JP2012120299A - Stator core, rotary electric machine, and manufacturing method of stator core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator core having good productivity.SOLUTION: In a stator core 1a, an adhesive agent is impregnated between layers of a plurality of laminated core sheets 4 to fix the plurality of laminated core sheets 4. The plurality of core sheet 4 includes: first core sheets 4a that are located at both end part; and second core sheets 4b that are provided between the first core sheets 4a and each include a groove 13 formed in a lamination direction. A recess 7 to which an adhesive agent is applied is formed by the first core sheets 4a and the grooves 13 of the second core sheets 4b.

Description

  The present invention relates to a stator core configured by bonding and fixing layers of a plurality of core sheets, a manufacturing method thereof, and a rotating electrical machine to which the stator core is applied.

  As a motor core used in a conventional motor, there is one in which an adhesive pocket is provided in a thin plate material such as a silicon steel plate, a predetermined amount of adhesive is deposited in the adhesive pocket, and a plurality of thin plate materials are bonded and fixed (for example, , See Patent Document 1).

JP 2009-85468 A

  In the motor core as described above, it is necessary to apply adhesive to every thin plate material that constitutes the motor core when bonding the thin plate materials to each other. There was a problem that the nature was bad.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a stator core with good productivity, a manufacturing method thereof, and a rotating electrical machine.

  A stator core according to the present invention is a stator core in which an adhesive is impregnated between layers of a plurality of laminated core sheets, and the plurality of core sheets includes a first core sheet positioned at both ends, a first core sheet, The second core sheet is provided between the core sheets and has a groove formed in the stacking direction, and the first core sheet and the groove of the second core sheet form a recess to which the adhesive is applied. It is characterized by that.

  A rotating electrical machine according to the present invention includes the stator core, a coil wound around the stator core, and a rotor that is rotatably disposed at the center of the stator core.

  Further, the stator core manufacturing method according to the present invention is a stator core manufacturing method in which an adhesive is impregnated between layers of a plurality of stacked core sheets, and is fixed in the stacking direction between the first core sheets. A step of laminating the second core sheet having the groove formed, a step of applying an adhesive to the recess formed by the groove of the first core sheet and the second core sheet, and a plurality of laminated cores And a step of impregnating an adhesive between the layers of the sheet.

  According to the stator core of the present invention, a plurality of core sheets can be bonded and fixed at a time by applying an adhesive to the recesses formed by the grooves of the first core sheet and the second core sheet. A stator core with good productivity can be obtained.

  Moreover, according to the rotating electrical machine according to the present invention, a rotating electrical machine with good productivity can be obtained by using the stator core.

  Further, according to the method for manufacturing a stator core according to the present invention, the recesses are formed by the grooves of the first core sheet and the second core sheet, and the adhesive is applied to the recesses. The sheet is bonded and fixed at a time, and a method for manufacturing a stator core with good productivity can be obtained.

It is a perspective view which shows the structure of the stator core which concerns on Embodiment 1 for implementing this invention. It is a perspective view which shows the core sheet | seat of the stator core which concerns on Embodiment 1 for implementing this invention. It is a figure which shows the manufacturing method of the stator core which concerns on Embodiment 1 for implementing this invention. It is a figure which shows the manufacturing method of the stator core which concerns on Embodiment 1 for implementing this invention. It is sectional drawing which shows the interlayer of the core sheet which concerns on Embodiment 1 for implementing this invention. It is a perspective view which shows the structure of the stator core which concerns on Embodiment 2 for implementing this invention. It is a perspective view which shows the structure of the stator core which has several recessed part which concerns on Embodiment 2 for implementing this invention. It is a perspective view which shows the structure of the stator core which concerns on Embodiment 3 for implementing this invention. It is a perspective view which shows the structure of the stator core which concerns on Embodiment 4 for implementing this invention. It is a perspective view which shows the structure of the stator core which concerns on Embodiment 5 for implementing this invention. It is a perspective view which shows the structure of the stator core which concerns on Embodiment 6 for implementing this invention. It is a perspective view which shows the structure of the stator core which concerns on Embodiment 7 for implementing this invention. It is a perspective view which shows the structure of the stator core which concerns on Embodiment 8 for implementing this invention. It is sectional drawing which shows a mode that the coil was wound by the stator core fixed by crimping. It is a perspective view which shows the structure of the rotary electric machine which concerns on Embodiment 9 for implementing this invention.

Embodiment 1 FIG.
1 and 2 show a stator core 1a according to Embodiment 1 for carrying out the present invention. FIG. 1 is a perspective view showing a structure of the stator core, and FIG. 2 is a perspective view showing a core sheet of the stator core. It is.

  As shown in FIG. 1, the stator core 1 a includes a plurality of core sheets 4 made of a substantially T-shaped electromagnetic steel plate having a yoke portion 3 and a teeth portion 2 for winding a coil protruding from the yoke portion 3. (20 sheets here) are stacked and bonded and fixed to each other.

  The plurality of core sheets 4 includes a first core sheet 4a in which an end portion 50a on the inner peripheral surface side shown in FIG. 2A, that is, an end portion on the inner peripheral surface side of the stator core 1a is formed linearly, The end portion 50b on the inner peripheral surface side shown in 2 (b), that is, the end portion on the inner peripheral surface side of the stator core 1a is configured with a second core sheet 4b formed in an arc shape. The second core sheet 4b has the same shape as the first core sheet 4b except that the shape of the end portion on the inner peripheral surface side is an arc shape. In other words, it can be said that the second core sheet 4b is formed with the arc-shaped groove 13 at the end on the inner peripheral surface side of the stator core 1a with respect to the first core sheet 4a.

  As shown in FIG. 1, the first core sheet 4a is located at both ends of the stator core 1a, and the second core sheet 4b is located between the first core sheets 4a. And the recessed part 7 is formed in the internal peripheral surface 40 of the stator core 1a by the circular-arc-shaped groove | channel 13 of this 1st core sheet | seat 4a and the 2nd core sheet | seat 4b, and all the core sheet | seats 4 are this recessed part. 7 is bonded and fixed by an adhesive impregnated between the layers of each core sheet 4. By forming the recesses 7 on the inner peripheral surface 40 of the stator core 1a in this way, the adhesive easily spreads over the entire side surface of the core sheet 4 during the impregnation of the adhesive described later.

  The concave portion 7 may have a volume larger than a volume sufficient to apply a necessary amount of adhesive so that the stator core 1a fixed in a stacked manner has an adhesive strength that does not decompose during transportation or winding. In order to obtain a high adhesive strength by reliably applying this adhesive, the adhesive is formed so as to have substantially the same volume as the total volume between the layers of the core sheet 4. The volume of the recess 7 can be changed by changing the depth of the groove 13 of the second core sheet 4b.

  Next, a method for manufacturing the stator core 1a according to the present embodiment will be described with reference to FIGS. Here, FIG. 3 is a diagram showing a step of laminating core sheets, FIG. 4 is a diagram showing a step of applying an adhesive, and FIG. 5 is a cross-sectional view showing layers between core sheets.

  First, the first core sheet 4a in which the end portion 50a on the inner peripheral surface side is formed in a straight line and the second core sheet 4b in which the end portion 50b on the inner peripheral surface side is formed in an arc shape are prepared. . The first core sheet 4a and the second core sheet 4b have the same shape except that the shape of the end portion on the inner peripheral surface side is different. That is, it can be said that the second core sheet 4b has an arc-shaped groove 13 formed at the end on the inner peripheral surface side with respect to the first core sheet 4a.

  Next, the second core sheet 4b is laminated between the first core sheets 4a. Then, for example, as shown in FIG. 3 (a), the core sheet 4 is accurately aligned by the alignment jig 11, and the alignment jig 11 is removed so as not to break the alignment, and as shown in FIG. 3 (b). The fixing jigs 15 are fastened with screws to fix them in the stacking direction. Thereby, the recessed part 7 is formed with the groove | channel 13 of the 1st core sheet 4a and the 2nd core sheet 4b. Since the shape accuracy of the stator core 1a to be manufactured depends largely on the accuracy of the jig to be aligned, it is desirable that the shape accuracy of the alignment jig 11 satisfies the dimensional accuracy required for the stator core 1a.

  Next, as shown in FIG. 4 (a), the core sheet 4 is installed so that the concave portion 7 faces vertically upward, and as shown in FIG. 4 (b), for example, Loctite LO-210 An adhesive 14 having a low viscosity and anaerobic properties such as (registered trademark, manufactured by Henkel) is applied. By using the anaerobic adhesive 14 in this way, the adhesive 14 exposed on the surface volatilizes and disappears, and the adhesive remains in unnecessary portions, resulting in deterioration of motor characteristics and shape accuracy. This can be prevented. In FIG. 4, the fixing jig 15 is not shown for convenience of drawing.

  Moreover, it is desirable that the adhesive 14 has a viscosity that can sufficiently impregnate the gaps between the core sheets 4 that are 1 to 5 μm. Although an anaerobic adhesive is used here, an anaerobic adhesive may not be used when there is no problem with deterioration of motor characteristics and shape accuracy caused by the remaining adhesive.

  Next, the adhesive 14 is impregnated between the layers of the core sheet 4. The plurality of core sheets 4 fixed in the stacking direction by the fixing jig 15 have gaps 10 of about 1 to 5 μm between the layers as shown in FIG. Each gap 10 is uniformly impregnated and spreads over the entire side surface of each core sheet 4. In this way, a plurality of core sheets 4 can be bonded at a time. Here, since the adhesive 14 is uniformly impregnated into each interlayer 10, all the core sheets 4 are bonded with uniform strength. Moreover, since the recessed part 7 is formed in the inner peripheral surface, the adhesive tends to spread over the entire side surface of the core sheet 4. Furthermore, since the whole side surface of the core sheet 4 is adhered, high adhesive strength can be obtained.

  The adhesive 14 impregnated in the gap 10 is slightly exposed from the end portion of the core sheet, so it is important that the adhesive 14 is not adhered in a state where a member such as a jig is in contact. Moreover, the adhesive 14 does not spill out from the concave portion 7 unless the adhesive 14 is applied so as to overflow, and the adhesive 14 does not flow out to an unnecessary portion in terms of motor characteristics and shape accuracy.

  Next, after sufficiently impregnating the adhesive 14, the core sheets 4 are bonded and fixed to each other by heating and curing the adhesive 14 using a drying furnace. Finally, the stator core 1a according to the present embodiment is obtained by taking it out from the fixing jig 15.

  According to the present embodiment, since the recesses 7 are formed by the grooves 13 of the first core sheet 4a and the second core sheet 4b, a plurality of core sheets 4 are formed by applying an adhesive to the recesses 7. The stator core can be bonded and fixed at a time, and a highly productive stator core can be obtained.

  In addition, since the concave portion 7 is provided on the inner peripheral surface 40 of the stator core, the adhesive 14 easily spreads over the entire side surface of the core sheet 4, and the entire side surface of the core sheet 4 is bonded and fixed, so that high adhesive strength is obtained.

  Moreover, since the 1st core sheet | seat 4a whose inner peripheral surface side edge part 50a is linear, and the 2nd core sheet | seat 4b whose inner peripheral surface side edge part 50b is circular arc shape were used, it is complicated. The concave portion 7 can be formed without using a core sheet having a shape.

  Moreover, since the recessed part 7 was formed with the groove | channel of the 1st core sheet 4a and the 2nd core sheet 4b, and the adhesive agent 14 was apply | coated to this recessed part 7, the several core sheet 4 adheres and fixes at once. Thus, a method for manufacturing a stator core with good productivity can be obtained.

  In the present embodiment, a stator core in which 20 core sheets 4 are laminated and bonded and fixed is illustrated. However, as long as there are three or more core sheets 4, the core can be arbitrarily changed according to the application. .

Embodiment 2. FIG.
6 and 7 show a stator core 1b according to Embodiment 2 for carrying out the present invention. FIG. 6 is a perspective view showing a structure of the stator core 1b. FIG. 7 shows a stator core 1b having a plurality of recesses. FIG.

  In the first embodiment, the first core sheet 4a in which the end portion 50a on the inner peripheral surface side is formed in a straight line and the second core sheet 4b in which the end portion 50b on the inner peripheral surface side is formed in an arc shape. As shown in FIG. 6, the first core sheet 4a in which the end portion 50a on the inner peripheral surface side is formed in an arc shape and the end portion on the inner peripheral surface side are shown. The concave portion 7 may be formed by using the second core sheet 4b in which the groove 13 is formed in the end portion 50b, while 50b is formed in an arc shape. In FIG. 6A, the recess 7 is formed by using the second core sheet 4b in which the semicircular groove 13 is formed. However, as shown in FIG. 6B, the rectangular groove 13 is formed. You may form the recessed part 7 using the 2nd core sheet 4b in which was formed. Even in such a configuration, the volume of the recess 7 can be changed by changing the depth of the groove 13. Moreover, if comprised in these, a stator core will be pseudo-multiple slots and a cogging torque can be reduced. In addition, although the semicircle and the rectangular groove | channel 13 are illustrated here, the shape of the groove | channel 13 is not limited to these. Moreover, you may form so that the groove | channel 13 may incline toward the lamination direction.

In addition, as shown in FIG. 7, a plurality of recesses 7 may be formed using a second core sheet 4 b having a plurality of grooves 13. By forming in this way, the effect of reducing the cogging torque is increased.
Since the other configuration and manufacturing method of stator core 1b are the same as those of the first embodiment, the description thereof is omitted.

  According to the present embodiment, the first core sheet 4a in which the end portion 50a on the inner peripheral surface side is formed in an arc shape, and the end portion 50b on the inner peripheral surface side is formed in an arc shape. Since the concave portion 7 is formed by the second core sheet 4b in which the groove 13 is formed in the end portion 50b, the plurality of core sheets 4 are once attached by applying an adhesive to the concave portion 7 as in the first embodiment. A stator core with high productivity can be obtained.

Embodiment 3 FIG.
FIG. 8 is a perspective view showing a stator core 1c according to Embodiment 3 for carrying out the present invention. In each of the above embodiments, the configuration in which the concave portion 7 is formed on the inner peripheral surface 40 of the stator core is shown. However, as shown in FIG. 8, the first core in which the outer peripheral surface end 51a is formed in an arc shape. The outer peripheral surface 41 of the stator core is formed by the sheet 4a and the second core sheet 4b in which the end 51b on the outer peripheral surface side is formed in an arc shape and the rectangular groove 13 is formed in the end 51b. The recess 7 may be formed. Even when the concave portion 7 is formed on the outer peripheral surface 41, the adhesive easily spreads over the entire side surface of the core sheet 4 when impregnated with the adhesive, as in the case described in the above embodiments. Moreover, since the recessed part 7 was formed in the outer peripheral surface 41 which a magnetic flux does not pass, there is no deterioration of the motor characteristic by forming the recessed part 7. FIG. Since other configurations and manufacturing methods are the same as those in the first embodiment, description thereof is omitted. Moreover, in this Embodiment, although what formed the recessed part 7 using the 2nd core sheet | seat 4b in which the rectangular groove | channel 13 was formed is illustrated, the shape of the groove | channel 13 is not limited to this. Absent.

  According to the present embodiment, the first core sheet 4a in which the outer peripheral surface side end portion 51a is formed in an arc shape, and the outer peripheral surface side end portion 51b are formed in an arc shape, and this end portion Since the recess 7 is formed in the outer peripheral surface 41 of the stator core by the groove 13 of the second core sheet 4b in which the groove 13 is formed in 51b, by applying an adhesive to the recess 7 as in the first embodiment. A plurality of core sheets 4 can be bonded at a time, and a stator core with good productivity can be obtained.

Embodiment 4 FIG.
FIG. 9 is a perspective view showing a stator core 1d according to Embodiment 4 for carrying out the present invention. In the second embodiment, the configuration in which the concave portion 7 is formed on the inner peripheral surface of the stator core is shown. However, as shown in FIG. 9, the concave portion 7 may be formed on the side surface 42 of the stator core. In FIG. 9A, the concave portion 7 is formed by using the first core sheet 4a and the second core sheet 4b in which the tooth portion 2 is narrower than the first core sheet 4a. The narrow portion of the second core sheet 4 b corresponds to the groove 13. Moreover, in FIG.9 (b), the recessed part 7 is formed using the 1st core sheet 4a and the 2nd core sheet 4b by which the semicircle-shaped groove | channel 13 was formed in the side surface. Even if comprised in this way, the several core sheet | seat 4 can be adhere | attached at once by apply | coating an adhesive agent to the recessed part 7, and a stator core with good productivity can be obtained.
In the configuration of FIG. 9B, the shape of the groove 13 is not limited to a semicircular shape, and may be a rectangular shape or the like.

Embodiment 5 FIG.
FIG. 10 is a perspective view showing a stator core 1e according to Embodiment 5 for carrying out the present invention. In order to change the volume of the concave portion 7 in the first embodiment, the stator core 1e is configured such that the first core sheet 4a is also arranged at portions other than both ends of the stator core as shown in FIG. 10 (a). It is. Here, an example is shown in which the first core sheet 4a is also arranged on the fifth, tenth, and fifteenth sheets. Moreover, as shown in FIG.10 (b), even if it forms the edge part 50a by the side of the internal peripheral surface of the 1st core sheet 4a in substantially trapezoid shape, the volume of the recessed part 7 can be changed. By configuring as described above, the volume of the concave portion 7 can be easily changed, and the volume of the concave portion 7 is formed so as to be substantially the same as the total volume between the layers of each core sheet 4, and a necessary amount of adhesion is achieved. The agent can be reliably applied.

Embodiment 6 FIG.
FIG. 11 is a perspective view showing a stator core according to Embodiment 6 of the present invention. In each of the above-described embodiments, the stator core is configured by using the substantially T-shaped core sheet 4 having the yoke portion 3 and the teeth portion 2 protruding from the yoke portion 3, but FIG. ), The stator core 1f may be configured by using a core sheet 4 having a plurality of yoke portions 3 connected via the bent portions 16 and a plurality of teeth portions 2 protruding from the yoke portions 3. Good. Even in such a configuration, the same effect as described above can be obtained.
In addition, the stator core 1f obtained by applying an adhesive and fixing the core sheets to each other with the concave portion 7 vertically upward is bent at the bent portion 16 and the coil 23 is wound around each tooth portion 2. Thus, the stator of the rotating electrical machine as shown in FIG. 11B is obtained. Moreover, in this Embodiment, although the structure which provides the recessed part 7 in the internal peripheral surface 40 of a stator core is illustrated, the recessed part 7 can form any of said each embodiment.

Embodiment 7 FIG.
FIG. 12 is a perspective view showing a stator core according to Embodiment 7 for carrying out the present invention. In the first to fifth embodiments, the stator core is configured by using the substantially T-shaped core sheet 4 having the yoke 3 and the teeth portion 2 protruding from the yoke portion 3, but as shown in FIG. Alternatively, the stator core 1g may be configured by using a core sheet 4 having a ring-shaped yoke portion 3 and a plurality of teeth portions 2 projecting radially from the yoke portion 3. Even in such a configuration, the same effect as described above can be obtained. In addition, in this Embodiment, although the structure which provides the recessed part 7 in the outer peripheral surface 41 of a stator core is illustrated, the recessed part 7 can form any of Embodiment 1-5.

Embodiment 8 FIG.
FIG. 13 is a perspective view showing a configuration of a stator core according to Embodiment 8 for carrying out the present invention. In the stator core 1h according to the present embodiment, the core sheets 4 are fixed by caulking between the core sheets 4 at the position of the caulking portion 19, and the core sheets 4 are bonded and fixed by an adhesive impregnated between the layers. Has been. Other configurations are the same as those of the first embodiment.
Further, the manufacturing method of the stator core 1h is the same as that of the first embodiment except that when the first core sheet 4a and the second core sheet 4b are stacked, they are fixed by stacking and stacked. Since there is, explanation is omitted.

  Next, a comparison between the case where the coil 23 is wound around the stator core 1h in the present embodiment and the case where the coil 23 is wound around the conventional stator core 30 will be described with reference to FIG. FIG. 14 is a cross-sectional view showing a state where a coil is wound around a stator core fixed by caulking, FIG. 14A is a view showing a state where a coil is wound around a conventional stator core, and FIG. It is a figure which shows a mode that the coil was wound around the stator core which concerns on this Embodiment.

  In the conventional caulking fixed stator core 30, as shown in FIG. 14 (a), when the coil 23 is wound around the tooth portion, the outer periphery of the stator core 30 is wound in an arcuate shape in the stacking direction. To do. In this tightening, since the caulking and fixing core sheet 4 has a gap 10 of about 3 to 10 μm, when the coil 23 is wound, the gap 10 between the core sheets in the teeth portion is narrowed by the coil tension. This occurs when the difference in the gap 10 increases between the inner peripheral portion and the outer peripheral portion of the stator core 30. Since the shape accuracy of the stator core deteriorates due to the occurrence of winding tightening, the smaller the winding tightening, the better.

  On the other hand, in the stator core according to the present embodiment, as shown in FIG. 14B, the gap 10 is impregnated with the adhesive 14 and the core sheets 4 are bonded and fixed, so that the rigidity of the stator core 1h increases. The difference in the gap 10 between the core sheets at the inner and outer circumferences of the stator core 1h due to the coil tension when the coil 23 is wound can be suppressed. As a result, it is possible to obtain a punched stator core 1h with less winding tightening.

  In the present embodiment, the stator core 1a shown in the first embodiment is caulked and fixed, but the same effect can be obtained by applying to any of the stator cores of the above-described embodiments.

Embodiment 9 FIG.
FIG. 15 is a schematic diagram showing a rotating electrical machine 100 according to Embodiment 9 for carrying out the present invention. As shown in FIG. 15, the rotating electrical machine 100 includes a mold frame 22 having brackets 21 at both ends, a stator core 1a shown in Embodiment 1 sealed and cured in the mold frame 22, and the stator core 1a. A coil 23 wound around the teeth portion of the rotor, a rotor 27 having a shaft 26 supported by the mold frame 22 via a bearing 25, and a magnet 26 disposed rotatably at the center of the stator core 1a, and the rotor 27 And a detector 28 for detecting the rotation of. In addition, although the rotary electric machine 100 provided with the stator core 1a of Embodiment 1 was shown here, it replaces with this and any stator core of said each embodiment can be used.

  According to the present embodiment, since the stator core 1a according to the first embodiment is used, the rotating electrical machine 100 with high productivity can be obtained.

  In each of the above embodiments, the configuration in which the concave portion 7 is provided on any one of the inner peripheral surface, the outer peripheral surface, and the side surface of the stator core is shown, but the stator core is configured by providing the concave portions on two or more surfaces. May be. By comprising in this way, higher adhesive strength can be obtained. The configurations described in the above embodiments can be combined with each other.

1a, 1b, 1c, 1d, 1f, 1g, 1h Stator core 2 Teeth portion 3 Yoke portion 4 Core sheet 4a First core sheet 4b Second core sheet 7 Recess 10 Clearance 13 Groove 14 Adhesive 16 Bending portion 40 Stator core Inner peripheral surface 41 Outer peripheral surface of stator core 42 Side surfaces of stator core 50a, 50b End portions on inner peripheral surface side 51a, 51b End portions on outer peripheral surface side 23 Coil 27 Rotor 100 Rotating electric machine

Claims (14)

In a stator core that is bonded and fixed by impregnating an adhesive between layers of a plurality of laminated core sheets,
The plurality of core sheets are composed of a first core sheet positioned at both ends, and a second core sheet provided between the first core sheets and having grooves formed in the stacking direction,
A stator core in which a concave portion to which the adhesive is applied is formed by a groove of the first core sheet and the second core sheet.   2. The stator core according to claim 1, wherein each of the first and second core sheets has a substantially T shape having a yoke portion and a teeth portion protruding from the yoke portion.   The said 1st and 2nd core sheet | seat has the some yoke part connected through the site | part which can be bent, and the some teeth part which each protruded from each yoke part, It is characterized by the above-mentioned. The stator core described.   2. The stator core according to claim 1, wherein each of the first and second core sheets includes an annular yoke portion and a plurality of teeth portions projecting radially from the yoke portion.   The stator core according to any one of claims 1 to 4, wherein the concave portion is provided on an inner circumferential surface of the stator core.   The stator core according to any one of claims 1 to 4, wherein the concave portion is provided on an outer peripheral surface of the stator core.   The stator core according to claim 1, wherein the concave portion is provided on a side surface of the stator core. An end portion on the inner peripheral surface side of the first core sheet is formed linearly,
The stator core according to claim 5, wherein an end portion of the second core sheet on the inner peripheral surface side is formed in an arc shape.   End portions on the inner peripheral surface side of the first and second core sheets are each formed in an arc shape, and a groove is formed on an end portion on the inner peripheral surface side of the second core sheet. The stator core according to claim 5.   The end portions on the outer peripheral surface side of the first and second core sheets are each formed in an arc shape, and the groove is formed on the end portion on the outer peripheral surface side of the second core sheet. The stator core according to claim 6.   11. The stator core according to claim 1, wherein a volume of the concave portion is substantially the same as a total volume between layers of the plurality of core sheets.   The stator core according to any one of claims 1 to 11, wherein the plurality of core sheets are fixed by caulking. The stator core according to any one of claims 1 to 12,
A coil wound around the stator core;
A rotating electrical machine comprising: a rotor disposed rotatably at a central portion of the stator core. In the method of manufacturing a stator core in which an adhesive is impregnated between layers of a plurality of laminated core sheets and bonded and fixed,
Laminating a second core sheet having grooves formed in the laminating direction between the first core sheets;
Applying the adhesive to a recess formed by a groove of the first core sheet and the second core sheet;
And a step of impregnating the adhesive between layers of the laminated core sheets.

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