Laminated iron core and rotating electrical machine

Abstract

A laminated iron core is a laminated iron core comprising a plurality of electromagnetic steel plates stacked on each other, wherein the electromagnetic steel plates located on a first side along the stacking direction and the electromagnetic steel plates located on a second side along the stacking direction are riveted to each other but not bonded, and the electromagnetic steel plates located in the center along the stacking direction are bonded to each other but not riveted.

Description

Technical Field

[0001] The present invention relates to a laminated iron core and a rotating electric machine.

[0002] This application claims priority based on Japanese Patent Application No. 2018-235851 filed in Japan on December 17, 2018, the contents of which are incorporated herein by reference. Background Art

[0003] Conventionally, there is known a laminated iron core as described in the following Patent Document 1. In this laminated iron core, electromagnetic steel sheets adjacent to each other in the lamination direction are joined by both bonding and caulking.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-136228 Summary of the Invention

[0007] [Technical problem to be solved by the invention]

[0008] The conventional laminated core described above still has room for improvement in terms of ensuring dimensional accuracy of the outer shape and improving magnetic properties.

[0009] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to improve magnetic properties while ensuring dimensional accuracy of the outer shape.

[0010] [Technical means for solving technical problems]

[0011] In order to solve the above technical problems, the present invention proposes the following means.

[0012] (1) A first embodiment of the present invention is a laminated iron core comprising a plurality of electromagnetic steel plates stacked on one another, wherein the electromagnetic steel plates located on a first side along a stacking direction and the electromagnetic steel plates located on a second side along the stacking direction are riveted to one another but not bonded, and the electromagnetic steel plates located in the center along the stacking direction are bonded to one another but not riveted.

[0013] Compared to bonding-based bonding, riveting-based bonding can improve dimensional accuracy. Here, the electromagnetic steel plates located on the first side along the stacking direction and the electromagnetic steel plates located on the second side along the stacking direction among the multiple electromagnetic steel plates are riveted to each other. Therefore, the shape accuracy of each part located on the first side and the second side of the laminated core (each part located on the outside of the laminated core relative to the center of the laminated core) can be improved. These parts have a greater impact on the outer shape of the laminated core than the part located in the center of the laminated core. Therefore, by improving the shape accuracy of these parts, the outer shape accuracy of the laminated core can be improved as a result. Therefore, the handleability of the laminated core can be ensured. For example, even when winding is wound around the laminated core, it can be wound with good precision.

[0014] Compared to riveting, bonding can suppress strain in the electromagnetic steel sheets. Strain in the electromagnetic steel sheets affects their iron loss and the magnetic properties of the laminated core, so it is preferably kept small. Here, the electromagnetic steel sheets located centrally along the stacking direction are bonded together. This suppresses strain compared to riveting these sheets. As a result, the magnetic properties of the laminated core can be improved.

[0015] (2) It may also be that, in the laminated iron core described in (1), the number of the electromagnetic steel sheets located in the center and bonded to each other is greater than the number of the electromagnetic steel sheets located on the first side and riveted to each other, and the number of the electromagnetic steel sheets located on the second side and riveted to each other.

[0016] The number of electromagnetic steel sheets bonded together in the center (hereinafter referred to as N3) is greater than the number of electromagnetic steel sheets riveted together on the first side (hereinafter referred to as N1) and the number of electromagnetic steel sheets riveted together on the second side (hereinafter referred to as N2). Therefore, the ratio of the number of electromagnetic steel sheets riveted together in the entire laminated core can be reduced. As a result, the magnetic properties of the laminated core can be further improved.

[0017] (3) In the laminated iron core described in (1) or (2), the number of electromagnetic steel sheets located on the first side and riveted to each other may be equal to the number of electromagnetic steel sheets located on the second side and riveted to each other.

[0018] N1 and N2 are equal. Therefore, in the laminated core, a difference in dimensional accuracy between the first side and the second side in the lamination direction can be suppressed. This further ensures the handleability of the laminated core.

[0019] (4) Alternatively, in the laminated iron core described in any one of (1) to (3), the electromagnetic steel plate includes: an annular core back; and a plurality of teeth protruding from the core back in the radial direction of the core back and arranged at intervals in the circumferential direction of the core back.

[0020] The laminated core is a stator core comprising a core back and teeth. Therefore, for example, when windings are passed through slots between circumferentially adjacent teeth, the aforementioned processability is significantly enhanced. Specifically, improved slot dimensional accuracy makes it easier to wind the windings around the teeth as designed. This increases the winding space factor within the slots, resulting in a higher current carrying capacity within the slots.

[0021] (5) In the laminated iron core according to any one of (1) to (4), an average thickness of the bonding portion may be 1.0 μm to 3.0 μm.

[0022] (6) In the laminated iron core according to any one of (1) to (5), an average tensile modulus E of the bonding portion may be 1500 MPa to 4500 MPa.

[0023] (7) In the laminated iron core described in any one of (1) to (6), the bonding portion may be a room temperature bonding type acrylic adhesive including SGA, wherein the SGA is composed of an acrylic adhesive containing an elastomer.

[0024] (8) A second aspect of the present invention is a rotating electrical machine including the laminated iron core described in any one of (1) to (7).

[0025] [Effects of the Invention]

[0026] According to the present invention, it is possible to ensure dimensional accuracy of the outer shape and improve magnetic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a cross-sectional view of a rotating electrical machine according to one embodiment of the present invention.

[0028] Figure 2 yes Figure 1 A plan view of a stator included in the rotating electrical machine shown.

[0029] Figure 3 yes Figure 1 A side view of a stator included in the rotating electrical machine shown.

[0030] Figure 4 yes Figure 1 A plan view of electromagnetic steel sheets and bonding portions of a stator included in the rotating electrical machine shown.

[0031] Figure 5 yes Figure 1 A plan view of electromagnetic steel plates and rivets of a stator included in the illustrated rotating electrical machine.

[0032] Figure 6 yes Figure 5 The VI-VI sectional view is shown.

[0033] Figure 7 This is a cross-sectional view of a stator core according to a first modified example of an embodiment of the present invention, which is equivalent to Figure 6 The cross-sectional view shown in FIG.

[0034] Figure 8 This is a cross-sectional view of a stator core according to a second modified example of an embodiment of the present invention, which is equivalent to Figure 6 The cross-sectional view shown in FIG. DETAILED DESCRIPTION

[0035] A rotating electrical machine according to one embodiment of the present invention will be described below with reference to the accompanying 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, is used as an example of the rotating electrical machine. This type of motor is preferably used in, for example, electric vehicles.

[0036] like Figure 1 and Figure 2 As shown, the rotary electric machine 10 includes a stator 20, a rotor 30, a housing 50, and a rotating shaft 60. The stator 20 and the rotor 30 are accommodated in the housing 50. The stator 20 is fixed to the housing 50.

[0037] In this embodiment, an inner rotor type is used as the rotating electrical machine 10, in which the rotor 30 is located inside the stator 20. However, an outer rotor type may also be used, in which the rotor 30 is located outside the stator 20. Furthermore, in this embodiment, the rotating electrical machine 10 is a three-phase AC motor having 12 poles and 18 slots. However, for example, the number of poles, slots, and phases can be modified as appropriate. Furthermore, for example, by applying an excitation current of 10A effective value and a frequency of 100 Hz to each phase, the rotating electrical machine 10 can rotate at 1000 rpm.

[0038] The stator 20 includes a stator core 21 and windings (not shown).

[0039] The stator core 21 includes an annular core back 22 and a plurality of teeth 23. Hereinafter, the axial direction of the stator core 21 (core back 22) (the direction of the central axis O of the stator core 21) is referred to as the axial direction, the radial direction of the stator core 21 (core back 22) (the direction orthogonal to the central axis O of the stator core 21) is referred to as the radial direction, and the circumferential direction of the stator core 21 (core back 22) (the direction surrounding the central axis O of the stator core 21) is referred to as the circumferential direction.

[0040] The core back 22 is formed in an annular shape in a plan view of the stator 20 viewed from the axial direction.

[0041] The plurality of teeth 23 protrude radially inward from the core back 22 (radially toward the center axis O of the core back 22). The plurality of teeth 23 are arranged at equal intervals along the circumferential direction. In this embodiment, 18 teeth 23 are provided at 20-degree central angles centered on the center axis O. The plurality of teeth 23 are formed to have the same shape and size. Furthermore, the shapes and sizes of the plurality of teeth 23 may vary.

[0042] The winding is wound around the teeth 23. The winding may be concentratedly wound or dispersedly wound.

[0043] The rotor 30 is arranged radially inward of the stator 20 (stator core 21 ) and includes a rotor core 31 and a plurality of permanent magnets 32 .

[0044] The rotor core 31 is formed into an annular shape (ring shape) coaxially arranged with the stator 20. The rotating shaft 60 is arranged in the rotor core 31. The rotating shaft 60 is fixed to the rotor core 31.

[0045] Multiple permanent magnets 32 are fixed to the rotor core 31. In this embodiment, a set of two permanent magnets 32 forms a single magnetic pole. The multiple sets of permanent magnets 32 are arranged at equal intervals along the circumferential direction. In this embodiment, 12 sets (24 in total) of permanent magnets 32 are arranged at 30-degree intervals around the central axis O. The spacing between the multiple sets of permanent magnets 32 does not have to be equal.

[0046] In this embodiment, an embedded magnet type motor is used as a permanent magnet field type motor. A plurality of through holes 33 are formed on the rotor core 31, which penetrate the rotor core 31 in the axial direction. The plurality of through holes 33 are provided corresponding to the plurality of permanent magnets 32. Each permanent magnet 32 is fixed to the rotor core 31 in a state where it is arranged in a corresponding through hole 33. The fixing of each permanent magnet 32 to the rotor core 31 can be achieved by bonding the outer surface of the permanent magnet 32 to the inner surface of the through hole 33 with an adhesive. In addition, as a permanent magnet field type motor, a surface magnet type motor can also be used instead of the embedded magnet type motor.

[0047] Both the stator core 21 and the rotor core 31 are laminated cores formed by laminating a plurality of electromagnetic steel sheets 40 .

[0048] In addition, the stacking thickness of each of the stator core 21 and the rotor core 31 is set to 50.0 mm, for example. The outer diameter of the stator core 21 is set to 250.0 mm, for example. The inner diameter of the stator core 21 is set to 165.0 mm, for example. The outer diameter of the rotor core 31 is set to 163.0 mm, for example. The inner diameter of the rotor core 31 is set to 30.0 mm, for example. However, these values are examples, 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 front end portion of the tooth portion 23 in the stator core 21. The inner diameter of the stator core 21 is the diameter of an imaginary circle inscribed in the front end portions of all the teeth 23.

[0049] The electromagnetic steel sheets 40 forming the stator core 21 and the rotor core 31 are formed, for example, by punching an electromagnetic steel sheet serving as a base material. A known electromagnetic steel sheet can be used as the electromagnetic steel sheet 40. The chemical composition of the electromagnetic steel sheet 40 is not particularly limited. In this embodiment, a non-oriented electromagnetic steel sheet is used as the electromagnetic steel sheet 40. For example, a non-oriented electrical steel strip according to JIS C2552:2014 can be used as the non-oriented electromagnetic steel sheet. However, instead of a non-oriented electromagnetic steel sheet, a oriented electromagnetic steel sheet can be used as the electromagnetic steel sheet 40. For example, a oriented electrical steel strip according to JIS C2553:2012 can be used as the oriented electromagnetic steel sheet.

[0050] In order to improve the workability of the electromagnetic steel sheet or the iron loss of the laminated core, both surfaces of the electromagnetic steel sheet 40 are covered with an insulating film. As a material constituting the insulating film, for example, (1) an inorganic compound, (2) an organic resin, (3) a mixture of an inorganic compound and an organic resin, etc. can be used. Examples of the inorganic compound include (1) a complex of dichromate and boric acid, and (2) a complex of phosphate and silicon dioxide. Examples of the organic resin include epoxy resin, acrylic resin, acrylic styrene resin, polyester resin, silicone resin, fluororesin, etc.

[0051] In order to ensure the insulation performance between the stacked electromagnetic steel sheets 40 , the thickness of the insulating film (the thickness per one side of the electromagnetic steel sheet 40 ) is preferably 0.1 μm or more.

[0052] On the other hand, as the insulating coating becomes thicker, the insulation effect saturates. Furthermore, as the insulating coating becomes thicker, the space factor decreases, and the performance as a laminated core deteriorates. Therefore, it is better to make the insulating coating thinner while ensuring insulation performance. The thickness of the insulating coating (the thickness per surface of the electromagnetic steel sheet 40) is preferably 0.1 μm to 5 μm, and more preferably 0.1 μm to 2 μm.

[0053] As the electromagnetic steel sheet 40 becomes thinner, the iron loss improvement effect gradually saturates. Furthermore, the manufacturing cost of the electromagnetic steel sheet 40 increases as the electromagnetic steel sheet 40 becomes thinner. Therefore, considering the iron loss improvement effect and manufacturing cost, the thickness of the electromagnetic steel sheet 40 is preferably 0.10 mm or greater.

[0054] On the other hand, if the electromagnetic steel sheet 40 is too thick, it becomes difficult to perform press punching of the electromagnetic steel sheet 40. Therefore, considering the press punching of the electromagnetic steel sheet 40, the thickness of the electromagnetic steel sheet 40 is preferably 0.65 mm or less.

[0055] Furthermore, if the electromagnetic steel sheet 40 becomes thicker, the iron loss increases. Therefore, considering the iron loss characteristics of the electromagnetic steel sheet 40, the thickness of the electromagnetic steel sheet 40 is preferably 0.35 mm or less, more preferably 0.20 mm or 0.25 mm.

[0056] Considering the above aspects, the thickness of each electromagnetic steel sheet 40 is preferably 0.10 mm to 0.65 mm, more preferably 0.10 mm to 0.35 mm, and even more preferably 0.20 mm or 0.25 mm. The thickness of the electromagnetic steel sheet 40 also includes the thickness of the insulation coating.

[0057] Parts of the plurality of electromagnetic steel sheets 40 forming the stator core 21 are bonded together by bonding portions 41. The bonding portions 41 are adhesives that are provided between the electromagnetic steel sheets 40 adjacent to each other in the stacking direction and that cure without breaking. As the adhesive, for example, a thermosetting adhesive based on polymerization bonding is used. As adhesive compositions, (1) acrylic resins, (2) epoxy resins, (3) compositions containing acrylic resins and epoxy resins, etc. can be applied. As such adhesives, in addition to thermosetting adhesives, free radical polymerization adhesives can also be used. From the perspective of productivity, it is preferred to use room temperature curing adhesives. Room temperature curing adhesives cure at 20°C to 30°C. As room temperature curing adhesives, acrylic adhesives are preferred. Representative acrylic adhesives include SGA (Second Generation Acrylic Adhesive). Any of anaerobic adhesives, instant adhesives, and acrylic adhesives containing elastomers can be used without impairing the effects of the present invention. The adhesive referred to here is in a state before curing, and the adhesive forms the bonding portion 41 after curing.

[0058] The average tensile modulus E of the adhesive portion 41 at room temperature (20°C to 30°C) is within the range of 1500 MPa to 4500 MPa. If the average tensile modulus E of the adhesive portion 41 is less than 1500 MPa, the rigidity of the laminated core will be reduced, which is a disadvantage. Therefore, the lower limit of the average tensile modulus E of the adhesive portion 41 is set to 1500 MPa, and more preferably 1800 MPa. On the other hand, if the average tensile modulus E of the adhesive portion 41 exceeds 4500 MPa, the insulating film formed on the surface of the electromagnetic steel sheet 40 will be peeled off. Therefore, the upper limit of the average tensile modulus E of the adhesive portion 41 is set to 4500 MPa, and more preferably 3650 MPa.

[0059] Furthermore, the average tensile elastic modulus E was measured by a resonance method. Specifically, the tensile elastic modulus was measured in accordance with JIS R 1602:1995.

[0060] More specifically, a sample for measurement (not shown) is first produced. This sample is obtained by bonding two electromagnetic steel sheets 40 with the adhesive to be measured and curing the adhesive to form a bonded portion 41. If the adhesive is thermosetting, curing is performed by applying heat and pressure under actual operating conditions. On the other hand, if the adhesive is room-temperature curing, curing is performed by applying pressure at room temperature.

[0061] The tensile modulus of the sample is then measured using the resonance method. The method for measuring the tensile modulus using the resonance method is as described above and is performed in accordance with JIS R 1602:1995. The tensile modulus of the adhesive portion 41 alone is then calculated, excluding the influence of the electromagnetic steel sheet 40 itself from the tensile modulus of the sample (measured value).

[0062] Since the tensile modulus obtained from the sample in this manner is equal to the average value for the entire laminated core, this value is considered the average tensile modulus E. The composition of the average tensile modulus E is set so that it hardly changes depending on the stacking position along the stacking direction or the circumferential position around the central axis of the laminated core. Therefore, the value measured at the cured adhesive portion 41 at the upper end of the laminated core can also be used as the value of the average tensile modulus E.

[0063] As a bonding method, for example, an adhesive may be applied to the electromagnetic steel sheet 40 and then bonded by heating, pressing, or both. Furthermore, the heating method may be any method such as heating in a high-temperature tank or electric furnace or directly applying electricity.

[0064] In order to stably obtain sufficient bonding strength, the thickness of the bonding portion 41 is preferably 1 μm or more.

[0065] On the other hand, if the thickness of the adhesive portion 41 exceeds 100 μm, the adhesive force will saturate. Furthermore, as the thickness of the adhesive portion 41 increases, the space factor decreases, and the torque density when the laminated iron core is used as a motor decreases. Therefore, the thickness of the adhesive portion 41 is preferably 1 μm to 100 μm, more preferably 1 μm to 10 μm.

[0066] Furthermore, in the above, the thickness of the adhesive portion 41 indicates the average thickness of the adhesive portion 41 .

[0067] The average thickness of the adhesive portion 41 is preferably greater than 1.0 μm and less than 3.0 μm. If the average thickness of the adhesive portion 41 is less than 1.0 μm, sufficient bonding strength cannot be ensured as described above. Therefore, the lower limit of the average thickness of the adhesive portion 41 is 1.0 μm, and more preferably 1.2 μm. Conversely, if the average thickness of the adhesive portion 41 exceeds 3.0 μm, undesirable conditions may occur, such as a significant increase in the strain of the electromagnetic steel sheet 40 due to shrinkage during thermal curing. Therefore, the upper limit of the average thickness of the adhesive portion 41 is set to 3.0 μm, and more preferably 2.6 μm.

[0068] The average thickness of the adhesive portion 41 is the average value of the entire laminated core. The average thickness of the adhesive portion 41 is substantially constant at any position along the lamination direction or at any circumferential position around the central axis of the laminated core. Therefore, the average thickness of the adhesive portion 41 can be determined by averaging the values measured at the top end of the laminated core at ten or more circumferential positions.

[0069] Furthermore, the average thickness of the adhesive portion 41 can be adjusted, for example, by changing the amount of adhesive applied. Furthermore, in the case of a thermosetting adhesive, for example, the average tensile modulus E of the adhesive portion 41 can be adjusted by changing one or both of the heating and pressurizing conditions applied during bonding and the type of curing agent.

[0070] In the present embodiment, the plurality of electromagnetic steel sheets 40 forming the rotor core 31 are fixed to each other by caulking (dowels) C. However, the plurality of electromagnetic steel sheets 40 forming the rotor core 31 may be bonded to each other by bonding portions 41 .

[0071] Furthermore, a laminated core such as the stator core 21 or the rotor core 31 may be formed by so-called rotational stacking.

[0072] Here, if Figure 3 and Figure 4 As shown, in the stator core 21 of this embodiment, all pairs of adjacent electromagnetic steel sheets 40 in the stacking direction are joined by either bonding or riveting. In this embodiment, among the plurality of electromagnetic steel sheets 40, the N1 electromagnetic steel sheets 40 located on the first side D1 in the stacking direction (hereinafter referred to as the first stack 76) and the N2 electromagnetic steel sheets 40 located on the second side D2 in the stacking direction (hereinafter referred to as the second stack 77) are riveted, not bonded, and are not joined by any other joining method. Among the plurality of electromagnetic steel sheets 40, the N3 electromagnetic steel sheets 40 located in the center in the stacking direction (hereinafter referred to as the third stack 78) are bonded, not riveted, and are not joined by any other joining method.

[0073] Of the two ends of the stator core 21 in the stacking direction, the end located on the first side D1 is the first end 21a, and the end located on the second side D2 is the second end 21b. The first end 21a is formed by the N1 electromagnetic steel sheets 40 (the first stack 76). The second end 21b is formed by the N2 electromagnetic steel sheets 40 (the second stack 77). In this embodiment, N1 and N2 are equal. Here, the case where N1 and N2 are equal includes not only the case where N1 and N2 are completely equal, but also the case where there is a slight difference between N1 and N2 (the case where they are substantially equal). This slight difference refers to a difference in the number of sheets within 5% relative to the total number of sheets in the stator core 21.

[0074] like Figure 5 As shown, rivets C1 and C2 are formed on the riveted electromagnetic steel sheets 40 (the electromagnetic steel sheets 40 of the N1 sheet and the N2 sheet, the first stack 76, and the second stack 77). The rivets C1 and C2 include a first rivet C1 provided on the core back 22 and a second rivet C2 provided on the teeth 23.

[0075] Multiple first rivets C1 are arranged at equal intervals along the circumferential direction. In the illustrated example, the first rivets C1 are arranged circumferentially staggered relative to the teeth 23. The first rivets C1 are positioned between adjacent teeth 23 along the circumferential direction. The first rivets C1 are radially positioned in the center of the core back 22.

[0076] The second rivet C2 is provided on all the teeth 23. The second rivet C2 is arranged at the center in the circumferential direction of each tooth 23. Two second rivets C2 are arranged in parallel in the radial direction of each tooth 23.

[0077] like Figure 6 As shown, the first rivet C1 includes a protrusion C11 and a recess C12 provided on each electromagnetic steel sheet 40. The protrusion C11 protrudes from the electromagnetic steel sheet 40 in the stacking direction. In each electromagnetic steel sheet 40, the recess C12 is located on the back side of the protrusion C11. The recess C12 is recessed relative to the surface (first surface) of the electromagnetic steel sheet 40 in the stacking direction. The protrusion C11 and recess C12 are formed by, for example, stamping each electromagnetic steel sheet 40.

[0078] Here, in each of the N1 electromagnetic steel sheets 40 (first stack 76) and the N2 electromagnetic steel sheets 40 (second stack 77), one of the two electromagnetic steel sheets 40 adjacent in the stacking direction is referred to as the first electromagnetic steel sheet 40, and the other is referred to as the second electromagnetic steel sheet 40. The first rivet C1 is formed by fitting the protrusion C11 of the first electromagnetic steel sheet 40 into the recess C12 of the second electromagnetic steel sheet 40. The fitting of the protrusion C11 into the recess C12 forms the first rivet C1, thereby restricting relative displacement between the two electromagnetic steel sheets 40 adjacent in the stacking direction.

[0079] The second rivet C2 has the same structure as the first rivet C1. It includes the protrusion C11 and the recess C12 provided on each electromagnetic steel sheet 40. The second rivet C2 is formed by fitting the protrusion C11 of the first electromagnetic steel sheet 40 into the recess C12 of the second electromagnetic steel sheet 40. The protrusion C11 fits into the recess C12, forming the second rivet C2. This restricts relative displacement between two adjacent electromagnetic steel sheets 40 in the stacking direction.

[0080] In addition, the shapes of the convex portion C11 and the concave portion C12 are not particularly limited.

[0081] In addition, the direction in which the convex portion C11 protrudes and the direction in which the concave portion C12 is recessed may be either the first side D1 or the second side D2 in the stacking direction.

[0082] For example, it can also be, Figure 6 As shown in the stator core 21 of the present embodiment, in either the N1 electromagnetic steel sheet 40 (first stack 76) or the N2 electromagnetic steel sheet 40 (second stack 77), the convex portion C11 protrudes toward the second side D2, while the concave portion C12 is recessed toward the second side D2. In this case, in each of the N1 electromagnetic steel sheet 40 (first stack 76) and the N2 electromagnetic steel sheet 40 (second stack 77), the convex portion C11 and concave portion C12 may be formed on the electromagnetic steel sheet 40 located closest to the second side D2. However, in the illustrated example, the electromagnetic steel sheet 40 located closest to the second side D2 has a through-hole C13 formed therein, replacing the convex portion C11 and concave portion C12. In this case, the convex portion C11 of the electromagnetic steel sheet 40 adjacent to the electromagnetic steel sheet 40 on the first side D1 is embedded in the through-hole C13. Thus, in each of the N1 electromagnetic steel sheets 40 (first stacked body 76 ) and the N2 electromagnetic steel sheets 40 (second stacked body 77 ), the two electromagnetic steel sheets 40 located closest to the second side D2 are caulked to each other.

[0083] Furthermore, it can also be, for example Figure 7 As shown in the stator core 21A of the first modified example, in the N1 electromagnetic steel sheet 40 (first stack 76), the convex portion C11 protrudes toward the second side D2, and the concave portion C12 is recessed toward the second side D2. Alternatively, in the N2 electromagnetic steel sheet 40 (second stack 77), the convex portion C11 protrudes toward the first side D1, and the concave portion C12 is recessed toward the first side D1. In the illustrated example, in the N1 electromagnetic steel sheet 40 (first stack 76), the electromagnetic steel sheet 40 located closest to the second side D2 has a through-hole C13 formed in place of the convex portion C11 and the concave portion C12. Furthermore, in the N2 electromagnetic steel sheet 40 (second stack 77), the electromagnetic steel sheet 40 located closest to the first side D1 has a through-hole C13 formed in place of the convex portion C11 and the concave portion C12.

[0084] And, it can also be, for example, Figure 8As shown in the stator core 21B of the second modified example, in the N1 electromagnetic steel sheets 40 (first stack 76), the convex portion C11 protrudes toward the first side D1, and the concave portion C12 is recessed toward the first side D1. Furthermore, in the N2 electromagnetic steel sheets 40 (second stack 77), the convex portion C11 protrudes toward the second side D2, and the concave portion C12 is recessed toward the second side D2. In the illustrated example, in the N1 electromagnetic steel sheets 40 (first stack 76), the electromagnetic steel sheet 40 located closest to the first side D1 has a through-hole C13 formed in place of the convex portion C11 and the concave portion C12. Furthermore, in the N2 electromagnetic steel sheets 40 (second stack 77), the electromagnetic steel sheet 40 located closest to the second side D2 has a through-hole C13 formed in place of the convex portion C11 and the concave portion C12.

[0085] Although not shown, in either the N1 electromagnetic steel sheet 40 (first stack 76 ) or the N2 electromagnetic steel sheet 40 (second stack 77 ), the convex portions C11 may protrude toward the first side D1 and the concave portions C12 may be recessed toward the first side D1 .

[0086] like Figure 3 As shown, the N1 electromagnetic steel sheets 40 (first stack 76) and the N2 electromagnetic steel sheets 40 (second stack 77) sandwich the N3 electromagnetic steel sheets 40 (third stack 78), located in the center of the stacking direction, from both sides of the stacking direction. The N3 electromagnetic steel sheets 40 (third stack 78) form the central portion 21c of the stator core 21. Let N0 be the total number of electromagnetic steel sheets 40. N0 can be calculated as the sum of N1, N2, and N3.

[0087] like Figure 4 As shown, the electromagnetic steel sheets 40 adjacent to each other in the stacking direction and bonded by the bonding portion 41 are not bonded to each other entirely. These electromagnetic steel sheets 40 are bonded to each other partially.

[0088] In this embodiment, adjacent electromagnetic steel sheets 40 in the stacking direction are bonded together via bonding portions 41 provided along the periphery of the electromagnetic steel sheets 40. Specifically, adjacent electromagnetic steel sheets 40 in the stacking direction are bonded together via first bonding portions 41a and second bonding portions 41b. When viewed from above as the electromagnetic steel sheets 40 are stacked, the first bonding portions 41a are provided along the outer periphery of the electromagnetic steel sheets 40. When viewed from above as the electromagnetic steel sheets 40 are stacked, the second bonding portions 41b are provided along the inner periphery of the electromagnetic steel sheets 40. Furthermore, the first and second bonding portions 41a and 41b are each formed into a strip shape when viewed from above.

[0089] Here, the term "band-shaped" also includes shapes where the width of the band changes along the way. For example, a shape where circular points continue in one direction without interruption is also included in a band-shaped shape extending in one direction. Furthermore, "along the periphery" includes not only shapes that are completely parallel to the periphery but also shapes that are inclined, for example, within 5 degrees relative to the periphery.

[0090] The first bonding portion 41a is arranged along the outer peripheral edge of the electromagnetic steel sheet 40. The first bonding portion 41a extends continuously over the entire circumference. The first bonding portion 41a is formed in an annular shape in a plan view when viewed from the stacking direction.

[0091] The second bonding portion 41b is arranged along the inner peripheral edge of the electromagnetic steel sheet 40. The second bonding portion 41b extends continuously over the entire circumference.

[0092] The second bonding portion 41b includes a plurality of teeth 44 and a plurality of core backs 45. The plurality of teeth 44 are spaced apart in the circumferential direction and are disposed on each tooth 23. The plurality of core backs 45 are disposed on the core back 22 and connect the circumferentially adjacent teeth 44.

[0093] The tooth portion 44 includes a pair of first portions 44a and a second portion 44b. The first portions 44a are spaced apart in the circumferential direction. The first portions 44a extend radially. The first portions 44a extend radially in a band-like manner. The second portion 44b circumferentially connects the pair of first portions 44a. The second portion 44b extends circumferentially in a band-like manner.

[0094] In this embodiment, the top-view shapes of all bonding portions 41 provided between the electromagnetic steel sheets 40 are identical. The top-view shape of the bonding portion 41 refers to the overall shape of the bonding portion 41 when viewed from the stacking direction. The top-view shape of all bonding portions 41 provided between the electromagnetic steel sheets 40 includes not only the case where the top-view shapes of all bonding portions 41 provided between the electromagnetic steel sheets 40 are completely identical, but also includes the case where the bonding portions 41 provided between the electromagnetic steel sheets 40 are substantially identical. Substantially identical means that at least 95% of the top-view shapes of all bonding portions 41 provided between the electromagnetic steel sheets 40 are identical.

[0095] Furthermore, in this embodiment, the bonding area ratio of the bonding portion 41 to the electromagnetic steel sheet 40 is greater than 1% and less than 40%. In the illustrated example, the bonding area ratio is greater than 1% and less than 20%, specifically, 20%. Furthermore, the bonding area ratio of the bonding portion 41 to the electromagnetic steel sheet 40 refers to the ratio of the area of the region on the first surface where the bonding portion 41 is provided (bonding region 42) to the area of the surface of the electromagnetic steel sheet 40 facing the stacking direction (hereinafter referred to as the first surface of the electromagnetic steel sheet 40). The region where the bonding portion 41 is provided is the region on the first surface of the electromagnetic steel sheet 40 where the adhesive is provided without being divided (bonding region 42). The area of the region where the bonding portion 41 is provided is obtained, for example, by photographing the first surface of the electromagnetic steel sheet 40 after peeling and performing image analysis on the photographed result.

[0096] In this embodiment, the bonding area ratio of the bonding portion 41 between the electromagnetic steel sheets 40 is 1% or more and 20% or less. For each pair of adjacent electromagnetic steel sheets 40 in the stacking direction, the bonding area ratio of the bonding portion 41 to the electromagnetic steel sheets 40 is 1% or more and 20% or less. When bonding portions 41 are provided on both sides of a single electromagnetic steel sheet 40 in the stacking direction, the bonding area ratio on both surfaces of the electromagnetic steel sheet 40 is 1% or more and 20% or less.

[0097] Furthermore, compared to the case of caulking the electromagnetic steel sheets 40 , by bonding the electromagnetic steel sheets 40 with the bonding portions 41 , it is possible to easily secure a bonding area (joining area).

[0098] In this embodiment, the mutually caulked electromagnetic steel sheets 40 (N1 and N2 electromagnetic steel sheets 40, the first stack 76, and the second stack 77) are not bonded. In other words, no bonding portion 41 is provided between the mutually caulked electromagnetic steel sheets 40.

[0099] Furthermore, in this embodiment, the bonded electromagnetic steel sheets 40 (N3 sheets 40) are not caulked. In other words, the protrusions C11 and recesses C12 (or through-holes C13) of the bonded electromagnetic steel sheets 40 do not engage. In other words, at least the engagement of the protrusions C11 and recesses C12 (or through-holes C13) does not restrict relative displacement of the bonded electromagnetic steel sheets 40.

[0100] Furthermore, in this embodiment, the rivets C1 and C2 are positioned relative to the adhesive portion 41, avoiding each other when viewed from above. The rivets C1 and C2 are positioned offset from the adhesive portion 41 when viewed from above. The total area of the rivets C1 and C2 when viewed from above is smaller than the total area of the adhesive portion 41.

[0101] Here, the joining method at the boundary (hereinafter referred to as first boundary B1) between the N1 electromagnetic steel sheets 40 on the first side D1 joined by caulking and the N3 electromagnetic steel sheets 40 in the center joined by bonding can be caulking or bonding. In other words, the electromagnetic steel sheet 40 located closest to the second side D2 among the N1 electromagnetic steel sheets 40 on the first side D1 and the electromagnetic steel sheet 40 located closest to the first side D1 among the N3 electromagnetic steel sheets 40 in the center can be joined by caulking or bonding.

[0102] Furthermore, the boundary (hereinafter referred to as second boundary B2) between the N2 electromagnetic steel sheets 40 on the second side D2, which are joined by caulking, and the N3 electromagnetic steel sheets 40 in the center, which are joined by bonding, can be joined by caulking or bonding. In other words, the electromagnetic steel sheet 40 closest to the first side D1 among the N2 electromagnetic steel sheets 40 on the second side D2 and the electromagnetic steel sheet 40 closest to the second side D2 among the N3 electromagnetic steel sheets 40 in the center can be joined by caulking or bonding.

[0103] exist Figure 6 The stator core 21 and Figure 7 The stator core 21A shown, Figure 8 In the illustrated stator core 21B, electromagnetic steel sheets 40 adjacent to each other at both the first boundary B1 and the second boundary B2 are bonded together.

[0104] Here, one of the electromagnetic steel sheets 40 adjacent to each other at each of the first boundary B1 and the second boundary B2 is referred to as the third electromagnetic steel sheet 40, and the other is referred to as the fourth electromagnetic steel sheet 40. The third electromagnetic steel sheet 40 has a protrusion C11, a recess C12, or a through-hole C13 formed on the surface (first surface) facing the fourth electromagnetic steel sheet 40. The fourth electromagnetic steel sheet 40 has no protrusion C11, recess C12, or through-hole C13 formed on the surface (first surface) facing the third electromagnetic steel sheet 40. The surface of the fourth electromagnetic steel sheet 40 is substantially flat. The term "substantially flat" herein includes, for example, the case where the surface of the electromagnetic steel sheet 40 has irregularities that are unavoidably generated during manufacturing.

[0105] It is advantageous to basically join the electromagnetic steel sheets 40 at either the first boundary B1 or the second boundary B2. However, the electromagnetic steel sheets 40 may not be joined at either boundary B1 or B2 in anticipation of the fastening force due to the windings.

[0106] Compared to bonding, riveting can improve dimensional accuracy. Here, among the multiple electromagnetic steel sheets 40, the electromagnetic steel sheets 40 located on the first side D1 along the stacking direction (the electromagnetic steel sheets 40 of the N1 sheet, the first stack 76) and the electromagnetic steel sheets 40 located on the second side D2 along the stacking direction (the electromagnetic steel sheets 40 of the N2 sheet, the second stack 77) are riveted together. Consequently, the shape accuracy of the portions of the stator core 21 located on the first side D1 and second side D2 in the stacking direction (portions located outward in the stacking direction relative to the center) can be improved. These portions have a greater impact on the outer shape of the stator core 21 than the portion located in the center of the stator core 21. Therefore, by improving the shape accuracy of these portions, the outer shape accuracy of the stator core 21 can be improved. Consequently, the stator core 21's ease of handling can be ensured. For example, even when windings are wound around the stator core 21, they can be wound with high precision.

[0107] In this embodiment, the aforementioned processability is significantly enhanced when the winding is passed through the slots between circumferentially adjacent teeth 23. Specifically, by improving the slot dimensional accuracy, the winding can be easily wound around the teeth 23 as designed. This increases the winding space factor within the slots, and consequently, improves the electrical load within the slots.

[0108] Compared to riveting, bonding can suppress strain in the electromagnetic steel sheets 40. Strain in the electromagnetic steel sheets 40 affects the iron loss of the electromagnetic steel sheets 40 and the magnetic properties of the stator core 21, so it is preferably kept small. Here, among the multiple electromagnetic steel sheets 40, the electromagnetic steel sheets 40 located in the center along the stacking direction (the N3 sheets 40 and the third stack 78) are bonded together. Therefore, compared to riveting these electromagnetic steel sheets 40, the generation of strain can be suppressed. As a result, the magnetic properties of the stator core 21 can be improved.

[0109] like Figure 3 As shown, N3 is greater than N1 and N2. Therefore, the ratio of the number of electromagnetic steel sheets 40 joined by caulking can be reduced in the entire stator core 21. As a result, the magnetic properties of the stator core 21 can be further improved.

[0110] N1 and N2 are equal. Therefore, in the stator core 21, a difference in dimensional accuracy between the first side D1 and the second side D2 in the lamination direction can be suppressed. This further ensures the handleability of the stator core 21.

[0111] In addition, the technical scope of the present invention is not limited to the above-mentioned embodiment, and various changes can be made within the scope not departing from the spirit of the present invention.

[0112] In the above embodiment, the caulking members C1 and C2 and the adhesive portion 41 are arranged at positions avoiding each other without overlapping in a plan view. However, the caulking members C1 and C2 and the adhesive portion 41 may overlap in a plan view.

[0113] The shape of the stator core is not limited to that shown in the above embodiment. Specifically, the stator core's outer and inner diameters, lamination thickness, number of slots, the ratio of the circumferential and radial dimensions of the teeth 23, and the radial dimension ratio of the teeth 23 to the core back 22 can be arbitrarily designed based on the desired characteristics of the rotating electrical machine.

[0114] In the rotor of the above embodiment, a set of two permanent magnets 32 forms one magnetic pole, but the present invention is not limited thereto. For example, one permanent magnet 32 may form one magnetic pole, or three or more permanent magnets 32 may form one magnetic pole.

[0115] In the above embodiment, a permanent magnet field type motor is described as an example of a rotating electrical machine. However, the structure of the rotating electrical machine is shown in the following example but is not limited thereto. Various known structures not shown below may be employed.

[0116] In the above embodiment, a permanent magnet field type motor is used as an example of a synchronous motor, but the present invention is not limited thereto. For example, the rotating electrical machine may be a reluctance motor or an electromagnetic field type motor (winding field type motor).

[0117] In the above embodiment, a synchronous motor is described as an example of an AC motor, but the present invention is not limited thereto. For example, the rotating electrical machine may be an induction motor.

[0118] In the above embodiment, an AC motor is described as an example of an electric motor, but the present invention is not limited thereto. For example, the rotating electrical machine may be a DC motor.

[0119] In the above embodiment, an electric motor is used as an example of a rotating electrical machine, but the present invention is not limited thereto. For example, the rotating electrical machine may be a generator.

[0120] In the above-described embodiment, the case where the laminated core of the present invention is applied to a stator core is exemplified, but it can also be applied to a rotor core.

[0121] Furthermore, within the scope not departing from the spirit of the present invention, components in the above-described embodiments may be appropriately replaced with known components, and the above-described modifications may be appropriately combined.

[0122] Next, a verification test was conducted to verify the aforementioned effects. This verification test was conducted by simulation using software. The software used was JMAG, a finite element method electromagnetic field analysis software manufactured by JSOL Corporation.

[0123] As verification tests, a first verification test and a second verification test were performed.

[0124] (First verification test)

[0125] In the first verification test, the operational effect was verified for a case where the electromagnetic steel sheets on both sides in the lamination direction were caulked and the electromagnetic steel sheet in the center was bonded.

[0126] In this verification test, simulations were performed on the stators of Comparative Examples 1 and 2 and the stator of Example 1.

[0127] The stators of Comparative Examples 1 and 2 and the stator of Example 1 are the same: Figures 1 to 6 The stator 20 of the embodiment shown has the following modifications as a basic structure: the thickness of the electromagnetic steel sheet is set to 0.25 mm, the lamination thickness of the laminated core is set to 50 mm, and the number of electromagnetic steel sheets is set to 200.

[0128] In addition, in the stator of Comparative Example 1, all 200 electromagnetic steel sheets were joined by caulking. In the stator of Comparative Example 2, all 200 electromagnetic steel sheets were joined by bonding. In the stator of Example 1, every 30 sheets (15% of the total number of sheets) on both sides of the stacking direction of the 200 electromagnetic steel sheets were joined by caulking, and the 140 sheets (70% of the total number of sheets) located in the center of the stacking direction were joined by bonding.

[0129] For each stator in Comparative Examples 1 and 2, and Example 1, the iron loss per electromagnetic steel sheet and the dimensional accuracy of the stator core were determined. The iron loss was calculated through simulation using the aforementioned software. Regarding dimensional accuracy, the deviation from the expected dimensions was evaluated when manufacturing five stator cores for each example.

[0130] The results are shown in Table 1 below.

[0131] [Table 1]

[0132] Comparative Example 1 Example 1 Comparative Example 2 Joining method All layers riveted Riveted on both sides and bonded in the center All bonding Iron loss (w / kg) 27.4 25.0 24.0 Dimensional accuracy excellent good bad

[0133] As described above, in Example 1, an improvement of 8.8% (= (27.4 - 25.0) / 27.4) in iron loss was observed compared to Comparative Example 1, and good results were also obtained regarding dimensional accuracy.

[0134] (Second verification test)

[0135] In the second verification test, the difference in effect was verified based on the difference in the number of riveted sheets and the number of bonded sheets.

[0136] In this verification test, simulations were performed on the stators of Examples 11 to 14.

[0137] The stators of Examples 11 to 14 are all the same: Figures 1 to 6 The stator 20 of the embodiment shown has the following modifications as a basic structure: the thickness of the electromagnetic steel sheet is set to 0.25 mm, the lamination thickness of the laminated core is set to 50 mm, and the number of electromagnetic steel sheets is set to 200.

[0138] On this basis, the stators of Examples 11 to 14 were set as follows.

[0139] In the stator of Example 11, 20 electromagnetic steel sheets (10% of the total number of sheets) located on both sides of the stacking direction are joined by caulking, and 160 sheets (80% of the total number of sheets) located in the center of the stacking direction are joined by bonding.

[0140] In the stator of Example 12, 40 electromagnetic steel sheets (20% of the total number of sheets) located on both sides of the stacking direction out of 200 sheets are joined by caulking, and 120 sheets (60% of the total number of sheets) located in the center of the stacking direction are joined by bonding.

[0141] In the stator of Example 13, 60 electromagnetic steel sheets (30% of the total number of sheets) located on both sides of the stacking direction out of 200 sheets are joined by caulking, and 80 sheets (40% of the total number of sheets) located in the center of the stacking direction are joined by bonding.

[0142] In the stator of Example 14, 80 electromagnetic steel sheets (40% of the total number of sheets) located on both sides of the stacking direction out of 200 sheets are joined by caulking, and 40 sheets (20% of the total number of sheets) located in the center of the stacking direction are joined by bonding.

[0143] The results are shown in Table 2 below.

[0144] [Table 2]

[0145] Example 11 Example 12 Example 13 Example 14 Riveting ratio (one side) 10％ 20％ 30％ 40％ Bonding ratio 80％ 60％ 40％ 20％ Iron loss (w / kg) 24.7 25.4 26.0 26.7 Dimensional accuracy Can good good good

[0146] The above results confirm that iron loss improves in the order from Example 14 to Example 11. For example, compared to Example 14, an iron loss improvement of 7.5% (= (26.7 - 24.7) / 26.7) was observed in Example 11. Compared to Example 14, an iron loss improvement of 4.9% (= (26.7 - 25.4) / 26.7) was observed in Example 12.

[0147] On the other hand, in Examples 12 to 14, good results were obtained in terms of dimensional accuracy.

[0148] These results confirm that the number N1 of electromagnetic steel sheets riveted to each other (first laminate) located on the first side in the stacking direction, the number N2 of electromagnetic steel sheets riveted to each other (second laminate) located on the second side in the stacking direction, and the total number N0 of electromagnetic steel sheets preferably satisfy the following relationship. Specifically, it was confirmed that N1 and N2 are equal (N1 = N2), and that the ratios of N1 and N2 to N0 (N1 / N0 and N2 / N0) are preferably 10% or more and 40% or less. Furthermore, it was confirmed that these ratios are more preferably 20% or more and 40% or less.

[0149] [Industrial Applicability]

[0150] According to the present invention, it is possible to ensure dimensional accuracy of the outer shape and improve magnetic properties, and therefore has great industrial applicability.

[0151] [Explanation of Reference Numerals]

[0152] 10 Rotating motor

[0153] 21, 21A, 21B stator core (laminated core)

[0154] 22 Core back

[0155] 23 teeth

[0156] 40 electromagnetic steel plate

Claims

1. A laminated iron core comprising a plurality of electromagnetic steel sheets laminated on each other. The electromagnetic steel sheets located on the first side along the stacking direction and the electromagnetic steel sheets located on the second side along the stacking direction among the plurality of electromagnetic steel sheets are riveted to each other without being bonded, and the electromagnetic steel sheets located in the center along the stacking direction are bonded to each other via bonding portions formed of a room temperature curing adhesive without being riveted. The electromagnetic steel plate comprises: Ring-shaped core back; and a plurality of teeth protruding from the core back in the radial direction of the core back and arranged at intervals in the circumferential direction of the core back, The plates constituting the laminated core are all electromagnetic steel plates. A bonding portion composed of an adhesive is provided on the bonded electromagnetic steel sheets, and a bonding area ratio formed by the bonding portion is not less than 1% and not more than 40%. A rivet is provided on the riveted electromagnetic steel plate. The rivet and the bonding portion are arranged at positions that do not overlap and avoid each other when viewed from above. The laminated iron core is a non-dividable laminated iron core.

2. The laminated core according to claim 1, The electromagnetic steel sheet is not divided in the circumferential direction.

3. The laminated core according to claim 1, The outer diameters of the annular core backs of the electromagnetic steel sheet located on the first side, the electromagnetic steel sheet located on the second side, and the electromagnetic steel sheet located in the center are the same.

4. The laminated core according to claim 1, The number of the electromagnetic steel sheets located at the center and bonded to each other is greater than the number of the electromagnetic steel sheets located at the first side and riveted to each other and the number of the electromagnetic steel sheets located at the second side and riveted to each other.

5. The laminated iron core according to any one of claims 1 to 4, The number of the electromagnetic steel plates located on the first side and riveted to each other is equal to the number of the electromagnetic steel plates located on the second side and riveted to each other.

6. The laminated iron core according to any one of claims 1 to 4, The average thickness of the bonding portion is 1.0 μm to 3.0 μm.

7. The laminated core according to any one of claims 1 to 4, The average tensile elastic modulus E of the bonding portion is 1500 MPa to 4500 MPa.

8. The laminated iron core according to any one of claims 1 to 4, The bonding portion is a room temperature adhesive acrylic adhesive comprising SGA, which is composed of an acrylic adhesive containing an elastomer. 9 . A rotating electrical machine comprising the laminated iron core according to claim 1 .

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