coil 2 having a molded resin portion 25 with a first outer portion 261 and a second outer portion 262 has the following advantages when constructing a reactor 1 compared to a case where the molded resin portion 25 has an inner resin portion 27: It is easier to reduce the distance between the middle core portion 31, which is located inside the molded coil 2 of the magnetic core 3, and the coil 20. Therefore, if the cross-sectional area perpendicular to the axis of the coil 20 inside the coil 20 is uniform, it is easier to increase the magnetic path area. If the cross-sectional area perpendicular to the axis of the coil 20 in the middle core portion 31 is uniform, it is easier to make it smaller. The outer surfaces of the first outer portion 261 and the second outer portion 262 are flat. Therefore, the overall shape of the reactor 1 can be made into a rectangular parallelepiped. A rectangular parallelepiped reactor 1 can be stably installed regardless of which surface is in contact with other members, including the object to be installed.
[0044] As shown in FIGS. 3 and 4, the molded resin portion 25 of this example further includes a first end face resin portion 281 that covers at least a part of the first end face of each winding portion 21, and a second end face resin portion 282 that covers at least a part of the second end face of each winding portion 21. The first end face of each winding portion 21 is a face facing in the first direction D1. The second end face of each winding portion 21 is a face facing in the direction opposite to the first direction D1. Each first end face resin portion 281 of this example covers the entire first end face of each winding portion 21. Each second end face resin portion 282 of this example covers the entire second end face of each winding portion 21. Each first end face resin portion 281 connects the first outer portion 261 and the second outer portion 262. Each second end face resin portion 282 connects the first outer portion 261 and the second outer portion 262. As shown in FIG. 4, the first end face resin portions 281 and the second end face resin portions 282 are formed in series between the winding portions 21.
[0045] The molded resin portion 25 is, for example, a thermosetting resin or a thermoplastic resin. The thermosetting resin is, for example, an epoxy resin, a phenolic resin, a silicone resin, or a urethane resin. The thermoplastic resin is, for example, a polyphenylene sulfide (PPS) resin, a polyamide (PA) resin, a liquid crystal polymer (LCP), a polyimide resin, or a fluororesin. The PA resin is, for example, nylon 6, nylon 66, or nylon 9T.
[0046] As shown in Figure 5, in a coil 20 obtained by removing the molded resin portion 25 from the molded coil 2, the ratio θ / n between the angle θ between the first outer surface 221 of the first turn 21a of the winding portion 21 and the first outer surface 221 of the final turn 21b of the winding portion 21, as viewed from the first direction D1, and the number of turns n of the winding portion 21, is 0.2 or more. The molded resin portion 25 can be removed, for example, by a solvent. A coil 20 in which the ratio θ / n after removal of the molded resin portion 25 is 0.2 or more is manufactured by method Y, which will be described in detail later. On the other hand, in a coil manufactured by method X, the ratio θ / n after removal of the molded resin portion 25 is less than 0.2. Method Y has a shorter manufacturing time for the coil 20 compared to method X. Therefore, method Y is superior in the productivity of the coil 20, and consequently in the productivity of the molded coil 2. Thus, the molded coil 2 can construct a reactor 1 with superior productivity. The ratio θ / n after removal of the molded resin portion 25 is smaller than the ratio θ / n before the formation of the molded resin portion 25, i.e., at the end of step α described later. That is, the ratio θ / n after removal of the molded resin portion 25 does not return to the ratio θ / n at the end of step α. This is because the molded resin portion 25 maintains the shape of the winding portion 21 after its formation. However, the ratio θ / n after removal of the molded resin portion 25 is larger than the ratio θ / n after the twist of the winding portion 21 is corrected, i.e., at the end of step β described later, and is also larger than the ratio θ / n at the time the molded resin portion 25 is formed, i.e., at the end of step γ described later. The ratio θ / n after removal of the molded resin portion 25 is, for example, 5 or less. The ratio θ / n after removal of the molded resin portion 25 may be 0.2 or more and 5 or less, or 0.5 or more and 4 or less. The angle θ after removal of the molded resin part 25 is, for example, 1° or more and 90° or less. The angle θ after removal of the molded resin part 25 may be 5° or more and 85° or less, or 10° or more and 80° or less.
[0047] <Method for Manufacturing Molded Coils> The method for manufacturing molded coils according to Embodiment 1 will be described with reference to Figure 6. The manufacturing method in this example comprises the following steps α to γ. The manufacturing method in this example can produce the molded coil 2 described above.
[0048] Step α involves manufacturing the coil 20 having the elliptical cylindrical winding portion 21 by winding the wire around the shaft member 500 in a spiral shape. The cross-sectional shape of the shaft member 500 in this example is a racetrack shape. The shaft member 500 may have a cross-sectional shape other than the racetrack shape as long as it is two rod-shaped members arranged at intervals from each other. The cross-sectional shape other than the racetrack shape is, for example, a circular shape.
[0049] The winding method of the wire around the shaft member 500 is Method Y. Method Y is either of the following Method Y1 or Method Y2. Method Y1 is a method in which the wire supplied from the wire supply machine is wound around the outer peripheral surface of the non-rotating shaft member 500 by the wire supply machine turning. Method Y2 is a method in which the wire supplied from the wire supply machine is wound around the outer peripheral surface of the rotating shaft member 500 by the rotating shaft member 500. Method Y has a shorter manufacturing time for the coil 20 compared to Method X. However, when the winding portion 21 is removed from the shaft member 500, the winding portion 21 twists as shown in FIG. 5 due to springback in the coil 20 manufactured by Method Y compared to the coil manufactured by Method X. The ratio θ / n in the coil 20 manufactured in Step α is 1 or more and 5 or less.
[0050] In step β, as shown in Figure 6, with a core 630 placed inside each winding section 21, the mold 600 applies pressure to the outer circumferential surface 22 of the winding section 21 from a direction along the short axis of the winding section 21. In step β, the twist of the winding section 21 described above can be corrected by the above pressure. Specifically, the ratio θ / n can be made to less than 1, 0.5 or less, and especially close to 0 (zero). The core 630 may be the shaft member 500, or it may be a different member from the shaft member 500. The mold 600 in this example has an upper mold 610 and a lower mold 620. The upper mold 610 applies pressure to the first outer surface 221 of the winding section 21 in the direction of approaching the second outer surface 222, and the lower mold 620 applies pressure to the second outer surface 222 of the winding section 21 in the direction of approaching the first outer surface 221. This pressurization allows the first outer surface 221 and the second outer surface 222 to be made into planes parallel to each other. Gaps are provided between the inner surfaces of the upper mold 610 and the lower mold 620 and the fourth outer surface 224 of the left winding section 21, and between the inner surfaces of the upper mold 610 and the lower mold 620 and the third outer surface 223 of the right winding section 21. Gaps are also provided between the lower surface of the upper mold 610 and the third outer surface 223 and the fourth outer surface 224 of each winding section 21, and between the upper surface of the lower mold 620 and the third outer surface 223 and the fourth outer surface 224 of each winding section 21.
[0051] In step γ, with the mold 600 in contact with the first outer surface 221 and the second outer surface 222 of the outer circumferential surface 22 of the winding portion 21, a resin is filled and solidified to cover a portion of the surface of the winding portion 21 and maintain the shape of the winding portion 21. The resin to be filled is an unsolidified and fluid resin. In this example, the resin is filled into the gap from the nozzle 650 provided on the upper mold 610 while the ratio θ / n of each winding portion 21 is less than 1. As the resin filled into the gap solidifies, the first outer surface 221 and the second outer surface 222 are exposed from the molded resin portion 25, and the first outer portion 261, the second outer portion 262, the first end face resin portion 281, and the second end face resin portion 282 are formed. Due to the solidification of the resin, the shape of each winding portion 21 is maintained while the ratio θ / n is less than 1, 0.5 or less, and especially near 0 (zero). Furthermore, the shape of each winding portion 21 is maintained when the angle θ is less than 1°, or even 0°.
[0052] [Embodiment 2] <Molded Coil> The molded coil 2 of Embodiment 2 will be described with reference to Figures 7 to 10. The molded coil 2 of Embodiment 2 differs from the molded coil 2 of Embodiment 1 in that the molded resin portion 25 does not have an outer resin portion 26 shown in Figures 2 to 6, but has an inner resin portion 27 shown in Figures 7 to 10. The following description will focus on the differences from Embodiment 1, and the description of the same or similar configurations and effects as in Embodiment 1 will be omitted. This point is also the same for Embodiments 3 to 5 which will be described later.
[0053] ≪Coil≫ The inner circumferential surface 23 of each winding section 21 has a first inner surface 231, a second inner surface 232, a third inner surface 233, and a fourth inner surface 234. The first inner surface 231 and the second inner surface 232 are surfaces that face each other in the direction along the long side and the short side of the rectangle. The first inner surface 231 is the surface that faces away from the third direction D3. The second inner surface 232 is the surface that faces the third direction D3. The first inner surface 231 and the second inner surface 232 are planes. The third inner surface 233 and the fourth inner surface 234 are surfaces that intersect in the direction along the long side of the rectangle and face each other in the direction along the long side. The third inner surface 233 is the surface that faces away from the second direction D2. The third inner surface 233 connects the first inner surface 231 and the second inner surface 232. The fourth inner surface 234 is the surface that faces the second direction D2. The fourth inner surface 234 connects the first inner surface 231 and the second inner surface 232. The third inner surface 233 and the fourth inner surface 234 are curved surfaces.
[0054] ≪Molded Resin Part≫ The inner resin part 27 of this example has a first inner part 271 and a second inner part 272. The first inner part 271 covers the entire area around the axis of the winding part 21 on the third inner surface 233, as shown in Figure 8, and the entire length of the first direction D1, as shown in Figures 9 and 10. The second inner part 272 covers the entire area around the axis of the winding part 21 on the fourth inner surface 234, as shown in Figure 8, and the entire length of the first direction D1, as shown in Figure 10. A molded coil 2 in which the molded resin part 25 has a first inner part 271 and a second inner part 272 makes it easier to improve the electrical insulation between the middle core part 31, which is located inside the molded coil 2 of the magnetic core 3, and the coil 20 when constructing the reactor 1, compared to the case in which the molded resin part 25 does not have an inner resin part 27. Furthermore, a molded coil 2 in which the molded resin portion 25 has a first inner portion 271 and a second inner portion 272 is easier to miniaturize compared to a molded coil 2 in which the molded resin portion 25 has an outer resin portion 26, when the cross-sectional area perpendicular to the axis of the coil 20 inside the coil 20 is uniform.
[0055] As shown in Figures 7 and 10, the first end face resin portion 281 in this example covers a part of the first end face of each winding portion 21. Specifically, the first end face resin portion 281 in this example covers only the portion of the first end face of each winding portion 21 that connects to the third inner surface 233 and the fourth inner surface 234. As shown in Figure 10, the second end face resin portion 282 in this example covers a part of the second end face of each winding portion 21. Specifically, the second end face resin portion 282 in this example covers only the portion of the second end face of each winding portion 21 that connects to the third inner surface 233 and the fourth inner surface 234.
[0056] [Embodiment 3] <Molded Coil> The molded coil 2 of Embodiment 3 will be described with reference to Figures 11 to 13. Figures 11 to 13 each show the molded coil 2 cut at substantially the same position as in Figures 2 to 4. The molded coil 2 of Embodiment 3 differs from the molded coils 2 of Embodiments 1 and 2 in that the molded resin portion 25 has both an outer resin portion 26 and an inner resin portion 27.
[0057] The outer resin portion 26 in this example is substantially the same as the outer resin portion 26 described in Embodiment 1. That is, the outer resin portion 26 in this example has a first outer portion 261 and a second outer portion 262 described in Embodiment 1. The inner resin portion 27 in this example is substantially the same as the inner resin portion 27 described in Embodiment 2. That is, the inner resin portion 27 in this example has a first inner portion 271 and a second inner portion 272 described in Embodiment 2. The molded coil 2 can maintain the shape of the coil 20 more firmly than when the molded resin portion 25 has only one of the outer resin portion 26 and the inner resin portion 27. The molded resin portion 25 in this example further has a first end face resin portion 281 and a second end face resin portion 282.
[0058] The first end face resin portion 281 and the second end face resin portion 282 in this example are substantially the same as the first end face resin portion 281 and the second end face resin portion 282 described in Embodiment 1. The first end face resin portion 281 and the second end face resin portion 282 in this example connect the first inner portion 271 covering the third inner surface 233 and the first outer portion 261 covering the third outer surface 223 of one winding portion 21 shown on the left in Figures 11 and 13, and the second inner portion 272 covering the fourth inner surface 234 and the second outer portion 262 covering the fourth outer surface 224 of the other winding portion 21 shown on the right. Furthermore, the first end face resin portion 281 and the second end face resin portion 282 in this example connect the second inner portion 272 that covers the fourth inner surface 234 and the second outer portion 262 that covers the fourth outer surface 224 of one of the winding portions 21 shown on the left in Figures 11 and 13, and connect the first inner portion 271 that covers the third inner surface 233 and the first outer portion 261 that covers the third outer surface 223 of the other winding portion 21 shown on the right.
[0059] [Embodiment 4] <Molded Coil> The molded coil 2 of Embodiment 4 will be described with reference to Figures 14 to 16. Figures 14 to 16 each show the molded coil 2 cut at substantially the same position as in Figures 2 to 4. The molded coil 2 of Embodiment 4 differs from the molded coil 2 of Embodiment 1 in that the molded resin portion 25 has both an outer resin portion 26 and an inner resin portion 27, and the inner resin portion 27 is provided around the entire circumference of the inner circumferential surface 23 of each winding portion 21. The molded coil 2 in which the inner resin portion 27 is provided around the entire circumference of the inner circumferential surface 23 of each winding portion 21 makes it easier to further improve the electrical insulation between the middle core portion 31, which is located inside the molded coil 2 of the magnetic core 3, and the coil 20.
[0060] The outer resin portion 26 in this example is substantially the same as the outer resin portion 26 described in Embodiment 1. That is, the outer resin portion 26 in this example has the first outer portion 261 and the second outer portion 262 described in Embodiment 1. The molded coil 2 can firmly maintain the shape of the coil 20 compared to the case where the molded resin portion 25 has only one of the outer resin portion 26 and the inner resin portion 27.
[0061] The molded resin portion 25 in this example further comprises a first end face resin portion 281 and a second end face resin portion 282. Each first end face resin portion 281 in this example covers the entire area of the first end face of each winding portion 21. Each second end face resin portion 282 in this example covers the entire area of the second end face of each winding portion 21. Each first end face resin portion 281 and each second end face resin portion 282 connects the outer resin portion 26 and the inner resin portion 27. The first end face resin portions 281 and the second end face resin portions 282 are formed in a continuous line between the winding portions 21, as shown in Figure 16.
[0062] [Embodiment 5] <Molded Coil> The molded coil 2 of Embodiment 5 will be described with reference to Figures 17 and 18. The molded coil 2 of this example differs from the molded coil 2 of Embodiment 1 in that it has only one winding section 21.
[0063] ≪Molded Resin Part≫ The molded resin part 25 in this example does not have an inner resin part 27 as shown in Figures 7 to 10, but has an outer resin part 26, a first end face resin part 281, and a second end face resin part 282. The outer resin part 26 in this example is substantially the same as the outer resin part 26 of Embodiment 1. That is, the outer resin part 26 in this example has a first outer part 261 and a second outer part 262. Although not shown, the molded resin part 25 may be substantially the same as the molded resin part 25 of any of Embodiments 2 to 4 as shown in Figures 7 to 16.
[0064] [Embodiment 6] <Reactor> The reactor 1 of Embodiment 6 will be described with reference to Figure 19. The reactor 1 of this example comprises a molded coil 2 of any of Embodiments 1 to 5 and a magnetic core 3 arranged to form a closed magnetic path inside and outside the molded coil 2. The molded coil 2 of this example is the molded coil 2 of Embodiment 1.
[0065] ≪Magnetic Core≫ The magnetic core 3 in this example has an O-shaped planar form. The magnetic core 3 has two middle core portions 31 and two end core portions 32. Each middle core portion 31 is arranged inside each winding portion 21. Each middle core portion 31 has two middle core pieces 311 and a gap portion 3g arranged between the two middle core pieces 311. Each end core portion 32 is arranged facing the first end face and the second end face of the molded coil 2, respectively, so as to connect the middle core pieces 311 of the middle core portion 31. Each core portion 31, 32 and the gap portion 3g are known core portions 31, 32 and gap portion 3g.
[0066] Each core section 31, 32 is composed of a powder compacted body or a composite material molded body. The powder compacted body is a molded body made by compressing soft magnetic powder. The composite material molded body is a molded body in which soft magnetic powder is dispersed in a resin. The middle core section 31 and the end core section 32 may be composed of the same powder compacted body or the same composite material molded body. Alternatively, the middle core section 31 and the end core section 32 may be composed of different molded bodies, i.e., one is a powder compacted body and the other is a composite material molded body. Known powder compacted bodies and composite material molded bodies can be used. The gap section 3g may be made of, for example, a known non-magnetic ceramic or resin, or it may be an air gap.
[0067] [Embodiment 7] <Converter / Power Conversion Device> The reactor 1 of Embodiment 6 can be used for applications that satisfy the following energizing conditions. The maximum DC current is, for example, about 100A to 1000A. The average voltage is, for example, about 100V to 1000V. The operating frequency is, for example, about 5kHz to 100kHz. The reactor 1 of Embodiment 6 can typically be used as a component of a converter mounted on a vehicle 1200 such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle, or as a component of a power conversion device equipped with this converter.
[0068] As shown in Figure 20, the vehicle 1200 includes a main battery 1210, a power converter 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 driving. The motor 1220 is typically a three-phase AC motor. The motor 1220 drives the wheels 1250 when driving and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 is equipped with an engine 1300 in addition to the motor 1220. In Figure 20, an inlet is shown as the charging point of the vehicle 1200, but it can also be equipped with a plug.
[0069] The power conversion device 1100 includes a converter 1110 and an inverter 1120. The converter 1110 is connected to the main battery 1210. The inverter 1120 is connected to the converter 1110. The inverter 1120 performs mutual conversion between DC and AC. In this example, the converter 1110, when the vehicle 1200 is running, boosts the input voltage of the main battery 1210, which is approximately 200V to 300V, to approximately 400V to 700V and supplies power to the inverter 1120. During regeneration, the converter 1110 steps down the input voltage output from the motor 1220 via the inverter 1120 to a DC voltage suitable for the main battery 1210 and charges the main battery 1210. The input voltage is a DC voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC boosted by the converter 1110 into a predetermined AC and supplies power 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.
[0070] As shown in Figure 21, the converter 1110 comprises a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115. The converter 1110 converts the input voltage by repeatedly switching ON / OFF. In this case, the input voltage conversion is step-up or step-down. Power devices such as field-effect transistors and insulated-gate bipolar transistors are used as switching elements 1111. The reactor 1115 utilizes the coil property that tries to hinder changes in the current that is about to flow through the circuit, and has the function of smoothing the change when the current tries to increase or decrease due to the switching operation. The reactor 1115 is provided as the reactor 1 of Embodiment 6. The power conversion device 1100 and converter 1110 equipped with reactor 1 are excellent in productivity and heat dissipation.
[0071] Vehicle 1200 includes a converter 1110, a power supply converter 1150, and an auxiliary power converter 1160. The power supply converter 1150 is connected to the main battery 1210. The auxiliary power converter 1160 is connected to the main battery 1210 and a sub-battery 1230, which is the power source for the auxiliary equipment 1240. The auxiliary power converter 1160 converts the high voltage of the main battery 1210 to low voltage. The converter 1110 typically performs DC-DC conversion, while the power supply converter 1150 and the auxiliary power converter 1160 perform AC-DC conversion. Some power supply converters 1150 also perform DC-DC conversion. The reactors of the power supply converter 1150 and the auxiliary power converter 1160 have substantially the same configuration as reactor 1 of Embodiment 6, and reactors with appropriately modified size and shape can be used. Furthermore, the reactor 1 of Embodiment 6 can also be used in converters that perform input power conversion, such as converters that only boost voltage or converters that only buck voltage.
[0072] The present invention is not limited to these examples, but is intended to include all modifications within the meaning and scope of the claims as shown, and equivalents thereto. It should be understood that at least one configuration or feature described in each embodiment can be combined with other embodiments or modified in various ways.
[0073] 1 Reactor 2 Molded coil 20 Coil 21 Winding section, 21a First turn, 21b Final turn, 21V Virtual outer shape 22 Outer surface 221 First outer surface, 222 Second outer surface, 223 Third outer surface, 224 Fourth outer surface 23 Inner surface 231 First inner surface, 232 Second inner surface, 233 Third inner surface, 234 Fourth inner surface 25 Molded resin part 26 Outer resin part, 261 First outer part, 262 Second outer part 27 Inner resin part, 271 First inner part, 272 Second inner part 281 First end face resin part, 282 Second end face resin part 3 Magnetic core 31 Middle core part, 311 Middle core piece, 3g Gap part 32 End core part 500 Shaft member 600 Mold, 610 Upper mold, 620 Lower mold, 630 Core, 650 Nozzle 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 Vehicle, 1210 Main battery, 1220 Motor 1230 Sub-battery, 1240 Auxiliary equipment 1250 Wheels, 1300 Engine θ Angle
Claims
1. A molded coil comprising: a coil having a winding portion composed of a spirally wound wire; and a molded resin portion covering a part of the surface of the winding portion and maintaining the shape of the winding portion, wherein in the molded coil, the winding portion viewed from a first direction along the axis of the winding portion has a virtual outer shape composed of the smallest rectangle enclosing the winding portion; the outer surface of the winding portion has a first outer surface and a second outer surface facing each other in a direction along the long side of the rectangle and along the short side of the rectangle; and a third outer surface and a fourth outer surface intersecting in a direction along the long side and facing each other in a direction along the long side; the first outer surface and the second outer surface are exposed from the molded resin portion; the molded resin portion has at least one of an outer resin portion and an inner resin portion; the outer resin portion covers at least a portion of the third outer surface and the fourth outer surface in the direction around the axis of the winding portion and over the entire length in the first direction. The inner resin portion covers at least a portion of the inner circumferential surface of the winding portion in the direction of the axis of the winding portion, and over the entire length in the first direction, and in the coil obtained by removing the molded resin portion from the molded coil, the ratio θ / n of the angle θ between the first outer surface of the first turn of the winding portion and the first outer surface of the final turn of the winding portion as viewed from the first direction and the number of turns n of the winding portion is 0.2 or more, molded coil.
2. The molded coil according to claim 1, wherein the ratio θ / n is 5 or less.
3. The molded coil according to claim 2, wherein the angle θ is 1° or more.
4. The molded coil according to claim 3, wherein the angle θ is 90° or less.
5. The molded coil according to claim 4, wherein the inner circumferential surface of the winding portion has a first inner surface and a second inner surface that are opposite to each other in a direction along the long side and along the short side, and a third inner surface and a fourth inner surface that intersect in a direction along the long side and are opposite to each other in a direction along the long side, and the molded resin portion has the inner resin portion, and the inner resin portion is provided on at least one of the third inner surface and the fourth inner surface.
6. The molded coil according to claim 4, wherein the molded resin portion has the inner resin portion, and the inner resin portion is provided over the entire inner circumferential surface of the winding portion.
7. The molded coil according to claim 4, wherein the molded resin portion has the outer resin portion, and the outer resin portion is provided on at least one of the third outer surface and the fourth outer surface.
8. A reactor comprising a molded coil according to any one of claims 1 to 7, and a magnetic core disposed to form a closed magnetic path inside and outside the molded coil.
9. A converter comprising the reactor described in claim 8.
10. A power conversion device comprising the converter described in claim 9.
11. A method for manufacturing a molded coil, comprising the steps of: producing a coil having an elliptical cylindrical winding portion by spirally winding a winding wire around a shaft member; pressing the outer circumferential surface of the winding portion from a direction along the minor axis of the winding portion with two opposing molds while a core is placed inside the winding portion; and filling and solidifying a resin that covers a part of the surface of the winding portion and maintains the shape of the winding portion while the molds are in contact with the outer circumferential surface of the winding portion.