Title of the invention: Winding iron core
Technical field
[0001]
　This disclosure relates to a wound iron core.
Background technology
[0002]
　The winding core is used as a magnetic core of a transformer, a reactor, a noise filter, or the like. In transformers, low iron loss has been one of the important issues from the viewpoint of high efficiency, and low iron loss has been studied from various viewpoints.
[0003]
　For example, in Japanese Patent Application Laid-Open No. 2017-84889, a circumferential band is wound around the outer periphery of an iron core made of a steel plate wound in a coil shape in the winding direction of the steel plate, and is wound around the iron core on the surface side of the circumferential band. A low noise winding transformer in which a stacking direction band having a vibration loss coefficient η> 0.01 is arranged between the wound wire and the iron core is disclosed.
[0004]
　Further, for example, Japanese Patent Application Laid-Open No. 2018-148536 discloses a wound iron core including a substantially rectangular wound core main body in a side view. The main body of the wound steel core is a grain-oriented electrical steel sheet in which the flat surface portion and the corner portion are alternately continuous in the longitudinal direction, and the angle formed by the two adjacent flat surface portions at each corner portion is 90 °. It includes a portion stacked in the thickness direction and has a substantially rectangular laminated structure in a side view. Each corner portion has two or more bent portions having a curved shape in the side view of the grain-oriented electrical steel sheet, and the total bending angle of each bent portion existing in one corner portion. Is 90 °. Further, the radius of curvature r on the inner surface side in the side view of the bent portion exceeds 1 mm and is less than 3 mm. Further, the surface having a 180 ° magnetic wall parallel to the longitudinal direction, which is composed of the inner surface side and the outer surface side of the directional electromagnetic steel plate, has a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more. The reflux magnetic domain has a region that exists continuously and linearly in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction. The region where the reflux magnetic domain exists occupies 25% or more of the surface area of ​​the steel sheet on the inner surface side or the outer surface side.
Outline of the invention
Problems to be solved by the invention
[0005]
　By the way, transformers and the like using a wound core are widely applied to electrical equipment and electronic equipment, but due to heat generated by iron loss, between the wound core and the winding wound around the wound core. The placed insulating paper may be heated and deteriorated. Insulation paper may break due to deterioration, and a transformer with broken insulation may break down. In order to prevent deterioration of the insulating paper, it is necessary to keep the temperature of the wound core as low as possible. In a general transformer, in order to suppress the temperature rise of the winding core, the winding core is housed in insulating oil (insulating oil), and the heat generated in the winding core due to the retention of this insulating oil is dissipated. There is. However, the insulating oil that contributes to heat dissipation and the wound core are in contact with each other only on the surface of the wound core. Therefore, heat is dissipated by the insulating oil only from the surface of the wound core, and if the amount of heat generated by the wound core is large, the heat dissipation effect may be insufficient.
[0006]
　It is an object of the present disclosure to provide a wound iron core capable of maintaining a low iron loss and suppressing a temperature rise.
Means to solve problems
[0007]
　While diligently studying the suppression of temperature rise in the wound core, the present disclosures have stated that it is important to increase the heat dissipation area in the wound core in order to increase the amount of heat dissipated in the wound core. I found out. Then, I came up with the idea of ​​dissipating heat from between the laminated electromagnetic steel sheets. On the other hand, if the spacing between the laminated electromagnetic steel sheets is excessively increased, the iron loss tends to increase. The present disclosures have reached the present disclosure as a result of further studies on a wound core capable of suppressing a temperature rise of the wound core while maintaining a low iron loss.
[0008]
　The summary of one aspect of the present disclosure made based on the above findings is as follows.
　The wound steel core of one aspect of the present disclosure includes a laminated body in which a plurality of electromagnetic steel sheets are laminated in an annular shape in a side view, and the laminated body is a plurality of layers located between a plurality of bent portions and adjacent bent portions. The side portion of at least one of the plurality of the side portions has a heat transfer path facing the electromagnetic steel sheet in at least a part between the laminated electromagnetic steel sheets. The heat transfer path is only in the side portion.
Effect of the invention
[0009]
　According to the present disclosure, it is possible to provide a wound iron core capable of maintaining a low iron loss and suppressing a temperature rise.
A brief description of the drawing
[0010]
FIG. 1 is a side view showing an example of a wound iron core according to the first embodiment of the present disclosure.
FIG. 2 is a diagram showing an example of a wound iron core according to the first embodiment, and is an enlarged view of a portion X in FIG. 1.
FIG. 3 is a diagram showing an example of a wound iron core according to a second embodiment of the present disclosure, and is an enlarged view of a portion corresponding to a portion X in FIG.
[Fig. 4] Fig. 4 is a graph showing the relationship between the space factor of an electromagnetic steel sheet and the core temperature of a winding iron in a test example.
[Fig. 5] Fig. 5 is a graph showing the relationship between the space factor of the electrical steel sheet at the side of the test example and the core temperature of the winding iron.
Embodiment for carrying out the invention
[0011]
　The embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted. Further, the ratio and dimensions of each component in the figure do not represent the actual ratio and dimensions of each component.
[0012]

　First, the wound iron core according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a side view showing an example of a wound iron core according to the present embodiment. FIG. 2 is a diagram showing an example of a wound iron core, and is an enlarged view of a portion X in FIG. 1. In the following, the case where the electrical steel sheet S is viewed from the side surface side is referred to as a side view. The stacking direction of the electromagnetic steel sheet S is appropriately referred to as a "stacking direction". Further, the plate width direction of the electromagnetic steel sheet S is appropriately referred to as "plate width direction". Further, the winding direction of the electrical steel sheet S is appropriately referred to as "winding direction".
[0013]
　As shown in FIG. 1, the wound steel core 1 according to the present embodiment includes a laminated body 2 in which a plurality of electrical steel sheets S are annularly laminated in a side view (in other words, when the wound steel core 1 is viewed from the side surface). ing. In other words, a plurality of electrical steel sheets S formed in an annular shape are laminated in the plate thickness direction to form the laminated body 2. The laminated body 2 has a plurality of bent portions 21 and a plurality of side portions 22 located between the bent portions 21 adjacent to each other. The side surface of the wound steel core referred to here means a surface formed by the side surface of the laminated electromagnetic steel sheet S.
[0014]
　As shown in FIG. 1, the laminated body 2 is formed by laminating electromagnetic steel sheets S and forming an octagonal shape in a side view, and has a plurality of bent portions 21 and a plurality of side portions 22. Specifically, the laminated body 2 has a rectangular shape formed by bending the electromagnetic steel sheet S on the innermost circumference so as to form four corners 21A, and is an electromagnetic steel sheet located on the outer periphery of the electromagnetic steel sheet S on the innermost circumference. S is bent at the corner portion 21A of the innermost magnetic steel sheet S, and is laminated so as to form two corner portions 21B. Here, the bent portion 21 of the laminated body 2 is a region of a substantially triangular shape connecting one corner portion 21A and two corner portions 21B formed by bending the electromagnetic steel plate S at the corner portion 21A. It is a part. The present disclosure is not limited to this configuration. For example, when there are two corners 21A adjacent to each other, the bent portion 21 of the laminated body 2 is a portion of a substantially trapezoidal region in which the two corners 21A and the two corners 21B are connected by a straight line. May be. Further, the side portion 22 of the laminated body 2 is a substantially linear portion located between the adjacent bent portions 21. As described above, the laminated body 2 of the present embodiment has four bent portions 21 and four side portions 22. The laminated body 2 has an octagonal shape having eight square portions 21B on the outer periphery when viewed from the side surface side of the electromagnetic steel sheet S. On the other hand, the laminated body 2 has a rectangular shape having four corners 21A on the inner circumference.
[0015]
　For the laminated body 2, for example, an existing grain-oriented electrical steel sheet or an existing grain-oriented electrical steel sheet can be used, but it is preferable to use a grain-oriented electrical steel sheet. By using the grain-oriented electrical steel sheet for the laminated body 2, it is possible to reduce the hysteresis loss among the iron losses, and it is possible to further reduce the iron loss of the wound steel core 1.
[0016]
　The thickness of the electrical steel sheet S is not particularly limited, and may be, for example, 0.20 mm or more, or 0.40 mm or less. By using the magnetic steel sheet S having a small thickness (thin), it becomes difficult for an eddy current to occur in the plate thickness surface of the electrical steel sheet S, and it becomes possible to further reduce the eddy current loss among the iron losses. As a result, it is possible to reduce the iron loss of the wound iron core 1. The thickness of the electromagnetic steel sheet S is preferably 0.18 mm or more. The thickness of the electrical steel sheet S is preferably 0.35 mm or less, more preferably 0.27 mm or less.
[0017]
　The laminated electromagnetic steel sheets S are insulated from each other. It is preferable that the surface of the electrical steel sheet S is insulated from each other by insulating the surface. Since the layers of the electrical steel sheet S are insulated, eddy currents are less likely to occur in the thick surface of the electrical steel sheets S, and eddy current loss can be reduced. As a result, it becomes possible to further reduce the iron loss of the wound iron core 1. For example, it is preferable that the surface of the electrical steel sheet S is subjected to an insulating treatment using an insulating coating liquid containing colloidal silica and a phosphate.
[0018]
　As shown in FIG. 2, the laminated body 2 includes a spacer 3 at least a part between the laminated electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22. In the side portion 22 in which the spacer 3 is interposed, a gap portion 22A is formed between the electromagnetic steel sheets S in which the spacer 3 is interposed.
[0019]
　In the laminated body 2 shown in FIG. 2, spacers 3 are interposed between the three electromagnetic steel sheets S in one side portion 22 for each fixed number of laminated magnetic steel sheets S. As a result, a gap portion 22A is formed between the electromagnetic steel sheets S in which the spacer 3 is interposed. When the winding iron core 1 is used by being immersed in the insulating oil, the insulating oil can flow through the gap portion 22A. As a result, the gap portion 22A becomes a heat transfer path for heat generated in the electromagnetic steel sheet S. Then, heat is transferred from the electromagnetic steel sheets S on both sides of the gap portion 22A to the insulating oil flowing through the gap portion 22A, and the heat generated in the electromagnetic steel sheet S is dissipated. The gap portion 22A refers to a gap portion created by the spacer 3 interposing between the electromagnetic steel sheets S, and the size of the gap portion 22A refers to a region including the gap portion and the spacer 3. do.
[0020]
　The length of the gap portion 22A in the stacking direction is preferably 1 mm or more and 2 mm or less. When the length of the gap portion 22A in the stacking direction is 1 mm or more, a sufficient flow rate of insulating oil flows through the gap portion 22A to dissipate the heat of the electrical steel sheet S. This makes it possible to further suppress the temperature rise of the wound iron core 1. The length of the gap portion 22A in the stacking direction is more preferably 1.5 mm or more. Further, when the length of the gap portion 22A in the stacking direction is 2 mm or less, an increase in the magnetic flux (leakage flux) leaking from the electromagnetic steel sheet S to the gap portion 22A is suppressed, and it is possible to suppress an increase in iron loss. .. The length of the gap portion 22A in the stacking direction is more preferably 1.9 mm or less. The length of the gap portion 22A in the stacking direction can be adjusted by changing the length of the spacer 3 in the stacking direction. Further, the length in the stacking direction of the gap portion 22A here refers to the maximum length of the gap portion 22A along the stacking direction of the electromagnetic steel sheet S. The length of the gap portion 22A, which is the heat transfer path, in the stacking direction is equal to or larger than the thickness of one electrical steel sheet S. In other words, the heat transfer path is a gap equal to or larger than the thickness of one electrical steel sheet S.
[0021]
　Further, it is preferable that the length of the gap portion 22A in the stacking direction is substantially constant in the plate width direction. It should be noted that the substantially constant value here includes ± 10% of the length of the gap portion 22A in the stacking direction. Since the length of the gap portion 22A in the stacking direction is substantially constant, the retention of insulating oil in the gap portion 22A is suppressed. As a result, the insulating oil can dissipate the heat of the electromagnetic steel sheet S more efficiently, and the temperature rise of the wound steel core 1 is further suppressed. In order to make the length of the gap portion 22A in the stacking direction substantially constant in the plate width direction, the length in the plate width direction of the spacer 3 or the position of the spacer 3 on the laminated surface of the electromagnetic steel sheet S may be changed. The length of the spacer 3 in the plate width direction is preferably the same as the length of the electromagnetic steel sheet S in the plate width direction. In other words, it is preferable that the spacer 3 extends from one end to the other end of the electrical steel sheet S in the plate width direction along the plate width direction.
[0022]
　If the gap portion 22A is provided on at least one side portion 22, the temperature rise of the wound iron core 1 can be suppressed, but it is preferable that the gap portion 22A is provided on a plurality of side portions 22. By providing the gap portion 22A on more side portions 22, the contact area between the electromagnetic steel sheet S constituting the wound steel core 1 and the insulating oil is increased, and the heat of the electromagnetic steel sheet S can be dissipated more efficiently. It will be possible. Further, by providing the gap portions 22A on the plurality of side portions 22, the temperature rise of the wound iron core 1 is uniformly suppressed. Therefore, it is more preferable that the gap portion 22A is provided on all four side portions 22. When there is a difference in length between the four side portions 22 of the laminated body 2, heat transfer can be efficiently improved by providing a heat transfer path in the long side portion. Specifically, as shown in FIG. 1, the laminated body 2 of the present embodiment has a pair of long side portions facing each other and a pair of short side portions facing each other, and a spacer is provided on at least the long side portions. Is intervening.
[0023]
　The space factor of the electrical steel sheet S in the side portion 22 having the gap portion 22A is preferably 86.0% or more and less than 91.0%. When the space factor of the electrical steel sheet S in the side portion 22 having the gap portion 22A is 86.0% or more, it is possible to maintain a low iron loss. The space factor of the electrical steel sheet S in the side portion 22 having the gap portion 22A is more preferably 89.5% or more. Further, when the space factor of the electromagnetic steel sheet S in the side portion 22 having the gap portion 22A is less than 91.0%, it is possible to further suppress the temperature rise of the wound steel core 1. The space factor in the side portion 22 of the laminated body 2 can be calculated based on JIS C 2550-5: 2011. In addition, JIS C 2550-5: 2011 is IEC 60404-13: 1995, "Magnetic materials-Part 13: Methods of measurement of electricity, resistivity and steering support".
[0024]
　Further, in the gap portion 22A, the distance between the inner peripheral surface of the side portion 22 and the gap portion 22A, the distance between the outer peripheral surface of the side portion 22 and the gap portion 22A, and the distance between the adjacent gap portions 22A are equal in the stacking direction. It is preferable to provide it so as to be. As a result, the winding core 1 is cooled more uniformly by the insulating oil, and the temperature rise of the winding core 1 is suppressed. When the gap portion 22A is provided between one electromagnetic steel sheet S in the side portion 22, the gap portion 22A is the distance between the inner peripheral surface of the side portion 22 and the gap portion 22A and the outer peripheral surface of the side portion 22 and the gap portion 22A. It is preferable that they are provided at positions where the distances are substantially the same.
[0025]
　The spacer 3 is interposed between the electromagnetic steel sheets S in the side portion 22 to form the gap portion 22A. The material of the spacer 3 is preferably a non-magnetic material. If the spacer 3 is a non-magnetic material, it is possible to prevent the generation of eddy currents in the spacer 3, and as a result, it is possible to suppress an increase in iron loss. Specifically, the material of the spacer 3 is preferably resin, copper, brass or the like. Among these, the material of the spacer 3 is preferably copper. Since copper is a material having high thermal conductivity, by using copper for the spacer 3, it is possible to dissipate the heat of the electromagnetic steel sheet S not only by the gap portion 22A but also by the spacer 3 itself.
[0026]
　Further, it is preferable that the spacer 3 is interposed only in the side portion 22 of the laminated body 2. In other words, the gap portion 22A is preferably provided only on the side portion 22 of the laminated body 2. This is because when the gap portion is provided in the bent portion 21, there is a concern that the iron loss due to the leakage of the magnetic flux from the gap portion is increased rather than the increase in the heat radiation area, so that the heat radiation area is secured larger than that in the bent portion 21. It is preferable to provide the gap portion 22A on the formed side portion 22.
[0027]
　The size of the spacer 3 is not particularly limited as long as the gap portion 22A can be formed. However, as described above, in order to make the length of the gap portion 22A in the stacking direction 1 mm or more and 2 mm or less, the length of the spacer 3 in the stacking direction is preferably 1 mm or more and 2 mm or less. Further, if the gap portion 22A capable of suppressing the temperature rise of the wound steel core 1 is formed, the number of spacers 3 interposed between the one electromagnetic steel sheet S is not particularly limited.
[0028]
　Further, in FIG. 2, the spacer 3 is interposed between the three electromagnetic steel sheets S in one side portion 22, but the number of the space between the electromagnetic steel sheets S in which the spacer 3 is interposed is limited to the embodiment shown in FIG. Instead, it may be determined according to the size of the winding iron core 1. However, since the spacer 3 is located between the one or more and three or less electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22, the temperature rise of the wound iron core 1 is suppressed and the iron is ironed. It is possible to further suppress the increase in loss. Therefore, it is preferable that the spacer 3 is located between one or more and three or less electrical steel sheets S in at least one side portion 22 of the plurality of side portions 22.
[0029]

　Subsequently, the winding iron core according to the second embodiment will be described with reference to FIGS. 1 and 3. FIG. 3 is a diagram showing an example of a wound iron core according to the second embodiment of the present disclosure, and is an enlarged view of a portion corresponding to a portion X in FIG.
[0030]
　As shown in FIG. 1, in the wound steel core 1 according to the present embodiment, a plurality of electrical steel sheets S are laminated in an annular shape in a side view, and a side located between the plurality of bent portions 21 and the bent portions 21 adjacent to each other. A laminated body 2 having a portion 22 and a portion 22 is provided. As shown in FIG. 3, the laminated body 2 includes a heat transfer body 4 at least a part between the laminated electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22. The winding iron core 1 according to the present embodiment is the first embodiment in that the heat transfer body 4 is provided in at least a part between the laminated electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22. It is different from the winding iron core 1 according to the form. Since the basic configuration of the laminated body 2 according to the present embodiment is the same as that of the laminated body 2 according to the first embodiment, the description of the laminated body 2 is omitted here. Hereinafter, the heat transfer body 4 will be described in detail.
[0031]
　As described above, the heat transfer body 4 is provided in at least a part of the laminated electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22. In FIG. 3, the heat transfer body 4 is located between the three electrical steel sheets S at one side portion 22. The heat transfer body 4 is provided in at least a part between the laminated electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22, so that the heat generated in the electromagnetic steel sheet S is transferred to the heat transfer body 4. Is radiated to the outside of the winding iron core 1. Therefore, the heat transfer body 4 is a heat transfer path for heat generated in the electromagnetic steel sheet S.
[0032]
　The material of the heat transfer body 4 preferably has a high thermal conductivity. Since the material of the heat transfer body 4 is a material having high heat conductivity, the heat generated in the electromagnetic steel sheet S can be dissipated more efficiently. This makes it possible to suppress the temperature rise of the wound iron core 1. Further, the material of the heat transfer body 4 is preferably a non-magnetic material and an insulator material. If the material of the heat transfer body 4 is a non-magnetic material and an insulating material, it is possible to prevent the generation of eddy currents in the heat transfer body 4. As a result, it becomes possible to suppress an increase in iron loss. Specifically, the material of the heat transfer body 4 is more preferably a phenol resin (baklite). Since the phenol resin has high thermal conductivity, is a non-magnetic material, and is an insulator, the heat generated in the electromagnetic steel plate S can be efficiently dissipated to suppress the temperature rise of the wound iron core 1. By preventing the generation of eddy currents in the heat transfer body 4, it is possible to suppress the increase in iron loss. More specifically, the heat transfer body 4 is preferably a paper-based phenol resin laminated board, a cloth-based phenol resin laminated board, or a glass cloth-based phenol resin laminated board.
[0033]
　The shape of the heat transfer body 4 is not particularly limited, but it is preferable that the heat transfer body 4 is widely interposed between the electromagnetic steel sheets S of the side portions 22. If the heat transfer body 4 is widely interposed between the electromagnetic steel plates S on the side portions 22, the contact area between the electromagnetic steel plate S and the heat transfer body 4 increases, and the heat of the electromagnetic steel plate S can be dissipated more efficiently. Therefore, it is possible to suppress the temperature rise of the wound iron core 1.
[0034]
　If the heat transfer body 4 is provided on at least one side portion 22, the temperature rise of the wound iron core 1 can be suppressed, but it is preferable that the heat transfer body 4 is provided on a plurality of side portions 22. By providing the heat transfer body 4 on more side portions 22, the contact area between the electromagnetic steel plate S constituting the wound iron core 1 and the insulating oil increases, and the heat of the electromagnetic steel plate S passes through the heat transfer body 4. Efficiently flows into insulating oil. That is, the heat of the electrical steel sheet S can be dissipated more efficiently. Further, by providing the heat transfer body 4 on the plurality of side portions 22, the temperature rise of the wound iron core 1 is uniformly suppressed. Therefore, it is more preferable that the heat transfer body 4 is provided on the four side portions 22.
[0035]
　The space factor of the electrical steel sheet S in the side portion 22 having the heat transfer body 4 is preferably 86.0% or more and less than 91.0%. When the space factor of the electromagnetic steel sheet S in the side portion 22 having the heat transfer body 4 is 86.0% or more, it is possible to maintain a low iron loss. The space factor of the electrical steel sheet S in the side portion 22 having the heat transfer body 4 is more preferably 89.5% or more. Further, when the space factor of the electromagnetic steel sheet S in the side portion 22 having the heat transfer body 4 is less than 91.0%, it is possible to further suppress the temperature rise of the wound iron core 1. The space factor can be calculated based on JIS C 2550-5: 2011, but in the present embodiment, it is calculated without considering the mass of the heat transfer body 4.
[0036]
　Further, the heat transfer body 4 has the distance between the inner peripheral surface of the side portion 22 and the heat transfer body 4, the distance between the outer peripheral surface of the side portion 22 and the heat transfer body 4, and the adjacent heat transfer bodies 4 in the stacking direction. It is preferable to provide them so that the distances between them are equal. As a result, the winding core 1 is cooled more uniformly by the insulating oil via the heat transfer body 4, and the temperature rise of the winding core 1 is suppressed. When the heat transfer body 4 is provided between one electromagnetic steel plate S in the side portion 22, the heat transfer body 4 is the distance between the inner peripheral surface of the side portion 22 and the heat transfer body 4 and the outer peripheral surface of the side portion 22 and the heat transfer body 4. It is preferable that the heat transfer body 4 is provided at a position where the distance is substantially the same.
[0037]
　Further, in FIG. 3, the heat transfer body 4 is interposed between the three electromagnetic steel sheets S in one side portion 22, but the number between the electromagnetic steel sheets S in which the heat transfer body 4 is interposed is shown in FIG. The mode is not limited to this, and the determination may be made according to the size of the wound steel core 1. However, since the heat transfer body 4 is located between one or more and three or less electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22, the temperature rise of the wound iron core 1 is suppressed. , It becomes possible to further suppress the increase in iron loss. Therefore, it is preferable that the heat transfer body 4 is located between one or more and three or less electromagnetic steel sheets S in at least one side portion 22 of the plurality of side portions 22.
[0038]

　Hereinafter, some modified examples of the above-described embodiment of the present disclosure will be described. In addition, each modification described below may be applied alone to the said embodiment of the present disclosure, or may be applied in combination to the said embodiment of the present disclosure. Further, each modification may be applied in place of the configuration described in the above embodiment of the present disclosure, or may be additionally applied to the configuration described in the above embodiment of the present disclosure.
[0039]
　Further, in each of the above embodiments, the case where the outer circumference of the laminated body is octagonal has been described, but the present disclosure is not limited to this. The outer circumference of the laminated body may be polygonal, rounded square, oval, oval, or the like. For example, an oval laminate is manufactured by winding an electromagnetic steel sheet. On the other hand, the octagonal laminated body is manufactured by laminating a plurality of electrical steel sheets bent in an annular shape in the plate thickness direction. A laminated body manufactured by laminating a plurality of electrical steel sheets bent in an annular shape in the plate thickness direction tends to have a smaller space factor at the bent portion than a laminated body manufactured by winding an electromagnetic steel sheet. Therefore, the space factor of at least one of the plurality of bent portions 21 of the laminated body 2 may be increased. Specifically, by compressing the bent portion 21 from the inner peripheral side and the outer peripheral side by using a compression means, the gap between the electromagnetic steel sheets S in the bent portion 21 can be reduced. As a result, the space factor of the bent portion 21 becomes high, and the noise of the laminated body 2 can be reduced.
[0040]
　In the above-described embodiment, the case where the inner circumference of the laminated body is a quadrangle has been described, but the present disclosure is not limited to this, and the inner circumference of the laminated body is polygonal, rounded square, oval, or elliptical. And so on. For example, when the inner circumference of the laminated body is octagonal, the portion connecting two adjacent vertices of the octagon is the corner portion, and when the inner circumference of the laminated body is oval, the arc-shaped portion is the corner portion. When the inner circumference of the laminated body is polygonal, rounded square, oval, oval, etc., the bent portion is located between one adjacent side portion and the other side portion, and is one side. This is a portion in which the electromagnetic steel sheet S is bent and laminated with respect to the extending direction of the electromagnetic steel sheet S in the portion and the electromagnetic steel sheet S in the other side portions.
[0041]
　Further, the inner circumference of the laminated body may have a shape corresponding to the shape of the outer circumference. For example, when the outer circumference of the laminate is octagonal, the inner circumference may be octagonal, and when the outer circumference of the laminate is rounded square, the inner circumference may be rounded square.
[0042]
　Needless to say, the heat transfer paths (gap portion 22A, heat transfer body 4) shown in FIGS. 2 and 3 are merely examples, and are not limited to the above-mentioned embodiment. For example, of the overlapping electromagnetic steel sheets S, a concave portion may be formed by bending in a portion constituting the side portion 22 of one of the electromagnetic steel sheets S, and the inside of the concave portion may be used as a gap portion.
[0043]
　The plurality of embodiments according to the present disclosure have been described above. The wound steel core according to these embodiments includes a laminated body in which a plurality of electrical steel sheets are laminated in an annular shape in a side view, and has a plurality of bent portions and side portions located between adjacent bent portions. At least one side portion of the side portion has a heat transfer path facing the electromagnetic steel sheet in at least a part between the laminated electromagnetic steel sheets. By this heat transfer path, the heat generated in the electromagnetic steel sheet when an AC magnetic field is applied is efficiently dissipated, and the temperature rise of the wound iron core is suppressed. Further, since this heat transfer path is provided at least a part between the laminated electromagnetic steel sheets at the side portion, the leakage flux from the electromagnetic steel sheet to the heat transfer path is small, and low iron loss is maintained.
[0044]
　The wound iron core according to this embodiment can be applied to a transformer (not shown). The transformer according to the present embodiment includes a winding core, a primary winding, and a secondary winding according to the present embodiment. When an AC voltage is applied to the primary winding, a magnetic flux is generated in the winding core, and a voltage is generated in the secondary winding due to the change in the generated magnetic flux. Since at least one side of the wound core has a heat transfer path in at least a part between the laminated electromagnetic steel sheets, the heat generated in the wound core is dissipated through this heat transfer path. Will be done. As a result, low iron loss is maintained and temperature rise is suppressed.
[0045]
　Next, the test examples of the present disclosure will be described. The conditions in this test example are one condition example adopted for confirming the feasibility and effect of the present disclosure, and the present disclosure is not limited to this one condition example. The present disclosure may adopt various conditions as long as the gist of the present disclosure is not deviated and the object of the present disclosure is achieved.
[0046]
(Test Example 1)
　A grain-oriented electrical steel sheet having a thickness of 0.23 mm was laminated to prepare a substantially octagonal laminated body having four bent portions and four side portions. The length of the laminated body in the laminating direction was 20 mm, and a wound iron core having each of the four side portions having the number of gaps shown in Table 1 was manufactured under the following conditions. For each of the four sides of the laminated body, a spacer made of phenol resin (Bakelite) was interposed between the electromagnetic steel sheets to provide a gap portion. The gap portion is provided so that the distance between the inner peripheral surface of the side portion and the gap portion, the distance between the outer peripheral surface of the side portion and the gap portion, and the distance between the adjacent gap portions are equal in the stacking direction. Transformer No. In 2, the gap portion is provided at a position where the distance between the inner peripheral surface of the side portion and the gap portion and the distance between the outer peripheral surface of the side portion and the gap portion are substantially the same. Regarding the gap portion, the length in the stacking direction was 1 mm, the length in the plate width direction was 300 mm, and the length in the winding direction was 100 mm. A winding was wound around the wound core, the wound core was installed in the tank, and the inside of the tank was filled with insulating oil to manufacture a transformer having a capacity of 20 kVA.
[0047]
　For the wound iron core, the space factor of the electromagnetic steel sheet at the side was calculated based on JIS C 2550-5: 2011. In addition, iron loss (no load loss) was measured for the manufactured transformer based on JEC-2200. The temperature of the winding core after operating the manufactured transformer for 12 hours was measured. Table 1 shows the number of gaps per side, space factor, temperature, iron loss, and iron loss increase rate. Further, FIG. 4 shows the relationship between the space factor of the magnetic steel sheet at the side portion and the core temperature of the winding iron. The space factor in Table 1 is the average value of the space factor of the electromagnetic steel sheet at the four sides.
[0048]
　The manufactured transformers were evaluated according to the following criteria. Transformer No. without a gap The transformer temperature has dropped with reference to the temperature of No. 1, and the transformer No. When the iron loss increase rate based on the iron loss of 1 is less than 10%, the evaluation result is set to "A (excellent)" and the transformer No. When the transformer temperature has not decreased with respect to the temperature of No. 1, or the transformer No. When the iron loss increase rate based on the iron loss of 1 is 10% or more, the evaluation result is "B (good)". As for the evaluation result, A is better than B. The examples of the invention in Table 1 refer to the examples to which the present disclosure is applied, and the comparative examples refer to the examples to which the present disclosure is not applied.
[0049]
[table 1]

[0050]
　As the number of gaps provided in the side portions increased, the contact area between the wound core and the insulating oil increased, and the temperature of the wound core decreased. Further, as shown in FIG. 4, the winding core temperature decreased as the space factor decreased. Transformer No. In No. 4, the temperature rise was remarkably suppressed. Transformer No. In No. 5, although the temperature rise was suppressed, the rate of increase in iron loss exceeded 10%.
[0051]
(Test Example 2)
　Using a grain-oriented electrical steel sheet having a thickness of 0.20 mm, a rolled iron core was produced by the same method as in Test Example 1, and a transformer having a capacity of 1 kVA was manufactured using the produced wound core. The length of the laminated body in the laminating direction was 20 mm, and a wound iron core having each of the four side portions having the number of gaps shown in Table 2 was manufactured under the following conditions. Regarding the gap portion, the length in the stacking direction was 1 mm, the length in the plate width direction was 200 mm, and the length in the winding direction was 70 mm. For the manufactured transformer, the space factor of the electromagnetic steel sheet at the side, the temperature of the wound core, and the iron loss (no load loss) were measured in the same manner as in Test Example 1. Table 2 shows the number of gaps per side, space factor, temperature, iron loss, and iron loss increase rate. Further, FIG. 5 shows the relationship between the space factor of the magnetic steel sheet at the side portion and the core temperature of the wound iron. The space factor in Table 2 is the average value of the space factor of the electromagnetic steel sheet at the four sides. The evaluation of the transformer was performed according to the same criteria as in Test Example 1. The examples of the invention in Table 2 refer to the examples to which the present disclosure is applied, and the comparative examples refer to the examples to which the present disclosure is not applied.
[0052]
[Table 2]

[0053]
　As the number of gaps provided in the side portions increased, the contact area between the wound core and the insulating oil increased, and the temperature of the wound core decreased. Further, as shown in FIG. 4, the winding core temperature decreased as the space factor decreased. Transformer No. In No. 4, the temperature rise was remarkably suppressed. Transformer No. In No. 5, although the temperature rise was suppressed, the rate of increase in iron loss exceeded 10%.
[0054]
(Test Example 3)
　A grain-oriented electrical steel sheet having a thickness of 0.23 mm was laminated to prepare a substantially octagonal laminated body having four bent portions and four side portions. The length of the laminated body in the stacking direction was 20 mm, and a wound iron core having the number of heat transfer bodies shown in Table 3 on one side of the four sides was manufactured under the following conditions. For one side of the laminated body, a spacer made of Bakelite was interposed between the electromagnetic steel sheets to provide a gap portion. The gap portion is provided so that the distance between the inner peripheral surface of the side portion and the gap portion, the distance between the outer peripheral surface of the side portion and the gap portion, and the distance between the adjacent gap portions are equal in the stacking direction. Transformer No. In 2, the gap portion is provided at a position where the distance between the inner peripheral surface of the side portion and the gap portion and the distance between the outer peripheral surface of the side portion and the gap portion are substantially the same. Regarding the gap portion, the length in the stacking direction was 1 mm, the length in the plate width direction was 150 mm, and the length in the winding direction was 100 mm. A winding was wound around the wound core, the wound core was installed in the tank, and the inside of the tank was filled with insulating oil to manufacture a transformer having a capacity of 10 kVA. For the manufactured transformer, the space factor of the electromagnetic steel sheet, the temperature of the wound steel core, and the iron loss (no load loss) were measured in the side portion having the gap portion by the same method as in Test Example 1. Table 3 shows the number of gaps, the space factor, the temperature, the iron loss, and the iron loss increase rate in the side having the gap. The space factor in Table 3 is the space factor of the electromagnetic steel sheet in the side portion having the gap portion. The evaluation of the transformer was performed according to the same criteria as in Test Example 1. The examples of the invention in Table 3 refer to the examples to which the present disclosure is applied, and the comparative examples refer to the examples to which the present disclosure is not applied.
[0055]
[Table 3]

[0056]
　As described above, according to the present disclosure, it is possible to maintain a low iron loss and suppress a temperature rise.
[0057]
　Although the preferred embodiments and examples of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that anyone with ordinary knowledge in the field of the art to which this disclosure belongs can come up with various modifications or modifications within the scope of the technical ideas set forth in the claims. These are, of course, understood to belong to the technical scope of the present disclosure.
[0058]
　Further, the following additional notes will be disclosed with respect to the above embodiments.
[0059]
　(Appendix 1)
　A laminated body in which a plurality of electrical steel sheets are laminated in an annular shape in a side view is provided, and the
　laminated body has a plurality of bent portions and a plurality of side portions located between adjacent bent portions.
　At least one of the plurality of side portions has a heat transfer path facing the electromagnetic steel sheet in at least a part between the laminated electromagnetic steel sheets, and the heat transfer path is provided
　. The route is a winding iron core located only on the side.
[0060]
　(Supplementary note 2)
　The wound steel core according to Supplementary note 1, wherein the space factor of the electrical steel sheet in the side portion having the heat transfer path is 86.0% or more and less than 91.0%.
[0061]
　(Appendix 3)
　The wound iron core according to Appendix 1 or Appendix 2, wherein the length of the heat transfer path in the laminating direction of the electromagnetic steel sheet is 1 mm or more and 2 mm or less.
[0062]
　(Appendix 4)
　The heat transfer path is located between one or more and three or less of the electrical steel sheets in at least one of the plurality of the side portions, and is any one of the appendices 1 to 3. The winding iron core described in.
[0063]
　(Appendix 5)
　A spacer is provided at least a part between the laminated electromagnetic steel sheets in at least one of the plurality of the side portions, and
　the gap portion created between the electromagnetic steel sheets by the spacer is the transmission. The wound steel core according to any one of Supplementary note 1 to Supplementary note 4, which is a heat path.
[0064]
　(Appendix 6)
　The wound iron core according to Appendix 5, wherein the spacer is a non-magnetic material.
[0065]
　(Supplementary note 7)
　The wound iron core according to any one of Supplementary note 1 to Supplementary note 4, wherein the heat transfer path is formed of a non-magnetic and insulating heat transfer body.
[0066]
　(Appendix 8)
　The wound iron core according to Appendix 7, wherein the heat transfer path is formed of a phenol resin.
[0067]
　(Supplementary note 9)
　The wound iron core according to any one of Supplementary note 1 to Supplementary note 8, wherein all the side portions have the heat transfer path.
[0068]
　(Appendix 10)
　The side portion includes a first side portion and a second side portion longer than the first side portion, and the
　heat transfer path is only in the second side portion. The wound iron core according to any one of Appendix 8.
[0069]
　(Supplementary Note 11)
　The winding according to any one of Supplementary note 1 to Supplementary note 10, wherein the shape of the laminated body when viewed from the side surface is an octagon having four said side portions and four said bent portions. Iron core.
[0070]
(Appendix 12)
　A plurality of electrical steel sheets are laminated in an annular shape in a side view, and a laminated body having a plurality of bent portions and a side portion located between the adjacent bent portions is provided, and the
　plurality of the side portions are provided. At least one of the side portions is a wound steel core having a heat transfer flow path facing the electromagnetic steel sheet in at least a part between the laminated electromagnetic steel sheets.
[0071]
(Appendix 13)
　The wound steel core according to Appendix 12, wherein the space factor of the electrical steel sheet in the side portion having the heat transfer flow path is 86.0% or more and less than 91.0%.
[0072]
(Appendix 14)
　The wound iron core according to Appendix 12 or Appendix 13, wherein the length of the heat transfer flow path in the stacking direction of the electrical steel sheets is 1 mm or more and 2 mm or less.
[0073]
(Appendix 15)
　The heat transfer flow path is provided between one or more and three or less of the electrical steel sheets in at least one of the plurality of the side portions, and any one of the appendices 12 to 14. The winding iron core described in the section.
[0074]
(Appendix 16)
　A spacer is provided at least a part between the laminated electromagnetic steel sheets in at least one of the plurality of the side portions, and
　the gap portion created between the electromagnetic steel sheets by the spacer is the transmission. The wound steel core according to any one of Supplementary note 12 to Supplementary note 15, which is a thermal flow path.
[0075]
(Appendix 17)
　The wound iron core according to Appendix 16, wherein the spacer is a non-magnetic material.
[0076]
(Supplementary note 18)
　The wound iron core according to any one of Supplementary note 12 to Supplementary note 15, wherein the heat transfer flow path is formed of a non-magnetic and insulating heat transfer body.
[0077]
(Supplementary note 19)
　The wound iron core according to Supplementary note 18, wherein the heat transfer flow path is formed of a phenol resin.
[0078]
(Supplementary note 20)
　The wound iron core according to any one of Supplementary note 12 to Supplementary note 19, wherein the shape of the laminated body when viewed from the side surface is octagonal.
[0079]
　The disclosure of Japanese Patent Application No. 2019-160544 filed on September 3, 2019 is incorporated herein by reference in its entirety.
　All documents, patent applications, and technical standards described herein are to the same extent as specifically and individually stated that the individual documents, patent applications, and technical standards are incorporated by reference. Incorporated by reference herein.
The scope of the claims
[Claim 1]
　The laminated body includes a laminated body in which a plurality of electromagnetic steel plates are laminated in an annular shape in a side view, and the laminated body has a 　plurality
　of bent portions and a plurality of side portions located between adjacent bent portions.
The side portion of at least one of the side portions of the above has a heat transfer path facing the electromagnetic steel plate in at least a part between the laminated electromagnetic steel plates, and the
　heat transfer path is the heat transfer path. A winding iron core only on the side.
[Claim 2]
　The wound steel core according to claim 1, wherein the space factor of the electrical steel sheet in the side portion having the heat transfer path is 86.0% or more and less than 91.0%.
[Claim 3]
　The wound steel core according to claim 1 or 2, wherein the length of the heat transfer path in the laminating direction of the electromagnetic steel sheet is 1 mm or more and 2 mm or less.
[Claim 4]
　The winding according to any one of claims 1 to 3, wherein the heat transfer path is located between one or more and three or less of the electrical steel sheets in at least one of the plurality of the side portions. Iron core.
[Claim 5]
　A spacer is provided at least a part between the laminated electromagnetic steel sheets in at least one of the plurality of the side portions, and
　the gap portion created between the electromagnetic steel sheets by the spacer is the heat transfer path. , The wound steel core according to any one of claims 1 to 4.
[Claim 6]
　The wound iron core according to claim 5, wherein the spacer is a non-magnetic material.
[Claim 7]
　The wound iron core according to any one of claims 1 to 4, wherein the heat transfer path is formed of a non-magnetic and insulating heat transfer body.
[Claim 8]
　The wound iron core according to claim 7, wherein the heat transfer path is formed of a phenol resin.
[Claim 9]
　The wound iron core according to any one of claims 1 to 8, wherein all the sides have the heat transfer path.
[Claim 10]
　The side portion has a first side portion and a second side portion longer than the first side portion, and the
　heat transfer path is only in the second side portion, whichever of claims 1 to 8. The wound iron core described in item 1.
[Claim 11]
　The wound iron core according to any one of claims 1 to 10, wherein the shape of the laminated body when viewed from the side surface is an octagon having four said side portions and four said bent portions.