JP2021080502A - Laminate core and rotary electric machine - Google Patents

Abstract

To improve magnetic properties of a laminate core.SOLUTION: Caulking parts 113a-113h are formed in a part of the area of a stator core 111, in which a value of magnetic property of an electromagnetic steel sheet 300 is an inferior value to a reference value in a direction parallel to the plate surface of the electromagnetic steel sheet, the direction along a virtual line passing the center axis O and the barycentric positions of the caulking parts 113a-113h.SELECTED DRAWING: Figure 1

Description

The present invention relates to laminated cores and electrical equipment.

As a core used in an electric device such as a rotary electric machine, there is a laminated core formed by laminating a plurality of electromagnetic steel sheets. When forming the laminated core, a plurality of electrical steel sheets are fixed by caulking.
As a technique of this kind, there is a technique described in Patent Documents 1 to 3.

Patent Document 1 describes that a crimped portion having a number of integral multiples of the number obtained by dividing the least common multiple of the number of poles and the number of slots of an electric motor by the number of poles is formed on the teeth of the stator core.
Patent Document 2 describes that a caulking portion is formed in a region of the teeth of the stator core on the rotation direction side of the rotary electric machine and on the tip side of the teeth. The area on the tip side of the teeth is said to be the area surrounded by the center line in the rotation direction of the teeth and the line drawn from the tip of the teeth on the opposite rotation direction to the root of the teeth on the rotation direction side. ing.
Patent Document 3 describes that a caulking portion is formed in a region outside the q-axis magnetic path in the region of the rotor.

Japanese Unexamined Patent Publication No. 2001-258225 Japanese Unexamined Patent Publication No. 2006-340507 Japanese Unexamined Patent Publication No. 2016-220514

However, in Patent Documents 1 to 3, the magnetic properties of the electrical steel sheet have not been examined. Therefore, there is room for improvement in the conventional laminated core for improving the magnetic characteristics.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the magnetic characteristics of the laminated core.

The laminated core of the present invention is a laminated core having a plurality of electromagnetic steel sheets laminated so that the plate surfaces face each other, and has at least one caulked portion formed on the plurality of electromagnetic steel sheets. However, the crimped portion is formed in a region where the value of the magnetic characteristic of the electrical steel sheet is inferior to the reference value, and the reference value is the magnetism of the electrical steel sheet in a plurality of previously measured directions. It is characterized in that it is determined based on the average value of the characteristic values.

The electric device of the present invention is characterized by having the laminated core.

According to the present invention, the magnetic properties of the laminated core can be improved.

It is a figure which shows the 1st example of the structure of a rotary electric machine. It is a top view which shows the 1st example of the structure of a stator core. It is sectional drawing which shows an example of the structure of a stator core. It is a figure which shows the 2nd example of the structure of a rotary electric machine. It is a top view which shows the 2nd example of the structure of a stator core. It is a figure which shows an example of the relationship between a W15 / 50 ratio, an iron loss ratio, and an angle from a rolling direction. It is a figure which shows an example of the relationship between a W15 / 100 ratio, an iron loss ratio, and an angle from a rolling direction. It is a figure which shows the comparative example of the structure of a rotary electric machine.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, in addition to the case where the length, direction, position, etc. match exactly, the case where they match within a range that does not deviate from the gist of the invention (for example, within a range of error that occurs in the manufacturing process) is also included. ..

(First Embodiment)
FIG. 1 is a diagram showing an example of the configuration of the rotary electric machine 100. FIG. 1 is a view (plan view) of the rotary electric machine 100 as viewed from a direction parallel to the central axis O of the rotary electric machine 100. FIG. 2 is a diagram showing an example of the configuration of the stator core 111. FIG. 2 is a view (plan view) of the stator core 111 as viewed from a direction parallel to the central axis O of the stator core 111. In each figure, the XYZ coordinates indicate the relationship of orientation in each figure. The symbol with ● in ○ indicates the direction from the back side to the front side of the paper. Symbols with a cross in the circle indicate the direction from the front side to the back side of the paper.

As shown in FIG. 1, the rotary electric machine 100 includes a stator 110, a rotor 120, a rotary shaft 130, and a case 140. The stator 110 and rotor 120 are housed in a case 140. The stator 110 is fixed to the case 140.

In the present embodiment, as the rotary electric machine 100, an inner rotor type in which the rotor 120 is located inside the stator 110 is adopted. However, as the rotary electric machine 100, an outer rotor type in which the rotor 120 is located outside the stator 110 may be adopted. Further, in the present embodiment, the rotary electric machine 100 is a four-pole 60-slot three-phase squirrel-cage induction motor. However, for example, the number of poles, the number of slots, the number of phases, and the like can be changed as appropriate.

The stator 110 includes a stator core 111 and a winding 112.
The stator core 111 includes an annular core back portion 111a and a plurality of tooth portions 111b. In the following description, the axial direction of the stator core 111 will be referred to as an axial direction, if necessary. Further, the radial direction of the stator core 111 is referred to as a radial direction, if necessary. Further, the circumferential direction of the stator core 111 is referred to as a circumferential direction, if necessary. The axial direction of the stator core 111 is along the central axis O of the stator core 111, the radial direction of the stator core 111 is the direction orthogonal to the central axis O of the stator core 111, and the circumferential direction of the stator core 111 is the circumferential direction of the stator core 111. It is a direction to orbit around the central axis O of.

The core back portion 111a is formed in an annular shape in a plan view of the stator 110 when viewed from the axial direction. The plurality of tooth portions 111b are arranged in a region inside the stator 110 (stator core 111) in the relatively radial direction. Specifically, the plurality of tooth portions 111b project inward in the radial direction (toward the central axis O along the radial direction) from the core back portion 111a. The plurality of tooth portions 111b are arranged at equal intervals in the circumferential direction. In the present embodiment, 60 tooth portions 111b are provided so that the central angle around the central axis O is 6 ° in each tooth portion 111b. The plurality of tooth portions 111b have the same shape and the same size as each other. However, the number, shape, and size of the teeth portions 111b can be changed as appropriate. The winding 112 of the stator 110 is wound around the teeth portion 111b. The winding 112 of the stator 110 may be centrally wound or distributedly wound.

The rotor 120 includes a rotor core 121 and a cage conductor 122. The rotor core 121 is arranged coaxially with the stator 110. The shape of the rotor core 121 is generally a hollow gear shape. A rotating shaft 130 is arranged in the rotor core 121. The rotating shaft 130 is fixed to the hollow portion of the rotor core 121. The cage conductor 122 has a plurality of rotor bars and two end rings. The plurality of rotor bars extend in the axial direction in the region on the outer peripheral side of the rotor core 121, and are arranged at equal intervals in the circumferential direction. In the present embodiment, a case where 37 rotor bars are arranged at equal intervals in the circumferential direction is shown as an example. However, the number of rotor bars is not limited to this. The end ring is connected to the plurality of rotor bars at the axial ends of the plurality of rotor bars. The plurality of rotor bars are arranged in the gear-shaped recesses of the rotor core 121. The size and shape of the gear-shaped recesses of the rotor core 121 are determined so that the rotor core 121 can be arranged. In FIG. 1, the end ring is not shown for convenience of explanation.

FIG. 3 is a diagram showing an example of a cross section of the stator core 111. FIG. 3A is a cross-sectional view taken along the line II of FIG. FIG. 3B is a sectional view taken along line II-II of FIG. As shown in FIGS. 3 (a) and 3 (b), the stator core 111 is a laminated core. The stator core 111 is formed by laminating a plurality of electromagnetic steel sheets 300 so that the plate surfaces (= surfaces facing the direction in which the electromagnetic steel sheets 300 are laminated) face each other with the outer edges aligned. That is, the stator core 111 includes a plurality of electromagnetic steel sheets 300 laminated in the thickness direction. In the following description, the direction in which the plurality of electromagnetic steel sheets 300 are laminated is referred to as a stacking direction, if necessary. The stacking direction coincides with the thickness direction of the electromagnetic steel sheet 300. Further, the stacking direction coincides with the extending direction of the central axis O. Further, when viewed from the stacking direction, the rolling directions RD of the electromagnetic steel sheets 300 constituting the stator core 111 are aligned. The direction in which the central axis O extends is the same as the axial direction (= height direction) of the stator core 111.

Insulating coatings are provided on both sides of the electrical steel sheet 300 in order to improve the workability of the electrical steel sheet and the iron loss of the laminated core. As the substance constituting the insulating film, for example, (1) an inorganic compound, (2) an organic resin, (3) a mixture of an inorganic compound and an organic resin, and the like can be applied. Examples of the inorganic compound include (1) a complex of dichromate and boric acid, and (2) a complex of phosphate and silica. Examples of the organic resin include epoxy-based resin, acrylic-based resin, acrylic styrene-based resin, polyester-based resin, silicon-based resin, and fluorine-based resin.

In order to ensure the insulating performance between the magnetic steel sheets 300 laminated to each other, the thickness of the insulating film (thickness per one side of the electrical steel sheets 300) is preferably 0.1 μm or more. On the other hand, as the insulating film becomes thicker, the insulating effect saturates. Further, as the insulating film becomes thicker, the proportion of the insulating film in the stator core 111 increases, and the magnetic characteristics of the stator core 111 deteriorate. Therefore, the insulating coating should be as thin as possible to ensure the insulating performance. The thickness of the insulating coating is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 2 μm or less. The thickness of the insulating film is the thickness per one side of the electrical steel sheet 300.

As the electromagnetic steel sheet 300 becomes thinner, the effect of improving iron loss gradually saturates. Further, as the electromagnetic steel sheet 300 becomes thinner, the manufacturing cost of the electrical steel sheet 300 increases. Therefore, the thickness of the electrical steel sheet 300 is preferably 0.10 mm or more in consideration of the effect of improving iron loss and the manufacturing cost. On the other hand, if the electromagnetic steel sheet 300 is too thick, the press punching operation of the electrical steel sheet 300 becomes difficult. Therefore, considering the press punching work of the electrical steel sheet 300, the thickness of the electrical steel sheet 300 is preferably 0.65 mm or less. Further, as the electromagnetic steel sheet 300 becomes thicker, the iron loss increases. Therefore, considering the iron loss characteristics of the electrical steel sheet 300, the thickness of the electrical steel sheet 300 is preferably 0.35 mm or less, more preferably 0.20 mm or 0.25 mm. In consideration of the above points, the thickness of each electrical steel sheet 300 is, for example, 0.10 mm or more and 0.65 mm or less, preferably 0.10 mm or more and 0.35 mm or less, more preferably 0.20 mm or 0.25 mm. is there. The thickness of the electrical steel sheet 300 includes the thickness of the insulating coating. The thickness of the electromagnetic steel sheet without an insulating film shall be 0.50 mm or less as described later. However, since the insulating film is thin, the thickness of the electromagnetic steel sheet including the insulating film may be 0.50 mm or less.

Each electrical steel sheet 300 constituting the stator core 111 is formed, for example, by punching a rolled plate-shaped base material (hoop). In the present embodiment, the magnetic steel sheet 300 has the best magnetic characteristics in the rolling direction RD, and the magnetic characteristics are inferior when the smaller angle of the angle formed with the rolling direction RD is around 45 ° to 60 °. .. Both the clockwise and counterclockwise directions are positive angles. Further, the electromagnetic steel sheet 300 is assumed to have a magnetic anisotropy smaller than the threshold value defined by JIS C 2552 in the circumferential direction.

As shown in FIGS. 1, 2 and 3 (a), in the present embodiment, the stator core 111 is caulked to form caulking portions 113a to 113h. The caulked portions 113a to 113h are formed, for example, as follows.
A recess having the same shape, size, and position is formed for each of the plurality of electrical steel sheets 300. When a plurality of electrical steel sheets 300 are laminated so that the plate surfaces face each other in a state where the outer edges are aligned, the recesses are fitted while being pressurized. The caulking process is performed in this way, and the caulked portions 113a to 113h are formed. In the examples shown in FIGS. 1 and 2, the shapes of the crimped portions 113a to 113h in a plan view are quadrangular. However, the shape of the crimped portion is not limited to this.

Next, an example of the position where the caulking portions 113a to 113h are formed will be described.
When a plurality of electromagnetic steel sheets laminated so that the plate surfaces face each other are fixed by caulking, the magnetic characteristics of the electromagnetic steel sheets deteriorate. The present inventor has studied performing caulking so as to suppress deterioration of the magnetic properties of such an electromagnetic steel sheet.
At that time, the present inventor has determined that the deterioration rate of the magnetic characteristics of the electromagnetic steel plate when compressive stress is applied with respect to the magnetic characteristics of the electromagnetic steel plate without stress is relatively the magnetic characteristics in the direction in which the magnetic flux flows. It is large in an excellent region (for example, a region where the magnetic flux density is relatively high for the same magnetic field strength), and is relatively poor in the magnetic characteristics in the direction in which the magnetic flux flows (for example, the magnetic flux density is relative to the same magnetic field strength). We focused on the fact that it is small in the area where it becomes low.

The deterioration rate of the magnetic characteristics of the electromagnetic steel plate when compressive stress is applied with respect to the magnetic characteristics of the electromagnetic steel plate without compressive stress is the value of the magnetic characteristics of the electromagnetic steel plate without stress and compression. It is represented by the value obtained by dividing the absolute value of the difference from the value of the magnetic characteristics of the electromagnetic steel plate when stress is applied by the value of the magnetic characteristics of the electromagnetic steel plate without stress. The value may be expressed as a percentage. In the following description, the deterioration rate of the magnetic properties of the electrical steel sheet when compressive stress is applied with respect to the magnetic properties of the electrical steel sheet not stressed is, if necessary, referred to as the deterioration rate of the magnetic properties.

When the extending direction (= radial direction) of the teeth portion 111b and the direction in which the magnetic characteristics of the electrical steel sheet 300 are excellent coincide with each other, the magnetic flux density in the teeth portion 111b becomes high. As described above, in the present embodiment, the electrical steel sheet 300 has the best magnetic properties in the rolling direction RD. Therefore, in the example shown in FIG. 1, the closer the extending direction of the teeth portion 111b is to the rolling direction RD shown by the broken line in FIG. 1, the higher the magnetic flux density in the teeth portion 111b.

Therefore, if caulking is performed in a region of the stator core 111 where the angle in the circumferential direction from the direction in which the magnetic characteristics of the electrical steel sheet 300 are excellent is small, the magnetic characteristics in the region having a high magnetic flux density will be deteriorated. .. Therefore, when caulking is performed in such a region, the deterioration rate of the magnetic characteristics becomes relatively large. On the other hand, if caulking is performed in a region of the stator core 111 where the angle in the circumferential direction from the direction in which the magnetic steel sheet 300 is excellent is large, the deterioration rate of the magnetic characteristics becomes relatively small. In the example shown in FIG. 1, when caulking is performed on a region of the stator core 111 having a large angle in the circumferential direction from the rolling direction RD shown by the broken line in FIG. 1, the deterioration rate of the magnetic characteristics becomes small.

Therefore, the caulking portion may be formed in a region where the value of the magnetic characteristic of the electromagnetic steel sheet used for the laminated core is inferior to the reference value when the laminated core is excited. Since the rotary electric machine 100 of the present embodiment is a radial gap type rotary electric machine, it is a virtual electric machine that passes through the central axis O and the position of the center of gravity of the crimped portions 113a to 113h in a direction parallel to the plate surface of the electromagnetic steel sheet 300. The crimped portions 113a to 113h may be formed so that the value of the magnetic property of the electrical steel sheet in the direction along the line is inferior to the reference value.
Here, for the reference value, for example, a sample for measurement is prepared as a measurement electromagnetic steel sheet from an electromagnetic steel sheet manufactured by the same manufacturing process as the electromagnetic steel sheet 300 used for the stator core 111, and JIS C 2550 “Electromagnetic steel strip test” is performed. It is determined based on the average value of the magnetic properties of the electrical steel sheet for measurement in a plurality of directions measured in advance by "Method" or JIS C 2556 "Method of measuring the magnetic properties of electrical steel strips by a single plate tester". The magnetic steel sheet 300 and the electrical steel sheet for measurement have the same magnetic characteristics as long as the angle formed with the rolling direction is the same. Therefore, in the following, the magnetic property of the electrical steel sheet 300 means the magnetic property measured in advance with the electrical steel sheet for measurement. The inferior value refers to a value indicating that the magnetic characteristics are inferior.

The value of the magnetic property of the electrical steel sheet in the direction parallel to the plate surface of the electrical steel sheet 300 and along the virtual line passing through the central axis O and the position of the center of gravity of the crimped portions 113a to 113h is the same as that direction. It is obtained by exciting and measuring an electromagnetic steel sheet for measurement so that the angle formed by the rolling direction is the same. Further, in the following description, the magnetic characteristics of the electrical steel sheet 300 in the direction parallel to the plate surface of the electrical steel sheet 300 and along the virtual line passing through the central axis O and the positions of the centers of gravity of the crimped portions 113a to 113h. If necessary, it is referred to as magnetic characteristics in the caulking part direction.

For example, the crimped portions 113a to 113h can be formed at positions where the value of the magnetic characteristics in the caulking portion direction is X times or less the average value of the magnetic characteristics of the electromagnetic steel sheet 300. X is a value above 0 and below 1 (0 <X <1), and for example, a value of 0.84 or more and less than 1.00 (for example, 0.985) may be adopted as the value of X. it can.
As the average value of the magnetic characteristics of the electrical steel sheet 300, for example, a value indicating that the magnetic characteristics are the best, a value indicating that the magnetic characteristics are the worst, and a value indicating that the magnetic characteristics are the best. An arithmetic mean value with at least one value between the value indicating the inferiority can be adopted.

Further, for example, the average value of the magnetic characteristics when the electromagnetic steel sheet 300 is excited with the extending direction of each tooth portion 111b as the exciting direction can be set as the average value of the magnetic characteristics of the electromagnetic steel sheet 300.
For example, assuming that the magnetic characteristics of the electromagnetic steel plate 300 are axially symmetric with respect to the direction in which the angle formed by the rolling direction RD and the rolling direction RD is 90 °, in the example shown in FIG. The smaller of the angles formed by the magnetic characteristic value and the rolling direction RD when the angle is 0 ° as the exciting direction is 6 °, 12 °, 18 °, 24 °, 30 °, 36 °. , 42 °, 48 °, 54 °, 60 °, 66 °, 72 °, 78 °, 84 °, which is twice the value of the magnetic characteristics when the direction is the excitation direction, and the rolling direction RD. The value obtained by dividing the sum and the value of the magnetic characteristics when the direction of the angle of 90 ° is the exciting direction by 16 can be used as the average value of the magnetic characteristics of the electromagnetic steel plate 300. More specifically, if the magnetic characteristic is B50 and the B50 when the angle formed by the rolling direction RD is θ (°) as the exciting direction is B _{50_θ} , then the average value B 50_ave of B50 of the electrical steel sheet 300 is _set. Is expressed by the following equation (1).
_{B 50_ave = (B 50_0 + 2B} 50_6 + 2B 50_12 + 2B 50_18 + 2B 50_24 + 2B 50_30 + 2B 50_36 + 2B 50_42 + 2B 50_48 + 2B 50_54 + 2B 50_60 + 2B 50_66 + 2B 50_72 + 2B 50_78 + 2B 50_84 + B 50_90) ÷ 16 ··· (1)

Further, the arithmetic mean value of the magnetic characteristic values when a plurality of directions including a direction different from the extending direction of the tooth portion 111b is set as the exciting direction may be used as the average value of the magnetic characteristics of the electromagnetic steel sheet.
For example, assuming that the magnetic characteristics of the electromagnetic steel plate 300 are axially symmetric when the angle formed by the rolling direction RD and the rolling direction RD is 90 °, the angle formed by the rolling direction RD is 0 °. The value of the magnetic characteristic when the direction of is the exciting direction and the value of the magnetic characteristic when the smaller angle between the rolling direction RD is 22.5 ° is twice the value of the magnetic characteristic. The smaller of the angles formed by the value and the rolling direction RD is twice the value of the magnetic characteristics when the direction of 45 ° is the exciting direction, and the smaller of the angles formed by the rolling direction RD. The value of the magnetic characteristic when the angle of 67.5 ° is the exciting direction and the value of the magnetic characteristic when the angle formed by the rolling direction RD is 90 °. The value obtained by dividing the sum of and by 8 may be used as the average value of the magnetic properties of the electromagnetic steel plate 300. More specifically, if the magnetic characteristic is B50 and the B50 when the angle formed by the rolling direction RD is θ (°) as the exciting direction is B _{50_θ} , then the average value B 50_ave of B50 of the electrical steel sheet 300 is _set. Is expressed by the following equation (2).
B _{50_ave} = (B _{50_0} + 2B _{50_22.5} + 2B _{50_45} + 2B _{50_67.5} + B _{50_90} ) ÷ 8 ・ ・ ・ (2)

In the example shown in FIG. 1, the average value of B50 of the electrical steel sheet 300 is determined based on the equation (1), and the value of the magnetic characteristic in the caulking portion direction is 0.985 times the average value of the magnetic characteristic of the electrical steel sheet 300. When the crimped portion is formed at a position as follows, it is a range determined by a virtual line that passes through the central axis O and extends in a direction parallel to the plate surface of the electrical steel sheet 300, and the virtual line and the rolling direction RD are defined. The crimped portions 113a to 113h are formed within a range in which the smaller angle of the forming angles is 45 ° or more and 90 ° or less. Specifically, there are two regions from the direction CD11 in which the smaller angle of the rolling direction RD is 45 ° to the direction CD12 in which the smaller angle of the rolling direction RD is 90 °. , CD13 in which the smaller angle of the rolling direction RD is 45 °, and CD12 in which the smaller angle of the rolling direction RD is 90 °, totaling 4 The caulked portions 113a to 113h are formed so that the center of gravity is located within the range of one region. As described above, any angle in either the clockwise or counterclockwise direction is a positive angle.

Further, in the example shown in FIG. 1, the caulked portions 113a to 113b, 113c to 113d, 113e to 113f, and 113g to 113h are evenly arranged in the circumferential direction in each region. For example, the positions of the center of gravity of the virtual line CD13 and the crimped portion 113a, the position of the center of gravity of the crimped portion 113b, and the position of the virtual line CD12 are equidistant in the circumferential direction.
Further, in the example shown in FIG. 1, the caulking portions 113a to 113h are formed in the region of the core back portion 111a among these four regions. In this way, the crimped portions 113a to 113h can be formed in the region where the magnetic flux density is lower. Further, as shown in FIG. 1, if the caulking portions 113a to 113h are formed in the region on the relatively outer peripheral side of the core back portion 111a, the caulking portions 113a to 113h can be formed in the region where the magnetic flux density is further lower. it can.
It is preferable that strain relief annealing is performed on the stator core 111 that has been caulked as described above.

<Summary>
As described above, in the present embodiment, the caulking portions 113a to 113h are formed in the region of the stator core 111 where the value of the magnetic characteristic in the caulking portion direction is inferior to the reference value. Therefore, it is possible to reduce the deterioration rate of the magnetic characteristics when compressive stress is applied by caulking. Therefore, the magnetic characteristics of the stator core 111 fixed by caulking can be improved.

<Modification example>
[Modification 1]
In the present embodiment, the case where the caulking portions 113a to 113h are formed in the region of the core back portion 111a has been described as an example. However, the crimped portion does not necessarily have to be formed on the core back portion 111a. For example, two regions from the direction CD11 where the smaller angle of the rolling direction RD is 45 ° to the direction CD12 where the smaller angle of the rolling direction RD is 90 ° and rolling. A total of four regions, from the direction CD13 where the smaller angle of the direction RD is 45 ° to the direction CD12 where the smaller angle of the rolling direction RD is 90 °. A caulking portion may be formed on the tooth portion 111b so that the center of gravity is located within the range of. Further, a caulking portion may be formed on both the core back portion 111a and the teeth portion 111b.

[Modification 2]
In the present embodiment, there are two regions from the direction CD11 in which the smaller angle formed with the rolling direction RD is 45 ° to the direction CD12 in which the smaller angle formed with the rolling direction RD is 90 °. And the total of the two regions from the direction CD13 where the smaller angle of the rolling direction RD is 45 ° to the direction CD12 where the smaller angle of the rolling direction RD is 90 °. The case where two caulking portions 113a to 113b, 113c to 113d, 113e to 113f, and 113g to 113h are formed in each of the four regions has been described as an example. However, it is sufficient that at least one caulking portion is formed in at least one of the above-mentioned four regions. For example, it is not necessary to form a caulking portion in all of the above-mentioned four regions. Further, the number of crimped portions formed in the above-mentioned four regions may be one or three or more.

[Modification 3]
The shape of the stator core is not limited to the shape shown in FIG. Specifically, the dimensions of the outer diameter and inner diameter of the stator core, the stacking thickness, the number of slots, the dimensional ratio between the circumferential direction and the radial direction of the teeth portion, the dimensional ratio in the radial direction between the teeth portion and the core back portion, etc. are desired. It can be arbitrarily designed according to the characteristics of the rotating electric machine.

[Modification example 4]
In the present embodiment, the case where the rotary electric machine 100 is a three-phase squirrel-cage induction motor has been described as an example. However, the rotary electric machine is not limited to this as illustrated below, and various known structures not not exemplified below can also be adopted.
The rotary electric machine may be an induction motor or a synchronous motor. For example, the rotary electric machine may be a winding type induction motor, a permanent magnet field type motor, an electromagnet field type motor, or a switch reluctance motor. Further, the rotary electric machine does not have to be a three-phase electric machine, and may be, for example, a single-phase electric machine. Further, the rotary electric machine may be a DC motor. Further, in the present embodiment, the electric machine has been described as an example of the rotary electric machine, but the rotary electric machine is not limited to this. For example, the rotary electric machine may be a generator.

[Modification 5]
In the present embodiment, the inner rotor type rotary electric machine has been described as an example, but the rotary electric machine is not limited to this. For example, it may be an outer rotor type rotary electric machine.
Further, in the present embodiment, the radial gap type rotary electric machine in which the stator 110 and the rotor 120 face each other with a distance in the radial direction has been described as an example, but the rotary electric machine is not limited to this. For example, it may be an axial gap type rotary electric machine in which the stator and the rotor face each other with a distance in the axial direction.
Further, in the present embodiment, the case where the laminated core is applied to the stator core has been described as an example. However, the laminated core can be applied to other than the stator core. For example, the laminated core can be applied to the rotor core. For example, a caulking portion can be formed on the rotor core of the switch reluctance motor as described in the present embodiment.

Further, as long as it is an electric device having a laminated core, the electric device is not limited to a rotary electric machine. For example, when a laminated core is used as the core of the transformer, a caulking portion can be formed on the laminated core. In this case, a caulking portion is formed in a region where the value of the magnetic characteristic of the electromagnetic steel sheet used for the laminated core is inferior to the reference value when the laminated core is excited. The reference value in this case can also be determined, for example, in the same manner as described in the present embodiment.

(Second embodiment)
Next, the second embodiment will be described. In the first embodiment, the case where the stator core 111 is formed by using the electromagnetic steel sheet 300 having the best magnetic characteristics in the rolling direction RD has been described as an example. On the other hand, in the present embodiment, a case where the stator core is formed by using an electromagnetic steel sheet having the best magnetic characteristics when the smaller angle of the rolling direction is 45 ° will be described as an example. As described above, the magnetic characteristics of the electromagnetic steel sheet used for the stator core are mainly different between the present embodiment and the first embodiment. Therefore, in the description of the present embodiment, detailed description of the same parts as those of the first embodiment will be omitted by adding the same reference numerals as those given in FIGS. 1 to 3.

FIG. 4 is a diagram showing an example of the configuration of the rotary electric machine 400. FIG. 4 is a view (plan view) of the rotary electric machine 400 as viewed from a direction parallel to the central axis O of the rotary electric machine 400, as in FIG. FIG. 5 is a diagram showing an example of the configuration of the stator core 411. FIG. 5 is a view (plan view) of the stator core 411 as viewed from a direction parallel to the central axis O of the stator core 411.

As shown in FIG. 4, the rotary electric machine 400 includes a stator 410, a rotor 120, a rotary shaft 130, and a case 140. The stator 410 and rotor 120 are housed in a case 140. The stator 410 is fixed to the case 140.
In this embodiment as well as in the first embodiment, a case where the rotor 120 employs an inner rotor type three-phase squirrel-cage induction motor in which the rotor 120 is located inside the stator 410 will be described as an example as the rotary electric machine 400.

The stator 410 includes a stator core 411 and a winding 112.
The stator core 411 includes an annular core back portion 411a and a plurality of tooth portions 411b.
In this embodiment as well, as in the first embodiment, 60 tooth portions 411b are provided so that the central angle around the central axis O is 6 ° in each tooth portion 411b. The plurality of tooth portions 411b have the same shape and the same size as each other. The winding 112 of the stator 410 is wound around the teeth portion 411b.

The I-I cross-sectional view and the II-II cross-sectional view of FIG. 5 are the same as those shown in FIGS. 3 (a) and 3 (b), respectively. Is omitted. As in the first embodiment, the rolling directions RD of the electromagnetic steel sheets constituting the stator core 411 are aligned when viewed from the stacking direction.

Each electrical steel sheet forming the stator core 411 is formed, for example, by punching a rolled plate-shaped base material (hoop). In the present embodiment, the electrical steel sheet has the best magnetic characteristics when the smaller angle formed by the rolling direction RD is 45 °, and the smaller angle formed by the rolling direction RD is 0 °. , It is assumed that the magnetic characteristics are inferior in the vicinity of 90 °. Both the clockwise and counterclockwise directions are positive angles.
In FIG. 4, the directions formed by the smaller angle with the rolling direction RD of 45 ° are ED1 and ED2. Of the angles formed by the rolling direction RD, the smaller angles are 0 ° and 90 °, respectively, which are RD and LD.

As shown in FIGS. 4 and 5, in the present embodiment, the stator core 411 is caulked to form caulking portions 413a to 413h. It is assumed that the shape and size of the crimped portions 413a to 413h of the present embodiment are the same as the shape and size of the crimped portions 113a to 113h.
Also in the present embodiment, as in the first embodiment, the crimped portions 413a to 413h are formed in the region where the value of the magnetic characteristic in the caulking portion direction is inferior to the reference value.

In the example shown in FIG. 4, the average value of B50 of the electrical steel sheet is determined based on the equation (1), and the value of the magnetic characteristic in the caulking portion direction is 0.985 times or less of the average value of the magnetic characteristic of the electrical steel sheet. When the caulking portion is formed at such a position, it is within the range determined by the virtual line extending in the direction parallel to the plate surface of the electrical steel sheet passing through the central axis O, and the angle formed by the virtual line and the rolling direction RD. The crimped portions 413a to 413h are formed in the range where the smaller angle is 0 ° or more and 25 ° or less and in the range of 65 ° or more and 90 ° or less. Specifically, the four regions from the rolling direction RD to the directions CD21 and CD22 where the smaller angle formed by the rolling direction RD is 25 °, and the smaller angle formed by the rolling direction RD are The center of gravity is located within a total of eight regions, including four regions from CD23 and CD24 in the direction of 65 ° to CD25 in the direction in which the smaller angle of the angle formed with the rolling direction RD is 90 °. , The crimped portions 413a to 413h are formed. As described above, any angle in either the clockwise or counterclockwise direction is a positive angle.

Further, in the example shown in FIG. 4, the caulked portions 413a to 413h are evenly arranged in the circumferential direction in each region. For example, the distance between the position of the center of gravity of the virtual line CD24 and the caulking portion 413a and the position of the virtual line CD25 in the circumferential direction is equal.
It should be noted that the method of determining the average value is not limited to the equation (1) as described in the first embodiment.
Further, in the example shown in FIG. 4, the caulked portions 413a to 413h are formed in the region of the core back portion 411a among these eight regions. In this way, the caulked portions 413a to 413h can be formed in the region where the magnetic flux density is lower. Further, as shown in FIG. 4, if the caulking portions 413a to 413h are formed in the region on the relatively outer peripheral side of the core back portion 411a, the caulking portions 413a to 413h can be formed in the region where the magnetic flux density is further lower. it can.
Further, it is preferable that strain relief annealing is performed on the stator core 411 that has been caulked as described above. In particular, when the stator core 411 is constructed by using the electromagnetic steel plate described in the section <Electromagnetic steel plate used for the laminated core> described later, it is necessary to perform strain relief annealing on the stator core 411.

<Summary>
As described above, the crimped portions 413a to 413h are formed in the region of the stator core 411 where the value of the magnetic characteristic in the caulking portion direction is inferior to the reference value according to the direction in which the magnetic characteristic is the best. The position can be determined. Therefore, it is possible to reduce the deterioration rate of the magnetic characteristics when compressive stress is applied by caulking while utilizing the magnetic characteristics of the magnetic steel sheet.

Also in this embodiment, various modifications described in the first embodiment can be adopted.
For example, the four regions from the rolling direction RD to the directions CD21 and CD22 where the smaller angle formed by the rolling direction RD is 25 °, and the smaller angle formed by the rolling direction RD is 65 °. Caulking portions 413a, 413b, one for each of a total of eight regions, including four regions from CD23 and CD24 to the direction CD25 where the smaller angle of the angle formed with the rolling direction RD is 90 °. The case of forming 413c, 413d, 413e, 413f, 413g, and 413h has been described as an example. However, it is sufficient that at least one caulking portion is formed in at least one of the above-mentioned eight regions. For example, it is not necessary to form a caulking portion in all of the eight regions described above. Further, the number of crimped portions formed in the above-mentioned eight regions may be two or more. Further, a caulking portion may be formed on both the core back portion 411a and the teeth portion 411b.

<Electromagnetic steel sheet used for laminated core>
An example of an electromagnetic steel plate used for the laminated core (stator core 411) of the present embodiment will be described. In the following description, the two directions in which the smaller angle of the above-mentioned rolling directions is 45 ° corresponds to the direction inclined by 45 ° from the rolling direction and the direction inclined by 135 ° from the rolling direction. To do. The 45 ° is expressed assuming that the angle in both the clockwise and counterclockwise directions has a positive value. When the clockwise direction is the negative direction and the counterclockwise direction is the positive direction, the two directions in which the smaller angle of the rolling direction is 45 ° are the angles formed with the rolling direction. Of these, the angle with the smaller absolute value is 45 ° and −45 ° in two directions. In addition, the direction inclined by θ ° from the rolling direction corresponds to the direction in which the angle formed with the rolling direction is θ °. As described above, the direction inclined by θ ° from the rolling direction and the direction formed by the angle formed with the rolling direction by θ ° have the same meaning.

First, the chemical composition of the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, and the steel material used in the manufacturing method thereof will be described. In the following description, "%", which is a unit of the content of each element contained in non-oriented electrical steel sheets or steel materials, means "mass%" unless otherwise specified. Non-oriented electrical steel sheets and steel materials, which are examples of electrical steel sheets used for laminated cores, have a chemical composition in which ferrite-austenite transformation (hereinafter, α-γ transformation) can occur, and 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, Mn, Ni, Co, Pt, Pb, Cu, Au One or more selected from the group : Total 2.50% to 5.00%, Sn: 0.000% to 0.400%, Sb: 0.000% to 0.400%, P: 0.000% to 0.400%, and One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: Containing a total of 0.0000% to 0.0100%, 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 Al content satisfies a predetermined condition described later. Examples of impurities include those contained in raw materials such as ore and scrap, and those contained in the manufacturing process.

<< C: 0.0100% or less >>
C increases iron 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 is set to 0.0100% or less. The reduction of the C content also contributes to the uniform improvement of the magnetic properties in all directions in 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 at the time of refining.

<< Si: 1.50% to 4.00% >>
Si increases the electrical resistance, reduces the eddy current loss, reduces the iron loss, increases the yield ratio, and improves the punching workability to the iron core. If the Si content is less than 1.50%, these effects cannot be sufficiently obtained. Therefore, the Si content is 1.50% or more. On the other hand, when the Si content exceeds 4.00%, the magnetic flux density decreases, the punching workability decreases due to an excessive increase in hardness, and cold rolling becomes difficult. Therefore, the Si content is set to 4.00% or less.

<< sol. Al: 0.0001% -1.0% >>
sol. Al increases electrical resistance, reduces eddy current loss, and reduces iron loss. sol. Al also contributes to the improvement of the relative magnitude of the magnetic flux density B50 with respect to the saturation magnetic flux density. Here, the magnetic flux density B50 is the magnetic flux density in a magnetic field of 5000 A / m. sol. If the Al content is less than 0.0001%, these effects cannot be sufficiently obtained. Al also has a desulfurization promoting effect in steelmaking. Therefore, sol. The Al content is 0.0001% or more. On the other hand, sol. When 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. The Al content is 1.0% or less.

<< S: 0.0100% or less >>
S is not an essential element and 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 at the time of refining.

<< N: 0.0100% or less >>
Since N deteriorates the magnetic properties as in C, the lower the N content, the better. Therefore, the N content is 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 at the time of refining.

<< One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: 2.50% to 5.00% in total >>
Since these elements are elements necessary for causing α-γ transformation, it is necessary to contain at least one of these elements in a total of 2.50% or more. On the other hand, if the total exceeds 5.00%, the cost becomes high and the magnetic flux density may decrease. Therefore, at least one of these elements should be 5.00% or less in total.

Further, it is assumed that the following conditions are further satisfied as the conditions under which the α-γ transformation can occur. That is, the Mn content (mass%) is [Mn], the Ni content (mass%) is [Ni], the Co content (mass%) is [Co], and the Pt content (mass%) is [Pt]. Pb content (mass%) is [Pb], Cu content (mass%) is [Cu], Au content (mass%) is [Au], Si content (mass%) is [Si], sol. The Al content (% by mass) was changed to [sol. Al], it is preferable that the following equation (3) is satisfied in terms of mass%.
([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au])-([Si] + [sol.Al])> 0% ... (3)

If the above equation (3) is not satisfied, the α-γ transformation does not occur, so that the magnetic flux density becomes low.

<< Sn: 0.000% to 0.400%, Sb: 0.000% to 0.400%, P: 0.000% to 0.400% >>
Sn and Sb improve the texture after cold rolling and recrystallization, and improve the magnetic flux density thereof. Therefore, these elements may be contained if necessary, but if they are contained in an excessive amount, the steel is embrittled. Therefore, both the Sn content and the Sb content are set to 0.400% or less. Further, P may be contained in order to secure the hardness of the steel sheet after recrystallization, but if it is excessively contained, it causes embrittlement of the steel. Therefore, the P content is set to 0.400% or less. In the case of imparting further effects such as magnetic properties as described above, 0.020% to 0.400% Sn, 0.020% to 0.400% Sb, and 0.020% to 0.400%. It preferably contains at least one selected from the group consisting of% P.

<< 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 >>
Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd react with S in the molten steel during casting to form sulfides, acid sulfides or both precipitates. Hereinafter, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd may be collectively referred to as "coarse precipitate-forming element". The particle size of the precipitate of the coarse precipitate-forming element is about 1 μm to 2 μm, which is much larger than the particle size of fine precipitates such as MnS, TiN, and AlN (about 100 nm). Therefore, these fine precipitates adhere to the precipitates of the coarse precipitate-forming elements, and it becomes difficult to inhibit the recrystallization and the growth of crystal grains in the intermediate annealing. In order to sufficiently obtain these effects, the total amount of these elements is preferably 0.0005% or more. However, if the total amount of these elements exceeds 0.0100%, the total amount of sulfide, acid sulfide, or both of them becomes excessive, and recrystallization and grain growth in intermediate annealing are inhibited. Therefore, the total content of the coarse precipitate-forming element is 0.0100% or less.

<< collective organization >>
Next, the texture of non-oriented electrical steel sheets, which is an example of electrical steel sheets used for laminated cores, will be described. The details of the manufacturing method will be described later, but the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, has a chemical composition that can cause α-γ transformation, and is rapidly cooled immediately after the finish rolling in hot rolling. By refining the structure, {100} crystal grains grow into a grown structure. As a result, the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, has an integrated strength of 5 to 30 in the {100} <011> direction, and a magnetic flux density B50 in the 45 ° direction with respect to the rolling direction is particularly high. It gets higher. In this way, the magnetic flux density increases in a specific direction, but an overall high magnetic flux density can be obtained on average in all directions. When the integrated strength in the {100} <011> orientation is less than 5, the integrated strength in the {111} <112> orientation, which reduces the magnetic flux density, increases, and the magnetic flux density decreases as a whole. Further, in the manufacturing method in which the integrated strength in the {100} <011> orientation exceeds 30, it is necessary to thicken the hot-rolled plate as described above, and there is a problem that the manufacturing is difficult.

The accumulation intensity of the {100} <011> orientation can be measured by an X-ray diffraction method or an electron backscatter diffraction (EBSD) method. Since the reflection angles of X-rays and electron beams from the sample differ depending on the crystal orientation, the crystal orientation intensity can be obtained from the reflection intensity or the like with reference to the random orientation sample. The integrated strength in the {100} <011> direction of the non-oriented electrical steel sheet suitable as an example of the electromagnetic steel sheet used for the laminated core is 5 to 30 in the X-ray random intensity ratio. At this time, the crystal orientation may be measured by EBSD and the value converted into the X-ray random intensity ratio may be used.

<< Thickness >>
Next, the thickness of the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, will be described. The thickness of the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, is 0.50 mm or less. If the thickness exceeds 0.50 mm, excellent high-frequency iron loss cannot be obtained. Therefore, the thickness is set to 0.50 mm or less.

<< Magnetic characteristics >>
Next, the magnetic characteristics of the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, will be described. When investigating the magnetic characteristics, the value of B50, which is the magnetic flux density of the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, is measured. In the manufactured non-oriented electrical steel sheet, one of the rolling directions and the other cannot be distinguished. Therefore, in the present embodiment, the rolling direction means both one and the other. The value of B50 (T) in the rolling direction is B50L, the value of B50 (T) in the direction tilted 45 ° from the rolling direction is B50D1, the value of B50 (T) in the direction tilted 90 ° from the rolling direction is B50C, and the rolling direction. Assuming that the value of B50 (T) in the direction inclined by 135 ° is B50D2, the anisotropy of the magnetic flux density is observed, in which B50D1 and B50D2 are the highest and B50L + B50C is the lowest. Note that (T) refers to a unit of magnetic flux density (tesla).

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 directions are 0 ° (one direction) and 180. When ° (other direction), B50D1 has a B50 value of 45 ° and 225 °, and B50D2 has a B50 value of 135 ° and 315 °. Similarly, B50L has a B50 value of 0 ° and 180 °, and B50C has a B50 value of 90 ° and 270 °. The B50 value at 45 ° and the B50 value at 225 ° exactly match, and the B50 value at 135 ° and the B50 value at 315 ° exactly match. However, B50D1 and B50D2 may not exactly match because it may not be easy to make the magnetic characteristics the same in actual manufacturing. Similarly, the B50 value at 0 ° and the B50 value at 180 ° are exactly the same, and the B50 value at 90 ° and the B50 value at 270 ° are exactly the same, while the B50L and B50C are exactly the same. It may not be. In the non-oriented electrical steel sheet which is an example of the electrical steel sheet used for the laminated core, the following equations (4) and (5) are satisfied by using the average value of B50D1 and B50D2 and the average value of B50L and B50C. ..
(B50D1 + B50D2) / 2> 1.7T ... (4)
(B50D1 + B50D2) / 2> (B50L + B50C) / 2 ... (5)

When the magnetic flux density is measured in this way, the average value of B50D1 and B50D2 becomes 1.7T or more as in Eq. (4), and anisotropy with high magnetic flux density is confirmed as in Eq. (5). ..

Further, in addition to satisfying the equation (3), it is preferable that the anisotropy of the magnetic flux density is higher than that of the equation (5) as shown in the following equation (6).
(B50D1 + B50D2) / 2> 1.1 × (B50L + B50C) / 2 ... (6)
Further, it is preferable that the anisotropy of the magnetic flux density is higher as shown in the following equation (7).
(B50D1 + B50D2) / 2> 1.2 × (B50L + B50C) / 2 ... (7)

It should be noted that the above 45 ° is a theoretical value, and it may not be easy to match it with 45 ° in actual manufacturing. Therefore, it is assumed that the value does not exactly match 45 °. This also applies to the 0 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 °.

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

<< Manufacturing method >>
Next, an example of a method for manufacturing a non-oriented electrical steel sheet, which is an example of an electromagnetic steel sheet used for a laminated core, will be described. When manufacturing a non-directional electromagnetic steel sheet, which is an example of an electromagnetic steel sheet used for a laminated core, for example, hot rolling, cold rolling (first cold rolling), intermediate annealing (first annealing), Skin pass rolling (second cold rolling), finish annealing (third annealing), strain relief annealing (second annealing), and the like are performed.

First, the steel material described above is heated and hot-rolled. The steel material is, for example, a slab manufactured by ordinary continuous casting. Rough rolling and finish rolling of hot rolling are performed at a temperature in the γ region (Ar1 or higher). That is, hot rolling is performed so that the finishing temperature of the finish rolling is Ar1 or higher. As a result, the structure is refined by transforming austenite to ferrite by subsequent cooling. When cold rolling is subsequently performed in the finely divided state, overhang recrystallization (hereinafter referred to as bulging) is likely to occur, and {100} crystal grains that are normally difficult to grow can be easily grown.

Further, when manufacturing a non-oriented electrical steel sheet which is an example of an electromagnetic steel sheet used for a laminated core, the temperature (finishing temperature) when passing through the final pass of finish rolling is set to Ar1 or higher. The crystal structure is refined by transforming austenite to ferrite. By refining the crystal structure in this way, it is possible to facilitate the occurrence of bulging through the subsequent cold rolling and intermediate annealing.

After that, the hot-rolled sheet is wound without annealing, pickled, and then cold-rolled on the hot-rolled steel sheet. In cold rolling, the rolling reduction is preferably 80% to 92%. If the reduction rate is less than 80%, bulging is less likely to occur, and if the reduction rate is more than 92%, {100} crystal grains are likely to grow due to subsequent bulging, but the hot-rolled steel sheet must be thickened and hot. Winding of rolling becomes difficult, and operation tends to become difficult.

When the cold rolling is completed, intermediate annealing is subsequently performed. When manufacturing non-oriented electrical steel sheets, which is an example of electrical steel sheets used for laminated cores, intermediate annealing is performed at a temperature that does not transform into austenite. That is, it is preferable that the intermediate annealing temperature is less than Ac1. By performing the intermediate annealing in this way, bulging occurs, and {100} crystal grains are likely to grow. The intermediate annealing time is preferably 5 to 60 seconds.

After the 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 has occurred, {100} crystal grains are further grown starting from the portion where bulging has occurred. This is because the {100} <011> crystal grains are less likely to accumulate strain due to skin pass rolling, and the {111} <112> crystal grains are more likely to accumulate strain, and the subsequent annealing results in less strain {100} < This is because the 011> crystal grains eat the {111} <112> crystal grains with the difference in strain as the driving force. This silkworm phenomenon that occurs with the strain difference as the driving force is called strain-induced grain boundary movement (hereinafter, SIBM). The rolling reduction of skin pass rolling is preferably 5% to 25%. If the reduction rate is less than 5%, the amount of strain is too small, so that strain-induced grain boundary movement (hereinafter, SIBM) does not occur in the subsequent annealing, and the {100} <011> crystal grains do not become large. On the other hand, when the reduction rate exceeds 25%, the amount of strain becomes too large, and recrystallized nucleation (hereinafter referred to as Nucleation) in which new crystal grains are generated from the {111} <112> crystal grains occurs. In this nucleation, most of the grains produced are {111} <112> crystal grains, so that the magnetic characteristics deteriorate.

After skin pass rolling, finish annealing is performed to release strain and improve workability. Similarly, the finish annealing is set to a temperature at which it does not transform into austenite, and the finish annealing temperature is set to less than Ac1. By performing finish annealing in this way, the {100} <011> crystal grains can erode the {111} <112> crystal grains, and the magnetic properties can be improved. Further, the time to reach 600 ° C. to Ac1 at the time of finish annealing is set to 1200 seconds or less. If this annealing time is too short, most of the distortion created by the skin pass remains, and warpage occurs when punching out complicated shapes. On the other hand, if the annealing time is too long, the crystal grains become too coarse, the sagging becomes large at the time of punching, and the punching accuracy cannot be obtained.

When the finish annealing is completed, a non-oriented electrical steel sheet is formed or the like in order to obtain a desired steel member. Then, in order to remove the strain and the like generated by the forming process (for example, punching) of the steel member made of the non-oriented electrical steel sheet, the steel member is subjected to strain relief annealing. In the present embodiment, in order to generate SIBM below Ac1 and allow the crystal grain size to be coarse, the strain relief annealing temperature is set to, for example, about 800 ° C., and the strain cancellation annealing time is set to about 2 hours. To do.

In the non-oriented electrical steel sheet (steel member), which is an example of the electromagnetic steel sheet used for the laminated core, among the above-mentioned manufacturing methods, the finish rolling is mainly performed with Ar1 or higher in the hot rolling process to obtain the above (3). B50 having a high formula and excellent anisotropy of the formula (4) above can be obtained. Further, in the cold rolling process, the reduction rate is set to about 85% to achieve the above-mentioned equation (5), and in the skin pass rolling process, the reduction rate is set to about 10% to obtain the better anisotropy of the above equation (6). Is obtained.

As described above, as an example of the electromagnetic steel sheet used for the laminated core, a steel member made of a non-oriented electrical steel sheet can be manufactured.

Next, the non-oriented electrical steel sheet, which is an example of the electrical steel sheet used for the laminated core, will be specifically described with reference to examples. The examples shown below are merely examples of non-oriented electrical steel sheets, and the non-oriented electrical steel sheets are not limited to the following examples.

<< First Example >>
By casting molten steel, ingots with the components shown in Table 1 below were produced. Here, the left side of the equation represents the value of the left side of the above-mentioned equation (3). Then, the produced ingot was heated to 1150 ° C. and hot-rolled, and rolled so that the plate thickness became 2.5 mm. Then, after the finish rolling was completed, it was water-cooled and the hot-rolled steel sheet was wound up. The temperature (finishing temperature) at the final pass stage of the finish rolling at this time was 830 ° C., which was higher than Ar1. No. 1 in which γ-α transformation does not occur. For 108, the finishing temperature was 850 ° C.

Next, the scale was removed from the hot-rolled steel sheet by pickling, and cold rolling was performed until the plate thickness was 1.1 times the target plate thickness (0.055 to 0.550 mm). Then, intermediate annealing was performed at 700 ° C. for 30 seconds in a non-oxidizing atmosphere. Next, a second cold rolling (skin pass rolling) was performed until the target plate thickness (0.05 to 0.50 mm) was reached. However, in order to control the strength of {100} <011>, No. In 110 to 112, the reduction rate of cold rolling was changed in the range of 80% to 92%, and the reduction rate of the second cold rolling (skin pass rolling) was changed in the range of 5 to 25%. In addition, No. In No. 113, the thickness of the hot-rolled plate was set to 7 mm, the cold rolled rolling reduction ratio was set to 95%, and skin pass rolling was not performed.

Next, in order to investigate the magnetic characteristics, after the second cold rolling (skin pass rolling), finish annealing was performed at 800 ° C. for 30 seconds to prepare a 55 mm square sample by shearing, and then at 800 ° C. for 2 hours. Strain removal annealing was performed and the magnetic flux density B50 was measured. As the measurement sample, a 55 mm square sample was taken in two directions of 0 ° and 45 ° in the rolling direction. Then, 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 set to B50L, B50D1, B50C, and B50D2, respectively.

The underline in Table 1 shows the conditions outside the scope of the present invention. No. which is an example of the invention. 101-No. 107, No. 109-No. 111, No. 114-No. In each of 116, the magnetic flux density B50 was a good value in both the 45 ° direction and the all-around average. On the other hand, No. Since 108 had a high Si concentration, the value on the left side of the equation was 0 or less, and the composition did not undergo α-γ transformation, the magnetic density B50 was low. No. which is a comparative example. In 112, the skin pass rolling ratio was lowered, so that the {100} <011> strength was less than 5, and the magnetic flux density B50 was low in each case. No. which is a comparative example. 113 has a {100} <011> strength of 30 or more, which is outside the present invention. No. Since the hot-rolled plate of 113 had a thickness of 7 mm, it had a drawback that it was difficult to operate.

<< Second Example >>
By casting molten steel, ingots with the components shown in Table 2 below were produced. Then, the produced ingot was heated to 1150 ° C. and hot-rolled, and rolled so that the plate thickness became 2.5 mm. Then, after the finish rolling was completed, it was water-cooled and the hot-rolled steel sheet was wound up. The finishing temperature at the final pass stage of the finish rolling at this time was 830 ° C., which was higher than Ar1.

Next, the scale was removed from the hot-rolled steel sheet by pickling, and cold rolling was performed until the sheet thickness became 0.385 mm. Then, intermediate annealing was performed in a non-oxidizing atmosphere, and the temperature of intermediate annealing was controlled so that the recrystallization rate was 85%. Then, the second cold rolling (skin pass rolling) was performed until the plate thickness became 0.35 mm.

Next, in order to investigate the magnetic characteristics, after the second cold rolling (skin pass rolling), finish annealing was performed at 800 ° C. for 30 seconds to prepare a 55 mm square sample by shearing, and then at 800 ° C. for 2 hours. Strain removal annealing was performed, and the magnetic flux density B50 and the iron loss W10 / 400 were measured. The magnetic flux density B50 was measured in the same procedure as in the first embodiment. On the other hand, the iron loss W10 / 400 was measured as an 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 1.0 T. The iron loss was taken as the average value of the results measured at 0 °, 45 °, 90 °, and 135 ° with respect to the rolling direction.

No. 2001-No. All 214 were invention examples, and all had good magnetic characteristics. In particular, No. 202-No. 204 is No. 201, No. No. 205-No. The magnetic flux density B50 is higher than that of 214, and No. No. 205-No. 214 is No. 2001-No. The iron loss W10 / 400 was lower than that of 204.

The non-oriented electrical steel sheet described above may not be used as the electrical steel sheet used for the laminated core (stator core 411) of the present embodiment. For example, non-oriented electrical steel sheets described in JP-A-2017-145462 can be used. However, the non-oriented electrical steel sheet has a large iron loss especially at high frequencies. Therefore, it is preferable to use the above non-oriented electrical steel sheet as the electrical steel sheet used for the laminated core (stator core 411) of the present embodiment.

(Calculation example)
Next, a calculation example will be described.
First, the electromagnetic steel sheet used for the stator core will be described. Here, the electromagnetic steel sheet 300 constituting the stator core 111 described in the first embodiment is referred to as a material A. Material A is a non-oriented electrical steel sheet having a W10 / 400 of 12.8 W / kg. W10 / 400 is an iron loss when the magnetic flux density is 1.0 T and the frequency is 400 Hz. The electromagnetic steel sheet (the electrical steel sheet described in the section <Electromagnetic steel sheet used for the laminated core>) constituting the stator core 411 described in the second embodiment is referred to as a material B. Each electromagnetic steel sheet has a thickness of 0.25 mm.
First, Table 4 shows the ratios of B50, W15 / 50, and W15 / 100 (B50 ratio, W15 / 50 ratio, W15 / 100 ratio) to the material A of the material B.

Here, B50 is the magnetic flux density when the magnetic field strength is 5000 A / m, and W15 / 100 is the iron loss when the magnetic flux density is 1.5 T and the frequency is 100 Hz. Here, the magnetic flux density and the iron loss were measured by the method described in JIS C 2556: 2015. Further, in Table 4, the average value for each angle from the rolling direction of the material B is standardized with the average value for each angle from the rolling direction of the material A as 1.000 (= from the rolling direction of the material B). The average value for each angle ÷ the average value for each angle from the rolling direction of the material A) is shown. As described above, the values in Table 4 are relative values (dimensionless quantities).

From Table 4, the B50 of the material B is 5.1% larger than the B50 of the material A. The W15 / 50 of the material B is 12.0% smaller than the W15 / 50 of the material A. The W15 / 100 of the material B is 13.5% smaller than the W15 / 100 of the material A. As described above, the material B has a larger B50 and a smaller iron loss than the material A.

FIG. 6 shows an example of the relationship between the W15 / 50 ratio and the angle from the rolling direction (FIG. 6A), and an example of the relationship between the iron loss deterioration rate and the angle from the rolling direction (FIG. 6 (FIG. 6). b)) is a figure which shows. FIG. 7 shows an example of the relationship between the W15 / 100 ratio and the angle from the rolling direction (FIG. 7 (a)), and an example of the relationship between the iron loss deterioration rate and the angle from the rolling direction (FIG. 7 (FIG. 7 (a)). b)) is a diagram showing. The magnetic properties of the material A and the material B are axisymmetric with respect to the direction in which the angle formed by the rolling direction RD and the rolling direction RD is 90 °.

In FIGS. 6A and 7A, the material A shows the W15 / 50 ratio and the W15 / 100 ratio of the unstressed material A, and the material A (30 MPa) has a compressive stress of 30 MPa. The W15 / 50 ratio and the W15 / 100 ratio of the given material A are shown. Material B shows the W15 / 50 ratio / W15 / 100 ratio of the unstressed material B, and material B (30 MPa) is the W15 / 50 ratio / W15 / of the material B to which the compressive stress of 30 MPa is applied. Shows 100 ratio. Here, FIGS. 6 (a) and 7 (a) show standardized values with the average value for each angle of the material A from the rolling direction as 1.000.

In FIGS. 6 (b) and 7 (b), the iron loss deterioration rate is the value of W15 / 100 of the unstressed electrical steel sheet and the value of W15 / 100 of the electrical steel sheet when a compressive stress of 30 MPa is applied. It is represented by the value obtained by dividing the absolute value of the difference from the value of 100 by the value of W15 / 100 of the unstressed electrical steel sheet and multiplying it by 100.

In FIGS. 6 (b) and 7 (b), the material A is a material when a stress-free material A has a W15 / 50 value and a W15 / 100 value and a compressive stress of 30 MPa is applied. The absolute value of the difference between the W15 / 50 value and W15 / 100 value of A is divided by the W15 / 50 value and W15 / 100 value of the unstressed material A and multiplied by 100. Indicates a value. Further, the material B has a W15 / 50 value / W15 / 100 value of the material B to which no stress is applied and a W15 / 50 value / W15 / 100 value of the material B when a compressive stress of 30 MPa is applied. The value obtained by dividing the absolute value of the difference from the value of W15 / 50 by the value of W15 / 50 and the value of W15 / 100 of the unstressed material B and multiplying it by 100 is shown.

As shown in FIGS. 6 (a) and 7 (a), in the material A, iron loss when excited in the rolling direction RD (the direction in which the smaller angle formed by the rolling direction RD is 0 °). Is the smallest, and the iron loss is large when the smaller angle of the angle formed with the rolling direction RD is excited in the direction of 45 ° to 60 °.

As shown in FIGS. 6 (b) and 7 (b), in the material A, the rolling direction RD (rolling direction RD) is contrary to the magnitude relationship of the iron loss shown in FIGS. 6 (a) and 7 (a). The iron loss deterioration rate is the largest when excited in the direction in which the smaller angle of the angle formed with is 0 °), and the smaller angle formed by the rolling direction RD is in the vicinity of 45 ° to 60 °. Iron loss when excited in the direction The deterioration rate of iron loss is small.

Further, as shown in FIGS. 6 (a) and 7 (a), in the material B, the iron loss is the smallest when the smaller angle of the angle formed with the rolling direction RD is excited in the direction of 45 °. , The iron loss is large when the smaller angle of the angle formed with the rolling direction RD is excited in the direction near 0 ° or 90 °.

As shown in FIGS. 6 (b) and 7 (b), in the material B, the angle formed by the rolling direction RD, contrary to the magnitude relationship of the iron loss shown in FIGS. 6 (a) and 7 (a). The iron loss deterioration rate is the largest when the smaller angle is excited in the direction of 45 °, and when the smaller angle with the rolling direction RD is excited in the direction of 0 ° or 90 °. The iron loss deterioration rate is small.

The present inventor analyzes the following three-phase squirrel-cage induction motor to analyze how the iron loss of the stator core changes depending on the position of the crimped portion of the stator core composed of the above materials A and B. As a rotating electric machine, we investigated by performing numerical analysis (computer simulation). For the numerical analysis, JMAG, a finite element method electromagnetic field analysis software manufactured by JSOL Corporation, was used.
Outer diameter of stator core: 220.0 mm
Inner diameter of stator core: 136.0 mm
Stator core height (product thickness): 100 mm
Thickness of electrical steel sheet: 0.25 mm
Number of poles: 4
Number of slots: 60
Rotor core outer diameter: 134.0 mm
Rotor core inner diameter: 35.0 mm
Rotor core height: 100 mm
Rotation speed: 3000 rpm

As an example of the invention, there are cases where the crimped portions 113a to 113h are formed at the positions shown in FIG. 1 with respect to the stator core made of the material A, and the crimped portions 413a at the positions shown with respect to the stator core made of the material B. The iron loss of the stator core in each of the cases where ~ 413h was formed was derived.

As a comparative example, there is a case where the caulking portions 813a to 813h are formed at the positions shown in FIG. 8 with respect to the stator core 811 made of the material A, and a case where the stator core 811 made of the material B is caulked at the position shown in FIG. The iron loss of the stator core 811 was derived in each of the cases where the portions 813a to 813h were formed.

FIG. 8 is a diagram showing a configuration of a rotary electric machine 800 of a comparative example. The rotary electric machine 800 shown in FIG. 8 differs from the rotary electric machines 100 and 400 shown in FIGS. 1 and 4 only in the positions of the caulked portions 813a to 813h formed on the stator 810 (stator core 811). FIG. 8 is a view (plan view) of the rotary electric machine 800 as viewed from a direction parallel to the central axis O of the rotary electric machine 800, as in FIG.
In FIG. 8, the crimped portions 813a to 813h are arranged at equal intervals of 45 ° in the circumferential direction.

Specifically, the crimped portions 813a and 813e are in a direction parallel to the plate surface of the electromagnetic steel plate (materials A and B), pass through the central axis O, and the smaller angle of the angle formed with the rolling direction RD is It is arranged so that the center of gravity is located on the virtual line 32 extending in the direction of 90 °. The caulked portions 813c and 813g are arranged so that the center of gravity is located on a virtual line extending in the rolling direction RD in a direction parallel to the plate surface of the electromagnetic steel plate (materials A and B) and passing through the central axis O. The caulked portions 813b / 813f and 813d / 813h are in a direction parallel to the plate surface of the electromagnetic steel plate (materials A and B), pass through the central axis O, and the smaller angle of the angle formed with the rolling direction RD is It is arranged so that the center of gravity is located on the virtual lines CD31 and CD33 extending in the direction of 45 °.

As described above, FIG. 4 shows the rotary electric machine 100 when the crimped portions 113a to 113h are formed at the positions shown in FIG. 1 with respect to the stator core 111 made of the material A, and the stator core 411 made of the material B. The two rotary electric machines, the rotary electric machine 400 when the caulked portions 413a to 413h are formed at the positions, and the rotary electric machine of the invention example are used. Further, the rotary electric machine 800 when the caulking portions 813a to 813h are formed at the positions shown in FIG. 8 with respect to the stator core 811 made of the material A, and the stator core 811 made of the material B are crimped at the positions shown in FIG. The two rotary electric machines, the rotary electric machine 800 when the portions 813a to 813h are formed, and the rotary electric machine of the invention example are used.

Except for the position of the crimped portion and the magnetic characteristics of the electromagnetic steel sheet constituting the stator core, the configurations of the rotary electric machines of the invention example and the comparative example are the same.
Electromagnetic field analysis is performed on the iron loss in the stator core when the rotary electric machines of the invention example and the comparative example are operated so that the rotation speed is 3000 rpm and the torque per 1 mm in the height direction is 1.0 Nm / mm. It was derived by. The results are shown in Table 5.

In Table 5, the iron loss ratio is the iron loss ratio of the stator core of the rotary electric machine 800 (comparative example of the material A) when the caulked portions 813a to 813h are formed at the positions shown in FIG. 8 with respect to the stator core 811 composed of the material A. Is standardized as 1.000 (see the column of Material A / Comparative Example in Table 5), and the value of iron loss is shown. As described above, the values in Table 5 are relative values (dimensionless quantities).

Regarding the material A, by forming the caulking portions 113a to 113h in the region where the value of the magnetic characteristic in the caulking portion direction is inferior to the reference value, the caulking portion 813a to 813h is formed in the region including the region where the caulking portion is not. The iron loss of the stator core could be reduced by 0.6% as compared with the case of forming the above (see the column of Material A / Reduction Rate in Table 5).
Further, with respect to the material B, by forming the caulking portions 413a to 413h in the region where the value of the magnetic characteristic in the caulking portion direction is inferior to the reference value, the caulking portion 813a is formed in the region including the region where the crimping portion is not. Compared with the case of forming ~ 813h, the iron loss of the stator core could be reduced by 1.2% (see the column of material B / reduction rate in Table 5).

In this way, in both the material A and the material B, the caulking portions 113a to 113h and 413a to 413h are formed in the region where the value of the magnetic characteristic in the caulking portion direction is inferior to the reference value. It can be seen that the iron loss of the stator core can be reduced as compared with the case where the crimped portions 813a to 813h are formed in the region including the region where the crimping portions are not formed. Further, it can be seen that the iron loss of the stator core can be reduced by using the material B rather than the material A. Further, comparing FIGS. 1 and 4, the caulked portions can be evenly arranged in the circumferential direction when the material B is used (FIG. 4) as compared with the case where the material A is used (FIG. 1). I understand. That is, the difference in the distance between the two caulked portions adjacent to each other in the circumferential direction can be reduced.

(Other variants)
It should be noted that 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.

100,400,800: Rotating electric machine, 110,410,810: stator, 111,411: stator core, 111a, 411a: core back part, 111b, 411b: teeth part, 113a to 113h, 413a to 413h, 813a to 813h: Caulking part, 112: Winding, 120: Rotor, 130: Rotating shaft, 140: Case, O: Central axis, RD: Rolling direction

Claims (5)

A laminated core having a plurality of electrical steel sheets laminated so that the plate surfaces face each other.
It has at least one caulked portion formed on the plurality of electromagnetic steel sheets, and has a crimped portion.
The crimped portion is formed in a region where the value of the magnetic characteristic of the electromagnetic steel sheet is inferior to the reference value.
The laminated core is characterized in that the reference value is determined based on an average value of magnetic property values of the electromagnetic steel sheet in a plurality of directions measured in advance. The electromagnetic steel sheet is
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, 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, Cd: 0.0000% to 0 in total Contains 0.0100%,
Mn content (mass%) is [Mn], Ni content (mass%) is [Ni], Co content (mass%) is [Co], Pt content (mass%) is [Pt], Pb content The amount (mass%) is [Pb], the Cu content (mass%) is [Cu], the Au content (mass%) is [Au], the Si content (mass%) is [Si], sol. The Al content (% by mass) was changed to [sol. When [Al] is set, the following formula (A) is satisfied, and
The balance has a chemical composition of Fe and impurities
B50 in the rolling direction is B50L, B50 in the direction of 90 ° to the rolling direction is B50C, and the smaller angle of the rolling direction is 45 ° in one of the two directions of B50. When B50 and B50 in the other direction are B50D1 and B50D2, respectively, the following equations (B) and (C) are satisfied, and the X-ray random intensity ratio of {100} <011> is 5 or more and less than 30. The laminated core according to claim 1, wherein the plate thickness is 0.50 mm or less.
([Mn] + [Ni] + [Co] + [Pt] + [Pb] + [Cu] + [Au])-([Si] + [sol.Al])> 0% ... (A)
(B50D1 + B50D2) / 2> 1.7T ... (B)
(B50D1 + B50D2) / 2> (B50L + B50C) / 2 ... (C) The laminated core is a rotor core or a stator core of a radial gap type rotary electric machine.
The crimped portion is a value of the magnetic characteristic of the electromagnetic steel sheet in a direction parallel to the plate surface of the electromagnetic steel sheet and along a virtual line passing through the axis of the rotor core or the stator core and the position of the center of gravity of the crimped portion. The laminated core according to claim 1 or 2, wherein is formed in a region where the value is inferior to the reference value. The electromagnetic steel sheet has the best magnetic characteristics in two directions in which the smaller angle of the angle formed by the electromagnetic steel sheet with the rolling direction is 45 °.
The crimped portion is a range determined by a virtual line extending in a direction parallel to the plate surface of the electromagnetic steel sheet through the axis of the rotor core or the stator core, and is an angle formed by the virtual line and the rolling direction of the electromagnetic steel sheet. The smaller angle is characterized in that at least one is formed in at least one of four ranges of 0 ° or more and 25 ° or less and four ranges of 65 ° or more and 90 ° or less. The laminated core according to claim 3. An electric device having the laminated core according to any one of claims 1 to 4.

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