Fe-based soft magnetic amorphous alloy thin plate, laminated iron core and rotating electric machine using same, and manufacturing method of Fe-based soft magnetic amorphous alloy thin plate

Abstract

To provide a thin plate of Fe-based soft magnetic amorphous alloy capable of easily reducing the loss of a laminated iron core, laminated iron core using the same, a rotary electric machine, and manufacturing method of thin plate of Fe-based soft magnetic amorphous alloy.SOLUTION: The thin plate of Fe-based soft magnetic amorphous alloy for a laminated iron core is a thin plate of Fe-based soft magnetic amorphous alloy that has opposing front and back sides and side surfaces, and the thickness of which is 10 to 50 μm. The side surfaces have a fracture surface that slopes from each of the front and back sides in the thickness direction of the thin plate and have a V-shape that tapers toward the end in the cross-section of the thin plate in the thickness direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a thin plate of an Fe-based soft magnetic amorphous alloy, a laminated core and a rotating electric machine using the same, and a method for manufacturing the thin plate of an Fe-based soft magnetic amorphous alloy. [Background technology]

[0002] Rotating electric machines used as motors for electric vehicles and hybrid electric vehicles are required to operate with high efficiency by reducing losses caused by the high frequency of alternating magnetic flux resulting from high speed rotation in order to ensure output. Although the efficiency of rotating electric machines has been improved by using inverters, applying rare earth magnets, optimizing structural design, etc., to achieve further efficiency, it is necessary to reduce the iron loss of the laminated iron core used in the magnetic poles. Therefore, there is an increasing demand for the application of low-loss magnetic materials such as Fe-based soft magnetic amorphous alloys and Fe-based nanocrystalline soft magnetic alloys containing fine bcc structure Fe crystalline phases and FeSi crystalline phases and amorphous phases, instead of the magnetic steel sheets used in conventional laminated iron cores.

[0003] As an Fe-based soft magnetic amorphous alloy, for example, Fe-Si-B based soft magnetic alloys are known, which are produced by ultra-rapidly cooling a molten metal adjusted to a specified composition and making it amorphous by a method such as single roll liquid quenching. METGLAS (registered trademark) 2605HB1M and 2605SA1 from METGLAS, Inc. and Fe-Si-B-Cr based 2605SA3 are commercially available.

[0004] Also, Fe-based nanocrystalline soft magnetic alloys are obtained by precipitating (nanocrystallizing) Fe crystalline phases and FeSi crystalline phases by heat treatment of amorphous ribbons obtained in the same manner as Fe-based soft magnetic amorphous alloys. For example, FINEMET (registered trademark) FT-3M from Hitachi Metals, Ltd. and VITROPERM (registered trademark) 800 from VACUUMSCHMELZE GmbH & Co. KG., which are Fe-Si-B-Cu-Nb-based, and NANOPERM (registered trademark) from MAGNETEC Gesellschaft fur Magnettechnologie mbH, which are Fe-B-Zr-Cu-based, are known.

[0005] All of these are also called strips, ribbons, films, or foils, and are usually supplied as long ribbons with a thickness of 10 to several tens of μm. Such ribbons of Fe-based soft magnetic amorphous alloys and Fe-based nanocrystalline soft magnetic alloys are thinner than electromagnetic steel sheets, and can reduce eddy current loss. In addition, Fe-based soft magnetic amorphous alloys and Fe-based nanocrystalline soft magnetic alloys have smaller hysteresis loss than electromagnetic steel sheets, and laminated cores using these ribbons have the advantage of excellent soft magnetic properties.

[0006] On the other hand, Fe-based soft magnetic amorphous alloys, including precursors of Fe-based nanocrystalline soft magnetic alloys, are generally ideal elastoplastic materials that do not undergo strain hardening, and have large plastic deformability and toughness, but they are known to be difficult to elongate under uniaxial stress conditions such as tensile tests. Such Fe-based soft magnetic amorphous alloy ribbons are very hard and have the disadvantage of being less workable than crystalline electromagnetic steel sheets, which is a factor in the slow progress of their application to laminated iron cores, which require processing of ribbons into a specified shape. For this reason, in addition to punching using a die consisting of a punch and a die using a press (hereinafter referred to simply as punching and distinguished from other processing techniques), various processing techniques have been considered to obtain a sheet of a specified shape from a ribbon, such as chemical etching, laser processing, and wire electric discharge machining.

[0007] Patent Document 1 describes the punching of amorphous metal foil. By using a servo press to punch the amorphous metal foil at a predetermined punching speed, the generation of burrs due to plastic deformation is suppressed. Patent Document 2 describes the etching of a ribbon of amorphous alloy material. A crystallized region is formed in a predetermined shape in advance in the ribbon, and the crystallized region is etched to increase the etching speed. This improves productivity in the etching process. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 62-9898 [Patent Document 2] Japanese Patent Application Publication No. 55-145174 Summary of the Invention [Problem to be solved by the invention]

[0009] FIG. 5 shows an example of a thin plate used in a laminated core in a perspective view. In the illustrated example, the thin plate 1 is rectangular, has opposing front and back surfaces 20, and four side surfaces 25 connecting the front and back surfaces 20. The thin plate 1 obtained from the thin strip easily bends, but when placed on a surface plate, the front and back surfaces 20 of the thin plate 1 are substantially flat, and if no plastic deformation such as bending occurs, the shape shown in the figure will be obtained. The front and back surfaces 20 of the thin plate 1 remain planar bodies when the thin strip is produced, and the side surfaces 25 are cross-sectional surfaces obtained by processing. FIG. 6 is a perspective view showing an example of a laminated core formed by stacking multiple thin plates. In the laminated core 5, several to several thousand thin plates 1 are stacked, and the thin plates 1 are fixed and integrated with each other by means of spot welding, caulking, adhesive, or the like.

[0010] FIG. 15 shows a simplified part of a press machine for explaining the punching process. FIG. 16 shows an enlarged perspective view of the state of the side of the thin plate produced by the punching process. Typically, the side 25 of the thin plate 1 is formed with a shear surface 135 and a fracture surface 138 due to shear stress caused by punching, as well as a sag 131 and a burr 120 due to plastic deformation in the thickness direction of the thin plate 1. In the punching method, a thin ribbon (not shown) is placed on a die 19 having a punching hole and pressed down, while a punch 18 is lowered from above the punching hole, and the punch 18 is passed through the punching hole of the die 19 at intervals of several μm to 100 μm depending on the thickness of the thin ribbon, and the thin ribbon is sheared between the cutting edge provided on the edge of the tip side of the punch 18 and the cutting edge provided on the edge of the punching hole of the die 19. The thin plate 1 punched out of the thin ribbon by the shearing process is formed with a burr 120 along the outer periphery of the punch 18 in the thickness direction.

[0011] According to the method described in Patent Document 1, the degree of burrs occurring in the thickness direction of a thin plate can be suppressed, but it is inevitable that the height of the burrs will increase due to changes over time such as wear of the die and punch, etc. In the first place, due to the mechanism of punching, it is difficult to eliminate the occurrence of burrs occurring in the thickness direction of a thin plate. In addition, the etching method does not produce burrs in the thickness direction that appear in thin plates when punching, but it requires multiple processes such as resist coating and etching, which makes it less productive than punching and unsuitable for mass production of thin plates. Laser processing and electric discharge processing are also slower than punching, making them less productive.

[0012] FIG. 17 shows an enlarged cross section of a laminated core formed by stacking thin plates having burrs. The thin plates 1 are stacked with a misalignment in the surface direction via a resin layer 200 that bonds the layers. Burrs 120 that occur on the side of the thin plates 1 protrude from the front and back surfaces 20, and may cause the thin plates 1 to come into contact with each other during stacking, resulting in an electrical short circuit. A short circuit between the thin plates 1 increases eddy current loss, which is an obstacle to reducing loss in the laminated core 5. In addition, since the burrs 120 occur on the edges of the thin plates 1, as the number of layers of the thin plates 1 increases, the side sides of the laminated core 5 become thicker and bulkier than the center, which also affects the dimensional accuracy of the laminated core 5. In addition, there are cases where the space factor of the laminated core 5 (the ratio of the volume of the thin plates to the volume of the laminated core) cannot be increased.

[0013] Therefore, the present invention aims to provide a thin plate of an Fe-based soft magnetic amorphous alloy that can easily reduce losses in laminated cores, a laminated core and a rotating electric machine using the same, and a method for manufacturing the thin plate of an Fe-based soft magnetic amorphous alloy. [Means for solving the problem]

[0014] According to one embodiment of the present invention, there is provided a thin plate of an Fe-based soft magnetic amorphous alloy for a laminated core, the thin plate having opposing front and back surfaces and a side surface, a thickness of 10 to 50 μm, and the side surface is inclined from each of the front and back surfaces with respect to the thickness direction of the thin plate. Ductile fractureIt is possible to provide a thin plate of an Fe-based soft magnetic amorphous alloy having a fractured surface and a V-shape tapered toward one end in a cross section in the thickness direction of the plate.

[0015] According to one aspect of the present invention, It is preferred that all sides of the sheet are V-shaped.

[0016] According to one aspect of the present invention, The fracture surface is preferably a region extending from the V-shaped end portion, which is the outer edge of the thin plate, to a distance L of 5 μm or more inward.

[0017] According to another aspect of the present invention, It is possible to provide a laminated core made of thin sheets of an Fe-based soft magnetic amorphous alloy.

[0018] According to another aspect of the present invention, It is possible to provide a rotating electric machine using a laminated core, in which thin plates of an Fe-based soft magnetic amorphous alloy are stacked and fixed, in the stator or rotor.

[0019] According to another aspect of the present invention, The present invention provides a method for producing a thin sheet of an Fe-based soft magnetic amorphous alloy, in which a non-metallic ribbon having a thickness of 10 to 150 μm is superimposed on the front and back surfaces of a thin sheet of an Fe-based soft magnetic amorphous alloy having a thickness of 10 to 50 μm, and the thin sheet of the Fe-based soft magnetic amorphous alloy together with the non-metallic ribbon is cut with a rotary die cutter or a Thomson blade to obtain a thin sheet having opposing front and back surfaces and side surfaces, the side surfaces being inclined from each of the front and back surfaces in the thickness direction of the thin sheet, and having a V-shaped fracture surface tapered toward the end in a cross section in the thickness direction.

[0020] According to another aspect of the present invention, It is preferable that the cutting edge of the rotary die cutter or the Thompson blade is flat. Effect of the Invention

[0021] According to the present invention, it is possible to provide a thin plate of an Fe-based soft magnetic amorphous alloy that can easily reduce losses in a laminated core, a laminated core and a rotating electric machine using the same, and a method for manufacturing the thin plate of an Fe-based soft magnetic amorphous alloy. [Brief description of the drawings]

[0022] [Figure 1] 1 is an enlarged perspective view of a side surface of a thin plate of an Fe-based soft magnetic amorphous alloy according to one embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view of a thin plate of an Fe-based soft magnetic amorphous alloy according to an embodiment of the present invention, cut in the thickness direction. [Diagram 3] 1 is a configuration diagram showing one embodiment of an apparatus for processing a ribbon of an Fe-based soft magnetic amorphous alloy. [Figure 4]4 is a perspective view showing one embodiment of a die-cut roll used in the processing device of FIG. 3. FIG. [Diagram 5] FIG. 2 is a perspective view showing one embodiment of a thin plate used in a laminated core. [Figure 6] 1 is a perspective view showing one embodiment of a laminated core formed by stacking a plurality of thin plates; [Figure 7] 1 is a cross-sectional view showing an embodiment of a cross section of a laminated core formed by stacking a plurality of thin plates. [Figure 8] FIG. 2 is a perspective view showing another embodiment of a thin plate of an Fe-based soft magnetic amorphous alloy. [Figure 9] 9 is a partially enlarged perspective view of the thin plate of the Fe-based soft magnetic amorphous alloy shown in FIG. 8. [Figure 10] 11 is a perspective view showing another embodiment of a laminated core formed by stacking a plurality of thin plates. FIG. [Figure 11] 1 is a schematic diagram showing an embodiment of a rotating electric machine using a laminated core of the present invention; [Figure 12] 1 is a laser microscope photograph of the side surfaces of the front and back surfaces of the thin plate of Example 1. [Figure 13] 1 is a laser microscope photograph of the side surface of a cross section of the thin plate of Example 1. [Figure 14] 1 is a laser microscope photograph of the surface profile of the thin plate of Example 1. [Figure 15] FIG. 2 is a simplified cross-sectional view of a part of a press device for punching a thin strip. [Figure 16] FIG. 2 is an enlarged perspective view of a side of a thin plate produced by punching. [Figure 17] 1 is a cross-sectional view of a laminated core formed by stacking thin plates having burrs. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, the embodiment of the present invention will be described in detail, but the present invention is not limited thereto. In addition, in some or all of the drawings, parts unnecessary for the explanation are omitted, and some parts are illustrated by enlarging or reducing the size in order to facilitate the explanation. In this specification, a numerical range expressed by using "~" means a range including the numerical values ​​written before and after "~" as the lower and upper limits. In this specification, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[0024] FIG. 1 shows an enlarged perspective view of a side of a thin plate of an Fe-based soft magnetic amorphous alloy according to one embodiment of the present invention. The thin plate according to one embodiment of the present invention may have the same form as that shown in FIG. 5. The side 25 of the thin plate 1 is a processed cross section of an inclined surface 30 inclined from each of the front and back surfaces 20 to the thickness direction of the thin plate 1 (z direction in the drawing). FIG. 2 is a cross section of the thin plate 1 cut in the thickness direction. In the cross section (xz plane) of the thin plate 1 in the thickness direction, the side 25 of the thin plate 1 is V-shaped tapered toward the end. The inclined surface 30 has a fracture surface 85 due to ductile fracture in the range of a distance L from the end of the V shape toward the front and back surfaces 20. Here, ductile fracture is a fracture accompanied by plastic deformation, and according to the structural observation of the fracture surface by an electron microscope, fine deformation marks are observed on the fracture surface, and the fracture surface exhibits a mode different from that of brittle fracture or fatigue fracture. Since the inclined surfaces are continuous with the opposing front and back surfaces 20, it is not necessary to stack the front and back surfaces 20 of the thin plate 1 separately to form a laminated core, which makes handling easy.

[0025] Most of the inclined surface 30 is a fracture surface 85. Microscopically, the fracture surface 85 is a discontinuous surface composed of surfaces with different inclinations, but macroscopically, it is sufficient if it is a surface that moves from the flat front and back surfaces 20 toward the edge of the thin plate and away from the front and back surfaces 20. The side surface 25 includes not only a linearly inclined inclined surface as shown in the cross section of the thickness direction of the thin plate 1, but also a curved inclined inclined surface and a wavy (undulating) form. In addition, the inclined surface form and the region of the fracture surface 85 between the distance L from the end of the V-shape may be different between the inclined surface continuing from one front and back surface and the inclined surface continuing from the other front and back surface. In addition, the fracture surface may have a vein structure. The vein structure is a structure characteristic of amorphous alloys, and is known to be observed in fracture surfaces caused by tension. The vein structure is considered to be generated as a result of viscous flow deformation caused by localized temperature rise due to insulation.

[0026] As described above, in the thin plate 1 formed by punching, the angle between the front and back surfaces 20 and the side surface 25 (fracture surface 138) is an acute angle due to the burr 120, protruding toward the front and back surface 20. On the other hand, in the thin plate 1 of the present invention, there is no burr protruding toward the front and back surface 20, and the angle between the front and back surface 20 and the side surface 25 (inclined surface 30) is an obtuse angle. FIG. 7 shows a cross section of a laminated core 5 formed by stacking such thin plates 1. As shown in the figure, the laminated core 5 can be formed in which interference such as contact between the thin plates 1 due to the burr does not occur in the laminated core 5, and an increase in eddy current loss due to short circuit is suppressed. In the side surface 25 of the thin plate 1, the V-shaped portion may be a part, but it is preferable that the V-shaped portion is 50% or more of the circumference of the side surface, and more preferably 80% or more.

[0027] In punching, it is difficult to eliminate the generation of burrs that protrude in the thickness direction at the edge of a thin plate. Therefore, the present inventors have studied various processing techniques for obtaining a thin plate of a predetermined shape from a thin ribbon. In the process, they have found that the generation of burrs protruding in the thickness direction of the thin plate can be prevented by using a Thomson blade or a rotary die cutter to push and cut the thin ribbon. By using a combination of a Thomson blade and a receiving stand described later, or a combination of a die cut roll and anvil roll, the thin ribbon is crushed with the blade edge to plastically deform and break, so that the obtained thin plate does not have burrs protruding in the thickness direction that are generated by shearing, and the side surface 25 is composed of an inclined surface 30 having a fracture surface 85, and has a tapered V-shape as shown in FIG. 1.

[0028] In a laminated core, the sheet thickness of the thin plate is preferably thin in order to reduce eddy current loss. On the other hand, the thinner the sheet thickness, the lower the space factor tends to be due to the influence of surface roughness, unevenness, etc. For this reason, the thickness of the thin plate (thin ribbon) of the Fe-based soft magnetic amorphous alloy is preferably 10 μm or more and 50 μm or less. More preferably, it is 12 μm or more, and even more preferably, it is 15 μm or more. Furthermore, it is more preferably 45 μm or less, and even more preferably, it is 40 μm or less. Furthermore, the aforementioned METGLAS (registered trademark) 2605SA1, etc., which are commercially available, can be appropriately used as the thin ribbon of the Fe-based soft magnetic amorphous alloy.

[0029] Hereinafter, the manufacturing method of the thin plate of the Fe-based soft magnetic amorphous alloy of the present invention will be specifically described with reference to the drawings. FIG. 3 is a configuration diagram of a processing device for a thin strip including a rotary die cutter. The rotary die cutter is composed of a cylindrical die cut roll 350 and an anvil roll 355, and a sheet-shaped workpiece is inserted between the die cut roll 350 and the anvil roll 355 while rotating. The workpiece is a laminate of a thin strip of the Fe-based soft magnetic amorphous alloy and a thin strip of a nonmetal, and a thin strip of the Fe-based soft magnetic amorphous alloy 301 unwound from a spool 300 is laminated on the front and back sides of the thin strip of the Fe-based soft magnetic amorphous alloy 301 unwound from a spool 305, and the thin strip of the Fe-based soft magnetic amorphous alloy 301 is sandwiched between the thin strips of the nonmetal 306 and supplied to the rotary die cutter. FIG. 4 shows an external perspective view of the die cut roll. A plurality of cutting blades 351 are provided on the surface of the die cut roll 350. The cutting edge of the cutting blade 351 is flat and has a width of several μm to several tens of μm, and the cutting blade 351 presses the workpiece supplied to the rotary die cutter against the surface of the anvil roll 355, crushing and breaking the thin ribbon 301 of the Fe-based soft magnetic amorphous alloy. The thin plate 1 cut out from the workpiece is collected in a container 370 together with non-metallic scraps cut out from the workpiece. The workpiece that has passed through the rotary die cutter is taken up on a spool 360.

[0030] The non-metallic thin ribbon 306 functions as a buffer material and may be, for example, a film-like resin, Japanese paper, or Western paper having a thickness of 10 to 150 μm. The resin is preferably polyethylene, polyvinyl chloride, acrylic, polyethylene terephthalate, or polycarbonate.

[0031] Even if the cutting blade of the die-cut roll wears, no burrs protruding in the thickness direction of the thin plate are generated, so that a thin plate having a V-shaped side surface can be stably produced. Furthermore, when the cutting blade wears out, the thin plate is not punched, and a part of the end portion is likely to be connected to the thin ribbon of the Fe-based soft magnetic amorphous alloy. This state of separation can be used as an indicator of the degree of wear of the cutting blade, and the cutting blade can be corrected, so that maintenance and management of the thin ribbon processing device becomes easy. Note that the present invention is not limited to this, and a cutting method using a Thomson blade may also be used.

[0032] The thin plates obtained through the process of giving a certain shape to the Fe-based soft magnetic amorphous alloy ribbon can be stacked and integrated with an adhesive or the like. In the stacking process, it is preferable to prepare an alignment jig and a pressure plate according to the shape of the thin plates, stack the desired number of thin plates in the alignment jig, and stack the pressure plates above and below them to integrate them. In bonding between thin plates of Fe-based amorphous alloy, it is preferable to form a resin layer uniformly and without unevenness, but if the required adhesive strength is obtained, the resin layer may be formed partially. The resin can be applied to the thin plates of Fe-based amorphous alloy by dripping or spraying liquid resin onto the thin plates, or by immersing the thin plates in liquid resin. In addition, the thin plates of Fe-based soft magnetic amorphous alloy may be applied with a coater (coating device) before processing, or the ribbon may be immersed in liquid resin, and then the thin plates may be integrated through a process of giving a shape.

[0033] The resin used for bonding the thin plates is preferably an epoxy or acrylic resin, and among these, a resin with high heat resistance is more preferable.

[0034] The thinner the resin layer between the thin plates, the higher the space factor of the laminated core can be, which is preferable. In order to obtain a high space factor (80% to 98%) while obtaining the desired adhesive strength, the thickness is preferably about 1 μm to 5 μm, and more preferably within the range of 1 μm to 3 μm. Since no burrs protruding in the thickness direction are generated on the edges of the thin plates, the thickness of the resin layer can be made thin, and even if the thickness of the resin layer is made thin, bulkiness at the edges of the laminated core can be suppressed.

[0035] FIG. 8 shows a perspective view of another embodiment of a thin plate of an Fe-based soft magnetic amorphous alloy. The thin plate 1 shown in the figure is for a laminated core of a rotating electric machine, and has an annular portion 7 and a plurality of protrusions 6 arranged in rotational symmetry along its inner circumference. FIG. 9 is a partially enlarged perspective view of the thin plate. The thin plate 1 shown in the figure has a shape having a plurality of side surfaces 25 on the inner diameter side. By manufacturing such a thin plate 1 by the same means as the thin plate shown in FIG. 5, no burrs protruding in the thickness direction are generated at the edge of the thin plate 1, and the side surfaces 25 of the thin plate 1 can be inclined surfaces inclined in the thickness direction of the thin plate 1 from each of the front and back surfaces 20 as shown in FIG. 1, and can be formed into a V-shape tapered toward the end. The thin plate in the present invention is not particularly limited in shape and can be formed into various forms.

[0036] Fig. 10 shows a perspective view of a laminated core formed by stacking thin plates of an Fe-based soft magnetic amorphous alloy. The illustrated laminated core 10 is used as the stator of a rotating electric machine, and several hundred to several thousand thin plates 1 are stacked on top of each other. The annular portion 7 is used as the back yoke of the stator, and the protruding portions 6 become teeth. The obtained laminated core 10 can also be a laminated core in which an increase in eddy current loss due to short circuits between the thin plates 1 is suppressed.

[0037] Fig. 11 is a schematic diagram showing an example of a rotating electric machine using a laminated core 10 of the present invention. As shown in Fig. 11, a rotating electric machine 280 of the present invention has a rotor provided on the inner diameter side of a stator (laminated core) 10 with a gap therebetween. A plurality of permanent magnets 290 are arranged on the outer periphery of the rotor. The permanent magnets 290 are magnetized so that the side facing the stator 10 becomes a north pole or a south pole, and are arranged at equal angles so that the polarities of adjacent permanent magnets 290 are alternately reversed. Note that, although the rotor has eight poles in the embodiment shown in Fig. 11, the number of magnetic poles is not limited to this.

[0038] Stator windings 260 are provided on the teeth 6 of the stator 10, and a three-phase AC current based on the position of the magnetic poles of the rotor is supplied to the stator windings 260, causing the stator to generate a rotating magnetic field. The rotating electric machine operates as a rotating motor due to the permanent magnets 260 of the rotor and the rotating magnetic field. In the present invention, a rotating electric machine capable of operating with high efficiency can be realized by using a laminated iron core for the stator, which is made of a thin plate of an Fe-based soft magnetic amorphous alloy having a thickness of 10 to 50 μm and no burrs in the thickness direction. EXAMPLES

[0039] Metglas (registered trademark) 2605SA1 manufactured by Hitachi Metals, Ltd. was prepared as a ribbon of Fe-based soft magnetic amorphous alloy. The ribbon was long, with thicknesses of 25 μm and 32 μm and a width of 30 mm. The ribbon of Fe-based soft magnetic amorphous alloy was broken using a Thomson blade or a die-cut roll to produce a thin plate with the shape shown in FIG. 8. The outer dimensions of the thin plate were an outer diameter of 22 mm and an inner diameter of 10 mm.

[0040] Example 1 The Fe-based soft magnetic amorphous alloy ribbon was cut into a thin plate by the rotary die cutter described above. The workpiece was a 25 μm thick Fe-based soft magnetic amorphous alloy ribbon sandwiched between 13 μm thick polyethylene film as a cushioning material, and the anvil roll and die cut roll were brought close to each other, and the workpiece was passed through to produce a thin plate. The cutting edge of the die cut roll's press blade was 15 to 30 μm wide and flat, with a cutting edge angle of 30°.

[0041] Example 2 A thin plate was produced in the same manner as in Example 1, except that a thin ribbon of an Fe-based soft magnetic amorphous alloy having a thickness of 32 μm was used.

[0042] Example 3 A thin ribbon of Fe-based soft magnetic amorphous alloy with a thickness of 25 μm was broken with a Thomson blade to produce a thin plate. The cutting device to which the Thomson blade is attached has a drive mechanism that moves the Thomson blade up and down and a receiving table with a flat cutting surface on which the thin ribbon is placed, and can break the thin plate by moving the Thomson blade toward the cutting surface. The workpiece was a ribbon of Fe-based soft magnetic amorphous alloy sandwiched between 100 μm thick polyethylene films as a buffer material, and a pressure of 150 N was applied with the Thomson blade to break the ribbon to produce a thin plate. The cutting edge of the Thomson blade is also 20 μm wide and flat, with a cutting edge angle of 45°.

[0043] The side of the thin plate obtained in Examples 1 to 3 was observed from the front and back sides with a Keyence laser microscope VK-X1000. FIG. 12 shows a laser microscope photograph of the side of the front and back sides of the thin plate of Example 1. Each thin plate was cut, embedded in resin, and the side of the cut surface was exposed by polishing and observed. FIG. 13 shows a laser microscope photograph of the side of the cross section of the thin plate of Example 1. From the obtained observation photographs, each side had an inclined surface continuing from the front and back sides, the entire inclined surface was composed of a fracture surface due to ductile fracture, and the cross section had a tapered V-shape. In addition, no burrs protruding in the thickness direction caused by shear processing were confirmed in any of them. In the observation of the front and back sides of the thin plate, the distance L from the end of the V-shape of the side surface of the fracture surface was measured, and the minimum and maximum distance is shown in Table 1 as the fracture surface distance L.

[0044] [Table 1]

[0045] The thin plate of the Fe-based soft magnetic amorphous alloy of the present invention had a fracture surface in a region of about 10 to 100 μm on the side, and the cross section was tapered toward the end. The thin plate of Example 1 was observed at a magnification of 50 times using a laser microscope VK-X1000 manufactured by Keyence, with an evaluation region of 270 μm × 202 μm including the front and back surfaces and the inclined surface. Figure 14 shows the surface profile of the thin plate. No burrs protruding in the thickness direction were confirmed at the corners formed by the front and back surfaces 20 and the inclined surface 30. From this, it can be seen that in the laminated core formed by laminating the thin plates of the present invention, electrical short circuits are unlikely to occur between the layers, and the loss of the laminated core can be easily reduced. [Explanation of symbols]

[0046] 1. Thin plate of Fe-based soft magnetic amorphous alloy 5, 10 Laminated core 6 Convex 7 Circular Ring 18 Punch 19 Die 20 Front and back of thin plate 25 Thin Plate Side 30 Thin plate inclined surface 85 Fracture surface due to ductile fracture 120 Bali 131 Who 135 Shear Surface 138 Fracture surface 200 resin layer 260 Stator Winding 280 Rotating Electric Machine 290 Permanent Magnets 300 A spool wound with a ribbon of Fe-based soft magnetic amorphous alloy 301 Fe-based soft magnetic amorphous alloy ribbon 305 Spool of non-metallic ribbon 306 Nonmetallic ribbons 350 Die cut roll 351 Pushing blade 355 Anvil Roll 360 Spool with processed Fe-based soft magnetic amorphous alloy ribbon wound on it 370 Container for collecting processed thin plates

Claims

1. A thin sheet of an Fe-based soft magnetic amorphous alloy for a laminated core, The thin plate has a front, back and side surface opposite to each other and a thickness of 10 to 50 μm; The side surface has a fracture surface due to ductile fracture inclined from each of the front and back sides with respect to the thickness direction of the thin plate, A thin plate of an Fe-based soft magnetic amorphous alloy, which has a V-shape tapered toward one end in a cross section in the thickness direction of the thin plate.

2. A thin plate of the Fe-based soft magnetic amorphous alloy according to claim 1, A thin plate of an Fe-based soft magnetic amorphous alloy, all sides of the thin plate being V-shaped.

3. A thin plate of the Fe-based soft magnetic amorphous alloy according to claim 1 or 2, A thin plate of an Fe-based soft magnetic amorphous alloy, wherein a region extending from an end of a V-shape that is an outer edge of the thin plate to an inner side by a distance L of 5 μm or more is a fracture surface.

4. A laminated core, comprising thin plates of the Fe-based soft magnetic amorphous alloy according to any one of claims 1 to 3 stacked together.

5. A rotating electrical machine using the laminated core according to claim 4 in a stator or rotor.

6. A method of manufacturing a magnetic recording medium comprising: laminating a nonmetallic ribbon having a thickness of 10 to 150 μm on the front and back surfaces of a ribbon of an Fe-based soft magnetic amorphous alloy having a thickness of 10 to 50 μm; The Fe-based soft magnetic amorphous alloy ribbon is cut together with a nonmetallic ribbon by a rotary die cutter or a Thomson blade. Obtaining a thin plate having a front and back surface and a side surface, the side surface being inclined from each of the front and back surface sides in the thickness direction of the thin plate, and a V-shaped fracture surface tapered toward an end portion in a cross section in the thickness direction. A method for manufacturing a thin plate of an Fe-based soft magnetic amorphous alloy.

7. A method for manufacturing a thin plate of an Fe-based soft magnetic amorphous alloy as described in claim 6, characterized in that the cutting edge of the rotary die cutter or the Thomson blade is flat.

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