JP7833862B2 - Stacked core and method for manufacturing a stacked core - Google Patents

Description

This invention relates to a laminated core and a method for manufacturing a laminated core.

Conventionally, it is known that a laminated core is constructed by stacking two or more electromagnetic steel sheets. For example, a laminated core comprises a core back portion formed in an annular shape and teeth portions that protrude radially from the core back portion.
Generally, when adjacent electrical steel sheets are bonded together in the lamination direction using an adhesive, the adhesive shrinks during curing. Therefore, as the insulating coating hardens, compressive stress is applied to the electrical steel sheets. This compressive stress causes strain in the electrical steel sheets. In this case, depending on the bonding location, there is a risk that the magnetic properties of the laminated core may deteriorate.

In the technology of bonding and laminating electrical steel sheets using adhesives, a technique is known in which the adhesive is applied only to specific areas, particularly the core back periphery and the tooth tip, in order to consider the adverse effects of the compressive stress mentioned above (see, for example, Patent Documents 1 to 4).
Furthermore, there is a known technique for manufacturing a laminated core by laminating electromagnetic steel sheets equipped with an insulating coating that can be bonded (has adhesive properties) by heating and/or pressurizing, and then heating and pressurizing the laminated core (see, for example, Patent Documents 5 and 6).

International Publication No. 2020/129928 Japanese Patent Publication No. 2021-019376 Japanese Patent Publication No. 2010-136467 Japanese Patent Publication No. 2012-029494 Japanese Patent Publication No. 2012-171111 Japanese Patent Publication No. 2012-174739

As described above, while limiting the bonding area by applying adhesive only to specific locations is effective in avoiding unintended distortion, its effectiveness in laminated cores formed by bonding electrical steel sheets with adhesive insulating coatings by heating and/or pressurization remains unclear. When using electrical steel sheets with insulating coatings that are bondable by heating and/or pressurization (possessing adhesive properties), there is a need for an optimal coating configuration and manufacturing method to improve the characteristics of the laminated core.

This invention has been made in view of the above problems, and aims to provide a laminated core that suppresses the deterioration of magnetic properties caused by the bonding of adjacent electromagnetic steel sheets in the lamination direction, and a method for manufacturing a laminated core.

To solve the aforementioned problems, this invention proposes the following means.
The laminated core of the present invention is a laminated core in which a plurality of electromagnetic steel sheets coated with an adhesive insulating film are laminated in the lamination direction, wherein each electromagnetic steel sheet comprises a core back portion and a tooth portion projecting radially from the core back portion, and the radial tip portions of the tooth portions of adjacent electromagnetic steel sheets in the lamination direction, and the first circumferential portion of the core back portion, which is the portion of the core back portion opposite to the tooth portion in the radial direction, are bonded to each other by the insulating film, and the second circumferential portion of the core back portion of adjacent electromagnetic steel sheets in the lamination direction, other than the first circumferential portion, is not bonded to each other by the insulating film.
In this context, "having adhesive properties" means having the characteristic of melting and bonding when subjected to at least one of heating and/or pressurization. The first circumference of the core back portion refers to either the outer circumference (radially outer portion) or the inner circumference (radially inner portion) of the core back portion, and means the portion formed around the entire circumference of the core back portion.

For example, a rotating electric machine is constructed using a laminated core, and this rotating electric machine is operated. Generally, the magnetic flux lines generated in the rotating electric machine at this time have difficulty passing through the first circumference of the electrical steel sheet compared to the second circumference. Therefore, even if the first circumferences of adjacent core back portions in the lamination direction are bonded to each other with an insulating coating, the application of compressive stress to the second circumference, through which the magnetic flux lines pass more easily, is suppressed, thereby reducing the impact on the magnetic flux lines and preventing a decrease in the magnetic properties of the laminated core.
Furthermore, since the radial tips of the teeth of adjacent electrical steel sheets in the lamination direction are bonded to each other by an insulating coating, it is prevented that the tip of one tooth of adjacent electrical steel sheets in the lamination direction will not lift away from the tip of the other tooth. This suppresses a decrease in the magnetic properties of the laminated core.

Furthermore, in the laminated core, the circumferential ends of the teeth portions of adjacent electrical steel sheets in the lamination direction are bonded to each other by the insulating coating, and the portions of the teeth portions of adjacent electrical steel sheets in the lamination direction other than the tip and both end portions are not required to be bonded to each other by the insulating coating.
According to this invention, the circumferential ends of the teeth of adjacent electrical steel sheets in the lamination direction are bonded to each other by an insulating coating. This prevents the ends of the teeth of one adjacent electrical steel sheet from lifting away from the ends of the teeth of the other. This makes it possible to more reliably suppress the deterioration of the magnetic properties of the laminated core. Furthermore, the parts of the teeth of adjacent electrical steel sheets in the lamination direction other than the tip and both ends are not bonded to each other by an insulating coating. This makes it possible to suppress the deterioration of the magnetic properties of the laminated core by applying compressive stress to these parts.

Furthermore, in the laminated core, the first peripheral portion of the core back portion may be the outer peripheral portion of the core back portion.
According to this invention, when the laminated core is of the so-called inner rotor type, it is possible to suppress the deterioration of the magnetic properties of the laminated core.

Furthermore, according to this invention, the adhesive portions of adjacent electrical steel sheets in the lamination direction are bonded to each other by an insulating coating. That is, there is no adhesive, which is a substance with a different composition from the insulating coating, at the boundary between adjacent electrical steel sheets in the lamination direction, and the insulating coating covering the surface of each adjacent electrical steel sheet is integrated and homogeneous. As a result, compared to conventional laminated cores where an adhesive, which is a substance different from the insulating coating, is applied to form partial adhesive portions, the generation of compressive stress associated with localized bonding is suppressed, and the deterioration of the magnetic properties of the laminated core can be suppressed.

Furthermore, in an adhesive core where localized bonding areas are formed between adjacent electromagnetic steel sheets in the lamination direction by localized heating and/or pressurization, the non-bonded areas are in a state of strong contact between adjacent electromagnetic steel sheets in the lamination direction. That is, the combined thickness of the opposing insulating coatings covering the surfaces of adjacent electromagnetic steel sheets in the lamination direction in the non-bonded areas is substantially the same as the thickness of the insulating coating that became homogenized and integrated from the insulating coatings covering the surfaces of each adjacent electromagnetic steel sheet in the lamination direction in the bonded areas. On the other hand, in a conventional laminated core where a partial bonding area is formed by applying an adhesive, which is a different substance from the insulating coating, the thickness of the bonding area increases by the thickness of the applied adhesive. As a result, a gap equivalent to the thickness of the adhesive is formed between the non-bonded areas of adjacent electromagnetic steel sheets in the lamination direction, or if there is contact, it is a very weak contact state. Consequently, in this invention, when the laminated core is assembled to a rotating electric machine and operates, unintended vibrations in the non-bonded areas are suppressed, the rotation of the rotor is stabilized, and the deterioration of the overall magnetic properties of the rotating electric machine is suppressed.

Furthermore, the present invention relates to a method for manufacturing a laminated core , wherein a plurality of electromagnetic steel sheets coated with an insulating film having adhesive properties are laminated in the lamination direction, and the electromagnetic steel sheet comprises a core back portion and a tooth portion projecting radially from the core back portion, and the method comprises a coating step of applying a masking agent to at least the portion of the tooth portion of the electromagnetic steel sheet other than the radial tip portion and both circumferential ends, and to the second circumferential portion of the core back portion which is the portion on the tooth portion side in the radial direction, and a lamination step of laminating the plurality of electromagnetic steel sheets, and the lamination direction The adhesive step involves applying the insulating coating to adjacent electrical steel sheets in the stacking direction, thereby bonding the tip portions of the teeth portions and the first circumferential portions of the core back portion, excluding the second circumferential portion, to each other with the insulating coating, wherein in the adhesive step, at least the portions of the teeth portions other than the radial tip portions and both circumferential end portions, and the second circumferential portion of the core back portion, to each other with the insulating coating.
In this context, the second circumference of the core back portion refers to either the inner circumference (the radially inner portion) or the outer circumference (the radially outer portion) of the core back portion, and means the portion formed around the entire circumference of the core back portion.

For example, a rotating electric machine is constructed using a laminated core, and this rotating electric machine is operated. Generally, for parts of the electromagnetic steel sheet to which a masking agent is applied, the adhesive ability of the insulating coating is not exhibited even if the insulating coating is pressurized or heated. On the other hand, for parts of the electromagnetic steel sheet to which a masking agent is not applied, if the insulating coating is pressurized or heated and the adhesive ability of the insulating coating is exhibited, adjacent electromagnetic steel sheets in the lamination direction are bonded to each other by the insulating coating. Also, magnetic flux lines generated in a rotating electric machine have difficulty passing through the first circumference compared to the second circumference. Therefore, multiple electromagnetic steel sheets to which a masking agent is applied in the coating process are laminated in the lamination process. Then, even if the first circumferences of adjacent core back portions in the lamination direction are bonded to each other by the insulating coating in the bonding process, the application of compressive stress to the second circumference, which has an easier path for magnetic flux lines, is suppressed, thereby reducing the impact on the magnetic flux lines and preventing a decrease in the magnetic properties of the laminated core.
Furthermore, during the bonding process, the radial tips of the teeth of adjacent electrical steel sheets in the lamination direction are bonded to each other by an insulating coating. This prevents the tip of one tooth from lifting away from the tip of the other tooth in adjacent electrical steel sheets in the lamination direction. This suppresses a decrease in the magnetic properties of the laminated core.

In adhesive cores manufactured by a method that applies a masking agent to form non-adherent areas between adjacent electrical steel sheets in the lamination direction, these non-adherent areas are in strong contact with adjacent electrical steel sheets in the lamination direction. That is, although a masking agent exists between the insulating coatings covering the surfaces of adjacent electrical steel sheets in the lamination direction, the combined thickness of the insulating coating and masking agent in the non-adherent areas is substantially the same as the thickness of the insulating coating in the adhesive areas. On the other hand, in conventional laminated cores where an adhesive, a substance different from the insulating coating, is applied to form partial adhesive areas, the thickness of the adhesive area increases by the thickness of the applied adhesive. Therefore, a gap equivalent to the thickness of the adhesive is formed between the non-adherent areas of adjacent electrical steel sheets in the lamination direction, or if there is contact, it is a very weak contact. As a result, in this invention, when the laminated core is assembled to a rotating electric machine and operates, unintended vibrations of the non-adherent areas are suppressed, the rotation of the rotor is stabilized, and the deterioration of the overall magnetic properties of the rotating electric machine is suppressed.

Furthermore, in the method for manufacturing the laminated core, in the coating step, the masking agent is applied to the portion of the tooth portion of the electromagnetic steel sheet other than the radial tip and the circumferential ends on both sides, and in the bonding step, the adhesive ability of the insulating coating is exerted on adjacent electromagnetic steel sheets in the lamination direction, thereby bonding the circumferential ends on both sides of the tooth portion of adjacent electromagnetic steel sheets in the lamination direction to each other with the insulating coating, and it is not necessary for the portion of the tooth portion of adjacent electromagnetic steel sheets in the lamination direction other than the tip and the circumferential ends on both sides to be bonded to each other with the insulating coating.
According to this invention, in the bonding process, the circumferential ends of the teeth of adjacent electrical steel sheets in the lamination direction are bonded to each other by an insulating coating. This prevents the ends of the teeth of one adjacent electrical steel sheet from lifting away from the ends of the teeth of the other. This makes it possible to more reliably suppress the deterioration of the magnetic properties of the laminated core. Furthermore, in the bonding process, the parts of the teeth of adjacent electrical steel sheets in the lamination direction other than the tip and both ends are not bonded to each other by the insulating coating. This makes it possible to suppress the deterioration of the magnetic properties of the laminated core by preventing compressive stress from being applied to these parts.

Furthermore, in the method for manufacturing the laminated core, the masking agent may be applied by a roll during the coating step.
According to this invention, a masking agent can be accurately applied to each position on the electrical steel sheet.

Furthermore, in the method for manufacturing the laminated core, the masking agent may be applied in the mold during the coating step.
According to this invention, for example, when punching out an electrical steel sheet from a material for forming an electrical steel sheet using a die, it is possible to suppress misalignment of the position where the masking agent is applied to the electrical steel sheet.

Furthermore, in the method for manufacturing the laminated core, the first peripheral portion of the core back portion may be the outer peripheral portion of the core back portion.
According to this invention, when the laminated core is of the so-called inner rotor type, it is possible to suppress the deterioration of the magnetic properties of the laminated core.

According to the laminated core and manufacturing method of the present invention, it is possible to suppress the deterioration of magnetic properties caused by the bonding of adjacent electromagnetic steel sheets in the lamination direction.

This is a cross-sectional view of a rotating electric machine equipped with a laminated core according to one embodiment of the present invention. This is a side view of the same stacked core. This is a cross-sectional view taken along line A-A in Figure 2. This is a plan view of the material forming the laminated core. This is a cross-sectional view taken along line B-B in Figure 4. This is an enlarged view of section C in Figure 5. This is a side view of a manufacturing apparatus preferably used in a method for manufacturing a laminated core according to one embodiment of the present invention. This flowchart shows the manufacturing method for the laminated core. This diagram illustrates the masking agent applied to the electrical steel sheet during the coating process of the manufacturing method for the laminated core. This diagram illustrates the magnetic flux lines generated in the rotating electric machine. This is a side view of the main part of the first modified example of the manufacturing apparatus. This is a side view of the main part of a second modified example of the manufacturing apparatus. This is a side view of the main part of a third modified example of the manufacturing apparatus.

The following describes a laminated core according to one embodiment of the present invention, a rotating electric machine equipped with this laminated core, and the material forming this laminated core, with reference to the drawings. In this embodiment, an electric motor, specifically an AC motor, more specifically a synchronous motor, and even more specifically a permanent magnet field motor, will be used as an example of the rotating electric machine. This type of electric motor is suitably used, for example, in electric vehicles.

(Rotating electric machine 10)
As shown in Figure 1, the rotating electric machine 10 comprises a stator 20, a rotor 30, a case 50, and a rotating shaft 60. The stator 20 and rotor 30 are housed within the case 50. The stator 20 is fixed within the case 50.
In this embodiment, the rotating electric machine 10 is an inner rotor type in which the rotor 30 is located radially inward of the stator 20. However, the rotating electric machine 10 may also be an outer rotor type in which the rotor 30 is located outside of the stator 20. Furthermore, in this embodiment, the rotating electric machine 10 is a 4-pole, 24-slot three-phase AC motor. However, the number of poles, the number of slots, the number of phases, etc., can be changed as appropriate.
The rotating electric machine 10 can rotate at a rotational speed of 3000 rpm by applying an excitation current with an effective value of 10 A and a frequency of 100 Hz to each phase, for example.

The stator 20 comprises a laminated core for the stator (hereinafter referred to as the stator core) 21 and windings (not shown).
The stator core 21 (electromagnetic steel sheet 40, described later) comprises an annular core back portion 22 and a plurality of teeth portions 23.
In the following, the direction of the central axis O of the stator core 21 (or core back portion 22) is referred to as the axial direction, the radial direction of the stator core 21 (or core back portion 22) (the direction perpendicular to the central axis O) is referred to as the radial direction, and the circumferential direction of the stator core 21 (or core back portion 22) (the direction that rotates around the central axis O) is referred to as the circumferential direction.

The core back portion 22 is formed in an annular shape in a plan view of the stator 20 as seen from the axial direction.
Multiple teeth portions 23 protrude radially inward from the inner circumference of the core back portion 22 (towards the central axis O of the core back portion 22 along the radial direction).
As shown in Figures 1 and 3, the teeth portion 23 comprises a main body portion 25, a round portion 26, and a flange portion 27. In Figure 3, the adhesive portion 3a formed by the insulating coating 3, which will be described later, is shown with hatching. Figure 3 does not show the permanent magnet 32 and through hole 33, which will be described later.
As shown in Figure 3, the main body portion 25 has a rectangular shape that is elongated in the radial direction when viewed in the axial direction. The round portion 26 connects the radial base end of the main body portion 25 to the inner peripheral edge of the core back portion 22. The round portion 26 is provided on both sides of the main body portion 25 in the circumferential direction. The round portion 26 is recessed radially outward and in an oblique direction toward the main body portion 25 in the circumferential direction.
The flange portion 27 protrudes from the radial tip of the main body portion 25 to both sides in the circumferential direction.

As shown in Figure 1, the multiple teeth portions 23 are arranged at equal angular intervals in the circumferential direction. In this embodiment, 24 teeth portions 23 are provided at 15-degree intervals around the central axis O. The multiple teeth portions 23 are formed to have the same shape and size as each other. Therefore, the multiple teeth portions 23 have the same thickness dimension as each other.
The winding is wound around the teeth portion 23. The winding may be a concentrated winding or a distributed winding.

The rotor 30 is positioned radially inward relative to the stator 20 (stator core 21). The rotor 30 comprises a rotor core 31 and a plurality of permanent magnets 32.
The rotor core 31 is formed in an annular (ring-shaped) form and is arranged coaxially with the stator 20. The rotating shaft 60 is located inside the rotor core 31. The rotating shaft 60 is fixed to the rotor core 31.
Multiple permanent magnets 32 are fixed to the rotor core 31. The multiple permanent magnets 32 are arranged at equal angular intervals in the circumferential direction. In this embodiment, four permanent magnets 32 are provided at 90-degree intervals around the central axis O.

In this embodiment, an embedded magnet type motor is used as the permanent magnet field motor. The rotor core 31 has a plurality of through holes 33 that penetrate the rotor core 31 in the axial direction. The plurality of through holes 33 are provided corresponding to the arrangement of the plurality of permanent magnets 32. Each permanent magnet 32 is fixed to the rotor core 31 while positioned within its corresponding through hole 33. The fixing of each permanent magnet 32 to the rotor core 31 can be achieved, for example, by bonding the outer surface of the permanent magnet 32 to the inner surface of the through hole 33 with an adhesive. Note that a surface magnet type motor may be used instead of the embedded magnet type as the permanent magnet field motor.

The stator core 21 and rotor core 31 are both laminated cores. For example, as shown in Figure 2, the stator core 21 is formed by laminating multiple electromagnetic steel sheets 40 in the lamination direction. The lamination direction is the axial direction.

The stacking thickness (total length along the central axis O) of the stator core 21 and rotor core 31 is, for example, 50.0 mm. The outer diameter of the stator core 21 is, for example, 250.0 mm. The inner diameter of the stator core 21 is, for example, 165.0 mm. The outer diameter of the rotor core 31 is, for example, 163.0 mm. The inner diameter of the rotor core 31 is, for example, 30.0 mm. However, these values are examples only, and the stacking thickness, outer diameter, and inner diameter of the stator core 21, and the stacking thickness, outer diameter, and inner diameter of the rotor core 31 are not limited to these values. Here, the inner diameter of the stator core 21 is based on the tip of the tooth portion 23 in the stator core 21. That is, the inner diameter of the stator core 21 is the diameter of a virtual circle inscribed in the tip of all the tooth portions 23.

Each electrical steel sheet 40 forming the stator core 21 and rotor core 31 is formed, for example, by punching out material 1 as shown in Figures 4 to 6. Material 1 is a steel sheet (electrical steel sheet) that serves as the base material for the electrical steel sheets 40. Examples of material 1 include strip-shaped steel sheets and cut sheets.
Although we are in the middle of explaining the laminated core, we will now describe material 1. In this specification, the strip-shaped steel sheet that serves as the base material for the electrical steel sheet 40 may be referred to as material 1. The steel sheet that has been punched out from material 1 to form the shape used for the laminated core may be referred to as electrical steel sheet 40.

Each electrical steel sheet 40 forming the stator core 21 and rotor core 31 is formed, for example, by punching out material 1 as shown in Figures 4 to 6. Material 1 is a steel sheet (electrical steel sheet) that serves as the base material for the electrical steel sheets 40. Examples of material 1 include strip-shaped steel sheets and cut sheets.
Although we are in the middle of explaining the laminated core, we will now describe material 1. In this specification, the strip-shaped steel sheet that serves as the base material for the electrical steel sheet 40 may be referred to as material 1. The steel sheet that has been punched out from material 1 to form the shape used for the laminated core may be referred to as electrical steel sheet 40.

(Material 1)
Material 1 is handled, for example, in a state wound onto a coil 1A (see Figure 7). In this embodiment, non-oriented electrical steel sheet is used as material 1. As the non-oriented electrical steel sheet, non-oriented electrical steel strip according to JIS C 2552:2014 can be used. However, grain-oriented electrical steel sheet may be used as material 1 instead of non-oriented electrical steel sheet. In this case, grain-oriented electrical steel strip according to JIS C 2553:2019 can be used as the grain-oriented electrical steel sheet. Alternatively, non-oriented thin electrical steel strip or grain-oriented thin electrical steel strip according to JIS C 2558:2015 can be used as material 1.

The upper and lower limits of the average plate thickness t0 of material 1 are set, for example, as follows, taking into consideration the case where material 1 is used as an electrical steel sheet 40.
As material 1 becomes thinner, the manufacturing cost of material 1 increases. Therefore, considering the manufacturing cost, the lower limit of the average plate thickness t0 of material 1 is 0.10 mm, preferably 0.15 mm, and more preferably 0.18 mm.
On the other hand, if material 1 is too thick, the manufacturing cost will be good, but when material 1 is used as an electrical steel sheet 40, the eddy current loss will increase and the core iron loss will deteriorate. Therefore, considering the core iron loss and manufacturing cost, the upper limit of the average plate thickness t0 of material 1 is 0.65 mm, preferably 0.35 mm, and more preferably 0.30 mm.
As an example of an average plate thickness t0 of material 1 that satisfies the above range, 0.20 mm can be used.

The average thickness t0 of material 1 includes not only the thickness of the base steel plate 2 (described later) but also the thickness of the insulating coating 3. Furthermore, the measurement method for the average thickness t0 of material 1 can be, for example, the following: For example, if material 1 is wound into the shape of a coil 1A, at least a portion of material 1 is unwound into a flat plate shape. A predetermined position in the longitudinal direction of material 1 (for example, a position 10% of the total length of material 1 from the longitudinal edge of material 1) is selected. At this selected position, material 1 is divided into five regions along its width. The thickness of material 1 is measured at four locations that form the boundaries of these five regions. The average value of the thicknesses at these four locations can be taken as the average thickness t0 of material 1.

The upper and lower limits for the average thickness t0 of material 1 can naturally be used as the upper and lower limits for the average thickness t0 of the electrical steel sheet 40. The measurement method for the average thickness t0 of the electrical steel sheet 40 is, for example, as follows: For example, the stacked thickness of the laminated core is measured at four locations with equal spacing in the circumferential direction (i.e., at 90-degree intervals around the central axis O). The thickness per sheet is calculated by dividing each of the four measured stacked thicknesses by the number of laminated electrical steel sheets 40. The average of the four thicknesses can be used as the average thickness t0 of the electrical steel sheet 40.

As shown in Figures 5 and 6, the material 1 comprises a base steel sheet 2 and an insulating coating 3. The material 1 is formed by covering both sides of a strip-shaped base steel sheet 2 with the insulating coating 3. In this embodiment, the majority of the material 1 is formed from the base steel sheet 2, and a thinner insulating coating 3 is laminated on the surface of the base steel sheet 2.

The chemical composition of the base steel sheet 2 contains 2.5% to 4.5% Si by mass, as shown below in mass percent. By setting the chemical composition within this range, the yield strength of the material 1 (electrical steel sheet 40) can be set, for example, to 380 MPa or more and 540 MPa or less.

Si: 2.5% to 4.5%
Al: 0.001% to 3.0%
Mn: 0.05% to 5.0%
Remainder: Fe and impurities

When material 1 is used as an electrical steel sheet 40, the insulating coating 3 provides insulation between adjacent electrical steel sheets 40 in the lamination direction. In this embodiment, the insulating coating 3 also has adhesive properties (self-fusing function) and adheres adjacent electrical steel sheets 40 in the lamination direction. More specifically, the insulating coating 3 is fused by applying pressure and/or heating.
The insulating coating 3 may be a single-layer structure or a multi-layer structure. More specifically, for example, the insulating coating 3 may be a single-layer structure that combines insulating performance and adhesive properties, or it may be a multi-layer structure including a base insulating coating with excellent insulating performance and a top insulating coating with excellent adhesive performance.

For example, the insulating coating 3 contains an epoxy resin and a curing agent.
Any epoxy resin that has two or more epoxy groups in a single molecule can be used without particular limitations. Examples of such epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, triphenylmethane type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, acrylic acid modified epoxy resin (epoxy acrylate), phosphorus-containing epoxy resin, and halogens thereof (such as brominated epoxy resin) and hydrogenated products. These epoxy resins may be used individually or in combination of two or more types.

The coating composition for electrical steel sheets used to form the insulating film 3 may contain acrylic resin.
The acrylic resin is not particularly limited. Examples of monomers used in the acrylic resin include unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and hydroxypropyl (meth)acrylate. Note that (meth)acrylate means acrylate or methacrylate. The acrylic resin may be used alone or in combination of two or more types.

Acrylic resins may contain constituent units derived from monomers other than acrylic monomers. Examples of other monomers include ethylene, propylene, and styrene. These other monomers may be used individually or in combination of two or more.

When using acrylic resin, it may be used as an acrylic-modified epoxy resin obtained by grafting acrylic resin onto an epoxy resin. In coating compositions for electrical steel sheets, it may be included as a monomer for forming the acrylic resin.

As epoxy resin curing agents, latent, heat-curing types can be used. Examples include aromatic polyamines, acid anhydrides, phenolic curing agents, dicyandiamides, boron trifluoride-amine complexes, and organic acid hydrazides. Examples of aromatic polyamines include metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Examples of phenolic curing agents include phenol novolac resins, cresol novolac resins, bisphenol novolac resins, triazine-modified phenol novolac resins, and phenol resol resins. Among these, phenolic curing agents are preferred, and phenol resol resins are more preferred. Epoxy resin curing agents may be used individually or in combination of two or more.

The content of the epoxy resin curing agent in the coating composition for electrical steel sheets is preferably 5 to 35 parts by mass, and more preferably 10 to 30 parts by mass, per 100 parts by mass of epoxy resin.

The coating composition for electrical steel sheets may contain additives such as curing accelerators (curing catalysts), emulsifiers, and defoamers. Only one additive may be used, or two or more may be used in combination.

The epoxy resin content is preferably, for example, 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 50 to 70% by mass, relative to the total mass of the coating composition for electrical steel sheets. If the epoxy resin content is above the lower limit, the adhesive strength of the electrical steel sheet 40 can be further increased. If the epoxy resin content is below the upper limit, the stress strain of the electrical steel sheet 40 can be further relieved.

The epoxy resin curing agent of this embodiment contains a phenol-based curing agent (A) and an amine-based curing agent (B).
Examples of phenolic curing agents (A) include phenol novolac resin, cresol novolac resin, bisphenol novolac resin, triazine-modified phenol novolac resin, phenol resol resin, and cresol naphthol formaldehyde condensate.
The phenolic curing agent (A) may be used alone or in combination of two or more types.

The amine-based curing agent (B) is one or more selected from aromatic amines and dicyandiamides.
Examples of aromatic amines include metaxylylenediamine, metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.
Dicyandiamide is also known as a latent curing agent. Latent curing agents, when compounded with epoxy resins, can be stored stably at room temperature and have the ability to rapidly cure the resin composition with heat, light, pressure, etc. Dicyandiamide is a colorless, orthorhombic or plate-like crystal with a melting point of 207–210°C. It reacts with epoxy resins at 160–180°C and cures in 20–60 minutes.
Dicyandiamide is preferably used in combination with a curing accelerator. Examples of curing accelerators include tertiary amines, imidazoles, and aromatic amines.
The amine-based curing agent (B) may be used alone or in combination of two or more types.

In this embodiment, the insulating coating 3 completely covers both sides of the base steel plate 2 without any gaps. However, within the range where the aforementioned insulating performance and adhesive properties are ensured, the insulating coating 3 does not necessarily have to completely cover both sides of the base steel plate 2. In other words, the insulating coating 3 may be intermittently provided on the surface of the base steel plate 2.

In this embodiment, the insulating coating 3 completely covers both sides of the base steel plate 2 without any gaps. However, within the range in which the aforementioned insulating performance and adhesive performance are ensured, some layers of the insulating coating 3 do not need to completely cover both sides of the base steel plate 2 without any gaps. In other words, some layers of the insulating coating 3 may be intermittently provided on the surface of the base steel plate 2.
However, in order to ensure insulation performance, both sides of the base steel sheet 2 must be covered with an insulating coating 3 so that the entire surface is not exposed. Specifically, if the insulating coating 3 does not have a base insulating coating with superior insulation performance and is a single-layer structure that combines insulation performance and adhesive properties, then the insulating coating 3 must be formed without gaps over the entire surface of the base steel sheet 2. On the other hand, if the insulating coating 3 is a multi-layer structure including a base insulating coating with superior insulation performance and a top insulating coating with superior adhesive properties, then in addition to forming both the base insulating coating and the top insulating coating without gaps over the entire surface of the base steel sheet 2, it is also possible to form the base insulating coating without gaps over the entire surface of the base steel sheet and provide the top insulating coating intermittently, thereby achieving both insulation performance and adhesive properties.

When an insulating coating with adhesive properties is intermittently provided on the surface of the base steel sheet 2, it is preferable that the spacing of the areas where the insulating coating covers the surface of the base steel sheet 2 is relatively small compared to the size of the areas that become adhesive parts in this invention, i.e., the first peripheral portion of the core back portion 22, the tip portion or side end portion of the teeth portion 23. For example, the intermittent covering form of the insulating coating on the plate surface may be dots, stripes, grids, etc., but the spacing (period) therebetween should be sufficiently smaller than the size of the adhesive portion. For example, it should be 1/3 or less of the minimum width of the adhesive portion. Preferably, it should be 1/5 or less, and more preferably 1/10 or less.
When the present invention is applied to an electromagnetic steel sheet 40 in which the insulating coating is intermittently provided on the surface of a base steel sheet 2, the adhesive portion in the present invention may, strictly speaking, have intermittently existing adhesive and non-adhesive regions (regions in which the insulating coating itself, which has adhesive properties, does not exist) depending on the degree of overlap of the insulating coatings of adjacent electromagnetic steel sheets 40 in the lamination direction. Even in such a situation, if the gap is sufficiently small compared to the adhesive portion, the region intended to be bonded at the first circumference, tip, or side end can be considered as a substantial single adhesive portion, and in the present invention, the region intended to be bonded is judged to be a substantial single adhesive portion.

The coating composition for forming the underlying insulating film is not particularly limited; for example, general treatment agents such as chromic acid-containing treatment agents and phosphate-containing treatment agents can be used.

An insulating coating with adhesive properties is formed by applying the aforementioned coating composition for electrical steel sheets onto a base steel sheet. An insulating coating with adhesive properties may be, for example, a single-layer insulating coating possessing both insulating and adhesive properties, or a top insulating coating applied on a base insulating coating. Before heat bonding during the manufacturing of laminated cores, the insulating coating with adhesive properties is in an uncured or semi-cured state (Stage B), and the curing reaction progresses due to heating during heat bonding, resulting in the development of adhesive properties.

The upper and lower limits of the average thickness t1 of the insulating coating 3 are set, for example, as follows, taking into consideration the case where material 1 is used as an electrical steel sheet 40.
When material 1 is used as an electrical steel sheet 40, the average thickness t1 of the insulating coating 3 (thickness per side of the electrical steel sheet 40 (material 1)) is adjusted to ensure insulation performance and adhesive performance between the electrical steel sheets 40 that are laminated together.
In the case of a single-layer insulating coating 3, the average thickness t1 of the insulating coating 3 (thickness per side of the electromagnetic steel sheet 40 (material 1)) can be, for example, 1.5 μm or more and 8.0 μm or less.
In the case of a multi-layered insulating coating 3, the average thickness of the base insulating coating can be, for example, 0.3 μm or more and 1.2 μm or less, and preferably 0.7 μm or more and 0.9 μm or less. The average thickness of the top insulating coating can be, for example, 1.5 μm or more and 8.0 μm or less.
Furthermore, the method for measuring the average thickness t1 of the insulating coating 3 on material 1 can be the same as for the average plate thickness t0 of material 1; the thickness of the insulating coating 3 at multiple locations can be determined, and the average of these thicknesses can be used to determine the average thickness.

The upper and lower limits for the average thickness t1 of the insulating coating 3 in material 1 can naturally be used as the upper and lower limits for the average thickness t1 of the insulating coating 3 in the electromagnetic steel sheet 40. The method for measuring the average thickness t1 of the insulating coating 3 in the electromagnetic steel sheet 40 can be, for example, the following measurement method. For example, among the multiple electromagnetic steel sheets forming the laminated core, select the electromagnetic steel sheet 40 located on the outermost side in the lamination direction (the electromagnetic steel sheet 40 whose surface is exposed in the lamination direction). On the surface of the selected electromagnetic steel sheet 40, select a predetermined position in the radial direction (for example, the position exactly midway (center) between the inner and outer edges of the electromagnetic steel sheet 40). At the selected position, measure the thickness of the insulating coating 3 of the electromagnetic steel sheet 40 at four locations with equal spacing in the circumferential direction (i.e., at 90-degree intervals around the central axis O). The average value of the thicknesses measured at the four locations can be taken as the average thickness t1 of the insulating coating 3.
The reason why the average thickness t1 of the insulating film 3 was measured on the outermost electrical steel sheet 40 in the lamination direction is that the insulating film 3 is manufactured in such a way that its thickness hardly changes at the lamination position along the lamination direction of the electrical steel sheet 40.

By punching out material 1 as described above, electrical steel sheets 40 are manufactured, and laminated cores (stator core 21 and rotor core 31) are manufactured from these electrical steel sheets 40.

As shown in Figure 3, the radial tip portions 23a of the teeth portions 23 of adjacent electrical steel sheets 40 in the stacking direction are bonded to each other by adhesive portions 3a formed by the insulating coating 3. The adhesive portions 3a are formed by heating and/or pressurizing the insulating coating 3. In this example, the tip portions 23a of the teeth portions 23 include a pair of flange portions 27, and the adhesive portions 3a are formed on the pair of flange portions 27.
Similarly, the circumferential ends 23b of the teeth portions 23 of adjacent electrical steel sheets 40 in the stacking direction are bonded to each other by an adhesive portion 3a (insulating coating 3).
In this example, adhesive portions 3a are formed on the main body portion 25 and the round portion 26 of the teeth portion 23, respectively. Preferably, the pair of side ends 23b formed on each teeth portion 23 are not in contact with each other.

Here, the portion of the tooth portion 23 other than the tip portion 23a and both end portions 23b is referred to as the central portion 23c. The central portions 23c of the tooth portions 23 of adjacent electrical steel sheets 40 in the lamination direction are not bonded to each other by the adhesive portion 3a. A masking agent (not shown) may be placed on the surface of the central portion 23c of the tooth portion 23. For example, colloidal silica, an organic solvent, etc., can be used as the masking agent. This masking agent eliminates (does not exhibit) the adhesive ability of the insulating coating 3. The central portions 23c of the tooth portions 23 of adjacent electrical steel sheets 40 in the lamination direction may be in contact with each other via the masking agent.

Here, the portion of the core back portion 22 opposite to the teeth portion 23 in the radial direction is called the outer circumference portion (first circumference portion) 22a. The outer circumference portion 22a is formed on the radially outer portion of the core back portion 22 and extends around the entire circumference of the core back portion 22. The portion of the core back portion 22 other than the outer circumference portion 22a is called the inner circumference portion (second circumference portion) 22b. The inner circumference portion 22b is the portion of the core back portion 22 that is on the radially teeth portion 23 side. The inner circumference portion 22b is formed on the radially inner portion of the core back portion 22 and extends around the entire circumference of the core back portion 22. The outer circumference portion 22a and the inner circumference portion 22b are each formed in an annular shape. The outer circumference portion 22a and the inner circumference portion 22b are arranged coaxially with a radial offset between them.
The outer periphery 22a of adjacent electrical steel sheets 40 in the stacking direction is bonded to each other by the adhesive portion 3a. On the other hand, the inner periphery 22b of adjacent electrical steel sheets 40 in the stacking direction is not bonded to each other by the adhesive portion 3a. A masking agent (not shown) may be placed on the surface of the inner periphery 22b of the core back portion 22.
In other words, the surface of the electrical steel sheet 40 facing the lamination direction (hereinafter referred to as the first surface) has a mixture of regions that are bonded to each other by adhesive portions 3a (hereinafter referred to as bonded regions) and regions that are not bonded to each other by adhesive portions 3a (hereinafter referred to as non-bonded regions).

The method for identifying the adhesive and non-adhered areas between two electromagnetic steel sheets 40 is as follows: Specifically, the electromagnetic steel sheets 40 that are bonded together via the adhesive portion 3a are separated. The first surface of the separated electromagnetic steel sheets 40 is then observed. Areas where adhesive residue of the insulating coating 3 remains after the delamination of the adhesive area are determined to be the adhesive area, and areas where no adhesive residue remains are determined to be the non-adhered area (as mentioned above, no adhesive residue remains in areas that are fixed by tackiness). Image processing using a computer or artificial intelligence may be used for this determination.

In this embodiment, the multiple electromagnetic steel sheets forming the rotor core 31 have through holes 42 and 43 as shown in Figure 1. These multiple electromagnetic steel sheets are fixed to each other by crimping (dowels) not shown. However, the multiple electromagnetic steel sheets forming the rotor core 31 may also have a laminated structure fixed by an insulating coating 3, similar to the stator core 21.
Furthermore, laminated cores such as the stator core 21 and rotor core 31 may be formed by a so-called spiral stacking method.

(Method for manufacturing the stator core 21)
Next, we will explain the method for manufacturing the stator core 21 configured as described above (hereinafter also simply referred to as the manufacturing method).
Figure 7 shows a side view of a manufacturing apparatus 100 that is preferably used in this manufacturing method.
In the manufacturing apparatus 100, the material 1 is fed from the coil 1A (hoop) in the direction of arrow F, and multiple punching operations are performed by dies positioned at each stage to gradually form the shape of the electromagnetic steel sheet 40. For example, a masking agent is applied to the electromagnetic steel sheet 40 while it is being formed.
Next, multiple punched electrical steel sheets 40 are stacked. The stacked electrical steel sheets 40 are heated and pressurized. As a result, adjacent electrical steel sheets 40 in the stacking direction are bonded (fused) together by the adhesive portion 3a to which the insulating coating 3 is fused.

As shown in Figure 7, the manufacturing apparatus 100 is equipped with multiple punching stations 110. The punching stations 110 may have two stages, or three or more stages. Each punching station 110 is equipped with a female die 111 positioned below the material 1 and a male die 112 positioned above the material 1.
Among the multiple stages of female molds 111, the coating section 130 is positioned between adjacent female molds 111 in the direction of arrow F (the direction in which the material 1 is fed). The coating section 130 is composed of multiple supply pipes 131.

The manufacturing apparatus 100 further includes a stacking station 140 located downstream of the furthest downstream punching station 110. This stacking station 140 includes a heating device 141, an outer peripheral punching female die (mold) 142, a heat insulating member 143, an outer peripheral punching male die 144, and a spring 145.
The heating device 141, the outer periphery female die 142, and the heat insulating member 143 are located below the material 1. In this example, the heating device 141 is located in the outer periphery female die 142. On the other hand, the outer periphery male die 144 and the spring 145 are located above the material 1. Reference numeral 21 indicates the stator core.

The manufacturing method of this embodiment is carried out using the manufacturing apparatus 100 having the configuration described above. Figure 8 is a flowchart of the manufacturing method S.
First, material 1 is sequentially fed from coil 1A in the direction of arrow F in Figure 7. Then, a punching and coating process (step S1 shown in Figure 8) is performed on this material 1.
In the punching and coating process S1, the punching process S2 and the coating process S3 are performed.
In punching process S2, punching is performed using a multi-stage punching station 110. By performing punching process S2, the material 1 is given the shape of an electromagnetic steel sheet 40 having a core back portion 22 and multiple teeth portions 23 as shown in Figure 3. However, since it is not completely punched out at this point, the process proceeds to the next step along the direction of arrow F.

In coating step S3, as shown in Figure 9, the masking agent 65 is applied to the central portion 23c of the teeth portion 23 and the inner circumference 22b of the core back portion 22 of the electrical steel sheet 40 by multiple supply pipes 131 of the coating unit 130.
As shown in Figure 7, the material 1 is sent to the lamination station 140, where it is punched out by the outer peripheral punching die 144, and an electrical steel sheet 40 is manufactured from the material 1. The punching process S2 is completed with the above steps. In this embodiment, the coating process S3 is performed during the punching process S2. However, the coating process S3 may be performed before the punching process S2, or after the punching process S2.
Once the punching and coating process S1 is completed, the process proceeds to step S6.

Next, in the lamination process (step S6), the electromagnetic steel sheets 40 are dropped downward from the material 1, and multiple electromagnetic steel sheets 40 are laminated in the outer peripheral punching die 142. The multiple electromagnetic steel sheets 40 are laminated so that the surfaces coated with the masking agent 65 face the same direction. The multiple electromagnetic steel sheets 40 are laminated with precision in the outer peripheral punching die 142. In the lamination process S6, the electromagnetic steel sheets 40 are subjected to a constant pressure by the spring 145.
By performing the punching and coating process S1 and the lamination process S6 described above for a certain period of time, a predetermined number of electromagnetic steel sheets 40 can be stacked within the outer peripheral punching female die 142.
Once the lamination process S6 is completed, the process proceeds to step S11.

Next, in the bonding process (step S11), the insulating coating 3 is made to adhere to adjacent electrical steel sheets 40 in the lamination direction. Specifically, the heating device 141 heats the multiple electrical steel sheets 40 to, for example, a temperature of 200°C. This melts the insulating coating 3 on the electrical steel sheets 40. When the melted portion cools, this portion hardens to form an adhesive portion 3a, and the portions of the surface of the electrical steel sheets 40 that have not been coated with the masking agent 65 are bonded together. Specifically, in the bonding process S11, the tip portion 23a and both side ends 23b of the teeth portion 23 and the outer peripheral portion 22a of the core back portion 22 of adjacent electrical steel sheets 40 in the lamination direction are bonded to each other by the adhesive portion 3a.
Thus, in the portion of the electromagnetic steel sheet 40 to which the masking agent 65 is applied, the adhesive properties of the insulating film 3 are not exhibited even if the insulating film 3 is heated. On the other hand, in the portion of the electromagnetic steel sheet 40 to which the masking agent 65 is not applied, if the insulating film 3 is heated or otherwise exhibited, the insulating film 3 will adhere to adjacent electromagnetic steel sheets 40 in the lamination direction by the insulating film 3.

In bonding step S11, the adhesive properties of the insulating film 3 are activated while the masking agent 65 is applied, so that the central portion 23c of the teeth portion 23 and the inner circumference 22b of the core back portion 22 of adjacent electrical steel sheets 40 in the lamination direction are not bonded to each other by the insulating film 3.
Once the bonding process S11 is completed, all steps of the manufacturing method S are finished, and the stator core 21 is manufactured.
The manufacturing apparatus 100 does not necessarily have to include a heating device 141 and a heat insulating member 143. In this case, the heating device may be placed separately from the manufacturing apparatus 100, for example, for a process downstream of the manufacturing apparatus 100.
If the manufacturing apparatus 100 does not have a heating device 141, the multiple electromagnetic steel sheets 40 will not be bonded to each other in the outer peripheral punching die 142. Before bonding the electromagnetic steel sheets 40 stacked in the outer peripheral punching die 142, the multiple electromagnetic steel sheets 40 are removed from the outer peripheral punching die 142. In this case, the multiple electromagnetic steel sheets 40 stacked in the outer peripheral punching die 142 may be held by being sandwiched from both sides in the stacking direction with a jig (not shown) before being transported or heated.

The rotating electric machine 10, configured as described above, is then operated. At this time, as shown in Figure 10, the magnetic flux lines L generated by the rotating electric machine 10 have less difficulty passing through the outer circumference 22a of the electromagnetic steel sheet 40 compared to the inner circumference 22b. Note that in Figure 10, the adhesive portion 3a is not shown, and the boundaries between the outer circumference 22a and inner circumference 22b of the core back portion 22, and the boundaries between the tip portion 23a, side end portion 23b, and central portion 23c of the teeth portion 23 are shown by dashed lines.

As described above, according to the stator core 21 of this embodiment, a rotating electric machine 10 is constructed using the stator core 21, and this rotating electric machine 10 is operated. Generally, the magnetic flux lines L generated in the rotating electric machine 10 at this time have difficulty passing through the outer circumference 22a of the electromagnetic steel sheet 40 compared to the inner circumference 22b. Therefore, even if the outer circumference 22a of adjacent core back portions 22 in the stacking direction are bonded to each other by an insulating coating 3, the application of compressive stress to the inner circumference 22b, through which the magnetic flux lines L can easily pass, is suppressed, thereby reducing the influence on the magnetic flux lines L and preventing a decrease in the magnetic properties of the stator core 21.
Furthermore, the tip portion 23a and both end portions 23b of the teeth portion 23 of adjacent electrical steel sheets 40 in the stacking direction are bonded to each other by the insulating coating 3. This prevents the tip portion 23a and both end portions 23b of one tooth portion 23 from lifting away from the tip portion 23a and both end portions 23b of the other tooth portion 23 of adjacent electrical steel sheets 40 in the stacking direction. This makes it possible to more reliably suppress the deterioration of the magnetic properties of the stator core 21. In addition, the central portions 23c of the teeth portion 23 of adjacent electrical steel sheets 40 in the stacking direction are not bonded to each other by the insulating coating 3. This makes it possible to suppress the deterioration of the magnetic properties of the stator core 21 by applying compressive stress to this portion.

In the stator core 21, the first circumference of the core back portion 22 is the outer circumference 22a of the core back portion 22. This suppresses the deterioration of the magnetic properties of the stator core 21 when the stator core 21 is an inner rotor type.

Furthermore, the adhesive portions of adjacent electrical steel sheets 40 in the lamination direction are bonded together by the insulating coating 3. That is, there is no substance with a different composition from the insulating coating 3 (for example, an adhesive applied during the core manufacturing process) at the boundary between adjacent electrical steel sheets 40 in the lamination direction, and the insulating coating 3 covering the surface of each adjacent electrical steel sheet 40 is integrated and homogeneous. As a result, compared to conventional stator cores where an adhesive, a substance different from the insulating coating 3, is applied to form partial adhesive portions, the generation of compressive stress associated with localized bonding is suppressed, and the deterioration of the magnetic properties of the stator core 21 can be suppressed.

Furthermore, in a stator core 21 where localized bonding areas are formed between adjacent electromagnetic steel sheets 40 in the lamination direction by localized heating and/or pressurization, the non-bonded areas are in a state of strong contact between adjacent electromagnetic steel sheets 40 in the lamination direction. Therefore, when the stator core 21 is assembled to the rotating electric machine 10 and operates, unintended vibrations in the non-bonded areas are suppressed, stabilizing the rotation of the rotor 30 and preventing a decrease in the overall magnetic properties of the rotating electric machine 10.

Furthermore, according to the manufacturing method S of this embodiment, multiple electromagnetic steel sheets 40 to which the masking agent 65 has been applied in the coating step S3 are laminated in the lamination step S6. Then, even if the outer peripheral portions 22a of adjacent core back portions 22 in the lamination direction are bonded to each other by the insulating coating 3 in the bonding step S11, the application of compressive stress to the inner peripheral portion 22b through which magnetic flux lines L can easily pass is suppressed, thereby reducing the influence on magnetic flux lines L and preventing a decrease in the magnetic properties of the stator core 21.
Furthermore, in the bonding process S11, the tip 23a and both end portions 23b of the teeth 23 of adjacent electrical steel sheets 40 in the lamination direction are bonded to each other by the insulating coating 3. This prevents the tip 23a and both end portions 23b of one tooth 23 from lifting away from the tip 23a and both end portions 23b of the other tooth 23 of adjacent electrical steel sheets 40 in the lamination direction. This suppresses a decrease in the magnetic properties of the stator core 21.
In manufacturing method S, the first circumference of the core back portion 22 is the outer circumference 22a of the core back portion 22. This makes it possible to suppress a decrease in the magnetic properties of the stator core 21 when the stator core 21 is of the inner rotor type.

In a stator core 21 manufactured by method S, which involves applying a masking agent 65 to form non-adherent areas between adjacent electromagnetic steel sheets 40 in the lamination direction, these non-adherent areas are in a state of strong contact between adjacent electromagnetic steel sheets 40 in the lamination direction. Therefore, when the stator core 21 is assembled to the rotating electric machine 10 and operates, unintended vibrations of the non-adherent areas are suppressed, stabilizing the rotation of the rotor 30 and preventing a decrease in the overall magnetic properties of the rotating electric machine 10.

The manufacturing apparatus 100 of this embodiment can be modified in various ways, as will be described below.
In the manufacturing apparatus 100, the coating section 130 may be provided on the outer peripheral punching female die 142. In this case, for example, the coating process is performed between the lamination process. In the coating process, the masking agent 65 is applied inside the outer peripheral punching female die 142.
By configuring the manufacturing apparatus as shown in this modified example, it is possible to prevent misalignment in the position where the masking agent 65 is applied to the electromagnetic steel sheet 40 when punching out the electromagnetic steel sheet 40 from the material 1 using the outer peripheral punching female die 142.
Furthermore, the mold used to apply the masking agent 65 internally is not limited to the outer perimeter punching female mold 142.

As shown in the manufacturing apparatus 100A in Figure 11, the multiple supply pipes 131 of the coating section 130 may be arranged between adjacent male molds 112 in the direction of arrow F among the multiple stages of male molds 112.
As shown in Figure 12, the manufacturing apparatus 100 may be equipped with a coating section 130B instead of the coating section 130. In the supply pipe 132 provided by the coating section 130B, multiple branch pipes 134 branch off from the main pipe 133. In this modified example, during the coating process, a masking agent 65 is applied to the electrical steel sheet 40 from the multiple branch pipes 134.

As shown in Figure 13, the manufacturing apparatus 100 of this embodiment may be equipped with a coating section 130C instead of the coating section 130. The coating section 130C comprises a plurality of (two in this modified example) rolls 136 and a supply section (not shown). The coating section 130C is positioned between adjacent punching stations 110 in the direction of arrow F among a plurality of punching stations 110. The plurality of rolls 136 sandwich the material 1 in the thickness direction of the material 1. The plurality of rolls 136 feed the material 1 in the direction of arrow F while rotating around the axis of each roll 136.
The supply unit supplies the masking agent 65 to the surface of at least one of the multiple rolls 136.
In the manufacturing method using this manufacturing apparatus 100C, the masking agent 65 is applied using multiple rolls 136 during the coating process.
According to this modified manufacturing method, the masking agent 65 can be accurately applied to each position of the electrical steel sheet 40 using multiple rolls 136.
In this modified example, the coating section may be provided with a single roll 136.

The manufacturing apparatuses 100A to 100C described above can also be preferably used in the manufacturing method S of this embodiment, similar to manufacturing apparatus 100.

In this embodiment, the ends 23b of the teeth 23 of adjacent electrical steel sheets 40 in the lamination direction do not need to be bonded to each other by the adhesive portion 3a. In this case, in the manufacturing method, in the coating step, a masking agent 65 is applied to the central portion 23c and both ends 23b of the teeth 23 of the electrical steel sheet 40. In the bonding step, the central portion 23c and both ends 23b of the teeth 23 of adjacent electrical steel sheets 40 in the lamination direction (at least the portions of the teeth 23 other than the tip portion 23a and both ends 23b) are not bonded to each other by the adhesive portion 3a.
In this modified stator core, the tip portions 23a of the teeth portions 23 of adjacent electromagnetic steel sheets 40 in the stacking direction are bonded to each other by the insulating coating 3. This prevents the tip portion 23a of one tooth portion 23 from lifting away from the tip portion 23a of the other tooth portion 23 of adjacent electromagnetic steel sheets 40 in the stacking direction. This suppresses a decrease in the magnetic properties of the stator core.
Furthermore, in this modified manufacturing method, the tip portions 23a of the teeth portions 23 of adjacent electromagnetic steel sheets 40 in the lamination direction are bonded to each other by the insulating coating 3 during the bonding process. This prevents the tip portion 23a of one tooth portion 23 from lifting away from the tip portion 23a of the other tooth portion 23 of adjacent electromagnetic steel sheets 40 in the lamination direction. This suppresses a decrease in the magnetic properties of the stator core 21.

Here, as shown in Figure 3, the width of the teeth portion 23 (main body portion 25) is M1. The width of each side end portion 23b is M2/2. In this case, the sum of the widths of both side end portions 23b formed on each teeth portion 23 is M2. The radial length of the core back portion 22 is M3. The radial length of the outer circumference portion 22a is M4.
In this case, the value of (M2/M1) is preferably 0.1 or more and 0.5 or less. When the value of (M2/M1) is within this range, the application of compressive stress to the widthwise central portion of the teeth portion 23, which is the part where the magnetic flux lines L are concentrated in the teeth portion 23, is suppressed. Therefore, the deterioration of the magnetic properties of the stator core 21 can be suppressed more reliably.
On the other hand, if the value of (M2/M1) is between 0 and 0.1, the decrease in magnetic properties is suppressed in the central part 23c of the teeth portion 23. However, in this case, there is a risk that the magnetic properties of the stator core 21 will decrease in the central part 23c due to the teeth portion 23 lifting up.
Furthermore, if the value of (M2/M1) is greater than 0.5, the range of the central part 23c becomes smaller, which may cause a decrease in the magnetic properties of the stator core 21.

The (M4/M3) value is most preferably between 0.1 and 0.3. When the (M4/M3) value is within this range, compressive stress is suppressed in the inner circumference 22b, which is the part of the core back portion 22 where magnetic flux lines L are concentrated. Therefore, the deterioration of the magnetic properties of the stator core 21 can be suppressed more reliably.
On the other hand, it is preferable that the value of (M4/M3) is greater than 0.3 and less than or equal to 0.5. When the value of (M4/M3) is within this range, the application of compressive stress to the inner circumference 22b of the core back portion 22 is suppressed. Therefore, it is possible to suppress the deterioration of the magnetic properties of the stator core 21.
Furthermore, if the value of (M4/M3) is greater than 0.5 and less than or equal to 0.8, the application of compressive stress to the inner circumference 22b of the core back portion 22 is suppressed, and the deterioration of the magnetic properties of the stator core 21 is somewhat suppressed.
If the value of (M4/M3) is greater than 0.8, the magnetic flux lines L in the core back portion 22 will be bonded to the area where they are concentrated, which may cause a decrease in the magnetic properties of the stator core 21.

Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and modifications, combinations, deletions, etc., of the configuration are also included without departing from the spirit of the present invention.
For example, in the above embodiment, the multiple teeth portions 23 may protrude radially outward from the outer circumference of the core back portion 22. In this case, the first circumference of the core back portion 22 corresponds to the inner circumference 22b of the core back portion 22. The second circumference of the core back portion 22 corresponds to the outer circumference 22a of the core back portion 22.
In other words, the first circumference is either the outer circumference 22a or the inner circumference 22b of the core back portion 22. The second circumference is the portion of the core back portion 22 other than the first circumference.

The shape of the stator core 21 is not limited to the form shown in the above embodiment. Specifically, the outer and inner diameters of the stator core 21, the stacking thickness, the number of slots, the circumferential and radial dimensional ratio of the teeth portion 23, and the radial dimensional ratio between the teeth portion 23 and the core back portion 22 can be arbitrarily designed according to the desired characteristics of the rotating electric machine.
In the rotor 30 of the above embodiment, one permanent magnet 32 forms one magnetic pole, but the present invention is not limited to this form. For example, two permanent magnets 32 may form one magnetic pole as a pair, or three or more permanent magnets 32 may form one magnetic pole as a pair.

In the above embodiment, a permanent magnet field type electric motor was described as an example of a rotating electric machine 10. However, the structure of the rotating electric machine 10 is not limited to this, as illustrated below, and various other known structures not illustrated below can also be used.
In the above embodiment, a permanent magnet field type motor was described as an example of a rotating electric machine 10, but the present invention is not limited to this. For example, the rotating electric machine 10 may be a reluctance type motor or an electromagnet field type motor (wound field type motor).
In the above embodiment, a synchronous motor was used as an example of an AC motor, but the present invention is not limited thereto. For example, the rotating electric machine 10 may be an induction motor.
In the above embodiment, an AC motor was used as an example of the rotating electric machine 10, but the present invention is not limited thereto. For example, the rotating electric machine 10 may be a DC motor.
In the above embodiment, an electric motor was used as an example of the rotating electric machine 10, but the present invention is not limited thereto. For example, the rotating electric machine 10 may be a generator.

2. Base steel plate 3. Insulating coating 21. Stator core (laminated core)
22 Core back section 22a Outer circumference section (first circumference section)
22b Inner peripheral part (second peripheral part)
23 Teeth section 23a Tip section 23b Side end section 31 Rotor core (laminated core)
40 Electrical steel sheet 65 Masking agent 136 Roll 142 Outer edge punching female die (die)
S Manufacturing method (Method for manufacturing laminated cores)
S3 Coating process S6 Laminating process S11 Adhesive process

Claims (7)

A laminated core in which multiple electromagnetic steel sheets, each coated with an insulating film having adhesive properties, are stacked in the stacking direction,
The electrical steel sheet comprises a core back portion and a teeth portion projecting radially from the core back portion.
The radial tip portions of the teeth portions of adjacent electrical steel sheets in the lamination direction, and the first circumferential portion of the core back portion, which is the portion opposite to the teeth portion in the radial direction, are bonded to each other by the insulating coating.
In the core back portion of the electrical steel sheets adjacent to each other in the lamination direction, a part of the second circumferential portion other than the first circumferential portion is located at the same distance from the central axis of the core back portion, and the entire circumferential portion extending around the entire circumference of the core back portion is not bonded to each other by the insulating coating.
The circumferential ends of the teeth portions of adjacent electrical steel sheets in the stacking direction are bonded to each other by the insulating coating.
A laminated core in which the teeth portions of adjacent electrical steel sheets in the lamination direction, other than the tip and both side ends, are not bonded to each other by the insulating coating . The laminated core according to claim 1 , wherein the first peripheral portion of the core back portion is the outer peripheral portion of the core back portion. A method for manufacturing a laminated core, wherein a plurality of electromagnetic steel sheets coated with an insulating film having adhesive properties are stacked in the stacking direction,
The electrical steel sheet comprises a core back portion and a teeth portion projecting radially from the core back portion.
A coating step of applying a masking agent to at least the portion of the teeth portion of the electromagnetic steel sheet other than the radial tip portion and both circumferential ends, and to a portion of the second circumferential portion of the core back portion, which is the portion on the teeth portion side in the radial direction, and which is arranged at the same distance from the central axis of the core back portion and covers the entire circumference of the core back portion .
A lamination process for stacking the aforementioned plurality of electrical steel sheets,
A bonding step in which the insulating coating exerts its adhesive properties on adjacent electrical steel sheets in the lamination direction, thereby bonding the tip portions of the teeth portions and the first peripheral portions of the core back portion, excluding the second peripheral portion, of adjacent electrical steel sheets in the lamination direction to each other with the insulating coating,
Perform
A method for manufacturing laminated cores in which, in the bonding step, at least the portions of the teeth other than the radial tip and both circumferential ends, and the entire circumference of the core back portion, of the electrical steel sheets adjacent to each other in the lamination direction, are not bonded to each other by the insulating coating. In the coating step, the masking agent is applied to the portion of the tooth portion of the electrical steel sheet other than the radial tip and the circumferential ends.
In the bonding process,
By allowing the insulating coating to exhibit its adhesive properties to adjacent electrical steel sheets in the stacking direction, the circumferential ends of the teeth portions of adjacent electrical steel sheets in the stacking direction are bonded to each other by the insulating coating.
The method for manufacturing a laminated core according to claim 3 , wherein the portions of the teeth of adjacent electrical steel sheets in the lamination direction, other than the tip and both side ends, are not bonded to each other by the insulating coating. The method for manufacturing a laminated core according to claim 3 or 4 , wherein the masking agent is applied by a roll in the coating step. The method for manufacturing a laminated core according to claim 3 or 4 , wherein the masking agent is applied in the mold during the coating step. The method for manufacturing a laminated core according to any one of claims 3 to 6 , wherein the first peripheral portion of the core back portion is the outer peripheral portion of the core back portion.