EA040618B1 - GLUE-SLATED CORE FOR STATOR AND ELECTRIC MOTOR - Google Patents

Description

Technical field

The present invention relates to a glued laminated core for a stator and an electric motor. Priority is claimed from Japanese Patent Application No. 2018-235865 filed in Japan on December 17, 2018, the contents of which are hereby incorporated by reference.

Background of the invention

Conventionally, the laminated core described in the following Patent Document 1 has been known. In the following Patent Document 1, the problem is to improve the heat conduction characteristics in the stacking direction while securing the adhesive strength and electrical insulation properties between electrical steel sheets. In order to solve this problem, a laminated core formed by laminating electrical steel sheets each having an insulating coating on its surface and having a configuration in which at least an organic substance layer formed from an adhesive is present between the electrical steel sheets. organic matter, and the average thickness of the organic matter layers is 4 µm or less. The sticky organic substance has a viscosity of 1.0 Pa-s or less at a temperature at which fluidity is required before the curing reaction. In addition, a layer of organic matter is introduced between electrical steel sheets using a vacuum impregnation method.

Bibliography

Patent Documents.

Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 200488970.

The essence of the invention

Problems solved by the invention.

The electrical steel sheet and the adhesive organic substance (hereinafter referred to as the adhesive part) have different thermal expansion coefficients from each other. Therefore, when the electrical steel sheets are simply glued together and heated to cure the adhesive portion, as in Patent Document 1, the adhesive portion undergoes thermal shrinkage, and a compressive or tensile stress is applied to the electrical steel sheets at. When these voltages are applied to electrical steel sheets, there is a possibility that the magnetic properties of the laminated core deteriorate. The possibility of deterioration of the magnetic properties increases as the electrical steel sheets become thinner and the adhesive part becomes thicker. On the other hand, even in the case of a room temperature curing adhesive, shrinkage occurs during curing. Therefore, with any adhesive of the thermoset or room temperature type, there is a possibility that curing shrinkage will cause deterioration of the magnetic properties.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bonded-laminated stator core in which deterioration of magnetic property due to curing shrinkage of an adhesive can be suppressed, as well as a motor including such a bonded-laminated core for a stator. laminated core for the stator.

Means of solving the problem.

In order to solve the above problems, the present invention uses the following means.

(1) A glued-laminated stator core according to one aspect of the present invention includes a plurality of laminated electrical steel sheets each coated on both sides with an insulating coating, and an adhesive portion disposed at a plurality of points between each of the electrical steel sheets adjacent to each other in the laying direction, and made to cause adhesion of electrical steel sheets to each other, and the chemical composition of each of the electrical steel sheets includes from 2.5 to 3.9% by mass of Si, the average tensile modulus of each of the adhesive portions is 2500 to 5000 MPa, and when the average thickness of each of the electrical steel sheets is t1 in mm, the average thickness of each of the adhesive portions is t2 in µm, and the average yield strength of each of the electrical steel sheets is YP in MPa, either condition A of compliance with the following expressions is satisfied conditions 1, 2 and 3, or condition B of compliance with the following expressions 3, 4 and 5, or a combination of them:

50xt1-12<t2<50xt1-6 (expression 1),

0.15<t1<0.27 (expression 2),

0.5<t2<2.5 (expression 3),

0.025xYP-12<t2<0.025xYP-8 (expression 4),

380<YP<540 (expression 5).

Here, as the material constituting the insulating coating, for example, (1) an inorganic compound, (2) an organic resin, (3) a mixture of an inorganic compound, and

- 1 040618 organic resin, etc. Of these, (1) an inorganic compound or (3) a mixture of an inorganic compound and an organic resin as an insulating coating can largely suppress deterioration in magnetic property due to curing shrinkage of an adhesive.

(2) The following configuration can be used in the above paragraph (1). Only condition A is satisfied, or both conditions A and B are satisfied, wherein the average sheet thickness tl is in the range of 0.20 to 0.25 mm and the average thickness t2 is in the range of 1.0 to 2.0 µm.

(3) The following configuration can be used in the above paragraph (1). Only condition B is satisfied, or both conditions A and B are satisfied, wherein the average thickness t2 is in the range of 1.0 to 2.0 µm and the average yield point YP is in the range of 450 to 500 MPa.

(4) In any of (1) to (3) above, each of the adhesive portions may contain an acrylic-based oil-based surface adhesive or an epoxy-based oil-based surface adhesive, or a combination thereof as an oil component.

(5) In any of (1) to (3) above, each of the adhesive portions may be a room temperature-curing acrylic-based adhesive containing a second-generation acrylic adhesive (SGA) comprising an elastomer-containing acrylic-based adhesive.

(6) An electric motor according to one aspect of the present invention includes a bonded core for a stator according to any one of (1) to (5) above.

effects of the invention.

According to the above-described aspects of the present invention, there can be provided an adhesive laminated stator core in which magnetic deterioration due to curing shrinkage of an adhesive can be suppressed, as well as a motor including such an adhesive laminated stator core.

Brief description of the drawings

Fig. 1 is a sectional view of an electric motor including a bonded-laminated core for a stator in accordance with one embodiment of the present invention.

Fig. 2 is a side view of a glued laminated core for a stator.

Fig. 3 is a sectional view along line A-A in FIG. 2 illustrating an example of a drawing of the formation of an adhesive portion in a glued-laminated core for a stator.

Fig. 4 is a side view of a manufacturing apparatus used to produce one example of a bonded-laminated stator core.

Fig. 5 is a graph showing the relationship between the average thickness t1 of the electrical steel sheets and the average thickness t2 of the adhesive parts in the same example.

Fig. 6 is a graph showing the relationship between the average value YP of the yield strengths of electrical steel sheets and the average thickness t2 of the adhesive portions in the same example.

Embodiments of the invention

Next, with reference to the attached drawings, a glued-laminated stator core according to one embodiment of the present invention will be described, as well as an electric motor including this glued-laminated stator core. In the present embodiment, as one example of a motor, a motor, more specifically an AC motor, more specifically a synchronous motor, and still more specifically a constant magnetic field motor, will be described. This type of engine is suitably used in electric vehicles (EVs), for example.

As illustrated in FIG. 1, the motor 10 includes a stator 20, a rotor 30, a housing 50, and a rotating shaft 60. The stator 20 and the rotor 30 are enclosed in a housing 50. The stator 20 is fixed in the housing 50. In the present embodiment, an internal rotor motor is used as the motor 10. , in which the rotor 30 is disposed radially inward of the stator 20. However, as the motor 10, an external rotor motor in which the rotor 30 is disposed on the outer side of the stator 20 can also be used. In addition, in the present embodiment, the motor 10 is 12-pole, 18-slot, three-phase AC motor. However, the number of poles, the number of slots, the number of phases or the like can be changed accordingly. The electric motor 10 may be rotated at a rotation speed of 1000 rpm while applying to each phase, for example, a drive current having an effective value of 10 A and a frequency of 100 Hz.

The stator 20 includes a glued-laminated stator core 21 (hereinafter referred to as the stator core) and a winding (not shown). The stator core 21 includes an annular back portion 22 and a plurality of toothed portions 23. Hereinafter, the direction of the central axis O of the stator core 21 (or back portion 22) is referred to as the axial direction, the radial direction (direction perpendicular to the central axis O) of the core 21 the stator core (or core back portion 22) is referred to as the radial direction, and the circumferential direction (rotational direction about the central axis O) of the stator core 21 (or core back portion 22) is referred to as the circumferential direction.

- 2 040618

The back portion 22 of the core is formed with an annular shape in a plan view of the stator 20 in the axial direction. A plurality of toothed portions 23 protrude inwardly in the radial direction (towards the central axis O of the core back portion 22 in the radial direction) from the inner circumferential periphery of the core back portion 22. A plurality of toothed portions 23 are arranged at equal angle intervals in the circumferential direction. In the present embodiment, 18 tooth portions 23 are provided every 20° in terms of a central angle with the central axis O as the center. The plurality of toothed portions 23 are made to have the same shape and the same size. Therefore, the plurality of toothed portions 23 have the same thickness dimension with each other. The winding is wound around the gear portions 23. The winding may be a concentrated winding or a distributed winding.

The rotor 30 is located on the radially inner side with respect to the stator 20 (stator core 21). The rotor 30 includes a rotor core 31 and a plurality of permanent magnets 32. The rotor core 31 is in the form of a ring (annular shape) located coaxially with the stator 20. A rotating shaft 60 is located in the rotor core 31. The rotating shaft 60 is attached to the core 31 of the rotor. A plurality of permanent magnets 32 are attached to the rotor core 31. In the present embodiment, a set of two permanent magnets 32 forms one magnetic pole. A plurality of sets of permanent magnets 32 are arranged at equal angle intervals in the circumferential direction. In the present embodiment, 12 sets of permanent magnets 32 (a total of 24 magnets) are provided every 30° in terms of a central angle with the central axis O as the center.

In the present embodiment, a motor with built-in permanent magnets is used as the permanent magnetic motor. The rotor core 31 is provided with a plurality of through holes 33 penetrating 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 of the permanent magnets 32 is attached to the rotor core 31 in a position inside the respective through hole 33. The attachment of each permanent magnet 32 to the rotor core 31 can be realized, for example, by gluing the outer surface the permanent magnet 32 and the inner surface of the through hole 33 with each other using an adhesive. In addition, as a permanent magnetic motor, a surface permanent magnet motor can be used instead of an internal magnet motor.

The stator core 21 and the rotor core 31 are both laminated cores. As illustrated in FIG. 2, the stator core 21 may be formed, for example, by laminating a plurality of electrical steel sheets 40 in the stacking direction. Each thickness of the laminated stack (the entire length along the central axis O) of each of the stator core 21 and the rotor core 31 may be, for example, 50.0 mm. The outer diameter of the stator core 21 may be 250.0 mm, for example. The inner diameter of the stator core 21 may be 165.0 mm, for example. The outer diameter of the rotor core 31 may be 163.0 mm, for example. The inner diameter of the rotor core 31 may be 30.0 mm, for example. However, these values are exemplary, and the thickness of the laminated package, the outer diameter and inner diameter of the stator core 21, and the thickness of the laminated package, the outer diameter and the inner diameter of the rotor core 31 are not limited to these values. Here, the far edge of the tooth portion 23 of the stator core 21 is used to determine the inner diameter of the stator core 21. Those. the inner diameter of the stator core 21 is the diameter of a virtual circle inscribed in the far edges of all the gear portions 23.

Each of the electrical steel sheets 40 constituting the stator core 21 and the rotor core 31 can be formed, for example, by punching the electrical steel sheet as the base material or the like. As the electrical steel sheet 40, a known electrical steel sheet may be used. The chemical composition of the electrical steel sheet 40 includes 2.5 to 3.9% Si by mass%, as illustrated below. Content ranges of chemical composition components other than Si are not specifically limited, but satisfactory ranges in the present embodiment are described below. When the chemical composition is within these ranges, the YP average value of the yield strengths of each electrical steel sheet 40 may be set to 380 MPa or more and 540 MPa or less.

Si: 2.5-3.9%,

Al: 0.001-3.0%,

Mn: 0.05-5.0%, the rest: iron and impurities.

In the present embodiment, as the electrical steel sheet 40, an isotropic electrical steel sheet is used. As the isotropic electrical steel sheet, JIS C 2552:2014 isotropic electrical steel strip can be used. However, as the electrical steel sheet 40, it is also possible to use the anisotropic electrical steel sheet instead of the isotropic electrical steel sheet. as sheet

- 3 040618 anisotropic electrical steel in this case, an anisotropic electrical steel strip according to JIS C 2553:2012 can be used.

In order to improve the workability of the electrical steel sheet 40 and the magnetic loss of the stator core 21 (which may be referred to simply as the laminated core hereinafter), both sides of the electrical steel sheet 40 are coated with an insulating coating. As the material constituting the insulating coating, for example, (1) an inorganic compound, (2) an organic resin, (3) a mixture of an inorganic compound and an organic resin, and the like can be used. Of these, (1) an inorganic compound or (3) a mixture of an inorganic compound and an organic resin as an insulating coating can largely suppress the deterioration of magnetic properties due to shrinkage of each adhesive portion upon curing. As an example of an inorganic compound, for example, (1) a dichromate-boric acid compound, and (2) a phosphate-silica compound, or the like can be given. As an example of the organic resin, epoxy resin, acrylic resin, acrylic styrene resin, polyester resin, silicone resin, fluororubber or the like can be mentioned.

In order to ensure insulation performance between the electrical steel sheets 40 laminated to each other, the value of the upper limit of the average thickness of the insulating coating (average thickness per side of the electrical steel sheet 40) can be set to 1.5 µm, and more preferably 1, 2 µm. On the other hand, as the thickness of the insulating coating increases, the insulating effect saturates. In addition, as the thickness of the insulating coating increases, the proportion occupied by the electrical steel sheet 40 in the laminated core decreases, and the performance of the laminated core deteriorates. Therefore, the insulating coating is preferably made thin in the range in which the insulation performance can be secured. The lower limit value of the average thickness of the insulating coating (thickness per side of the electrical steel sheet 40) can be set to 0.3 µm, and more preferably 0.5 µm. As an average thickness of the insulating coating, for example, 0.8 µm within the above-described range of the lower and upper limits can be used.

The average thickness of the insulating coating is the average of the entire laminated core. The thickness of the insulating coating is made such that it practically does not change in all positions of the lamination in the laying direction and circumferential positions around the central axis of the laminated core. Therefore, the average thickness of the insulating coating can be set equal to the numerical value measured at the position of the upper end of the laminated core. In addition, instead of the electrical steel sheet 40 with an insulating coating, an electrical steel sheet on which no insulating coating is formed can be used.

When other factors affecting the magnetic properties of the electrical steel sheet 40, such as curing shrinkage of the adhesive portion 41 to be described below, are also considered, it is preferable to use 0.15 mm or more and 0.27 mm or less as the average thickness t1 of each electrical steel sheet 40, but the present invention is effective even when the average thickness t1 is outside this range. When the average thickness t1 of the electrical steel sheets 40 is reduced to less than 0.15 mm, compressive stress and tensile stress may occur in each electrical steel sheet 40 due to curing shrinkage of the adhesive portion 41, and as a result, there is a possibility that the magnetic properties of each electrical steel sheet 40 deteriorate. On the other hand, when the average thickness t1 of the electrical steel sheets 40 exceeds 0.27 mm, the absolute value of the magnetic loss increases and the magnetic property effects cannot be obtained. In addition, the thickness of the electrical steel sheet 40 includes the thickness of the insulating coating. The average thickness t1 of the electrical steel sheets 40 is the average of the entire laminated core. The thickness of each electrical steel sheet 40 is made to be substantially unchanged at all laminating positions in the laying direction and circumferential positions around the central axis of the laminating core. Therefore, the average thickness t1 of the electrical steel sheets 40 can be set to a numerical value measured at the position of the upper end of the laminated core.

As illustrated in FIG. 3, a plurality of electrical steel sheets 40 constituting the stator core 21 are laminated by an adhesive portion 41 located at a plurality of points. Each adhesive portion 41 is an adhesive that is cured without separation. For example, a thermoset adhesive cured by polymer bonding or the like may be used for the adhesive portion 41. As the adhesive for forming the adhesive portion 41, an oily surface adhesive containing (1) acrylic resin, (2) epoxy resin, (3) acrylic resin and epoxy resin can be used. Therefore, the adhesive portion 41 contains an acrylic-based oil-based surface adhesive or an epoxy-based oil-based surface adhesive, or a combination thereof as the oil component. As an adhesive to form the adhesive part 41 in addition to thermosetting

- 4 040618 The adhesive may also use a radical polymerization adhesive or the like, and from the performance point of view, a room temperature-curing adhesive is preferably used. A room temperature curing adhesive cures at 20-30°C. As the room temperature curing adhesive, an acrylic based adhesive is preferred. A typical acrylic-based adhesive includes a second generation acrylic adhesive (SGA) or the like. An anaerobic adhesive, any of a moment adhesive and an acrylic-based elastomer adhesive, can be used in the range in which the effects of the present invention are not impaired. In addition, the adhesive used herein refers to the state before it is cured, and becomes the adhesive portion 41 after the adhesive is cured.

The average tensile modulus of the adhesive portions 41 at room temperature (20-30° C.) ranges from 2500 to 5000 MPa. When the average tensile modulus of the adhesive portions 41 is less than 2500 MPa, there is a problem of reducing the rigidity of the laminated core. Therefore, the lower limit value of the average tensile modulus of the adhesive portions 41 is set to 2500 MPa, and more preferably 3000 MPa. Conversely, when the average tensile modulus of the adhesive portions 41 exceeds 5000 MPa, the stress strain applied to the electrical steel sheet 40 increases, which causes the problem of deterioration of the core magnetism. Therefore, the value of the upper limit of the average tensile modulus of the adhesive parts 41 is set to 5000 MPa, and more preferably 4500 MPa. The average tensile modulus of each of the adhesive portions 41 can be adjusted by changing any or both of the heat and pressure conditions applied during bonding at the stacking station 140 and the types of hardener. In addition, the average tensile modulus is measured by the resonance method. In particular, the tensile modulus is measured in accordance with JIS R 1602:1995.

More specifically, a measurement sample (not shown) is first made. This pattern is obtained by bonding two electrical steel sheets 40 using the adhesive to be measured, and curing them to form an adhesive portion 41. When the adhesive is thermoset, curing is performed by heating and pressurizing under the heat and pressurization conditions used in actual operations. On the other hand, when the adhesive is curable at room temperature, curing is performed by pressurizing at room temperature. Then, the tensile modulus of the sample is measured by the resonance method. As described above, the tensile modulus measurement method using the resonance method is carried out in accordance with JIS R 1602:1995. Thereafter, when the effect of the electrical steel sheet 40 itself is excluded from the tensile modulus (measured value) by calculation, the tensile modulus of only the adhesive portion 41 can be obtained.

Since the sample's tensile modulus thus obtained is equal to the average value for the entire laminated core, this value is considered as the average tensile modulus. The composition is set in such a way that the average tensile modulus remains practically unchanged over all positions of the laminated package in the laying direction and circumferential positions around the central axis of the laminated core. Therefore, the average tensile modulus can also be set to the value with the cured adhesive portion 41 at the top end position of the laminated core.

As a method for gluing a plurality of electrical steel sheets 40, a gluing method in which the electrical steel sheets 40 are stacked on top of each other after adhesive is spotted on their bottom surfaces (on one side) and cured by performing either or both from heating and molding to form the adhesive portion 41. In addition, the heating means can be any means such as, for example, heating the stator core 21 in a high-temperature bath or electric furnace, or a heating method by directly supplying energy to the stator core 21. On the other hand, when a room temperature-curing adhesive is used, the electrical steel sheets 40 are only bonded to each other by pressing without heating.

Fig. 3 shows one example of the formation pattern of the adhesive portion 41. The adhesive portion 41 is formed at a plurality of round dots. More specifically, the adhesive portion 41 is formed in a dot shape with an average diameter of 12 mm in the core back portion 22 at equal angle intervals in the circumferential direction. In addition, at the distal end position of each tooth portion 23, an adhesive portion 41 is also formed in a dot shape with an average diameter of 8 mm. The median diameter given here is an example and may suitably be selected from the range of 2 mm to 20 mm. In addition, the formation pattern of FIG. 3 is an example, and the number and arrangement of the adhesive portions 41 can be suitably changed as needed. In addition, the shape of each adhesive portion 41 is not limited to only a round shape, but may be a rectangular shape or other polygonal shapes as needed.

The average thickness t2 of the adhesive portions 41 is 0.5 µm or more and 2.5 µm or less. When

- 5 040618 the average thickness t2 of the adhesive portions 41 is less than 0.5 µm, a sufficient adhesion force cannot be ensured. Therefore, the lower limit value of the average thickness t2 of the adhesive portions 41 is set to 0.5 µm, and more preferably 0.8 µm. Conversely, when the average thickness t2 of the adhesive portions 41 exceeds 2.5 µm, a problem arises such as a large increase in the amount of deformation in the electrical steel sheet 40 due to heat-setting shrinkage. Therefore, the upper limit value of the average thickness t2 of the adhesive portions 41 is set to 2.5 µm, and more preferably 2.0 µm. The average thickness t2 of the adhesive portions 41 is the average value over the entire laminated core. The average thickness t2 of the adhesive portions 41 remains practically unchanged in all laminating positions in the laying direction and circumferential positions around the central axis of the laminating core. Therefore, the average thickness t2 of the adhesive portions 41 can be set as the average of the numerical values measured at 10 or more points in the circumferential direction at the positions of the upper end of the laminated core. In addition, the average thickness of the adhesive portions 41 can be adjusted, for example, by changing the applied amount of adhesive.

In addition, in the glued laminated core for the stator, when the average thickness of the electrical steel sheets 40 is t1 in mm, the average thickness of the adhesive portions 41 is t2 in µm, and the average yield strength of the electrical steel sheets 40 is YP in MPa, either the condition A compliance with the following expressions 1, 2 and 3, or condition B compliance with the following expressions 3, 4 and 5, or a combination of them.

50xt1-12<t2<50xt1-6 (expression 1),

0.15<t1<0.27 (expression 2),

0.5<t2<2.5 (expression 3),

0.025xYP-12<t2<0.025xYP-8 (expression 4),

380<YP<540 (expression 5).

With regard to the above-described expression 1, when the average thickness t2 of the adhesive portions 41 is less than 50xt1-12, the adhesive strength between the steel sheets decreases. On the other hand, when the average thickness t2 of the adhesive portions 41 exceeds 50xt1-6, the amount of deformation of the electrical steel sheets 40 increases significantly due to the curing shrinkage of the adhesive. As described above, the average thickness t2 of the adhesive portions 41 is made in the range of expression 1.

With regard to the above expression 4, when the average thickness t2 of the adhesive portions 41 is less than 0.025xYP-12, the mechanical strength of the stator core 21 cannot be maintained. On the other hand, when the average thickness t2 of the adhesive portions 41 exceeds 0.025xYP-8, the stress applied to the laminated core increases due to curing shrinkage of the adhesive, and the magnetism of the core deteriorates. As described above, the average thickness t2 of the adhesive parts 41 is made in the range of expression 4.

In addition to the above description, when only condition A is satisfied or both conditions A and B are satisfied, it is more preferable that the average thickness t1 of the sheet is in the range of 0.20-0.25 mm and the average thickness t2 is in the range of 1.0 -2.0 µm. In addition, when only condition B is satisfied or both conditions A and B are satisfied, it is more preferable that the average thickness t2 is in the range of 1.0-2.0 µm and the average value YP of the yield strength is in the range of 450-500 MPa.

In the present embodiment, a plurality of electrical steel sheets forming the rotor core 31 are attached to each other by a fastener 42 (dowel) illustrated in FIG. 1. However, the plurality of electrical steel sheets constituting the rotor core 31 may also have an adhesive bonded laminated structure, as in the stator core 21. In addition, laminated cores such as the stator core 21 and the rotor core 31 can be formed by so-called wind stacking.

Example.

The stator core 21 was manufactured using the manufacturing apparatus 100 illustrated in FIG. 4, changing different production conditions. First, the production apparatus 100 will be described. In the production apparatus 100, while the electrical steel sheet P is fed in the direction of the arrow F from the roll C (steel sheet), the electrical steel sheet P is punched many times with a die located at each stage, gradually shaping electrical steel sheet 40, an adhesive is applied to the bottom surface of the electrical steel sheet 40, and the punched electrical steel sheet 40 is laminated and glued under pressure while the temperature is raised to form an adhesive portion 41.

As illustrated in FIG. 4, the production apparatus 100 includes a first-stage punching station 110 at a position proximal to coil C, a second-stage punching station 120 located adjacent to the punching station 110 on the exit side in the transport direction of the electrical steel sheet P, and an adhesive application station 130 located adjacent to the punching station 120 on the exit side further. The punching station 110 includes a fixed die 111 located below the electrical steel sheet P and a punch 112 located above the electrical steel sheet P. The punching station 120 includes a fixed die 121 located below the electrical steel sheet P, and a punch 122 positioned above the electrical steel sheet P. The glue application station 130 includes an applicator 131 having a plurality of nozzles arranged in a glue application pattern.

The production apparatus 100 further includes a stacking station 140 at a position downstream of the adhesive application station 130 . The stacking station 140 includes a heating device 141, a stationary external mold 142, a thermal insulation member 143, an internal shaping die 144, and a spring 145. A heating device 141, a stationary external shaping mold 142 and a heat insulating member 143 are disposed under the electrical steel sheet P. On the other hand, an internal shaping punch 144 and a spring 145 are disposed above the electrical steel sheet P. Reference numeral 21 denotes a stator core.

In the production apparatus 100 having the above-described structure, first, the electrical steel sheet P is successively fed from the roll C in the direction of the arrow F in FIG. 4. Next, punching processing of the electrical steel sheet P is performed at the punching station 110 . Then, punching processing of the electrical steel sheet P is performed at the punching station 120 . Due to these punching treatments of the electrical steel sheet P, the shape of the electrical steel sheet 40 with the core back portion 22 and the plurality of toothed portions 23 shown in FIG. 3. However, since the core is not completely punched out at this point, the processing proceeds to the next step in the direction of arrow F. At the glue application station 130, in the next step, the glue supplied from the nozzles of the applicator 131 is applied in a dotted form.

Finally, the electrical steel sheet P is sent to the laying station 140, punched out by a punching die 144 to form an internal shape, and laminated with high precision. At the time of lamination, the electrical steel sheet 40 receives a constant pressing force due to the spring 145. The above-described punching step, adhesive application step, and laminating step are sequentially repeated, and thereby a predetermined number of electrical steel sheets 40 can be laminated. the steel sheets 40 are thus heated, for example, to a temperature of 200° C. by the heating device 141. By heating, the adhesive is cured and an adhesive portion 41 is formed. As a result of the above-described steps, a stator core 21 is obtained.

The 21 stator cores shown with No. 1-31 in Table. 1A and tab. 1B were produced using the production apparatus 100 described above. The chemical components of the electrical steel sheet 40 used in the production of each of the stator cores 21 were unified as follows. All values of the concentration of the components are given in wt.%. In addition, in Table. 1A also shows the average value YP of the yield strength of each electrical steel sheet 40.

Si: 3.1%

Al: 0.7%

Mn: 0.3%, balance: Fe and impurities.

- 7 040618

Table 1A

No. Electrical steel sheet Insulating coating Adhesive part Average sheet thickness tl (mm) Average value of yield strength and UR (MPa) Average thickness (µm) Hat2 average thickness (µm) Average tensile modulus (MPa) Location drawing Is the expression 1(*a) satisfied? Does the expression 4(*b) Is condition A satisfied? Is condition B satisfied? 1 0.15 380 0.8 2.4 4000 Location in dot form not satisfied not satisfied not satisfied not satisfied 2 0.15 380 0.8 0.8 4000 Location in dot form satisfies satisfies satisfies satisfies 3 0.15 380 0.8 1.3 4000 Location in dot form satisfies satisfies satisfies satisfies 4 0.15 380 0.8 1.1 5800 Location in dot form satisfies satisfies satisfies satisfies 5 0.20 415 1.0 0.3 2000 Location in dot form satisfies satisfies not satisfied not satisfied 6 0.20 415 1.0 0.9 3800 Location in dot form satisfies satisfies satisfies satisfies 7 0.20 415 1.0 1.4 3800 Location in dot form satisfies satisfies satisfies satisfies 8 0.20 415 1.0 1.7 3800 Location in dot form satisfies satisfies satisfies satisfies 9 0.20 415 1.0 2.9 3800 Location in dot form satisfies satisfies not satisfied not satisfied 10 0.20 415 1.0 1.0 5800 Location in dot form satisfies satisfies satisfies satisfies eleven 0.23 460 0.8 0.4 4000 Location in dot form satisfies satisfies not satisfied not satisfied 12 0.23 460 0.8 1.1 4000 Location in dot form satisfies satisfies satisfies satisfies 13 0.23 460 0.8 1.9 4000 Location in dot form satisfies satisfies satisfies satisfies 14 0.23 460 0.8 3.0 4000 Location in dot form satisfies satisfies not satisfied not satisfied 15 0.23 460 0.8 1.0 5800 Location in dot form satisfies satisfies satisfies satisfies 16 0.25 500 0.8 0.4 3000 Location in dot form not satisfied not satisfied not satisfied not satisfied 17 0.25 500 0.8 1.4 3000 Location in dot form satisfies satisfies satisfies satisfies 18 0.25 500 0.8 2.0 3000 Location in dot form satisfies satisfies satisfies satisfies 19 0.25 500 0.8 2.4 3000 Location in dot form satisfies satisfies satisfies satisfies 20 0.25 500 0.8 2.7 3000 Location in dot form satisfies satisfies not satisfied not satisfied 21 0.25 500 0.8 1.0 2100 Location in dot form satisfies satisfies satisfies satisfies 22 0.27 530 0.9 0.7 4500 Location in dot form not satisfied not satisfied not satisfied not satisfied 23 0.27 530 0.9 1.8 4500 Location in dot form satisfies satisfies satisfies satisfies 24 0.27 530 0.9 2.2 4500 Location in dot form satisfies satisfies satisfies satisfies 25 0.27 530 0.9 3.4 4500 Location in dot form satisfies satisfies not satisfied not satisfied 26 0.27 530 0.9 1.4 2100 Location in dot form satisfies satisfies satisfies satisfies 27 0.30 555 1.1 1.3 2700 Location in dot form not satisfied not satisfied not satisfied not satisfied 28 0.30 555 1.1 1.4 2700 Location in dot form not satisfied not satisfied not satisfied not satisfied 29 0.30 555 1.1 3.2 2700 Location in dot form satisfies satisfies not satisfied not satisfied thirty 0.20 360 1.0 1.2 3800 Location in dot form satisfies satisfies satisfies not satisfied 31 0.30 475 1.1 2.0 2700 Location in dot form satisfies satisfies not satisfied satisfies

Table 1B

No. Mechanical strength Magnetic properties Inventive Example/Comparative Example MPa Grade W15/50 Grade 1 8 excellent 2.67 bad Comparative Example 2 7 excellent 2.33 Excellent Example according to the invention 3 8 excellent 2.39 Satisfactory Example according to the invention 4 9 excellent 2.70 bad Comparative Example 5 1 bad 2.32 Excellent Comparative Example 6 8 excellent 2.33 Excellent Example according to the invention 7 9 excellent 2.32 Excellent Example according to the invention 8 8 excellent 2.36 Excellent Example according to the invention 9 1 bad 2.54 bad Comparative Example 10 6 Satisfactory 2.66 bad Comparative Example eleven 1 bad 2.32 Excellent Comparative Example 12 9 excellent 2.31 Excellent Example according to the invention 13 9 excellent 2.29 Excellent Example according to the invention 14 8 excellent 2.57 bad Comparative Example 15 Satisfactory 2.55 bad Comparative Example 16 1 bad 2.38 Satisfactory Comparative Example 17 Satisfactory 2.37 Satisfactory Example according to the invention 18 10 excellent 2.38 Satisfactory Example according to the invention 19 8 excellent 2.39 Satisfactory Example according to the invention 20 6 Satisfactory 2.64 bad Comparative Example 21 3 bad 2.40 Satisfactory Comparative Example 22 2 bad 2.39 Satisfactory Comparative Example 23 10 excellent 2.40 Satisfactory Example according to the invention 24 9 excellent 2.41 Satisfactory Example according to the invention 25 6 Satisfactory 2.63 bad Comparative Example 26 1 bad 2.64 bad Comparative Example 27 3 bad 2.41 Satisfactory Comparative Example 28 3 bad 2.42 Satisfactory Comparative Example 29 2 bad 2.41 Satisfactory Comparative Example thirty 6 Satisfactory 2.46 Satisfactory Example according to the invention 31 5 Satisfactory 2.44 Satisfactory Example according to the invention

Specifically, a plurality of steel sheets (C rolls) having the above-described chemical components were prepared. The sheet thicknesses of the base steel sheets were of six types, including 0.15, 0.20, 0.23, 0.25, 0.27, and 0.30 mm. An insulating coating liquid containing a metal phosphate and an acrylic resin emulsion was applied to each of the steel sheets, and baking was performed at 300° C. to form an insulating coating with a thickness of 0.8 μm on one side. A single core plate (electrical steel sheet 40) which had a ring shape with an outer diameter of 300 mm and an inner diameter of 240 mm, and which was provided on the inner diameter side with 18 rectangular toothed portions 23 each having a length of 30 mm and a width of 15 mm, was molded by punching each of the sheet steels using the production device 100 described above. Then, sending the punched single plates in succession

- 8 040618 of the core, adhesive was applied in dot form in the positions illustrated in FIG. 3, and these single laminations were laminated and then cured by heating under compression at a predetermined pressure to form an adhesive portion 41. A laminated core (stator core 21) was produced by repeating the same operation for 130 single laminations.

The laminated core produced by the method described above was cut along its axis. Then the average thickness of the insulating coating was obtained. In addition, for the adhesive portion 41, an average thickness t2 (μm) and an average tensile modulus after curing were obtained. The average tensile modulus was obtained using the method described above. In addition, the outer diameter of each adhesive portion 41 averaged 5 mm. JIS Z 2241 method was used as a method for obtaining the average YP value of the yield strength of single core laminations. Then, the average thickness t1 (mm), the average thickness t2 (μm), and the average YP value (MPa) of the yield strength were substituted into the above expressions 1 and 4 to check if these expressions are satisfied. The results are shown in table. 1A. In addition, the average thickness t1 (mm) and the average thickness t2 (µm) were measured as described above.

In addition, the mechanical strength of the laminated core was also evaluated. When evaluating the mechanical strength, a cutting edge having a width of 20 mm and a distal end angle of 10° with a radius of 0.15 mm was pressed against the laminated part (between a pair of electrical steel sheets 40 adjacent to each other) of the laminated core with increasing load, and the magnitude of the load was estimated at its cracking. The higher the load, the better, and a load of 4 MPa or more was considered satisfactory or excellent. For mechanical strength in table. 1B, excellent indicates that high mechanical strength has been achieved, fair indicates that the necessary and sufficient mechanical strength has been achieved, and poor indicates that the minimum required mechanical strength has not been achieved. In addition, the magnetic properties of the laminated core were also evaluated. When evaluating the magnetic properties, the number of laminated electrical steel sheets 40 was set to 20, the winding was performed after the laminated core was covered with insulating paper, and the core loss (W15/50 in Table 1B) was measured at a frequency of 50 Hz and magnetic density. flow 1.5 Tl. Here, the number of laminated electrical steel sheets 40 for evaluation of magnetic properties was set to 20 because almost the same result can be obtained as in the case of 130 sheets. The lower the core loss (W15/50 in Table IB) the better, and a core loss of 2.50 or less was considered satisfactory or excellent. For magnetic properties in table. 1B, excellent indicates that very high magnetic properties have been achieved, satisfactory indicates that the necessary and sufficient magnetic properties have been achieved, and poor indicates that the magnetic properties are lower than the minimum required magnetic properties.

In addition, FIG. 5 shows a graph summarizing those shown in the table. 1A results as a ratio between the average thickness t1 of the electrical steel sheets 40 and the average thickness t2 of the adhesive portions 41. Similarly, FIG. 6 shows a graph summarizing those shown in the table. 1A results as a ratio between the average yield strength YP of the electrical steel sheets 40 and the average thickness t2 of the adhesive portions 41.

As shown in Table. 1A and table. 1B, in the comparative example shown in No. 1, since expressions 1 and 4 were not satisfied, the magnetic properties deteriorated. In addition, in the comparative example shown in No. 4, since the unit strength of the adhesive portion was too high, the voltage applied to the electrical steel sheet was too high, and the magnetic properties deteriorated. In addition, in the comparative example shown in No. 5, the average thickness t2 of the adhesive portions was too small, which means that sufficient adhesion force could not be obtained. In addition, in the comparative example shown in No. 9, the average thickness t2 of the adhesive portions was too large compared to the small average thickness t1 of the electrical steel sheet. As a result, deformation occurred in the electrical steel sheet and the magnetic properties deteriorated. In addition, in the comparative example shown in No. 10, since the unit strength of the adhesive portion was too high, the voltage applied to the electrical steel sheet was too high, and the magnetic properties deteriorated.

In addition, in the comparative example shown in No. 11, the average thickness t2 of the adhesive portions was too small, and sufficient adhesive strength could not be obtained. In addition, in the comparative example shown in No. 14, the average thickness t2 of the adhesive portions was too large, the proportion occupied by the electrical steel sheet in the laminated core decreased, and the magnetic property of the laminated core deteriorated. In addition, in the comparative example shown in No. 15, since the unit strength of the adhesive portion was too high, the voltage applied to the electrical steel sheet was too high, and the magnetic properties deteriorated. In addition, in the comparative example shown in No. 16, the average thickness t2 of the adhesive portions was too small, and sufficient adhesive strength could not be obtained.

In addition, in the comparative example shown in No. 20, the average thickness t2 of the adhesive portions was

- 9 040618 is too large, the proportion occupied by the electrical steel sheet in the laminated core has decreased, and the magnetic property of the laminated core has deteriorated. In addition, in the comparative example shown in No. 21, the adhesive portion was too soft and the mechanical strength deteriorated. In addition, in the comparative example shown in No. 22, since Expressions 1 and 4 were not satisfied, the mechanical strength deteriorated.

In addition, in the comparative example shown in No. 25, the average thickness t2 of the adhesive portions was too large, which caused deformation of the electrical steel sheet, and this affected the magnetic properties. In addition, in the comparative example shown in No. 26, the adhesive portion was too soft, which caused the electrical steel sheet to deform, and both the mechanical strength and the magnetic properties deteriorated. In addition, in the Comparative Examples shown in Nos. 27-29, since the average thickness t1 of the electrical steel sheets was too large, the strength of the adhesive part decreased relatively, and the mechanical strength of the laminated core decreased.

On the other hand, in Examples of the present invention, including Nos. 2, 3, 6-8, 12, 13, 17-19, 23, 24, 30, and 31, the desired characteristics in terms of both mechanical strength and magnetic properties were confirmed. laminated core. Among these Inventive Examples, Nos. 2, 3, 6-8, 12, 13, 17-19, 23, and 24 satisfied both Condition A and Condition B, and thus showed better results than Nos. 30 and 31, which satisfy only one of condition A and condition B.

One embodiment and examples of the present invention have been described above. However, the technical scope of the present invention is not limited to the above-described embodiment and examples, and various modifications can be made without departing from the gist of the present invention. For example, the shape of the stator core 21 is not limited to only the shape illustrated in the above-described embodiment. In particular, the outer diameter and inner diameter, the thickness of the laminated stack and the number of slots of the stator core 21, the size ratio of the tooth portion 23 in the circumferential direction and the radial direction, the size ratio in the radial direction between the tooth portion 23 and the core back portion 22, and the like. can be designed arbitrarily according to the desired characteristics of the electric motor. In the rotor 30 of the above embodiment, a set of two permanent magnets 32 forms one magnetic pole, but the present invention is not limited to this kind. For example, one permanent magnet 32 may form one magnetic pole, or three or more permanent magnets 32 may form one magnetic pole.

In the above-described embodiment, a constant magnetic field motor has been described as an example of the motor 10, but the structure of the motor 10 is not limited to only this as will be illustrated below, and in addition, various well-known structures not illustrated below can also be used. In the above embodiment, the constant magnetic motor is described as an example of the motor 10, but the present invention is not limited thereto. For example, the motor 10 may also be a reluctance motor or an electromagnetically excited motor (field motor). In the above embodiment, the synchronous motor has been described as an example of an AC motor, but the present invention is not limited thereto. For example, motor 10 may also be an induction motor. In the above embodiment, an AC motor has been described as an example of the electric motor 10, but the present invention is not limited thereto. For example, motor 10 may be a DC motor. In the above embodiment, a motor has been described as an example of the electric motor 10, but the present invention is not limited thereto. For example, motor 10 may be a generator.

In addition, the components in the above-described embodiments may be appropriately substituted with well-known components within the range of the gist of the present invention, and the above-described modified examples may be appropriately combined.

Industrial Applicability

According to the present invention, it is possible to provide a bonded-laminated stator core in which magnetic deterioration due to curing shrinkage of an adhesive can be suppressed, as well as a motor including such a bonded-laminated stator core. Therefore, the industrial applicability is high.

Brief description of reference symbols:

- electric motor,

- glued laminated core for the stator,

- electrical steel sheet,

- adhesive part.

Claims (6)

CLAIM 1. Glued-laminated core for the stator, containing: a plurality of electrical steel sheets laminated to each other, each of which is coated on both sides with an insulating coating; and an adhesive part disposed at a plurality of points between each of the electrical steel sheets adjacent to each other in the laying direction, and configured to cause each of the electrical steel sheets to be glued to each other, the chemical composition of each of the electrical steel sheets being 2.5 to 3 9% Si by mass, the average tensile modulus of each of the adhesive portions is 2500 to 5000 MPa, and when the average thickness of each of the electrical steel sheets is t1 in mm, the average thickness of each of the adhesive portions is t2 in µm, and the average the value of the yield strength of each of the electrical steel sheets is YP in MPa, all of the following expressions are satisfied: 50xt1-12<t2<50xt1-6, 0.15<t1<0.27, 0.5<t2<2.5, 0.025xYP-12<t2<0.025xYP-8, 380<YP<540. 2. The glued-laminated stator core according to claim 1, wherein the average sheet thickness t1 is in the range of 0.20 to 0.25 mm and the average thickness t2 is in the range of 1.0 to 2.0 µm. 3. The glued-laminated stator core according to claim 1, wherein the average thickness t2 is in the range of 1.0 to 2.0 µm and the average value YP of the yield strength is in the range of 450 to 500 MPa. 4. A bonded-laminated stator core according to any one of claims 1 to 3, wherein each of the adhesive portions contains an acrylic-based oil-based surface adhesive or an epoxy-based oil-based surface adhesive, or a combination thereof as the oil component. 5. The bonded-laminated stator core of any one of claims 1 to 3, wherein each of the adhesive portions is a room temperature curing acrylic-based adhesive containing a second generation acrylic adhesive (SGA) comprising an elastomer-containing acrylic-based adhesive. 6. An electric motor comprising a bonded laminated stator core according to any one of claims 15.