Core block, laminated core, rotating electric machine, and method for manufacturing core block

Abstract

Improves the magnetic properties of the laminated core. [Solution] The laminated core is a core block that is formed by connecting multiple pieces in a ring shape, and comprises multiple electromagnetic steel sheet pieces stacked on top of each other, and adhesive portions that are provided between adjacent electromagnetic steel sheet pieces in the stacking direction and that bond the electromagnetic steel sheet pieces together, and the adhesive area ratio of the electromagnetic steel sheet pieces by the adhesive portions is 1% or more and 60% or less.

Description

[Technical field]

[0001] The present invention relates to a core block, a laminated core, a rotating electric machine, and a method for manufacturing a core block. This application claims priority based on Japanese Patent Application No. 2019-118337, filed on June 26, 2019, the contents of which are incorporated herein by reference. [Background technology]

[0002] Conventionally, there is known a laminated core as described in the following Patent Document 1. In this laminated core, adjacent electromagnetic steel sheets in the lamination direction are bonded together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-023523 A Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional laminated cores have room for improvement in terms of improving their magnetic properties.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to improve the magnetic characteristics of a laminated core. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention proposes the following means. (1) A first aspect of the present invention is a core block that constitutes a laminated core by connecting a plurality of pieces in a ring shape, the core block comprising a plurality of electromagnetic steel sheet pieces stacked on each other, and adhesive portions provided between adjacent electromagnetic steel sheet pieces in the stacking direction and bonding the electromagnetic steel sheet pieces together, wherein the bonding area ratio of the electromagnetic steel sheet pieces by the adhesive portions is 1% or more and 60% or less.

[0007] If adjacent electromagnetic steel sheet pieces in the stacking direction are not fixed to each other by some means, they will be displaced relative to each other. On the other hand, if adjacent electromagnetic steel sheet pieces in the stacking direction are fixed to each other by, for example, crimping, plastic strain is applied to some of the electromagnetic steel sheet pieces, deteriorating the magnetic properties of the core block. In the core block having the above-mentioned configuration, adjacent electromagnetic steel sheet pieces in the stacking direction are bonded together by adhesive parts. Therefore, it is possible to suppress relative displacement between adjacent electromagnetic steel sheet pieces in the stacking direction in the entirety of the multiple electromagnetic steel sheet pieces. Since the adhesive area ratio of the adhesive parts provided on the electromagnetic steel sheet pieces is 1% or more, the adhesive parts ensure adhesion between the electromagnetic steel sheet pieces, and it is possible to effectively restrict relative displacement between adjacent electromagnetic steel sheet pieces in the stacking direction even during winding, etc. Furthermore, since the electromagnetic steel sheet pieces are fixed together by adhesive rather than by crimping as described above, it is possible to suppress distortion occurring in the electromagnetic steel sheet pieces. From the above, it is possible to ensure the magnetic properties of the core block. However, compressive stress occurs in the electromagnetic steel sheet pieces as the adhesive hardens. Therefore, there is a risk that the adhesive bonding at the adhesive may cause distortion in the electromagnetic steel sheet pieces. In the core block having the above-mentioned configuration, the adhesive bonding area ratio of the electromagnetic steel sheet pieces at the adhesive is 60% or less. Therefore, distortion in the electromagnetic steel sheet pieces caused by the adhesive can be kept low. This makes it possible to further ensure the magnetic properties of the core block.

[0008] (2) In the core block described in (1) above, the adhesion area ratio may be 1% or more and 20% or less. According to this configuration, the distortion caused in the electromagnetic steel sheet pieces by the adhesive joint can be further reduced.

[0009] (3) The core block described in (1) or (2) may have an arc-shaped core back portion and teeth portions protruding from the core back portion to one radial side of the core back portion, and the adhesive portion may have a pair of first portions extending along the circumferential edges of both sides of the teeth portions in the circumferential direction, a second portion extending along the circumferential edges of the tips of the teeth portions and connecting the tips of the pair of first portions, a pair of third portions extending from a base end of the first portions to both circumferential sides along the circumferential edge of one radial side of the core back portion, a fourth portion 45b extending in the circumferential direction along the circumferential edge of the other radial side of the core back portion, and a pair of fifth portions extending along the circumferential edges of both circumferential sides of the core back portion and connecting the third portion and the fourth portion, respectively.

[0010] (4) In the core block according to (3), the second portion and the fifth portion may have a width narrower than a width of the fourth portion.

[0011] (5) In the core block according to any one of (1) to (4), the adhesive portion may be provided on at least a part of a periphery of the electromagnetic steel sheet piece. By disposing the adhesive portion on the periphery of the electromagnetic steel sheet pieces, for example, it is possible to suppress curling of the electromagnetic steel sheet pieces, etc. This makes it easier to perform the winding process and further ensures the magnetic properties of the laminated core.

[0012] (6) In the core block described in any one of (1) to (4), a non-adhesive region of the electromagnetic steel sheet piece where the adhesive portion is not provided may be formed between the adhesive region of the electromagnetic steel sheet piece where the adhesive portion is provided and a periphery of the electromagnetic steel sheet piece. The electromagnetic steel sheet pieces forming the core block are manufactured by punching the electromagnetic steel sheet pieces as the base material. During the punching process, a strain caused by the punching process is applied from the periphery of the electromagnetic steel sheet pieces toward the inside of the electromagnetic steel sheet pieces to a width of a size equivalent to the sheet thickness of the electromagnetic steel sheet pieces. Since the periphery of the electromagnetic steel sheet pieces is work-hardened by the above-mentioned strain, deformation such as localized turning over of the periphery of the electromagnetic steel sheet pieces is unlikely to occur. Therefore, even if the periphery of the electromagnetic steel sheet pieces is not bonded, deformation of the electromagnetic steel sheet pieces is unlikely to occur. Therefore, even if a non-bonded region is formed on the periphery of the electromagnetic steel sheet pieces, deformation of the electromagnetic steel sheet pieces can be suppressed. And by forming the non-bonded region in this way, it is possible to suppress the application of unnecessary strain to the electromagnetic steel sheet pieces. Therefore, the magnetic properties of the core block can be further ensured.

[0013] (7) In the core block according to (6), a width of the non-bonded region may be configured to be 1 to 10 times the thickness of the electromagnetic steel sheet pieces.

[0014] (8) The core block described in (1) or (2) may have an arc-shaped core back portion and teeth portions protruding radially from the core back portion, and the electromagnetic steel sheet pieces may be configured such that non-bonded areas of the electromagnetic steel sheet pieces where the adhesive portion is not provided are formed at the tips of the teeth portions and at both circumferential ends of the core back portion. In the core block, the magnetic flux extends from the tip of the tooth portion in a diffused manner to both sides in the circumferential direction. Therefore, the magnetic flux is likely to concentrate at the tip of the tooth portion. Furthermore, the magnetic flux enters the adjacent core block from both circumferential ends of the core back portion. Therefore, the magnetic flux is likely to concentrate at both circumferential ends of the core back portion. If an adhesive region is provided in the region where the magnetic flux is concentrated, the increase in iron loss is likely to be significant. Therefore, if adhesive regions are provided at the tip of the tooth portion and both circumferential ends of the core back portion, the iron loss is likely to be large. According to the above-mentioned configuration, since the non-adhesive regions where no adhesive region is provided are located at the tip of the tooth portion and both circumferential ends of the core back portion, the adhesive regions can be positioned away from the region with high magnetic flux density, and the increase in iron loss can be suppressed.

[0015] (9) The core block described in (1) or (2) may have an arc-shaped core back portion and teeth portions protruding radially from the core back portion, and the bonding area of ​​the core back portion provided by the adhesive portion may be greater than or equal to the bonding area of ​​the teeth portions provided by the adhesive portion. When the width (circumferential size) of the teeth is narrower than the width (radial size) of the core-back, magnetic flux tends to concentrate in the teeth, increasing the magnetic flux density in the teeth. Therefore, when the adhesive applies strain to the electromagnetic steel sheet, the same amount of strain has a greater effect on the magnetic properties of the teeth than on the magnetic properties of the core-back. The bonding area of ​​the core back portion by the bonding part is equal to or larger than the bonding area of ​​the teeth portion by the bonding part, so that the bonding strength of the laminated core as a whole can be ensured in the core back portion while suppressing the influence of deterioration of magnetic properties due to distortion of the bonding part in the teeth portion.

[0016] (10) In the laminated core according to any one of (1) to (9), the adhesive zone may have an average thickness of 1.0 μm to 3.0 μm.

[0017] (11) In the laminated core according to any one of (1) to (10), the adhesive joint may have an average tensile modulus E of 1500 MPa to 4500 MPa.

[0018] (12) In the laminated core described in any one of (1) to (11), the adhesive portion may be an acrylic adhesive of room temperature bonding type containing SGA made of an elastomer-containing acrylic adhesive.

[0019] (13) A second aspect of the present invention is a laminated core formed by connecting a plurality of core blocks according to any one of (1) to (12) in an annular shape.

[0020] (14) A second aspect of the present invention is a rotating electric machine including the laminated core according to (13) above. Effect of the Invention

[0021] According to the present invention, the magnetic properties of the laminated core can be improved. [Brief description of the drawings]

[0022] [Figure 1] 1 is a plan view of a rotating electric machine according to an embodiment of the present invention; [Diagram 2] 2 is a side view of a core block included in the rotating electric machine shown in FIG. [Diagram 3] 2 is a plan view of a core block included in the rotating electric machine shown in FIG. [Figure 4] FIG. 11 is a plan view of a core block according to a first modified example. [Diagram 5] FIG. 11 is a plan view of a core block according to a second modified example. [Figure 6] FIG. 13 is a plan view of a core block of a third modified example. [Figure 7] FIG. 2 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 100%. [Figure 8] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 90%. [Figure 9] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 85%. [Figure 10] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 70%. [Figure 11] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 60%. [Figure 12] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 50%. [Figure 13]FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 40%. [Figure 14] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 30%. [Figure 15] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 20%. [Figure 16] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 15%. [Figure 17] FIG. 1 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 10%. [Figure 18] FIG. 2 is a plan view of a stator that was the subject of iron loss simulation in a verification test, showing a state in which the adhesive area ratio is 0%. [Figure 19] FIG. 2 is a plan view of a comparative stator core that was the subject of iron loss simulation in a verification test, showing a state in which electromagnetic steel sheets are joined by crimping. [Figure 20] 1 is a graph showing the results of a verification test. [Figure 21] FIG. 2 is a plan view of a stator used in a simulation of iron loss in a verification test. [Figure 22] FIG. 2 is a plan view of a stator used in a simulation of iron loss in a verification test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, a rotating electric machine according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the rotating electric machine will be described by taking an electric motor, specifically an AC electric motor, more specifically a synchronous electric motor, and even more specifically a permanent magnet field type electric motor, as an example. This type of electric motor is preferably used in, for example, electric vehicles.

[0024] 1, the rotating electric machine 10 includes a stator 20, a rotor 30, a case 50, and a rotating shaft 60. The stator 20 and the rotor 30 are housed in the case 50. The stator 20 is fixed to the case 50. In this embodiment, the rotating electric machine 10 is an inner rotor type in which the rotor 30 is located inside the stator 20. However, the rotating electric machine 10 may be an outer rotor type in which the rotor 30 is located outside the stator 20. In this embodiment, the rotating electric machine 10 is a three-phase AC motor with 12 poles and 18 slots. However, the number of poles, the number of slots, the number of phases, etc., can be changed as appropriate. Note that this rotating electric machine 10 can rotate at a rotation speed of 1000 rpm by applying an excitation current with an effective value of 10 A and a frequency of 100 Hz to each phase, for example.

[0025] The stator 20 includes a stator core (laminated core) 21, a fastening ring 29, and a winding (not shown). Hereinafter, the direction along the central axis O of the stator core 21 will be simply referred to as the axial direction, the direction passing through the central axis O of the stator core 21 and perpendicular to the central axis O will be simply referred to as the radial direction, and the direction going around the central axis O of the stator core 21 will be simply referred to as the circumferential direction. In addition, in this specification, the "radial inner side" may be referred to as "one radial side".

[0026] The rotor 30 is disposed radially inside the stator 20 (the stator core 21). The rotor 30 includes a rotor core 31 and a plurality of permanent magnets 32. The rotor core 31 is formed in an annular (circular) shape and is disposed coaxially with the stator 20. The rotating shaft 60 is disposed within the rotor core 31. The rotating shaft 60 is fixed to the rotor core 31. The multiple permanent magnets 32 are fixed to the rotor core 31. In this embodiment, a pair of the permanent magnets 32 forms one magnetic pole. The multiple pairs of permanent magnets 32 are arranged at equal intervals in the circumferential direction. In this embodiment, 12 pairs of permanent magnets 32 (total of 24 magnets) are provided at 30 degree intervals around the central axis O.

[0027] In this embodiment, an embedded magnet motor is used as the permanent magnet field type motor. A rotor core 31 is formed with a plurality of through holes 33 that pass through the rotor core 31 in the axial direction. The plurality of through holes 33 are provided corresponding to a plurality of permanent magnets 32. Each permanent magnet 32 ​​is fixed to the rotor core 31 while being disposed in the corresponding through hole 33. Each permanent magnet 32 ​​can be fixed to the rotor core 31 by, for example, bonding the outer surface of the permanent magnet 32 ​​to the inner surface of the through hole 33 with an adhesive. Note that a surface magnet motor may be used as the permanent magnet field type motor instead of the embedded magnet motor.

[0028] The rotor core 31 is a laminated core. That is, the rotor core 31 is formed by laminating a plurality of electromagnetic steel sheets. The lamination thickness of the rotor core 31 is, for example, 50.0 mm. The outer diameter of the rotor core 31 is, for example, 163.0 mm. The inner diameter of the rotor core 31 is, for example, 30.0 mm. In this embodiment, the multiple electromagnetic steel sheets forming rotor core 31 are fixed to one another by crimping C (dowels). However, the multiple electromagnetic steel sheets forming rotor core 31 may be bonded to one another.

[0029] Next, the stator core 21 will be described in more detail. The lamination thickness of the stator core 21 is, for example, 50.0 mm. The outer diameter of the stator core 21 is, for example, 250.0 mm. The inner diameter of the stator core 21 is, for example, 165.0 mm. Here, the inner diameter of the stator core 21 is based on the tips of the teeth portions 23 of the stator core 21. The inner diameter of the stator core 21 is the diameter of an imaginary circle inscribed in the tips of all of the teeth portions 23.

[0030] The stator core 21 is a split core. Thus, the stator core 21 has a plurality of core blocks 24. The plurality of core blocks 24 are connected together in an annular shape to form the stator core 21. A fastening ring 29 is disposed on the radial outside of the plurality of core blocks 24. The plurality of core blocks 24 are fixed to one another by being fitted into the fastening ring 29.

[0031] Next, the core block 24 will be described. The core block 24 has an arc-shaped core back portion 22 extending along the circumferential direction, and teeth portions 23. Fig. 1 illustrates a boundary line 24BL between the core back portion 22 and the teeth portions 23. The core block 24 has a pair of corner portions 24c provided between a surface facing radially inward and a surface facing the circumferential direction on the outer surface. The boundary line 24BL is an arc centered on the central axis O and passing through the pair of corner portions 24c.

[0032] The core back portion 22 is formed in an arc shape centered on the central axis O in a plan view of the stator 20 seen in the axial direction. The teeth portions 23 protrude radially inward from the core back portion 22 (toward the central axis O of the core back portion 22 along the radial direction). A plurality of core blocks 24 are arranged in an annular shape along the circumferential direction to form the stator core 21, and the teeth portions 23 are arranged at equal intervals in the circumferential direction. The stator 20 of this embodiment is provided with 18 teeth portions 23 spaced at 20 degree intervals around the central axis O. The teeth portions 23 are formed to have the same shape and size as one another. The winding is wound around the teeth portion 23. The winding may be a concentrated winding or a distributed winding.

[0033] Core block 24 is configured by stacking multiple electromagnetic steel sheet pieces 40, which are formed by punching electromagnetic steel sheets, in the axial direction. That is, core block 24 has multiple electromagnetic steel sheet pieces 40 stacked on top of each other. Therefore, stator core 21 is a laminated core. Each of the multiple electromagnetic steel sheet pieces 40 is T-shaped when viewed in the axial direction.

[0034] Each electromagnetic steel sheet piece 40 forming the core block 24 is formed, for example, by punching an electromagnetic steel sheet as a base material. A known electromagnetic steel sheet can be used as the electromagnetic steel sheet piece 40. The chemical composition of the electromagnetic steel sheet piece 40 is not particularly limited. In this embodiment, a non-oriented electromagnetic steel sheet is used as the electromagnetic steel sheet piece 40. For example, a non-oriented electrical steel strip of JIS C 2552:2014 can be used as the non-oriented electromagnetic steel sheet. However, it is also possible to use a directional electromagnetic steel sheet as the electromagnetic steel sheet piece 40 instead of the non-oriented electromagnetic steel sheet. For example, a directional electrical steel strip of JIS C 2553:2012 can be used as the directional electromagnetic steel sheet.

[0035] In order to improve the workability of the electromagnetic steel sheet pieces 40 and the iron loss of the core block 24, an insulating coating is provided on both sides of the electromagnetic steel sheet pieces 40. Examples of the material that can be used to form the insulating coating include (1) inorganic compounds, (2) organic resins, and (3) mixtures of inorganic compounds and organic resins. Examples of inorganic compounds include (1) composites of dichromate and boric acid, and (2) composites of phosphate and silica. Examples of organic resins include epoxy resins, acrylic resins, acrylic styrene resins, polyester resins, silicone resins, and fluorine resins.

[0036] In order to ensure the insulating performance between the stacked magnetic steel sheet pieces 40, the thickness of the insulating coating (the thickness per side of the magnetic steel sheet pieces 40) is preferably 0.1 μm or more. On the other hand, as the insulating coating becomes thicker, the insulating effect saturates. Also, as the insulating coating becomes thicker, the proportion of the core block 24 that it occupies increases, the magnetic properties of the core block 24 deteriorate, and the performance as a laminated core deteriorates. Therefore, it is preferable that the insulating coating is thin as long as the insulating performance can be ensured. The thickness of the insulating coating (thickness per side of the electromagnetic steel sheet piece 40) is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 2 μm or less.

[0037] As the magnetic steel sheet pieces 40 become thinner, the iron loss improvement effect gradually saturates. Furthermore, as the magnetic steel sheet pieces 40 become thinner, the manufacturing costs of the magnetic steel sheet pieces 40 increase. Therefore, in consideration of the iron loss improvement effect and manufacturing costs, it is preferable that the thickness of the magnetic steel sheet pieces 40 be 0.10 mm or more. On the other hand, if the electromagnetic steel sheet pieces 40 are too thick, it becomes difficult to perform the press punching operation on the electromagnetic steel sheet pieces 40. Therefore, taking into consideration the press punching operation on the electromagnetic steel sheet pieces 40, it is preferable that the thickness of the electromagnetic steel sheet pieces 40 be 0.65 mm or less. Furthermore, the iron loss increases as the thickness of the electromagnetic steel pieces 40 increases. Therefore, in consideration of the iron loss characteristics of the electromagnetic steel pieces 40, the thickness of the electromagnetic steel pieces 40 is preferably 0.35 mm or less, and more preferably 0.20 mm or 0.25 mm. Considering the above, the thickness of each electromagnetic steel sheet piece 40 is, for example, 0.10 mm to 0.65 mm, preferably 0.10 mm to 0.35 mm, and more preferably 0.20 mm or 0.25 mm. The thickness of the electromagnetic steel sheet piece 40 includes the thickness of the insulating coating.

[0038] The multiple electromagnetic steel sheet pieces 40 forming the core block 24 are bonded by adhesive parts 41. The adhesive parts 41 are provided between the electromagnetic steel sheet pieces 40 adjacent to each other in the stacking direction, and are hardened without being separated. For example, a thermosetting adhesive by polymerization bonding is used. As the adhesive composition, (1) acrylic resin, (2) epoxy resin, (3) a composition containing an acrylic resin and an epoxy resin, etc. can be applied. As such an adhesive, in addition to a thermosetting adhesive, a radical polymerization adhesive, etc. can be used, and from the viewpoint of productivity, it is desirable to use a room temperature curing adhesive. The room temperature curing adhesive cures at 20°C to 30°C. As the room temperature curing adhesive, an acrylic adhesive is preferable. A typical acrylic adhesive is SGA (Second Generation Acrylic Adhesive). Anaerobic adhesives, instant adhesives, and elastomer-containing acrylic adhesives can all be used within a range that does not impair the effects of the present invention. The adhesive referred to here is in a state before it hardens, and becomes adhesive portion 41 after the adhesive hardens.

[0039] The average tensile modulus E of the adhesive portion 41 at room temperature (20°C to 30°C) is set to be 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, a problem occurs in which the rigidity of the laminated core decreases. Therefore, the lower limit of the average tensile modulus E of the adhesive portion 41 is set to 1500 MPa, more preferably 1800 MPa. Conversely, if the average tensile modulus E of the adhesive portion 41 exceeds 4500 MPa, a problem occurs in which the insulating coating formed on the surface of the electromagnetic steel sheet piece 40 peels off. Therefore, the upper limit of the average tensile modulus E of the adhesive portion 41 is set to 4500 MPa, more preferably 3650 MPa. The average tensile elastic modulus E is measured by a resonance method. Specifically, the tensile elastic modulus is measured in accordance with JIS R 1602:1995. More specifically, first, a sample for measurement (not shown) is produced. This sample is obtained by bonding two electromagnetic steel sheet pieces 40 together with the adhesive to be measured, and then curing the adhesive to form an adhesive joint 41. If the adhesive is a thermosetting type, this curing is performed by heating and pressing under heating and pressing conditions for actual operation. On the other hand, if the adhesive is a room temperature curing type, this is performed by pressing at room temperature. The tensile modulus of elasticity of this sample is then measured by a resonance method. The method for measuring the tensile modulus of elasticity by the resonance method is performed in accordance with JIS R 1602:1995, as described above. The tensile modulus of elasticity of the adhesive portion 41 alone is then found by subtracting the influence of the electromagnetic steel sheet piece 40 itself from the tensile modulus of elasticity (measured value) of the sample through calculation. The tensile modulus thus determined from the samples is equal to the average value for the entire laminated core, and this value is regarded as the average tensile modulus E. The composition is set so that the average tensile modulus E varies little with the lamination position along the lamination direction and the circumferential position around the central axis of the laminated core. Therefore, the average tensile modulus E can also be determined by measuring the adhesive part 41 after curing at the upper end of the laminated core.

[0040] As a bonding method, for example, a method can be used in which an adhesive is applied to the electromagnetic steel sheet pieces 40, and then the pieces are bonded by either or both of heating and pressure bonding. Note that any heating means may be used, such as heating in a high-temperature tank or electric furnace, or directly passing electricity through the pieces.

[0041] In order to obtain a stable and sufficient adhesive strength, the thickness of the adhesive portion 41 is preferably 1 μm or more. On the other hand, when the thickness of adhesive portion 41 exceeds 100 μm, the adhesive strength becomes saturated. Also, as adhesive portion 41 becomes thicker, the proportion of adhesive portion in core block 24 increases, and magnetic properties such as core loss of core block 24 decrease. Therefore, the thickness of adhesive portion 41 is preferably set to 1 μm or more and 100 μm or less, more preferably 1 μm or more and 10 μm or less. In the above, the thickness of the adhesive portion 41 means the average thickness of the adhesive portion 41 .

[0042] It is more preferable that the average thickness of the adhesive portion 41 is 1.0 μm or more and 3.0 μm or less. If the average thickness of the adhesive portion 41 is less than 1.0 μm, sufficient adhesive strength cannot be ensured as described above. Therefore, the lower limit of the average thickness of the adhesive portion 41 is set to 1.0 μm, more preferably 1.2 μm. Conversely, if the average thickness of the adhesive portion 41 exceeds 3.0 μm and becomes too thick, problems such as a significant increase in the amount of distortion of the electromagnetic steel sheet pieces 40 due to shrinkage during thermal curing occur. Therefore, the upper limit of the average thickness of the adhesive portion 41 is set to 3.0 μm, more preferably 2.6 μm. The average thickness of the adhesive portion 41 is the average value for the entire laminated core. The average thickness of the adhesive portion 41 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 average thickness of the adhesive portion 41 can be determined by averaging values ​​measured at 10 or more points in the circumferential direction at the upper end position of the laminated core.

[0043] The average thickness of the adhesive 41 can be adjusted, for example, by changing the amount of adhesive applied. Also, the average tensile modulus E of the adhesive 41 can be adjusted, for example, in the case of a thermosetting adhesive, by changing one or both of the heating and pressurizing conditions and the type of curing agent applied during adhesion.

[0044] 2, in this embodiment, adjacent electromagnetic steel sheet pieces 40 in the stacking direction are bonded to each other by adhesive portions 41. In the illustrated example, adjacent electromagnetic steel sheet pieces 40 in the stacking direction are fixed to each other only by adhesion, and are not fixed to each other by other means (for example, crimping, etc.).

[0045] In Fig. 3, the adhesive portion 41 is highlighted with a dot pattern. As shown in Fig. 3, adjacent electromagnetic steel sheet pieces 40 in the stacking direction are not entirely adhered to each other. These electromagnetic steel sheet pieces 40 are locally adhered to each other.

[0046] In this embodiment, adjacent electromagnetic steel sheet pieces 40 in the stacking direction are bonded to each other by adhesive portions 41 provided on the periphery of the electromagnetic steel sheet pieces 40. According to this embodiment, the adhesive portions 41 are provided on the entire periphery of the electromagnetic steel sheet pieces 40. However, it is sufficient that the adhesive portions 41 are provided on at least a portion of the periphery of the electromagnetic steel sheet pieces 40.

[0047] The adhesive portions 41 are each formed in a band shape in a plan view. Here, the band shape includes a shape in which the width of the band changes midway. For example, a shape in which circular dots continue in one direction without being interrupted is also included in the band shape extending in one direction. In addition, being along the periphery of the electromagnetic steel sheet pieces 40 includes not only the case where it is completely parallel to the periphery, but also the case where it is inclined, for example, by 5 degrees or less with respect to the periphery.

[0048] The bonding portion 41 has a tooth portion 44 arranged in the tooth portion 23, and a core back portion 45 arranged in the core back portion 22. The tooth portion 44 of the bonding portion 41 has a pair of first portions 44a and a second portion 44b. The core back portion 45 of the bonding portion 41 has a pair of third portions 45a, a fourth portion 45b, and a pair of fifth portions 45c. That is, the bonding portion 41 has a pair of first portions 44a, a second portion 44b, a pair of third portions 45a, a fourth portion 45b, and a pair of fifth portions 45c.

[0049] The pair of first portions 44a extend along the circumferential edges of both sides of the teeth portion 23. The pair of first portions 44a are arranged with a gap therebetween in the circumferential direction. The second portion 44b extends along the circumferential edges of the tips of the teeth portion 23 and connects the tips of the pair of first portions 44a. The pair of third portions extend from the base end of the first portion 44a along the circumferential edges of the inner side (one side in the radial direction) of the core back portion 22 on both sides in the circumferential direction. The fourth portion 45b extends in the circumferential direction along the circumferential edges of the outer side (the other side in the radial direction) of the core back portion 22. The pair of fifth portions 45c extend along the circumferential edges of the core back portion 22 on both sides in the circumferential direction and connect the third portion 45a and the fourth portion 45b, respectively.

[0050] According to this embodiment, the first portion 44a, the second portion 44b, the third portion 45a, the fourth portion 45b, and the fifth portion 45c of the adhesive portion 41 are each formed to border the periphery that constitutes the outer shape of the electromagnetic steel sheet pieces 40. This makes it possible to firmly hold the stacked electromagnetic steel sheet pieces 40 together in the vicinity of the periphery of the adhesive portion 41. As a result, it is possible to effectively suppress curling that is likely to occur near the periphery of the electromagnetic steel sheet pieces 40, and it is possible to achieve strong fixation of the electromagnetic steel sheet pieces 40 together while reducing the adhesive area ratio.

[0051] In the present embodiment, the adhesive portion 41 is provided without a gap from the periphery of the electromagnetic steel sheet piece 40 in a plan view of the electromagnetic steel sheet piece 40, but the present invention is not limited to this. For example, as in a core block 124 according to a first modified example shown in FIG. 4, the adhesive portion 141 may be provided with a gap from the periphery of the electromagnetic steel sheet piece 40 in a plan view of the electromagnetic steel sheet piece 40. That is, a non-adhesive region 143 of the electromagnetic steel sheet piece 40 where the adhesive portion 141 is not provided may be formed between the adhesive region 142 of the electromagnetic steel sheet piece 40 where the adhesive portion 141 is provided and the periphery of the electromagnetic steel sheet piece 40. The adhesive region 142 of the electromagnetic steel sheet piece 40 where the adhesive portion 141 is provided means a region where the hardened adhesive is provided without being divided among the surface of the electromagnetic steel sheet piece 40 facing the stacking direction (hereinafter referred to as the first surface of the electromagnetic steel sheet piece 40). The non-bonded region 143 of the electromagnetic steel sheet piece 40 where no adhesive portion 141 is provided means a region of the first surface of the electromagnetic steel sheet piece 40 where no hardened adhesive is provided without being divided.

[0052] 5 according to a second modified example, the adhesive portion 241 may be configured not to have portions corresponding to the second portion 44b and the fifth portion 45c in the adhesive portion 41 of the above-described embodiment. That is, in the electromagnetic steel sheet pieces 40, non-adhesive regions 243 in which the adhesive portion 241 is not provided may be formed at the tips of the teeth portions 23 and at both circumferential ends of the core back portion 22. In this modified example, the adhesive portion 241 has a pair of first portions 244a arranged at intervals in the circumferential direction in the teeth portions 23 and extending along the radial direction, a pair of third portions 245a extending along the radial inner edge of the core back portion 22, and a fourth portion 245b extending along the radial outer edge of the core back portion 22.

[0053] Furthermore, as in the core block 324 according to the third modification shown in FIG. 6, the width dimensions of each portion of the adhesive portion 341 may be configured differently from those of the above-mentioned embodiment. The adhesive portion 341 of the third modification has a pair of first portions 344a, a second portion 344b, a pair of third portions 345a, a fourth portion 345b, and a pair of fifth portions 345c, as in the above-mentioned embodiment. In this modification, the widths of the first portion 344a, the second portion 344b, the third portion 345a, and the fifth portion 345c are approximately equal. On the other hand, the width of the fourth portion 345b is wider than the widths of the other portions (the first portion 344a, the second portion 344b, the third portion 345a, and the fifth portion 345c) of the adhesive portion 341.

[0054] In this specification, the "width" of each portion of the adhesive portion 341 means the dimension in a direction perpendicular to the direction in which the portion extends. For example, the widths of the second portion 344b, the third portion 345a, and the fourth portion 345b are the dimensions along the radial direction of each portion. Moreover, the widths of the first portion 344a and the fifth portion 345c are the dimensions along the circumferential direction of each portion. In this specification, the width of each portion of adhesive portion 41 is 1.5% or more of the outer diameter of stator core 21. When the width of each portion of adhesive portion 41 is 1.5% or more of the outer diameter of stator core 21, the adhesive strength between the electromagnetic steel sheet pieces 40 can be sufficiently ensured.

[0055] 2, in this embodiment, all of the adhesive parts 41 provided between the electromagnetic steel pieces 40 have the same planar shape. The planar shape of the adhesive part 41 means the overall shape of the adhesive part 41 in a plan view when the electromagnetic steel piece 40 on which the adhesive part 41 is provided is seen from the stacking direction. All of the adhesive parts 41 provided between the electromagnetic steel pieces 40 having the same planar shape does not only include the case where all of the adhesive parts 41 provided between the electromagnetic steel pieces 40 have completely the same planar shape, but also includes the case where all of the adhesive parts 41 provided between the electromagnetic steel pieces 40 have substantially the same planar shape, that is, 95% or more of the planar shapes are the same.

[0056] In this embodiment, the adhesion area ratio of the electromagnetic steel sheet pieces 40 by the adhesion parts 41 is 1% or more and 60% or less. In the illustrated example, the adhesion area ratio is 1% or more and 20% or less, specifically 20%. The adhesion area ratio of the electromagnetic steel sheet pieces 40 by the adhesion parts 41 is the ratio of the area of ​​the region (adhesive region 42) on the first surface where the adhesion parts 41 are provided to the area of ​​the first surface of the electromagnetic steel sheet pieces 40. The region where the adhesion parts 41 are provided is the region (adhesive region 42) on the first surface of the electromagnetic steel sheet pieces 40 where the adhesive that has hardened is provided without being divided. The area of ​​the region where the adhesion parts 41 are provided can be found, for example, by photographing the first surface of the electromagnetic steel sheet pieces 40 after peeling and performing image analysis on the photographed result.

[0057] In this embodiment, the adhesion area ratio of the electromagnetic steel sheet pieces 40 by the adhesive parts 41 between the electromagnetic steel sheet pieces 40 is 1% or more and 20% or less. For both electromagnetic steel sheet pieces 40 adjacent in the stacking direction, the adhesion area ratio of the electromagnetic steel sheet pieces 40 by the adhesive parts 41 is both 1% or more and 20% or less. When adhesive parts 41 are provided on both sides of one electromagnetic steel sheet piece 40 in the stacking direction, the adhesion area ratio on both sides of the electromagnetic steel sheet pieces 40 is both 1% or more and 20% or less.

[0058] Furthermore, in this embodiment, it is preferable that the bonding area of ​​the core back portion 22 by the bonding portion 41 (hereinafter referred to as the "first bonding area S1") is equal to or larger than the bonding area of ​​the teeth portion 23 by the bonding portion 41 (hereinafter referred to as the "second bonding area S2"). In other words, it is preferable that S1≧S2. Here, the first adhesive area S1 is the area of ​​a region where the core back portion 45 of the adhesive portion 41 is provided on the first surface of the electromagnetic steel sheet piece 40. Similarly, the second adhesive area S2 is the area of ​​a region where the teeth portion 44 of the adhesive portion 41 is provided on the first surface of the electromagnetic steel sheet piece 40. Note that, like the area of ​​the region where the adhesive portion 41 is provided, the first adhesive area S1 and the second adhesive area S2 can be found, for example, by photographing the first surface of the electromagnetic steel sheet piece 40 after peeling and performing image analysis on the photographed result.

[0059] In the core block 24, if adjacent electromagnetic steel sheet pieces 40 in the stacking direction are not fixed to each other by some means, they will be displaced relative to each other. On the other hand, if adjacent electromagnetic steel sheet pieces 40 in the stacking direction are fixed to each other by, for example, crimping, plastic strain is applied to some of the electromagnetic steel sheet pieces 40, and the magnetic properties of the core block 24 will deteriorate. Crimping is a method of limiting the relative displacement between the stacked electromagnetic steel sheet pieces 40 by plastically deforming some of the electromagnetic steel sheet pieces 40 and causing them to bite into the stacking thickness direction. Since the magnetic properties of the electromagnetic steel sheet pieces 40 deteriorate when plastic strain is applied, using crimping as a method of fixing the electromagnetic steel sheet pieces 40 to each other will also deteriorate the magnetic properties of the entire core block 24. In contrast, in the core block 24 according to the present embodiment, the electromagnetic steel sheet pieces 40 adjacent to each other in the lamination direction are bonded to each other by the adhesive portion 41. Therefore, it is possible to suppress the relative displacement of the electromagnetic steel sheet pieces 40 adjacent to each other in the lamination direction in the entirety of the plurality of electromagnetic steel sheet pieces 40. Here, the adhesive area ratio of the electromagnetic steel sheet pieces 40 by the adhesive portion 41 is 1% or more. Therefore, the adhesiveness by the adhesive portion 41 is ensured, and the relative displacement of the electromagnetic steel sheet pieces 40 adjacent to each other in the lamination direction can be effectively restricted, for example, when winding the teeth portion 23 of the core block 24. Moreover, since the method of fixing the electromagnetic steel sheet pieces 40 is by adhesive rather than by crimping as described above, it is possible to suppress distortion occurring in the electromagnetic steel sheet pieces 40. From the above, it is possible to ensure the magnetic properties of the core block 24. Note that, if it is desired to further increase the adhesive strength and suppress separation of the electromagnetic steel sheet pieces 40 even when an impact is applied, it is more preferable to set the adhesive area ratio to 10% or more.

[0060] Incidentally, when an adhesive is applied to the electromagnetic steel sheet pieces 40, compressive stress occurs in the electromagnetic steel sheet pieces 40 as the adhesive hardens. Therefore, when adhesive is applied to the electromagnetic steel sheet pieces 40 to form the adhesive joints 41, distortion may occur in the electromagnetic steel sheet pieces 40. However, in the core block 24 according to the present embodiment, the adhesive area ratio of the electromagnetic steel sheet pieces 40 by the adhesive parts 41 is 60% or less. Therefore, it is possible to keep low the distortion caused by the adhesive in the electromagnetic steel sheet pieces 40. As a result, it is possible to further ensure the magnetic properties of the core block 24. Moreover, the adhesive area ratio of the electromagnetic steel sheet pieces 40 by the adhesive parts 41 is 20% or less. Therefore, the distortion caused in the electromagnetic steel sheet pieces 40 by the adhesive can be further reduced.

[0061] The adhesive portion 41 is provided on an adhesive region 42 formed on at least a part of the periphery of the electromagnetic steel sheet pieces 40. Therefore, for example, it is possible to suppress curling of the electromagnetic steel sheet pieces 40 adjacent to each other in the stacking direction. This makes it easier to wind the wire around the teeth portion 23 of the core block 24, and further ensures the magnetic properties of the core block 24. Therefore, it is possible to further ensure the magnetic properties of the core block 24.

[0062] When the width W1 (circumferential size) of the teeth portion 23 is narrower than the width W2 (radial size) of the core back portion 22, magnetic flux tends to concentrate in the teeth portion 23, increasing the magnetic flux density of the teeth portion 23. Therefore, when the adhesive applies distortion to the steel plate, the same amount of distortion has a greater effect on the magnetic properties of the teeth portion 23 than on the magnetic properties of the core back portion 22. In the present embodiment, it is preferable that the first adhesive area S1 is equal to or larger than the second adhesive area S2. In this case, the adhesive strength of the core block 24 as a whole in the core back portion 22 can be secured while suppressing the influence of deterioration of the magnetic properties due to distortion of the adhesive in the teeth portion 23.

[0063] The electromagnetic steel sheet pieces 40 forming the core block 24 are manufactured by punching an electromagnetic steel sheet as a base material. During the punching process, a strain caused by the punching process is applied from the periphery of the electromagnetic steel sheet pieces 40 toward the inside of the electromagnetic steel sheet pieces 40 to a width equivalent to the sheet thickness of the electromagnetic steel sheet pieces 40. The periphery of the electromagnetic steel sheet pieces 40 is work-hardened by the above-mentioned strain, so that deformation such as localized turning over of the periphery of the electromagnetic steel sheet pieces 40 is unlikely to occur. Therefore, even if the periphery of the electromagnetic steel sheet pieces 40 is not bonded, deformation of the electromagnetic steel sheet pieces 40 is unlikely to occur. Therefore, even if a non-bonded region 143 is formed on the periphery of the electromagnetic steel sheet pieces 40 as in the core block 124 according to the first modification shown in FIG. 4, deformation of the electromagnetic steel sheet pieces 40 can be suppressed. And by forming the non-bonded region 143 in this way, it is possible to suppress the application of unnecessary strain to the electromagnetic steel sheet pieces 40. Therefore, the magnetic properties of the core block 24 can be further ensured.

[0064] 4, by providing a non-contact region 143 between the periphery of the electromagnetic steel sheet pieces 40 and the adhesive portion 141, it is possible to prevent the uncured adhesive from spilling out from the periphery of the electromagnetic steel sheet pieces 40 when the electromagnetic steel sheet pieces 40 are stacked. If the adhesive hardens in a state where it spills out from the tip end of the teeth portion 23, it may interfere with the rotating rotor 30. If the adhesive hardens in a state where it spills out from the side portion of the teeth portion 23, it may cause the cross-sectional area of ​​the slot between the teeth portion 23 to be compressed, resulting in a decrease in the space factor of the coil.

[0065] The width of the non-bonded region 143 is preferably 1 to 10 times the sheet thickness of the electromagnetic steel sheet piece 40. By making the width of the non-bonded region 143 1 or more, it is possible to effectively prevent the adhesive from spilling out. Furthermore, by making the width of the non-bonded region 143 10 or less, it is expected that the effect of preventing curling of the electromagnetic steel sheet piece 40 due to work hardening from the periphery of the electromagnetic steel sheet piece 40 can be obtained. In this specification, the "width" of the non-adhesive region 143 means the dimension in a direction perpendicular to the direction in which each portion of the non-adhesive region 143 extends. It is preferable that the width of the non-adhesive region 143 is within the above-mentioned range over the entire length of the non-adhesive region 143.

[0066] In the core block 24, the magnetic flux extends from the tip of the tooth portion 23 in a diffused manner to both sides in the circumferential direction. Therefore, the magnetic flux is likely to concentrate at the tip of the tooth portion 23. Moreover, the magnetic flux enters the adjacent core block 24 from both ends in the circumferential direction of the core back portion 22. Therefore, the magnetic flux is likely to concentrate at both ends in the circumferential direction of the core back portion 22. If the adhesive region 42 is provided in the area where the magnetic flux is concentrated, the increase in iron loss is likely to become significant. Therefore, as shown in the second modification of FIG. 5, by providing the non-adhesive region 243 at the tip of the tooth portion 23 and both ends in the circumferential direction of the core back portion 22, the adhesive region 242 can be arranged away from the area with high magnetic flux density, and the increase in iron loss can be suppressed.

[0067] The magnetic flux B tends to flow through the shortest distance where the magnetic resistance is low. Therefore, in the core back portion 22, the magnetic flux density decreases from the radial inner side (one radial side) connected to the teeth portion 23 to the radial outer side (the other radial side) away from the teeth portion 23. On the other hand, as described above, the magnetic flux is likely to concentrate at the tip of the teeth portion 23 and both ends in the circumferential direction of the core back portion 22. In the modified example 3 of FIG. 6, the widths of the second portion 344b and the fifth portion 345c located at the tip of the teeth portion 23 and both ends in the circumferential direction of the core back portion 22 are narrower than the width of the fourth portion 345b extending along the radially outer periphery of the core back portion 22. That is, according to the modified example 3, the widths of the second portion 344b and the fifth portion 345c, where the magnetic flux density is likely to increase, are narrowed to suppress an increase in iron loss. Furthermore, according to the third modification, by increasing the width of the fourth portion 345b where the magnetic flux density is less likely to increase, the adhesive strength between the electromagnetic steel sheet pieces 40 can be increased and the effect of the adhesive portion 341 on iron loss can be reduced.

[0068] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0069] The shape of the core block 24 is not limited to the form shown in the above embodiment. The dimensions of each part of the core block 24 and the thickness of the electromagnetic steel sheet pieces 40 can be designed as desired according to the characteristics of the desired rotating electric machine.

[0070] In addition, in the core block, a convex shape may be provided on one circumferential end face of the core back portion, and a concave shape may be provided on the other circumferential end face of the core back portion. In this case, by inserting the convex shape into the concave shape, it is possible to suppress misalignment when multiple core blocks are connected in the circumferential direction.

[0071] The core block may have two or more teeth portions for one core back portion.Furthermore, the core block may have a core back portion and teeth portions which are separate from each other.

[0072] In the rotor in the above embodiment, a pair of permanent magnets 32 form one magnetic pole, but the present invention is not limited to this. For example, one permanent magnet 32 ​​may form one magnetic pole, or three or more permanent magnets 32 may form one magnetic pole.

[0073] In the above embodiment, a permanent magnet field type motor has been used as an example of a rotating electric motor, but the structure of the rotating electric motor is not limited to this, as exemplified below, and various known structures not exemplified below can also be adopted. In the above embodiment, a permanent magnet field motor is used as an example of a synchronous motor, but the present invention is not limited to this. For example, the rotating electric machine may be a reluctance motor or an electromagnetic field motor (wound field motor). In the above embodiment, a synchronous motor is used as an example of an AC motor, but the present invention is not limited to this. For example, the rotating electric machine may be an induction motor. In the above embodiment, an AC motor is used as an example of the electric motor, but the present invention is not limited to this. For example, the rotating electric machine may be a DC motor. In the above embodiment, an electric motor is used as an example of a rotating electric machine, but the present invention is not limited to this. For example, the rotating electric machine may be a generator.

[0074] In the above embodiment, the laminated core according to the present invention is applied to a stator core, but it may also be applied to a rotor core. Also, the laminated core according to the present invention may be applied to laminated cores other than those for rotating electrical machines, such as transformers.

[0075] In addition, within the scope of the invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate.

[0076] For example, the core block may be a combination of the configuration of Modification 1 and the configuration of Modification 2. That is, as in Modification 1 shown in Fig. 4, a non-contact region 143 may be provided between the periphery of the electromagnetic steel sheet piece 40 and the adhesive portion 141, and further, as in Modification 2 shown in Fig. 5, a non-adhesive region 243 may be provided at the tip of the tooth portion 23 and at both circumferential ends of the core back portion 22.

[0077] Similarly, the core block may be a combination of the configurations of Modification 1 and Modification 3. That is, as in Modification 1 shown in Fig. 4, a non-contact region 143 may be provided between the periphery of the electromagnetic steel sheet piece 40 and the adhesive portion 141, while the widths of the second portion 344b and the fifth portion 345c of the adhesive portion 341 may be configured to be narrower than the width of the fourth portion 345b, as in Modification 3 shown in Fig. 6. EXAMPLES

[0078] Next, verification tests (first to third verification tests) were carried out to verify the above-mentioned operational effects. The verification tests were carried out by simulation using software. The finite element method electromagnetic field analysis software JMAG manufactured by JSOL Corporation was used as the software.

[0079] (First verification test) 7 to 18 show 12 types of stator cores 21A to 21L for which simulations were performed in this verification test. All of these stator cores 21A to 21L have the basic structure of the stator core 21 according to the embodiment shown in FIG. 3, but the following points were changed from this stator core 21. The stator cores 21A to 21L each have a plurality of core blocks 24A to 24L. The sheet thickness of the electromagnetic steel sheet pieces 40 is 0.25 mm. The adhesive area ratios of the adhesive parts 41 of the electromagnetic steel sheet pieces 40 are different from one another, ranging from 0% to 100%. More specifically, the adhesive area ratio of the stator core 21A is 100%. The adhesive area ratio of the stator core 21B is 90%. The adhesive area ratio of the stator core 21C is 85%. The adhesive area ratio of the stator core 21D is 70%. The adhesive area ratio of the stator core 21E is 60%. The adhesive area ratio of stator core 21F is 50%. The adhesive area ratio of stator core 21G is 40%. The adhesive area ratio of stator core 21H is 30%. The adhesive area ratio of stator core 21I is 20%. The adhesive area ratio of stator core 21J is 15%. The adhesive area ratio of stator core 21K is 10%. The adhesive area ratio of stator core 21L is 0%.

[0080] The iron loss of the 12 types of stator cores 21A to 21L was obtained by the above simulation. As a comparison, the iron loss of a comparative stator core 21X in which a plurality of electromagnetic steel sheet pieces 40 are crimped in all layers, as shown in FIG. 19, was also obtained. The comparative stator core 21X has a plurality of core blocks 24X. The comparative stator core 21X also has an electromagnetic steel sheet piece 40 with a sheet thickness of 0.25 mm. The core block of the comparative stator core 21X is provided with a first crimp C1 provided in the core back portion 22 and two second crimps C2 provided in the teeth portion 23. The first crimp C1 is located at the circumferential center of the core back portion 22. The two second crimps C2 are aligned along the radial direction at the circumferential center of the teeth portion 23. The proportion of the area of ​​the first surface of the electromagnetic steel sheet piece 40 that is occupied by the crimps C1 and C2 is approximately 3.2%.

[0081] The results are shown in the graph of Fig. 20. In the graph of Fig. 20, the horizontal axis represents the adhesive area ratio of the electromagnetic steel sheet pieces 40 of the stator cores 21A-21L. The vertical axis represents the iron loss suppression rate Rt, which is obtained by dividing the difference between the iron loss of each of the stator cores 21A-21L and the iron loss of the comparative stator core 21X by the iron loss of the comparative stator core 21X, expressed as a percentage. That is, the iron loss suppression rate Rt on the vertical axis of the graph of Fig. 20 is expressed by the following formula (1) where the iron loss of each of the stator cores 21A-21L is W and the iron loss of the comparative stator core 21X is Worg.

[0082]

number

[0083] When the iron loss of electromagnetic steel sheet pieces 40 in each of stator cores 21A to 21L is equivalent to the iron loss in comparative stator core 21X, the value on the vertical axis is 0%. The smaller the iron loss suppression rate, the smaller the iron loss, indicating superior magnetic characteristics as a stator core.

[0084] 20, it was confirmed that by setting the bonding area ratio of the electromagnetic steel pieces 40 by the bonding parts 41 to 60% or less, the iron loss can be reduced compared to the comparative stator core 21X, which is the conventional technology. It was also confirmed that by setting the bonding area ratio of the electromagnetic steel pieces 40 by the bonding parts 41 to 40% or less, the iron loss can be improved by 3% or more compared to the comparative stator core 21X, which is the conventional technology. It was also confirmed that by setting the bonding area ratio of the electromagnetic steel pieces 40 by the bonding parts 41 to 20% or less, the iron loss can be improved by 5% or more compared to the comparative stator core 21X, which is the conventional technology.

[0085] (Second verification test) Next, the adhesive strength of the electromagnetic steel sheet pieces was examined when the adhesive area ratio was changed. First, we prepared a core block in which electromagnetic steel sheet pieces with a bonding area ratio of 0% (i.e., no bonding), a core block in which electromagnetic steel sheet pieces with a bonding area ratio of 0.5%, a core block in which electromagnetic steel sheet pieces with a bonding area ratio of 1%, and a core block in which electromagnetic steel sheet pieces with a bonding area ratio of 10%. Next, we wound wire around the teeth of these core blocks to check whether the winding could be performed smoothly. The verification results are shown in Table 1.

[0086] [Table 1]

[0087] In Table 1, "x" means that the core block collapsed due to the force applied to the core block during winding. "o" means that the winding was completed. This verification confirmed that the adhesive strength required for the winding can be ensured by setting the adhesive area ratio of the electromagnetic steel sheet pieces to 1% or more. When the adhesive strength of samples with adhesive area ratios of 1% and 10% was confirmed, it was confirmed that the sample with an adhesive area ratio of 10% had higher strength. From the viewpoint of obtaining sufficient adhesive strength to prevent peeling of the adhesive part when dropped, it is preferable to set the adhesive area ratio to 10% or more.

[0088] (Third Verification Test) This verification test is a verification test for the width of each part of the adhesive joint. The simulation conditions and dimensional conditions are the same as those of the first verification test.

[0089] 21 and 22 show two types of stator cores 21M and 21N for which simulations were carried out in this verification test. These stator cores 21M and 21N have the basic structure of the stator core 21 according to the embodiment shown in FIG.

[0090] In the adhesive portion 41M of the stator core 21M shown in Fig. 21, the width of the second portion 44b and the fifth portion 45c are wider than the width of the other portions. On the other hand, in the adhesive portion 41N of the stator core 21N shown in Fig. 22, the width of the fourth portion 45b is wider than the width of the other portions. In addition, the areas of the adhesive portions 41N of the stator cores 21M and 21N are equal to each other. Therefore, the adhesive strengths of the stator cores 21M and 21N are equal to each other.

[0091] When the iron loss of stator cores 21M and 21N was calculated by simulation, the iron loss of stator core 21N was 98% of that of stator core 21M. In other words, the iron loss of stator core 21N was improved by 2% compared to stator core 21M. This is believed to be because, in stator core 21N, the width of second portion 44b and fifth portion 45c is narrower than the width of fourth portion 45b, making it easier for magnetic flux to flow within stator core 21N. [Explanation of symbols]

[0092] 10...Rotary electric machine 21...Stator core (laminated core) 22…Core back section 23…Teeth 24,124,224,324…Core block 40...Electromagnetic steel sheet piece 41,141,241,341...Adhesive part 42,142,242…adhesion area 143,243…non-adhesive area 44a,244a,344a...first part 44b,344b…Second part 45a,245a,345a...3rd part 45b,245b,345b…4th part 45c,345c…5th part

Claims

1. A core block that constitutes a laminated core by connecting a plurality of core blocks in an annular shape, A plurality of magnetic steel sheet pieces stacked on top of each other; and an adhesive portion provided between the electromagnetic steel sheet pieces adjacent to each other in the stacking direction, and adhesively bonding the electromagnetic steel sheet pieces to each other, the electromagnetic steel sheet piece has an arc-shaped core back portion and a teeth portion protruding from the core back portion to one side in a radial direction of the core back portion, The adhesive portion is a pair of first portions extending along circumferential edges of the teeth on both circumferential sides; a pair of third portions each extending from a base end of the first portion to both sides in a circumferential direction along a peripheral edge on one side in a radial direction of the core back portion; a fourth portion extending in a circumferential direction along a peripheral edge of the core back portion on the other radial side, The adhesive area ratio of the electromagnetic steel sheet pieces by the adhesive portion is 1% or more and 60% or less, The adhesive portion is an acrylic adhesive of room temperature adhesive type containing SGA made of an elastomer-containing acrylic adhesive. Core block.

2. A core block that constitutes a laminated core by connecting a plurality of core blocks in an annular shape, A plurality of magnetic steel sheet pieces stacked on top of each other; and an adhesive portion provided between the electromagnetic steel sheet pieces adjacent to each other in the stacking direction, and adhesively bonding the electromagnetic steel sheet pieces to each other, the electromagnetic steel sheet piece has an arc-shaped core back portion and a teeth portion protruding from the core back portion to one side in a radial direction of the core back portion, The adhesive portion is a pair of first portions extending along circumferential edges of the teeth on both circumferential sides; a pair of third portions each extending from a base end of the first portion to both sides in a circumferential direction along a peripheral edge on one side in a radial direction of the core back portion; a fourth portion extending in a circumferential direction along a peripheral edge of the core back portion on the other radial side, The adhesive area ratio of the electromagnetic steel sheet pieces by the adhesive portion is 1% or more and 60% or less, The width of the fourth portion is larger than the widths of the first portion and the third portion, The bonding area of ​​the core back portion by the bonding portion is equal to or larger than the bonding area of ​​the teeth portion by the bonding portion. Core block.

3. The core block according to claim 1 , wherein the bonding area ratio is determined based on a relationship between the bonding area ratio and core loss.

4. 4. The core block according to claim 1, wherein the adhesion area ratio is 1% or more and 20% or less.

5. The adhesive portion further comprises: a second portion extending along a periphery of a tip of the tooth portion and connecting tips of the pair of first portions; The core block according to any one of claims 1 to 4, further comprising a pair of fifth portions extending along both circumferential edges of the core back portion and respectively connecting the third portion and the fourth portion.

6. The core block of claim 5 , wherein the second and fifth portions have a width less than a width of the fourth portion.

7. The core block according to any one of claims 1 to 6, wherein the adhesive portion is provided on at least a portion of a periphery of the electromagnetic steel sheet piece.

8. A core block according to any one of claims 1 to 7, wherein a non-adhesive region of the electromagnetic steel sheet piece where the adhesive portion is not provided is formed between the adhesive region of the electromagnetic steel sheet piece where the adhesive portion is provided and the periphery of the electromagnetic steel sheet piece.

9. The core block according to claim 8 , wherein a width of the non-bonded region is 1 to 10 times the sheet thickness of the electromagnetic steel sheet pieces.

10. A core block according to any one of claims 1 to 4, wherein in the electromagnetic steel sheet pieces, non-bonded areas of the electromagnetic steel sheet pieces where the adhesive portion is not provided are formed at the tips of the teeth portions and at both circumferential ends of the core back portion.

11. The core block according to claim 1 , wherein a bonding area of ​​the core back portion bonded by the bonding portion is equal to or larger than a bonding area of ​​the teeth portion bonded by the bonding portion.

12. The core block according to any one of claims 1 to 11, wherein the average thickness of the adhesive portion is 1.0 µm to 3.0 µm.

13. The core block according to any one of claims 1 to 12, wherein the average tensile modulus E of the adhesive joint is 1500 MPa to 4500 MPa.

14. 3. The core block according to claim 2, wherein the adhesive portion is an acrylic adhesive of room temperature adhesive type containing SGA made of an elastomer-containing acrylic adhesive.

15. The core block according to any one of claims 1 to 14 is configured by connecting a plurality of core blocks in an annular shape. Laminated core.

16. A rotating electric machine comprising the laminated core according to claim 15.

17. A method for producing a core block according to any one of claims 1 to 14, comprising the steps of: A method for manufacturing a core block, comprising: a first step of determining the bonding area ratio based on a relationship between the bonding area ratio and iron loss.

18. The method for manufacturing a core block according to claim 17 , further comprising a second step of bonding the electromagnetic steel sheet pieces adjacent in the stacking direction by the bonding portions in which the bonding area ratio is determined in the first step.

Images