JP6981153B2 - Stator core design index determination method, stator core design index determination device, and stator core manufacturing method - Google Patents

Description

The present invention relates to a method for determining a design index of a stator core, a device for determining a design index of a stator core, and a method for manufacturing a stator core, and is particularly suitable for use in designing a stator core.

A rotary electric machine such as an electric motor (motor) or a generator (generator) has a rotor and a stator. It is desirable that the rotary electric machine is small in order to save space, and it is necessary to design the rotary electric machine so that it can meet the demand for miniaturization. For example, in response to the demand for miniaturization of a motor, there is a design method for suppressing a decrease in the output of the motor by increasing the rotation speed of the motor (rotor). When the motor is miniaturized, the torque of the motor decreases as the diameter of the rotor becomes smaller, but the output of the motor is proportional to the product of the torque and the number of revolutions. Output reduction can be suppressed. In that case, it may be required to drive the motor at a frequency higher than the commercial frequency, for example, 400 [Hz] to several [kHz]. In such a case, the frequency of the magnetic flux density generated inside the stator core constituting the stator becomes high, so that the iron loss of the stator core increases.

Therefore, there is a technique described in Patent Documents 1 to 3 as a technique for suppressing iron loss of the stator core.
Patent Document 1 describes that a split core is used as the stator core. Specifically, Patent Document 1 describes that the split core is configured so that the rolling direction of the electrical steel sheet faces the longitudinal direction of the teeth (the radial direction of the motor). Further, Patent Document 1 describes that the divided core is configured so that the sum of _{W 10/400} (L) and W _{10/400 (C-50MPa) is 55 [W / kg] or less.} There is. Here, W _10/400 (L) is the iron loss in the rolling direction of the electrical steel sheet when the maximum magnetic flux density is 1 [T] and the excitation frequency is 400 [Hz]. W _10/400 (C-50MPa) is in a state where a compressive stress of 50 [MPa] is applied in the direction perpendicular to the rolling direction, the maximum magnetic flux density is 1 [T], and the excitation frequency is 400 [Hz]. ] Is the iron loss in the rolling direction of the electrical steel sheet.

In Patent Document 2, W _15/50 (C) / W _15/50 (L) is 1.35 or more and 2.00 or less, and W _15/50 (L + C) is 2.3 [W / kg] or less. It is described that the non-oriented electrical steel sheet is applied to the stator core. Here, W _15/50 (C) is the iron loss in the direction perpendicular to the rolling direction of the electrical steel sheet when the maximum magnetic flux density is 1.5 [T] and the excitation frequency is 50 [Hz]. , W _15/50 (L) is the iron loss in the rolling direction of the electrical steel sheet when the maximum magnetic flux density is 1.5 [T] and the excitation frequency is 50 [Hz]. W _15/50 (L + C) has an iron loss in the direction perpendicular to the rolling direction of the electromagnetic steel plate when the maximum magnetic flux density is 1.5 [T] and the excitation frequency is 50 [Hz], and the maximum magnetic flux density. Is 1.5 [T] and the average value with the iron loss in the rolling direction of the electromagnetic steel plate when the excitation frequency is 50 [Hz] (= {W _15/50 (C) + W _15/50 (L)). } ÷ 2).

Patent Document 3 also describes that a split core is used as the stator core, as in Patent Document 1. Specifically, in Patent Document 3, B ₁₀ (L) is 1.7 [T] or more, and B ₁₀ (C) / B ₁₀ (L) is 0.75 or more and 1.0 or less. It is described that the electrical steel sheet is applied to the split core. Here, B ₁₀ (L) is the magnetic flux density in the rolling direction of the electrical steel sheet at 1000 [A / m]. B ₁₀ (C) is the magnetic flux density in the direction perpendicular to the rolling direction of the electrical steel sheet at 1000 [A / m]. Further, Patent Document 3 describes that the divided core is configured so that the ratio (= Y / Th) of the width Y of the core back portion to the width Th of the teeth portion is 0.5 or more and 1.0 or less. ing.

Japanese Unexamined Patent Publication No. 2011-26682 Japanese Unexamined Patent Publication No. 8-41603 Japanese Unexamined Patent Publication No. 2004-999998

However, in the techniques described in Patent Documents 1 and 2, only the magnetic characteristics of the electromagnetic steel sheets constituting the stator core are examined, and the shape of the stator core is not considered. Therefore, from the viewpoint of the shape of the stator core, the iron loss of the stator core cannot be reduced.
Further, in the technique described in Patent Document 3, the ratio of the width Y of the core back portion to the width Th of the teeth portion is taken into consideration, but only under the condition that this ratio is 0.5 or more and 1.0 or less. The iron loss of the stator core cannot be evaluated correctly (this point will be described later with reference to FIG. 8A).

The present invention has been made in view of the above problems, and makes it possible to design a stator core by using an index capable of evaluating iron loss of the stator core as an index regarding the shape of the stator core. The purpose is.

Design index determination method of the stator core of the present invention, a yoke, and a plurality of teeth, a stator core design index determination method configured by stacking soft magnetic plate, for candidates of the shape of the stator core The shape of the stator core is based on the shape parameter acquisition step of acquiring information including the circumferential area, the radial area, the yoke width, and the tooth width as the shape parameters, and the shape parameters for one candidate of the shape of the stator core. The design of the stator core is based on the shape index deriving process for deriving the shape index, which is an index related to the shape index, and the shape index satisfying a predetermined condition based on the shape index based on the shape index derived by the shape index deriving step. It has a shape index determination step of determining as an index, and the smaller angle between the L direction, which is the rolling direction of the soft magnetic plate, and the longitudinal direction of the teeth is the soft magnetic plate. The yoke width is smaller than the smaller of the angles formed by the C direction, which is the direction perpendicular to the rolling direction of the tooth, and the longitudinal direction of the teeth, and the yoke width is at the center position of the slot in the circumferential direction of the stator core. It is a value obtained by subtracting the inner diameter from the outer diameter of the stator core, the teeth width is the circumferential length of the teeth at the center position of the teeth straight line region, and the teeth straight line region is on the axis of the stator core. In the cross section when the stator core is cut in the vertical direction, the region of the longest straight line among the straight lines constituting the ends of the teeth in the circumferential direction of the stator core is defined as the two ends of the teeth in the circumferential direction of the stator core. The radial area is the sum of the area of the yoke portion region and the area of the teeth portion region, and the yoke portion region is the first point and the second point. And a third point are regions surrounded by a triangle whose apex is, and the first point is a cross section of the stator core when the stator core is cut in a direction perpendicular to the axis of the stator core. The intersection of the virtual line passing through the center position of the tooth in the circumferential direction, the axis of the stator core, and the outer peripheral surface of the stator core, and the second point and the third point are the stator core. In the cross section when the stator core is cut in a direction perpendicular to the axis of, the point on the respective region of the two straight line regions of the teeth in one of the teeth is the position closest to the outer peripheral surface of the stator core. And before The area of the tooth portion is the area of the cross section when the stator core is cut in the direction perpendicular to the axis of the stator core, and the area of the stator core is larger than the virtual line connecting the second point and the third point to each other. It is a region on the axis side, and the circumferential area is a value obtained by subtracting the radial area from the area of the cross-sectional area when the stator core is cut in the direction perpendicular to the axis of the stator core. do.
Further, the method for determining the design index of the stator core of the present invention includes a design process for designing a stator core having a shape determined by the shape parameter used when deriving the shape index determined by the shape index determining step. May be good.

The stator core of the design index determining apparatus of the present invention includes a yoke and a plurality of teeth, a design index determining apparatus of the stator core formed by stacking soft magnetic plate, for candidates of the shape of the stator core The shape of the stator core is based on the shape parameter acquisition means for acquiring information including the circumferential area, the radial area, the yoke width, and the tooth width as the shape parameters, and the shape parameters for one candidate of the shape of the stator core. The design of the stator core is based on the shape index deriving means for deriving the shape index which is an index related to the shape index and the shape index which satisfies a predetermined condition based on the shape index based on the shape index derived by the shape index deriving means. It has a shape index determining means for determining as an index, and the smaller angle between the L direction, which is the rolling direction of the soft magnetic plate, and the longitudinal direction of the teeth is the soft magnetic plate. The yoke width is smaller than the smaller of the angles formed by the C direction, which is the direction perpendicular to the rolling direction of the tooth, and the longitudinal direction of the teeth, and the yoke width is at the center position of the slot in the circumferential direction of the stator core. It is a value obtained by subtracting the inner diameter from the outer diameter of the stator core, the teeth width is the circumferential length of the teeth at the center position of the teeth straight line region, and the teeth straight line region is on the axis of the stator core. In the cross section when the stator core is cut in the vertical direction, the region of the longest straight line among the straight lines constituting the ends of the teeth in the circumferential direction of the stator core is defined as the two ends of the teeth in the circumferential direction of the stator core. The radial area is the sum of the area of the yoke portion region and the area of the teeth portion region, and the yoke portion region is the first point and the second point. And a third point are regions surrounded by a triangle whose apex is, and the first point is a cross section of the stator core when the stator core is cut in a direction perpendicular to the axis of the stator core. The intersection of the virtual line passing through the center position of the tooth in the circumferential direction, the axis of the stator core, and the outer peripheral surface of the stator core, and the second point and the third point are the stator core. In the cross section when the stator core is cut in a direction perpendicular to the axis of, the point on the respective region of the two straight line regions of the teeth in one of the teeth is the position closest to the outer peripheral surface of the stator core. And before The area of the tooth portion is the area of the cross section when the stator core is cut in the direction perpendicular to the axis of the stator core, and the area of the stator core is larger than the virtual line connecting the second point and the third point to each other. It is a region on the axis side, and the circumferential area is a value obtained by subtracting the radial area from the area of the cross-sectional area when the stator core is cut in the direction perpendicular to the axis of the stator core. do.

The method for manufacturing a stator core of the present invention includes each step of the method for determining a design index of the stator core and a step of manufacturing the stator core designed in the design step, and each step of the method for designing the stator core. When, characterized in that it and a step of manufacturing a stator core having a shape determined by the shape determination step.

According to the present invention, the stator core can be designed using an index capable of evaluating the iron loss of the stator core as an index regarding the shape of the stator core.

FIG. 1 is a diagram showing a first example of a functional configuration of a stator core design device. FIG. 2 is a flowchart illustrating a first example of the stator core design method. FIG. 3 is a diagram illustrating an example of a method of collecting an electromagnetic steel sheet constituting a divided core and an example of a method of collecting an electromagnetic steel sheet constituting a bent core. FIG. 4 is a diagram illustrating an example of a tooth width and a yoke width. FIG. 5 is a diagram illustrating an example of a radial area and a circumferential area. FIG. 6 is a diagram showing an example of the shape of the split core. FIG. 7 is a diagram showing an example of a shape parameter and a shape index. FIG. 8 is a diagram showing an example of the relationship between the tooth width / yoke width and the iron loss of the stator core, and an example of the relationship between the radial area / circumferential area and the iron loss of the stator core. FIG. 9 is a diagram showing an example of the relationship between the shape index and the iron loss of the stator core. FIG. 10 is a diagram showing a second example of the functional configuration of the stator core design device. FIG. 11 is a flowchart illustrating a second example of the stator core design method. FIG. 12 is a diagram showing an example of material parameters. FIG. 13 is a diagram showing an example of the relationship between the average iron loss in the LC direction and the iron loss of the stator core. FIG. 14 is a diagram showing an example of the relationship between the LC ratio and the iron loss of the stator core. FIG. 15 is a diagram showing an example of the relationship between the material index and the iron loss of the stator core.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First Embodiment)
FIG. 1 is a diagram showing an example of a functional configuration of the stator core design device 100. FIG. 2 is a flowchart illustrating an example of a stator core design method using the stator core design device 100. The hardware of the stator core design device 100 is realized by using, for example, an information processing device having a CPU, ROM, RAM, HDD, and various hardware, or dedicated hardware.

In the present embodiment, a case where a stator core composed of stacked soft magnetic material plates (plate-shaped soft magnetic material) is designed by using a split core or a bent core is given as an example. explain. Further, in the present embodiment, a case where an electromagnetic steel sheet (at least one of a non-oriented electrical steel sheet and a grain-oriented electrical steel sheet) is used as the soft magnetic material plate will be described as an example.

FIG. 3 is a diagram illustrating an example of a method of collecting electrical steel sheets constituting a split core (FIG. 3 (a)) and an example of a method of collecting electrical steel sheets constituting a bent core (FIG. 3 (b)). Is.
The split core is a core that becomes part of the stator core. The split core has a region 310 that constitutes the teeth of the stator core and a region 320 that constitutes the yoke. The end of the region 320 constituting the yoke of the stator core, the positions of the ends 321 and 322 in the circumferential direction of the stator core pass through the center of the slot in the circumferential direction of the stator core, and the virtual line and the yoke extending in the radial direction of the stator core. It becomes the position where and meet. As described above, the divided core is each part when the stator core is divided into a plurality of parts in the circumferential direction of the stator core, with the position of the center of the slot in the circumferential direction of the stator core as the divided position.

As shown in FIG. 3A, the electrical steel sheet 330 is punched according to the planar shape of the split core, and a plurality of electrical steel sheets are stacked so that the adjacent plate surfaces of the punched electrical steel sheets meet each other. This forms a split core. At this time, the longitudinal direction of the region 310 constituting the teeth of the stator core faces the rolling direction of the electrical steel sheet 330, and the longitudinal direction of the region 320 constituting the yoke of the stator core is a plate perpendicular to the rolling direction of the electrical steel sheet 330. Turn to face direction. In the following description, the rolling direction of the electromagnetic steel sheet is referred to as the L direction as necessary, and the plate surface direction perpendicular to the rolling direction of the electromagnetic steel sheet is referred to as the C direction as necessary. A stator core is configured by abutting the ends 321 and 322 of the split cores and combining a plurality of split cores. If necessary, processing for fixing the electromagnetic steel sheet constituting the divided core, such as welding or caulking, is performed. Further, the plurality of divided cores are fixed to the case by shrink fitting or the like.

As shown in FIG. 3A, it is more electromagnetic when the electrical steel sheet 330 is punched according to the planar shape of the split core than when the electrical steel sheet 330 is punched according to the planar shape of the entire stator core. In the steel plate 330, the portion not used as the stator core is reduced. Further, the winding method of the coil can be made more efficient when the coil is arranged with respect to the portion constituting the tooth of the divided core than when the coil is arranged with respect to the teeth of the integrated stator core. Therefore, the copper loss of the rotary electric machine can be reduced.

It is most preferable that the longitudinal direction of the region constituting the teeth of the stator core completely coincides with the L direction of the electrical steel sheet 330, but it is necessary to take accuracy of punching and design tolerance. , It is not always easy to do this. Therefore, the longitudinal direction of the region constituting the teeth of the stator core may be set to substantially coincide with the L direction of the electrical steel sheet 330. Further, in FIG. 3A, a case where one tooth is included in one divided core is shown as an example. For example, when two teeth are included in one divided core, the teeth of the stator core are used. It is difficult to substantially match the longitudinal direction of the constituent regions with the L direction of the electrical steel sheet 330. In such a case, the smaller angle between the longitudinal direction and the L direction of the region constituting the teeth of the stator core is the angle formed by the longitudinal direction and the C direction of the region constituting the teeth of the stator core. It suffices if it is smaller than the smaller angle.

The bent core has a first cut surface extending from the inner peripheral surface of the stator core (yoke) to the outer peripheral surface of the stator core (yoke) along the radial direction of the stator core at one position in the center of the slot in the circumferential direction of the stator core. Have. The inner peripheral surface of the stator core is the inner peripheral surface of the stator core among the two surfaces surrounding the shaft of the stator core, and the outer peripheral surface of the stator core is the outer peripheral surface of the stator core among the two surfaces surrounding the shaft of the stator core. The side surface. Further, in FIG. 3B, the first cut surface is formed by abutting the ends 341 and 342.

Further, the bent core is a stator core from the inner peripheral surface of the stator core (yoke) toward the outer peripheral surface of the stator core (yoke) along the radial direction of the stator core at other points in the center of the slot in the circumferential direction of the stator core. It has a second cut surface that does not reach the outer peripheral surface of the (yoke). In FIG. 3B, the second cut surface is formed by abutting the two sides constituting the regions 343a to 343k.
The gap between the first cut surface and the second cut surface is preferably narrow, and most preferably 0 (zero).

When the parts of the electrical steel sheets constituting the folded core are arranged in a row, the electrical steel sheets each have a region constituting the teeth (for example, region 344) and a region constituting the yoke (for example, region). 345) and a plurality of core portions 346a to 346l having the above are arranged in a row in a state of being connected to each other. The plurality of core portions 346a to 346l have the same shape and size except for the two core portions 346a to 346l at both ends.
The two adjacent core portions (eg, core portions 346a, 346b) are the positions of the longitudinal ends of the regions constituting the yoke and correspond to the outer peripheral surface of the stator core (eg, position 347). Is connected by. On the side corresponding to the inner peripheral side of the stator core than the connected portion, the notch becomes narrower as it approaches the position corresponding to the outer peripheral surface of the stator core, and the planar shape is, for example, a triangular notch (a notch having a triangular shape). Regions 343a to 343k) are formed.

Further, of the plurality of core portions 346a to 346l, the two core portions 346a and 346l at both ends are connected to the other core portion only on one side and not on the other side. As described above, of the longitudinal ends of the regions constituting the yokes of the two core portions 346a and 346l at both ends, the ends 341 and 342 on the side not connected to the other core portions are abutted against each other. 1 constitutes the cut surface. The two core portions 346a and 346l at both ends have only the shapes of the end portions 341 and 342 on the side of the longitudinal end portions of the region constituting the yoke that are not connected to the other core portions, and the other core portions 346b to 346k. Unlike the other core portions 346b to 346k, the other core portions are the same as those of the other core portions 346b to 346k.
Further, when the ends 341 and 342 on the side not connected to the other core portions of the longitudinal ends of the regions constituting the yokes of the two core portions 346a and 346l at both ends abut against each other, the above-mentioned notch is formed. The shape and size of the notch are determined so that the sides constituting the region (two sides constituting the regions 343a to 343k) abut each other. As described above, the portions abutted in this way form the second cut surface.

When manufacturing a folded core, first, the electromagnetic steel sheet 350 has a planar shape of the electromagnetic steel sheet constituting the folded core, and the regions (for example, regions 344) constituting the teeth of the stator core are arranged in a row. Is punched out. At this time, the longitudinal direction of the region constituting the teeth of the stator core (for example, region 344) faces the L direction of the electromagnetic steel sheet 350, and the longitudinal direction of the region constituting the yoke of the stator core (for example, region 345) is the electrical steel sheet. Make it face the C direction of 350. It should be noted that it is the same as the split core that the longitudinal direction of the region constituting the teeth of the stator core and the L direction of the electrical steel sheet 350 need to be substantially the same.

The other core portion 346b, 346k of the end portion of the electrical steel sheet punched in this manner in the longitudinal direction of the region constituting the yoke of the two core portions 346a and 346l at both ends described above. The punched electrical steel sheet is deformed so that the ends 341 and 342 on the side not connected to the grain abut against each other. That is, the position (for example, position 347) corresponding to the outer peripheral surface of the stator core of the end portion in the longitudinal direction of the region constituting the yoke of the core portion 346a to 346k on the side connected to the other core portion is set. Transform. Then, the sides constituting the above-mentioned notch formed in the punched electrical steel sheet are butted against each other to form an annular shape as a whole. A stator core is formed by stacking a plurality of annular electromagnetic steel sheets so that the adjacent plate surfaces of the annular electromagnetic steel sheets thus obtained are aligned with each other. A stator core is configured by stacking a plurality of punched electrical steel sheets so that the adjacent plate surfaces of the punched electrical steel sheets meet each other, and then deforming them in an annular shape as described above. You may. If necessary, processing for fixing the electromagnetic steel sheet constituting the bent core, such as welding or caulking, is performed. Further, the bent core is fixed to the case by shrink fitting or the like.

As shown in FIG. 3B, even in the bent core, as in the case of the split core, the number of parts not used as the stator core is reduced, and the coil winding method can be made more efficient, so that the copper loss of the rotary electric machine is reduced. It can be reduced.
In the following description, the split core will be described as an example, but even if it is a bent core, the stator core can be designed in the same manner as the split core.

<Shape parameter acquisition unit 101, shape parameter acquisition step S201>
The shape parameter acquisition unit 101 inputs the shape parameters of the split core based on the operator's operation on the user interface of the stator core design device 100.
Shape parameters include tooth width, yoke width, radial area, and circumferential area. Further, the shape parameter acquisition unit 101 may acquire the shape parameter of the divided core by automatically calculating the shape parameter of the split core without the operator's operation on the user interface of the stator core design device 100. For example, the shape parameter acquisition unit 101 obtains shape parameters by automatically calculating the tooth width, yoke width, radial area, and circumferential area based on electronic data such as CAD data representing the shape of the split core. May be.

FIG. 4 is a diagram illustrating an example of a tooth width and a yoke width.
The yoke width YW is a value obtained by subtracting the inner diameter from the outer diameter of the stator core at the position of the center of the slot in the circumferential direction of the stator core. In the example shown in FIG. 4A, the yoke width YW is a value obtained by subtracting the inner diameter from the outer diameter of the stator core at positions 401 and 402, and in the example shown in FIG. 4B, the yoke width YW is the position 403. , 404 is a value obtained by subtracting the inner diameter from the outer diameter of the stator core.

The teeth width TW is the circumferential length of the stator core at the center position of the teeth straight line region. Here, the teeth straight line region is the region of the longest straight line among the straight lines constituting the end portion of the teeth in the circumferential direction of the stator core in the cross section of the divided 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 the circumferential direction of. In the example shown in FIG. 4A, the straight line connecting the positions 411 and 421 and the straight line connecting the positions 413 and 414 are the teeth straight line regions, and in the example shown in FIG. 4B, the position 415. The straight line connecting 416 to each other and the straight line connecting positions 417 and 418 to each other are the teeth straight line regions. Further, in the example shown in FIG. 4A, the central position of the teeth straight line region is position 421, 422, and in the example shown in FIG. 4B, the central position of the teeth straight line region is position 423. 424.

FIG. 4A shows, for example, the case where the length of the teeth in the circumferential direction of the stator core is constant in the teeth straight line region. On the other hand, FIG. 4B shows an example in which the length of the slot in the circumferential direction of the stator core is constant. Therefore, in the example shown in FIG. 4A, it is the length of the teeth in the circumferential direction of the stator core, and the length in the teeth straight line region is constant regardless of the location. On the other hand, in the example shown in FIG. 4B, it is the length of the teeth in the circumferential direction of the stator core, and the length in the teeth straight line region varies depending on the location.

FIG. 5 is a diagram illustrating an example of a radial area and a circumferential area. In FIG. 5, the double-headed arrow line conceptually indicates the direction of the magnetic flux.
In FIG. 5, the radial area is the area of the radial region indicated by the diagonal line. The radial region is a region in which only the magnetic characteristics in the L direction are considered when evaluating the iron loss of the stator core. The radial region includes a yoke region and a teeth region.

The yoke portion region is a first point 501 which is a point at the center position in the circumferential direction of the stator core in the region constituting the outer peripheral surface of the stator core in the cross section of the divided core when cut in the direction perpendicular to the axis of the stator core. It is a region surrounded by a triangle having a second point 502 and a third point 503, which are points at two positions closest to the outer peripheral surface of the stator core in the teeth straight line region. The first point 501 refers to the position of the center of the teeth in the circumferential direction of the stator core (divided core) and the axis of the stator core in the cross section when the stator core (divided core) is cut in the direction perpendicular to the axis of the stator core. , The position of the intersection of the virtual line passing through and the outer peripheral surface of the stator core.
The teeth portion region crosses the second point 502 and the third point 503 closest to the outer peripheral surface of the stator core in the teeth linear region in the region of the cross section of the divided core when cut in the direction perpendicular to the axis of the stator core. It is a region on the shaft side of the stator core with respect to the virtual line 504 connected to.

In FIG. 5, the circumferential area is the area of the circumferential region which is a region (white portion) other than the radial region indicated by the diagonal line, and the stator core (divided core) is cut in the direction perpendicular to the axis of the stator core. It is a value obtained by subtracting the radial area from the area of the cross-sectional area of the case. The circumferential region is a region in which only the magnetic characteristics in the C direction are considered when evaluating the iron loss of the stator core. The circumferential region is a region of the cross section of the split core when cut in the direction perpendicular to the axis of the stator core, excluding the radial region.

As shown in FIG. 3B, the cross section of the bent core in the direction perpendicular to the axis of the stator core can be regarded as equivalent to the combination of the cross sections of the split core in the direction perpendicular to the axis of the stator core. That is, in the above description, the cross section of the divided core is one of the regions that are periodically repeated with the deformation position (for example, the position corresponding to the position 347) of the electromagnetic steel sheet constituting the folded steel sheet as a boundary in the circumferential direction of the stator core. The cross section is perpendicular to the axis of the stator core in one area.

The shape parameter acquisition unit 101 inputs a plurality of sets of the shape parameters (teeth width, yoke width, radial area, and circumferential area) as described above (that is, for each of the plurality of candidates for the shape of the stator core). You can enter the shape parameters).

<Shape index derivation unit 102, shape index derivation step S202>
_{The shape index deriving unit 102 derives the shape index S index} based on the shape parameters (teeth width, yoke width, radial area, and circumferential area) input by the shape parameter acquisition unit 101. As described above, when a plurality of sets of shape parameters (teeth width, yoke width, radial area, and circumferential area) are input by the shape parameter acquisition unit 101, the shape index derivation unit 102 sets each set. On the other hand, the shape index S _index is derived. _Assuming that the tooth width is TW [mm], the yoke width is YW [mm], the radial area is LS [mm ² ], and the circumferential area CS [mm ² ], the shape index S index is the following equation (1). Represented by. The shape index S _index is a dimensionless quantity.
S _index = (CS ÷ LS) × (2 × TW ÷ YW) ² ... (1)

The radial area LS and the circumferential area CS of the equation (1) are the same as the area of one divided core and the area of the entire stator core. For example, when the stator core is composed of 25 divided cores, the CS of the formula (1) is 25 × CS and the LS is 25 × LS, so that (25 × CS) ÷ (25 × LS) = ( CS ÷ LS).

Here, the process of obtaining the equation (1) will be described.
In recent years, there has been an increasing demand for miniaturization of rotary electric machines such as motors, and in order not to reduce the output of the rotary electric machine, the rotary electric machine is operated at a frequency higher than the commercial frequency, for example, 400 [Hz] to several [kHz]. The number of cases of driving is increasing. Therefore, it is difficult to accurately predict the motor iron loss only from the material properties of the iron loss at the commercial frequency.

Therefore, the present inventors have verified in detail the relationship between the shape of the stator core and the iron loss of the stator core for a motor driven at 400 [Hz] in the case where various motors are operated under various conditions. did.
Here, a motor with 18 slots, 6 poles, and a stator core with an outer diameter of 250 [mm] has a rotation speed of 8000 [rpm] (equivalent to an excitation frequency f = 400 [Hz]) and a torque of 6.0 [Nm] (equivalent to an excitation frequency f = 400 [Hz]). An example is given when an evaluation is made in the case of operation with a maximum magnetic flux density B = 1.0 [T]) and an output of 5 [kW]. _{Further, here, the average value W 10/400} (L + C) of the iron loss in the L direction and the iron loss in the C direction at a maximum magnetic flux density of 1.0 [T] and an excitation frequency of 400 [Hz] is 14.0 [. W / kg], and an example is given in which a stator core is constructed using a material having an LC ratio of 1.0 (there is no difference in iron loss between the L direction and the C direction). Here, the iron loss is a value measured according to JIS C 2550-1 (2011) “Electromagnetic Steel Strip Test Method Part 1: Method for Measuring Magnetic Steel Strip with Epstein Tester”.

As described above, the tooth width, the yoke width, the radial area, and the circumferential area were selected as the parameters of the shape of the stator core that affect the iron loss of the stator core. This is based on the following idea.
First, in order to compare the difference in the shape of the stator core under the condition that the torque is constant, it is considered that the magnitude of the magnetic flux density in the teeth is constant regardless of the shape of the core. Then, the iron loss of the teeth is determined according to the magnitude of the magnetic flux density of the teeth and the area of the teeth. Next, the magnitude of the magnetic flux density of the yoke is determined according to the ratio between the length of the teeth in the circumferential direction of the stator core and the length of the yoke in the circumferential direction of the stator core. Correspondingly, the iron loss of the yoke is determined. The iron loss of the stator core can be obtained by adding the iron loss of these teeth and the iron loss of the yoke.

As described above, the length of the teeth in the circumferential direction of the stator core and the length of the yoke in the circumferential direction of the stator core affect the iron loss of the stator core, as shown in FIGS. 4 (a) and 4 (b). Further, depending on the shape of the stator core, the length of the teeth in the circumferential direction of the stator core and the length of the yoke in the circumferential direction of the stator core are not always constant. Therefore, it was decided to adopt the above-mentioned tooth width and yoke width as representative values of these lengths.

Further, as shown in FIG. 5, the direction of the magnetic flux changes at the connection portion between the tooth and the yoke. Therefore, a rotating magnetic flux is generated at the connection portion between the tooth and the yoke. Therefore, strictly speaking, the iron loss at the connection portion between the teeth and the yoke is obtained by the magnetic characteristics corresponding to the angle between the L direction and the C direction. However, even if the iron loss is calculated based on the magnetic characteristics of the radial region in the L direction and the other regions in the C direction at the connection portion between the teeth and the yoke, the iron loss of the entire stator core is not significantly affected. In order to reduce the number and reduce the calculation load, we decided to consider only the magnetic characteristics in the L and C directions.

As described above, the electrical steel sheets 330 and 350 have shapes that match the planar shapes of the split core and the bent core so that the longitudinal direction of the tooth region faces the L direction and the longitudinal direction of the yoke region faces the C direction. It is punched out with (see Fig. 3). Further, as shown in FIG. 5, a magnetic flux flows along the longitudinal direction of the teeth, the direction changes to the magnetic flux at the connection portion between the teeth and the yoke, and the magnetic flux flows in the circumferential direction of the stator core in the yoke. The longitudinal direction of the yoke is the C direction, but the magnetic flux tends to flow along the L direction as compared with the C direction. Therefore, in the yoke, the closer the position in the longitudinal direction (circumferential direction of the stator core) is to the center of the teeth, the more easily it is affected by the magnetic flux in the L direction, and the position in the lateral direction (diameter direction of the stator core). However, the closer the region is to the teeth, the more easily it is affected by the magnetic flux in the L direction. Therefore, in the present embodiment, only the magnetic characteristics in the L direction are considered for the region surrounded by the triangle having the first point 501, the second point 502, and the third point 503 as the vertices shown in FIG. The radial region was used.

FIG. 6 is a diagram showing an example of the shape of the split core. FIG. 7 is a diagram showing the shape parameters (yoke width, tooth width, circumferential area, radial area) of the cores A to D of the four types of shapes shown in FIG. 6 and the shape index S _index in a table format. The values of the shape parameters (yoke width, tooth width, circumferential area, radial area) of each of the cores A to D are relative values when the value of the core A is 1.00.

The present inventors have studied a motor having a stator core using cores A to D having four different shapes shown in FIG. It should be noted that each motor has the same configuration except for the stator core. In FIG. 6, the shape of the core is simply approximated to a T shape in order to clarify the difference in the shape parameters. From FIGS. 6 and 7, the characteristics of the cores B to D with respect to the core A can be said as follows.
First, in the core B, the yoke width is significantly small, and the radial area is conversely increased. The core C has a small yoke width and a small circumferential area, and has a relatively large radial area. The area ratio of the teeth and the yoke of the core D is not significantly different from that of the core C, but the teeth width and the yoke width are small and miniaturization is aimed at.

The present inventors have verified the relationship between these characteristics and the iron loss of each core A to D. FIG. 8 shows an example of the relationship between the tooth width / yoke width and the iron loss of the stator core (FIG. 8A), and an example of the relationship between the radial area / circumferential area and the iron loss of the stator core (FIG. 8 (FIG. 8)). b)) is a figure which shows.

As shown in FIGS. 8 (a) and 8 (b), even if only the tooth width and the yoke width or only the radial area and the circumferential area are used as the shape parameters, the shape parameters and the iron loss of the stator core are different. Correlation is low. As described in Patent Document 1, it can be seen that the iron loss of the stator core cannot be accurately evaluated only by the ratio (= Y / Th) of the width Y of the core back portion to the width Th of the teeth portion.

Therefore, the present inventors have an idea that the iron loss of the stator core may be evaluated by using a shape parameter that considers both the ratio of the tooth width to the yoke width and the ratio of the circumferential area to the radial area. Obtained. Then, as a result of examining an index having a high correlation with iron loss for the stator cores of various shapes and materials including the above-mentioned shapes and materials, the present inventors have found _{the shape index S index of the equation (1).} ..
FIG. 9 is a diagram showing an example of the relationship between the _{shape index S index and the iron loss of the stator core.} As shown in FIG. 9, _{it can be seen that the relationship between the shape index S index} and the iron loss of the stator core is in a substantially direct proportional relationship and has a high correlation. Therefore, if the shape _{of the stator core is determined so that the value of the shape index S index} becomes small, it is possible to reduce the iron loss of the stator core.

<Shape index determination unit 103, shape index determination step S203>
As described above, it is possible to minimize the iron loss of the stator core by adopting the candidate having the smallest _{shape index S index} among the candidates for the shape of the stator core. In the example shown in FIG. 6, as shown in FIG. 9, it can be seen that among the cores A to D, the iron loss of the stator core in the shape of the core A is minimized. On the other hand, the shape of the stator core is determined in consideration of the output of the rotary electric machine, the installation space of the rotary electric machine, and the like, depending on the intended use of the rotary electric machine (motor). Therefore, for example, if miniaturization is the highest priority and low iron loss is the second priority, the shape of the core D, which is the smallest and has the second smallest iron loss, may be adopted.

Therefore, the shape index determination unit 103 inputs a plurality of sets of shape parameters as shape parameters (teeth width, yoke width, radial area, and circumferential area) for the shape candidates of the stator core by the shape parameter acquisition unit 101. If, from the derived shape index S _index for each of the sets by the shape index deriving unit 102, determines the shape index S _index to define the shape of the stator core.

For example, the shape index determining unit 103 has a shape index S _index for each of a plurality of sets of shape parameters, and shape parameters (teeth width, yoke width, radial area, and circumference) used when deriving the shape index S _index. Information on the direction area) is displayed on the computer display. _{From this display, the operator determines the optimum shape index S index} as the shape index of the stator core according to the criteria as described above, and operates and specifies the user interface of the stator core design device 100. Shape index determination unit 103, using the user interface of the stator core design apparatus 100 inputs the specified shape index S _index by the operator, the shape index S _index, determined as the shape index S _index to define the shape of the stator core.

Further, the shape index determination unit 103 can automatically _{determine the shape index S index that determines the shape of the stator core.} For example, the shape index determination unit 103, a shape index S _index when evaluation value represented by the weighted linear sum of the plurality of indicators including the shape index S _index is minimized, the shape index S _index defining the shape of the stator core Can be determined as. For example, the outer shape of the stator core when the core i is used is Di, the shape index when the core i is used is S _index i, the _{weight coefficient for the shape index S index} i is k1, and the outer shape of the stator core is the weight coefficient for Di. When is k2, the evaluation value J1 can be expressed by the following equation (2).
J1 = k1 × S _index i + k2 × Di ・ ・ ・ (2)

The weighting coefficients k1 and k2 _{indicate the balance between the evaluation of the shape index S index} i and the outer shape of the stator core with Di. For example, when _{the outer shape Di of the stator core is used as an important evaluation index rather than the shape index S index} i (iron loss), the value of the weighting factor k2 is made smaller than the value of the weighting factor k1. The weighting coefficients k1 and k2 are values specified in advance by the operator. Incidentally, if the weighting factor k2 0 (zero), the minimum shape index S _index is, a shape index S _index to define the shape of the stator core. In the example shown in the equation (2), the iron loss of the stator core can be evaluated by _{k1 × S index i.}

Further, when a set of shape parameters (teeth width, yoke width, radial area, and circumferential area) is input by the shape parameter acquisition unit 101, the shape index determination unit 103 is derived by the shape index derivation unit 102. The shape index S _index and the information of the shape parameters (teeth width, yoke width, radial area, and circumferential area) used when the _{shape index S index is derived are displayed on the computer display.} From this display, the operator _{determines whether or not the shape index S index} is appropriate, and if not, operates the user interface of the stator core design device 100 to respecify the shape parameter. The shape parameter acquisition unit 101 inputs the shape parameter redesignated in this way. The operator can input the shape parameter by the shape parameter acquisition unit 101, derive the shape index S _index by the shape index derivation unit 102, and display the _{shape index S index} or the like by the shape index determination unit 103. _{Repeat until index} is specified as appropriate. Shape index determination unit 103, when it by the operator the shape index S _index is appropriate is designated, the shape index S _index, determined as the shape index S _index to define the shape of the stator core.

_{Further, if an appropriate value as the shape index S index} is obtained from the past results, for example, according to the specifications of the rotary electric machine, a threshold value for the _{shape index S index} may be set based on the value. good. In this case, for example, the shape index determination unit 103, the shape index deriving unit 102 shape index S _index derived by the, if below a threshold, the shape index S _index, a shape index S _index defining the shape of the stator core Can be decided.

Then, a stator core having a shape determined by the shape parameters (teeth width, yoke width, radial area, and circumferential area) used when deriving the _{shape index S index} determined as described above is designed. The design may be performed by the designer or may be performed by the stator core design device 100. The shape parameters other than the tooth width, the yoke width, the radial area, and the circumferential area may be appropriately determined according to the specifications of the rotary electric machine (motor) to which the stator core is applied. Then, a stator core having the shape is manufactured by a known method.

As described above, in the present embodiment, the stator core design device 100 derives the shape index S _index ^{represented by (CS ÷ LS) × (2 × TW ÷ YW) 2.} Therefore, the shape _{of the stator core can be designed based on the value of the shape index S index} (an index capable of evaluating the iron loss of the stator core as an index relating to the shape of the stator core). Therefore, it is possible to easily design the shape of the stator core that can reduce the iron loss.

(Second embodiment)
Next, the second embodiment will be described. In the first embodiment, the case of designing the shape of the stator core has been described as an example. In this embodiment, a case where the shape of the stator core is designed as in the first embodiment and then the material used for the stator core is designed will be described as an example. As described above, in this embodiment, the point of designing the material used for the stator core is added to the first embodiment. Therefore, in the description of the present embodiment, the same parts as those of the first embodiment are designated by the same reference numerals as those shown in FIGS. 1 to 9, and detailed description thereof will be omitted. In this embodiment as well as in the first embodiment, the split core will be described as an example, but even if it is a bent core, the stator core can be designed in the same manner as the split core. Further, also in this embodiment, as in the first embodiment, a case where an electromagnetic steel sheet (at least one of a non-oriented electrical steel sheet and a grain-oriented electrical steel sheet) is used as a soft magnetic material plate will be described as an example.

FIG. 10 is a diagram showing an example of a functional configuration of the stator core design device 1000. FIG. 11 is a flowchart illustrating an example of a stator core design method using the stator core design device 1000. The hardware of the stator core design device 1000 can be realized by, for example, the same hardware as the stator core design device 100 of the first embodiment.

<Material property acquisition unit 1001, material property acquisition step S1101>
The material property acquisition unit 1001 inputs the material parameters of the electrical steel sheet used for the stator core based on the operator's operation on the user interface of the stator core design device 1000.

Material parameters include W _{b / f} (L + C), W _{b / f} (L), W _{b / f} (C). W _{b / f} (L) is the iron loss [W / kg] in the L direction of the electrical steel sheet when the maximum magnetic flux density is B (= b ÷ 10) [T] and the excitation frequency is f [Hz]. Is. W _{b / f} (C) is the iron loss [W / kg] in the C direction of the electrical steel sheet when the maximum magnetic flux density is B (= b ÷ 10) [T] and the excitation frequency is f [Hz]. Is. W _{b / f (L + C) is the iron loss W b / f} (L) in the L direction of the electromagnetic steel plate when the maximum magnetic flux density is B [T] and the excitation frequency is f [Hz], and the maximum magnetic flux. When the density is B (= b ÷ 10) [T] and the excitation frequency is f [Hz], the average value with the _{iron loss W b / f (C) in the C direction of the electromagnetic steel plate (= {W b). / f} (C) + W _{b / f} (L)} ÷ 2). For each iron loss, please refer to JIS C 2550-1 (2011) "Electrical Steel Strip Test Method Part 1: Method of Measuring Magnetic Steel Strip with Epstein Tester" or JIS C 2556 "Electrical Steel with Single Plate Tester". It is obtained by "Measuring method of magnetic characteristics of band". For example, when the maximum magnetic flux density is 1.0 [T] and the excitation frequency is 50 [Hz], the iron loss in the L direction, the iron loss in the C direction, and the iron loss in the L direction and the C direction of the electromagnetic steel sheet The average value of iron loss is written as W _10/50 (L), W _10/50 (C), and W _10/50 (L + C), respectively.

In the following description, the iron loss in the L direction of the electrical steel sheet when the maximum magnetic flux density is B [T] and the excitation frequency is f [Hz] is referred to as the iron loss in the L direction, if necessary. .. Further, the iron loss in the C direction of the electromagnetic steel sheet when the maximum magnetic flux density is B [T] and the excitation frequency is f [Hz] is referred to as C direction iron loss, if necessary. Further, the average value of the iron loss in the L direction and the iron loss in the C direction when the maximum magnetic flux density is B [T] and the excitation frequency is f [Hz] is referred to as an average iron loss in the LC direction, if necessary.
The material property acquisition unit 1001 _{inputs a plurality of sets of material parameters (W b / f} (L + C), W _{b / f} (L), W _{b / f} (C)) as described above (that is, the stator core. Enter the material parameters for each of the multiple candidates for the material).

<Material index derivation unit 1002, material index derivation step S1102>
_{The material index derivation unit 1002 includes a shape index S index} determined as a shape index of the stator core by the shape index determination unit 103, _{and material parameters (W b / f} (L + C), W _{b /} ) input by the material property acquisition unit 1001. _{The material index W index} is derived based on f (L) and W _{b / f} (C)). _{The material index derivation unit 1002 derives the material index W index} for each of the plurality of sets of material parameters input by the material property acquisition unit 1001.

The material index W _index is expressed by the following equation (3), where _{the representative value of the LC direction average iron loss WB / f} (L + C) input by the material property acquisition unit 1001 _{is Wave [W / kg].} To.
W _index = _Wave × S _index / (W _{b / f} (L + C)) + (W _{b / f} (C) / W _{b / f} (L)) ・ ・ ・ (3)
As the representative value W _ave of the LC directions average iron loss _{W b / f (L + C} ), for example, can be used an average value or median value of the LC directions average iron loss _{W b / f (L + C} ). Hereinafter, a W _ave, shall be used the average value of the LC directions average iron loss _{W b / f (L + C} ).

Here, the process of obtaining the equation (3) will be described.
The present inventors, for a motor driven at 400 [Hz], set various motors under various conditions regarding the relationship between the iron loss characteristics of the material of the stator core and the iron loss of the stator core. I examined it in detail when it worked with. Here, as in the first embodiment, a motor having 18 slots, 6 poles, and a stator core with an outer diameter of 250 [mm] is used at a rotation speed of 8000 [rpm] (equivalent to an excitation frequency f = 400 [Hz]) and torque. An example is given when an evaluation is made when the product is operated at 6.0 [Nm] (equivalent to a maximum magnetic flux density B = 1.0 [T]) and an output of 5 [kW]. Further, the shape of the stator core is a shape _{based on the shape index S index} of the core D described in the first embodiment, and the stator core is configured by using eight kinds of electromagnetic steel sheets (materials a to h) shown in FIG. Take the case as an example. FIG. 12 shows the average iron loss W _10/400 (L + C) in the LC direction and the LC ratio (= W _10/400 (C) ÷ W _10/400 (L)) of the eight materials a to h in tabular form. It is a figure. _{For example, the average iron loss W 10/400} (L + C) in the LC direction may change depending on the chemical composition of the electrical steel sheet, the thickness of the electrical steel sheet, and the like. Therefore, for example, even if the chemical composition is the same, different materials can be used if the thickness is different. Further, the candidate material may include only non-oriented electrical steel sheets, only grain-oriented electrical steel sheets, or both non-oriented electrical steel sheets and grain-oriented electrical steel sheets.

FIG. 13 is a diagram showing an example of the relationship between the _{average iron loss W 10/400 (L + C) in the LC direction and the iron loss of the stator core.}
As shown in FIG. 13 (a), _{it can be seen that the smaller the value of the average iron loss W 10/400} (L + C) in the LC direction, the smaller the iron loss of the stator core tends to be.
FIG. 13 (b) is an enlarged view showing the iron loss of the stator core in the vicinity of 14.0 [W / kg] _{in the LC direction average iron loss W 10/400 (L + C) in FIG. 13 (a).} As shown in FIG. 13 (b), the iron loss _{of the stator core in which the average iron loss W 10/400} (L + C) in the LC direction is around 14.0 [W / kg] is four kinds of materials c, d, e, and f. The minimum value is 55.0 [W] and the maximum value is 59.9 [W]. At the level with the smallest iron loss, the iron loss can be reduced by about 8 [%] compared to the level with the largest iron loss. It turned out to be.

We have examined this factor. FIG. 14 is a diagram showing an example of the relationship between the LC ratio and the iron loss of the stator core. As shown in FIG. 14, the present inventors have _{an LC ratio (= W 10/400} (C), which is the ratio of the C-direction iron loss W _{10/400 (C) to the L-direction iron loss W 10/400 (L).} ) ÷ W _10/400 (L)) was found to have a high correlation with the iron loss of the stator core. Specifically, the present inventors have found that if the average iron loss W _10/400 (L + C) in the LC direction is the same material, the larger the LC ratio (the greater the anisotropy of the iron loss in the L and C directions). ), It was found that the iron loss of the stator core is reduced.

_{Therefore, if a material having a small average iron loss W 10/400} (L + C) in the LC direction and a large LC ratio is selected as the material of the stator core, the iron loss of the stator core can be reduced. However, for example, when comparing two types of materials, if one material has a _{smaller average iron loss W 10/400} (L + C) in the LC direction than the other material, but the LC ratio is also smaller, which material is used. It's not clear if you should choose.
Therefore, the present inventors have _{compared the} average iron loss W 10/400 (L + C) in the LC direction with the LC ratio (= W _10/400 (C) ÷ W _10/400 (L)). _{Using the shape index S index} described in the first embodiment and _{the representative value Wave} of the LC direction average iron loss W _{b / f} (L + C) of a plurality of candidate materials, the LC direction average iron loss W _{10 I got the idea that if / 400} (L + C) and the LC ratio can be compared equally, the iron loss of the stator core can be evaluated correctly. Then, as a result of examining an index having a high correlation with iron loss for the stator cores of various shapes and materials including the above-mentioned shapes and materials, the present inventors have found _{the material index W index of the equation (3).} ..

Next, it is shown that the material index W _index has a high correlation with iron loss regardless of the shape of the stator core.
FIG. 15 is a diagram showing an example of the relationship between the _{material index W index and the iron loss of the stator core.} In FIG. 15A, the shape of the stator core is the shape of the core A described in the first embodiment, and the electromagnetic steel sheet used for the stator core is the electromagnetic steel of the eight kinds of materials a to h shown in FIG. _{The results of finding the relationship between the material index W index} and the iron loss of the stator core when the stator core is configured as a steel plate and the motor is configured and operated according to the specifications described above using the stator core are shown. In FIGS. 15 (b), 15 (c), and 15 (d), the shapes of the stator cores are changed from the core A to the core B, the core C, and the core D described in the first embodiment, respectively. The result of the case is shown.

As shown in FIG. 15 (a) ~ FIG. 15 (d), regardless of the shape of the stator core, as the material index W _index is large, the iron loss of the stator core becomes smaller, the material index W _index and the stator core iron loss , It can be seen that there is a high correlation. Therefore, it can be said that the material index W _index is useful as an index for selecting the material of the stator core. The above was the same even if the maximum magnetic flux density B and the excitation frequency f were different.

Here, the magnetic flux density and the excitation frequency in the stator core are determined according to the NT characteristics (relationship between the rotation speed and the torque) of the motor and the like. Therefore, among the evaluation indexes (most frequently used rotation speed / torque, maximum torque value, maximum rotation speed, etc.), the maximum magnetic flux density B and excitation frequency f of the stator core determined from the most important evaluation index are set. , The maximum magnetic flux density B and the excitation frequency f in the material parameters (W _{b / f} (L + C), W _{b / f} (L), W _{b / f (C)).} Further, for example, the maximum magnetic flux density B and the excitation frequency f of the stator core are determined for each of the set of the plurality of evaluation indexes, and the set in which the evaluation value represented by the weighted linear sum of the plurality of evaluation indexes becomes the maximum or the minimum. _{In the material parameters (W b / f} (L + C), W _{b / f} (L), W _{b / f} (C)), the maximum magnetic flux density B and the excitation frequency f of the stator core corresponding to the specified set are specified. It can also be determined as the maximum magnetic flux density B and the exciting frequency f.

<Material index determination unit 1003, material index determination step S1103>
As described above, it is possible to minimize the iron loss of the stator core by adopting the material having the maximum value of the _{material index W index} among the candidate materials as the material of the stator core. In the examples shown in FIGS. 15 (a) to 15 (d), it can be seen that if the material h is used as the material of the stator core among the materials a to h, the iron loss of the stator core is minimized. On the other hand, the material of the stator core is determined in consideration of cost and the like. Therefore, for example, cost reduction may be a re-priority and iron loss reduction may be a second priority.

Therefore, the material index determination unit 1003 _{determines the material index W index} that determines the material of the stator core from _{the plurality of material index W indexes derived by the material index derivation unit 1002.
For example, the material index determination unit 1003 has a material index W index} for a plurality of materials that are candidates for the material of the stator core, and a material parameter (W _{b / f} (L + C), used when deriving the material index W _index. The information of W _{b / f} (L) and W _{b / f} (C)) is displayed on the computer display. _{From this display, the operator determines the optimum material index W index} as the material index of the stator core according to the criteria as described above, and operates and specifies the user interface of the stator core design device 1000. Materials index determination unit 1003, using the user interface of the stator core design apparatus 1000 inputs the specified material index W _index by the operator, the material index W _index, determined as the material index W _index to determine the material of the stator core.

Further, the material index determination unit 1003 can also automatically _{determine the material index W index that determines the material of the stator core.} For example, the material index W _index when the evaluation value represented by the weighted linear sum of a plurality of indexes including the material index W _index becomes maximum can be determined as the _{material index W index} that determines the material of the stator core. For example, when the cost of the material j is Cj, the material index when the material j is used is W _index j, the _{weighting coefficient for the material index W index} j is k3, and the weighting coefficient for the material cost Cj is k4, the evaluation is performed. The value J2 can be expressed by the following equation (4).
J2 = k3 × W _index j + k4 × (1 / Cj) ・ ・ ・ (4)
Incidentally, if the weighting factor k4 0 (zero), the maximum of the material index W _index becomes the material index W _index to determine the material of the stator core. In the example shown in the equation (4), the iron loss of the stator core can be evaluated by _{k3 × W index j.}

_{Further, if an appropriate value as the material index W index} is obtained from the past results, for example, according to the specifications of the rotary electric machine, a threshold value for the _{material index W index} may be set based on the value. good. In this case, for example, the material index determination unit 1003, the material index deriving unit 1002 material index W _index derived by the, if above a threshold, the material index W _index, as the material index W _index to determine the material of the stator core Can be decided.

First, the shape determined by the shape parameters (teeth width, yoke width, radial area, and circumferential area) used when deriving the _{shape index S index} determined as described in the first embodiment. Design the stator core. At this time, the material parameters (W _{b / f} (L + C), W _{b / f} (L), W _{b / f} (C)) _{used in deriving the material index W index determined as described above).} The electrical steel sheet having the above is used as the electrical steel sheet used for the stator core. The design may be performed by the designer or by the stator core design device 1000. Incidentally, the teeth width, the yoke width, the radial area, and the shape parameters other than the circumferential direction area, LC direction average iron loss _{W b / f (L + C} ), L -direction iron losses W _{b / f} (L), and C direction Material parameters other than iron loss W _{b / f} (C) may be appropriately determined according to the specifications of the rotary electric machine (motor) to which the stator core is applied. Then, a stator core having the shape is manufactured by a known method.

As described above, in the present embodiment, the stator core design device 1000 is represented by _Wave × S _index / (W _{b / f} (L + C)) + (W _{b / f} (C) / W _{b / f} (L)). The material index W _index to be obtained is derived. Therefore, the material _{of the stator core is designed based on the value of the material index W index} (an index capable of evaluating the iron loss of the stator core as an index relating to the material of the stator core). Therefore, it is possible to easily design the shape and material of the stator core that can reduce the iron loss.

In the embodiment of the present invention described above, at least a part of the processing of the stator core design devices 100 and 1000 may be realized without using hardware.
Further, the embodiment of the present invention described above can also be realized by executing a program by a computer. Further, a computer-readable recording medium on which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a non-volatile memory card, a ROM, or the like can be used.
In addition, the embodiments of the present invention described above are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. It is a thing. That is, the present invention can be implemented in various forms without departing from the technical idea or its main features.

100, 1000: Stator core design device, 101: Shape parameter acquisition unit, 102: Shape index derivation unit, 103: Shape index determination unit, 1001: Material parameter acquisition unit, 1002: Material index derivation unit, 1003: Material index determination unit

Claims (17)

It is a design index determination method for a stator core that has a yoke and a plurality of teeth and is configured by stacking soft magnetic materials.
A shape parameter acquisition step of acquiring information including a circumferential area, a radial area, a yoke width, and a tooth width as shape parameters for the shape candidate of the stator core, and a process of acquiring the shape parameters.
A shape index deriving step for deriving a shape index, which is an index related to the shape of the stator core, based on the shape parameter for one candidate of the shape of the stator core.
It has a shape index determining step of determining the shape index satisfying a predetermined condition based on the shape index as a design index of the stator core based on the shape index derived by the shape index deriving step.
The smaller angle between the L direction, which is the rolling direction of the soft magnetic plate, and the longitudinal direction of the teeth is the C direction, which is the direction perpendicular to the rolling direction of the soft magnetic plate, and the above. Smaller than the smaller angle between the teeth and the longitudinal direction,
The yoke width is a value obtained by subtracting the inner diameter from the outer diameter of the stator core at the position of the center of the slot in the circumferential direction of the stator core.
The teeth width is the circumferential length of the teeth at a position in the center of the teeth straight line region.
The teeth straight line region is a region of the longest straight line among straight lines constituting the end portion of the teeth in the circumferential direction of the stator core in a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core. It was obtained for each of the two ends of the teeth in the circumferential direction of the stator core.
The radial area is the sum of the area of the yoke portion region and the area of the teeth portion region.
The yoke portion region is a region surrounded by a triangle having a first point, a second point, and a third point as vertices.
The first point is a virtual line passing through the center position of the teeth in the circumferential direction of the stator core and the axis of the stator core in a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core. And the intersection of the outer peripheral surface of the stator core.
The second point and the third point are on each region of the two teeth straight line regions in one tooth in a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core. Of the positions, it is the point closest to the outer peripheral surface of the stator core.
The tooth portion region is a region of a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core, and the stator core is more than a virtual line connecting the second point and the third point to each other. The area on the axis side,
A method for determining a design index of a stator core, wherein the circumferential area is a value obtained by subtracting the radial area from the area of a cross-sectional area when the stator core is cut in a direction perpendicular to the axis of the stator core. .. In the shape parameter acquisition step, the shape parameters are acquired for each of the plurality of candidates for the shape of the stator core.
In the shape index derivation step, the shape index is derived for each of the plurality of candidates for the shape of the stator core.
In the shape index determination step, the shape index satisfying a predetermined condition based on the shape index is determined from the shape indexes of a plurality of candidates for the shape of the stator core derived by the shape index derivation step. The method for determining a design index of a stator core according to claim 1. In the shape index determination step, the smallest shape index among the shape indexes derived by the shape index derivation step for a plurality of candidates for the shape of the stator core is the shape that satisfies a predetermined condition based on the shape index. The method for determining a design index of a stator core according to claim 2, wherein the determination is made as an index. The shape index shall be obtained by a calculation formula including the product of the first ratio, which is the ratio of the circumferential area to the radial area, and the second ratio, which is the ratio of the teeth width to the yoke width. The method for determining a design index of a stator core according to any one of claims 1 to 3. The shape index S _index is as follows, where the tooth width is TW [mm], the yoke width is YW [mm], the radial area is LS [mm ² ], and the circumferential area is CS [mm ² ]. The method for determining a design index of a stator core according to claim 4, wherein the method is represented by the formula (A).
S _index = (CS ÷ LS) × (2 × TW ÷ YW) ² ... (A) Any of claims 1 to 5, wherein the shape index for the candidate for the shape of the stator core is an index for evaluating the iron loss of the stator core when the shape of the stator core is the candidate shape. The method for determining the design index of the stator core according to item 1. As a material parameter for the material candidate of the stator core, the L-direction iron loss, which is the iron loss in the L direction of the soft magnetic plate when the maximum magnetic flux density is a predetermined value and the excitation frequency is a predetermined value. The C-direction iron loss, which is the iron loss in the C direction of the soft magnetic plate when the maximum magnetic flux density is the predetermined value and the excitation frequency is the predetermined value, and the maximum magnetic flux density is the predetermined value. Information including the L-direction iron loss and the LC-direction average iron loss, which is the average value of the L-direction iron loss and the C-direction iron loss of the soft magnetic plate when the excitation frequency is the predetermined value. The material parameter acquisition step of acquiring each of the plurality of candidates of the material of the stator core, and
A material index derivation step for deriving a material index, which is an index relating to the material of the stator core, based on the shape index and the material parameter.
Based on the material index derived by the material index derivation step, the material index determining step of determining the material index satisfying a predetermined condition based on the material index together with the shape index as the design index of the stator core. The method for determining a design index of a stator core according to any one of claims 1 to 6, wherein the method is characterized by having. The material index determination step is characterized in that the material index satisfying a predetermined condition based on the material index is determined from the material indexes of a plurality of candidates of the material derived by the material index derivation step. The method for determining a design index of a stator core according to claim 7. In the material index determination step, among the material indexes derived by the material index derivation step for a plurality of candidates for the shape of the stator core, the largest material index is the material that satisfies a predetermined condition based on the material index. The method for determining a design index of a stator core according to claim 8, wherein the determination is made as an index. The material index includes a third ratio of the product of the representative value of the LC direction average iron loss and the shape index for a plurality of candidates of the material to the LC direction average iron loss. The stator core according to any one of claims 7 to 9, wherein the stator core is obtained by a calculation formula including a term including a fourth ratio which is a ratio of the iron loss in the C direction to the iron loss in the L direction. Design index determination method. In the material index W _index , the iron loss in the L direction of the soft magnetic plate when the maximum magnetic flux density is B (= b ÷ 10) [T] and the excitation frequency is f [Hz] is W _{b. / f} (L) [W / kg], the maximum magnetic flux density is B (= b ÷ 10) [T], and the excitation frequency is f [Hz], the iron in the C direction of the soft magnetic plate. The soft magnetic plate having a loss of W _{b / f} (C) [W / kg], a maximum magnetic flux density of B (= b ÷ 10) [T], and an excitation frequency of f [Hz]. The C direction of the soft magnetic plate when the iron loss W _{b / f} (L) in the L direction and the maximum magnetic flux density are B (= b ÷ 10) [T] and the excitation frequency is f [Hz]. The average value with the iron loss W _{b / f} (C) is W _{b / f} (L + C), and the representative value of the LC direction average iron loss for the plurality of material candidates is _Wave [W / kg]. The method for determining a design index of a stator core according to claim 10, wherein the shape index is an S _{index and is represented by the following equation (B).}
W _index = _Wave × S _index / (W _{b / f} (L + C)) + (W _{b / f} (C) / W _{b / f} (L)) ・ ・ ・ (B) Any of claims 7 to 11, wherein the material index for the candidate material of the stator core is an index for evaluating the iron loss of the stator core when the material of the stator core is used as the candidate material. The method for determining the design index of the stator core according to item 1. The method for determining a design index of a stator core according to any one of claims 1 to 12, wherein the L direction, which is the rolling direction of the soft magnetic plate, and the longitudinal direction of the teeth substantially coincide with each other. The method for determining a design index of a stator core according to any one of claims 1 to 13, wherein the stator core is a stator core having a plurality of divided cores or a stator core having a bent core. The design of the stator core according to any one of claims 1 to 14, further comprising a design process for designing a stator core having a shape determined by the shape parameter used when deriving the shape index determined by the shape index determination step. Indicator determination method. It is a design index determination device for a stator core that has a yoke and a plurality of teeth and is configured by stacking soft magnetic materials.
As shape parameters for the shape candidates of the stator core, a shape parameter acquisition means for acquiring information including a circumferential area, a radial area, a yoke width, and a teeth width, and
A shape index deriving means for deriving a shape index which is an index related to the shape of the stator core based on the shape parameter for one candidate of the shape of the stator core.
Based on the shape index derived by the shape index deriving means, the shape index determining means for determining the shape index satisfying a predetermined condition based on the shape index as a design index of the stator core is provided.
The smaller angle between the L direction, which is the rolling direction of the soft magnetic plate, and the longitudinal direction of the teeth is the C direction, which is the direction perpendicular to the rolling direction of the soft magnetic plate, and the above. Smaller than the smaller angle between the teeth and the longitudinal direction,
The yoke width is a value obtained by subtracting the inner diameter from the outer diameter of the stator core at the position of the center of the slot in the circumferential direction of the stator core.
The teeth width is the circumferential length of the teeth at a position in the center of the teeth straight line region.
The teeth straight line region is a region of the longest straight line among straight lines constituting the end portion of the teeth in the circumferential direction of the stator core in a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core. It was obtained for each of the two ends of the teeth in the circumferential direction of the stator core.
The radial area is the sum of the area of the yoke portion region and the area of the teeth portion region.
The yoke portion region is a region surrounded by a triangle having a first point, a second point, and a third point as vertices.
The first point is a virtual line passing through the center position of the teeth in the circumferential direction of the stator core and the axis of the stator core in a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core. And the intersection of the outer peripheral surface of the stator core.
The second point and the third point are on each region of the two teeth straight line regions in one tooth in a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core. Of the positions, it is the point closest to the outer peripheral surface of the stator core.
The tooth portion region is a region of a cross section when the stator core is cut in a direction perpendicular to the axis of the stator core, and the stator core is more than a virtual line connecting the second point and the third point to each other. The area on the axis side,
The circumferential area, the area of the region of the cross section when cut the stator core in a direction perpendicular to the axis of the stator core, the stator core of the design index determination device which is a value obtained by subtracting the radial area .. And each step of the stator core design index determination method according to claim 1 5,
A method for manufacturing a stator core , which comprises a step of manufacturing a stator core designed in the design step.

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