Wound core

Abstract

The present invention relates to a wound iron core, comprising a stacked body formed by stacking a plurality of electromagnetic steel sheets in a ring shape in a side view, the stacked body having a plurality of bent portions and a plurality of side portions located between adjacent bent portions, at least one of the plurality of bent portions being a high filling factor bent portion in which the filling factor of the electromagnetic steel sheets in the bent portion is higher than the average filling factor of the electromagnetic steel sheets in the plurality of side portions.

Description

Technical Field

[0001] The invention relates to a wound core. Background Art

[0002] The wound core is used as a magnetic core of a transformer, a reactor, a noise filter, etc. In the transformer, reducing the iron loss has been one of the important issues from the viewpoint of increasing efficiency, and research on reducing the iron loss has been conducted from various viewpoints.

[0003] In addition, transformers using wound cores are widely used in electrical and electronic equipment, but noise is generated due to magnetostriction when a magnetic field is applied to the wound core. Therefore, research on reducing noise by reducing magnetostriction is active.

[0004] For example, Japanese Patent Gazette No. 2017-84889 discloses a low-noise wound transformer, in which a circumferential band is wound along the winding direction of the steel plate on the outer periphery of an iron core composed of steel plates wound in a coil shape, and a stacking direction band with a vibration loss coefficient η>0.01 is arranged on the surface side of the circumferential band between the winding wound on the iron core and the iron core. Summary of the invention

[0005] Problems to be solved by the invention

[0006] Meanwhile, in order to reduce the iron loss of the wound core, a technique of forming the wound core with a plurality of electromagnetic steel sheets is known. However, there is a tendency that noise due to magnetostriction is easily generated due to the use of electromagnetic steel sheets.

[0007] In recent years, there is a further demand for reducing the noise of wound cores by reducing magnetostriction. However, there is still room for improvement in reducing the noise of wound cores.

[0008] An object of the present invention is to provide a wound core that reduces iron loss and suppresses noise.

[0009] Means for solving problems

[0010] The inventors of the present invention focused on the gaps between stacked electromagnetic steel sheets while conducting intensive research on reducing the noise of wound cores. When a magnetic field that changes with time is applied to a transformer using a wound core, the electromagnetic steel sheets vibrate in the stacking direction due to magnetostriction generated in the electromagnetic steel sheets. Due to this vibration, air density waves are generated from the gaps between the electromagnetic steel sheets. This air density wave is recognized as sound. The inventors of the present invention found that the gap between the electromagnetic steel sheets becomes larger in the curved portion of the wound core, and the gap in the curved portion has a greater impact on the noise of the transformer. Furthermore, it was found that the noise can be reduced by reducing the gap in the curved portion, and as a result of further research, the present invention was realized.

[0011] The gist of one embodiment of the present invention achieved based on the above findings is as follows.

[0012] A wound core according to one embodiment of the present invention comprises a stacked body formed by stacking a plurality of electromagnetic steel sheets in a ring shape in a side view, the stacked body having a plurality of bent portions and a plurality of side portions located between adjacent bent portions, at least one of the plurality of bent portions being a high filling factor bent portion in which a filling factor of the electromagnetic steel sheets in the bent portion is higher than an average filling factor of the electromagnetic steel sheets in the plurality of side portions.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide a wound core that reduces iron loss and suppresses noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a side view showing an example of a wound core according to the first embodiment of the present invention.

[0016] Figure 2 is a diagram showing an example of a compression mechanism provided in the wound core of the first embodiment, and is Figure 1 Exploded perspective view of the X part.

[0017] Figure 3 It is a schematic diagram showing the curved portion before and after the compression mechanism is applied.

[0018] Figure 4 It is a side view showing an example of a wound core according to a second embodiment of the present invention.

[0019] Figure 5 This is a graph showing the relationship between the average filling factor of the electromagnetic steel sheet at four bent portions in the test example and the sound pressure.

[0020] Figure 6 This is a graph showing the relationship between the average filling factor of the electromagnetic steel sheet at four bent portions in the test example and the sound pressure. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail with reference to the accompanying drawings. In addition, in this specification and the drawings, the same symbols are marked on the components having substantially the same functional configuration, thereby omitting a general repetitive description. In addition, the proportions and sizes of the components in the drawings do not represent the actual proportions and sizes of the components.

[0022] <First Embodiment>

[0023] First, refer to Figure 1 to Figure 3 The wound core according to the first embodiment will be described. Figure 1It is a side view showing an example of the wound core according to the present embodiment. Figure 2 is a diagram showing an example of a compression mechanism provided in a wound core, and is Figure 1 Exploded perspective view of the X part. Figure 3 Schematic diagram showing the bent portion before and after the compression mechanism is applied. In addition, in the following, the case where the electromagnetic steel sheet S is viewed from the side is referred to as a side view. The stacking direction of the electromagnetic steel sheet S is appropriately referred to as the "stacking direction". In addition, the plate width direction of the electromagnetic steel sheet S is appropriately referred to as the "plate width direction". Furthermore, the winding direction of the electromagnetic steel sheet S is appropriately referred to as the "winding direction".

[0024] like Figure 1 As shown in FIG. 1 , the wound core 1 of the present embodiment includes a laminate 2 in which a plurality of electromagnetic steel sheets S are laminated in a ring shape in a side view (in other words, the wound core 1 is viewed from the side). In other words, a plurality of electromagnetic steel sheets S formed in a ring shape are laminated in the plate thickness direction to form the laminate 2. The laminate 2 has a plurality of bent portions 21 and a plurality of side portions 22 located between the mutually adjacent bent portions 21. In addition, the side surface referred to here refers to a surface formed by the side surfaces of the laminated electromagnetic steel sheets S.

[0025] like Figure 1 As shown, the laminate 2 is formed into an octagon in a side view by laminating electromagnetic steel sheets S, and has a plurality of bent portions 21 and a plurality of side portions 22. Specifically, the laminate 2 is laminated in the following manner: the innermost electromagnetic steel sheet S is bent in a manner to form four corners 21A to form a rectangular shape, and the electromagnetic steel sheets S located on the outer periphery of the innermost electromagnetic steel sheet S are laminated in a manner to form two corners 21B by bending at the corner 21A of the innermost electromagnetic steel sheet S. Here, the bent portion 21 of the laminate 2 is a portion of a roughly triangular region formed by connecting one corner 21A and two corners 21B formed by bending the electromagnetic steel sheet S at the corner 21A with a straight line. In addition, the present invention is not limited to this configuration. For example, in the case where there are two corners 21A adjacent to each other, the bent portion 21 of the laminate 2 may also be a portion of a roughly trapezoidal region formed by connecting the two corners 21A and the two corners 21B with straight lines, respectively. In addition, the side portion 22 of the laminated body 2 is a substantially straight portion located between adjacent curved portions 21. In this way, the laminated body 2 of the present embodiment has four curved portions 21 and four side portions 22. Furthermore, when viewed from the side surface of the electromagnetic steel sheet S, the laminated body 2 is formed into an octagon having eight corners 21B on the outer periphery. On the other hand, the laminated body 2 is formed into a rectangle having four corners 21A on the inner periphery.

[0026] The filling factor of the electromagnetic steel sheet S in each of the four bent portions 21 of the laminate 2 is substantially constant. In addition, the filling factor of the electromagnetic steel sheet S in each of the four side portions 22 of the laminate 2 is substantially constant. In addition, in the present embodiment, the filling factor of the electromagnetic steel sheet S in each of the four bent portions 21 of the laminate 2 is substantially constant, but the filling factor of the electromagnetic steel sheet S in the four bent portions 21 may be different. In this case, the filling factor of the electromagnetic steel sheet S in the bent portion 21 can be adjusted by the compression mechanism 3 described later.

[0027] The filling factor of the curved portion 21 and the side portion 22 of the stacked body 2 can be calculated based on JIS C 2550-5: 2011. JIS C 2550-5: 2011 corresponds to IEC 60404-13: 1995, "Magnetic materials - Part 13: Methods of measurement of density, resistivity and stacking factor of electrical steel sheets and strips".

[0028] The laminate 2 may be made of conventional grain-oriented electromagnetic steel sheets or conventional non-oriented electromagnetic steel sheets, but is preferably made of grain-oriented electromagnetic steel sheets. By using grain-oriented electromagnetic steel sheets in the laminate 2, hysteresis loss in iron loss can be reduced, and iron loss of the wound core 1 can be further reduced.

[0029] The thickness of the electromagnetic steel sheet S is not particularly limited, and can be, for example, 0.20 mm or more, or 0.40 mm or less. By using an electromagnetic steel sheet S with a relatively small (thin) thickness, it is difficult to generate eddy currents in the thickness plane of the electromagnetic steel sheet S, and the eddy current loss in the iron loss can be further reduced. As a result, the iron loss of the wound core 1 can be reduced. The thickness of the electromagnetic steel sheet S is preferably 0.18 mm or more. In addition, the thickness of the electromagnetic steel sheet S is preferably 0.35 mm or less, and more preferably 0.27 mm or less.

[0030] The stacked electromagnetic steel sheets S are insulated from each other. It is preferred that the surfaces of the electromagnetic steel sheets S be insulated from each other by performing an insulation treatment. By insulating the interlayers of the electromagnetic steel sheets S, it is difficult for eddy currents to be generated in the plate thickness plane of the electromagnetic steel sheets S, and eddy current losses can be reduced. As a result, the iron loss of the wound core 1 can be further reduced. For example, it is preferred that the surfaces of the electromagnetic steel sheets S be insulated using an insulating coating liquid containing colloidal silica and phosphate.

[0031] Furthermore, the wound core 1 includes a compression mechanism 3 for compressing at least one of the plurality of bent portions 21 in the stacking direction of the electromagnetic steel sheets S. Specifically, the compression mechanism 3 compresses the bent portion 21 from both sides in the stacking direction of the electromagnetic steel sheets S (in other words, from the inner peripheral side and the outer peripheral side of the bent portion 21 in the stacking direction of the electromagnetic steel sheets S).

[0032] The compression mechanism 3 of the present embodiment includes an outer plate 31 , an inner plate 32 , bolts 33 , and nuts 34 .

[0033] like Figure 2 As shown, an outer plate 31 and an inner plate 32 are respectively arranged on the outer circumferential side and the inner circumferential side of the bent portion 21. In addition, the length of the outer plate 31 and the inner plate 32 along the plate width direction of the electromagnetic steel plate S constituting the laminated body 2 is greater than the plate width of the electromagnetic steel plate S constituting the laminated body 2, and insertion holes 31A and 32A for inserting bolts 33 are provided at both ends in the length direction of the outer plate 31 and the inner plate 32. In addition, the outer circumferential side and the inner circumferential side of the bent portion 21 mentioned here refer to the outer circumferential side and the inner circumferential side of the bent portion 21 of the laminated body 2.

[0034] The inner plate 32 has a convex portion 32B extending along the length direction of the inner plate 32 according to the shape of the corner portion 21A so as to avoid a gap between the inner plate 32 and the laminate 2. The convex portion 32B is preferably made of a soft material capable of absorbing vibration of the electromagnetic steel sheet S. As the material of the convex portion 32B, for example, resin or wood is preferably used.

[0035] The outer plate 31 and the inner plate 32 are arranged so that the insertion holes 31A and 32A provided at both ends thereof protrude from the side surface of the bent portion 21. The bolts 33 are inserted into the insertion holes 31A of the outer plate 31 and the insertion holes 32A of the inner plate 32 corresponding to the insertion holes 31A, and the nuts 34 are screwed into the bolts 33, thereby connecting the outer plate 31 and the inner plate 32. Then, the nuts 34 are tightened to compress the bent portion 21 in the stacking direction by the outer plate 31 and the inner plate 32. In addition, the outer plate 31 is an example of a first abutting portion, the inner plate 32 is an example of a second abutting portion, and the bolts 33 and the nuts 34 are examples of connecting portions.

[0036] Therefore, the compression mechanism 3 includes a first abutting portion abutting against the outer peripheral side of the curved portion 21, a second abutting portion abutting against the inner peripheral side of the curved portion, and a connecting portion connecting the first abutting portion and the second abutting portion, and the first abutting portion and the second abutting portion are subjected to the restraining force of the connecting portion to compress the curved portion 21 in the stacking direction of the electromagnetic steel sheets S. In other words, the plurality of electromagnetic steel sheets S constituting the curved portion 21 are compressed in the stacking direction.

[0037] Through the above, at least one of the plurality of bent portions 21 is compressed by the compression mechanism 3 in the stacking direction of the electromagnetic steel sheets S in the bent portion 21. Figure 3 As schematically shown in (A), the curved portion 21 before the compression mechanism 3 is applied generates gaps between the electromagnetic steel sheets S. Generally, the filling factor of the electromagnetic steel sheets S in the curved portion 21 before the compression mechanism 3 is applied is smaller than the filling factor of the electromagnetic steel sheets S in the side portion 22. Figure 3 As shown in (B), the gap between the electromagnetic steel sheets S is reduced in the bent portion 21 after being compressed by the compression mechanism 3 in the stacking direction of the electromagnetic steel sheets S. In this way, the packing factor of the electromagnetic steel sheets S in the bent portion 21 can be increased by the compression mechanism 3. In the present embodiment, by using the compression mechanism 3, the packing factor of the electromagnetic steel sheets S in the bent portion 21 can be made higher than the average packing factor of the electromagnetic steel sheets S in the plurality of side portions 22. Thus, when an alternating magnetic field is applied to the wound core 1 in which the gap between the electromagnetic steel sheets S in the bent portion 21 is reduced, the noise generated from the gap between the electromagnetic steel sheets S in the bent portion 21 can be reduced.

[0038] The bent portion 21 in which the filling factor of the electromagnetic steel sheets S is higher than the average filling factor of the electromagnetic steel sheets S in the plurality of side portions 22 corresponds to the high filling factor bent portion of the present invention.

[0039] In addition, the compression mechanism 3 compresses the curved portion 21 so that the filling factor of the curved portion 21 after compression is preferably 93% or more, and more preferably 96% or more. When the filling factor of the curved portion 21 after compression is 93% or more, the gap between the electromagnetic steel sheets S becomes smaller, and the noise of the wound core 1 to which the AC magnetic field is applied can be further reduced. Furthermore, when the filling factor of the curved portion 21 after compression is 96% or more, the noise of the wound core 1 can be further reduced. In addition, the upper limit of the filling factor of the curved portion 21 after compression is 100%.

[0040] In addition, the compression mechanism 3 only needs to be provided in at least one curved portion 21, but is preferably provided in more curved portions 21. By providing the compression mechanism 3 in more curved portions 21, the gaps in the curved portions 21 of the stacked body 2 as a whole become smaller, and noise can be reduced. In addition, the compression mechanism 3 is more preferably provided in all curved portions 21. By providing the compression mechanism 3 in all curved portions 21, the gaps in the electromagnetic steel sheets S as a whole of the stacked body 2 become smaller, and the noise of the wound core 1 to which the AC magnetic field is applied can be further reduced.

[0041] In addition, the outer plate 31, the inner plate 32, the bolt 33 or the nut 34 are formed of a non-magnetic body. As the non-magnetic body, for example, wood, resin, copper or brass is preferably used. If the outer plate 31, the inner plate 32, the bolt 33 or the nut 34 is a non-magnetic body, it is possible to prevent the generation of eddy currents in the compression mechanism 3, and as a result, it is possible to prevent the increase of iron loss.

[0042] In addition, the compression mechanism 3 preferably has an insulating gasket not shown in the figure. By having an insulating gasket in the compression mechanism 3, it is possible to prevent the flow of current in the circuit formed by the outer plate 31, the inner plate 32, the bolts 33 and the nuts 34. As a result, it is possible to prevent the generation of a magnetic field due to the current, and thus a stable magnetic field can be formed. As a result, the increase of iron loss can be prevented. In the case where the compression mechanism 3 does not have an insulating gasket, it is preferred that at least one of the outer plate 31, the inner plate 32, the bolts 33 or the nuts 34 is an insulator. By using an insulator in at least one of the outer plate 31, the inner plate 32, the bolts 33 or the nuts 34, current will not flow to the compression mechanism 3, a stable magnetic field can be formed, and thus the increase of iron loss can be prevented. As an insulating material, various well-known insulators such as natural rubber, epoxy resin, polyvinyl chloride or polyurethane insulating materials can be used.

[0043] As described above, according to the present embodiment, at least one of the plurality of curved portions 21 is compressed by the compression mechanism 3 in the stacking direction of the electromagnetic steel sheets S in the curved portion 21, thereby reducing the gap between the electromagnetic steel sheets S in the compressed curved portion 21. As a result, when an AC magnetic field is applied to the wound core 1, noise generated from the gap can be reduced.

[0044] The wound core 1 of the present embodiment can be applied to a transformer, for example. The transformer of the present embodiment includes the wound core 1 of the present embodiment, a primary winding, and a secondary winding. A magnetic flux is generated in the wound core 1 by applying an AC voltage to the primary winding, and a voltage is generated in the secondary winding by a change in the generated magnetic flux. The stacked body 2 of the wound core is such that at least one of the curved portions 21 is compressed by a compression mechanism 3 in the stacking direction of the electromagnetic steel sheets S in the curved portion 21. Therefore, the gap between the electromagnetic steel sheets S in the compressed curved portion 21 becomes smaller. As a result, the noise of the transformer can be suppressed.

[0045] <Second Embodiment>

[0046] Next, refer to Figure 4 A wound core 1A according to a second embodiment will be described. Figure 4 FIG. 1 is a side view showing an example of a wound core according to the present embodiment. Figure 4As shown, the wound core 1A includes a stacked body 2A and a compression mechanism 3A. The stacked body 2A is different from the stacked body 2 of the first embodiment in that it has four straight corners 21A, but the basic structure is the same as the stacked body 2 described in the first embodiment, so the detailed description is omitted here. In addition, for the same structure as the first embodiment, the same reference numerals are marked and the description thereof is omitted.

[0047] In the first embodiment, the first contact portion and the second contact portion of the compression mechanism 3 receive the restraining force generated by the connecting portion to compress the bent portion 21 in the stacking direction of the electromagnetic steel sheets S. However, the compression mechanism is not limited to the above configuration. Figure 4 As shown. Figure 4 As shown, the stack 2A of the wound core 1A has a curved portion 21 at a position opposite to each other across the center axis C of the stack 2A in a side view. The compression mechanism 3A applies force to the curved portion 21 from the corner 21A to compress the curved portion 21. Specifically, the compression mechanism 3A has a plurality of compression components 35 that compress the two curved portions 21 opposite to each other across the center axis C of the stack 2A in a side view from the corner 21A. The compression component 35 is, for example, a roughly rod-shaped component that can be telescopically adjusted, and a component that can arbitrarily adjust the length or a component composed of an elastic body. The compression component 35 is, for example, a component with a loose thread. The compression component 35 is arranged on the inner side of the stack 2A on a straight line connecting the two corners 21A opposite to each other across the center axis C in a side view. And, by extending the compression component 35, the two curved portions 21 opposite to each other across the center axis C are compressed. Specifically, the compression member 35 presses the two bent portions 21 opposed to each other across the two corner portions 21A, which are opposed to each other across the central axis C in a side view, from the inner circumference to the outer circumference. As a result, the two opposed bent portions 21 are compressed in the stacking direction of the electromagnetic steel sheets S. As a result, the gap between the electromagnetic steel sheets S in the two compressed bent portions 21 becomes smaller, so that the noise of the wound core to which the AC magnetic field is applied can be reduced.

[0048] It is preferable that a plurality of compression members 35 are provided in the plate width direction of the electromagnetic steel sheets S constituting the laminated body 2A. That is, a plurality of compression members 35 arranged on a straight line connecting two corner portions 21A opposed to each other across the central axis C in a side view are arranged in the plate width direction of the electromagnetic steel sheets S constituting the laminated body 2A, whereby two bent portions 21 opposed to each other across the central axis C are uniformly compressed in the plate width direction of the electromagnetic steel sheets S constituting the laminated body 2A. As a result, the noise of the wound core to which the AC magnetic field is applied can be further reduced.

[0049] The compression mechanism 3A preferably includes a plurality of compression components 35A and 35B that compress two pairs of curved portions 21 that are opposed to each other across the central axis C in a side view. As a result, the gap between the electromagnetic steel sheets S can be further reduced as the wound core as a whole, and as a result, the noise of the wound core 1A to which the AC magnetic field is applied can be further reduced. Furthermore, the compression mechanism 3A preferably includes a plurality of compression components 35A arranged on a straight line connecting a pair of corner portions 21A that are opposed to each other across the central axis C in a side view, and a plurality of compression components 35B arranged on a straight line connecting another pair of corner portions 21A, and the plurality of compression components 35A and the plurality of compression components 35B are alternately arranged in the plate width direction of the electromagnetic steel sheet S. As a result, the curved portions 21 are uniformly compressed in the height direction, and the filling factor can be improved.

[0050] In addition, the compression mechanism 3A is preferably a non-magnetic body or an insulator. If the compression mechanism 3A is a non-magnetic body, it is possible to prevent the generation of eddy currents in the compression mechanism 3, and as a result, it is possible to prevent the increase of iron loss. In addition, if the compression mechanism 3A is an insulator, no current flows in the compression mechanism 3A, so a stable magnetic field can be formed. As a result, it is possible to prevent the increase of iron loss.

[0051] <Modification>

[0052] Several modified examples of the above-mentioned embodiment of the present invention are described below. In addition, each modified example described below can be applied to the above-mentioned embodiment of the present invention alone, or can be applied to the above-mentioned embodiment of the present invention in combination. In addition, each modified example can be applied instead of the structure described in the above-mentioned embodiment of the present invention, or can be applied in addition to the structure described in the above-mentioned embodiment of the present invention.

[0053] In the laminated body 2, 2A, it is preferable that, when the average filling factor (%) of the electromagnetic steel sheets S in the four sides 22 is B, the average filling factor A of the electromagnetic steel sheets S in the plurality of bent portions 21 is (B-4.0)% or more. If the average filling factor A is (B-4.0)% or more, the noise of the wound core can be reduced.

[0054] The pressure applied to the curved portion 21 is preferably within a range of 0.2 MPa to 4.0 MPa regardless of the type of compression mechanism. If the pressure applied to the curved portion 21 is within the above range, the noise is reduced and the iron loss is not deteriorated. In addition, for example, in the case of the wound core 1 of the first embodiment, the pressure applied to the curved portion 21 can be managed by the tightening torque of the bolts 33 and the nuts 34.

[0055] In the stacked body 2, 2A, it is preferred that, when the average filling factor (%) of the electromagnetic steel sheets S in the four side portions 22 is B, the filling factor C of the electromagnetic steel sheets S in at least one of the plurality of curved portions 21 is greater than or equal to (B+1)% regardless of the mode of the compression mechanism. If the filling factor C is greater than or equal to (B+1)%, the electromagnetic steel sheets S will not be plastically deformed, and the filling factor in the curved portion 21 can be increased. Since the electromagnetic steel sheets S are not plastically deformed, a non-disturbed magnetic field can be generated, and the increase in leakage magnetic flux can be suppressed. As a result, the increase in iron loss can be suppressed. In addition, since the vibration between the layers of the electromagnetic steel sheets S in the curved portion 21 is suppressed, noise can also be suppressed.

[0056] In addition, in each of the above-mentioned embodiments, the case where the outer periphery of the stack is an octagon is described, but the present invention is not limited to this. The outer periphery of the stack may be a polygon, a rounded square, an oblong or an elliptical shape, etc. For example, an oblong stack is manufactured by winding an electromagnetic steel sheet. On the other hand, an octagonal stack is manufactured by stacking a plurality of electromagnetic steel sheets bent into a ring shape in the direction of the plate thickness. Compared with a stack manufactured by winding an electromagnetic steel sheet, the filling factor of the bent portion of a stack manufactured by stacking a plurality of electromagnetic steel sheets bent into a ring shape in the direction of the plate thickness is likely to become smaller. Therefore, when a compression mechanism is applied to a stack, it is easier to obtain a higher noise reduction effect when a compression mechanism is applied to a stack manufactured by stacking a plurality of electromagnetic steel sheets bent into a ring shape in the direction of the plate thickness than when a compression mechanism is applied to a stack manufactured by winding an electromagnetic steel sheet. In addition, the more times the electromagnetic steel sheet is bent, the smaller the filling factor in the bent portion becomes. Therefore, the effect of improving the filling factor of the curved portion by the compression mechanism becomes greater, and therefore, it is preferable to apply the compression mechanism to the octagonal stacked body.

[0057] In the above embodiment, the case where the inner periphery of the stack 2, 2A is a quadrilateral or an octagon is described, but the present invention is not limited to this, and the inner periphery of the stack 2, 2A can be other polygons, rounded squares, oblongs or ellipses. For example, when the inner periphery of the stack 2, 2A is an octagon, the part connecting two adjacent vertices of the octagon becomes the corner, and when the inner periphery of the stack 2, 2A is an oblong, the arc-shaped part becomes the corner. When the inner periphery of the stack 2, 2A is a polygon, a rounded square, an oblong or an ellipse, the curved portion 21 is located between one adjacent side and the other side, and is a portion that is stacked by bending the electromagnetic steel sheet S relative to the extension direction of the electromagnetic steel sheet S in one side and the electromagnetic steel sheet S in the other side. In addition, the shape of the end of the compression mechanism 3A described in the second embodiment can be a shape corresponding to the shape of the corner 21A. Thereby, the curved portion can be uniformly compressed.

[0058] In addition, the inner periphery of the stack 2, 2A may also be a shape corresponding to the shape of the outer periphery. For example, when the outer periphery of the stack 2, 2A is an octagon, the inner periphery may be an octagon, and when the outer periphery of the stack 2, 2A is a rounded square, the inner periphery may be a rounded square.

[0059] Figure 1 The compression mechanism 3 shown and Figure 4 The compression mechanism 3A shown is only an example, and the compression mechanism is not limited to the above-described embodiment as long as it can compress the curved portion 21 .

[0060] Furthermore, the filling factor of at least one of the plurality of sides 22 of the stacked body 2, 2A may be reduced. Specifically, by disposing a spacer or the like between the electromagnetic steel sheets S in one side 22, the gap between the electromagnetic steel sheets S in the side 22 can be increased. Thus, the heat dissipation area of ​​the stacked body 2, 2A can be increased.

[0061] In addition, the wound core shown as a modified example can be applied to a transformer in the same manner as the wound core 1 of the first embodiment. In the transformer using the wound core shown in this modified example, the gap between the electromagnetic steel sheets in the bent portion is reduced, similarly to the transformer using the wound core 1, so that the noise of the transformer can be suppressed.

[0062] Next, the test example of the present invention is described. The conditions in this test example are a condition example adopted to confirm the feasibility and effect of the present invention, and the present invention is not limited to this condition example. The present invention can adopt various conditions as long as it does not deviate from the main purpose of the present invention and achieves the purpose of the present invention.

[0063] (Test Example 1)

[0064] A laminated body having four bent parts was produced by laminating grain-oriented electromagnetic steel sheets with a thickness of 0.20 mm. A wound core was produced by compressing one of the four bent parts with the pressure shown in Table 1 using a wooden compression mechanism. The produced wound core and Figure 1The wound cores illustrated in the examples have the same structure. A transformer with a capacity of 20kVA was manufactured using the manufactured wound cores. For the wound cores used in the manufactured transformers, the filling factor was calculated based on JIS C 2550-5:2011. In addition, for the manufactured transformers, the iron loss (no-load loss) and the sound pressure were measured based on JEC-2200. Table 1 shows the values ​​of compression force, filling factor, sound pressure and iron loss. In addition, the filling factor C in Table 1 represents the filling factor of the electromagnetic steel sheet in the bending portion after being compressed by the compression mechanism, the filling factor A represents the average filling factor of the electromagnetic steel sheet in the four bending portions, and the filling factor B represents the average filling factor of the electromagnetic steel sheet in the four side portions. In addition, the invention examples in Table 1 refer to embodiments to which the present invention is applied, and the comparative examples are examples to which the present invention is not applied.

[0065] [Table 1]

[0066]

[0067] By making the filling factor of one of the plurality of bent portions higher than the average filling factor of the electromagnetic steel sheets in the four side portions, the sound pressure is reduced and the iron loss is reduced.

[0068] (Test Example 2)

[0069] A laminate having four bent portions was produced by laminating directional electromagnetic steel sheets with a thickness of 0.23 mm. A wound core was produced by compressing the four bent portions of the laminate using a wooden compression mechanism at the pressure shown in Table 2. Figure 1 The wound core illustrated in the example has the same structure. A transformer with a capacity of 20kVA was manufactured using the wound core. For the wound core used in the manufactured transformer, the filling factor was calculated based on JIS C 2550-5:2011. In addition, for the wound core used in the manufactured transformer, the iron loss (no-load loss) and the sound pressure were measured in the same manner as in Test Example 1. Table 2 shows the values ​​of compression force, filling factor, sound pressure, and iron loss. In addition, the average filling factor A in Table 2 represents the average filling factor of the electromagnetic steel sheet in the four bending portions, and the average filling factor B represents the average filling factor of the electromagnetic steel sheet in the four side portions. In addition, Figure 5 The relationship between the average filling factor A and the sound pressure is shown in . In addition, the invention examples in Table 2 refer to examples to which the present invention is applied, and the comparative examples refer to examples to which the present invention is not applied.

[0070] [Table 2]

[0071]

[0072] As shown in Table 2, when the average filling factor A, which is the average filling factor of the electromagnetic steel sheets in the four bent portions, is (B-4.0)% or more, the sound pressure decreases and the iron loss decreases. Figure 5 As shown in FIG. 1 , when the average filling factor A is 96.0% or more, the sound pressure further decreases.

[0073] (Test Example 3)

[0074] A wound core was produced by the same method as in Test Example 1 using a 0.20 mm thick grain-oriented electromagnetic steel sheet, and a transformer with a capacity of 1 kVA was produced using the produced wound core. Figure 1 The wound core illustrated in the example has the same structure. The four bent portions of the wound core were compressed respectively with the pressure shown in Table 3 using a wooden compression mechanism. For the wound core used in the manufactured transformer, the filling factor was calculated based on JIS C 2550-5:2011. In addition, for the wound core used in the manufactured transformer, the iron loss (no-load loss) and the sound pressure were measured in the same manner as in Test Example 1. Table 3 shows the values ​​of compression force, filling factor, sound pressure, and iron loss. In addition, the average filling factor A in Table 3 represents the average filling factor of the electromagnetic steel sheet in the four bent portions, and the average filling factor B represents the filling factor of the electromagnetic steel sheet in the four side portions. In addition, Figure 6 The relationship between the average filling factor A and the sound pressure is shown in . In addition, the invention examples in Table 3 refer to examples to which the present invention is applied, and the comparative examples refer to examples to which the present invention is not applied.

[0075] [Table 3]

[0076]

[0077] As shown in Table 3, when the average filling factor A, which is the average filling factor of the electromagnetic steel sheets in the four bent portions, is (B-4.0)% or more, the sound pressure decreases and the iron loss decreases. Figure 6 As shown in FIG. 1 , when the filling factor A is 96.0% or more, the sound pressure further decreases.

[0078] As described above, according to the present invention, it is possible to provide a wound core that reduces iron loss and suppresses noise.

[0079] The preferred embodiments and examples of the present invention are described in detail with reference to the accompanying drawings, but the present invention is not limited to such examples. Anyone with common knowledge in the technical field of the present invention can think of various changes or modifications within the scope of the technical ideas recorded in the scope of the claims, and it should be understood that these also belong to the technical scope of the present invention.

[0080] The following supplementary notes are further disclosed with respect to the above-mentioned embodiment.

[0081] (Note 1)

[0082] A wound iron core includes a stacked body formed by stacking a plurality of electromagnetic steel sheets in a ring shape in side view.

[0083] The stacked body has a plurality of curved portions and a plurality of side portions located between adjacent curved portions.

[0084] At least one of the plurality of bent portions is a high-filling-factor bent portion in which a filling factor of the electromagnetic steel sheets in the bent portion is higher than an average filling factor of the electromagnetic steel sheets in the plurality of side portions.

[0085] (Note 2)

[0086] In the wound core described in Supplementary Note 1, when an average filling factor (%) of the electromagnetic steel sheets in the plurality of side portions is B, an average filling factor A of the electromagnetic steel sheets in the plurality of bent portions is (B-4.0)% or more.

[0087] (Note 3)

[0088] In the wound core described in Supplementary Note 1 or Supplementary Note 2, a compression mechanism is provided for compressing the plurality of electromagnetic steel sheets in the high space factor bent portion in a stacking direction of the electromagnetic steel sheets.

[0089] (Note 4)

[0090] In the wound core described in Supplementary Note 3, the compression mechanism has:

[0091] a first abutting portion disposed on the outer peripheral side of the high filling factor curved portion and abutting against the high filling factor curved portion;

[0092] a second abutment portion disposed on the inner circumference of the high filling factor curved portion and abutting against the high filling factor curved portion; and

[0093] a connecting portion connecting the first contact portion and the second contact portion,

[0094] The first contact portion and the second contact portion receive a restraining force generated by the connecting portion to compress the plurality of electromagnetic steel sheets in the high filling factor bent portion in a stacking direction of the electromagnetic steel sheets.

[0095] (Note 5)

[0096] In the wound core according to Supplementary Note 4, the first contact portion and the second contact portion or the connecting portion are formed of a non-magnetic body.

[0097] (Note 6)

[0098] In the wound core described in Supplementary Note 3, the bent portions are opposed to each other across the center of the stacked body in a side view.

[0099] The above-mentioned opposite curved portions are respectively the above-mentioned high filling factor curved portions,

[0100] The compression mechanism includes a compression member that compresses the high filling factor curved portions that face each other across the center of the stacked body in a side view.

[0101] (Note 7)

[0102] In the wound iron core described in Note 6, the compression member is a rod-shaped member capable of extension and contraction adjustment, and is arranged on the inner side of the stack and on a straight line connecting the corners of the high filling factor bent portions opposing each other in a side view, and compresses the multiple electromagnetic steel sheets in the high filling factor bent portions opposing each other in the stacking direction of the electromagnetic steel sheets in an extended state.

[0103] (Note 8)

[0104] In the wound core according to Supplementary Note 6 or Supplementary Note 7, the compression member is formed of a non-magnetic body.

[0105] (Note 9)

[0106] In the wound core described in any one of Supplementary Notes 1 to 8,

[0107] The high filling factor bent portion is compressed at a pressure of 0.2 MPa to 4.0 MPa.

[0108] (Note 10)

[0109] In the wound iron core described in any one of Appendix 1 to Appendix 9, when the average filling factor (%) of the electromagnetic steel sheets in the plurality of side portions is set to B, the filling factor C of the electromagnetic steel sheets in the high filling factor bent portion is greater than or equal to B% and less than or equal to (B+1)%.

[0110] (Note 11)

[0111] In the wound core according to any one of Supplementary Notes 1 to 10, all of the bent portions are the high space factor bent portions.

[0112] (Note 12)

[0113] In the wound core according to any one of Supplementary Notes 1 to 11, the shape of the stacked body when viewed from the side is an octagon having the four side portions and the four bent portions.

[0114] (Note 13)

[0115] A wound iron core includes a laminated body, the laminated body being formed by laminating a plurality of electromagnetic steel sheets in a ring shape in a side view, and having a plurality of bent portions and side portions located between adjacent bent portions.

[0116] At least one of the plurality of bent portions is a high-filling-factor bent portion in which a filling factor of the electromagnetic steel sheets in the bent portion is equal to or greater than an average filling factor of the electromagnetic steel sheets in the plurality of side portions.

[0117] (Note 14)

[0118] In the wound core described in Supplementary Note 13, when an average filling factor (%) of the electromagnetic steel sheets in the plurality of side portions is B, an average filling factor A of the electromagnetic steel sheets in the plurality of bent portions is (B-4.0)% or more.

[0119] (Note 15)

[0120] In the wound core according to Supplementary Note 13 or 14, the high space factor bent portion includes a compression mechanism that compresses the plurality of electromagnetic steel sheets in the high space factor bent portion in a stacking direction.

[0121] (Note 16)

[0122] In the wound core described in Supplementary Note 15, the compression mechanism has:

[0123] an abutting portion abutting against the high filling factor bent portion at an outer peripheral side and an inner peripheral side of the high filling factor bent portion; and

[0124] a connecting portion connecting the abutting portion arranged on the outer peripheral side and the abutting portion arranged on the inner peripheral side,

[0125] The contact portion receives the biasing force generated by the connecting portion and compresses the bent portion in the lamination direction of the electromagnetic steel sheets.

[0126] (Note 17)

[0127] In the wound core according to Supplementary Note 16, the contact portion or the connecting portion includes a non-magnetic member.

[0128] (Note 18)

[0129] In the wound core according to Supplementary Note 15, the compression mechanism includes a compression member that compresses the high space factor bent portions that face each other across the center of the stacked body in a side view.

[0130] (Note 19)

[0131] In the wound core according to Supplementary Note 18, the compression member is a non-magnetic body.

[0132] (Note 20)

[0133] In the wound core according to any one of Supplementary Notes 13 to 19, the high filling factor bent portion is compressed at a pressure of 0.2 MPa to 4.0 MPa.

[0134] (Note 21)

[0135] In the wound iron core described in any one of Appendix 13 to Appendix 20, when the average filling factor (%) of the electromagnetic steel sheets in the plurality of side portions is set to B, the filling factor C of the electromagnetic steel sheets in the high filling factor bent portion is greater than or equal to B% and less than or equal to (B+1)%.

[0136] (Note 22)

[0137] In the wound core according to any one of Supplementary Notes 13 to 21, the shape of the stacked body when viewed from the side is an octagon.

[0138] In addition, the entirety of the invention of Japanese Patent Application No. 2019-164446 filed on September 10, 2019 is incorporated into this specification by reference.

[0139] All documents, patent applications, and technical specifications described in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical specification were specifically and individually described.

Claims

1. A wound core, wherein: A laminated body comprising a plurality of electromagnetic steel sheets stacked in a ring shape in side view, The stacked body has a plurality of curved portions and a plurality of side portions located between adjacent curved portions. At least one of the plurality of bent portions is a high filling factor bent portion in which a filling factor of the electromagnetic steel sheets in the bent portion is higher than an average filling factor of the electromagnetic steel sheets in the plurality of side portions. When an average filling factor of the electromagnetic steel sheets in the plurality of side portions is defined as B%, an average filling factor A of the electromagnetic steel sheets in the plurality of bent portions is greater than or equal to (B-4.0)%.

2. The wound core according to claim 1, wherein: A compression mechanism is provided for compressing the plurality of electromagnetic steel sheets in the high filling factor bent portion in a stacking direction of the electromagnetic steel sheets.

3. The wound core according to claim 2, wherein: The above compression mechanism has: a first abutting portion disposed on the outer peripheral side of the high filling factor curved portion and abutting against the high filling factor curved portion; a second abutment portion disposed on the inner circumference of the high filling factor curved portion and abutting against the high filling factor curved portion; as well as a connecting portion connecting the first contact portion and the second contact portion, The first contact portion and the second contact portion receive a restraining force generated by the connection portion, and compress the plurality of electromagnetic steel sheets in the high filling factor bent portion in a stacking direction of the electromagnetic steel sheets.

4. The wound core according to claim 3, wherein: The first contact portion and the second contact portion, or the connecting portion is formed of a non-magnetic body.

5. The wound core according to claim 2, wherein: The bent portions are opposed to each other across the center of the stacked body in a side view, The above-mentioned opposite curved portions are respectively the above-mentioned high filling factor curved portions, The compression mechanism includes a compression member that compresses the high filling factor curved portions that face each other across the center of the stacked body in a side view.

6. The wound core according to claim 5, wherein: The compression component is a rod-shaped component that can be extended and retracted, and is arranged on the inner side of the stacked body and on a straight line connecting the respective corners of the high filling factor bent parts that are opposite to each other in a side view. In an extended state, it compresses the multiple electromagnetic steel sheets in the high filling factor bent parts that are opposite to each other in the stacking direction of the electromagnetic steel sheets.

7. The wound core according to claim 6, wherein: The compression member is formed of a non-magnetic body.

8. The wound core according to any one of claims 1 to 7, wherein: The high filling factor bent portion is compressed at a pressure of 0.2 MPa to 4.0 MPa.

9. The wound core according to any one of claims 1 to 7, wherein: All of the above-mentioned bends are the above-mentioned high filling factor bends.

10. The wound core according to any one of claims 1 to 7, wherein: The shape of the laminated body when viewed from the side is an octagon having the four side portions and the four bent portions.

11. A wound core, wherein: A laminated body comprising a plurality of electromagnetic steel sheets stacked in a ring shape in side view, The stacked body has a plurality of curved portions and a plurality of side portions located between adjacent curved portions. At least one of the plurality of bent portions is a high filling factor bent portion in which a filling factor of the electromagnetic steel sheets in the bent portion is higher than an average filling factor of the electromagnetic steel sheets in the plurality of side portions. When an average filling factor of the electromagnetic steel sheets in the plurality of side portions is defined as B%, a filling factor C of the electromagnetic steel sheets in the high filling factor bent portion is greater than or equal to B% and less than or equal to (B+1)%.

12. The wound core according to claim 11, wherein: All of the above-mentioned bends are the above-mentioned high filling factor bends.

13. The wound core according to claim 11 or 12, wherein: The shape of the laminated body when viewed from the side is an octagon having the four side portions and the four bent portions.

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