Stator core, rotating electrical machine, and stator core design method

Abstract

The present invention is a stator core having a plurality of stacked electromagnetic steel sheets, wherein the width of teeth along a direction having excellent magnetic properties among a plurality of teeth (121a to 121p) of the stator core is smaller than the width of teeth along a direction having poor magnetic properties.

Description

Technical Field

[0001] The present invention relates to a stator core, a rotating electric machine and a design method of a stator core, and is particularly suitable for a stator core having a plurality of stacked electromagnetic steel sheets.

[0002] This application claims priority based on Japanese Patent Application No. 2019-206649 filed in Japan on November 15, 2019, and the contents of which are incorporated herein by reference. Background Art

[0003] Electromagnetic steel sheets are mainly used as stator cores of rotating electrical machines. Electromagnetic steel sheets are roughly divided into oriented electromagnetic steel sheets and non-oriented electromagnetic steel sheets. The magnetic properties of electromagnetic steel sheets generally have anisotropy within the plate surface. In particular, the anisotropy of the magnetic properties of oriented electromagnetic steel sheets is large, and the magnetic properties in the rolling direction are extremely good compared to other directions. On the other hand, even for non-oriented electromagnetic steel sheets, although the anisotropy of the magnetic properties is smaller than that of oriented electromagnetic steel sheets, anisotropy also exists in the magnetic properties. When such electromagnetic steel sheets with anisotropy in magnetic properties are stacked to form a stator core, parts with good magnetic properties and parts with bad magnetic properties are generated, and the distribution of the magnetic properties of the stator core will deviate. Specifically, a deviation in the magnetic flux density in the stator core will occur, and the iron loss will increase.

[0004] Patent Document 1 discloses a technology for a rotating electric machine, which makes the path size of the magnetic flux between the slot bottom and the outer periphery of the stator core (i.e., the radial length of the yoke of the stator core) smaller in a region with good magnetic characteristics and larger in a region with poor magnetic characteristics. In the technology for a rotating electric machine disclosed in Patent Document 1, by making the cross-sectional area of ​​the yoke of the stator core different according to the magnetic characteristics, the magnetic flux density is lower in a region with poor magnetic characteristics for the same magnetic flux.

[0005] Patent Document 2 discloses a technology for a three-pole core, which makes the surface area of ​​the magnetic pole teeth in the rolling direction or along the direction perpendicular to the rolling direction smaller than the surface area of ​​other magnetic pole teeth. In the three-pole core disclosed in Patent Document 2, by making the surface area of ​​the magnetic pole teeth in the rolling direction or along the direction perpendicular to the rolling direction smaller than the surface area of ​​other magnetic pole teeth, the core is made cheaper and the imbalance of magnetic flux can be eliminated.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 59-10142

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 8-214476 Summary of the invention

[0010] Technical problem to be solved by the invention

[0011] However, in the technology disclosed in Patent Document 1, since the magnetic flux flows from the teeth into the yoke in a curved manner, it is not easy to determine whether to increase or decrease the path size of a certain portion in the circumferential direction of the yoke. That is, in the technology of Patent Document 1, there is a risk that it is difficult to determine the shape of the stator core and that the deviation of the magnetic flux density cannot be reduced.

[0012] In addition, the technology disclosed in Patent Document 2 is based on the premise that the magnetic flux in the rolling direction or the direction perpendicular to the rolling direction is easier to pass than the magnetic flux in other directions, but the magnetic flux in the rolling direction or the direction perpendicular to the rolling direction may be difficult to pass. That is, there is a risk that even if the shape of the three-pole core is determined based on the rolling direction as in the technology of Patent Document 2, the deviation of the magnetic flux density cannot be reduced.

[0013] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to reduce the variation in magnetic flux density and thereby suppress the iron loss.

[0014] Technical means for solving technical problems

[0015] In order to solve the above-mentioned problems, the present invention adopts the following configuration.

[0016] (1) A stator core according to one embodiment of the present invention is a stator core having a plurality of stacked electromagnetic steel sheets, wherein among a plurality of teeth of the stator core, a width of a tooth along a direction having excellent magnetic properties is smaller than a width of a tooth along a direction having poor magnetic properties.

[0017] (2) In the stator core described in (1) above, the product of the width of the stator core teeth and the magnetic flux density of the teeth when excited with a predetermined magnetic field intensity may be substantially constant in each tooth.

[0018] (3) In the stator core described in (1) or (2) above, the stator core is formed by laminating rolled electromagnetic steel plates, and the electromagnetic steel plates have the following chemical composition: in terms of mass %, C: 0.0100% or less, Si: 1.50% to 4.00%, sol.Al: 0.0001% to 1.0%, S: 0.0100% or less, N: 0.0100% or less, at least one selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au: 2.50% to 5.00% in total, Sn: 0.000% to 1.0% 0.400%, Sb: 0.000% to 0.400%, P: 0.000% to 0.400%, and one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: 0.0000% to 0.0100% in total, wherein the Mn content (mass %) is denoted as [Mn], the Ni content (mass %) is denoted as [Ni], the Co content (mass %) is denoted as [Co], the Pt content (mass %) is denoted as [Pt], the Pb content (mass %) is denoted as [Pb], and the Cu content (mass %) is denoted as [Cu], when the Au content (mass %) is recorded as [Au], the Si content (mass %) is recorded as [Si], and the sol.Al content (mass %) is recorded as [sol.Al], the following formula (1) is satisfied, and the remainder is composed of Fe and impurities, and when the value of B50 in the rolling direction is recorded as B50L, the value of B50 in the direction inclined by 45° from the rolling direction is recorded as B50D1, the value of B50 in the direction inclined by 90° from the rolling direction is recorded as B50C, and the value of B50 in the direction inclined by 135° from the rolling direction is recorded as B50D2, the following formula is satisfied According to formula (2) and formula (3), the X-ray random intensity ratio of {100}<011> is greater than 5 and less than 30, the plate thickness is less than 0.50 mm, the direction in which the magnetic properties are excellent is the direction at an angle of 45° to the rolling direction, the direction in which the magnetic properties are poor is the directions at angles of 0° and 90° to the rolling direction, and the width of the tooth along the direction at an angle of 45° to the rolling direction is smaller than any of the width of the tooth along the direction at an angle of 0° to the rolling direction and the width of the tooth along the direction at an angle of 90° to the rolling direction.

[0019] ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])>0%···(1)

[0020] (B50D1+B50D2) / 2>1.7T···(2)

[0021] (B50D1+B50D2) / 2>(B50L+B50C) / 2···(3)

[0022] Here, the magnetic flux density B50 refers to the magnetic flux density when the magnet is excited with a magnetic field intensity of 5000 A / m.

[0023] (4) The stator core described in (3) above may satisfy the following formula (4).

[0024] (B50D1+B50D2) / 2>1.1×(B50L+B50C) / 2···(4)

[0025] (5) The stator core described in (3) above may satisfy the following formula (5).

[0026] (B50D1+B50D2) / 2>1.2×(B50L+B50C) / 2···(5)

[0027] (6) The stator core described in (3) above may satisfy the following formula (6).

[0028] (B50D1+B50D2) / 2>1.8T···(6)

[0029] (7) A rotating electrical machine according to one aspect of the present invention includes the stator core described in any one of (1) to (6) above.

[0030] (8) A stator core design method according to one embodiment of the present invention is a stator core design method having stacked electromagnetic steel plates, comprising: a tooth magnetic flux density acquisition step for acquiring information on the magnetic flux density of teeth when the magnetic field is excited with a predetermined magnetic field strength; and a determination step for determining the width of the teeth of the stator core so that the product of the width of the teeth of the stator core and the magnetic flux density of the teeth obtained by the tooth magnetic flux density acquisition step is approximately constant in each tooth.

[0031] (9) It may be that the design method of the stator core as described in (8) above has an operation data acquisition process, a determination process, an average magnetic flux density acquisition process, and an average magnetic field strength calculation process, the operation data acquisition process acquires the operation data of the rotating electric machine when the rotating electric machine equipped with the stator core is operated, the determination process determines the operating condition with the highest proportion of operation time among multiple operating conditions based on the operation data acquired by the operation data acquisition process, the average magnetic flux density acquisition process acquires information on the average magnetic flux density of the teeth corresponding to the operating condition with the highest proportion determined by the determination process, and the average magnetic field strength calculation process calculates the intensity of the average magnetic field of the teeth based on the information on the average magnetic flux density of the teeth acquired by the average magnetic flux density acquisition process; in the tooth magnetic flux density acquisition process, information on the magnetic flux density of the teeth when excited with the intensity of the average magnetic field calculated by the average magnetic field strength calculation process is acquired.

[0032] (10) It may be that the design method of the stator core described in (8) above has an operation data acquisition step, a determination step, an average magnetic flux density acquisition step, and an average magnetic field strength calculation step, the operation data acquisition step acquires the operation data of the rotating electric machine when the rotating electric machine equipped with the stator core is operated, the determination step determines the proportion of the operation time of each of a plurality of operation conditions based on the operation data acquired by the operation data acquisition step, the average magnetic flux density acquisition step acquires information on the average magnetic flux density of the teeth corresponding to each of the plurality of operation conditions, and the average magnetic field strength calculation step calculates the average magnetic field strength based on the average magnetic flux density of the teeth corresponding to each of the plurality of operation conditions acquired by the average magnetic flux density acquisition step. The tooth width is calculated for each of the plurality of operating conditions based on the information of the degree of the tooth intensity. In the tooth flux density acquisition process, the tooth flux density information of each of the plurality of operating conditions when the tooth is excited by the tooth intensity of the average magnetic field of each of the plurality of operating conditions calculated by the average magnetic field intensity calculation process is obtained. In the determination process, the tooth width is calculated for each of the plurality of operating conditions, and the calculated tooth width of each of the plurality of operating conditions is weighted based on the ratio of the operating time determined by the determination process, thereby determining the weighted tooth width so that the product of the width of the tooth of the stator core and the tooth flux density obtained by the tooth flux density acquisition process is approximately constant in each tooth.

[0033] (11) It may be that the design method of the stator core as described in (8) above has an operation data acquisition step, a determination step, an average magnetic flux density acquisition step, an evaluation magnetic flux density calculation step, and an average magnetic field strength calculation step, wherein the operation data acquisition step acquires the operation data of the rotating electric machine when the rotating electric machine having the stator core is operated, the determination step determines the proportion of the operation time of each of a plurality of operation conditions based on the operation data acquired by the operation data acquisition step, and the average magnetic flux density acquisition step acquires the average magnetic flux density of the teeth corresponding to each of the plurality of operation conditions. The evaluation magnetic flux density calculation process calculates the evaluation magnetic flux density of the tooth weighted based on the proportion of the operating time determined by the determination process based on the information of the average magnetic flux density of the tooth corresponding to each of the multiple operating conditions obtained by the average magnetic flux density acquisition process; the average magnetic field strength calculation process calculates the strength of the average magnetic field of the tooth based on the evaluation magnetic flux density of the tooth calculated by the evaluation magnetic flux density calculation process; in the tooth magnetic flux density acquisition process, the information of the magnetic flux density of the tooth when excited by the strength of the average magnetic field of the tooth calculated in the average magnetic field strength calculation process is obtained.

[0034] (12) In the stator core design method described in any one of (9) to (11) above, at least one of planned data and actual performance data of a rotating electrical machine having the stator core may be acquired in the operation data acquisition step.

[0035] Effects of the Invention

[0036] According to the above aspect of the present invention, it is possible to reduce the variation in magnetic flux density and suppress the iron loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a diagram showing an example of the structure of a rotating electrical machine.

[0038] Figure 2 This is a graph showing the relationship between the angle with the rolling direction and the magnetic properties.

[0039] Figure 3 It is a diagram for explaining the width of teeth.

[0040] Figure 4 This is a diagram showing an example of the structure of a motor.

[0041] Figure 5 The diagram shows angles of 0° to 90° with the rolling direction in the stator core.

[0042] Figure 6 This is a table showing the relationship between the torque ratio and the average magnetic flux density of the teeth.

[0043] Figure 7 This is a table showing the relationship between the torque ratio and the magnetic flux density of each tooth at each angle with the rolling direction (material A).

[0044] Figure 8 This is a table showing the relationship between the torque ratio and the optimum width of the tooth for each angle with the rolling direction (material A).

[0045] Fig. 9 This is a table showing the iron loss ratio between the comparative example and the invention example (material A).

[0046] Fig.10 This is a table showing an example of operating data.

[0047] Fig.11 This is a table showing the tooth width weighted based on the ratio of the operation time for each angle with the rolling direction (material A).

[0048] Fig.12 This is a table showing the relationship between the torque ratio and the magnetic flux density of each tooth at each angle with the rolling direction (material B).

[0049] Fig.13 This is a table showing the relationship between the torque ratio and the optimum width of the tooth for each angle with the rolling direction (material B).

[0050] Fig.14 This is a table showing the iron loss ratio between the comparative example and the invention example (material B).

[0051] Fig.15 This is a table showing the tooth width weighted based on the ratio of the operation time for each angle with the rolling direction (material B).

[0052] Fig.16 This is a diagram showing an example of the structure of a motor.

[0053] Fig.17 The diagram shows angles of 0° to 90° with the rolling direction in the stator core.

[0054] Fig.18 This is a table showing the relationship between the torque ratio and the average magnetic flux density of the teeth.

[0055] Fig.19 This is a table showing the relationship between the torque ratio and the magnetic flux density of each tooth at each angle with the rolling direction (material A).

[0056] Fig. 20 This is a table showing the relationship between the torque ratio and the optimum width of the tooth for each angle with the rolling direction (material A).

[0057] Fig.21 This is a table showing the iron loss ratio between the comparative example and the invention example (material A).

[0058] Fig. 22 This is a table showing the tooth width weighted based on the ratio of the operation time for each angle with the rolling direction (material A).

[0059] Fig.23 This is a table showing the relationship between the torque ratio and the magnetic flux density of each tooth at each angle with the rolling direction (material B).

[0060] Fig.24 This is a table showing the relationship between the torque ratio and the optimum width of the tooth for each angle with the rolling direction (material B).

[0061] Fig.25 This is a table showing the iron loss ratio between the comparative example and the invention example (material B).

[0062] Fig.26 This is a table showing the tooth width weighted based on the ratio of the operation time for each angle with the rolling direction (material B).

[0063] Fig. 27 This is a diagram showing an example of the functional configuration of a stator core design device.

[0064] Fig.28 This is a flowchart showing an example of processing of the stator core design device.

[0065] Fig.29 This is a flowchart showing an example of processing of the stator core design device.

[0066] Fig.30 This is a flowchart showing an example of processing of the stator core design device. DETAILED DESCRIPTION

[0067] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the X-Y-Z coordinates shown in each figure represent the relationship between the directions in each figure, and the origin of the X-Y-Z coordinates is not limited to the position shown in each figure. In addition, in the following description, the same length, shape, direction, size, interval and other physical quantities are not limited to being completely the same, and also include the case where they are different within the range that does not damage the function of the part as the object.

[0068] <Structure of rotating electrical machines>

[0069] Figure 1 1 is a diagram showing an example of the structure of the rotating electrical machine 100. Specifically, Figure 11 is a diagram showing a cross section of the rotating electrical machine 100 cut perpendicularly to its axis O. In the following description, the circumferential direction (direction around the axis O of the rotating electrical machine 100), the radial direction (direction radially extending from the axis O of the rotating electrical machine 100), and the height direction (direction parallel to the axis O (Z-axis direction)) of the rotating electrical machine 100 are referred to as the circumferential direction, the radial direction, and the height direction, respectively, as needed. In addition, the axis O of the rotating electrical machine 100 is referred to as the axis O as needed.

[0070] exist Figure 1 In the embodiment, the rotary electric machine 100 includes a rotor 110 and a stator 120 .

[0071] The rotor 110 is coaxially mounted on the rotating shaft 130 (axis O) directly or via a member. The rotor 110 includes, for example, a rotor core, a permanent magnet, and a rotating shaft. The rotor 110 can be realized by a known technique, and thus a detailed description thereof is omitted here.

[0072] The stator 120 is coaxially arranged outside the rotor 110 with respect to the rotating shaft 130 (axis O). The stator 120 has a stator core and a winding. Figure 1 , the illustration of the winding is omitted. The stator core has a plurality of teeth 121a to 121p and a yoke 122. The yoke 122 has a substantially hollow cylindrical shape. The teeth 121a to 121p extend radially from the inner circumferential surface of the yoke 122 toward the axis O. The teeth 121a to 121p are arranged at equal intervals in the circumferential direction. The teeth 121a to 121p and the yoke 122 are integrated. That is, there is no boundary line between the teeth and the yoke. In addition, in the case of a so-called split core, there is no boundary line in the yoke.

[0073] The positions of the rotor 110 and the stator 120 are determined as follows: the front end faces of the plurality of teeth 121a to 121p are opposite to the outer peripheral surface of the rotor core of the rotor 110 with a gap (air gap). In addition, the winding (coil) is arranged on each of the plurality of teeth 121a to 121p in a state of being electrically insulated from the teeth 121a to 121p. The winding method of the winding can be either distributed winding or concentrated winding. A rotating magnetic field is generated by passing an excitation current through the winding of the stator 120, and the rotor 110 rotates due to the rotating magnetic field.

[0074] Here, the case where the rotating electrical machine 100 is an inner rotor type electric motor is described as an example. Examples of applicable objects of the electric motor include electric vehicles, hybrid electric vehicles, and compressors, but the applicable objects of the electric motor are not particularly limited.

[0075] In the present embodiment, the stator core is formed using a non-oriented electromagnetic steel sheet as an example of an electromagnetic steel sheet. As the non-oriented electromagnetic steel sheet, for example, a non-oriented electromagnetic steel sheet in accordance with “non-oriented electromagnetic steel strip” specified in JIS C2552 (2014) is used.

[0076] As the overall shape of the plane that conforms to the stator core ( Figure 1 The stator core is formed by stacking and fixing a plurality of non-oriented electromagnetic steel sheets having the same shape and size. The stator core is fixed by, for example, riveting. The method for punching the non-oriented electromagnetic steel sheets is not particularly limited. For example, the non-oriented electromagnetic steel sheets can be punched by a punching process using a die or a wire discharge process.

[0077] exist Figure 1 In order to facilitate the following description, the angles are marked into two types. Figure 1 The angles (0°, 22.5°, 45°, 67.5°, 90°) shown without brackets are angles less than 90° among the angles formed by the rolling direction of the non-oriented electromagnetic steel sheet and the radial direction of the teeth 121a~121p when the rolling direction of the non-oriented electromagnetic steel sheet is used as a reference. Figure 1 The angles shown in brackets (0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135°, 157.5°, 180°, 202.5°, 225°, 247.5°, 270°, 292.5°, 315°, 337.5°, 360°) are expressed with the direction toward the positive direction of the X axis in the rolling direction of the non-oriented electromagnetic steel sheet as the reference (0[°]), and the direction toward the positive direction of the X axis is taken as the reference. Figure 1 The angle is expressed in the case where the positive direction is the counterclockwise direction. Figure 1 In the figure, the angle shown without brackets is notated differently from the angle shown after it with brackets, but their meanings are the same.

[0078] Here, the radial direction of the teeth 121a to 121p is the same as the virtual line (at Figure 1 The virtual line passes through the circumferential center of the teeth 121a to 121p and the axis O, and is parallel to the plane (X-Y plane) perpendicular to the axis O (the axis of the stator core). Figure 1 In FIG. 1 , a case where the rolling direction of the non-oriented electromagnetic steel sheet is the X-axis direction is described as an example.

[0079] In the following description, when the rolling direction of the non-oriented electromagnetic steel sheet is used as a reference, the angle formed by the rolling direction of the non-oriented electromagnetic steel sheet and the radial direction of the teeth 121a to 121p is referred to as the angle formed with the rolling direction. In addition, in the following description, for the sake of convenience, the angle formed with the rolling direction may be referred to as Figure 1 The angles defined as the angles shown without brackets in the figure are sometimes referred to as Figure 1 The angles defined as the angles shown in brackets are described herein, but as described above, the angles shown without brackets and the angles shown after them with brackets are different in notation method, but have the same meaning.

[0080] In this embodiment, the plurality of non-oriented electromagnetic steel sheets punched out as described above are stacked in a state where the angles formed with respect to the rolling direction are aligned. That is, among the regions of the plurality of non-oriented electromagnetic steel sheets punched out as described above, the regions belonging to the same tooth (as in the example Figure 1 The angle formed by the rolling direction (in the case where the angle is defined as the angle shown without brackets in ) will be the same.

[0081] In this embodiment, a case is described in which a stator core is constructed using two types of non-oriented electromagnetic steel sheets, a first non-oriented electromagnetic steel sheet (referred to as material A) and a second non-oriented electromagnetic steel sheet (referred to as material B) having magnetic properties different with respect to the angle with the rolling direction.

[0082] Material A is a steel plate with the best magnetic properties at an angle of 0° with the rolling direction and relatively small anisotropy. Material B is a steel plate with the best magnetic properties at an angle of 45° with the rolling direction and relatively large anisotropy.

[0083] Figure 2 It is a graph showing the relationship between the angle with the rolling direction and the magnetic properties of each material A and material B. As an example, the magnetic property is the magnitude of the magnetic flux density, and here, it is the magnitude of the magnetic flux density when excited with a magnetic field strength of 5000 [A / m] (B50).

[0084] Curve 201 represents the normalized magnetic flux density B50 of material A, and curve 202 represents the normalized magnetic flux density B50 of material B. The normalized magnetic flux density B50 in curves 201 and 202 is expressed as a ratio when the average value of B50 of each angle formed with the rolling direction in each material A is normalized to 1.000. Figure 2 In order to facilitate marking, the angle with the rolling direction is marked as Figure 1 The angles shown in brackets are marked the same.

[0085] In material A, the magnetic flux density becomes the largest at an angle of 0° with the rolling direction, and the magnetic flux density increases at intervals of 90° from the angle of 0°. In addition, the magnetic flux density decreases near the angle of 45° with the rolling direction, and the magnetic flux density decreases at intervals of 90° from the angle of 45°. That is, in material A, the directions with excellent magnetic properties are the angles of 0°, 90°, 180°, and 270° with the rolling direction, and the directions with poor magnetic properties are the angles of 45°, 135°, 225°, and 315° with the rolling direction. Below, as representative values ​​of the directions with poor magnetic properties of material A, they are recorded as angles of 45°, 135°, 225°, and 315° with the rolling direction. In addition, in material A, the magnetic flux density in the range of angles 0° to 90° and the magnetic flux density in the range of angles 90° to 180° are roughly symmetrical with an angle of 90° as the boundary. Furthermore, in the material A, the magnetic flux density in the range of angles 0° to 180° and the magnetic flux density in the range of angles 180° to 360° are substantially symmetrical with the angle 180° as a boundary.

[0086] On the other hand, in material B, the magnetic flux density becomes the largest at an angle of 45° with the rolling direction, and the magnetic flux density increases at intervals of 90° from an angle of 45°. In addition, near the angle of 0° with the rolling direction, the magnetic flux density decreases, and the magnetic flux density decreases at intervals of 90° from an angle of 0°. That is, in material B, the directions with excellent magnetic properties are 45°, 135°, 225°, and 315° with the rolling direction, and the directions with poor magnetic properties are near the angles of 0°, 90°, 180°, and 270° with the rolling direction. Below, as representative values ​​of the directions with poor magnetic properties of material B, they are recorded as angles of 0°, 90°, 180°, and 270° with the rolling direction. In addition, in material B, the magnetic flux density in the range of angles 0° to 90° and the magnetic flux density in the range of angles 90° to 180° are roughly symmetrical with an angle of 90° as the boundary. Furthermore, in the material B, the magnetic flux density in the range of angles 0° to 180° and the magnetic flux density in the range of angles 180° to 360° are substantially symmetrical with the angle 180° as a boundary.

[0087] like Figure 2 As shown in FIG. 1 , when the stator core is constructed using material A or material B whose magnetic flux density varies depending on the angle with the rolling direction, the angles formed between the radial direction of each tooth of the stator core and the rolling direction are different, so the magnetic flux density of each tooth when a predetermined magnetic field strength is excited will be different. Therefore, since the magnetic flux density in the stator core varies, the iron loss will increase. When a rotating electric machine is constructed using such a stator core, the efficiency of the rotating electric machine will decrease.

[0088] The inventors of the present invention intend to adjust the width of each tooth in order to reduce the deviation of the magnetic flux density in the stator core. Specifically, the inventors considered that the width of the teeth along the direction of excellent magnetic characteristics can be made smaller than the width of the teeth along the direction of poor magnetic characteristics, or the width of the teeth along the direction of poor magnetic characteristics can be made larger than the width of the teeth along the direction of excellent magnetic characteristics. Furthermore, the inventors considered that in order to further reduce the deviation of the magnetic flux density, the width of the tooth can be determined in a manner that the "tooth width" × "tooth magnetic flux density" is approximately constant in each tooth.

[0089] When the stator core is constructed based on the above concept, the stator core is constructed as follows: Figure 1 Among the teeth 121 a to 121 p shown, the width of the teeth along the direction of excellent magnetic characteristics is smaller than the width of the teeth along the direction of poor magnetic characteristics.

[0090] Specifically, first, material A is used to form Figure 1 In the case of the stator core shown, in material A, the direction with excellent magnetic properties is the direction with an angle of 0° with the rolling direction. Here, in material A, the direction with excellent magnetic properties is the direction with an angle of 0° with the rolling direction, which refers to the directions with angles of 90°, 180°, and 270° with the rolling direction in addition to the angle of 0°. In addition, in material A, the direction with poor magnetic properties is the direction with an angle of 45° with the rolling direction. Here, in material A, the direction with poor magnetic properties is the direction with an angle of 45° with the rolling direction, which refers to the directions with angles of 135°, 225°, and 315° with the rolling direction in addition to the angle of 45°. That is, in material A, the angles of 0°, 90°, 180°, and 270° with the rolling direction are directions with excellent magnetic properties, and the angles of 45°, 135°, 225°, and 315° are directions with poor magnetic properties. Therefore, by making the width of each tooth of the teeth 121a, 121e, 121i, and 121m smaller than the width of each tooth of the teeth 121c, 121g, 121k, and 121o, it is possible to reduce the variation in the magnetic flux density in the stator core.

[0091] On the other hand, when material B is used to form Figure 1In the case of the stator core shown in FIG. 1 , in material B, the direction with excellent magnetic properties is the direction with an angle of 45° with the rolling direction. Here, in material B, the direction with excellent magnetic properties is the direction with an angle of 45° with the rolling direction, which means that in addition to the angle of 45°, there are also directions with angles of 135°, 225°, and 315° with the rolling direction. In addition, in material B, the direction with poor magnetic properties is the direction with an angle of 0° and 90° with the rolling direction. Here, in material B, the direction with poor magnetic properties is the direction with an angle of 0° and 90° with the rolling direction, which means that in addition to the angle of 0° and 90°, there are also directions with angles of 180° and 270° with the rolling direction. That is, in material B, the angles of 45°, 135°, 225°, and 315° with the rolling direction are directions with excellent magnetic properties, and the angles of 0°, 90°, 180°, and 270° are directions with poor magnetic properties. Therefore, by making the width of each tooth of the teeth 121c, 121g, 121k, and 121o smaller than the width of each tooth of the teeth 121a, 121e, 121i, and 121m, it is possible to reduce the variation in the magnetic flux density in the stator core.

[0092] Here, for the width of the teeth, refer to Figure 3 Provide explanation. Figure 3 It is a diagram for explaining the width of teeth. Figure 3 (a) is an example of teeth parallel to the radial direction. In this example, the teeth themselves are parallel to the radial direction. Figure 3 (b) is an example of teeth in which slots are parallel in the radial direction. In this example, the slots between teeth adjacent to each other in the circumferential direction are parallel in the radial direction.

[0093] The so-called tooth width in this embodiment is set as the circumferential length of the stator core at the central position of the tooth straight line area. Regarding the tooth straight line area, in the cross section of the stator core when cut in a direction perpendicular to the axis of the stator core, for each of the two ends of the teeth in the circumferential direction of the stator core, the area of ​​the longest straight line among the straight lines constituting the ends of the teeth in the circumferential direction of the stator core is obtained.

[0094] exist Figure 3 In the example shown in (a), the straight line connecting the positions 311 and 312 and the straight line connecting the positions 313 and 314 are the tooth straight line areas. Figure 3 In the example shown in (a), the center positions of the tooth straight line area are positions 321 and 322. Therefore, Figure 3 The width of the tooth shown in (a) is the distance TW between the position 321 and the position 322.

[0095] exist Figure 3In the example shown in (b), the straight line connecting the positions 315 and 316 and the straight line connecting the positions 317 and 318 are the tooth straight line areas. Figure 3 In the example shown in (b), the center position of the tooth straight line area is position 323, 324. Therefore, Figure 3 The width of the tooth shown in (b) is the distance TW between the position 323 and the position 324.

[0096] exist Figure 3 In (a), since this is an example of teeth parallel to the radial direction, the width of the tooth is constant regardless of the radial position in the tooth straight line area.

[0097] On the other hand, Figure 3 In (b), since it is an example of a tooth in which the groove is parallel to the radial direction, the actual tooth width varies depending on the radial position in the tooth straight line area. Therefore, as a representative value, the tooth width is set to the distance TW between the above-mentioned position 323 and position 324.

[0098] <Example of determining the width of a tooth (teeth with grooves parallel to the radial direction (material A))>

[0099] Next, when the electromagnetic steel sheet is material A and the stator core of the embedded permanent magnet synchronous motor is designed, an example of determining the width of the tooth in such a way that the above-mentioned "tooth width" × "tooth magnetic flux density" is approximately constant in each tooth will be described. In addition, in the example of the embedded permanent magnet synchronous motor shown here, regarding the teeth of the stator core, as shown in FIG. Figure 3 As shown in (b), the grooves are parallel along the radial direction.

[0100] Figure 4 1 is a diagram showing an example of the configuration of the motor 400 before the width of the teeth is determined, that is, the width of each tooth is constant over the entire circumference. Figure 4 , a cross section of the motor 400 cut perpendicularly to the axis O thereof is shown.

[0101] exist Figure 4 In the figure, the motor 400 is an interior permanent magnet synchronous motor (IPMSM: Interior Permanent Magnet Synchronous Motor) and includes a rotor 410 and a stator 420 .

[0102] The rotor 410 is coaxially mounted on the rotating shaft 430 (axis O). The rotor 410 has a plurality of permanent magnets 411. The permanent magnets 411 are embedded in the rotor core 415. Figure 4 As shown, the number of poles of the motor 400 is 8. The outer diameter of the rotor 410 is 133 [mm].

[0103] The stator 420 has a stator core 421 and a winding 422. The outer diameter of the stator 420 is 207 [mm], and the inner diameter of the stator 420 is 135 [mm]. The number of slots of the stator core 421 is 48. The winding 422 is distributed winding.

[0104] Figure 5 Yes Figure 4 The enlarged view is an extracted and enlarged view of a portion of the stator core 421 at an angle of 0° to 90° with the rolling direction. Here, the tooth 501a among the teeth 501a to 501m of the stator core 421 is located at an angle of 0° with the rolling direction, and 1 / 2 of the width of the tooth is omitted in the illustration. In addition, the tooth 501m among the teeth 501a to 501m is located at an angle of 90° with the rolling direction, and 1 / 2 of the width of the tooth is omitted in the illustration.

[0105] In addition, each tooth Figure 3 As shown in (b), the grooves are parallel in the radial direction. Figure 5 As shown in the figure, the width TW1 of the root of the tooth is 6.56 mm, and the width TW2 of the front end is 5.16 mm. Therefore, by calculating (6.56 mm + 5.16 mm) ÷ 2, the width of the tooth ( Figure 3 The TW) shown in (b) is 5.86 mm.

[0106] Here, in Figure 6 2 shows the results of analyzing the relationship between the operating conditions (torque ratio) and the average magnetic flux density of the teeth when the rotation speed of the motor 400 is 3,000 [rpm] and the width of the teeth is constant over the entire circumference of the stator core 421.

[0107] Figure 6 represents the torque ratio [%] and the average magnetic flux density B [T peak ] is a table showing the relationship between the torque ratio and the torque ratio of each operating condition. Here, the so-called torque ratio means the ratio of the torque under each operating condition when the maximum torque is 100[%]. For example, the so-called torque ratio of 20[%] means that the operation is carried out at the torque value [Nm] of the maximum torque [Nm] × 0.2. In addition, the so-called average magnetic flux density of the tooth refers to the value obtained by averaging the maximum value of the magnetic flux density at each position among the 48 teeth. That is, the so-called [T peak The "peak" in ] refers to the peak value of the magnetic flux density when the magnetic flux density changes over time. Figure 6 As the torque ratio increases, the average magnetic flux density of the teeth increases. Figure 6The relationship between the torque ratio and the average magnetic flux density of the teeth shown can be derived by performing electromagnetic field analysis (numerical analysis) based on Maxwell's equations or by measuring the induced voltage using a search coil in the iron core of the manufactured motor and integrating the induced voltage. In the case of obtaining it by electromagnetic field analysis (numerical analysis), the average magnetic flux density is obtained by the following method: In the finite element method, the maximum magnetic flux density is calculated for each element (all meshes) included in the tooth portion (in this example, all 48 teeth), and the average is calculated in consideration of the area of ​​each element. In the case of actual measurement using a search coil, the average magnetic flux density is obtained by integrating the measured induced voltage for each search coil, obtaining the time waveform of the magnetic flux density, and on this basis, calculating the maximum magnetic flux density and averaging it in consideration of the cross-sectional area of ​​the iron core surrounded by each search coil.

[0108] according to Figure 6 The average magnetic flux density of the teeth shown is used to calculate the average magnetic field strength H [A / m] of the teeth. The average magnetic field strength of the teeth can be calculated based on the relative magnetic permeability of material A. Here, for each torque ratio (i.e., Figure 6 The average magnetic flux density of each tooth shown in FIG. 1 is used to calculate the intensity of the average magnetic field of each tooth. Next, the magnetic flux density B[T] of each tooth at an angle to the rolling direction when excited with the intensity of the average magnetic field of the tooth is calculated based on the material properties of material A. Therefore, for each torque ratio (i.e., Figure 6 For each of the average magnetic flux densities of the teeth shown, the magnetic flux density of each tooth at each angle to the rolling direction is calculated.

[0109] Figure 7 This is a table showing the relationship between the torque ratio [%] and the magnetic flux density B [T] of each tooth at the angle to the rolling direction. Here, the angles of 0°, 22.5°, 45°, 67.5°, and 90° to the rolling direction are taken as representative values, and the three teeth centered around the representative angles are set to have the same magnetic flux density.

[0110] The tooth with an angle of 0° to the rolling direction is Figure 5 The teeth 501a and 501b are included in the 0° range (A1) shown in FIG. 1. In addition, the teeth forming an angle of 22.5° with the rolling direction are Figure 5 The teeth 501c to 501e are included in the 22.5° range shown. In addition, the teeth that form an angle of 45° with the rolling direction are Figure 5 The teeth 501f to 501h are included in the 45° range (A3) shown in FIG. 1. In addition, the teeth forming an angle of 67.5° with the rolling direction are Figure 5The teeth 501i to 501k are included in the 67.5° range (A4) shown in FIG. 1. In addition, the teeth forming an angle of 90° with the rolling direction are Figure 5 The 90° range (A5) shown includes teeth 5011 and 501m.

[0111] like Figure 7 As shown in the figure, when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the magnetic flux density of each tooth at an angle to the rolling direction will deviate. In addition, when the torque ratio is 40[%], 60[%], and 80[%], the magnetic flux density of the teeth at an angle of 0° and 90° to the rolling direction is larger, and the magnetic flux density of the teeth at an angle of 45° to the rolling direction is smaller. This tendency is consistent with the following tendency: Figure 2 The curve 201 of material A shown in FIG. 1 shows that the B50 ratio at the angles 0° and 90° with the rolling direction is large, and the B50 ratio at the angle 45° with the rolling direction is small. Figure 7 As shown, when the torque ratio is 100[%], the magnetic flux density of the tooth is constant regardless of the angle with the rolling direction because of magnetic saturation.

[0112] Figure 7 The relationship between the torque ratio and the magnetic flux density of each tooth at the angle formed with the rolling direction can be derived from the B-H characteristic of the material A at the angle formed with the rolling direction.

[0113] Next, in order to reduce the variation in the magnetic flux density of the teeth, the optimal tooth width is determined for each angle with the rolling direction. Figure 7 The tooth width is determined so that the "tooth width" x "tooth magnetic flux density" is substantially constant in each tooth. Here, the tooth width is determined for each torque ratio.

[0114] For example, in Figure 7 In the case of a torque ratio of 60 [%], when the angle with the rolling direction is 0°, the magnetic flux density of the tooth is 1.65 [T], when the angle is 22.5°, the magnetic flux density of the tooth is 1.61 [T], when the angle is 45°, the magnetic flux density of the tooth is 1.55 [T], when the angle is 67.5°, the magnetic flux density of the tooth is 1.56 [T], and when the angle is 90°, the magnetic flux density of the tooth is 1.59 [T]. Therefore, for any of the angles of 0°, 22.5°, 45°, 67.5°, and 90°, the width of the tooth is determined in such a way that "tooth width" × "tooth magnetic flux density" is roughly constant. The width of the tooth determined in this way is called the optimal width.

[0115] Figure 8 This is a table showing the relationship between the torque ratio [%] and the optimal width [mm] of the tooth determined for each angle with the rolling direction.

[0116] For example, in Figure 8 In the case of a torque ratio of 60[%], when the angle with the rolling direction is 0°, the optimal width of the tooth is 5.64[mm], when the angle is 22.5°, the optimal width of the tooth is 5.76[mm], when the angle is 45°, the optimal width of the tooth is 5.99[mm], when the angle is 67.5°, the optimal width of the tooth is 5.96[mm], and when the angle is 90°, the optimal width of the tooth is 5.85[mm]. Here, Figure 7 The "tooth magnetic flux density" when the torque ratio is 60[%], and Figure 8 The product of the "optimal width of the tooth" and each of the angles formed with the rolling direction when the torque ratio is 60 [%] is 9.3, which is substantially constant.

[0117] The stator core is designed by applying the optimal width of the teeth determined in this way to the width of the teeth corresponding to the angle formed with the rolling direction.

[0118] For example, in Figure 8 In the case of a torque ratio of 60[%], the design is performed as follows: Figure 5 The width of the teeth 501a and 501b included in the 0° range (A1) shown is set to 5.64 [mm], the width of the teeth 501c~501e included in the 22.5° range (A2) is set to 5.76 [mm], the width of the teeth 501f~501h included in the 45° range (A3) is set to 5.99 [mm], the width of the teeth 501i~501k included in the 67.5° range (A4) is set to 5.96 [mm], and the width of the teeth 501l and 501m included in the 90° range (A5) is set to 5.85 [mm].

[0119] In addition, in the above Figure 2 As shown in the curve 201 showing the relationship between the angle with the rolling direction and the magnetic properties of the material A, the magnetic flux density in the range of angles 0° to 90° and the magnetic flux density in the range of angles 90° to 180° are roughly symmetrical with the angle 90° as the boundary. Furthermore, in the material A, the magnetic flux density in the range of angles 0° to 180° and the magnetic flux density in the range of angles 180° to 360° are roughly symmetrical with the angle 180° as the boundary.

[0120] therefore, Figure 7The magnetic flux density B[T] of each tooth at the angle with the rolling direction shown in FIG. 1 is not only in the range of 0° with the rolling direction (angle 348.75° to 11.25°: A1), but also Figure 4 The angles 168.75° to 191.25° are also substantially the same, and therefore the width of the teeth included in the angles 168.75° to 191.25° is designed to be substantially the same as the width of the teeth included in the 0° range (A1).

[0121] Likewise, Figure 4 The teeth included in the angles of 146.25° to 168.75°, 191.25° to 213.75°, and 326.25° to 348.75° are also designed to have substantially the same width as the teeth included in the range of 22.5° (11.25° to 33.75°: A2).

[0122] Likewise, Figure 4 The teeth included in the angles of 123.75° to 146.25°, 213.75° to 236.25°, and 303.75° to 326.25° are also designed to have substantially the same width as the teeth included in the 45° range (angle 33.75° to 56.25°: A3).

[0123] Likewise, Figure 4 The teeth included in the angles of 101.25° to 123.75°, 236.25° to 258.75°, and 281.25° to 303.75° are also designed to have substantially the same width as the teeth included in the range of 67.5° (angle 56.25° to 78.75°: A4).

[0124] Likewise, Figure 4 The teeth included in the angle of 258.75° to 281.25° are also designed to have substantially the same width as the teeth included in the range of 90° (78.75° to 101.25°: A5).

[0125] In this way, in the designed stator core, the width of the teeth along the direction of excellent magnetic properties will be smaller than the width of the teeth along the direction of poor magnetic properties. In material A, the so-called teeth along the direction of excellent magnetic properties are not limited to teeth along the angle of 0° with the rolling direction and teeth along the angle of 90° with the rolling direction, but also include teeth located near these teeth. Specifically, in material A, the teeth along the direction of excellent magnetic properties are teeth included in the angle of 348.75° to 11.25°, teeth included in the angle of 168.75° to 191.25°, teeth included in the angle of 78.75° to 101.25°, and teeth included in the angle of 258.75° to 281.25°.

[0126] In addition, in material A, the teeth along the direction of poor magnetic properties are not limited to the teeth along the angle of 45° with the rolling direction, and the teeth along the angle of 135°, 225°, and 315° with the rolling direction, but also include teeth located near these teeth. Specifically, in material A, the teeth along the direction of poor magnetic properties are teeth included in the angle of 33.75° to 56.25°, teeth included in the angle of 123.75° to 146.25°, teeth included in the angle of 213.75° to 236.25°, and teeth included in the angle of 303.75° to 326.25°.

[0127] Fig. 9 This is a table showing the relationship between the iron loss ratio [-] between a stator core whose tooth width is designed to be the optimal width for each torque ratio [%] and a stator core whose tooth width is constant over the entire circumference. The iron loss ratio is a value obtained by dividing the iron loss of the motor of the invention example by the iron loss of the motor of the comparative example, when a motor having a stator core whose tooth width is designed to be the optimal width is taken as the invention example and a motor having a stator core whose tooth width is constant over the entire circumference is taken as the comparative example. Here, the iron loss ratio is calculated for each torque ratio. In addition, the iron loss can be derived by performing electromagnetic field analysis (numerical analysis) under the condition that the motor of the invention example and the motor of the comparative example respectively operate at a rotation speed of 3,000 [rpm] and achieve the above-mentioned torque ratios "%. In addition, it can also be derived by measuring the manufactured motor.

[0128] according to Fig. 9 The results of the iron loss ratio shown in the figure show that when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the iron loss can be suppressed by 0.1[%] to 1.3[%]. On the other hand, when the torque ratio is 100[%], magnetic saturation occurs as described above, and the magnetic flux density of the tooth is constant regardless of the angle with the rolling direction, so the effect of suppressing the iron loss cannot be confirmed.

[0129] In this way, it can be confirmed that by determining the tooth width in a manner such that "tooth width" × "tooth magnetic flux density" is approximately constant in each tooth based on operating conditions such as the torque ratio, the deviation in magnetic flux density can be reduced and iron loss can be suppressed in an area that does not cause magnetic saturation.

[0130] In addition, once the width of the tooth is determined, the stator core actually manufactured cannot change the width of the tooth for each change in the operating conditions such as the torque ratio. Therefore, when designing the stator core, for example, a design device for the stator core selects any one of the multiple operating conditions (multiple torque ratios). In the selected operating condition, the width of the tooth is determined in such a way that the "tooth width" × "tooth magnetic flux density" is constant in each tooth, thereby designing the stator core. As a result, the deviation of the magnetic flux density of the stator core can be reduced in the selected operating condition.

[0131] On the other hand, when the motor with the designed stator core is operated, if the time of operation under the selected operating conditions does not exist or is short, it is impossible to actually reduce the deviation of the magnetic flux density to suppress the iron loss. Therefore, when designing the stator core, it is necessary to consider the operating location of the rotating electrical machine and determine the width of the teeth in advance so as to suppress the iron loss to the greatest extent.

[0132] Hereinafter, two design methods of the stator core will be described. The two design methods may be performed by a stator core design device described later or by a designer of the stator core.

[0133] [The first design method of the stator core]

[0134] The first design method is a method as follows: assuming that a rotating electrical machine having a stator core to be designed is operating, an operating condition with the highest ratio of operating time to total operating time among multiple operating conditions is determined, and an optimal tooth width is determined under the determined operating condition.

[0135] Fig.10 An example of operating data is shown when a rotating electrical machine having a stator core to be designed is assumed to be operating. Specifically, Fig.10 An example of the ratio of the operating time corresponding to the torque ratio in the motor 600 having the stator core to be designed is shown. Here, the operating time refers to the time when the motor 600 rotates. In addition, Fig.10 The operating data shown are obtained before designing the stator core.

[0136] exist Fig.10 In the above example, since the torque ratio of 30% to 50% in the multiple operating conditions is 45% of the operating time, it corresponds to the operating condition with the highest operating time ratio. Figure 6 The average magnetic flux density of the teeth corresponding to the torque ratio of 40% is 1.44 [T peak], to calculate the average magnetic field intensity H [A / m] of the tooth. In the above description of <Determination example of tooth width (teeth with grooves parallel to the radial direction (material A))>, for each torque ratio, as Figure 7 As shown in FIG. 1 , the magnetic flux density B[T] of each tooth at an angle to the rolling direction is calculated, and Figure 8 As shown in FIG. 1 , the optimal width of the tooth is determined for each angle with the rolling direction. On the other hand, here, only the torque ratio 40[%] with the highest operating time ratio is calculated. Figure 7 The magnetic flux density B[T] of each tooth at the angle with the rolling direction is shown. Only for the torque ratio with the highest operating time ratio of 40[%], for Figure 8 Each of the angles shown with the rolling direction determines the optimum width of the tooth.

[0137] Therefore, the optimal width of each tooth is determined to be one. By applying the optimal width determined in this way to the width of the tooth and designing the stator core, it is possible to reduce the variation in magnetic flux density and suppress iron loss under the operating conditions where the proportion of the operating time is the highest.

[0138] [Second design method for stator core]

[0139] The second design method is a method as follows: assuming that a rotating electrical machine having a stator core to be designed is operating, the ratio of the operating time of each of multiple operating conditions is determined, and the tooth width is weighted based on the ratio of the operating time of each of the determined multiple operating conditions.

[0140] In addition, in the second design method, reference is also made to Fig.10 In the second design method, Fig.10 The operating data shown are obtained before designing the stator core.

[0141] In the second design method, similar to the above-mentioned <Example of determining the width of the tooth (teeth with grooves parallel to the radial direction (material A))>, Figure 6 The relationship between the torque ratio and the average magnetic flux density of the teeth is shown, and the Figure 7 The relationship between the torque ratio and the magnetic flux density of each tooth at the angle formed with the rolling direction is shown in FIG. Figure 8 The optimum width of each tooth is shown at an angle to the rolling direction.

[0142] Then, based on Fig.10 The optimal width of each tooth at each angle to the rolling direction is weighted by the ratio of the operating time corresponding to the torque ratio shown. Figure 8For each of the angles with the rolling direction shown, the optimal width of the tooth for each torque ratio is multiplied by the value corresponding to Fig.10 Here, since there are five types of torque ratios, five values ​​can be calculated by multiplying the optimal width of the tooth for each torque ratio by the ratio of the operating time corresponding to the torque ratio. Then, by adding the calculated five values ​​and dividing by 100, the width of the tooth weighted by the ratio of the operating time can be calculated at a predetermined angle with the rolling direction. Similarly, the width of the tooth weighted by the ratio of the operating time is also calculated at other angles with the rolling direction.

[0143] For example, taking the case where the angle with the rolling direction is 0°, Figure 8 In the figure, when the torque ratio is 20[%], 40[%], 60[%], 80[%], and 100[%], the optimal width of the tooth is 5.40[mm], 5.57[mm], 5.64[mm], 5.79[mm], and 5.86[mm], respectively. Fig.10 The ratio of the operating time corresponding to the torque ratio shown is 20 [%], 45 [%], 20 [%], 10 [%], and 5 [%], and five values ​​of 108 [mm·%], 250.65 [mm·%], 112.8 [mm·%], 57.9 [mm·%], and 29.3 [mm·%] are calculated. By adding the five values ​​and dividing by 100 [%], the tooth width weighted by the ratio of the operating time is calculated to be 5.58 [mm] at an angle of 0° with the rolling direction. The tooth width weighted by the ratio of the operating time is also calculated for the angles of 22.5°, 45°, 67.5°, and 90° with the rolling direction.

[0144] Fig.11 is a number representing the angles with the rolling direction, based on Fig.10 The table shows the ratio of the operating time to the weighted tooth width. Fig.10 In the example, the operating time ratio of the torque ratio 30[%] to 50[%] is 45[%], which is the highest operating time ratio. Fig.11 As shown in the figure, the weighted tooth width is calculated. Figure 8 The value shown is close to the optimum width of the teeth when the torque ratio is 40 [%].

[0145] In this way, by designing the stator core using the tooth width weighted according to the ratio of the operating time, it is possible to reduce the variation in magnetic flux density over the entire operating time.

[0146] Here, if Fig.11As shown in FIG. 1 , a motor having a stator core designed with weighted teeth width is used as an invention example, and a motor having a stator core designed with teeth width constant over the entire circumference is used as a comparative example. Fig.10 The ratio of the operating time shown makes the iron loss ratio during operation 0.993, and it can be confirmed that 0.7% of the iron loss can be suppressed. In this way, the stator core can be designed and the rotating electric machine can be constructed by applying the weighted tooth width based on the ratio of the operating time, thereby suppressing the iron loss.

[0147] [How to obtain operation data]

[0148] In the above-mentioned [first design method of a stator core], before designing the stator core, in a rotating electrical machine having the stator core to be designed, it is necessary to predetermine an operating condition having the highest ratio of operating time among a plurality of operating conditions. In addition, in the above-mentioned [second design method of a stator core], before designing the stator core, in a rotating electrical machine having the stator core to be designed, it is necessary to predetermine a ratio of operating time corresponding to an operating condition.

[0149] That is, in order to design the stator core in any of the first design method and the second design method, it is necessary to obtain in advance operation data assuming that the rotating electrical machine including the stator core to be designed is operating.

[0150] Here, the operating data is roughly divided into two types: planned data and actual performance data.

[0151] The so-called planning data refers to data that predetermines the action of the rotating electrical machine and plans the operation time corresponding to the operation conditions. For example, the rotating electrical machine used in the predetermined production equipment often continues a certain action or repeats a certain action. In such a rotating electrical machine, the planning data can be obtained in advance. By obtaining the planning data, it is possible to determine the information of the operation condition with the highest operation time ratio, or determine the operation time ratio corresponding to the operation condition.

[0152] On the other hand, the so-called performance data refers to data obtained by accumulating the operating time corresponding to the operating conditions when the same type of rotating motor is in operation as the actual performance. For example, the rotating motor used in HEV (Hybrid Electric Vehicle) or EV (Electric Vehicle) cannot obtain the planned data because the operating time corresponding to the operating conditions varies depending on the user (operator). In such a case, it is possible to obtain the performance data in advance by collecting a large amount of data on the actual vehicle operation and analyzing the collected big data. For example, it is also possible to obtain data by analyzing the operating time corresponding to the operating conditions of the rotating motor when the vehicle is running in the JC08 mode, which is the fuel consumption measurement standard in Japan. By obtaining the performance data, it is possible to determine the information of the operating condition with the highest proportion of the operating time, or to determine the proportion of the operating time corresponding to the operating conditions.

[0153] In this way, by obtaining operation data using planned data or actual performance data, it is possible to determine the operation condition with the highest operation time ratio among multiple operation conditions before designing the stator core, or to determine the operation time ratio corresponding to the operation condition.

[0154] <Example of determining the tooth width (teeth with grooves parallel to the radial direction (material B))>

[0155] Next, when the electromagnetic steel sheet is material B and the stator core of the embedded permanent magnet synchronous motor is designed, an example of determining the width of the tooth in such a way that the above-mentioned "tooth width" × "tooth magnetic flux density" is approximately constant in each tooth is described. In addition, the same contents as those in the above-mentioned <Example of determining the width of the tooth (teeth with slots parallel to the radial direction (material A))> will be appropriately omitted.

[0156] Here, for the Figure 4 The rotation speed of the motor 400 shown is set to 3,000 [rpm], and the relationship between the operating condition (torque ratio) and the average magnetic flux density of the teeth is analyzed when the width of the teeth is constant over the entire circumference of the stator core 421. Figure 6 same.

[0157] according to Figure 6 The average magnetic flux density of the teeth shown is used to calculate the average magnetic field intensity H [A / m] of the teeth. Next, based on the material properties of material B, the magnetic flux density B [T] of each tooth at an angle to the rolling direction when excited with the average magnetic field intensity of the teeth is calculated.

[0158] Fig.12This is a table showing the relationship between the torque ratio [%] and the magnetic flux density B [T] of each tooth at each angle with the rolling direction.

[0159] like Fig.12 As shown in the figure, when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the magnetic flux density of each tooth at an angle to the rolling direction will deviate. In addition, when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the magnetic flux density of the tooth at an angle of 45° to the rolling direction is larger, and the magnetic flux density of the tooth at an angle of 0° and 90° to the rolling direction is smaller. This tendency is consistent with the following tendency: Figure 2 The B50 ratio is large at an angle of 45° with the rolling direction as shown by the curve 202 of material B shown in FIG. 1 , and the B50 ratio is small at an angle of 0° and 90° with the rolling direction. Fig.12 As shown, when the torque ratio is 100[%], the magnetic flux density of the tooth is constant regardless of the angle with the rolling direction because of magnetic saturation.

[0160] Next, based on Fig.12 The magnetic flux density of the tooth at each of the angles with the rolling direction shown is determined so that the “tooth width”דtooth magnetic flux density” becomes substantially constant in each tooth.

[0161] Fig.13 This is a table showing the relationship between the torque ratio [%] and the optimal width of the tooth [mm] determined for each angle with the rolling direction. The determined optimal width of the tooth is applied to the width of the tooth corresponding to the angle with the rolling direction to design the stator core.

[0162] In this way, in the designed stator core, the width of the teeth along the direction of excellent magnetic properties will be smaller than the width of the teeth along the direction of poor magnetic properties. In material B, the so-called teeth along the direction of excellent magnetic properties are not limited to teeth along the angle of 45° with the rolling direction, and teeth along the angle of 135°, 225°, and 315° with the rolling direction, but also include teeth located near these teeth. Specifically, in material B, the teeth along the direction of poor magnetic properties are teeth included in the angle of 33.75° to 56.25°, teeth included in the angle of 123.75° to 146.25°, teeth included in the angle of 213.75° to 236.25°, and teeth included in the angle of 303.75° to 326.25°.

[0163] In addition, in material B, the teeth along the direction with poor magnetic properties are not limited to the teeth along the angles of 0° and 90° with the rolling direction, but also include teeth located near these teeth. Specifically, in material B, the teeth along the direction with excellent magnetic properties are teeth included in the angles of 348.75° to 11.25°, teeth included in the angles of 168.75° to 191.25°, teeth included in the angles of 78.75° to 101.25°, and teeth included in the angles of 258.75° to 281.25°.

[0164] Fig.14 This is a table showing the relationship between the iron loss ratio [-] between a stator core in which the tooth width is designed to be the optimum width and a stator core in which the tooth width is constant over the entire circumference for each torque ratio [%].

[0165] according to Fig.14 The results of the iron loss ratio shown in the figure show that when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the iron loss can be suppressed by 0.6[%] to 6.4[%]. On the other hand, when the torque ratio is 100[%], magnetic saturation occurs, and the magnetic flux density of the tooth is constant regardless of the angle with the rolling direction, so the effect of suppressing the iron loss cannot be confirmed.

[0166] In this way, it can be confirmed that by determining the tooth width in a manner such that "tooth width" × "tooth magnetic flux density" is approximately constant in each tooth based on operating conditions such as the torque ratio, the deviation in magnetic flux density can be reduced and iron loss can be suppressed in an area that does not cause magnetic saturation.

[0167] Next, similarly to the above-mentioned [Second Design Method of Stator Core], based on Fig.10 The optimal width of the tooth for each angle with the rolling direction is weighted by the ratio of the operating time according to the torque ratio shown.

[0168] Fig.15 is a number representing the angles with the rolling direction, based on Fig.10 The table shows the ratio of the operating time to the weighted tooth width.

[0169] Here, if Fig.15 As shown in FIG. 1 , a motor having a stator core designed with weighted teeth width is used as an invention example, and a motor having a stator core designed with teeth width constant over the entire circumference is used as a comparative example. Fig.10 The ratio of the operating time shown makes the iron loss ratio during operation 0.958, and it can be confirmed that the iron loss can be suppressed by 4.2[%].

[0170] <Example of determining the width of the tooth (teeth parallel to the radial direction (material A))>

[0171] Next, an example of determining the width of a tooth in a manner that the above-mentioned "tooth width" x "tooth magnetic flux density" is approximately constant in each tooth when the electromagnetic steel sheet is made of material A and the stator core of an induction motor is designed will be described. In addition, the same contents as those in the above-mentioned "Example of determining the width of a tooth (teeth with slots parallel to the radial direction (material A))" will be appropriately omitted. In an induction motor, the teeth of the stator core are as follows: Figure 3 As shown in (a), they are parallel along the radial direction.

[0172] Fig.16 1 is a diagram showing an example of the structure of the motor 1600 before the width of the teeth is determined, that is, the width of each tooth is constant over the entire circumference. Fig.16 , a cross section of the motor 1600 cut perpendicularly to the axis O thereof is shown.

[0173] exist Fig.16 In the figure, the motor 1600 is an induction motor having a rotor 1610 and a stator 1620 .

[0174] The rotor 1610 is coaxially mounted on the rotating shaft 1630 (axis O). The rotor 1610 has a plurality of windings. Fig.16 As shown, the number of poles of the motor 1600 is 4. In addition, the outer diameter of the rotor 1610 is 134 [mm].

[0175] The stator 1620 has a stator core 1621 and a winding 1622. The outer diameter of the stator 1620 is 220 [mm], and the inner diameter of the stator 1620 is 136 [mm]. The number of slots of the stator core 1621 is 60. In addition, the winding 1622 is distributed winding.

[0176] Fig.17 Yes Fig.16 The enlarged view is an extracted and enlarged view of a portion of the stator core 1621 that forms an angle of 0° to 90° with the rolling direction. Here, tooth 1701a among teeth 1701a to 1701p of the stator core 1621 is located at an angle of 0° with the rolling direction, and 1 / 2 of the width of the tooth is omitted in the illustration. In addition, tooth 1701p among teeth 1701a to 1701p is located at an angle of 90° with the rolling direction, and 1 / 2 of the width of the tooth is omitted in the illustration. In addition, each tooth is as shown in FIG. Figure 3 As shown in (a), the teeth are parallel to the radial direction. The width of each tooth is 4 mm.

[0177] Here, in Fig.182 shows the results of analyzing the relationship between the operating conditions (torque ratio) and the average magnetic flux density of the teeth when the rotation speed of the motor 1600 is 3,000 [rpm] and the width of the teeth is constant over the entire circumference of the stator core 1621.

[0178] Fig.18 represents the torque ratio [%] and the average magnetic flux density B [T peak ] is a diagram of the relationship between .

[0179] according to Fig.18 The average magnetic flux density of the teeth shown is used to calculate the average magnetic field intensity H [A / m] of the teeth. Next, based on the material properties of material A, the magnetic flux density B [T] of each tooth at an angle to the rolling direction when excited with the average magnetic field intensity of the teeth is calculated.

[0180] Fig.19 This is a table showing the relationship between the torque ratio [%] and the magnetic flux density B [T] of each tooth at each angle with the rolling direction.

[0181] like Fig.19 As shown in the figure, when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the magnetic flux density of each tooth at an angle to the rolling direction will deviate. In addition, when the torque ratio is 40[%], 60[%], and 80[%], the magnetic flux density of the teeth at an angle of 0° and 90° to the rolling direction is larger, and the magnetic flux density of the teeth at an angle of 45° to the rolling direction is smaller. This tendency is consistent with the following tendency: Figure 2 The B50 ratio is larger at the angles 0° and 90° with the rolling direction as shown in the curve 201 of material A shown in FIG. 1 , and the B50 ratio is smaller at the angle 45° with the rolling direction. Fig.19 As shown, when the torque ratio is 100[%], the magnetic flux density of the tooth is substantially constant regardless of the angle formed with the rolling direction due to magnetic saturation.

[0182] Next, based on Fig.19 The magnetic flux density of the tooth at each of the angles with the rolling direction shown is determined so that the “tooth width”דtooth magnetic flux density” becomes substantially constant in each tooth.

[0183] Fig. 20 This is a table showing the relationship between the torque ratio [%] and the optimal width [mm] of the tooth determined for each angle with the rolling direction.

[0184] For example, in Fig. 20In the case of a torque ratio of 60 [%], when the angle with the rolling direction is 0°, the optimal width of the tooth is 3.85 [mm], when the angle is 22.5°, the optimal width of the tooth is 3.96 [mm], when the angle is 45°, the optimal width of the tooth is 4.08 [mm], when the angle is 67.5°, the optimal width of the tooth is 4.06 [mm], and when the angle is 90°, the optimal width of the tooth is 3.96 [mm]. Here, for each angle with the rolling direction, Fig.19 The "tooth magnetic flux density" when the torque ratio is 60[%] and Fig. 20 The product of multiplying the "optimal width of the tooth" when the torque ratio is 60 [%] is 6.7, which is approximately constant.

[0185] The stator core is designed by applying the optimal tooth width determined in this way to the width of the tooth corresponding to the angle formed with the rolling direction.

[0186] For example, in Fig. 20 In the case of a torque ratio of 60[%], the design is performed as follows: Fig.17 The width of the teeth 1701a~1701b included in the 0° range (A1) shown is set to 3.85 [mm], the width of the teeth 1701c~1701f included in the 22.5° range (A2) is set to 3.96 [mm], the width of the teeth 1701g~1701j included in the 45° range (A3) is set to 4.08 [mm], the width of the teeth 1701k~1701n included in the 67.5° range (A4) is set to 4.06 [mm], and the width of the teeth 1701o~1701p included in the 90° range (A5) is set to 3.96 [mm].

[0187] also, Fig.19 The magnetic flux density B[T] of each tooth at the angle with the rolling direction shown in FIG. 1 is not only in the range of 0° with the rolling direction (angle 11.25° to 33.75: A1), but also Fig.16 The angles 168.75° to 191.25° are also substantially the same, and therefore the teeth included in the angles 168.75° to 191.25° are also designed to have substantially the same width as the teeth included in the 0° range (A1).

[0188] Likewise, Fig.16 The teeth included in the angles of 146.25° to 168.75°, 191.25° to 213.75°, and 326.25° to 348.75° are also designed to have substantially the same width as the teeth included in the 22.5° range (A2).

[0189] Likewise, Fig.16The teeth included in the angles 123.75° to 146.25°, 213.75° to 236.25°, and 303.75° to 326.25° are also designed to have substantially the same width as the teeth included in the 45° range (angle 33.75° to 56.25°: A3).

[0190] Likewise, Fig.16 The teeth included in the angles of 101.25° to 123.75°, 236.25° to 258.75°, and 281.25° to 303.75° are also designed to have substantially the same width as the teeth included in the range of 67.5° (angle 56.25° to 78.75°: A4).

[0191] Likewise, Fig.16 The teeth included in the angle of 258.75° to 281.25° are also designed to have substantially the same width as the teeth included in the range of 90° (78.75° to 101.25°: A5).

[0192] In addition, the tooth 1701c located between the 0° range (A1) and the 22.5° range (A2) is set to the 22.5° range, but it can also be set to the 0° range. In addition, the tooth 1701n located at the boundary between the 67.5° range (A4) and the 90° range (A5) is set to the 67.5° range, but it can also be set to the 90° range.

[0193] Fig.21 This is a table showing the relationship between the iron loss ratio [-] between a stator core in which the tooth width is designed to be the optimum width and a stator core in which the tooth width is constant over the entire circumference for each torque ratio [%].

[0194] according to Fig.21 The results of the iron loss ratio shown in the figure show that when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the iron loss can be suppressed by 0.1[%] to 1.4[%]. On the other hand, when the torque ratio is 100[%], magnetic saturation occurs, and the magnetic flux density of the tooth is almost constant regardless of the angle with the rolling direction, so the effect of suppressing the iron loss cannot be confirmed.

[0195] Next, similarly to the above-mentioned [Second Design Method of Stator Core], based on Fig.10 The optimal width of the tooth for each angle with the rolling direction is weighted by the ratio of the operating time according to the torque ratio shown.

[0196] Fig. 22 is a number representing the angles with the rolling direction, based on Fig.10 The table shows the ratio of the operating time to the weighted tooth width.

[0197] Here, if Fig. 22 As shown in FIG. 1 , a motor having a stator core designed with weighted teeth width is used as an invention example, and a motor having a stator core designed with teeth width constant over the entire circumference is used as a comparative example. Fig.10 The ratio of the operating time shown makes the iron loss ratio during operation 0.995, and it can be confirmed that the iron loss can be suppressed by 0.5[%].

[0198] <Example of determining the width of the tooth (teeth parallel to the radial direction (material B))>

[0199] Next, an example of determining the width of the tooth in a manner such that the above-mentioned "tooth width" x "tooth magnetic flux density" is substantially constant in each tooth when the electromagnetic steel sheet is made of material B and the stator core of the induction motor is designed will be described. In addition, the description of the same contents as those in the above-mentioned <Example of determining the width of the tooth (teeth parallel to the radial direction (material A))> will be appropriately omitted.

[0200] Here, for the Fig.16 The rotation speed of the motor 1600 shown is set to 3,000 [rpm], and the relationship between the operating condition (torque ratio) and the average magnetic flux density of the teeth is analyzed when the width of the teeth is constant over the entire circumference of the stator core 1621. Fig.18 same.

[0201] according to Fig.18 The average magnetic flux density of the teeth shown is used to calculate the average magnetic field intensity H [A / m] of the teeth. Next, based on the material properties of material B, the magnetic flux density B [T] of each tooth at an angle to the rolling direction when excited with the average magnetic field intensity of the teeth is calculated.

[0202] Fig.23 This is a table showing the relationship between the torque ratio [%] and the magnetic flux density B [T] of each tooth at each angle with the rolling direction.

[0203] like Fig.23 As shown in the figure, under any torque ratio, the magnetic flux density of each tooth at an angle to the rolling direction has a deviation. In addition, under any torque ratio, the magnetic flux density of the tooth at an angle of 45° to the rolling direction is larger, and the magnetic flux density of the tooth at an angle of 0° and 90° to the rolling direction is smaller. This tendency is consistent with the following tendency: Figure 2 The material B shown has a larger B50 ratio at an angle of 45° to the rolling direction as shown by curve 202, and a smaller B50 ratio at angles of 0° and 90° to the rolling direction.

[0204] Next, based on Fig.23 The magnetic flux density of the tooth at each of the angles with the rolling direction shown is determined so that the “tooth width”דtooth magnetic flux density” becomes substantially constant in each tooth.

[0205] Fig.24 This is a table showing the relationship between the torque ratio [%] and the optimal width [mm] of the tooth determined for each angle with the rolling direction.

[0206] Fig.25 This is a table showing the relationship between the iron loss ratio [-] between a stator core in which the tooth width is designed to be the optimum width and a stator core in which the tooth width is constant over the entire circumference for each torque ratio [%].

[0207] according to Fig.25 The results of the iron loss ratio shown in the figure show that when the torque ratio is 20[%], 40[%], 60[%], and 80[%], the iron loss can be suppressed by 1.1[%] to 5.6[%]. On the other hand, when the torque ratio is 100[%], magnetic saturation occurs, and the magnetic flux density of the tooth is almost constant regardless of the angle with the rolling direction, so the effect of suppressing the iron loss cannot be confirmed.

[0208] In this way, it can be confirmed that by determining the width of each tooth in a manner such that "tooth width" × "tooth magnetic flux density" is approximately constant in each tooth based on operating conditions such as the torque ratio, the deviation in magnetic flux density can be reduced and iron loss can be suppressed in an area that does not cause magnetic saturation.

[0209] Next, similarly to the above-mentioned [Second Design Method of Stator Core], based on Fig.10 The optimal width of the tooth for each angle with the rolling direction is weighted by the ratio of the operating time according to the torque ratio shown.

[0210] Fig.26 is a number representing the angles with the rolling direction, based on Fig.10 The table shows the ratio of the operating time to the weighted tooth width.

[0211] Here, if Fig.26 As shown in FIG. 1 , a motor having a stator core designed with weighted teeth width is used as an invention example, and a motor having a stator core designed with teeth width constant over the entire circumference is used as a comparative example. Fig.10 The ratio of the operating time shown makes the iron loss ratio during operation 0.972, and it can be confirmed that the iron loss can be suppressed by 2.8[%].

[0212] <Design device of stator core>

[0213] Next, the case where the above-mentioned [first design method for a stator core] and [second design method for a stator core] are implemented using a stator core design device 2700 is described. The hardware of the stator core design device 2700 is implemented by using, for example, an information processing device having a CPU, ROM, RAM, HDD, and various hardware, or dedicated hardware.

[0214] Fig. 27 This is a diagram showing an example of the mechanical structure of the stator core design device 2700.

[0215] The stator core design device 2700 has an operation data acquisition unit 2701, an operation condition / operation ratio determination unit 2702, an average magnetic flux density acquisition unit 2703, an evaluation magnetic flux density calculation unit 2704, an average magnetic field strength calculation unit 2705, a tooth magnetic flux density acquisition unit 2706, a tooth width determination unit 2707, and a stator core design unit 2708.

[0216] Fig.28 This is a flowchart showing an example of processing of the stator core design device 2700. Fig.28 The flowchart of FIG. 27 shows an example of realizing the above-mentioned [first design method of a stator core] by the stator core design device 2700. In addition, the description similar to the above description will be omitted as appropriate.

[0217] In S101, the operation data acquisition unit 2701 acquires the operation data of the rotating electrical machine when the rotating electrical machine including the stator core to be designed is operated. That is, the operation data acquisition unit 2701 acquires the operation data assuming that the rotating electrical machine including the stator core to be designed is operated.

[0218] As described above, the operation data includes planned data and actual data. In the case of a rotating electrical machine whose operation is predetermined, the operation data acquisition unit 2701 acquires the planned data. In the case of a rotating electrical machine of the same type that has already been operated and accumulated as actual data, the operation data acquisition unit 2701 acquires the actual data. In addition, the operation data acquisition unit 2710 may acquire at least one of the planned data and the actual data without being limited to any one of the planned data and the actual data. By the processing of S101, for example, Fig.10 The operating data shown.

[0219] In S102, the operating condition / operation ratio determination unit 2702 determines the operating condition having the highest operating time ratio among the plurality of operating conditions based on the operating data acquired in S101. Fig.10The operating data shown in the figure determines that the torque ratio of 30[%] to 50[%], that is, the torque ratio of 40[%] is determined as the operating condition with the highest operating time ratio.

[0220] In S103, the average magnetic flux density acquisition unit 2703 acquires information on the average magnetic flux density of the teeth corresponding to the operating conditions determined in S102. Specifically, the average magnetic flux density acquisition unit 2703 acquires the average magnetic flux density of the teeth by performing an electromagnetic field analysis (numerical analysis) based on Maxwell's equations or measuring the induced voltage using a probe winding and integrating the induced voltage under the operating conditions determined in S102 and when the width of the teeth over the entire circumference of the stator core is constant.

[0221] Through the processing of S103, for example, Figure 6 As shown in the relationship between the torque ratio and the average magnetic flux density of the teeth, the average magnetic flux density of the teeth corresponding to the operating condition with the highest operating time ratio, that is, the torque ratio of 40[%] is 1.44[T peak ].

[0222] In S104, the average magnetic field intensity calculation unit 2705 calculates the intensity of the average magnetic field of the tooth based on the information of the average magnetic flux density of the tooth acquired in S103. The intensity of the average magnetic field of the tooth can be calculated based on the relative magnetic permeability of the electromagnetic steel sheet.

[0223] In S105, the tooth magnetic flux density acquisition unit 2706 acquires information on the magnetic flux density of the tooth when excited with the intensity of the average magnetic field of the tooth calculated in S104. Specifically, the tooth magnetic flux density acquisition unit 2706 acquires the magnetic flux density B[T] of the tooth at each angle formed with the rolling direction when excited with the intensity of the average magnetic field of the tooth based on the material properties, more specifically, based on the B-H characteristics of each angle formed with the rolling direction of the electromagnetic steel sheet.

[0224] Through the processing of S105, for example, Figure 7 Under the operating condition with the highest operating time ratio shown, i.e. a torque ratio of 40[%], the tooth magnetic flux densities are 1.51[T], 1.47[T], 1.42[T], 1.42[T] and 1.44[T] at angles of 0°, 22.5°, 45°, 67.5° and 90° to the rolling direction, respectively.

[0225] In S106, the tooth width determination unit 2707 determines the width of the tooth so that the product of the "tooth width" and the "tooth magnetic flux density" obtained in S105 is substantially constant in each tooth. The tooth width determined in this way is the optimal width of the tooth.

[0226] Through the processing of S106, for example, Figure 8As shown, under the operating condition with the highest operating time ratio, i.e., a torque ratio of 40[%], the optimal tooth widths are determined to be 5.57[mm], 5.72[mm], 5.95[mm], 5.93[mm], and 5.85[mm] at angles of 0°, 22.5°, 45°, 67.5°, and 90° to the rolling direction, respectively.

[0227] In S107, the stator core design unit 2708 applies the determined optimal width of the teeth to the width of the teeth corresponding to the angle formed with the rolling direction, thereby designing the stator core.

[0228] Through the processing of S107, for example, the optimal width of the tooth at the angles of 0°, 22.5°, 45°, 67.5°, and 90° with the rolling direction is applied to Figure 4 The stator core is designed based on the width of the teeth included in the 0° range (2 A1s), 22.5° range (4 A2s), 45° range (4 A3s), 67.5° range (4 A4s), and 90° range (2 A5s) shown.

[0229] In this way, the stator core design device 2700 designs the stator core, thereby reducing the deviation of the magnetic flux density and suppressing the iron loss under the operating condition where the proportion of the operating time is the highest.

[0230] In addition, in the above description, the following case is described, but the present invention is not limited to this case: in S102, the operating condition with the highest operating time ratio among the plurality of operating conditions is determined, in S103, the information of the average magnetic flux density of the teeth corresponding to the determined operating condition is obtained, and in S104, the intensity of the average magnetic field of the teeth is calculated based on the information of the average magnetic flux density of the teeth. For example, by omitting the processing of S101 to S104 and inputting the predetermined magnetic field intensity by the operator of the stator core design device 2700, the tooth magnetic flux density acquisition unit 2706 of the stator core design device 2700 can acquire the information of the intensity of the average magnetic field of the teeth. In this case, in S105, the tooth magnetic flux density acquisition unit 2706 can acquire the information of the input intensity of the average magnetic field of the teeth, and acquire the magnetic flux density of the teeth based on the acquired information of the intensity of the average magnetic field of the teeth.

[0231] Fig.29 This is a flowchart showing an example of processing of the stator core design device 2700. Fig.29 The flowchart of FIG. 2 shows an example of implementing the above-mentioned [second design method of stator core] by the stator core design device 2700. Fig.28 The description of the same processing as in the flowchart will be omitted as appropriate.

[0232] In S201, the operation data acquisition unit 2701 acquires the operation data of the rotating electrical machine when the rotating electrical machine having the stator core to be designed is operated. This process is the same as the process of S101. Fig.10 The operating data shown.

[0233] In S202, the operating condition / operation ratio determination unit 2702 determines the ratio of the operating time of each of the plurality of operating conditions based on the operating data acquired in S101. Fig.10 The operating data shown is used to determine the ratio of the operating time corresponding to the torque ratio.

[0234] In S203, the average magnetic flux density acquisition unit 2703 acquires information on the average magnetic flux density of the teeth corresponding to each of the plurality of operating conditions. Specifically, the average magnetic flux density acquisition unit 2703 acquires the average magnetic flux density of the teeth for each of the plurality of operating conditions in the following manner: for each of the plurality of operating conditions, when the width of the teeth is constant over the entire circumference of the stator core, an electromagnetic field analysis (numerical analysis) based on Maxwell's equations is performed, or an induced voltage is measured using a probe winding and the induced voltage is integrated.

[0235] Through the processing of S203, for example, Figure 6 As shown in FIG. 1 , the average magnetic flux density of the teeth is obtained for each torque ratio, as shown in FIG. 1 .

[0236] In S204, the average magnetic field intensity calculation unit 2705 calculates the intensity of the average magnetic field of the teeth for each of the plurality of operating conditions based on the information of the average magnetic flux density of the teeth corresponding to each of the plurality of operating conditions obtained in S203. The intensity of the average magnetic field of the teeth can be calculated based on the relative magnetic permeability of the electromagnetic steel sheet.

[0237] In S205, the tooth magnetic flux density acquisition unit 2706 acquires information on the magnetic flux density of the teeth for each of the plurality of operating conditions when the magnetic field is excited with the intensity of the average magnetic field of the teeth for each of the plurality of operating conditions calculated in S204. Specifically, the tooth magnetic flux density acquisition unit 2706 acquires the magnetic flux density B[T] of the teeth at each angle formed with the rolling direction when the magnetic field is excited with the intensity of the average magnetic field of the teeth for each of the plurality of operating conditions based on the material properties, more specifically, based on the B-H characteristics of each angle formed with the rolling direction of the electromagnetic steel sheet.

[0238] Through the processing of S205, for example, Figure 7As shown, for each torque ratio, the magnetic flux density of the tooth is obtained at angles of 0°, 22.5°, 45°, 67.5°, and 90° with the rolling direction.

[0239] In S206, the tooth width determination unit 2707 calculates the tooth width for each of a plurality of operating conditions so that the product of the "tooth width" and the "tooth magnetic flux density" obtained in S205 is substantially constant in each tooth. The tooth width calculated in this way is the optimal tooth width.

[0240] Through the processing of S206, for example, Figure 8 As shown, for each torque ratio, the optimum width of the tooth is calculated at the angles of 0°, 22.5°, 45°, 67.5°, and 90° with the rolling direction.

[0241] In S207 , the tooth width determination unit 2707 weights the optimal tooth width for each of the plurality of operating conditions calculated in S206 based on the ratio of the operating time for each of the plurality of operating conditions determined in S202 , and determines the weighted tooth width.

[0242] Through the processing of S207, for example, Fig.11 As shown in FIG. 1 , the tooth width is determined by weighting based on the ratio of the operation time.

[0243] In S208, the stator core design unit 2708 applies the weighted tooth width to the tooth width corresponding to the angle formed with the rolling direction, thereby designing the stator core.

[0244] Through the processing of S208, for example, the widths of the teeth weighted at the angles of 0°, 22.5°, 45°, 67.5°, and 90° with the rolling direction are applied to Figure 4 The stator core is designed based on the width of the teeth included in the 0° range (2 A1s), 22.5° range (4 A2s), 45° range (4 A3s), 67.5° range (4 A4s), and 90° range (2 A5s) shown.

[0245] In this manner, the stator core design device 2700 designs the stator core, thereby reducing the variation in magnetic flux density over the entire operation time and suppressing the iron loss.

[0246] In addition, Fig.29 In the flowchart of , in S207 , the case where the optimal width of the teeth for each of the plurality of operating conditions is weighted based on the ratio of the operating time for each of the plurality of operating conditions is described, but the present invention is not limited to this case.

[0247] Fig.30This is a flowchart showing an example of processing of the stator core design device 2700. Fig.30 The flowchart of shows an example of a method different from the above-mentioned [Second Design Method of Stator Core] implemented by the stator core design device 2700. Fig.28 Flowchart and Fig.29 The same processing as in the flowchart will be omitted as appropriate.

[0248] In S301, the operation data acquisition unit 2701 acquires the operation data of the rotating electrical machine when the rotating electrical machine having the stator core to be designed is operated. This process is the same as the process of S101 and S201. Fig.10 The operating data shown.

[0249] In S302, the operating condition / operation ratio determination unit 2702 determines the ratio of the operation time for each of the plurality of operating conditions based on the operating data acquired in S301. This process is the same as the process in S202.

[0250] In S303, the average magnetic flux density acquisition unit 2703 acquires information on the average magnetic flux density of the teeth corresponding to each of the plurality of operating conditions. This process is the same as that of S203. Figure 6 As shown in FIG. 1 , the average magnetic flux density of the teeth is obtained for each torque ratio, as shown in FIG. 1 .

[0251] In S304, the evaluation magnetic flux density calculation unit 2704 calculates the evaluation magnetic flux density of the tooth weighted based on the ratio of the operating time determined in S302, based on the information of the average magnetic flux density of the tooth corresponding to each of the multiple operating conditions obtained in S303. The evaluation magnetic flux density is the magnetic flux density of the tooth obtained by weighting the average magnetic flux density of the tooth based on the ratio of the operating time. Specifically, the evaluation magnetic flux density calculation unit 2704 can calculate the evaluation magnetic flux density by multiplying each torque ratio by the average magnetic flux density of the tooth and the ratio of the operating time, adding the multiplied values ​​and dividing by 100.

[0252] For example, in Figure 6 The relationship between the torque ratio and the average magnetic flux density of the teeth is shown in FIG. Fig.10 In the case of the operating data shown in FIG. 1 , the evaluation magnetic flux density Bv of the tooth [T peak ] is calculated as follows: Substitute (1.22[T peak ]×20[%]+1.44[T peak ]×45[%]+1.59[T peak ]×20[%]+1.82[Tpeak ]×10[%]+2.04[T peak ]×5[%]) divided by 100.

[0253] In S305, the average magnetic field intensity calculation unit 2705 calculates the intensity of the average magnetic field of the tooth based on the evaluation magnetic flux density of the tooth calculated in S304. The intensity of the average magnetic field of the tooth can be calculated based on the relative magnetic permeability of the electromagnetic steel sheet.

[0254] In S306, the tooth magnetic flux density acquisition unit 2706 acquires information on the magnetic flux density of the tooth when the tooth is excited with the intensity of the average magnetic field of the tooth calculated in S305. This process is the same as that in S105.

[0255] In S307, the tooth width determination unit 2707 determines the tooth width so that the product of the "tooth width" and the "tooth magnetic flux density" obtained in S306 is substantially constant in each tooth. This process is the same as that in S106.

[0256] Through the processing of S307, for example, Fig.11 As shown in FIG. 1 , the tooth width is determined by weighting based on the ratio of the operation time.

[0257] In S308, the stator core design unit 2708 applies the determined tooth width to the tooth width corresponding to the angle formed with the rolling direction, thereby designing the stator core. This process is the same as that of S107.

[0258] In this way, the stator core design device 2700 designs the stator core, thereby reducing the deviation of the magnetic flux density throughout the entire operation time and suppressing the iron loss. In addition, the reduction process can be sought by calculating the tooth evaluation magnetic flux density weighted by the average magnetic flux density of the tooth based on the ratio of the operation time, and performing subsequent processing based on the calculated tooth evaluation magnetic flux density.

[0259] As described above, according to the present embodiment, by determining the width of the tooth so that “tooth width”דtooth magnetic flux density” is substantially constant in each tooth, it is possible to reduce the variation in magnetic flux density and suppress iron loss.

[0260] In addition, as described above, the so-called each tooth may be, for example, a tooth at predetermined intervals such as 0°, 22.5°, 45°, 67.5°, and 90° with the rolling direction, or may be all teeth. In addition, the so-called substantially constant is not limited to the case of being completely constant, and "substantially constant" includes a range that can better suppress iron loss compared to the comparative example. Specifically, the so-called substantially constant means that the difference between the maximum and minimum values ​​of "tooth width" × "tooth magnetic flux density" is within ±1%, preferably within ±0.5%. As described above, the following case is explained: for each of the angles with the rolling direction, Figure 7 The "tooth magnetic flux density" when the torque ratio is 60[%] is Figure 8 The product of multiplying the "optimal width of the tooth" when the torque ratio is 60[%] is 9.3, which is roughly constant. Specifically, when the angle with the rolling direction is 0°, the magnetic flux density of the tooth is 1.65[T]×the optimal width of the tooth is 5.64[mm]=9.306≈9.3, when the angle with the rolling direction is 22.5°, the magnetic flux density of the tooth is 1.61[T]×the optimal width of the tooth is 5.76[mm]=9.2736≈9.3, and when the angle with the rolling direction is 45°, the magnetic flux density of the tooth is 1.55 [T] × optimal width of the tooth 5.99 [mm] = 9.2845 ≈ 9.3, when the angle with the rolling direction is 67.5°, the magnetic flux density of the tooth is 1.56 [T] × optimal width of the tooth 5.96 [mm] = 9.2976 ≈ 9.3, when the angle with the rolling direction is 90°, the magnetic flux density of the tooth is 1.59 [T] × optimal width of the tooth 5.85 [mm] = 9.3015 ≈ 9.3. The difference between the maximum and minimum values ​​in this case is 9.306 ÷ 9.2736 ≈ 1.0035, so "roughly constant" is within 0.5%. In addition, when 9.25 to 9.34 is allowed as the rounding range of 9.3, 9.34 ÷ 9.25 ≈ 1.0097, so "roughly constant" is within 1%.

[0261] Next, the material B in the above-mentioned electromagnetic steel sheet can suppress the iron loss more than the material A.

[0262] Here, the electromagnetic steel sheet of material B will be described.

[0263] In the following description, a direction that forms an angle of 45° with the rolling direction is referred to as a direction that is inclined 45° from the rolling direction, and a direction that forms an angle of 135° with the rolling direction is referred to as a direction that is inclined 135° from the rolling direction. In addition, a direction that forms an angle of θ° with the rolling direction is referred to as a direction that is inclined θ° from the rolling direction. Thus, a direction that forms an angle of θ° with the rolling direction and a direction that is inclined θ° from the rolling direction have the same meaning.

[0264] First, the chemical components of a non-oriented electrical steel sheet as an example of Material B (hereinafter referred to as the non-oriented electrical steel sheet of the present embodiment) and the steel material used in its manufacturing method will be described. In the following description, the unit of the content of each element contained in the non-oriented electrical steel sheet or the steel material of the present embodiment, namely "%", means "% by mass" unless otherwise specified. In addition, for the numerical limit range described with "~" sandwiched, the lower limit value and the upper limit value are included in this range. For the value shown as "less than" or "exceeding", the value is not included in the numerical range. The non-oriented electrical steel sheet and the steel material are chemical components in which ferrite-austenite phase transformation (hereinafter referred to as α-γ phase transformation) can occur, and have the following chemical components: containing C: 0.0100% or less, Si: 1.50% to 4.00%, sol.Al: 0.0001% to 1.0%, S: 0.0100% or less, N: 0.0100% or less, one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: a total of 2.50% to 5.00%, Sn: 0.000% to 0.400%, Sb: 0.000% to 0.400%, P: 0.000% to 0.400%, and one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: a total of 0.0000% to 0.0100%, and the balance is composed of Fe and impurities. Furthermore, the contents of Mn, Ni, Co, Pt, Pb, Cu, Au, Si, and sol.Al satisfy the predetermined conditions described later. As impurities, impurities contained in raw materials such as ores or scraps, and impurities contained in the manufacturing process can be exemplified.

[0265] <<C: 0.0100% or less>>

[0266] C increases iron loss or causes magnetic aging. Therefore, the lower the C content, the better. Such a phenomenon is significant when the C content exceeds 0.0100%. Therefore, the C content is set to 0.0100% or less. The reduction of the C content also contributes to the uniform improvement of magnetic properties in all directions within the sheet surface. In addition, the lower limit of the C content is not particularly limited, but based on the cost of decarburization treatment during refining, it is preferably set to 0.0005% or more.

[0267] <<Si: 1.50% to 4.00%>>

[0268] Si increases the resistance, thereby reducing eddy current loss and lowering iron loss, or increases the yield ratio, thereby improving the blanking processability of the iron core. When the Si content is less than 1.50%, these effects cannot be obtained sufficiently. Therefore, the Si content is set to 1.50% or more. On the other hand, when the Si content exceeds 4.00%, the magnetic flux density decreases, or the blanking processability decreases due to excessive increase in hardness, or cold rolling becomes difficult. Therefore, the Si content is set to 4.00% or less.

[0269] <<sol.Al: 0.0001% - 1.0%>>

[0270] sol.Al increases the resistance, thereby reducing eddy current loss and lowering iron loss. sol.Al also contributes to the improvement of the relative magnitude of the magnetic flux density B50 with respect to the saturation magnetic flux density. Here, the so-called magnetic flux density B50 refers to the magnetic flux density when excited with a magnetic field strength of 5000 A / m. When the sol.Al content is less than 0.0001%, these effects cannot be obtained sufficiently. In addition, Al also has a desulfurization promotion effect in steelmaking. Therefore, the sol.Al content is set to 0.0001% or more. On the other hand, when the sol.Al content exceeds 1.0%, the magnetic flux density decreases, or the yield ratio decreases, thereby reducing the blanking processability. Therefore, the sol.Al content is set to 1.0% or less.

[0271] <<S: 0.0100% or less>>

[0272] S is not an essential element and is included in steel as an impurity, for example. Due to the precipitation of fine MnS, S hinders recrystallization and grain growth during annealing. Therefore, the lower the S content, the better. The increase in iron loss and the decrease in magnetic flux density caused by such hindrance of recrystallization and grain growth are significant when the S content exceeds 0.0100%. Therefore, the S content is set to 0.0100% or less. In addition, the lower limit of the S content is not particularly limited, but based on the cost of desulfurization treatment during refining, it is preferably set to 0.0003% or more.

[0273] <<N: 0.0100% or less>>

[0274] Similar to C, N deteriorates the magnetic properties, so the lower the N content, the better. Therefore, the N content is set to 0.0100% or less. In addition, the lower limit of the N content is not particularly limited, but based on the cost of denitrification treatment during refining, it is preferably set to 0.0010% or more.

[0275] <<One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: in total 2.50% - 5.00%>>

[0276] These elements are necessary for the α-γ transformation to occur, so they need to be contained in a total of 2.50% or more. On the other hand, if the total exceeds 5.00%, the cost will increase and the magnetic flux density may also decrease. Therefore, the total content of these elements is set to 5.00% or less.

[0277] In addition, as a condition for the occurrence of α-γ phase transformation, the following condition should be further satisfied. That is, when the Mn content (mass %) is recorded as [Mn], the Ni content (mass %) is recorded as [Ni], the Co content (mass %) is recorded as [Co], the Pt content (mass %) is recorded as [Pt], the Pb content (mass %) is recorded as [Pb], the Cu content (mass %) is recorded as [Cu], the Au content (mass %) is recorded as [Au], the Si content (mass %) is recorded as [Si], and the sol.Al content (mass %) is recorded as [sol.Al], it is preferred that the following formula (1) is satisfied in terms of mass %.

[0278] ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])>0%··· (1)

[0279] When the above-mentioned formula (1) is not satisfied, the α-γ phase transition does not occur, and thus the magnetic flux density becomes low.

[0280] <<Sn:0.000%~0.400%、Sb:0.000%~0.400%、P:0.000%~0.400%> >

[0281] Sn and Sb improve the texture after cold rolling and recrystallization, thereby increasing its magnetic flux density. Therefore, these elements may be contained as needed, but when they are contained excessively, the steel will become brittle. Therefore, the Sn content and the Sb content are both set to 0.400% or less. In addition, in order to ensure the hardness of the steel plate after recrystallization, P may be contained, but when it is contained excessively, it will cause the brittleness of the steel. Therefore, the P content is set to 0.400% or less. In the case of imparting further effects such as magnetic properties as described above, it is preferred to contain one or more selected from the group consisting of 0.020% to 0.400% Sn, 0.020% to 0.400% Sb and 0.020% to 0.400% P.

[0282] <<One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.0000% to 0.0100% in total>>

[0283] Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd react with S in the molten steel during casting to form sulfide or oxysulfide or precipitates of both. Hereinafter, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd are sometimes collectively referred to as "coarse precipitate-forming elements". The particle size of the precipitates of the coarse precipitate-forming elements is about 1 μm to 2 μm, which is much larger than the particle size of fine precipitates such as MnS, TiN and AlN (about 100 nm). Therefore, these fine precipitates will adhere to the precipitates of the coarse precipitate-forming elements, making it difficult to hinder the recrystallization and grain growth during intermediate annealing. In order to fully obtain these effects, the total amount of these elements is preferably 0.0005% or more. However, when the total content of these elements exceeds 0.0100%, sulfides or oxysulfides or the total content of both will be excessive, and recrystallization and grain growth during intermediate annealing will be inhibited. Therefore, the content of coarse precipitate-forming elements is set to 0.0100% or less in total.

[0284] <<Texture>>

[0285] Next, the texture of the non-oriented electrical steel sheet of the present embodiment will be described. The details of the manufacturing method will be described later. The non-oriented electrical steel sheet of the present embodiment has a chemical composition that can undergo an α-γ phase transformation. The structure is refined by rapid cooling immediately after the final rolling in hot rolling, thereby becoming a structure in which {100} grains grow. As a result, the clustering strength of the {100}<011> orientation of the non-oriented electrical steel sheet of the present embodiment will be 5 to 30, and the magnetic flux density B50 in the direction of 45° relative to the rolling direction will be particularly high. In this way, the magnetic flux density will be high in a specific direction, but overall, a relatively high magnetic flux density will be obtained in all directions on average. When the clustering strength of the {100}<011> orientation is less than 5, the clustering strength of the {111}<112> orientation that reduces the magnetic flux density will be high, and the magnetic flux density will be reduced overall. Furthermore, a production method in which the cluster strength of the {100}<011> orientation exceeds 30 requires thickening the hot-rolled sheet, which causes a problem of difficulty in production.

[0286] The clustering intensity of the {100}<011> orientation can be measured by X-ray diffraction or electron backscatter diffraction (EBSD). Since the reflection angle of X-rays and electron beams from the sample is different for each crystal orientation, the crystal orientation intensity can be obtained by using the reflection intensity and the like based on a randomly oriented sample. The clustering intensity of the {100}<011> orientation of the preferred non-oriented electromagnetic steel sheet of this embodiment is 5 to 30 in terms of the X-ray random intensity ratio. At this time, the crystal orientation can also be measured by EBSD, and the value converted into the X-ray random intensity ratio can be used.

[0287] <<Thickness>>

[0288] Next, the thickness of the non-oriented electromagnetic steel sheet of the present embodiment is described. The thickness of the non-oriented electromagnetic steel sheet of the present embodiment is 0.50 mm or less. When the thickness exceeds 0.50 mm, excellent high-frequency iron loss cannot be obtained. Therefore, the thickness is set to 0.50 mm or less.

[0289] <<Magnetic properties>>

[0290] Next, the magnetic properties of the non-oriented electromagnetic steel sheet of the present embodiment are described. When investigating the magnetic properties, the magnetic flux density of the non-oriented electromagnetic steel sheet of the present embodiment, i.e., the value of B50, is measured. In the manufactured non-oriented electromagnetic steel sheet, one side and the other side of the rolling direction cannot be distinguished. Therefore, in the present embodiment, the so-called rolling direction refers to the two directions of one side and the other side. When the value of B50 in the rolling direction is recorded as B50L, the value of B50 in the direction inclined by 45° from the rolling direction is recorded as B50D1, the value of B50 in the direction inclined by 90° from the rolling direction is recorded as B50C, and the value of B50 in the direction inclined by 135° from the rolling direction is recorded as B50D2, it can be observed that B50D1 and B50D2 are the highest, and B50L and B50C are the lowest.

[0291] Here, for example, considering the distribution of all orientations (0° to 360°) of the magnetic flux density with the clockwise (or counterclockwise) direction as the positive direction, when the rolling direction is set to 0° (one direction) and 180° (the other direction), B50D1 will have B50 values ​​of 45° and 225°, and B50D2 will have B50 values ​​of 135° and 315°. Similarly, B50L will have B50 values ​​of 0° and 180°, and B50C will have B50 values ​​of 90° and 270°. The B50 value of 45° is strictly consistent with the B50 value of 225°, and the B50 value of 135° is strictly consistent with the B50 value of 315°. However, it is sometimes not easy to make the magnetic properties of B50D1 and B50D2 the same during actual manufacturing, so there may be situations where they are strictly inconsistent. Similarly, the B50 value at 0° is strictly consistent with the B50 value at 180°, the B50 value at 90° is strictly consistent with the B50 value at 270°, and B50L and B50C may not be strictly consistent. In the non-oriented electrical steel sheet of this embodiment, the average value of B50D1 and B50D2, and the average value of B50L and B50C satisfy the following equations (2) and (3).

[0292] (B50D1+B50D2) / 2>1.7T···(2)

[0293] (B50D1+B50D2) / 2>(B50L+B50C) / 2···(3)

[0294] Thus, when the magnetic flux density is measured, the average value of 50D1 and B50D2 is greater than 1.7 T as shown in formula (2), and high anisotropy of the magnetic flux density is confirmed as shown in formula (3).

[0295] Furthermore, in addition to satisfying the formula (1), it is preferable that the anisotropy of the magnetic flux density is higher than that of the formula (3), as shown in the following formula (4).

[0296] (B50D1+B50D2) / 2>1.1×(B50L+B50C) / 2···(4)

[0297] Furthermore, as shown in the following formula (5), it is preferable that the anisotropy of the magnetic flux density is higher.

[0298] (B50D1+B50D2) / 2>1.2×(B50L+B50C) / 2···(5)

[0299] Furthermore, as shown in the following formula (6), the average value of B50D1 and B50D2 is preferably 1.8T or more.

[0300] (B50D1+B50D2) / 2>1.8T···(6)

[0301] In addition, the above-mentioned 45° is a theoretical value. In actual manufacturing, it is sometimes not easy to make it consistent with 45°, so strictly speaking, values ​​inconsistent with 45° should also be included. This also applies to 0°, 90°, 135°, 180°, 225°, 270°, and 315°.

[0302] The magnetic flux density can be measured by cutting out a 55 mm square sample from a direction of 45°, 0°, etc. with respect to the rolling direction and using a single plate magnetic measurement device.

[0303] <<Manufacturing method>>

[0304] Next, an example of a method for manufacturing the non-oriented electromagnetic steel sheet of the present embodiment is described. When manufacturing the non-oriented electromagnetic steel sheet of the present embodiment, for example, hot rolling, cold rolling (first cold rolling), intermediate annealing (first annealing), skin pass rolling (second cold rolling), final annealing (third annealing), stress relief annealing (second annealing), etc. are performed.

[0305] First, the steel material is heated and hot rolled. The steel material is, for example, a steel billet produced by general continuous casting. Rough rolling and finish rolling of hot rolling are performed at a temperature in the γ region (above the Ar1 temperature). That is, hot rolling is performed in a manner such that the finish rolling temperature of the finish rolling is above the Ar1 temperature and the coiling temperature exceeds 250°C and is below 600°C. Thus, by subsequent cooling, austenite transforms into ferrite, thereby refining the structure. If the subsequent cold rolling is performed in a refined state, since the occurrence of protruding recrystallization (hereinafter referred to as expansion) becomes easy, it is possible to make the {100} grains that are generally difficult to grow easier to grow.

[0306] In addition, when manufacturing the non-oriented electromagnetic steel sheet of the present embodiment, the temperature at the final pass of the finish rolling (finish rolling temperature) is further set to be above the Ar1 temperature, and the coiling temperature is set to be above 250°C and below 600°C. The crystal structure is refined by transformation from austenite to ferrite. By refining the crystal structure in this way, expansion can be more easily caused by subsequent cold rolling and intermediate annealing.

[0307] Thereafter, the hot-rolled sheet is directly coiled without annealing, and the hot-rolled steel sheet is cold-rolled after pickling. It is preferred that the reduction ratio during cold rolling is 80% to 95%. If the reduction ratio is less than 85%, expansion is difficult to occur. If the reduction ratio exceeds 95%, although the {100} grains are easier to grow through subsequent expansion, the hot-rolled steel sheet needs to be thickened, which makes hot-rolling difficult and the operation becomes difficult. The reduction ratio of cold rolling is more preferably 86% or more. If the reduction ratio of cold rolling is above 86%, expansion is more likely to occur.

[0308] After the cold rolling is completed, intermediate annealing is continued. When manufacturing the non-oriented electromagnetic steel sheet of this embodiment, intermediate annealing is performed at a temperature that does not transform into austenite. That is, it is preferred that the temperature of the intermediate annealing is lower than the Ac1 temperature. By performing intermediate annealing in this way, expansion occurs, making it easier for {100} grains to grow. In addition, the time of intermediate annealing is preferably 5 seconds to 60 seconds.

[0309] After the intermediate annealing is completed, skin-pass rolling is performed next. If skin-pass rolling and annealing are performed in the state where expansion occurs in the manner described, the {100} grains will further grow starting from the portion where the expansion occurs. This is because, through skin-pass rolling, the {100}<011> grains have the property of being difficult to accumulate strain, while the {111}<112> grains have the property of being easy to accumulate strain. In the subsequent annealing, the {100}<011> grains with less strain use the strain difference as the driving force to erode the {111}<112> grains. This erosion phenomenon caused by the strain difference as the driving force is called strain-induced grain boundary migration (hereinafter referred to as SIBM). The reduction rate of skin-pass rolling is preferably 5% to 25%. If the reduction rate is less than 5%, the strain amount is too small, SIBM does not occur in the subsequent annealing, and the {100}<011> grains cannot grow larger. On the other hand, if the reduction rate exceeds 25%, the strain amount is too large and recrystallization nucleation (hereinafter referred to as nucleation) occurs, in which new grains are generated from {111}<112> grains. Since most of the grains generated in this nucleation are {111}<112> grains, the magnetic properties deteriorate.

[0310] After skin-pass rolling, final annealing is performed to release strain and improve workability. The final annealing is also set to a temperature that does not transform into austenite, so that the temperature of the final annealing is lower than the Ac1 temperature. By performing such a final annealing, the {100}<011> grains cannibalize the {111}<112> grains, which can improve the magnetic properties. In addition, during the final annealing, the time to reach the temperature of 600°C ~ Ac1 is within 1200 seconds. If this annealing time is too short, the strain generated during skin-pass rolling will still remain to a large extent, and warping will occur when punching into complex shapes. On the other hand, if the annealing time is too long, the grains become too coarse, the edge collapse becomes larger during punching, and the punching accuracy cannot be achieved.

[0311] After the final annealing is completed, the non-oriented electromagnetic steel sheet is formed to make it into the desired steel component. Furthermore, in order to remove the strain generated by forming the steel component composed of the non-oriented electromagnetic steel sheet (for example, punching), the steel component is subjected to stress relief annealing. In this embodiment, in order to cause SIBM to occur at a temperature lower than Ac1 and the grain size can be coarse, the temperature of stress relief annealing is set to, for example, about 800°C and the time of stress relief annealing is set to about 2 hours. By stress relief annealing, the magnetic properties can be improved.

[0312] Regarding the non-oriented electrical steel sheet (steel component) of the present embodiment, in the manufacturing method, high B50 of the formula (1) and excellent anisotropy of the formula (2) are obtained mainly by performing finish rolling at a temperature of Ar1 or higher in the hot rolling process. Furthermore, by setting the reduction ratio to about 10% in the skin pass rolling process, even better anisotropy of the formula (4) is obtained.

[0313] It should be noted that in this embodiment, the Ar1 temperature is obtained from the thermal expansion change of the steel material (steel plate) during cooling at an average cooling rate of 1°C / sec. In addition, in this embodiment, the Ac1 temperature is obtained from the thermal expansion change of the steel material (steel plate) during heating at an average heating rate of 1°C / sec.

[0314] As described above, the steel member formed of the non-oriented electromagnetic steel sheet according to the present embodiment can be manufactured.

[0315] Next, the non-oriented electromagnetic steel sheet according to the present embodiment will be specifically described by showing an example. The example shown below is only an example of the non-oriented electromagnetic steel sheet, and the non-oriented electromagnetic steel sheet is not limited to the following example.

[0316] <<First Embodiment>>

[0317] By casting the molten steel, an ingot having the composition shown in the following Tables 1 and 2 is produced. The left side of the formula here represents the value of the left side of the formula (1). Thereafter, the produced ingot is heated to 1150°C for hot rolling and rolled to a plate thickness of 2.5 mm. Furthermore, after the finish rolling is completed, water cooling is performed and the hot-rolled steel plate is coiled. At this time, the temperature at the final pass stage of the finish rolling (finishing rolling temperature) is 830°C, which is higher than the Ar1 temperature. It should be noted that for No. 108, which did not undergo γ-α phase transformation, the finishing rolling temperature was set to 850°C. In addition, the coiling temperature is carried out under the conditions shown in Table 1.

[0318] Next, the hot rolled steel sheet was pickled to remove oxide scale, and then rolled at the reduction ratio after cold rolling shown in Table 1. Furthermore, intermediate annealing was performed at 700°C for 30 seconds in a non-oxidizing atmosphere. Then, rolling was performed at the second cold rolling (skin pass rolling) reduction ratio shown in Table 1.

[0319] Next, to check the magnetic properties, after the second cold rolling (skin smooth rolling), the final annealing was performed at 800°C for 30 seconds, and a 55 mm square sample was made by shearing. After 2 hours of stress relief annealing at 800°C, the magnetic flux density B50 was measured. The measured samples were 55 mm square samples collected in two directions of 0° and 45° in the rolling direction. Then, these two samples were measured, and the magnetic flux density B50 at 0°, 45°, 90°, and 135° relative to the rolling direction was recorded as B50L, B50D1, B50C, and B50D2, respectively.

[0320]

Table 1

[0321]

[0322]

Table 2

[0323]

[0324] The underline in Tables 1 and 2 indicates conditions outside the scope of the present invention. Inventive Examples No. 101 to No. 107, No. 109 to No. 111, and No. 114 to No. 130 all have good values ​​of magnetic flux density B50 in the 45° direction and on average over the entire circumference. However, since No. 116 and No. 127 exceed the appropriate coiling temperature, the magnetic flux density B50 is slightly low. Since the cold rolling reduction rate of No. 129 and No. 130 is low, the magnetic flux density B50 is slightly lower than that of No. 118 with the same composition and coiling temperature. On the other hand, since the Si concentration of Comparative Example No. 108 is high, the value on the left side of the formula is below 0, and it is a composition that does not undergo α-γ phase transformation, so the magnetic flux density B50 is relatively low. Since the skin smooth rolling rate of Comparative Example No. 112 is low, the {100}<011> strength is less than 5, and the magnetic flux density B50 is relatively low. The {100}<011> strength of Comparative Example No. 113 is greater than 30, which is beyond the scope of the present invention. Since the hot-rolled sheet of No. 113 is as thick as 7 mm, it has the disadvantage of being difficult to handle.

[0325] <<Second Embodiment>>

[0326] By casting molten steel, an ingot with the composition shown in Table 3 is produced. After that, the produced ingot is heated to 1150°C for hot rolling and rolled to a plate thickness of 2.5 mm. Furthermore, after the finish rolling is completed, water cooling is performed and the hot rolled steel plate is coiled. At this time, the finishing rolling temperature of the final pass stage of the finish rolling is 830°C, which is higher than the Ar1 temperature.

[0327] Next, the hot-rolled steel sheet is pickled to remove the oxide scale and cold rolled to a thickness of 0.385 mm. Then, intermediate annealing is performed in a non-oxidizing environment, and the temperature of the intermediate annealing is controlled to achieve a recrystallization rate of 85%. Then, a second cold rolling (skin pass rolling) is performed to a thickness of 0.35 mm.

[0328] Next, in order to detect the magnetic properties, after the second cold rolling (skin smooth rolling), a final annealing is performed at 800°C for 30 seconds. After a 55 mm square sample is made by shearing, a stress relief annealing is performed at 800°C for 2 hours, and the magnetic flux density B50 and iron loss W10 / 400 are measured. The magnetic flux density B50 is measured in the same order as in the first embodiment. On the other hand, the iron loss W10 / 400 is measured as the energy loss (W / kg) generated by the sample when an AC magnetic field of 400 Hz is applied in order to achieve a maximum magnetic flux density of 1.0 T. The iron loss is the average value of the results measured at 0°, 45°, 90°, and 135° relative to the rolling direction.

[0329]

Table 3

[0330]

[0331]

Table 4

[0332]

[0333] No. 201 to No. 214 are all invention examples, and all have good magnetic properties. In particular, No. 202 to No. 204 have higher magnetic flux density B50 than No. 201 and No. 205 to No. 214, and lower iron loss W10 / 400 than No. 201 to No. 204.

[0334] As mentioned above, although this invention was demonstrated together with various embodiment, this invention is not limited only to these embodiment, and it can change etc. within the scope of this invention.

[0335] In the above description, the case where the operating condition is the torque ratio is described, but the present invention is not limited to this case, and the operating condition may be the rotation speed ratio or the torque ratio for each rotation speed ratio.

[0336] Industrial Availability

[0337] According to the present invention, it is possible to reduce the variation in magnetic flux density and suppress iron loss. Therefore, the present invention has high industrial applicability.

[0338] Description of Reference Numerals

[0339] 100: Rotating motor

[0340] 110: Rotor

[0341] 120: Stator

[0342] 121a~121p: Tooth

[0343] 122: Yoke

[0344] 130: Rotation axis

[0345] 400: Electric motor

[0346] 410: Rotor

[0347] 411: Permanent magnet

[0348] 421: Stator core

[0349] 422: Winding

[0350] 501a~501m:Stator

[0351] 1600: Electric motor

[0352] 1610: Rotor

[0353] 1621: Stator core

[0354] 1622: Winding

[0355] 1701a~1701p:Stator

[0356] 2700: Design device of stator core

[0357] 2701: Operation data acquisition unit

[0358] 2702: Operation condition / operation ratio determination unit

[0359] 2703: Average magnetic flux density acquisition unit

[0360] 2704: Evaluation of magnetic flux density calculation unit

[0361] 2705: Average magnetic field strength calculation unit

[0362] 2706: Tooth magnetic flux density acquisition unit

[0363] 2707: Tooth width determination unit

[0364] 2708: Stator Core Design Department

Claims

1. A stator core comprising a plurality of stacked electromagnetic steel sheets, characterized in that: Among the plurality of teeth of the stator core, the width of the teeth along the direction with excellent magnetic characteristics is smaller than the width of the teeth along the direction with poor magnetic characteristics. The stator core is formed by laminating rolled electromagnetic steel plates; The electromagnetic steel sheet has the following chemical composition: In terms of mass%, it contains C: 0.0100% or less, Si: 1.50% to 4.00%, Sol.Al: 0.0001%~1.0%, S: 0.0100% or less, N: 0.0100% or less, One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au: 2.50% to 5.00% in total, Sn: 0.000%~0.400%, Sb: 0.000%~0.400%, P: 0.000% to 0.400%, and One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: 0.0000% to 0.0100% in total, When the Mn content is expressed as [Mn] in mass %, the Ni content is expressed as [Ni] in mass %, the Co content is expressed as [Co] in mass %, the Pt content is expressed as [Pt] in mass %, the Pb content is expressed as [Pb] in mass %, the Cu content is expressed as [Cu] in mass %, the Au content is expressed as [Au] in mass %, the Si content is expressed as [Si] in mass %, and the sol.Al content is expressed as [sol.Al] in mass %, the following formula (1) is satisfied: ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])>0%··· (1) The remaining part is composed of Fe and impurities; When the value of B50 in the rolling direction is denoted as B50L, the value of B50 in the direction inclined at 45° from the rolling direction is denoted as B50D1, the value of B50 in the direction inclined at 90° from the rolling direction is denoted as B50C, and the value of B50 in the direction inclined at 135° from the rolling direction is denoted as B50D2, the following equations (2) and (3) are satisfied, the X-ray random intensity ratio of {100}<011> is 5 or more and less than 30, the plate thickness is 0.50 mm or less, (B50D1+B50D2) / 2>1.7T···(2) (B50D1+B50D2) / 2>1.1×(B50L+B50C) / 2···(3) The direction with excellent magnetic properties is the direction with an angle of 45° with the rolling direction, and the direction with poor magnetic properties is the direction with an angle of 0° and 90° with the rolling direction; The width of the teeth along the direction at an angle of 45° to the rolling direction is smaller than either the width of the teeth along the direction at an angle of 0° to the rolling direction or the width of the teeth along the direction at an angle of 90° to the rolling direction.

2. A stator core comprising a plurality of stacked electromagnetic steel sheets, characterized in that: Among the plurality of teeth of the stator core, the width of the teeth along the direction with excellent magnetic characteristics is smaller than the width of the teeth along the direction with poor magnetic characteristics. The stator core is formed by laminating rolled electromagnetic steel plates; The electromagnetic steel sheet has the following chemical composition: In terms of mass%, it contains C: 0.0100% or less, Si: 1.50% to 4.00%, Sol.Al: 0.0001%~1.0%, S: 0.0100% or less, N: 0.0100% or less, One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au: 2.50% to 5.00% in total, Sn: 0.000%~0.400%, Sb: 0.000%~0.400%, P: 0.000% to 0.400%, and One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd: 0.0000% to 0.0100% in total, When the Mn content is expressed as [Mn] in mass %, the Ni content is expressed as [Ni] in mass %, the Co content is expressed as [Co] in mass %, the Pt content is expressed as [Pt] in mass %, the Pb content is expressed as [Pb] in mass %, the Cu content is expressed as [Cu] in mass %, the Au content is expressed as [Au] in mass %, the Si content is expressed as [Si] in mass %, and the sol.Al content is expressed as [sol.Al] in mass %, the following formula (1) is satisfied: ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])>0%···(1) The remaining part is composed of Fe and impurities; When the value of B50 in the rolling direction is denoted as B50L, the value of B50 in the direction inclined at 45° from the rolling direction is denoted as B50D1, the value of B50 in the direction inclined at 90° from the rolling direction is denoted as B50C, and the value of B50 in the direction inclined at 135° from the rolling direction is denoted as B50D2, the following equations (4) and (5) are satisfied, the X-ray random intensity ratio of {100}<011> is 5 or more and less than 30, the plate thickness is 0.50 mm or less, (B50D1+B50D2) / 2>1.8T···(4) (B50D1+B50D2) / 2>(B50L+B50C) / 2···(5) The direction with excellent magnetic properties is the direction with an angle of 45° with the rolling direction, and the direction with poor magnetic properties is the direction with an angle of 0° and 90° with the rolling direction; The width of the teeth along the direction at an angle of 45° to the rolling direction is smaller than either the width of the teeth along the direction at an angle of 0° to the rolling direction or the width of the teeth along the direction at an angle of 90° to the rolling direction.

3. The stator core according to claim 1 or 2, characterized in that: In the teeth of the stator core, The difference between the maximum value and the minimum value of the product of the width of the tooth of the stator core and the magnetic flux density of the tooth when excited with a predetermined magnetic field intensity, obtained in each tooth, is within ±1%.

4. The stator core according to claim 1 or 2, characterized in that: Satisfies the following formula (6), (B50D1+B50D2) / 2>1.2×(B50L+B50C) / 2···(6).

5. The stator core according to claim 1 or 2, characterized in that: The electromagnetic steel sheet contains, by mass%, 0.020% to 0.400% of Sn or 0.020% to 0.400% of Sb.

6. A rotating electrical machine, characterized in that: It comprises the stator core as claimed in any one of claims 1 to 5.

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