Stator core and rotating electric machine

Abstract

A stator core (21) provided with a plurality of divided cores (30) is configured by stacking core pieces (40) made of electromagnetic steel sheets, the electromagnetic steel sheets being prescribed electromagnetic steel sheets, and either of the radial direction of teeth (41) of the core pieces (40) of at least one of the plurality of divided cores (30) and the extension direction of a core back (42) is along a direction in which the magnetic properties of the electromagnetic steel sheets are excellent.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a stator core and a rotary electric machine. It is particularly suitable for a stator core having a plurality of divided cores.

[0002] This application claims priority based on Japanese Patent Application No. 2019-206648 filed on November 15, 2019, and the contents thereof are hereby incorporated by reference. BACKGROUND

[0003] As a stator core (core) of a rotary electric machine, a core in which a plurality of divided cores are arranged in the circumferential direction is known.

[0004] In Patent Literature 1, the core of the motor is divided by a division surface into laminated core pieces, and the laminated core pieces are composed of a unidirectional electromagnetic steel sheet or a bidirectional electromagnetic steel sheet. It is disclosed that the winding is wound on the laminated core pieces with an insulating portion therebetween, and the laminated core pieces are laminated while determining the easy magnetization direction for each laminated core piece. According to such a motor, the magnetic flux within the laminated core pieces always flows in the easy magnetization direction of the anisotropic electromagnetic steel sheet, and the change in the direction of the magnetic flux flowing in the pole teeth or the gap at the time of rotation is small, whereby it is possible to reduce the iron loss, the excitation current, the cogging torque, the distortion of the induced voltage, and the torque ripple.

[0005] Patent Literature 2 discloses a motor having a stator core in which a plurality of laminated cores having a tooth portion in which a stator extends in the radial direction are arranged in the circumferential direction. The laminated core has a plurality of core pieces in the form of a plate laminated in the plate thickness direction. The core pieces are composed of a non-directional electromagnetic steel sheet, and the rolling direction of the core pieces has a tilt with respect to the radial direction. In addition, it is disclosed that the laminated core is made by laminating core pieces having the same tilt, and the tilts of at least one pair of laminated cores adjacent in the circumferential direction are opposite to each other. According to such a motor, it is possible to reduce the cogging torque and the torque ripple.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: Japanese Patent Application Laid-Open No. 8-47185

[0009] Patent Literature 2: International Publication No. 2017 / 090571 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] However, neither of Patent Literature 1 and Patent Literature 2 makes any research on electromagnetic steel sheets. Therefore, in the conventional stator core having a plurality of divided cores, there is room for improvement in improving the magnetic properties.

[0012] The present application aims to improve the magnetic characteristics of a stator core having a plurality of divided cores.

[0013] Technical means for solving the technical problem

[0014] To solve the problem, the present application adopts the following configuration.

[0015] (1) The stator core of one aspect of the present application is a stator core having a plurality of divided cores, the plurality of divided cores being configured by laminating core pieces made of an electromagnetic steel sheet, the electromagnetic steel sheet having the following chemical composition: containing, in 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, one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total 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: total 0.0000% to 0.0100%, when the Mn content is [Mn] in mass%, the Ni content is [Ni] in mass%, the Co content is [Co] in mass%, the Pt content is [Pt] in mass%, the Pb content is [Pb] in mass%, the Cu content is [Cu] in mass%, the Au content is [Au] in mass%, the Si content is [Si] in mass%, and the sol. Al content is [sol. Al] in mass%, the following formula (1) is satisfied, the remaining portion is composed of Fe and impurities, when the value of B50 in the rolling direction is B50L, the value of B50 in the direction inclined by 45° from the rolling direction is B50D1, the value of B50 in the direction inclined by 90° from the rolling direction is B50C, and the value of B50 in the direction inclined by 135° from the rolling direction is B50D2, the following formula (2) and formula (3) are satisfied, the X-ray random intensity ratio of {100}<011> is 5 or more and less than 30, the sheet thickness is 0.50 mm or less, and either one of the radial direction of the teeth of the core piece of at least one of the plurality of divided cores and the extension direction of the core back is along the direction in which the magnetic characteristics of the electromagnetic steel sheet are excellent.

[0016] ([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au]) - ([Si] + [sol. Al]) > 0%... (1)

[0017] (B50D1 + B50D2) / 2 > 1.7 T... (2)

[0018] (B50D1+B50D2) / 2 > (B50L+B50C) / 2... (3)

[0019] Here, the magnetic flux density B50 refers to the magnetic flux density when excitation is performed at a magnetic field strength of 5000 A / m.

[0020] (2) The stator core described in the above (1) can also satisfy the following formula (4).

[0021] (B50D1+B50D2) / 2 > 1.1 x (B50L+B50C) / 2... (4)

[0022] (3) The stator core described in the above (1) can also satisfy the following formula (5).

[0023] (B50D1+B50D2) / 2 > 1.2 x (B50L+B50C) / 2... (5)

[0024] (4) The stator core described in the above (1) can also satisfy the following formula (6).

[0025] (B50D1+B50D2) / 2 > 1.8 T... (6)

[0026] (5) In the stator core described in the above (1), the direction in which the magnetic properties of the electromagnetic steel sheet are excellent can be a direction in which the angle with respect to the rolling direction of the electromagnetic steel sheet is 45° and 135°, the radial direction of the tooth can be along a direction in which the angle with respect to the rolling direction is either one of 45° and 135°, and the extension direction of the core back can be along a direction in which the angle with respect to the rolling direction is the other of 45° and 135°.

[0027] (6) In the stator core described in any one of the above (1) to (5), the plurality of divided cores can be such that, in the core pieces of all the divided cores, either one of the radial direction of the tooth and the extension direction of the core back is along the direction in which the magnetic properties of the electromagnetic steel sheet are excellent.

[0028] (7) In the stator core described in any one of the above (1) to (5), the plurality of divided cores can each have a tooth portion, and the width of the tooth portion along the direction in which the magnetic properties are excellent can be narrower than the width of the tooth portion not along the direction in which the magnetic properties are excellent.

[0029] (8) In the stator core described in the above (7), the product of the width of the tooth portion and the magnetic flux density of the tooth portion when excitation is performed at a prescribed magnetic field strength can be substantially constant for each tooth portion of the plurality of divided cores.

[0030] (9) A rotating electric machine according to an aspect of the present application includes the stator core according to any one of (1) to (8) above.

[0031] Effects of the Invention

[0032] According to the above aspect of the present application, the magnetic characteristics of the stator core including a plurality of divided cores can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 FIG. 1 is a diagram showing one example of the configuration of a rotating electric machine.

[0034] Figure 2 FIG. 3 is a diagram showing one example of the configuration of a divided core.

[0035] Figure 3 FIG. 5 is a diagram showing one example of the configuration of a core piece.

[0036] Figure 4 FIG. 9 is a graph showing one example of the relationship between the ratio of B50 and the angle with the rolling direction.

[0037] Figure 5 FIG. 11 is a graph showing one example of the relationship between the ratio of W15 / 50 and the angle with the rolling direction.

[0038] Figure 6 FIG. 13 is a graph showing one example of the relationship between the ratio of W15 / 100 and the angle with the rolling direction.

[0039] Figure 7 FIG. 15 is a graph showing one example of the relationship between the rolling direction and the direction in which the magnetic characteristics are most excellent.

[0040] Figure 8 FIG. 17 is a diagram for explaining a mold according to an embodiment of the present application.

[0041] Figure 9 FIG. 19 is a diagram for explaining the width of a tooth portion.

[0042] Figure 10 FIG. 21 is a diagram for explaining a mold according to a modification. DETAILED DESCRIPTION

[0043] <Example of electromagnetic steel sheet used in divided core>

[0044] First, an electromagnetic steel sheet used in the divided core of the embodiment described later will be described.

[0045] Here, the chemical components of the non-oriented electromagnetic steel sheet of the present embodiment and the steel material used in the manufacturing method thereof, which are one example of the electromagnetic steel sheet used in the divided core as an embodiment, are described. In the following description, the "%" as a unit of the content of each element contained in the non-oriented electromagnetic steel sheet or the steel material of the present embodiment means "mass %" unless otherwise specified. In addition, in the numerical range defined by the values recited with "to", the lower limit value and the upper limit value are included in the range. In the numerical value expressed by "less than" or "more than", the value is not included in the numerical range. The non-oriented electromagnetic steel sheet and the steel material are of a chemical composition capable of generating ferrite-austenite phase transformation (hereinafter referred to as α-γ phase transformation), and have the following chemical composition: 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: total 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: total 0.0000% to 0.0100%, and the remainder consisting of Fe and impurities. Furthermore, the contents of Mn, Ni, Co, Pt, Pb, Cu, Au, Si, and sol. Al satisfy the prescribed conditions described later. As the impurities, impurities contained in ores or waste materials, impurities contained in the manufacturing process can be exemplified.

[0046] <<C: 0.0100% or less>>

[0047] C increases the iron loss or causes magnetic aging. Therefore, the lower the content of C, the more preferable. Such a phenomenon is significant when the content of C exceeds 0.0100%. Therefore, the content of C is set to 0.0100% or less. The reduction of the content of C also contributes to the uniform improvement of the magnetic properties in all directions in the sheet surface. In addition, the lower limit of the content of C is not particularly limited, but considering the cost of decarburization treatment at the time of refining, it is preferable to be 0.0005% or more.

[0048] <<Si: 1.50% to 4.00%>>

[0049] Si increases the resistance, reduces the eddy current loss, decreases the iron loss, increases the yield ratio, and improves the punching processability of the iron core. When the Si content is less than 1.50%, these effects cannot be fully obtained. 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, the punching processability decreases due to excessive hardness increase, and cold rolling becomes difficult. Therefore, the Si content is set to 4.00% or less.

[0050] <<sol.Al: 0.0001% - 1.0%>>

[0051] sol.Al increases the resistance, reduces the eddy current loss, and decreases the iron loss. sol.Al also helps to increase the relative magnitude of the magnetic flux density B50 with respect to the saturation magnetic flux density. Here, the 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 fully obtained. 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 and the punching processability decreases. Therefore. The sol.Al content is set to 1.0% or less.

[0052] <<S: 0.0100% or less>>

[0053] S is not an essential element and is contained as an impurity in steel, for example. S hinders recrystallization and grain growth during annealing due to the precipitation of fine MnS. Therefore, the lower the S content, the more preferable. 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 considering the cost of desulfurization treatment during refining, it is preferably set to 0.0003% or more.

[0054] <<N: 0.0100% or less>>

[0055] Similar to C, N deteriorates the magnetic properties, so the lower the N content, the more preferable. 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 considering the cost of denitrification treatment during refining, it is preferably set to 0.0010% or more.

[0056] <<One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total of 2.50% - 5.00%>>

[0057] These elements are necessary elements for generating the α-γ phase transition, and therefore these elements need to be contained in total of 2.50% or more. On the other hand, if the total exceeds 5.00%, the cost is high, and sometimes the magnetic flux density decreases. Therefore, the total of these elements is 5.00% or less.

[0058] In addition, as a condition capable of generating the α-γ phase transition, the following condition is further satisfied. That is, when the Mn content is [Mn] in mass%, the Ni content is [Ni] in mass%, the Co content is [Co] in mass%, the Pt content is [Pt] in mass%, the Pb content is [Pb] in mass%, the Cu content is [Cu] in mass%, the Au content is [Au] in mass%, the Si content is [Si] in mass%, and the sol. Al content is [sol. Al] in mass%, it is preferable to satisfy the following formula (1) in mass%.

[0059] ([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au]) - ([Si] + [sol. Al]) > 0%... (1)

[0060] In the case where the above formula (1) is not satisfied, the α-γ phase transition does not occur, and therefore the magnetic flux density decreases.

[0061] <<Sn: 0.000% to 0.400%, Sb: 0.000% to 0.400%, P: 0.000% to 0.400%>>

[0062] Sn or Sb improves the magnetic flux density by improving the texture after cold rolling and recrystallization. Therefore, these elements can be contained as necessary, but if they are contained in excess, the steel becomes brittle. Therefore, the Sn content and the Sb content are each set to 0.400% or less. In addition, P can be contained in order to secure the hardness of the steel sheet after recrystallization, but if it is contained in excess, the steel becomes brittle. Therefore, the P content is set to 0.400% or less. In the case where the above further effects such as magnetic properties are imparted, it is preferable to contain one or more selected from the group consisting of Sn of 0.020% to 0.400%, Sb of 0.020% to 0.400%, and P of 0.020% to 0.400%.

[0063] <<One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: total of 0.0000% to 0.0100%>>

[0064] Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd react with S in molten steel at the time of casting of the molten steel to generate precipitates of sulfides or oxysulfides or both. Hereinafter, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd are sometimes collectively referred to as "coarse precipitate generating elements". The particle diameter of the precipitates of the coarse precipitate generating elements is about 1 to 2 μm, which is much larger than the particle diameter (about 100 nm) of fine precipitates such as MnS, TiN, and AlN. Therefore, these fine precipitates adhere to the precipitates of the coarse precipitate generating elements, and it is difficult to hinder recrystallization and grain growth during intermediate annealing. In order to sufficiently obtain these effects, the total of these elements is preferably 0.0005% or more. However, if the total of these elements exceeds 0.0100%, the total amount of sulfides or oxysulfides or both is excessive, and recrystallization and grain growth during intermediate annealing are hindered. Therefore, the total content of the coarse precipitate generating elements is 0.0100% or less.

[0065] <<Texture>>

[0066] Next, the texture of the non-oriented electromagnetic steel sheet of the present embodiment will be described. The manufacturing method will be described in detail later, but the non-oriented electromagnetic steel sheet of the present embodiment is of a chemical composition capable of generating α-γ phase transformation, and the microstructure is refined by quenching after finish rolling in hot rolling, thereby becoming a {100} grain growth microstructure. Thus, the aggregation strength of the {100} <011> orientation of the non-oriented electromagnetic steel sheet of the present embodiment becomes 5 to 30, and the magnetic flux density B50 in the direction at 45° to the rolling direction is particularly high. As such, the magnetic flux density is increased in a specific direction, but a high magnetic flux density is obtained on average in all directions as a whole. If the aggregation strength of the {100} <011> orientation is less than 5, the aggregation strength of the {111} <112> orientation, which decreases the magnetic flux density, is increased, and the magnetic flux density is decreased as a whole. In addition, the manufacturing method in which the aggregation strength of the {100} <011> orientation exceeds 30 requires thickening of the hot-rolled sheet, and there is a problem that manufacturing is difficult.

[0067] The aggregation strength of the {100} <011> orientation can be measured by an X-ray diffraction method or an electron backscatter diffraction (EBSD) method. Since the reflection angle of the sample from X-rays and electron beams differs in each crystal direction, the crystal orientation strength can be obtained from the reflection strength or the like, with the sample in a random direction as a reference. The aggregation strength of the {100} <011> orientation of the preferred non-oriented electromagnetic steel sheet of the present embodiment is 5 to 30 in terms of X-ray random intensity ratio. At this time, a value obtained by measuring the crystal orientation by EBSD and converted to the X-ray random intensity ratio can also be used.

[0068] <<Thickness>>

[0069] Next, the thickness of the non-oriented electromagnetic steel sheet of the present embodiment will be described. The thickness of the non-oriented electromagnetic steel sheet of the present embodiment is 0.50 mm or less. If 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.

[0070] <<Magnetic properties>>

[0071] Next, the magnetic properties of the non-oriented electromagnetic steel sheet of the present embodiment will be described. In investigating the magnetic properties, the values of B50, which is the magnetic flux density of the non-oriented electromagnetic steel sheet of the present embodiment, were 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 rolling direction refers to both sides. When the value of B50 in the rolling direction is denoted as B50L, the value of B50 in the direction inclined by 45° from the rolling direction is denoted as B50D1, the value of B50 in the direction inclined by 90° from the rolling direction is denoted as B50C, and the value of B50 in the direction inclined by 135° from the rolling direction is denoted as B50D2, the anisotropy of the magnetic flux density can be observed, in which B50D1 and B50D2 are the highest, and B50L and B50C are the lowest.

[0072] Here, for example, considering the case where the omnidirectional (0° to 360°) distribution of the magnetic flux density with the clockwise (or counterclockwise) direction as the positive direction, if the rolling direction is set to 0° (one side) and 180° (the other side), B50D1 is the B50 value at 45° and 225°, and B50D2 is the B50 value at 135° and 315°. Similarly, B50L is the B50 value at 0° and 180°, and B50C is the B50 value at 90° and 270°. The B50 value at 45° is strictly identical to the B50 value at 225°, and the B50 value at 135° is strictly identical to the B50 value at 315°. However, B50D1 and B50D2 are not strictly identical because there are cases where the magnetic properties are not easily made the same in actual manufacturing. Similarly, the B50 value at 0° is strictly identical to the B50 value at 180°, and the B50 value at 90° is strictly identical to the B50 value at 270°. On the other hand, there are cases where B50L and B50C are not strictly identical. In the non-oriented electromagnetic steel sheet of the present embodiment, the average of B50D1 and B50D2, and the average of B50L and B50C are used, and the following formulas (2) and (3) are satisfied.

[0073] (B50D1+B50D2) / 2>1.7T···(2)

[0074] (B50D1+B50D2) / 2>(B50L+B50C) / 2···(3)

[0075] In this way, if the magnetic flux density is measured, the average of B50D1 and B50D2 is 1.7 T or more as shown in Equation (2), and a high anisotropy of the magnetic flux density is confirmed as shown in Equation (3).

[0076] Further, in addition to satisfying Equation (1), it is preferable that the anisotropy of the magnetic flux density be higher than that of Equation (3) as shown in the following Equation (4).

[0077] (B50D1 + B50D2) / 2 > 1.1 x (B50L + B50C) / 2... (4)

[0078] Further, it is preferable that the anisotropy of the magnetic flux density be higher as shown in the following Equation (5).

[0079] (B50D1 + B50D2) / 2 > 1.2 x (B50L + B50C) / 2... (5)

[0080] Further, it is preferable that the average of B50D1 and B50D2 be 1.8 T or more as shown in the following Equation (6).

[0081] (B50D1 + B50D2) / 2 > 1.8 T... (6)

[0082] Further, the 45° is a theoretical value, and since there are cases where it does not easily coincide with 45° at the time of actual production, it also includes cases where it does not strictly coincide with 45°. The same applies to the 0°, 90°, 135°, 180°, 225°, 270°, and 315°.

[0083] The measurement of the magnetic flux density can be performed using a single sheet magnetic measuring device from a 55 mm square sample cut at 45°, 0°, and the like from the rolling direction.

[0084] <<Manufacturing Method>>

[0085] Next, one example of the manufacturing method of the non-oriented electromagnetic steel sheet of the present embodiment will be described. In 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), and the like are performed.

[0086] First, the steel material is heated and hot-rolled. The steel material is, for example, a billet manufactured by general continuous casting. The rough rolling and the finish rolling of the hot-rolling are performed at a temperature in the γ region (above the Ar1 temperature). That is, the hot-rolling is performed in such a manner that the final temperature of the finish rolling is above the Ar1 temperature and the coiling temperature is above 250°C and below 600°C. Thereby, by the subsequent cooling, the austenite phase changes to the ferrite phase, and the crystal structure is refined. When the cold-rolling is performed in the refined state thereafter, since the protruding recrystallization (hereinafter referred to as bulging) is easily generated, the {100} grains, which are normally difficult to grow, can be more easily grown.

[0087] Further, in 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 the phase change of the austenite to the ferrite. By refining the crystal structure like this, the bulging can be easily generated through the subsequent cold-rolling and intermediate annealing.

[0088] Thereafter, without performing the hot-rolled sheet annealing, the hot-rolled steel sheet is subjected to coiling and pickling. In the cold-rolling, the reduction rate is preferably set to be 80% to 95%. When the reduction rate is less than 80%, it is difficult to generate the bulging. When the reduction rate exceeds 95%, the {100} grains are easily grown by the subsequent bulging, but the hot-rolled steel sheet must be made thick, the coiling of the hot-rolling becomes difficult, and the operation becomes difficult. The reduction rate of the cold-rolling is more preferably 86% or more. When the reduction rate of the cold-rolling is 86% or more, the bulging is more easily generated.

[0089] After the cold-rolling is completed, the intermediate annealing is performed. In manufacturing the non-oriented electromagnetic steel sheet of the present embodiment, the intermediate annealing is performed at a temperature at which the austenite phase does not change. That is, the temperature of the intermediate annealing is preferably set to be less than the Ac1 temperature. By performing the intermediate annealing like this, the bulging is generated, and the {100} grains are easily grown. Further, the time of the intermediate annealing is preferably set to be 5 seconds to 60 seconds.

[0090] After the intermediate annealing, skin pass rolling is performed. When the skin pass rolling and annealing are performed in the state where the expansion is generated as described above, the {100} grains grow further from the portion where the expansion is generated. This is because, by the skin pass rolling, the {100} <011> grains have a property that they are difficult to accumulate strain and the {111} <112> grains are easy to accumulate strain, and in the subsequent annealing, the {100} <011> grains, which have less strain, eat away the {111} <112> grains as a driving force of the difference in strain. This eating away phenomenon generated as a driving force of the difference in strain is called strain-induced boundary migration (hereinafter referred to as SIBM). The reduction in the skin pass rolling is preferably set to 5% to 25%. When the reduction is less than 5%, the amount of strain is too small, and thus it is difficult to cause SIBM in the subsequent annealing, and the {100} <011> grains do not grow. On the other hand, when the reduction exceeds 25%, the amount of strain is too large, and recrystallization nucleation (hereinafter referred to as nucleation) in which new grains are generated from the {111} <112> grains occurs. In this nucleation, since most of the generated grains are {111} <112> grains, the magnetic properties deteriorate.

[0091] After the skin pass rolling is performed, final annealing is performed in order to release the strain and improve workability. The final annealing is also set to a temperature at which the austenite phase does not change, and the temperature of the final annealing is set to be lower than the Ac1 temperature. By performing the final annealing like this, the {100} <011> grains eat away the {111} <112> grains, and it is possible to improve the magnetic properties. In addition, the time at which the temperature becomes 600°C to the Ac1 temperature is set to be within 1200 seconds in the final annealing. If the annealing time is too short, almost all of the strain imparted in the skin pass rolling remains, and warping occurs when a complicated shape is punched out. On the other hand, if the annealing time is too long, the grains become too coarse, the burr becomes large at the time of punching, and it is not possible to obtain the punching accuracy.

[0092] After the final annealing is completed, forming processing of the non-oriented electromagnetic steel sheet and the like is performed in order to produce the desired steel member. Furthermore, in order to remove the strain and the like generated in the steel member composed of the non-oriented electromagnetic steel sheet due to the forming processing and the like (for example, punching), stress relief annealing is performed on the steel member. In the present embodiment, since the SIBM is generated and the crystal grain diameter is made coarse at a temperature below the Ac1 temperature, the temperature of the stress relief annealing is set to be around 800°C, for example, and the time of the stress relief annealing is set to be around 2 hours. By the stress relief annealing, it is possible to improve the magnetic properties.

[0093] In the non-oriented electromagnetic steel sheet (steel member) of the present embodiment, in the manufacturing method described above, finish rolling is performed at a temperature of Ar1 or higher mainly in the hot rolling step, and thus a higher B50 of the above-described equation (1) and excellent anisotropy of the above-described equation (2) are obtained. Furthermore, by setting the reduction to around 10% in the skin pass rolling step, more excellent anisotropy of the above-described equation (4) is obtained.

[0094] Further, in the present embodiment, the Ar1 temperature is found from thermal expansion changes of the steel material (steel sheet) during cooling at an average cooling rate of 1°C / sec. In addition, in the present embodiment, the Ac1 temperature is found from thermal expansion changes of the steel material (steel sheet) during heating at an average heating rate of 1°C / sec.

[0095] A steel member composed of the non-oriented electromagnetic steel sheet of the present embodiment can be manufactured as above.

[0096] Next, with respect to the non-oriented electromagnetic steel sheet of the present embodiment, examples are shown and specifically described. The examples shown below are merely one example of the non-oriented electromagnetic steel sheet, and the non-oriented electromagnetic steel sheet is not limited to the examples below.

[0097] [Example 1]

[0098] By casting molten steel, ingots having the compositions shown in Tables 1 to 2 below were produced. Here, the left side indicates the value of the left side of the above-described formula (1). Subsequently, the produced ingots were heated to 1150°C and hot-rolled to be rolled in a manner such that the sheet thickness becomes 2.5 mm. Then, after the finish rolling, water cooling was performed, and the hot-rolled steel sheet was coiled. The temperature at the stage of the final pass of the finish rolling (final temperature) at this time was 830°C, and all were temperatures greater than the Ar1 temperature. Further, with respect to No. 108 in which the γ-α phase transformation does not occur, the final temperature was set to 850°C. In addition, with respect to the coiling temperature, the conditions shown in Table 1 were performed.

[0099] Next, the oxide layer was removed from the hot-rolled steel sheet by pickling, and rolling was performed at the reduction rates after cold-rolling shown in Table 1. Then, intermediate annealing was performed at 700°C for 30 seconds in an oxidation-free atmosphere. Next, rolling was performed at the reduction rates of the second cold-rolling (skin pass rolling) shown in Table 1.

[0100] Next, in order to investigate the magnetic properties, final annealing was performed at 800°C for 30 seconds after the second cold-rolling (skin pass rolling), and after the sample was produced by shearing processing to be 55 mm square, stress relief annealing was performed at 800°C for 2 hours, and the magnetic flux density B50 was measured. The sample was collected from two directions of 0° and 45° with respect to the rolling direction to be 55 mm square. Then, the two samples were measured, and the magnetic flux densities B50 with respect to the rolling direction of 0°, 45°, 90°, and 135° were respectively denoted as B50L, B50D1, B50C, and B50D2.

[0101] [Table 1]

[0102]

[0103] [Table 2]

[0104]

[0105] The underlines in Tables 1 to 2 indicate conditions deviating from the scope of the present application. No. 101 to No. 107, No. 109 to No. 111, No. 114 to No. 130 as inventive examples all have good values of magnetic flux density B50 in the 45° direction and the full-width average. However, No. 116 and No. 127 have slightly low magnetic flux density B50 because of deviating from the proper coiling temperature. No. 129 and No. 130 have slightly low magnetic flux density B50 because of the low cold-rolling reduction ratio, compared with No. 118 as an equivalent composition and coiling temperature. On the other hand, No. 108 as a comparative example has a high Si concentration, and the value on the left side of the formula is 0 or less, which is a composition not undergoing α-γ phase transformation, and thus has low magnetic flux density B50. No. 112 as a comparative example has low {100} <011> strength of less than 5 because of the low skin finish ratio, and thus has low magnetic flux density B50. No. 113 as a comparative example has {100} <011> strength of 30 or more, and deviates from the present application. No. 113 also has a hot-rolled plate thickness of 7 mm, and thus has the difficulty of being hard to handle.

[0106] <<2nd Embodiment>>

[0107] A cast ingot having the composition shown in Table 3 below was produced by casting molten steel. Thereafter, the produced cast ingot was heated to 1150°C and hot-rolled to a sheet thickness of 2.5 mm. Then, after finishing rolling, the hot-rolled steel sheet was water-cooled and coiled. The final temperature in the stage of the final pass of the finishing rolling at this time was 830°C, which was a temperature greater than the Ar1 temperature.

[0108] Next, the oxide layer was removed from the hot-rolled steel sheet by pickling, and cold-rolled until the sheet thickness became 0.385 mm. Then, intermediate annealing was performed in an oxidation-free atmosphere, and the temperature of the intermediate annealing was controlled so that the recrystallization rate became 85%. Next, second cold-rolling (skin pass rolling) was performed until the sheet thickness became 0.35 mm.

[0109] Next, in order to investigate the magnetic properties, final annealing was performed at 800°C for 30 seconds after the second cold-rolling (skin pass rolling), and a 55 mm square sample was produced by shearing processing, and stress relief annealing was performed at 800°C for 2 hours, and the magnetic flux density B50 and the iron loss W10 / 400 were measured. The magnetic flux density B50 was measured in the same order as in the first embodiment. On the other hand, the iron loss W10 / 400 was measured as the energy loss (W / kg) generated in the sample when an alternating magnetic field of 400 Hz was applied in such a manner that the maximum magnetic flux density became 1.0 T. The iron loss was the average of the results measured at 0°, 45°, 90°, 135° with respect to the rolling direction.

[0110] [Table 3]

[0111]

[0112] [Table 4]

[0113]

[0114] All of No. 201 to No. 214 are inventive examples, and the magnetic properties are all good. In particular, the magnetic flux density B50 of No. 202 to No. 204 is higher than that of No. 201, No. 205 to No. 214, and the iron loss W10 / 400 of No. 205 to No. 214 is lower than that of No. 201 to No. 204.

[0115] Further, in the following description, the direction inclined by 45° from the rolling direction described in the description of the example of the electromagnetic steel sheet used in the divided core will be referred to as the angle of 45° from the rolling direction as necessary, and the direction inclined by 135° from the rolling direction will be referred to as the angle of 135° from the rolling direction as necessary. Further, the direction inclined by θ° from the rolling direction will be referred to as the direction of the angle of θ° from the rolling direction as necessary. As such, the direction inclined by θ° from the rolling direction and the direction of the angle of θ° from the rolling direction mean the same thing.

[0116] The above non-oriented electromagnetic steel sheet is a steel sheet newly developed by the present inventors, and the magnetic properties are best in the two directions of the angle of 45° and 135° from the rolling direction. On the other hand, the magnetic properties are worst in the two directions of the angle of 0° and 90° from the rolling direction. Here, the 45° and 135° are theoretical values, and there are cases where the 45° and 135° do not easily coincide in actual manufacturing. Therefore, if the two directions of the angle of 45° and 135° from the rolling direction are theoretically the directions in which the magnetic properties are best, the 45° and 135° also include cases where the 45° and 135° do not strictly coincide in the actual non-oriented electromagnetic steel sheet. The same is true in the 0° and 90°. In addition, the magnetic properties of the two directions in which the magnetic properties are best are theoretically the same, but there are cases where the magnetic properties of the two directions do not easily become the same in actual manufacturing. Therefore, if the magnetic properties of the two directions in which the magnetic properties are best are theoretically the same, the same also includes cases where the magnetic properties are not strictly the same. The same is true in the two directions in which the magnetic properties are worst. Further, the angle of the clockwise angle is set to a positive angle.

[0117] <Stator Core>

[0118] The present inventors have researched a stator core composed of a plurality of divided cores in a manner that can effectively utilize the characteristics of the above-described non-oriented electromagnetic steel sheet, and have found the embodiments described below.

[0119] An embodiment of the present application will be described below with reference to the drawings. In the following description, the electromagnetic steel sheet is the non-oriented electromagnetic steel sheet described in the item of "Example of electromagnetic steel sheet used in divided core" unless specifically described. In addition, in the following description, the same (identical) in length, direction, position, and the like includes the same (identical) except for (strictly) the same (identical) within a range not departing from the gist of the application (for example, within a range of errors generated in a manufacturing process).

[0120] Further, in the present embodiment, an electric motor is exemplified as the rotary electric machine, specifically, an alternating-current electric motor is exemplified, more specifically, a synchronous electric motor is exemplified, and further specifically, a permanent magnet field type electric motor is exemplified as one example. Such an electric motor is suitable for use in an electric automobile or the like, for example.

[0121] Figure 1 is a view showing one example of the configuration of the rotary electric machine 10. Figure 1 is a view (plan view) of the rotary electric machine 10 as viewed from a direction parallel to the axis of the rotary electric machine. Figure 1 The relationship of the directions in the X-Y-Z coordinate system shown in the drawing.

[0122] As shown in Figure 1 , the rotary electric machine 10 includes a stator 20 and a rotor 50. The stator 20 and the rotor 50 are housed in a housing not shown. In addition, the stator 20 is fixed to the housing.

[0123] In the present embodiment, as the rotary electric machine 10, an inner rotor type in which the rotor 50 is located on the inner side of the stator 20 is adopted. However, as the rotary electric machine 10, an outer rotor type in which the rotor 50 is located on the outer side of the stator 20 can also be adopted. In addition, in the present embodiment, the rotary electric machine 10 is a 10-pole 12-slot three-phase alternating-current electric motor. However, the number of poles, the number of slots, the number of phases, and the like can be appropriately changed.

[0124] The stator 20 includes a stator core 21 and a coil not shown.

[0125] In the following description, the axial direction of the stator core 21 (the direction along the center axis O of the stator core 21 (Z-axis direction)) will be referred to as the axial direction as needed. In addition, the radial direction of the stator core 21 (the direction orthogonal to the center axis O of the stator core 21) will be referred to as the radial direction as needed. In addition, the circumferential direction of the stator core 21 (the direction encircling the center axis O of the stator core 21) will be referred to as the circumferential direction as needed.

[0126] The stator core 21 has a plurality of divided cores 30. Specifically, the stator core 21 of the present embodiment has 12 divided cores 30 arranged in the circumferential direction, that is, the direction around the center axis O. The divided cores 30 of the present embodiment are each the same shape and the same size. Each divided core 30 has a tooth portion 31 and a core back portion 32.

[0127] The tooth portion 31 has the winding of the stator 20 wound therearound. The tooth portion 31 protrudes toward the radially inner side from the core back portion 32. That is, the tooth portion 31 protrudes toward the center axis O in the radial direction. The tooth portions 31 are arranged at equal intervals in the circumferential direction. In the present embodiment, 12 tooth portions 31 are provided at intervals of 30° about the center axis O of the stator core 21. Further, the winding of the stator 20 can be concentratedly wound or distributedly wound.

[0128] The core back portion 32 is formed in a circular arc shape. The plurality of divided cores 30 are arranged in the circumferential direction, and thus the core back portion 32 is formed as a whole in a circular ring shape.

[0129] Figure 2 is a view showing one example of the configuration of the divided core 30. Figure 2 is a view (perspective view) of one of the plurality of divided cores 30 provided in the stator core 21, as viewed obliquely.

[0130] The divided core 30 is configured by laminating core pieces 40 made of an electromagnetic steel sheet. Each core piece 40 is a plate shape, and is the same shape and the same size. The core pieces 40 are laminated in the same orientation in the plate thickness direction, and thus the divided core 30 is the same shape in the axial direction, that is, the center axis O.

[0131] Figure 3 is a view showing one example of the configuration of the core piece 40. Figure 3 is a plan view of one of the plurality of core pieces 40 configuring the divided core 30, as viewed along the center axis O. As shown in Figure 3 , the core piece 40 has a tooth 41 and a core back 42.

[0132] The tooth 41 configures the tooth portion 31 of the divided core 30 by being laminated by the core pieces 40. Further, the tooth 41 has a tooth base portion 41a extending in the radial direction from the circumferential center of the core back 42 and a flange portion 41b located at the front end of the tooth base portion 41a. In the case where the divided core 30 is used to configure the rotary electric machine 10, the flange portion 41b opposes the rotor 50.

[0133] The core back 42 is formed by stacking core chips 40 to form the core back 32 of the segmented core 30. The core back 42 has a circumferentially protruding convex portion 43a at one end and a circumferentially recessed portion 43b at the other end. The convex portion 43a and the recessed portion 43b are inverted shapes. When multiple segmented cores 30 are arranged circumferentially, the convex portion 43a engages with the recessed portion 43b of the adjacent core chip 40, and the recessed portion 43b engages with the convex portion 43a of the adjacent core chip 40.

[0134] In the iron chip 40, the radial direction of the tooth 41 is orthogonal to the extending direction of the iron core back 42. For example... Figure 3 As shown by the single-dotted line L1, the radial direction of tooth 41 refers to the direction of a line parallel to the plate surface of tooth 41 and along the center of the circumference of tooth 41. Alternatively, the radial direction of tooth 41 refers to the direction of a line parallel to the plate surface of tooth 41 and along the line connecting the position P that bisects the length of the outer perimeter of the iron core back 42 and the center of the circle of the outer perimeter of the iron core back 42.

[0135] On the other hand, the extending direction of the core back 42 refers to the direction orthogonal to the radial direction of the tooth 41. That is, as... Figure 3 As shown by the dashed line L2, the extension direction of the iron core back 42 refers to the direction along the tangent to the outer periphery of the iron core back 42 at position P where the dashed line L1 intersects with the outer periphery of the iron core back 42. Alternatively, the extension direction of the iron core back 42 refers to the direction along the tangent to the outer periphery of the iron core back 42 at position P that bisects the length of the outer periphery of the iron core back 42.

[0136] return Figure 1 The rotor 50 is arranged radially inside the stator 21. The rotor 50 includes a rotor core 51, a plurality of permanent magnets 52, and a rotating shaft 60.

[0137] The rotor core 51 is coaxially arranged with the stator core 21. The rotor core 51 is approximately annular (ring-shaped). Multiple permanent magnets 52 are fixed to the rotor core 51. In this embodiment, five groups (ten in total) of permanent magnets 52 are arranged at 36° intervals around the central axis O of the rotor core 51. A rotating shaft 60 is disposed within the rotor core 51. The rotating shaft 60 is fixed to the rotor core 51.

[0138] In this embodiment, a surface magnet type motor is used as the permanent magnet excitation type motor, but an embedded magnet type motor may also be used.

[0139] Here, the core piece 40 is formed, for example, by punching processing of an electromagnetic steel sheet that is a mother material (strip steel) in a plate shape by rolling. The electromagnetic steel sheet is the electromagnetic steel sheet described in the item of <Example of electromagnetic steel sheet used in divided core>. The ratios (B50 ratio, W15 / 50 ratio, W15 / 100 ratio) of the electromagnetic steel sheet described in the item of <Example of electromagnetic steel sheet used in divided core> to B50, W15 / 50, W15 / 100 of a known non-oriented electromagnetic steel sheet are shown in Table 5. The thickness of any of the electromagnetic steel sheets is 0.25 [mm]. As the known non-oriented electromagnetic steel sheet, a non-oriented electromagnetic steel sheet of W10 / 400 of 12.8 W / kg is used. W10 / 400 is the iron loss at a magnetic flux density of 1.0 T and a frequency of 400 Hz. In addition, the known non-oriented electromagnetic steel sheet is excellent only in the rolling direction magnetic characteristics. In the following description, the electromagnetic steel sheet described in the item of <Example of electromagnetic steel sheet used in divided core> is also referred to as a development material as needed. In addition, the known non-oriented electromagnetic steel sheet is also referred to as an existing material as needed.

[0140] [Table 5]

[0141] B50 ratio [-] W15 / 50 ratio [-] W15 / 100 ratio [-] Development material 1.051 0.880 0.865

[0142] Here, B50 is the magnetic flux density at the time of excitation at a magnetic field strength of 5000 [A / m], and W15 / 100 is the iron loss at a magnetic flux density of 1.5 [T] and a frequency of 100 [Hz]. Here, the magnetic flux density and the iron loss are measured by the method described in JIS C 2556:2015. In addition, in Table 5, the value obtained by normalizing the average value of each angle from the rolling direction of the development material to 1.000 of the average value of each angle from the rolling direction of the existing material (= average value of each angle from the rolling direction of the development material ÷ average value of each angle from the rolling direction of the existing material) is shown. Like this, the value of Table 5 is a relative value (dimensionless quantity).

[0143] According to Table 5, the B50 of the development material is 5.1 [%] larger than the B50 of the existing material. The W15 / 50 of the development material is 12.0 [%] smaller than the W15 / 50 of the existing material. The W15 / 100 of the development material is 13.5 [%] smaller than the W15 / 100 of the existing material. Like this, the development material is larger in B50 and smaller in iron loss than the existing material.

[0144] Figure 4 is a graph showing one example of the relationship between the B50 ratio and the angle from the rolling direction. Figure 5 is a graph showing one example of the relationship between the W15 / 50 ratio and the angle from the rolling direction. Figure 6This is an example graph showing the relationship between the W15 / 100 ratio and the angle relative to the rolling direction.

[0145] Figure 7 This is an example graph showing the relationship between the rolling direction RD and the direction with the best magnetic properties. In the following description, the direction with the best magnetic properties will be referred to as the easy magnetization direction as needed. Figure 7 In this context, when the counterclockwise angle is set to a positive value and the rolling direction RD is set to 0°, the easy magnetization directions are ED1 and ED2. The direction from the rolling direction RD to the smaller of the two angles (RD and ED1) is 90°. Figure 7 The magnetic properties of the four regions (indicated by the dashed lines) are theoretically symmetrical.

[0146] in addition, Figure 4 , Figure 5 , Figure 6 The B50 ratio, W15 / 50 ratio, and W15 / 100 ratio shown are the same as those in Table 5, and are values ​​obtained by standardizing the average value of each angle from the rolling direction of the existing material. That is, Figure 4 , Figure 5 , Figure 6 The values ​​of B50 ratio, W15 / 50 ratio, and W15 / 100 ratio shown are relative values ​​(dimensionless quantities).

[0147] like Figure 4 As shown, among the developed materials, the B50 ratio is the largest when the angle with the rolling direction is 45°, and the closer the angle with the rolling direction is to 0° or 90°, the smaller the B50 ratio becomes.

[0148] On the other hand, among existing materials, the B50 ratio is smallest when the angle with the rolling direction is 45°.

[0149] like Figure 5 and Figure 6 As shown, among the developed materials, the W15 / 50 ratio and W15 / 100 ratio are largest when the angle with the rolling direction is 45°. The closer the angle with the rolling direction is to 0° or 90°, the smaller the W15 / 50 ratio and W15 / 100 ratio become.

[0150] On the other hand, in existing materials, the W15 / 50 ratio and W15 / 100 ratio increase when the angle with the rolling direction is 45° to 90°.

[0151] Among the above such development materials, the magnetic properties are most excellent in the direction at an angle of 45° to the rolling direction (easy magnetization direction ED1) and the direction at an angle of 135° to the rolling direction (easy magnetization direction ED2). On the other hand, the magnetic properties are worst in the direction at an angle of 0° to the rolling direction (rolling direction RD) and the direction at an angle of 90° to the rolling direction (direction orthogonal to the rolling direction RD).

[0152] The inventors have conceived that a core piece is produced from a development material whose magnetic properties are more excellent than those of the conventional material, and a stator core having a divided core made by laminating the produced core pieces is manufactured, whereby the magnetic properties of the entire stator core can be improved. In addition, the directions in which the magnetic properties of the development material are excellent are the directions at an angle of 45° and 135° to the rolling direction, and the directions in which the magnetic properties are excellent are orthogonal to each other. On the other hand, the radial direction of the teeth of the core piece and the extending direction of the core back are also orthogonal to each other. Therefore, the inventors have conceived that the directions in which the magnetic properties of the development material are excellent can be made to coincide with the radial direction of the teeth and the extending direction of the core back to produce the core piece.

[0153] Based on such a concept, the core piece is configured so that the radial direction of the teeth is along the direction at an angle of 45° to the rolling direction of the development material, while the extending direction of the core back is along the direction at an angle of 135° to the rolling direction of the development material. Alternatively, the core piece is configured so that the radial direction of the teeth is along the direction at an angle of 135° to the rolling direction of the development material, while the extending direction of the core back is along the direction at an angle of 45° to the rolling direction of the development material.

[0154] <Method of manufacturing stator core>

[0155] Next, a method of manufacturing the stator core 21 including a process of producing the core piece 40 from the development material will be described. The stator core 21 is manufactured mainly through a core piece production process, a divided core production process, and a stator core production process.

[0156] [Core piece production process]

[0157] In the core piece production process, the core piece 40 is produced by punching the development material using a die.

[0158] Figure 8 is a view for explaining the die for punching the development material. Figure 8 is a schematic view (plan view) as viewed from the direction orthogonal to the plate surface of the development material 80. In addition, in Figure 8 , the rolling direction RD and the directions in which the magnetic properties are excellent (ED1, ED2) are indicated in correspondence with the development material 80.

[0159] The development material 80 is in a strip shape with the rolling direction RD as the longitudinal direction. The development material 80 is conveyed in the longitudinal direction by a conveying device. Therefore, in Figure 8In the example shown, the rolling direction RD is the same as the direction of conveyance by the conveyance device. At both ends in the width direction of the development material 80, pilot holes 81 are provided at intervals in the length direction.

[0160] First, the conveyance device inserts the pilot into the pilot hole 81 and conveys the development material 80 by a certain distance. Next, the punching device generates the core piece 40 by blanking the conveyed development material 80 using a die having a punch and a die. Here, a plurality of core pieces 40 of the same shape and the same size are respectively generated by one blanking by the punching device.

[0161] The punching device blanks the development material 80 in such a manner that either the radial direction of the teeth of the core piece 40 or the extension direction of the core back becomes a direction in which the magnetic characteristics of the development material 80 are excellent. As shown in Figure 8 Specifically, the die of the punching device is set such that the radial direction of the teeth of the core piece 40 (single-dot chain line L1) is along a direction in which the angle with the rolling direction of the development material 80 is 45° (along the easy magnetization direction ED1). Further, since the radial direction of the teeth of the core piece 40 is orthogonal to the extension direction of the core back, the radial direction of the teeth is along a direction in which the angle with the rolling direction of the development material 80 is 45°, and thus the extension direction of the core back is set to be along a direction in which the angle with the rolling direction of the development material 80 is 135° (along the easy magnetization direction ED2).

[0162] Therefore, the radial direction of the teeth of the core piece 40 blanked by the punching device is along a direction in which the angle with the rolling direction is 45°, and the extension direction of the core back is along a direction in which the angle with the rolling direction is 135°. Further, in the present embodiment, all of the core pieces 40 blanked by the punching device are in the same orientation. Therefore, for all of the core pieces 40 blanked, the radial direction of the teeth is along a direction in which the angle with the rolling direction is 45°, and the extension direction of the core back is along a direction in which the angle with the rolling direction is 135°.

[0163] Further, in Figure 8 , the die that blanks the core piece 40 in such a manner that the radial direction of the teeth is along a direction in which the angle with the rolling direction is 45°, and the extension direction of the core back is along a direction in which the angle with the rolling direction is 135° is described, but is not limited to this case.

[0164] For example, as shown in Figure 8The iron core pieces 40A, 40B shown by the alternate long and short dash line can also be punched by a die in which the radial direction of the teeth is in a direction in which the angle with the rolling direction is 135° and the extension direction of the core back is in a direction in which the angle with the rolling direction is 45°. In this case, the radial direction of the teeth of the punched iron core pieces 40A, 40B is in a direction in which the angle with the rolling direction is 135° and the extension direction of the core back is in a direction in which the angle with the rolling direction is 45°.

[0165] In addition, as Figure 8 The iron core piece 40C shown by the alternate long and short dash line can also be punched by a die in which the radial direction of the teeth is in a direction in which the angle with the rolling direction is 135° and the extension direction of the core back is in a direction in which the angle with the rolling direction is 45°. Figure 8 The iron core piece 40C shown by the alternate long and short dash line can also be punched by a die in which the radial direction of the teeth is in a direction in which the angle with the rolling direction is 135° and the extension direction of the core back is in a direction in which the angle with the rolling direction is 45°. Figure 8 The iron core piece 40C shown by the alternate long and short dash line can also be punched by a die in which the radial direction of the teeth is in a direction in which the angle with the rolling direction is 135° and the extension direction of the core back is in a direction in which the angle with the rolling direction is 45°.

[0166] In addition, in the Figure 8 In addition, in the Figure 8 In addition, in the

[0167] [Divided Core Generation Process]

[0168] In the divided core generation process, the iron core pieces 40 are stacked to generate the divided core 30.

[0169] Specifically, after the plurality of iron core pieces 40 punched out by the punching device in the iron core piece generation process are aligned in a manner in which all of the iron core pieces 40 become the same orientation, the iron core pieces 40 are connected and stacked in a manner in which the board surfaces of the iron core pieces 40 abut each other. In order to connect the plurality of iron core pieces 40, the iron core pieces 40 can be connected by bonding the board surfaces of the iron core pieces 40 to each other using an adhesive or by riveting or welding the iron core pieces 40 in the length direction. Furthermore, the number of the iron core pieces 40 stacked is changed according to the specifications or size of the stator core 21 manufactured. In addition, in the case of manufacturing the stator core 21 of the present embodiment, 12 divided cores 30 are generated on one stator core 21.

[0170] Here, as described above, either of the radial direction of the teeth of the core piece 40 and the extending direction of the core back is a direction in which the magnetic properties of the development material 80 are excellent, and the divided core 30 is aligned and stacked in a manner in which all of the core pieces 40 are in the same orientation. Therefore, the divided core 30 in which the core pieces 40 are stacked can improve the magnetic properties of the tooth portions 31 and the core back portions 32.

[0171] [Stator Core Generation Process]

[0172] In the stator core generation process, the divided cores 30 are arranged and connected in the circumferential direction to generate the stator core 21. Specifically, the core back portions 32 of the plurality of divided cores 30 generated in the divided core generation process are arranged in a manner in which they are circular ring-shaped. At this time, the adjacent divided cores 30 are positioned to each other by the fitting of the convex portions 43a and the concave portions 43b of the respective core pieces 40. In order to connect the divided cores 30, the core back portions 32 of the adjacent divided cores 30 can be connected to each other by adhesion using an adhesive or welding.

[0173] In addition, in the case of manufacturing the stator core 21 of the present embodiment, 12 divided cores 30 are arranged and connected in the circumferential direction.

[0174] The stator core 21 can be manufactured by the above-described process. Furthermore, in the case of manufacturing the stator 20 or the rotary electric machine 10 using the manufactured stator core 21, a publicly known manufacturing method can be used.

[0175] [Example]

[0176] Next, the magnetic properties between the divided core using the core piece generated from the development material and the divided core using the core piece generated from the existing material are compared.

[0177] First, a sample of the divided core is generated by stacking the core pieces generated by blanking the development material. The divided core using the core piece of the development material like this is referred to as the divided core of the inventive example. In addition, the core piece obtained by blanking the development material is referred to as the core piece of the inventive example. The divided core of the inventive example is generated by the method described in the item of the above-described <Manufacturing Method of Stator Core>. Furthermore, the radial direction of the teeth of the core piece of the inventive example is along a direction in which the angle with the rolling direction of the development material is 45°, and the extending direction of the core back is along a direction in which the angle with the rolling direction of the development material is 135°.

[0178] On the other hand, the core pieces generated by punching the existing material were laminated to generate a divided core of the test sample. The divided core of the core pieces using the existing material like this is referred to as a divided core of the comparative example. In addition, the core pieces generated by punching the conventional material are referred to as core pieces of the comparative example. The divided core of the comparative example is generated by the method described in the above-mentioned item of "Manufacturing method of stator core". Furthermore, the teeth of the core pieces of the comparative example have a radial direction along a direction in which the angle with the rolling direction of the conventional material is 0°, and the extension direction of the core back is along a direction in which the angle with the rolling direction of the conventional material is 90°.

[0179] In addition, the divided core of the inventive example and the divided core of the comparative example are the following specifications.

[0180] Outer diameter of stator core: 77.0 [mm], inner diameter of stator core: 40.0 [mm], height (laminated thickness) of stator core: 45.0 [mm], thickness of core piece (electromagnetic steel sheet): 0.25 [mm], number of poles: 10, number of slots: 12

[0181] Here, as a comparison of the magnetic properties between the divided core of the inventive example and the divided core of the comparative example, the ratio of the magnetic flux density when excited at B50, that is, the strength of the magnetic field of 5000 [A / m] is shown in Table 6.

[0182] [Table 6]

[0183] B50 ratio [-] Split core of the inventive example 1.042 Split core of the comparative example 1.000

[0184] As shown in Table 6, in a case where the magnetic flux density of the divided core of the comparative example is set to 1.000, the magnetic flux density of the divided core of the inventive example is 1.042. According to Table 6, B50 of the divided core of the inventive example is 4.2 [%] larger than B50 of the divided core of the comparative example. As such, it can be confirmed that the divided core using the core pieces generated from the development material has a larger magnetic flux density and improved magnetic properties compared to the divided core using the core pieces generated from the existing material.

[0185] As such, by arranging the divided core of the inventive example having a large magnetic flux density in the circumferential direction to manufacture a stator core (referred to as a stator core of the inventive example), the magnetic flux density can be increased in the entire stator core compared to the stator core manufactured by arranging the divided core of the inventive example in the circumferential direction (referred to as a stator core of the comparative example), and the magnetic properties can be improved.

[0186] In addition, by applying the stator core of the present embodiment, which has a large magnetic flux density, to the rotating electric machine, the torque can be increased as compared with the rotating electric machine to which the stator core of the comparative example is applied. In addition, in the rotating electric machine to which the stator core of the present embodiment is applied, in a case where the same torque is output as in the rotating electric machine to which the stator core of the comparative example is applied, the current flowing in the winding wound around the stator core of the present embodiment can be reduced, and thus the copper loss can be reduced.

[0187] As described above, according to the present embodiment, by using the electromagnetic steel sheet of the development material having excellent magnetic properties in the core piece constituting the divided core, the magnetic properties of the entire stator core provided with the divided core can be improved. In addition, according to the present embodiment, for each core piece of all the divided cores provided in the stator core, either the radial direction of the tooth or the extension direction of the core back is in the direction in which the electromagnetic steel sheet of the development material has excellent magnetic properties, and thus the magnetic properties of the entire stator core can be further improved. Further, since the magnetic saturation of the stator core can be suppressed even if the width of the tooth portion and the width of the core back portion are narrowed by the improvement of the magnetic properties, the area of the slot can be enlarged, and the space factor of the winding can be improved.

[0188] Further, in the present embodiment, the superiority of the development material is described as compared with the case where the conventional material is the non-oriented electromagnetic steel sheet, and the development material also has superiority as compared with the case where the conventional material is the bi-directional electromagnetic steel sheet. Specifically, as compared with the case where the conventional material is the bi-directional electromagnetic steel sheet, the development material can reduce the manufacturing cost. In addition, as compared with the case where the conventional material is the bi-directional electromagnetic steel sheet, the grain size of the steel sheet structure of the development material is small, and thus the iron loss under a high frequency condition when the core pieces are laminated to constitute the divided core can be suppressed.

[0189] <Modification>

[0190] In the above-described present embodiment, for each core piece of all the divided cores provided in the stator core, the case where either the radial direction of the tooth or the extension direction of the core back is in the direction in which the electromagnetic steel sheet of the development material has excellent magnetic properties is described, but is not limited to this case.

[0191] In the present modification example, for each of the core pieces of at least one of the plurality of divided cores provided to the stator core, it is explained that either the radial direction of the tooth or the extending direction of the core back can be in a direction in which the magnetic characteristics of the electromagnetic steel sheet of the development material are excellent. In other words, the stator core of the present modification example has a mixed presence of a divided core composed of core pieces in which either the radial direction of the tooth or the extending direction of the core back is in a direction in which the magnetic characteristics of the electromagnetic steel sheet of the development material are excellent, and a divided core composed of core pieces in which neither the radial direction of the tooth nor the extending direction of the core back is in a direction in which the magnetic characteristics of the electromagnetic steel sheet of the development material are excellent. In the stator core in which such different kinds of divided cores are mixed, a portion in which the magnetic characteristics are good and a portion in which this is not the case are generated, a deviation occurs in the distribution of the magnetic characteristics of the stator core, and the iron loss becomes large.

[0192] In the present modification example, in the case where different kinds of divided cores are mixed, the stator core is configured in such a manner that the width of the tooth portion in the radial direction in which the magnetic characteristics are excellent is narrower than the width of the tooth portion in the radial direction in which the magnetic characteristics are not excellent. Furthermore, in the present modification example, in the case where different kinds of divided cores are mixed, the stator core is configured in such a manner that the product of the width of the tooth portion of the divided core and the magnetic flux density of the tooth portion when excitation is performed at a predetermined magnetic field strength is substantially constant for each tooth portion of all the divided cores. By configuring the stator core in this manner, even in the stator core in which different kinds of divided cores are mixed, it is possible to reduce the deviation of the magnetic flux density and suppress the iron loss.

[0193] Figure 9 is a drawing for explaining the width of the tooth portion. Figure 9 (a) of is one example of a tooth portion 31A in which the radial direction is parallel. In this example, the tooth portion 31A itself is parallel in the radial direction. Figure 9 (b) of is one example of a tooth portion 31B in which the slot is parallel in the radial direction. In this example, the slot between the tooth portions 31B adjacent in the circumferential direction is parallel in the radial direction.

[0194] Here, the width of the tooth portion refers to the length of the circumferential direction of the stator core at the position of the center of the tooth straight region. The tooth straight region refers to a region in which, in a cross section of the stator core when cut in a direction perpendicular to the axis of the stator core, the longest straight line among the straight lines constituting the end portions of the tooth portion in the circumferential direction of the stator core is obtained for each of the two end portions of the tooth portion in the circumferential direction of the stator core.

[0195] In Figure 9 In the example shown in (a) of, the straight line connecting the positions 311, 312 and the straight line connecting the positions 313, 314 are the tooth straight regions. In addition, in the example shown in (a) of, the positions of the centers of the tooth straight regions are the positions 321, 322. Therefore, Figure 9 In the example shown in (a) of, the positions of the centers of the tooth straight regions are the positions 321, 322. Therefore, Figure 9The width of the tooth 31A shown in (a) is the distance TW between position 321 and position 322.

[0196] exist Figure 9 In the example shown in (b), the straight line connecting positions 315 and 316 and the straight line connecting positions 317 and 318 form the toothed line region. Additionally, in Figure 9 In the example shown in (b), the center of the tooth line region is located at positions 323 and 324. Therefore, Figure 9 The width of the tooth 31B shown in (b) is the distance TW between position 323 and position 324.

[0197] exist Figure 9 In (a), there is an example of a tooth 31A that is parallel to the radial direction, so that the width of the tooth 31A is fixed regardless of any radial position in the tooth straight region.

[0198] On the other hand, Figure 9 In (b), there is an example of a tooth 31B that is radially parallel to the groove. The actual width of the tooth 31B varies depending on any radial position in the tooth straight area. Therefore, as a representative value, the width of the tooth 31B is set as the distance TW between the positions 323 and 324 mentioned above.

[0199] In the above embodiments, by the method described in the <Method for Manufacturing Stator Core>, it is possible to generate a segmented core with the radial direction of the teeth along a direction with excellent magnetic properties.

[0200] Next, an example will be described for a segmented core where the radial direction of the generated teeth is not along the direction of superior magnetic properties. Furthermore, the same methods as those described above in the section on "Methods for Manufacturing Stator Cores" will be appropriately omitted.

[0201] First, in the iron chip production process, iron chips 90 are produced by punching from the development material using a mold.

[0202] Figure 10 This is a diagram used to illustrate the die for developing blanking materials. Furthermore, Figure 10 The development material 80 shown is related to Figure 8 The development material shown is the same electromagnetic steel sheet as 80. In Figure 10 In the diagram, the rolling direction RD and the directions with excellent magnetic properties (ED1, ED2) are indicated corresponding to the developed material 80.

[0203] The stamping device stamps the development material 80 in a manner in which neither the radial direction of the teeth of the iron chip 90 nor the extending direction of the back of the iron core is a direction in which the development material 80 exhibits excellent magnetic properties. Specifically, as follows: Figure 10As shown, the die of the punching device is set so that the radial direction of the teeth of the core piece 90 (single-dotted line L1) is along a direction in which the angle with the rolling direction of the development material 80 is 0°. Further, since the radial direction of the teeth of the core piece 90 is orthogonal to the extension direction of the core back, the radial direction of the teeth is along a direction in which the angle with the rolling direction of the development material 80 is 0°, and thus the extension direction of the core back is set to be along a direction in which the angle with the rolling direction of the development material 80 is 90°.

[0204] Thus, the radial direction of the teeth of the core piece 90 punched by the punching device is along a direction in which the angle with the rolling direction is 0°, and the extension direction of the core back is along a direction in which the angle with the rolling direction is 90°. Further, in the present modification example, the radial direction of the teeth of all the core pieces 90 punched by the punching device is the same direction. Thus, for all the core pieces 90 punched, the radial direction of the teeth is along a direction in which the angle with the rolling direction is 0°, and the extension direction of the core back is along a direction in which the angle with the rolling direction is 90°.

[0205] Next, after aligning the plurality of core pieces 90 punched so that all of them are in the same direction, connecting and stacking them so that the board surfaces are in contact with each other, it is possible to produce a segmented core in which the radial direction of the teeth is not along a direction in which the magnetic characteristics are excellent.

[0206] Here, Figure 10 the core pieces 90 shown in FIG. 1, and Figure 8 the core pieces 40 shown in FIG. 2 are set so that the widths of the teeth are different from each other. Specifically, Figure 10 the widths of the teeth of the core pieces 90 shown in FIG. 1 are set to be wider than Figure 8 the widths of the teeth of the core pieces 40 shown in FIG. 2. In other words, Figure 8 the widths of the teeth of the core pieces 40 shown in FIG. 2 are set to be narrower than Figure 10 the widths of the teeth of the core pieces 90 shown in FIG. 1.

[0207] By stacking Figure 10 the segmented cores of the core pieces 90 shown in FIG. 1, and Figure 8 the segmented cores of the core pieces 40 shown in FIG. 2 in a mixed manner to constitute a stator core, it is possible to constitute a stator core in which the width of the teeth in the radial direction along a direction in which the magnetic characteristics are excellent is narrower than the width of the teeth in the radial direction not along a direction in which the magnetic characteristics are excellent. In this way, by constituting a stator core, it is possible to reduce the deviation of the magnetic flux density within the stator core.

[0208] Further, in the present modification example, in the case where segmented cores of different kinds are present in a mixed manner, the stator core is constituted in such a manner that the product of the width of the teeth of the segmented core and the magnetic flux density of the teeth when excited by a prescribed magnetic field strength is substantially constant for each tooth of all the segmented cores.

[0209] The following example illustrates how the width of a tooth is determined in a roughly constant manner by multiplying the tooth width by the magnetic flux density of the tooth in each tooth of all the divided iron cores.

[0210] First, in a specified rotating electric motor using a stator core, the average magnetic flux density of the teeth is analyzed under specified operating conditions (e.g., specified torque), assuming a fixed width for all teeth. The average magnetic flux density of the teeth is the value obtained by averaging the maximum magnetic flux density at each position within each tooth. The average magnetic flux density can be derived through electromagnetic field analysis based on Maxwell's equations (numerical analysis), or by actually measuring the induced voltage using a probe coil in the fabricated stator core and integrating the induced voltage.

[0211] Next, the average magnetic field strength H [A / m] of the tooth is calculated based on the average magnetic flux density of the tooth. The average magnetic field strength of the tooth can be calculated based on the relative permeability of the development material. Then, based on the material properties of development material A, the magnetic flux density B [T] of the tooth at each angle relative to the rolling direction when energized with the average magnetic field strength of the tooth is calculated. Furthermore, the magnetic flux density of the tooth at each angle relative to the rolling direction can be derived from the BH properties of the development material at the angle relative to the rolling direction.

[0212] In this variation, in the stacking Figure 8 In the segmented iron core of the iron chip 40 shown, the magnetic flux density of the teeth at an angle of 45° to the rolling direction is calculated. Additionally, in the stacked... Figure 10 In the segmented iron core of the iron chip 90 shown, the magnetic flux density of the teeth at an angle of 0° to the rolling direction is calculated. Furthermore, as shown above, the B50 ratio of the developed material is largest when the angle to the rolling direction is 45°, and the B50 ratio decreases as the angle approaches 0° or 90°. Therefore, the magnetic flux density of the teeth at an angle of 45° to the rolling direction is calculated to be larger, while the magnetic flux density of the teeth at an angle of 0° to the rolling direction is calculated to be smaller.

[0213] Next, the optimal tooth width is determined for each angle relative to the rolling direction. Specifically, based on the calculated magnetic flux density of the tooth at each angle relative to the rolling direction, the tooth width is determined in a manner where the product of the tooth width and the magnetic flux density is approximately constant for each tooth.

[0214] Therefore, in the layering Figure 8 In the segmented iron core of the iron chip 40 shown, the width of the teeth is calculated to be narrower in the stacked layers. Figure 10 In the segmented iron core of the iron chip 90 shown, the width of the teeth is calculated to be wider.

[0215] The width of the teeth of the stator core is determined in such a manner that the product of the width of the teeth of each of the divided cores and the magnetic flux density of the teeth when the stator core is excited with a predetermined magnetic field strength is substantially constant for each of the teeth of all of the divided cores. Figure 8 The mold for punching the core piece 40 shown in FIG. 4, and Figure 10 The mold for punching the core piece 90 shown in FIG. 9. The core piece 40 and the core piece 90 are respectively produced by punching the development material with each of the molds designed as described above.

[0216] The divided cores of the core piece 40 shown in FIG. 4 and the divided cores of the core piece 90 shown in FIG. 9 are mixed to constitute the stator core, and the stator core can be constituted in such a manner that the product of the width of the teeth of each of the divided cores and the magnetic flux density of the teeth when the stator core is excited with a predetermined magnetic field strength is substantially constant for each of the teeth of all of the divided cores. Figure 8 Figure 10 The divided cores of the core piece 40 shown in FIG. 4 and the divided cores of the core piece 90 shown in FIG. 9 are mixed to constitute the stator core, and the stator core can be constituted in such a manner that the product of the width of the teeth of each of the divided cores and the magnetic flux density of the teeth when the stator core is excited with a predetermined magnetic field strength is substantially constant for each of the teeth of all of the divided cores.

[0217] As described above, in the present modification example, the stator core in which the divided cores of different kinds are mixed is constituted in such a manner that the product of the width of the teeth of each of the divided cores and the magnetic flux density of the teeth when the stator core is excited with a predetermined magnetic field strength is substantially constant for each of the teeth of all of the divided cores. Therefore, even the stator core in which the divided cores of different kinds are mixed can reduce the deviation of the magnetic flux density and suppress the iron loss. Further, the substantially constant is not limited to the case where it is completely constant, and the range in which the iron loss can be suppressed compared to the comparative example is also included in the substantially constant. Specifically, the substantially constant means that the difference between the maximum value and the minimum value of the product of the width of the teeth and the magnetic flux density of the teeth is within ±5%. For example, in the case where the product of the width of the teeth and the magnetic flux density of the teeth is 1.5 [T], the product of the width of the teeth and the magnetic flux density of the teeth of each of the teeth is within the range of 1.425 [T] to 1.575 [T] (within the range of ±5%).

[0218] Further, in the present modification example, the case where the average magnetic flux density of the teeth when the stator core is operated with a predetermined operating condition (for example, a predetermined torque) is analyzed is described, but the predetermined operating condition can be appropriately selected. For example, an operating condition in which the ratio of the operating time among a plurality of operating conditions assumed is the highest can be set as the predetermined operating condition. In addition, the optimal width of the teeth decided can be further weighted based on the ratio of the operating time of each of the plurality of operating conditions.

[0219] In addition, in the present modification example, the stator core in which two kinds of divided cores are mixed is described, but it is not limited to this case, and can also be applied to a stator core in which three or more kinds of divided cores are mixed.

[0220] The present application has been described above together with various embodiments, but the present application is not limited to these embodiments, and modifications can be made within the scope of the present application.

[0221] Industrial applicability ​

[0222] According to the present application, the magnetic characteristics of a stator core having a plurality of divided cores can be improved. Therefore, the industrial applicability is high.

[0223] Reference Signs

[0224] 10: rotary electric machine

[0225] 21: stator core

[0226] 30: divided core

[0227] 31: tooth portion

[0228] 32: core back portion

[0229] 40: core piece

[0230] 41: tooth

[0231] 42: core back

[0232] 50: rotor

[0233] 51: rotor core

[0234] 52: permanent magnet

[0235] 60: rotation axis

Claims

1. A stator core provided with a plurality of divided cores, characterized in that the plurality of divided cores are configured by laminating core pieces made of an electromagnetic steel sheet, the electromagnetic steel sheet has the following chemical components: contains, in 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, one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total 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: total 0.0000% to 0.0100%, when the content of Mn is [Mn] in mass%, the content of Ni is [Ni] in mass%, the content of Co is [Co] in mass%, the content of Pt is [Pt] in mass%, the content of Pb is [Pb] in mass%, the content of Cu is [Cu] in mass%, the content of Au is [Au] in mass%, the content of Si is [Si] in mass%, and the content of sol. Al is [sol. Al] in mass%, the following formula (1) is satisfied, ([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au]) - ([Si] + [sol. Al]) > 0% (1) the remainder is made of Fe and impurities, the value of B50 in the rolling direction is B50L, the value of B50 in a direction inclined by 45° from the rolling direction is B50D1, the value of B50 in a direction inclined by 90° from the rolling direction is B50C, the value of B50 in a direction inclined by 135° from the rolling direction is B50D2, the following formulae (2) and (4) are satisfied, (B50D1 + B50D2) / 2 > 1.7T (2) (B50D1 + B50D2) / 2 > 1.1 x (B50L + B50C) / 2 (4) the X-ray random intensity ratio of {100} <011> is 5 or more and less than 30, and the sheet thickness is 0.50 mm or less, and either one of the radial direction of the teeth of the core piece of at least one of the plurality of divided cores and the extension direction of the core back is along a direction in which the magnetic properties of the electromagnetic steel sheet are excellent.

2. A stator core provided with a plurality of divided cores, characterized in that the plurality of divided cores are configured by laminating core pieces made of an electromagnetic steel sheet, the electromagnetic steel sheet has the following chemical components: contains, in 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, one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total 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: total 0.0000% to 0.0100%, when the content of Mn is [Mn] in mass%, the content of Ni is [Ni] in mass%, the content of Co is [Co] in mass%, the content of Pt is [Pt] in mass%, the content of Pb is [Pb] in mass%, the content of Cu is [Cu] in mass%, the content of Au is [Au] in mass%, the content of Si is [Si] in mass%, and the content of sol. Al is [sol. Al] in mass%, the following formula (1) is satisfied, ([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au]) - ([Si] + [sol. Al]) > 0% (1) the remainder is made of Fe and impurities, the value of B50 in the rolling direction is B50L, the value of B50 in a direction inclined by 45° from the rolling direction is B50D1, the value of B50 in a direction inclined by 90° from the rolling direction is B50C, the value of B50 in a direction inclined by 135° from the rolling direction is B50D2, the following formulae (2) and (4) are satisfied, (B50D1 + B50D2) / 2 > 1.7T (2) (B50D1 + B50D2) / 2 > 1.1 x (B50L + B50C) / 2 (4) the X-ray random intensity ratio of {100} <011> is 5 or more and less than 30, and the sheet thickness is 0.50 mm or less, and either one of the radial direction of the teeth of the core piece of at least one of the plurality of divided cores and the extension direction of the core back is along a direction in which the magnetic properties of the electromagnetic steel sheet are excellent. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total 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: total 0.0000 to 0.0100%, when the Mn content is [Mn] in mass%, the Ni content is [Ni] in mass%, the Co content is [Co] in mass%, the Pt content is [Pt] in mass%, the Pb content is [Pb] in mass%, the Cu content is [Cu] in mass%, the Au content is [Au] in mass%, the Si content is [Si] in mass%, and the sol. Al content is [sol. Al] in mass%, the following formula (1) is satisfied, ([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au]) - ([Si] + [sol. Al]) > 0%... (1) the remainder is composed of Fe and impurities; when the value of B50 in the rolling direction is B50L, the value of B50 in a direction inclined by 45° from the rolling direction is B50D1, the value of B50 in a direction inclined by 90° from the rolling direction is B50C, and the value of B50 in a direction inclined by 135° from the rolling direction is B50D2, the following formula (3) and formula (6) are satisfied, (B50D1 + B50D2) / 2 > (B50L + B50C) / 2... (3) (B50D1 + B50D2) / 2 > 1.8T... (6) the X-ray random intensity ratio of {100} < 011 > is 5 or more and less than 30, and the sheet thickness is 0.50 mm or less; either one of the radial direction of the tooth of the core piece of at least one of the plurality of divided cores and the extension direction of the core back is along the direction in which the magnetic properties of the electromagnetic steel sheet are excellent.

3. The stator core according to claim 1, characterized in that, the following formula (5) is satisfied, (B50D1 + B50D2) / 2 > 1.2 x (B50L + B50C) / 2... (5).

4. The stator core according to claim 1, characterized in that, one or more selected from the group consisting of 0.020 to 0.400% of Sn and 0.020 to 0.400% of Sb is contained.

5. The stator core according to claim 2, characterized in that, one or more selected from the group consisting of 0.020 to 0.400% of Sn and 0.020 to 0.400% of Sb is contained.

6. The stator core according to claim 1, characterized in that, in the electromagnetic steel sheet, the direction in which the magnetic properties are excellent is a direction in which the angle with the rolling direction of the electromagnetic steel sheet is 45° and 135°; the radial direction of the tooth is along a direction in which the angle with the rolling direction is either one of 45° and 135°; The extension direction of the core back is in any one of the directions in which the angle with the rolling direction is 45° and 135°.

7. The stator core according to any one of claims 1 to 6, characterized in that In all of the core pieces of the plurality of divided cores, either the radial direction of the teeth or the extension direction of the core back is in the direction in which the magnetic properties of the electromagnetic steel sheet are excellent.

8. The stator core according to any one of claims 1 to 6, characterized in that The plurality of divided cores each have a tooth portion; The width of the tooth portion in the direction in which the magnetic properties are excellent is narrower than the width of the tooth portion not in the direction in which the magnetic properties are excellent.

9. The stator core according to claim 8, characterized in that The product of the width of the tooth portion and the magnetic flux density of the tooth portion when excited by a prescribed magnetic field strength is substantially constant in each tooth portion of the plurality of divided cores.

10. A rotary electric machine characterized by comprising the stator core according to any one of claims 1 to 9. ​

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