Magnetic plate laminate, manufacturing method therefor, and motor using this laminate

Provided is a magnetic plate laminate comprising a laminate formed by stacking a plurality of thin strips, and fastening members provided in apertures in the laminate. Also provided is a method for manufacturing a magnetic laminate wherein the thin strips are amorphous thin strips and the magnetic body laminate is subjected to heat treatment, thereby forming nano-crystalline grains in the thin strips. Also provided is a motor equipped with a stator formed by stacking a plurality of the magnetic plate laminates, a securing plate for securing the stator, and a rotor arranged in an opening in the middle of the stator.

TECHNICAL FIELD

The present invention relates to a magnetic-plate laminate formed by laminating soft magnetic thin strips, and also to a motor which uses this laminate as a stator.

BACKGROUND ART

Pure iron and electromagnetic steel plates are used for magnetic plates of iron cores (stators) for conventional motors. Furthermore, for a motor which aims higher efficiency, thin strips having an amorphous property or nanocrystal grains are used for an iron core (see, for example, Patent Literature (hereinafter, referred to as “PTL”) 1). The stator iron core according to PTL 1 is formed by machining first the amorphous alloy thin strips made by a liquid quenching method such as a single roll technique or a twin roll technique in a predetermined shape by a method such as winding, cutting, punching and etching.

By contrast with this,FIG. 16illustrates a perspective view of an amorphous lamination member51according to PTL 2. The lamination member51is manufactured by overlapping, from upper and lower sides, electromagnetic steel plates53on a plurality of sheets of the amorphous alloy thin strips52to which an adhesive has been applied, and heating and pressure-bonding the amorphous alloy thin strips52. Consequently, handling is easy.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

However, according to a configuration in PTL 1, when amorphous or crystallized soft magnetic thin strips are laminated to make parts such as iron cores, the thin strips are processed one by one. Therefore, the number of times of processing for each process performed until the thin belts reach a predetermined lamination thickness increases many times, and productivity is low.

Furthermore, according to a configuration in PTL 2 in FIG. 16, the adhesive enters between the layers of the amorphous thin strips, and therefore there are problems that a space factor is poor and motor efficiency becomes poor.

The present invention solves the conventional problems, and an object of the present invention is to provide a magnetic-plate laminate which has high productivity without impairing magnetic characteristics, and a motor which uses this laminate.

Solution to Problem

To achieve the above object, there is used A magnetic-plate laminate, including: a laminate in which a plurality of thin strips are laminated; and a fastening member that is provided in an opening of the laminate. Furthermore, there is used a method for manufacturing the magnetic-plate laminate, in which the magnetic-plate laminate in which the thin strips are amorphous thin strips is thermally processed to cause the stripes to have a nanocrystal grain. There is used a motor, including: a stator in which a plurality of the magnetic-plate laminates are laminated; a fixing plate that fixes the stator; and a rotor that is disposed in an opening at a center of the stator.

A magnetic-plate laminate according to the present invention can simultaneously handle a plurality of positioned thin strips and, consequently, not only has high productivity but also does not include a material which decreases a ratio of a magnetic member in a unit volume such as an adhesive between layers, therefore has a high space factor and can prevent a decrease in magnetic characteristics.

As a result, the magnetic-plate laminate according to the present invention has high productivity without impairing magnetic characteristics.

DESCRIPTION OF EMBODIMENTS

A magnetic-plate laminate and a motor according to embodiments will be described below with reference to the accompanying drawings. In addition, the substantially same components in the drawings will be assigned the same reference numerals.

FIG. 1Ais a side view of fastening member100awhich fastens magnetic-plate laminate1.FIGS. 1B to 1Dare schematic views illustrating a manufacturing process of magnetic-plate laminate1according to Embodiment 1, and, more specifically, illustrate that an eyelet structure is used as a metal fastening mechanism.

Fastening member100aincludes a plurality of planar portions2awhich are partitioned by cuts at both ends of hollow cylinder2. In this regard, eyelet structure3ais a structure that planar portions2aare located at the both ends of hollow cylinder2in a vertical direction of the cylinder. Eyelet structure3ais fitted in opening4formed in magnetic-plate laminate1formed by laminating thin strips which are magnetic bodies. Eyelet structure3aincludes planar portions2aat the both ends of hollow cylinder2so as not to be detached easily from opening4. As a result, eyelet structure3acan collectively fix magnetic-plate laminate1formed by laminating a plurality of thin strips. Furthermore, eyelet structure3ais also referred to as a grommet or an eyelet. In addition, hollow cylinder2may be a columnar type or a polygonal columnar shape.

FIGS. 1B to 1Dillustrate laminate1, hollow cylinder2, planar portions2aformed at cuts on hollow cylinder2, and opening4formed in magnetic-plate laminate1. Opening4is a hole which penetrates magnetic-plate laminate1. The fastening member inFIG. 1Ais inserted in this opening4.

Next, inFIG. 1C, laminated magnetic-plate laminate1is fixed by pressing mechanisms5, and eyelet fittings6are butted from upper and lower sides in arrow directions to push open planar portions2a.

Furthermore, inFIG. 1D, compressing fittings7perform compression from the arrow directions (from the upper and lower sides) to make planar portions2aface left and right directions to form eyelet structure3a. The compression may be height regulation which can keep the fixed height of the eyelet, or pressure regulation which can make the eyelet firm.

FIG. 2is a cross-sectional view illustrating a state where laminated magnetic-plate laminate1is fixed by eyelet structures3a.

Magnetic-plate laminate1is formed by laminating the thin strips. In this case, the thin strip is an amorphous magnetic plate. The plate thickness of the thin strip obtained in an amorphous state is usually between 10 and 100 μm. Furthermore, the thin strip may be an amorphous thin strip crystalized by heat processing.

A material of fastening member100ais desirably a non-magnetic material which is not influenced by a magnetic field from a viewpoint that this material does not influence magnetic characteristics of magnetic-plate laminate1. As this non-magnetic material, an iron-based material such as austenitic stainless steel, or a non-ferrous metal such as a cooper, a copper-based alloy such as brass, aluminum or an aluminum alloy, or an alloy of these metal can be used.

Eyelet structure3aof fastening member100amade of brass fixes 30 sheets of amorphous thin strips (thin strips) to handle as one magnetic-plate laminate1. The thicknesses of upper and lower planar portions2aof eyelet structure3aare 60 μm in total, and, when the thickness of the thin strip (thin strip) is 30 μm, a space factor indicating occupation of the thin strips in a lamination thickness direction is approximately 94%. As the plate thicknesses and the number of sheets of the thin strips are larger and planar portions2aare thinner, the space factor is higher. A lamination thickness limit of the thin strips depends on eyelet structure3a, and, as the lamination thickness is thicker, planar portions2aand thicker eyelet structure3aare necessary.

Eyelet structure3amay be formed in magnetic-plate laminate1of the crystalized thin strips or eyelet structure3amay be formed in magnetic-plate laminate1of the amorphous thin strips, then be thermally processed and crystallized.

A crystallization temperature varies based on a composition and is usually between 350° C. and 500° C., and when a nanocrystal grain whose diameter is several 10 nm or less is included in the thin strip, the thin strip has better soft magnetic characteristics than an amorphous member.

In addition, when crystallized from the amorphous state, the thin strip becomes fragile, and therefore when eyelet structure3ais formed after the crystallization, it is necessary to pay attention not to break the thin strips.

On the other hand, when an amorphous thin strip group is thermally processed after formation of eyelet structure3a, it is preferable to make a thermal gradient in a lamination direction small and make a heat processing temperature distribution in the lamination direction uniform. Furthermore, the quantity of heat of self-heating when the thin strips are crystallized from the amorphous state accumulates at a lamination center portion, and a temperature excessively rises. On the other hand, the quantity of heat of self-heating of the thin strips is correlated with the thickness. In view of this, the thickness of magnetic-plate laminate1is preferably the thickness equal to or less than 2.5 mm to suppress the excessive temperature rise. This shows that desired magnetic characteristics can be obtained. In this case, some of laminates1can be laminated to form one thick magnetic-plate laminate1.

When the entire thickness of magnetic-plate laminate1is 2.5 mm, and the plate thickness of one sheet of a thin strip is minimum 10 μm, 250 sheets of thin strips need to be laminated at maximum. Furthermore, a plurality of sheets of thin strips is laminated and manufactured to enhance productivity. The entire thickness in a case of two sheets of the laminated thin strips is 0.02 mm since the plate thickness of the thin strip is 10 μm.

When the above material is used as the material of fastening member100a, even if the thin strips are thermally processed and crystallized, eyelet structure3adoes not melt.

This eyelet structure3amakes it easy to transfer heat in the lamination direction of magnetic-plate laminate1and contributes to making the temperature gradient in the lamination direction small.

Furthermore, it is desirable to leave a trace of a heat effect such as an oxide on a surface of eyelet structure3a. A layer of the oxide has an insulation property, and consequently contributes to preventing electrical short-circuiting between laminated magnetic-plate laminate1and eyelet structure3a, and can reduce energy loss due to eddy current loss caused by short-circuiting in a magnetic device such as a motor.

FIG. 3is an external outlook view of fastening member100baccording to Embodiment 2. A difference ofFIG. 3from fastening member100ainFIG. 1Ais that planar portion2bis vertically bent on one side from hollow cylinder2from the beginning Planar portions2aare disposed in parallel to hollow cylinder2on the other side. Thus, there is an advantage that it is easy to position the fastening member in a thickness direction of magnetic-plate laminate1. A formation process of eyelet structure3aand a shape after formation of eyelet structure3aare equivalent to those inFIGS. 1D and 2. Matters which are not described are the same as those in Embodiment 1.

FIGS. 4A to 4Care schematic views illustrating a manufacturing process of magnetic-plate laminate1of a magnetic plate according to Embodiment 3. More specifically,FIGS. 4A to 4Cillustrate that fastening member100cis used for a metal fastening mechanism, and caulking structure3bis formed.

In this regard, a through-hole is not made in caulking structure3bunlike eyelet structure3a, and therefore planar portions10aare located at both ends of solid columnar body10in this structure. One end widens as planar portions10ato intend to collectively fix the laminated thin strips. Instead of a plurality of planar portions10a, one planar portion10ais formed unlike planar portions2aand2b. In this regard, planar portion10amay be divided into several portions. Matters which are not described are the same as those in Embodiment 1.

InFIG. 4B, fastening member100cis fixed by pressing mechanisms5, and compressing fittings7are butted from upper and lower sides in arrow directions.

Furthermore, inFIG. 4C, compressing fittings7can compress columnar body10in the arrow directions to form planar portions10aon the upper and lower sides of columnar body10in a vertical direction and form caulking structure3b.

FIG. 5is a cross-sectional view illustrating a state where laminated magnetic-plate laminate1is fixed by caulking structure3b. A material of fastening member100cwhich forms caulking structure3bis desirably a non-magnetic material which is not influenced by a magnetic field from a viewpoint that this material does not influence magnetic characteristics of magnetic-plate laminate1similar to eyelet structure3a. This is similar to Embodiment 1, and, for the material of fastening member100cwhich forms caulking structure3b, an iron-based material such as austenitic stainless steel, or a non-ferrous metal such as a cooper, a copper-based alloy such as brass, aluminum or an aluminum alloy, or an alloy of these can be used.

FIGS. 6A and 6Bare schematic views illustrating a process of forming eyelet structures3cof magnetic-plate laminate1of a magnetic plate according to Embodiment 4. InFIG. 6A, opening55is made by drill12at an axial center of one of two caulking structures3bformed in laminated magnetic-plate laminate1. InFIG. 6B, when openings55are made at two portions, eyelet structures3care formed. In this case, a cutting mark (irregularity24) is left in the inner wall of the opening of eyelet structure3c. Irregularity24is preferably 10 nm or more.

Thus, matters which can be changed from caulking structure3bto eyelet structure3cin the same process and are not described are the same as those in the above embodiments.

FIGS. 7A to 7Care schematic views illustrating a manufacturing process of magnetic-plate laminate1according to Embodiment 5, and illustrate magnetic-plate laminate1for which caulking structure3dis used. A difference ofFIGS. 7A to 7CfromFIGS. 4A to 4Cis that a columnar fastening member100dis used.

InFIG. 7A, fastening member100dwhich is longer than the depth of opening4and is larger than the volume of opening4is inserted in opening4of laminated magnetic-plate laminate1in an arrow direction.

InFIG. 7B, laminated magnetic-plate laminate1is fixed by pressing mechanisms5, and caulking fittings16having counterbored portions15are butted from upper and lower sides in arrow directions.

Furthermore, inFIG. 7C, caulking fittings16compress fastening member100din the arrow directions, so that part of fastening member100dplastically flow and is loaded to counterbored portions15to form guards on the upper and lower sides and fix laminated magnetic-plate laminate1by caulking structure3d. Furthermore, the shape of fastening member100dmay be a prismatic shape or a spherical shape other than the columnar shape. Matters which are not described are the same as those in the above embodiments.

FIG. 8is an enlarged cross-sectional view near caulking structure3dof magnetic-plate laminate1according to Embodiment 6. A non-ferrous material has lower hardness than an iron-based material as a material of caulking structure3d, and can be caulked with a small load.

Particularly when a low melting point alloy such as a solder is used as caulking structure3d, a yield stress is low and a melting point is also low. A heat processing temperature of 350° C. to 500° C. exceeds the melting points of multiple solders, and therefore part of caulking structure3dflows in gaps20of thin strips19, and leaves projection portions21of projection shapes. When these projection portions21enter between the layers of thin strips19, there are also advantages that there is little gap in a lamination direction, and a fixing state is more firm. Matters which are not described are the same as those in the above embodiments. Projection portions21are located on a side surface of the columnar portion of caulking structure3d. A plurality of projection portions21is preferably provided.

An eyelet structure also needs to include these projection portions21.

FIG. 9is an enlarged cross-sectional view near fastening member100dof a magnetic-plate laminate according to Embodiment 7. A difference of fastening member100dinFIG. 9from caulking structure3binFIG. 5is that an outer peripheral portion of fastening member100dis provided with insulation layer23. InFIG. 7A, by providing insulation layer23such as a resin which can deform on an outer peripheral portion of caulking member14, and performing caulking in the same process as those inFIGS. 7B and 7C, a structure inFIG. 9can be obtained. By providing insulation layer23on outer peripheral of fastening member100d, it is possible to prevent electrical short-circuiting between laminated magnetic-plate laminate1and fastening member100d, and reduce energy loss due to eddy current loss caused by short-circuiting in a magnetic device such as a motor. Matters which are not described are the same as those in the above embodiments.

In addition, preferably, above fastening members100ato100calso include insulation layers23on outer peripheral surfaces or inner peripheral surfaces of fastening members100ato100clikewise.

FIGS. 10A and 10Bare external outlook configuration diagrams of a motor formed by magnetic-plate laminate1of a magnetic plate according to Embodiment 8.FIG. 10Ais a side view of the motor, andFIG. 10Bis a top view of the motor.

InFIG. 10A, stator31which is a laminated object of thin strips is fixed to fixing plate32by bolts33, spring washers34, washers35and nuts36. InFIG. 10B, windings38are provided to portions which are called teeth (T-shaped protrusion portions) of stator31. Rotor37is installed on an inner diameter side (opening portion) of stator31.

FIGS. 11A and 11Bare cross-sectional configuration diagrams between A and A′ inFIG. 10B,FIG. 11Aillustrates a state without fixing bolts33andFIG. 11Billustrates a state with bolts33.

InFIG. 11A, laminates41of eyelet structures3aand3cwhich form stator31are positioned such that portions of eyelet structures3aand3care stacked on through-hole42for fastening fixing plate32, and are laminated at three stages. Metal fastening mechanisms (openings4and fastening members100aand100b) are linearly arranged in a thickness direction of stator31.

InFIG. 11B, laminates41of eyelet structures3aand3care fixed to fixing plate32by bolts33, spring washers34, washers35and nuts36. By inserting bolts33in eyelet structures3aand3cin openings4of laminates41, it is possible to prevent damages on end surfaces of the thin strips during insertion of the bolts33. Furthermore, by stacking and laminating eyelet structures3aand3c, fastening pressures of the bolts33locally work on the thin strips, so that it is possible to prevent a negative influence on magnetic characteristics of laminates41.

Laminates41are used for stator31. However, laminates41may be used for rotor37. A motor whose rotor37rotates around stator31may be used.

Furthermore, adhesive43is applied to an inner wall of opening4inside fastening member100eto couple laminates41of three stages. By adhering laminates41of eyelet structures3c, it is possible to handle stator31alone even if bolts are not used for fastening, so that handling becomes easier.

Adhesive43is used for coupling inFIG. 12. However, fastening members100emay be welded to each other or fastening members100emay be caulked to each other. Matters which are not described are the same as those in Embodiment 8.

FIGS. 13A and 13Bare external outlook configuration diagrams of a motor formed by a magnetic-plate laminate according to Embodiment 10,FIG. 13Ais a side view andFIG. 13Bis a top view. The motor inFIGS. 13A and 13Bis different from a motor inFIGS. 10A and 10Baccording to Embodiment 8. Difference points include that (1) stator31which is a laminated object of thin strips is fixed at three portions of fixing plate32by bolts33, spring washers34, washers35and nuts36, and (2) resin portions44loaded in openings4of the fastening members are provided at three portions. That T-shaped portions which are called teeth of stator31are wound by windings38and rotor37is installed on an inner diameter side of stator31is the same as that inFIGS. 10A and 10B.

FIG. 14is a cross-sectional configuration diagram between B and B′ in above FIG.13B, and illustrates a state where laminates45of eyelet structures100a,100band100eare laminated before fixing bolts33and resin portions44are inserted. Laminates45of the eyelet structures which form stator31are laminated at five stages such that through-holes46and hollow portions47of fastening members100eare alternately stacked. That is, fastening members100eadjacent on the upper and lower sides are located at different positions in a plan view of stator31. Alternatively, fastening members100eadjacent on the upper and lower sides are not combined.

This configuration provides an effect that upper and lower gaps48of laminated magnetic-plate laminate1narrow and a space factor is high compared to a case where eyelet structures3aand3care stacked and laminated at three states inFIG. 11Ain Embodiment 8.

FIG. 15is a cross-sectional configuration diagram between B and B′ in aboveFIG. 13B, and illustrates a state where laminates45of the eyelet structures are laminated and fixed after fixing bolts33and resin portions44are inserted. Laminates45of the eyelet structures are fixed to fixing plate32by bolts33, spring washers34, washers35and nuts36via through-holes46and hollow portions47of fastening members100e. Furthermore, resin portions44loaded to keep rigidity are formed in laminates45in which bolts33are not inserted. Even when resin portions44are hollow, other materials may be loaded. Matters which are not described are the same as those in Embodiments 8 and 9.

CONCLUSION

The embodiments can be combined. The eyelet members and the caulking members may be columns, columnar cylinders, square columns or elliptical columns.

In addition, the present disclosure includes any combination of optional embodiments and/or examples among the above-described various embodiments and/or examples, and can provide the effects of the respective embodiments and/or examples.

INDUSTRIAL APPLICABILITY

The magnetic-plate laminate according to the present invention can provide the magnetic-plate laminate which has high productivity without impairing magnetic characteristics. Consequently, the magnetic-plate laminate according to the present invention is useful as the stator of the motor. Furthermore, the magnetic-plate laminate according to the present invention is applicable for use in magnetic application electronic parts such as transformers other than motors.

REFERENCE SIGNS LIST