Specification
Title of Invention: Stator Core and Rotating Electric Machine
Technical field
[0001]
　The present invention relates to stator cores and rotating electric machines. In particular, it is suitable for use in a stator core having a plurality of split cores.
　This application claims priority based on Japanese Patent Application No. 2019-206648 filed in Japan on November 15, 2019, the contents of which are incorporated herein.
Background technology
[0002]
　2. Description of the Related Art As a stator core (iron core) of a rotary electric machine, a plurality of split cores arranged along the circumferential direction is known.
[0003]
　In Patent Document 1, a core of a motor is divided into individual laminated core pieces by a dividing surface, and each laminated core piece is composed of a unidirectional magnetic steel sheet or a bidirectional magnetic steel sheet. It is disclosed that windings are wound on the laminated core pieces through an insulating portion, and that the easy magnetization direction is determined for each laminated core piece and laminated. According to such a motor, the magnetic flux passing through the laminated core pieces always flows in the direction of easy magnetization of the grain-oriented electrical steel sheets, and changes in the direction of the magnetic flux flowing in the pole teeth and gaps during rotation are small. , iron loss, excitation current, cogging torque, induced voltage distortion and torque ripple can be reduced.
[0004]
　Patent Literature 2 discloses a motor having a stator core in which a plurality of laminated cores having radially extending tooth portions are arranged in the circumferential direction. The laminated core has a plurality of plate-like core pieces laminated in the plate thickness direction. The core piece is made of a non-oriented electrical steel sheet, and the rolling direction of the core piece is inclined with respect to the radial direction. Further, it is disclosed that the laminated core is formed by laminating core pieces having the same inclination, and that at least a pair of laminated cores adjacent in the circumferential direction have opposite inclinations. Such a motor can reduce cogging torque and torque ripple.
prior art documents
patent literature
[0005]
Patent Document 1: Japanese Patent Laid-Open No. 8-47185
Patent Document 2: International Publication No. 2017/090571
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0006]
　However, neither Patent Document 1 nor Patent Document 2 discusses the electromagnetic steel sheet. Therefore, the conventional stator core having a plurality of split cores has room for improvement in improving the magnetic properties.
[0007]
　An object of the present invention is to improve the magnetic properties of a stator core having a plurality of split cores.
Means to solve problems
[0008]
　In order to solve the above problems, the present invention adopts the following configurations.
　(1) A stator core according to an aspect of the present invention is a stator core including a plurality of split cores, wherein the plurality of split cores are configured by laminating core pieces made of electromagnetic steel sheets, and the electromagnetic steel sheets are % by 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, and Au : 2.50% to 5.00% in total, 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: 0.0000% to 0.0100% in total, Mn content (mass %) is [Mn], Ni content (mass%) is [Ni], Co content (mass%) is [Co], Pt content (mass%) is [Pt], Pb content (mass%) [Pb], Cu content (mass%) [Cu], Au content (mass%) [Au], Si content (mass%) [Si], sol. The Al content (% by mass) is measured as [sol. Al], the following formula (1) is satisfied, the balance is Fe and impurities, and the B50 value in the rolling direction is B50L, and the B50 value in the direction tilted 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 expressions (2) and (3) are satisfied. , {100} <011> has an X-ray random intensity ratio of 5 or more and less than 30, a plate thickness of 0.50 mm or less, and at least one of the plurality of split cores has a core piece of a tooth. Both the radial direction and the extending direction of the core-back are along the direction in which the magnetic steel sheet has excellent magnetic properties.
　([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])−([Si]+[sol.Al])>0% (1)
　(B50D1+B50D2)/2>1.7T (2)
　(B50D1+B50D2)/2>(B50L+B50C)/2 (3)
　Here, magnetic flux density B50 means excitation at a magnetic field strength of 5000A/m. is the magnetic flux density when
　(2) The stator core described in (1) above may satisfy the following expression (4).
　(B50D1+B50D2)/2>1.1×(B50L+B50C)/2 (4)
　(3) The stator core described in (1) above may satisfy the following expression (5).
　(B50D1+B50D2)/2>1.2×(B50L+B50C)/2 (5)
　(4) The stator core described in (1) above may satisfy the following expression (6).
　(B50D1+B50D2)/2>1.8T (6)
　(5) In the stator core according to (1) above, the magnetic steel sheet has a direction in which the excellent magnetic properties are obtained at an angle from the rolling direction of the magnetic steel sheet. 45° and 135°, the radial direction of the teeth is along one of the angles 45° and 135° from the rolling direction, and the extending direction of the core back is the direction of the It may be along any other of the 45° and 135° angles from the rolling direction.
　(6) In the stator core according to any one of (1) to (5) above, the plurality of split cores extend in the radial direction of the teeth and the core back in all the core pieces of the split cores. Any of the directions may be along the direction in which the magnetic steel sheet has excellent magnetic properties.
　(7) In the stator core according to any one of (1) to (5) above, each of the plurality of split cores has a tooth portion, and the plurality of tooth portions are aligned in a direction having excellent magnetic properties. The width of the teeth along the direction may be narrower than the width of the teeth not along the direction in which the magnetic properties are excellent.
　(8) In the stator core according to (7) above, the product of the width of the tooth portion and the magnetic flux density of the tooth portion when excited with a predetermined magnetic field intensity is the value of each tooth of the plurality of split cores. It may be substantially constant in parts.
　(9) A rotary electric machine according to an aspect of the present invention includes the stator core according to any one of (1) to (8) above.
Effect of the invention
[0009]
　According to the aspect of the present invention, it is possible to improve the magnetic properties of a stator core having a plurality of split cores.
Brief description of the drawing
[0010]
1 is a diagram showing an example of the configuration of a rotating electrical machine; [0012]FIG.
2 is a diagram showing an example of the configuration of a split core; FIG.
3 is a diagram showing an example of a configuration of a core piece; FIG.
4] A graph showing an example of the relationship between the B50 ratio and the angle from the rolling direction. [FIG.
5 is a graph showing an example of the relationship between the W15/50 ratio and the angle from the rolling direction; FIG.
6 is a graph showing an example of the relationship between the W15/100 ratio and the angle from the rolling direction; FIG.
7 is a diagram showing an example of the relationship between the rolling direction and the direction with the best magnetic properties. FIG.
8] A diagram for explaining a mold according to an embodiment of the present invention. [FIG.
9 is a diagram for explaining the width of a tooth portion; FIG.
10] A diagram for explaining a mold according to a modification. [FIG.
MODE FOR CARRYING OUT THE INVENTION
[0011]

　First, magnetic steel sheets used for split cores of the embodiments described later will be described.
　Here, the chemical composition of the non-oriented electrical steel sheet of the present embodiment, which is an example of the electrical steel sheet used for the split core of the embodiment, and the steel material used in the manufacturing method thereof will be described. In the following description, "%", which is the unit of content of each element contained in the non-oriented electrical steel sheet or steel material of the present embodiment, means "% by mass" unless otherwise specified. In addition, the numerical limits described between "-" include the lower limit and the upper limit. Any numerical value indicated as "less than" or "greater than" excludes that value from the numerical range. Non-oriented electrical steel sheets and steel materials have a chemical composition that can cause ferrite-austenite transformation (hereinafter, α-γ transformation), and are 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, and Au : 2.50% to 5.00% in total, 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: 0.0000% to 0.0100% in total, the balance being Fe and impurities It has a chemical composition consisting of Furthermore, Mn, Ni, Co, Pt, Pb, Cu, Au, Si and sol. The content of Al satisfies the predetermined condition described later. Examples of impurities include those contained in raw materials such as ores and scraps, and those contained in manufacturing processes.
[0012]
　<>
　C increases core loss and causes magnetic aging. Therefore, the lower the C content, the better. Such a phenomenon is remarkable when the C content exceeds 0.0100%. Therefore, the C content should be 0.0100% or less. A reduction in the C content also contributes to the uniform improvement of the magnetic properties in all directions within the plate surface. Although the lower limit of the C content is not particularly limited, it is preferably 0.0005% or more in consideration of the cost of decarburization treatment during refining.
[0013]
　<>
　Si increases electrical resistance, reduces eddy current loss, reduces iron loss, increases yield ratio, improve workability. If the Si content is less than 1.50%, these effects cannot be sufficiently obtained. Therefore, the Si content should be 1.50% or more. On the other hand, if the Si content exceeds 4.00%, the magnetic flux density is lowered, the punching workability is lowered due to an excessive increase in hardness, and cold rolling becomes difficult. Therefore, the Si content should be 4.00% or less.
[0014]
　<< sol. Al: 0.0001% to 1.0% >>
　sol. Al increases electrical resistance, reduces eddy current loss, and reduces iron loss. sol. Al also contributes to improving the relative magnitude of the magnetic flux density B50 with respect to the saturation magnetic flux density. Here, the magnetic flux density B50 is the magnetic flux density when excited with a magnetic field strength of 5000 A/m. sol. If the Al content is less than 0.0001%, these effects cannot be sufficiently obtained. Al also has the effect of promoting desulfurization in steelmaking. Therefore, sol. Al content shall be 0.0001% or more. On the other hand, sol. If the Al content exceeds 1.0%, the magnetic flux density is lowered, the yield ratio is lowered, and the punching workability is lowered. Therefore, sol. Al content is 1.0% or less.
[0015]
　<>
　S is not an essential element but is contained as an impurity in steel, for example. S inhibits recrystallization and grain growth during annealing due to the precipitation of fine MnS. Therefore, the lower the S content, the better. The increase in iron loss and the decrease in magnetic flux density due to the inhibition of recrystallization and grain growth are remarkable when the S content exceeds 0.0100%. Therefore, the S content is set to 0.0100% or less. Although the lower limit of the S content is not particularly limited, it is preferably 0.0003% or more in consideration of the cost of desulfurization treatment during refining.
[0016]
　<>
　Since N, like C, deteriorates the magnetic properties, the lower the N content, the better. Therefore, the N content should be 0.0100% or less. Although the lower limit of the N content is not particularly limited, it is preferably 0.0010% or more in consideration of the cost of denitrification treatment during refining.
[0017]
　<>
　These elements cause α-γ transformation These elements must be contained in a total amount of 2.50% or more because they are elements necessary for On the other hand, if the total content exceeds 5.00%, the cost increases and the magnetic flux density may decrease. Therefore, the total content of these elements is set to 5.00% or less.
[0018]
　Further, the following conditions are satisfied as conditions under which the α-γ transformation can occur. That is, [Mn] is the Mn content (% by mass), [Ni] is the Ni content (% by mass), [Co] is the Co content (% by mass), [Pt] is the Pt content (% by mass), Pb content (% by mass) is [Pb], Cu content (% by mass) is [Cu], Au content (% by mass) is [Au], Si content (% by mass) is [Si], sol. The Al content (% by mass) is measured as [sol. Al], it is preferable that the following formula (1) is satisfied in terms of % by mass.
　([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])−([Si]+[sol.Al])>0% (1)
[0019]
　If the above formula (1) is not satisfied, the α-γ transformation does not occur, resulting in a low magnetic flux density.
[0020]
　<>
　Sn and Sb after cold rolling and recrystallization improve the texture of the material to increase its magnetic flux density. Therefore, these elements may be contained as necessary, but if contained excessively, they embrittle the steel. Therefore, both Sn content and Sb content are set to 0.400% or less. Also, P may be contained in order to ensure the hardness of the steel sheet after recrystallization, but if contained excessively, it causes the embrittlement of the steel. Therefore, the P content should be 0.400% or less. In the case of imparting further effects such as magnetic properties as described above, 0.020% to 0.400% Sn, 0.020% to 0.400% Sb, and 0.020% to 0.400% % of one or more selected from the group consisting of P.
[0021]
　<>
　Mg, Ca, Sr , Ba, Ce, La, Nd, Pr, Zn and Cd react with S in the molten steel during casting to form precipitates of sulfides and/or oxysulfides. Hereinafter, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd may be collectively referred to as "coarse precipitate forming elements". The grain size of coarse precipitate-forming elements is about 1 μm to 2 μm, which is much larger than the grain size (about 100 nm) of fine precipitates such as MnS, TiN, and AlN. For this reason, these fine precipitates adhere to the precipitates of the coarse precipitate-forming element and are less likely to inhibit recrystallization and grain growth during intermediate annealing. In order to sufficiently obtain these effects, the total content of these elements is preferably 0.0005% or more. However, if the total amount of these elements exceeds 0.0100%, the total amount of sulfides or oxysulfides or both becomes excessive, inhibiting recrystallization and grain growth during intermediate annealing. Therefore, the total content of coarse precipitate-forming elements is set to 0.0100% or less.
[0022]
<>
　Next, the texture of the non-oriented electrical steel sheet of this embodiment will be described. Although the details of the manufacturing method will be described later, the non-oriented electrical steel sheet of the present embodiment has a chemical composition that can cause α-γ transformation, and the structure is refined by rapid cooling immediately after the finish rolling in hot rolling. It becomes a structure in which {100} crystal grains grow. As a result, the non-oriented electrical steel sheet of this embodiment has an integrated strength of 5 to 30 in the {100}<011> orientation, and the magnetic flux density B50 in the direction of 45° to the rolling direction is particularly high. Thus, although the magnetic flux density is high in a specific direction, a high magnetic flux density is obtained on average in all directions as a whole. If the {100}<011> direction integration intensity is less than 5, the {111}<112> direction integration intensity, which lowers the magnetic flux density, increases, and the overall magnetic flux density decreases. In addition, the production method in which the integrated strength in the {100}<011> orientation exceeds 30 requires a thick hot-rolled sheet, which poses a problem of difficulty in production.
[0023]
　The integrated intensity of the {100}<011> orientation can be measured by X-ray diffraction or electron backscatter diffraction (EBSD). Since the angle of reflection of X-rays and electron beams from a sample differs for each crystal orientation, the crystal orientation intensity can be obtained from the reflection intensity and the like with reference to a randomly oriented sample. The integrated intensity of the {100}<011> orientation of the preferred non-oriented electrical steel sheet of the present embodiment is 5 to 30 in terms of the X-ray random intensity ratio. At this time, a value obtained by measuring the crystal orientation by EBSD and converting it into an X-ray random intensity ratio may be used.
[0024]
<>
　Next, the thickness of the non-oriented electrical steel sheet of this embodiment will be described. The thickness of the non-oriented electrical steel sheet of this 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 should be 0.50 mm or less.
[0025]
<>
　Next, the magnetic properties of the non-oriented electrical steel sheet of this embodiment will be described. When examining the magnetic properties, the value of B50, which is the magnetic flux density of the non-oriented electrical steel sheet of this embodiment, is measured. In the manufactured non-oriented electrical steel sheet, it is impossible to distinguish between one rolling direction and the other. Therefore, in this embodiment, the rolling direction refers to both one and the other. 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 Assuming that the value is B50D2, the anisotropy of magnetic flux density is observed such that B50D1 and B50D2 are the highest and B50L and B50C are the lowest.
[0026]
　Here, for example, when considering the omnidirectional (0 ° to 360 °) distribution of the magnetic flux density with the clockwise (or counterclockwise) direction as the positive direction, the rolling direction is 0 ° (one direction) and 180 ° ° (other direction), B50D1 has B50 values ​​of 45° and 225°, and B50D2 has B50 values ​​of 135° and 315°. Similarly, B50L results in B50 values ​​of 0° and 180°, and B50C results in B50 values ​​of 90° and 270°. The 45° and 225° B50 values ​​are in close agreement, and the 135° and 315° B50 values ​​are in close agreement. However, B50D1 and B50D2 may not match exactly because it may not be easy to make the magnetic properties the same in actual manufacturing. Similarly, the 0° and 180° B50 values ​​are closely matched, the 90° and 270° B50 values ​​are closely matched, while the B50L and B50C are closely matched. may not. The non-oriented electrical steel sheet of this embodiment satisfies the following expressions (2) and (3) using the average values ​​of B50D1 and B50D2 and the average values ​​of B50L and B50C.
　(B50D1+B50D2)/2>1.7T (2)
　(B50D1+B50D2)/2>(B50L+B50C)/2 (3)
[0027]
　In this way, when the magnetic flux density is measured, the average value of B50D1 and B50D2 is 1.7 T or more as in equation (2), and high anisotropy in magnetic flux density is confirmed as in equation (3). .
[0028]
　Furthermore, in addition to satisfying the formula (1), it is preferable that the anisotropy of the magnetic flux density is higher than that of the formula (3), as in the following formula (4).
　(B50D1+B50D2)/2>1.1×(B50L+B50C)/2 (4)
　Furthermore, as in the following equation (5), it is preferable that the anisotropy of the magnetic flux density is higher.
　(B50D1+B50D2)/2>1.2×(B50L+B50C)/2 (5)
　Furthermore, it is preferable that the average value of B50D1 and B50D2 is 1.8 T or more, as in the following equation (6).
　(B50D1+B50D2)/2>1.8T (6)
[0029]
　Note that the above 45° is a theoretical value, and since it may not be easy to match it to 45° in actual manufacturing, it includes values ​​that do not strictly match 45°. This is the same for 0°, 90°, 135°, 180°, 225°, 270° and 315°.
[0030]
　The magnetic flux density can be measured by cutting out a 55 mm square sample from the direction of 45°, 0°, etc. with respect to the rolling direction and using a single-plate magnetometer.
[0031]
<>
　Next, an example of a method for manufacturing the non-oriented electrical steel sheet of the present embodiment will be described. When manufacturing the non-oriented electrical 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), rolling), finish annealing (third annealing), stress relief annealing (second annealing), and the like are performed.
[0032]
　First, the steel materials described above are heated and hot rolled. The steel material is, for example, a slab produced by normal continuous casting. Rough rolling and finish rolling of hot rolling are performed at a temperature in the γ region (Ar1 temperature or higher). That is, hot rolling is performed so that the finish rolling temperature is Ar1 temperature or higher and the coiling temperature is higher than 250° C. and lower than or equal to 600° C. As a result, the subsequent cooling transforms austenite into ferrite, thereby refining the structure. When cold rolling is applied after the fine grains are formed, bulging recrystallization (hereinafter referred to as bulging) is likely to occur, so that {100} crystal grains, which are normally difficult to grow, can be easily grown.
[0033]
　Further, when manufacturing the non-oriented electrical steel sheet of the present embodiment, the temperature (finishing temperature) when passing through the final pass of finish rolling is Ar1 temperature or more, and the coiling temperature is more than 250 ° C. and 600 ° C. or less. and The crystal structure is refined by transforming from austenite to ferrite. By refining the crystal structure in this manner, bulging can be easily generated through subsequent cold rolling and intermediate annealing.
[0034]
　After that, the hot-rolled steel sheet is wound up without being annealed, pickled, and cold-rolled to the hot-rolled steel sheet. In cold rolling, it is preferable to set the rolling reduction to 80% to 95%. If the rolling reduction is less than 80%, bulging is less likely to occur. When the rolling reduction exceeds 95%, the {100} crystal grains tend to grow due to the subsequent bulging, but the hot-rolled steel sheet must be thickened, which makes it difficult to coil the hot-rolled steel, making the operation difficult. easier. The draft of cold rolling is more preferably 86% or more. Bulging is more likely to occur when the rolling reduction of cold rolling is 86% or more.
[0035]
　After cold rolling is completed, intermediate annealing is subsequently performed. When manufacturing the non-oriented electrical steel sheet of the present embodiment, intermediate annealing is performed at a temperature that does not transform into austenite. That is, it is preferable to set the temperature of the intermediate annealing to less than the Ac1 temperature. Such intermediate annealing causes bulging and facilitates the growth of {100} crystal grains. Also, the time for the intermediate annealing is preferably 5 seconds to 60 seconds.
[0036]
　After intermediate annealing is completed, skin pass rolling is performed next. As described above, when skin-pass rolling and annealing are performed in a state where bulging occurs, {100} crystal grains grow further starting from the portion where bulging occurs. This is because the {100}<011> crystal grains are less likely to be strained by skin pass rolling, and the {111}<112> crystal grains are more likely to be strained. This is because the 011> crystal grains eat the {111}<112> crystal grains with the difference in strain as a driving force. This erosion phenomenon caused by the strain difference as a driving force is called strain-induced grain boundary migration (SIBM). The rolling reduction of skin pass rolling is preferably 5% to 25%. If the rolling reduction is less than 5%, the amount of strain is too small, so SIBM does not occur in subsequent annealing, and the {100}<011> crystal grains do not grow. On the other hand, if the rolling reduction exceeds 25%, the amount of strain becomes too large, and recrystallization nucleation (hereinafter referred to as nucleation) in which new crystal grains are generated from {111}<112> crystal grains occurs. Since most of the grains produced in this nucleation are {111}<112> crystal grains, the magnetic properties deteriorate.
[0037]
　After skin-pass rolling, finish annealing is performed to release strain and improve workability. The finish annealing is similarly performed at a temperature at which the steel does not transform into austenite, and the finish annealing temperature is lower than the Ac1 temperature. By performing finish annealing in this way, the {100}<011> crystal grains eat away the {111}<112> crystal grains, and the magnetic properties can be improved. Also, the time at which the temperature reaches 600° C. to Ac1 during finish annealing is set within 1200 seconds. If the annealing time is too short, most of the strain introduced by the skin pass remains, and warping occurs when punching a complicated shape. On the other hand, if the annealing time is too long, the crystal grains become too coarse, resulting in large sag during punching and poor punching accuracy.
[0038]
　After the finish annealing is completed, the non-oriented electrical steel sheet is formed and processed to obtain a desired steel member. Then, the steel member made of the non-oriented electrical steel sheet is subjected to strain relief annealing in order to remove strain and the like caused by forming and the like (for example, punching). In the present embodiment, in order to generate SIBM below the Ac1 temperature and make the crystal grain size coarse, the temperature of stress relief annealing is set to, for example, about 800° C., and the stress relief annealing time is about 2 hours. and Magnetic properties can be improved by stress relief annealing.
[0039]
　In the non-oriented electrical steel sheet (steel member) of the present embodiment, among the above-described manufacturing methods, mainly by performing finish rolling at a temperature of Ar1 or higher in the hot rolling process, the high B50 of the formula (1) and the above (2) excellent anisotropy is obtained. Further, by setting the rolling reduction to about 10% in the skin-pass rolling process, more excellent anisotropy of the formula (4) can be obtained.
　In this embodiment, the Ar1 temperature is obtained from the change in thermal expansion of the steel material (steel plate) during cooling at an average cooling rate of 1° C./sec. Further, in this embodiment, the Ac1 temperature is obtained from the change in thermal expansion of the steel material (steel plate) being heated at an average heating rate of 1° C./sec.
[0040]
　As described above, a steel member made of the non-oriented electrical steel sheet of the present embodiment can be manufactured.
[0041]
　Next, the non-oriented electrical steel sheet of this embodiment will be specifically described with reference to examples. The examples shown below are merely examples of non-oriented electrical steel sheets, and non-oriented electrical steel sheets are not limited to the following examples.
[0042]
<>
　An ingot having the components shown in Tables 1 and 2 below was produced by casting molten steel. Here, the left side of the equation represents the value of the left side of the above equation (1). After that, the produced ingot was heated to 1150° C. and hot rolled so as to have a plate thickness of 2.5 mm. After finish rolling, the hot-rolled steel sheet was water-cooled and wound up. The temperature (finishing temperature) at the stage of the final pass of finish rolling at this time was 830° C., and all of them were higher than the Ar1 temperature. In addition, No. 1 where γ-α transformation does not occur. For No. 108, the finishing temperature was 850°C. Further, the winding temperature was set under the conditions shown in Table 1.
[0043]
　Next, the hot-rolled steel sheets were pickled to remove scales, and rolled at the rolling reduction after cold rolling shown in Table 1. Then, intermediate annealing was performed at 700° C. for 30 seconds in a non-oxidizing atmosphere. Then, it was rolled at the second cold rolling (skin pass rolling) reduction shown in Table 1.
[0044]
　Next, in order to examine the magnetic properties, after the second cold rolling (skin pass rolling), final annealing was performed at 800°C for 30 seconds, and a 55 mm square sample was prepared by shearing, followed by annealing at 800°C for 2 hours. Stress relief annealing was performed and the magnetic flux density B50 was measured. A sample of 55 mm square was taken in two directions of 0° and 45° in the rolling direction. These two types of samples were measured, and the magnetic flux densities B50 at 0°, 45°, 90°, and 135° with respect to the rolling direction were B50L, B50D1, B50C, and B50D2, respectively.
[0045]
[table 1]

[0046]
[Table 2]

[0047]
　表１から表２中の下線は、本発明の範囲から外れた条件を示している。発明例であるＮｏ．１０１～Ｎｏ．１０７、Ｎｏ．１０９～Ｎｏ．１１１、Ｎｏ．１１４～Ｎｏ．１３０は、いずれも４５°方向および全周平均共に磁束密度Ｂ５０は良好な値であった。ただし、Ｎｏ．１１６とＮｏ．１２７は適切な巻取り温度から外れたため、磁束密度Ｂ５０はやや低かった。Ｎｏ．１２９とＮｏ．１３０は冷間圧延の圧下率が低かったため、同等の成分、巻取り温度であるＮｏ．１１８と比べて磁束密度Ｂ５０はやや低かった。一方、比較例であるＮｏ．１０８はＳｉ濃度が高く、式左辺の値が０以下であり、α－γ変態しない組成であったことから、磁束密度Ｂ５０はいずれも低かった。比較例であるＮｏ．１１２は、スキンパス圧延率を低くしたため、｛１００｝＜０１１＞強度を５未満であり、磁束密度Ｂ５０がいずれも低かった。比較例であるＮｏ．１１３は｛１００｝＜０１１＞強度が３０以上となり、本発明から外れている。Ｎｏ．１１３は熱間圧延板の厚みが７ｍｍもあったため、操業しづらいという難点があった。
[0048]
<<第２の実施例>>
　溶鋼を鋳造することにより、以下の表３に示す成分のインゴットを作製した。その後、作製したインゴットを１１５０℃まで加熱して熱間圧延を行い、板厚が２．５ｍｍになるように圧延した。そして、仕上げ圧延終了後に水冷し熱間圧延鋼板を巻き取った。この時の仕上げ圧延の最終パスの段階での仕上温度は８３０℃であり、すべてＡｒ１温度より大きい温度だった。
[0049]
　Next, the hot-rolled steel sheet was pickled to remove scales, and cold-rolled until the sheet thickness reached 0.385 mm. Then, intermediate annealing was performed in a non-oxidizing atmosphere, and the temperature of the intermediate annealing was controlled so that the recrystallization rate was 85%. Then, the second cold rolling (skin pass rolling) was performed until the sheet thickness reached 0.35 mm.
[0050]
　Next, in order to examine the magnetic properties, after the second cold rolling (skin pass rolling), final annealing was performed at 800°C for 30 seconds, and a 55 mm square sample was prepared by shearing, followed by annealing at 800°C for 2 hours. After strain relief annealing, magnetic flux density B50 and core loss W10/400 were measured. The magnetic flux density B50 was measured in the same procedure as in the first example. On the other hand, iron loss W10/400 was measured as energy loss (W/kg) generated in the sample when an alternating magnetic field of 400 Hz was applied so that the maximum magnetic flux density was 1.0T. Iron loss was the average value of the results of measurements at 0°, 45°, 90° and 135° with respect to the rolling direction.
[0051]
[Table 3]

[0052]
[Table 4]

[0053]
　No. 201 to No. All No. 214 are invention examples, and all of them had good magnetic properties. In particular, No. 202-No. 204 is No. 201, No. 205-No. The magnetic flux density B50 is higher than that of No. 214. 205-No. 214 is No. 201 to No. Iron loss W10/400 was lower than that of 204.
[0054]
　In the following description, the direction inclined by 45° from the rolling direction, which is described in the description of , is referred to as an angle of 45° from the rolling direction as necessary, and the rolling A direction tilted 135° from the direction is optionally referred to as an angle of 135° from the rolling direction. In addition, a direction inclined by θ° from the rolling direction is referred to as a direction forming an angle of θ° with the rolling direction, as required. Thus, the direction inclined θ° from the rolling direction and the direction forming an angle θ° with the rolling direction have the same meaning.
[0055]
　The non-oriented electrical steel sheet described above was newly developed by the present inventors, and has the best magnetic properties in two directions at angles of 45° and 135° from the rolling direction. On the other hand, the magnetic properties are the worst in the two directions with angles of 0° and 90° from the rolling direction. Here, 45° and 135° are theoretical values, and it may not be easy to match 45° and 135° in actual manufacturing. Therefore, theoretically, if the directions with the best magnetic properties are two directions with angles of 45° and 135° from the rolling direction, in an actual non-oriented electrical steel ° includes those that do not strictly match 45° and 135°. This is the same at 0° and 90°. Theoretically, the magnetic properties in the two directions where the magnetic properties are the best are the same, but in actual manufacturing, it may not be easy to make the magnetic properties in the two directions the same. Therefore, theoretically, if the magnetic properties in the two directions in which the magnetic properties are the best are the same, the term "same" includes those that are not exactly the same. This is the same for the two directions where the magnetic properties are the worst. A clockwise angle is defined as a positive angle.
[0056]
In
　order to effectively utilize the characteristics of the non-oriented electrical steel sheet, the present inventors have studied forming a stator core with a plurality of split cores, and found the following embodiments.
　An embodiment of the present invention will be described below with reference to the drawings. In the following description, unless otherwise specified, the magnetic steel sheet is the non-oriented magnetic steel sheet described in the section. In addition, in the following description, the same (matching) in length, direction, position, etc. means (strictly) the same (matching), as well as within a range that does not deviate from the gist of the invention (for example, , within the range of error occurring in the manufacturing process) and being the same (matching).
　In this embodiment, an electric motor, specifically an AC motor, more specifically a synchronous motor, and even more specifically a permanent magnet field type electric motor will be described as an example of the rotating electric machine. Electric motors of this type are suitably employed in, for example, electric vehicles.
[0057]
　FIG. 1 is a diagram showing an example of the configuration of a rotating electrical machine 10. As shown in FIG. FIG. 1 is a diagram (plan view) of a rotating electrical machine as seen from a direction parallel to the axis of the rotating electrical machine. The XYZ coordinates shown in FIG. 1 indicate the orientation relationship in the figure.
　As shown in FIG. 1 , the rotating electrical machine 10 includes a stator 20 and a rotor 50 . Stator 20 and rotor 50 are housed in a case (not shown). Also, the stator 20 is fixed to the case.
　In this embodiment, an inner rotor type in which the rotor 50 is positioned inside the stator 20 is employed as the rotating electric machine 10 . However, as rotating electric machine 10 , an outer rotor type in which rotor 50 is positioned outside stator 20 may be employed. Further, in this embodiment, the rotary electric machine 10 is a three-phase AC motor with 10 poles and 12 slots. However, the number of poles, the number of slots, the number of phases, etc. can be changed as appropriate.
[0058]
　The stator 20 includes a stator core 21 and coils (not shown).
　In the following description, the axial direction of the stator core 21 (the direction along the central axis O of the stator core 21 (the Z-axis direction)) will be referred to as the axial direction as necessary. Moreover, the radial direction of the stator core 21 (the direction perpendicular to the central axis O of the stator core 21) is referred to as the radial direction as necessary. Moreover, the circumferential direction of the stator core 21 (the direction in which the stator core 21 revolves around the central axis O) is referred to as the circumferential direction as necessary.
[0059]
　Stator core 21 includes a plurality of split cores 30 . Specifically, in the stator core 21 of the present embodiment, 12 split cores 30 are arranged in the circumferential direction, that is, in the direction in which they revolve around the central axis O. As shown in FIG. The split cores 30 of this embodiment have the same shape and size. Each split core 30 has a tooth portion 31 and a core back portion 32 .
[0060]
　The windings of the stator 20 are wound around the tooth portions 31 . The tooth portions 31 protrude radially inward from the core back portion 32 . That is, the tooth portions 31 protrude toward the central axis O along the radial direction. The tooth portions 31 are arranged at equal intervals in the circumferential direction. In this embodiment, twelve teeth 31 are provided at intervals of 30° around the central axis O of the stator core 21 . The windings of the stator 20 may be concentratedly wound or distributedly wound.
　The core back portion 32 is formed in an arc shape. By arranging the plurality of split cores 30 in the circumferential direction, the entire core back portion 32 is formed in an annular shape.
[0061]
　FIG. 2 is a diagram showing an example of the configuration of the split core 30. As shown in FIG. FIG. 2 is an oblique view (perspective view) of one of the plurality of split cores 30 included in the stator core 21 .
　The split core 30 is configured by laminating core pieces 40 made of electromagnetic steel sheets. Each core piece 40 is plate-shaped and has the same shape and size. By stacking the core pieces 40 in the same direction in the plate thickness direction, the split cores 30 have the same shape in the axial direction, that is, along the central axis O. As shown in FIG.
[0062]
　FIG. 3 is a diagram showing an example of the configuration of the core piece 40. As shown in FIG. FIG. 3 is a plan view of one of the plurality of core pieces 40 forming the split core 30 as viewed along the central axis O. As shown in FIG. As shown in FIG. 3 , the core piece 40 has teeth 41 and core backs 42 .
[0063]
　The teeth 41 constitute the teeth portion 31 of the split core 30 by stacking the core pieces 40 . The teeth 41 each have a tooth base portion 41a radially extending from the center of the core back 42 in the circumferential direction, and a flange portion 41b positioned at the tip of the tooth base portion 41a. When the rotary electric machine 10 is configured using the split core 30 , the collar portion 41 b faces the rotor 50 .
[0064]
　The core back 42 constitutes the core back portion 32 of the split core 30 by stacking the core pieces 40 . The core back 42 has a protrusion 43a protruding in the circumferential direction at one end in the circumferential direction and a recess 43b recessed in the circumferential direction at the other end in the circumferential direction. The convex portion 43a and the concave portion 43b have mutually inverted shapes. When the plurality of split cores 30 are arranged in the circumferential direction, the protrusions 43a are fitted with the recesses 43b of the adjacent core pieces 40, and the recesses 43b are fitted with the protrusions 43a of the adjacent core pieces 40. FIG.
[0065]
　In the core piece 40, the radial direction of the teeth 41 and the extending direction of the core back 42 are orthogonal. The radial direction of the teeth 41 is a direction along a line that is parallel to the plate surface of the teeth 41 and passes through the center of the teeth 41 in the circumferential direction, as indicated by the dashed-dotted line L1 in FIG. Alternatively, the radial direction of the teeth 41 refers to a position P that is parallel to the plate surface of the teeth 41 and bisects the length of the outer circumference of the core back 42 and the center of the circle on the outer circumference of the core back 42. It is the direction along the connecting line.
　On the other hand, the extending direction of the core back 42 is a direction orthogonal to the radial direction of the teeth 41 . That is, the extending direction of the core-back 42 is a direction along a tangent to the outer circumference of the core-back 42 at a position P between the one-dot chain line L1 and the outer circumference of the core-back 42, as shown by the one-dot chain line L2 in FIG. . Alternatively, the extension direction of the core-back 42 is a direction along a tangent to the outer circumference of the core-back 42 at a position P that bisects the length of the outer circumference of the core-back 42 .
[0066]
　Returning to FIG. 1 , the rotor 50 is arranged radially inside the stator core 21 . The rotor 50 includes a rotor core 51 , multiple permanent magnets 52 and a rotating shaft 60 .
　Rotor core 51 is arranged coaxially with stator core 21 . The shape of the rotor core 51 is generally annular (annular). A plurality of permanent magnets 52 are fixed to the rotor core 51 . In this embodiment, five pairs (10 pieces in total) of permanent magnets 52 are provided at intervals of 36° around the central axis O of the rotor core 51 . A rotating shaft 60 is arranged in the rotor core 51 . The rotating shaft 60 is fixed to the rotor core 51 .
　In this embodiment, a surface magnet type motor is used as the permanent magnet field type motor, but an embedded magnet type motor may be used.
[0067]
　Here, in order to form the core piece 40, for example, it is formed by punching an electromagnetic steel sheet, which is a rolled plate-shaped base material (hoop). The magnetic steel sheet is the magnetic steel sheet described in the section . The ratio of B50, W15/50, W15/100 (B50 ratio, W15/50 ratio, W15/ 100 ratio) are shown in Table 5. Each magnetic steel sheet has a thickness of 0.25 [mm]. As a known non-oriented electrical steel sheet, a non-oriented electrical steel sheet with W10/400 of 12.8 W/kg was used. W10/400 is the iron loss when the magnetic flux density is 1.0 T and the frequency is 400 Hz. In addition, the known non-oriented electrical steel sheet has excellent magnetic properties only in the rolling direction. In the following description, the magnetic steel sheets described in are also referred to as developed materials as necessary. In addition, known non-oriented electrical steel sheets are also referred to as conventional materials as needed.
[0068]
[Table 5]

[0069]
　Here, B50 is the magnetic flux density when excited with a magnetic field strength of 5000 [A/m], and W15/100 is the magnetic flux density when the magnetic flux density is 1.5 [T] and the frequency is 100 [Hz]. iron loss. Here, magnetic flux density and iron loss were measured by the method described in JIS C 2556:2015. In addition, in Table 5, the average value for each angle from the rolling direction of the developed material is normalized by setting the average value for each angle from the rolling direction of the conventional material to 1.000 (= the value for the developed material from the rolling direction (average value for each angle/average value for each angle from the rolling direction of the conventional material). Thus, the values ​​in Table 5 are relative values ​​(dimensionless quantities).
[0070]
　From Table 5, B50 of the developed material is 5.1 [%] larger than B50 of the conventional material. W15/50 of the developed material is 12.0% smaller than W15/50 of the conventional material. W15/100 of the developed material is 13.5% smaller than W15/100 of the conventional material. Thus, the developed material has a larger B50 and a smaller iron loss than the conventional material.
[0071]
　FIG. 4 is a graph showing an example of the relationship between the B50 ratio and the angle from the rolling direction. FIG. 5 is a graph showing an example of the relationship between the W15/50 ratio and the angle from the rolling direction. FIG. 6 is a graph showing an example of the relationship between the W15/100 ratio and the angle from the rolling direction.
　FIG. 7 is a diagram showing an example of 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 direction of easy magnetization as necessary. In FIG. 7, when the counterclockwise angle is a positive angle and the rolling direction RD is 0°, the directions of easy magnetization are ED1 and ED2. Theoretically, the magnetic properties of the four regions from the rolling direction RD to the direction in which the smaller angle from the rolling direction RD is 90° (the direction indicated by the broken line in FIG. 7) have a symmetrical relationship. have.
[0072]
　In addition, the B50 ratio, W15/50 ratio, and W15/100 ratio shown in FIGS. be. That is, the values ​​of the B50 ratio, W15/50 ratio, and W15/100 ratio shown in FIGS. 4, 5, and 6 are relative values ​​(dimensionless quantities).
　As shown in FIG. 4, in the developed material, the B50 ratio is the largest when the angle is 45° from the rolling direction, and the B50 ratio decreases as the angle approaches 0° and 90° from the rolling direction.
　On the other hand, in the conventional material, the B50 ratio is the smallest when the angle is 45° from the rolling direction.
[0073]
　As shown in FIGS. 5 and 6, the developed material has the largest W15/50 ratio and W15/100 ratio at an angle of 45° from the rolling direction, and approaches 0° and 90° from the rolling direction. The W15/50 ratio and the W15/100 ratio decrease as the value increases.
　On the other hand, in the conventional material, the W15/50 ratio and the W15/100 ratio become large when the angle from the rolling direction is 45° to 90°.
　As described above, the developed material has the best magnetic properties in the direction at an angle of 45° from the rolling direction (direction of easy magnetization ED1) and the direction at an angle of 135° from the rolling direction (direction of easy magnetization ED2). On the other hand, the magnetic properties are the worst in the direction with an angle of 0° from the rolling direction (rolling direction RD) and the direction with an angle of 90° from the rolling direction (direction perpendicular to the rolling direction RD).
[0074]
　The present inventors have improved the magnetic properties of the entire stator core by producing core pieces from a developed material that has better magnetic properties than conventional materials, and manufacturing a stator core equipped with a split core in which the produced core pieces are laminated. I came up with the idea that it can be done. In the developed material, the directions with excellent magnetic properties are the directions at angles of 45° and 135° from the rolling direction, and the directions with excellent magnetic properties are perpendicular to each other. On the other hand, in the core pieces as well, the radial direction of the teeth and the extending direction of the core back are perpendicular to each other. Therefore, the present inventors conceived that a core piece can be produced by matching the direction of excellent magnetic properties of the developed material with the radial direction of the teeth and the extending direction of the core back.
[0075]
　Based on such an idea, the core pieces are arranged so that the radial direction of the teeth is along the direction of an angle of 45° from the rolling direction of the developed material, and the extending direction of the core back is oriented at an angle of 135° from the rolling direction of the developed material. is configured to be along the direction of Alternatively, the core pieces are arranged such that the radial direction of the teeth is along the direction of an angle of 135° from the rolling direction of the developed material, and the extending direction of the core back is along the direction of an angle of 45° from the rolling direction of the developed material. configured to
[0076]

　Next, a method of manufacturing the stator core 21 including the step of forming the core pieces 40 from the developed material will be described. Manufacture of the stator core 21 mainly includes a core piece production process, a split core production process, and a stator core production process.
[0077]
[Core piece production step]
　In the core piece production step, the core piece 40 is produced by punching out the developed material using a mold.
　FIG. 8 is a diagram for explaining a die for punching the developed material. FIG. 8 is a schematic diagram (plan view) of the developed material 80 viewed from a direction orthogonal to the plate surface. Note that FIG. 8 shows the rolling direction RD and the directions (ED1, ED2) in which the magnetic properties are excellent, corresponding to the developed material 80. As shown in FIG.
　The developed material 80 is strip-shaped with its longitudinal direction in the rolling direction RD. The development material 80 is conveyed along the longitudinal direction by a conveying device. Therefore, in the example shown in FIG. 8, the rolling direction RD is the same as the direction of transport by the transport device. Pilot holes 81 are provided at intervals in the longitudinal direction at both ends of the developed material 80 in the width direction.
[0078]
　First, the conveying device inserts a pilot into the pilot hole 81 to convey the developed material 80 for a certain distance. Next, the pressing device punches out the transported developed material 80 using a mold having a punch and a die to produce the core piece 40 . Here, a plurality of core pieces 40 each having the same shape and size are produced by one punching by the pressing device.
[0079]
　The press machine punches the developed material 80 so that both the radial direction of the teeth of the core piece 40 and the extending direction of the core back are in the direction in which the developed material 80 has excellent magnetic properties. Specifically, as shown in FIG. 8, the die of the pressing device is arranged such that the radial direction of the teeth of the core piece 40 (one-dot chain line L1) is along the direction at an angle of 45° from the rolling direction of the developed material 80. It is set (along the direction of easy magnetization ED1). In addition, since the radial direction of the teeth and the extending direction of the core back of the core pieces 40 are perpendicular to each other, the radial direction of the teeth along the direction at an angle of 45° from the rolling direction of the developed material 80 allows the core back to extend. The extending direction is set along the direction at an angle of 135° from the rolling direction of the developed material 80 (along the direction of easy magnetization ED2).
[0080]
　Therefore, in the core piece 40 punched by the pressing machine, the radial direction of the teeth is along the direction at an angle of 45° from the rolling direction, and the extending direction of the core back is along the direction at an angle of 135° from the rolling direction. ing. In addition, in this embodiment, all the core pieces 40 punched out by the press machine are oriented in the same direction. Therefore, for all core pieces 40 to be punched, the radial direction of the teeth is along the direction at an angle of 45° from the rolling direction, and the extending direction of the core-back is along the direction at an angle of 135° from the rolling direction. .
[0081]
　In FIG. 8, the die for punching the core piece 40 is such that the radial direction of the teeth is along the direction of an angle of 45° from the rolling direction, and the extending direction of the core back is along the direction of an angle of 135° from the rolling direction. has been described, but it is not limited to this case.
　For example, like the core pieces 40A and 40B indicated by the two-dot chain line in FIG. 8, the radial direction of the teeth is along the direction at an angle of 135° from the rolling direction, and the extending direction of the core back is at an angle of 45° from the rolling direction. It may be a die that punches along the direction of . In this case, in the punched core pieces 40A and 40B, the tooth radial direction is along the direction at an angle of 135° from the rolling direction, and the core-back extending direction is at an angle of 45° from the rolling direction. along the
　Alternatively, a mold for punching the core piece 40 shown by the solid line in FIG. 8 so as to rotate 180° may be used, as in the case of the core piece 40C shown by the two-dot chain line in FIG. In this case, the punched core piece 40C, like the core piece 40 shown by the solid line in FIG. is along the direction at an angle of 135° from the rolling direction.
[0082]
　In addition, although FIG. 8 shows a die for punching four core pieces 40 in a straight line along the width direction of the developed material 80, it is not limited to this case, and five or more or three or less core pieces 40 are punched. A die may be used, or a die for punching in a zigzag pattern with respect to a straight line. Alternatively, a die may be used for punching out two or more of the core pieces 40, 40A to 40C facing in different directions shown in FIG. 8 at once.
[0083]
[Split Core Forming Process]
　In the split core forming process, the core pieces 40 are laminated to form the split cores 30 .
　Specifically, a plurality of core pieces 40 punched out by a pressing machine in the core piece producing step are aligned so that they are oriented in the same direction, and then connected and stacked such that the plate surfaces are in contact with each other. A plurality of core pieces 40 can be connected by adhering the plate surfaces of the core pieces 40 with an adhesive, crimping the core pieces 40 in the stacking direction, or by welding. The number of laminated core pieces 40 is changed according to the specifications or size of the stator core 21 to be manufactured. Moreover, when manufacturing the stator core 21 of this embodiment, 12 divided cores 30 are produced for one stator core 21 .
[0084]
　Here, in the core pieces 40, as described above, both the radial direction of the teeth and the extending direction of the core back are directions in which the magnetic properties of the developed material 80 are excellent, and in the split core 30, all the core pieces 40 They are aligned and stacked in the same direction. Therefore, the split core 30 in which the core pieces 40 are laminated can improve the magnetic properties of the tooth portions 31 and the core back portion 32 .
[0085]
[Stator Core Forming Process]
　In the stator core forming process, the split cores 30 are arranged and connected in the circumferential direction to form the stator core 21 . Specifically, the core back portions 32 of the plurality of split cores 30 produced in the split core producing step are arranged in an annular shape. At this time, the adjacent split cores 30 are positioned by fitting the convex portion 43a and the concave portion 43b of each core piece 40 to each other. In order to connect the split cores 30, the core back portions 32 of the adjacent split cores 30 can be connected by adhering with an adhesive or by welding.
　Further, when manufacturing the stator core 21 of the present embodiment, 12 split cores 30 are arranged in the circumferential direction and connected.
　The stator core 21 can be manufactured through the steps described above. Note that when manufacturing the stator 20 or the rotating electric machine 10 using the manufactured stator core 21, a known manufacturing method can be used.
[0086]

　Next, magnetic properties were compared between split cores using core pieces produced from the developed material and split cores using core pieces produced from the conventional material.
　First, core pieces produced by punching out the developed material were stacked to produce split core samples. The split core using the core piece of the developed material in this way is called the split core of the invention example. In addition, core pieces obtained by punching the developed material are referred to as core pieces of invention examples. The split cores of the invention examples were produced by the method described in the above section . In the core piece of the invention example, the radial direction of the teeth is along the direction of an angle of 45° from the rolling direction of the developed material, and the extending direction of the core back is a direction of an angle of 135° from the rolling direction of the developed material. along the
　On the other hand, a split core sample was produced by laminating core pieces produced by punching a conventional material. A split core using conventional core pieces is referred to as a comparative split core. A core piece obtained by punching a conventional material is referred to as a core piece of a comparative example. The split cores of the comparative example were produced by the method described in the above section . In the core piece of the comparative example, the radial direction of the teeth is along the direction of an angle of 0° from the rolling direction of the conventional material, and the extending direction of the core back is a direction of an angle of 90° from the rolling direction of the conventional material. along the
[0087]
　Further, the split cores of the invention examples and the split cores of the comparative example have the following specifications.
　Stator core outer diameter: 77.0 [mm], stator core inner diameter: 40.0 [mm], stator core height (laminated thickness): 45.0 [mm], core piece (electromagnetic steel sheet) thickness: 0.0 mm. 25 [mm], number of poles: 10, number of slots: 12
　Here, as a comparison of magnetic properties between the split core of the invention example and the split core of the comparative example, B50, that is, the magnetic field strength is 5000 [A/m]. Table 6 shows the ratio of the magnetic flux density when excited at .
[0088]
[Table 6]

[0089]
　As shown in Table 6, when the magnetic flux density of the split core of Comparative Example was 1.000, the magnetic flux density of the split core of Inventive Example was 1.042. From Table 6, B50 of the split core of the invention example is larger than B50 of the split core of the comparative example by 4.2 [%]. Thus, it was confirmed that the split core using the core pieces produced from the developed material has a higher magnetic flux density and improved magnetic properties than the split core using the core pieces produced from the conventional material. .
[0090]
　In this way, by arranging the split cores of the invention example having a large magnetic flux density in the circumferential direction to manufacture a stator core (referred to as the stator core of the invention example), a stator core (referred to as the stator core of the invention example) is manufactured by arranging the split cores of the comparative example in the circumferential direction. The magnetic flux density can be increased in the entire stator core, and the magnetic properties can be improved, compared to the stator core of the comparative example.
　Further, by applying the stator core of the example of the invention having a large magnetic flux density to the rotating electric machine, the torque can be improved more than that of the rotating electric machine to which the stator core of the comparative example is applied. Further, when the rotating electric machine to which the stator core of the invention example is applied outputs the same torque as the rotating electric machine to which the stator core of the comparative example is applied, the current flowing through the winding wound around the stator core of the invention example can be reduced. copper loss can be reduced.
[0091]
　As described above, according to the present embodiment, the magnetic properties of the entire stator core including the split cores can be improved by using the developed electromagnetic steel sheets with excellent magnetic properties for the core pieces that constitute the split cores. can. Further, according to the present embodiment, for each core piece of all the split cores included in the stator core, both the radial direction of the teeth and the extending direction of the core back are the directions in which the magnetic steel sheet of the developed material has excellent magnetic properties. , the magnetic properties of the entire stator core can be further improved. In addition, since the magnetic characteristics are improved, 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, so the slot area can be expanded and the winding space factor improved. can be made
　In this embodiment, the superiority of the developed material compared to the case where the conventional material is a non-oriented electrical steel sheet was explained, but the developed material also has superiority compared to the case where the conventional material is a bidirectional electrical steel sheet. is doing. Specifically, the developed material can reduce the manufacturing cost compared to the case where the conventional material is a bi-oriented electrical steel sheet. In addition, since the grain size of the steel sheet structure of the developed material is smaller than that of the conventional material, which is a bi-oriented electrical steel sheet, the iron loss is reduced under high-frequency conditions when core pieces are laminated to form a split core. can be suppressed.
[0092]

　In the present embodiment described above, for each core piece of all the split cores provided in the stator core, both the radial direction of the teeth and the extending direction of the core back are excellent in the magnetic properties of the magnetic steel sheet of the developed material. Although the case has been described in which the direction is along the direction, the present invention is not limited to this case.
　In this modification, for each core piece of at least one split core among the plurality of split cores provided in the stator core, both the radial direction of the teeth and the extending direction of the core-back have the magnetic properties of the developed electromagnetic steel sheet. A case will be described where it is sufficient if the direction is along the superior direction. In other words, the stator core of this modification is a segmented core composed of core pieces in which both the radial direction of the teeth and the extending direction of the core back are along the direction in which the magnetic steel sheet of the developed material has excellent magnetic properties. and split cores composed of core pieces in which the radial direction of the teeth or the direction in which the core back extends is not aligned with the direction in which the magnetic steel sheet of the developed material has excellent magnetic properties. A stator core in which different types of split cores are mixed in this manner has portions with good magnetic properties and portions with poor magnetic properties, and the distribution of the magnetic properties of the stator core varies, resulting in an increase in iron loss.
[0093]
　In this modified example, when split cores of different types are mixed, the width of the tooth portion whose radial direction is along the direction with excellent magnetic properties is changed to the width of the tooth portion whose radial direction is not along the direction with excellent magnetic properties. The stator core is configured to be narrower than it is wide. Furthermore, in this modification, when split cores of different types are mixed, the product of the width of the teeth of the split cores and the magnetic flux density of the teeth when excited with a predetermined magnetic field strength is The stator core is configured so that each tooth portion of the split core is substantially constant. By configuring the stator core in this way, it is possible to reduce variations in magnetic flux density and suppress iron loss even in a stator core in which split cores of different types are mixed.
[0094]
　FIG. 9 is a diagram for explaining the width of the teeth. (a) of FIG. 9 is an example of tooth portions 31A that are parallel along the radial direction. In this example, the tooth portion 31A itself is parallel along the radial direction. (b) of FIG. 9 is an example of a teeth portion 31B having parallel slots along the radial direction. In this example, the slots located between the circumferentially adjacent tooth portions 31B are parallel in the radial direction.
　Here, the width of the tooth portion is the circumferential length of the stator core at the central position of the tooth linear region. The tooth linear region is the region of the longest straight line among the straight lines that constitute the ends of the teeth in the circumferential direction of the stator core in the cross section of the stator core when cut in the direction perpendicular to the axis of the stator core. It is obtained for each of the two ends of the teeth in.
[0095]
　In the example shown in FIG. 9A, a straight line connecting positions 311 and 312 and a straight line connecting positions 313 and 314 are tooth linear regions. In addition, in the example shown in FIG. 9A, the central positions of the tooth linear regions are positions 321 and 322 . Therefore, the width of the teeth portion 31A shown in FIG. 9A is the distance TW between the positions 321 and 322. As shown in FIG.
　In the example shown in FIG. 9B, the straight line connecting the positions 315 and 316 and the straight line connecting the positions 317 and 318 are the teeth linear regions. Also, in the example shown in FIG. 9B, the central positions of the tooth linear regions are positions 323 and 324 . Therefore, the width of the tooth portion 31B shown in FIG. 9B is the distance TW between the positions 323 and 324. As shown in FIG.
[0096]
　FIG. 9A shows an example of tooth portions 31A parallel to each other along the radial direction, so that the width of the tooth portions 31A is constant regardless of where in the tooth linear region in the radial direction.
　On the other hand, in (b) of FIG. 9, since the slot is an example of the tooth portion 31B parallel to the radial direction, the actual width of the tooth portion 31B varies depending on where in the tooth linear region in the radial direction. Because of the difference, the width of the tooth portion 31B is set to the distance TW between the positions 323 and 324 described above as a representative value.
[0097]
　In the above-described embodiment, by the method described in the section, it is possible to produce split cores in which the radial direction of the tooth portion is along the direction of excellent magnetic properties.
　Next, an example of producing a split core in which the radial direction of the tooth portion is not aligned with the direction in which the magnetic properties are excellent will be described. In addition, the description of the same contents as the method described in the section will be omitted as appropriate.
[0098]
　First, in the core piece producing step, the core piece 90 is produced by punching out the developed material using a mold.
　FIG. 10 is a diagram for explaining a die for punching the developed material. The developed material 80 shown in FIG. 10 is the same electromagnetic steel sheet as the developed material 80 shown in FIG. FIG. 10 shows the rolling direction RD and the directions (ED1, ED2) in which the magnetic properties are excellent, corresponding to the developed material 80. As shown in FIG.
[0099]
　The pressing machine punches the developed material 80 so that neither the radial direction of the teeth of the core piece 90 nor the extending direction of the core back is in the direction in which the developed material 80 has excellent magnetic properties. Specifically, as shown in FIG. 10, the die of the pressing device is arranged such that the radial direction of the teeth of the core piece 90 (one-dot chain line L1) is along the direction of 0° from the rolling direction of the developed material 80. set. In addition, since the radial direction of the teeth and the extending direction of the core back of the core piece 90 are perpendicular to each other, the radial direction of the teeth is along the direction of 0° from the rolling direction of the developed material 80, so that the core back is formed. The extending direction is set along the direction at an angle of 90° from the rolling direction of the developed material 80 .
[0100]
　Therefore, in the core piece 90 punched by the pressing machine, the radial direction of the teeth is along the direction at an angle of 0° from the rolling direction, and the extending direction of the core back is along the direction at an angle of 90° from the rolling direction. ing. In this modified example, all the core pieces 90 punched out by the pressing device have the same tooth radial direction. Therefore, for all the punched core pieces 90, the radial direction of the teeth is along the direction at an angle of 0° from the rolling direction, and the extending direction of the core-back is along the direction at an angle of 90° from the rolling direction. .
　Next, by aligning the plurality of punched core pieces 90 in the same direction and connecting and laminating them so that the plate surfaces are in contact with each other, the radial direction of the tooth portion is the direction in which the magnetic properties are excellent. It is possible to generate split cores that are not aligned.
[0101]
　Here, the core piece 90 shown in FIG. 10 and the core piece 40 shown in FIG. 8 are set so that the tooth width is different from each other. Specifically, the width of the teeth of the core piece 90 shown in FIG. 10 is set to be wider than the width of the teeth of the core piece 40 shown in FIG. In other words, the width of the teeth of core piece 40 shown in FIG. 8 is set to be narrower than the width of the teeth of core piece 90 shown in FIG.
　By configuring the stator core by mixing the split core in which the core pieces 90 shown in FIG. 10 are laminated and the split core in which the core pieces 40 are laminated shown in FIG. The width of the tooth portion along the radial direction can be configured to be narrower than the width of the tooth portion not along the direction in which the magnetic properties are excellent. By configuring the stator core in this way, it is possible to reduce variations in the magnetic flux density within the stator core.
[0102]
　In addition, in this modification, when split cores of different types coexist, the product of the width of the teeth of the split cores and the magnetic flux density of the teeth when excited with a predetermined magnetic field strength is The stator core is configured so that each tooth portion of the split core is substantially constant.
　An example of determining the width of the tooth portion so that the product of the width of the tooth portion and the magnetic flux density of the tooth portion is substantially constant for each tooth portion of all split cores will be described below.
[0103]
　First, in a rotating electric machine to which the stator core is to be applied, when the width of all the teeth is constant, the average magnetic flux density of the teeth is analyzed when it is operated under predetermined operating conditions (for example, predetermined torque). do. The average magnetic flux density of the tooth portion is a value obtained by averaging the maximum values ​​of the magnetic flux density at each location in each tooth portion. The average magnetic flux density can be derived by performing an electromagnetic field analysis (numerical analysis) based on Maxwell's equations, or by actually measuring the induced voltage using a search coil in the manufactured stator core and integrating the induced voltage.
[0104]
　Next, the average magnetic field strength H [A/m] of the tooth portion is calculated from the average magnetic flux density of the tooth portion. The average magnetic field intensity of the teeth can be calculated based on the relative permeability of the developed material. Next, based on the material properties of the developed material A, the magnetic flux density B[T] of the teeth for each angle from the rolling direction when the teeth are excited with the average magnetic field strength is calculated. The magnetic flux density of the teeth at each angle from the rolling direction can be derived from the BH characteristics of the developed material at each angle from the rolling direction.
　In this modified example, in the split core in which the core pieces 40 are laminated as shown in FIG. 8, the magnetic flux density of the tooth portion at an angle of 45° from the rolling direction is calculated. In addition, in the split core in which the core pieces 90 are laminated as shown in FIG. 10, the magnetic flux density of the tooth portion at an angle of 0° from the rolling direction is calculated. As described above, the developed material has the largest B50 ratio when the angle is 45° from the rolling direction, and the B50 ratio decreases as the angle approaches 0° and 90° from the rolling direction. Therefore, the magnetic flux density of the teeth at an angle of 45° from the rolling direction is calculated to be large, and the magnetic flux density of the teeth at an angle of 0° from the rolling direction is calculated to be small.
[0105]
　Next, the optimum tooth width is determined for each angle from the rolling direction. Specifically, based on the calculated magnetic flux density of the tooth portion for each angle from the rolling direction, the tooth portion is adjusted so that the product of the width of the tooth portion and the magnetic flux density of the tooth portion is substantially constant at each tooth portion. Determines the width of the
　Therefore, the width of the tooth portion is calculated to be narrow in the split core in which the core pieces 40 are stacked as shown in FIG. 8, and the width of the tooth portion is calculated to be wide in the split core in which the core pieces 90 are stacked as shown in FIG.
[0106]
　A mold for punching the core pieces 40 shown in FIG. 8 and a mold for punching the core pieces 90 shown in FIG. The developed material is punched out for each designed mold to produce core pieces 40 and core pieces 90, respectively.
　By configuring the stator core by mixing the split core in which the core pieces 40 shown in FIG. 8 are laminated and the split core in which the core pieces 90 are laminated shown in FIG. The stator core can be configured such that the product of the magnetic flux density of the tooth portion when excited with the magnetic field strength of 1 is approximately constant for each tooth portion of all the split cores.
[0107]
　As described above, in this modification, when different types of split cores are mixed, the product of the width of the teeth of the split core and the magnetic flux density of the teeth when excited with a predetermined magnetic field strength is The stator core is configured so that each tooth portion of all split cores is substantially constant. Therefore, even in a stator core in which split cores of different types are mixed, variations in magnetic flux density can be reduced, and iron loss can be suppressed. Note that the term "substantially constant" is not limited to being completely constant, but includes the range in which the iron loss can be suppressed more than in the comparative example. Specifically, "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 a range of ±5%. For example, when 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 is 1.425 [T]. It is within the range of 1.575 [T] (within the range of ±5%).
[0108]
　In this modified example, the case of analyzing the average magnetic flux density of the teeth when operated under predetermined operating conditions (for example, predetermined torque) has been described, but the predetermined operating conditions can be selected as appropriate. . For example, among a plurality of possible operating conditions, the operating condition with the highest operating time ratio may be set as the predetermined operating condition. Further, the determined optimal tooth width may be weighted based on the ratio of operating times for each of a plurality of operating conditions.
　Also, in this modification, a stator core in which two types of split cores are mixed has been described, but the present invention is not limited to this case, and can also be applied to a stator core in which three or more types of split cores are mixed.
[0109]
　Although the present invention has been described with various embodiments, the present invention is not limited to these embodiments, and modifications and the like are possible within the scope of the present invention.
Industrial applicability
[0110]
　ADVANTAGE OF THE INVENTION According to this invention, the magnetic characteristic of the stator core provided with several split cores can be improved. Therefore, industrial applicability is high.
Code explanation
[0111]
　10: Rotary electric machine
　21: Stator core
　30: Split core
　31: Teeth part
　32: Core back part
　40: Core piece
　41: Teeth
　42: Core back
　50: Rotor
　51: Rotor core
　52: Permanent magnet
　60: Rotating shaft

The scope of the claims

[Claim 1]
　A stator core having a plurality of split cores,
　wherein the plurality of split cores are configured by laminating core pieces made of an electromagnetic steel sheet, and the
　electromagnetic steel sheet 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, and Au : 2.50% to 5.00% in total,
　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: 0.0000% to 0.0100% in total,
　Mn content (mass %) is [Mn], Ni content (mass%) is [Ni], Co content (mass%) is [Co], Pt content (mass%) is [Pt], Pb content (mass%) [Pb], Cu content (mass%) [Cu], Au content (mass%) [Au], Si content (mass%) [Si], sol. The Al content (% by mass) is measured as [sol. Al], it has a chemical composition that satisfies the following formula (1) and the
　balance is Fe and impurities,
　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 When the value is B50D2, the following formulas (2) and (3) are satisfied, the X-ray random intensity ratio of {100} <011> is 5 or more and less than 30, and the plate thickness is 0.50 mm or less
　At least one of the plurality of split cores has a core piece along which both the radial direction of the teeth
　and the extending direction of the core back are along the direction in which the magnetic steel sheet has excellent magnetic properties. A stator core characterized by:
　([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])−([Si]+[sol.Al])>0% (1)
　(B50D1+B50D2)/2>1.7T (2)
　(B50D1+B50D2)/2>(B50L+B50C)/2 (3)
[Claim 2]
　2. The stator core according to claim 1, wherein the stator core satisfies the following formula (4).
　(B50D1+B50D2)/2>1.1×(B50L+B50C)/2 (4)
[Claim 3]
　2. The stator core according to claim 1, wherein the following formula (5) is satisfied.
　(B50D1+B50D2)/2>1.2×(B50L+B50C)/2 (5)
[Claim 4]
　2. The stator core according to claim 1, wherein the stator core satisfies the following formula (6).
　(B50D1+B50D2)/2>1.8T (6)
[Claim 5]
　In the magnetic steel sheet,
　the directions in which the magnetic properties are excellent are the directions at angles of 45° and 135° from the rolling direction of the magnetic steel sheet, and
　the radial directions of the teeth are at angles of 45° and 135° from the rolling direction. and
　the extending direction of the core-back is along either one of the angles 45° and 135° from the rolling direction. 2. The stator core according to 1.
[Claim 6]
　In the plurality of split cores, in
　all the core pieces of the split cores, both the radial direction of the teeth and the extending direction of the core back are along the direction in which the magnetic steel sheet has excellent magnetic properties. 6. The stator core according to any one of claims 1 to 5.
[Claim 7]
　The plurality of split cores each have
　a tooth portion, and among the plurality of tooth portions, the width of the tooth portion along the direction in which the magnetic properties are excellent is the width of the tooth portion not along the direction in which the magnetic properties are excellent. 6. The stator core according to any one of claims 1 to 5, wherein the stator core is narrower than.
[Claim 8]
　8. The product of the width of the tooth portion and the magnetic flux density of the tooth portion when excited with a predetermined magnetic field strength is substantially constant for each tooth portion of the plurality of split cores. The stator core described in .
[Claim 9]
　A rotating electric machine comprising the stator core according to claim 1 .