JP2010148329A - Stator core structure of rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an excellent increase effect or the like of a magnetic flux density by putting a stator core in a proper stress state with a simple configuration. <P>SOLUTION: The stator core 4 having an annular shape is composed by installing a prescribed number of blocks 9, which are composed by laminating a plurality of split pieces 8 in a rotor rotating shaft direction, side by side toward a peripheral direction, and the stator core 4 is a stator core structure of a rotating electric machine which is brought into contact with and held by a cylindrically shaped case. The split pieces 8 include yokes 10 and teeth 11 which project toward a rotor axis direction from an inner periphery face and have a mating surface which is inclined so as to form inward-expanding gaps 14 with the split pieces 8 adjacent to each other in a circumferential direction. When the stator core 4 is held by the cylindrically shaped case, an interference of the stator core 4 and a tilt angle of the mating surface are set so as to firmly stick the adjacent blocks 9 according to a clamping force given to the stator core 4 from the cylindrically shaped case. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a stator core structure of a rotating electrical machine in which an annular stator core is configured by arranging a predetermined number of block bodies formed by laminating a plurality of divided pieces in the rotor rotational axis direction in the circumferential direction. .

  The rotating electrical machine composed of the electric motor or the generator converts electrical energy into rotational force or converts rotational force into electrical energy, and contributes to energy saving by effectively improving the conversion efficiency. It is hoped that. For example, in an electric vehicle using an electric motor as a drive source or a hybrid vehicle that obtains driving force by combining an engine and an electric motor, conversion of electric energy and rotational force in a wide load region from light load region to high load region There is a need to save electrical energy and fuel by improving efficiency.

  And for the purpose of improving the conversion efficiency between the electric energy and the rotational force of the rotating electrical machine, a unidirectional electrical steel sheet having a unidirectional easy axis, and a bidirectional direction having two easy magnetization axes perpendicular to each other Either a magnetic steel sheet or a non-oriented electrical steel sheet whose easy axis is not oriented in a specific direction is punched and formed into a predetermined shape, and a plurality of the extracted steel sheets are stacked and integrated. Thus, the stator core is formed.

  When the stator core is formed using the unidirectional electrical steel sheet or the bi-directional electrical steel sheet having excellent magnetic characteristics in a specific direction, for example, excellent magnetic characteristics are exhibited in the teeth portion of the stator core. By arranging the direction in the radial direction and arranging the direction in which excellent magnetic properties are exhibited in the yoke portion in the circumferential direction, it is possible to effectively reduce the iron loss of the stator core. There is an advantage that heat generation can be suppressed and torque can be improved. However, since the unidirectional electrical steel sheet or the bi-directional electrical steel sheet is more expensive than the non-oriented electrical steel sheet, it effectively improves the magnetic properties of the stator core formed by the non-oriented electrical steel sheet, or It is desirable to be able to effectively prevent deterioration of magnetic characteristics when a stator core made of a non-oriented electrical steel sheet is assembled to a case of a rotating electrical machine.

  For example, as shown in Patent Document 1 below, a split yoke portion divided by a split surface that splits the annular ring in the circumferential direction is provided, and the ring yoke portion is configured by connecting the split yoke portions to each other. In the split stator core, at least one of the connecting portions of the split yoke portion includes a notch portion having an end surface that is recessed from the split surface toward the inner diameter direction of the ring, and an end surface of the split surface toward the outer shape of the ring shape. It is carried out to make it the structure provided with the projection part. According to this structure, only the outer peripheral portion of the divided surface formed on the end surface of each divided yoke portion is brought into a pressure contact state, and the other portions are separated from each other, whereby the stator core yoke is shrink-fitted into the core case. It is supposed that the residual compressive stress in the main magnetic flux region formed in the part from the inner peripheral side of the part to the tooth part can be made zero.

In addition, as shown in Patent Document 2 below, in the electric motor including a stator core (stator) having a plurality of teeth portions in the circumferential direction and a cylindrical case (outer frame) that contacts and fixes the stator core, the teeth The outer periphery of the stator core where the root is located is fixed in contact with the cylindrical case, and the stress in the vicinity of the outer periphery of the stator core is relieved between the tooth root and the outer periphery of the stator core fixed in contact with the cylindrical case. By providing a gap for the purpose of preventing the compression stress from being generated when the outer periphery of the stator core is contact-fixed to the cylindrical case, it is possible to reduce the deterioration of magnetic characteristics as much as possible. ing.
JP 2005-51941 A JP 2005-354870 A

  Considering the flow of magnetic flux in the stator core, a main magnetic flux flow is formed from the tip portion of the teeth portion facing the rotor disposed in the stator core toward the outer side (outer diameter direction), A magnetic flux flow is formed in the yoke portion of the stator core so as to flow into the adjacent tooth portion through the inner peripheral side. For this reason, as shown in Patent Document 1, when the inner circumferential side portion of each divided yoke portion is separated from the adjacent divided yoke portion, the flow of magnetic flux to the adjacent divided yoke portions is It should be directed to the contact portion, that is, the outer peripheral side of the divided yoke portion. However, the contact portion formed of the protrusion formed on the split surface of the split yoke portion has a problem that the width dimension is narrow and the flow of magnetic flux is greatly hindered because it is in a compressed state as described above. . Therefore, as disclosed in Patent Document 1, the residual compressive stress in the main magnetic flux region formed in the portion from the inner peripheral side of the yoke portion of the stator core to the teeth portion can be reduced to zero. There is a problem that the flow of magnetic flux is hindered in the separated portion, and the motor efficiency is greatly reduced.

  Further, the invention disclosed in Patent Document 2 is intended to alleviate the residual compressive stress in the stator core, and this compressive stress is set to 0 or when the tensile stress is applied to the inner peripheral portion of the stator core. Such a remarkable iron loss reduction effect could not be obtained, and there was room for improvement in this respect.

  The present invention has been made in view of the above problems, and an object thereof is to obtain an excellent effect of reducing iron loss and increasing magnetic flux density by setting a stator core to an appropriate stress state with a simple configuration. It is said.

  According to the first aspect of the present invention, an annular stator core is formed by arranging a predetermined number of block bodies formed by laminating a plurality of divided pieces in the rotor rotation axis direction, and an outer peripheral surface of the stator core. Is a stator core structure of a rotating electrical machine configured to be held in contact with an inner peripheral surface of a cylindrical case, and the divided piece includes a yoke portion and an inner peripheral surface from the inner peripheral surface toward the rotor axial direction. A projecting tooth portion, and having a mating surface inclined so as to form an inwardly extending gap between the circumferentially adjacent divided pieces, and holding the stator core in the cylindrical case In addition, according to the tightening force applied to the stator core from the cylindrical case, the tightening allowance of the stator core and the adjacent block bodies are in close contact with each other. In which the inclination angle of the mating surface is set.

  According to a second aspect of the present invention, in the stator core structure of the rotating electrical machine according to the first aspect, the inner peripheral side of the yoke portion according to the fastening force of the stator core applied when the stator core is held in the cylindrical case. The stator core tightening margin and the inclination angle of the mating surface are set such that a region where the compressive stress is 0 or a tensile stress is formed in the portion.

  According to a third aspect of the present invention, in the stator core structure of the rotating electric machine according to the first or second aspect, a protruding portion that protrudes in a direction opposite to the teeth portion from the yoke portion is formed on the outer peripheral surface of the divided piece. When the stator core is held in the cylindrical case, the projection is pressed against the inner peripheral surface of the cylindrical case so that a clamping force is applied to the stator core.

  In the invention according to claim 1, since the annular stator core is configured by arranging a predetermined number of blocks formed by laminating a plurality of divided pieces in the rotor rotation axis direction in the circumferential direction, a plurality of the blanks punched in an annular shape As compared with the case where the stator core is configured by laminating the electromagnetic steel sheets, there is an advantage that the manufacturing cost can be reduced by suppressing waste of materials. Then, the adjacent block bodies can be brought into close contact with each other, for example, by inserting an annular stator core having a predetermined number of blocks arranged in the circumferential direction into the cylindrical case and shrink fitting. There is an advantage that it is possible to effectively prevent a decrease in magnetic properties due to the formation of a gap between adjacent block bodies.

  In the invention according to claim 2, the compressive stress is 0 or the tensile stress is applied to the inner peripheral side portion of the yoke portion in accordance with the fastening force of the stator core applied when the stator core is held in the cylindrical case. Since the inclination angle of each mating surface is set so that a region is formed, a portion that has a great influence on the magnetic characteristics of a stator core made of a non-oriented electrical steel sheet or the like, that is, the inner peripheral side portion of the yoke portion By effectively preventing the problem that the flow of magnetic flux is greatly hindered, there is an advantage that excellent magnetic characteristics can be obtained.

  In the invention according to claim 3, since the projecting portion provided on the outer peripheral surface of the divided piece is configured to be pressed against the inner peripheral surface of the cylindrical case, a predetermined tightening force is applied to the stator core. Accordingly, a high compressive stress is applied to the outer peripheral side portion of the yoke portion located in the vicinity of the base end portion of the protruding portion, and a corresponding tensile stress is applied to the inner peripheral side portion of the yoke portion. Can do. Therefore, it is possible to effectively prevent the problem that the flow of magnetic flux is greatly obstructed in the part that has a great influence on the magnetic characteristic of the stator core, that is, the inner peripheral side part of the yoke part. There is an advantage that can be obtained.

  1 to 3 show an embodiment of a rotating electrical machine according to the present invention. This rotating electrical machine has a cylindrical case 1 made of aluminum alloy, cover members 2 and 3 installed so as to cover both ends of the rotor rotational axis, and an outer peripheral surface in contact with an inner peripheral surface of the cylindrical case 1. The stator core (stator) 4 held in this manner and the rotor (rotor) 5 disposed in the stator core 4 are provided. The rotor 5 includes a rotor rotating shaft 6 rotatably supported by bearings 2 a and 3 a disposed on the cover members 2 and 3, and a permanent magnet installed to rotate integrally with the rotor rotating shaft 6. 7.

  The stator core 4 is composed of a predetermined number (eight in the present embodiment) of block bodies 9 formed by laminating a plurality of divided pieces 8 in the rotor rotation axis direction, and these block bodies 9 are also provided in the circumferential direction. As a result, an annular shape is formed. The divided piece 8 includes an arcuate yoke portion (body portion) 10 formed by punching out an electromagnetic steel sheet, and a teeth portion that protrudes in the rotor axial direction from the inner circumferential surface located in the circumferential center portion thereof. (Tooth part) 11. A coil (armature winding) 12 is wound around the tooth portion 7, and the outer peripheral surface of the yoke portion 10 is connected to the teeth portion 11 and the teeth portion 11 from the center in the circumferential direction as shown in FIG. A projecting portion 13 having a predetermined height projecting in the opposite direction (outer peripheral direction) is provided.

  In addition, an inclined mating surface 15 is formed at the circumferential end of each of the divided pieces 8 so as to form an inwardly extending gap 14 between adjacent divided pieces 8. The inclination angle θ of the mating surface 15 is determined when the stator core 4 is held in pressure contact with the cylindrical case 1 as will be described later, specifically, the outer peripheral surface of the divided piece 8, specifically the protrusion 13. The mating surfaces 15 of the adjacent block bodies 9 are in close contact with each other according to the tightening allowance of the stator core 4 corresponding to the tightening force applied to the stator core 4 by pressing the front end surface to the inner peripheral surface of the cylindrical case 1. It is set to be in the state.

  In order to manufacture the rotating electric machine, first, a split piece 8 having the yoke part 10, the tooth part 11 and the protruding part 13 is formed by punching out a magnetic steel sheet having a thickness of about 0.1 to 1.0 mm. . Next, the divided pieces 8 are stacked one by one. At that time, crimping is performed by press working so that a minute recess is formed at a predetermined position on the upper surface, and a minute protrusion is formed on the lower surface (back surface) of the minute recess, and then temporary bonding is performed. Then, after repeating this until a predetermined number of sheets is reached, a predetermined number of block bodies 9 in which a plurality of divided pieces 8 are laminated and integrated in the direction of the rotor rotation axis are formed by welding the outer peripheral surface portion or the like. .

  Further, the cylindrical case 1 having an inner diameter slightly smaller than the outer diameter of the stator core 4 composed of the predetermined number of block bodies 9 is formed. Next, the inner diameter of the cylindrical case 1 is made larger than the outer diameter of the stator core 4 by shrink fitting that heats and heat expands the cylindrical case 1 or cools and shrinks the block bodies 9. In this state, the stator core 4 is inserted and installed in the cylindrical case 1. When the temperature of the cylindrical case 1 thermally expanded as described above decreases according to the room temperature, or when the temperature of the thermally contracted stator core 4 increases according to the room temperature, the inner diameter of the cylindrical case 1 becomes the stator core 4. The stator core 4 is held by the cylindrical case 1 in a state where the inner peripheral surface of the cylindrical case 1 is in pressure contact with the protruding portion 13 of the divided piece 8. In addition, by pressing the stator core 4 into the cylindrical case 1, the stator core 4 is held in the cylindrical case 1 in a state where the inner peripheral surface of the cylindrical case 1 is pressed against the protruding portion 13 of the split piece 8. You may do it.

  Since the split piece 8 is formed with an inclined joining surface 15 so as to form an inwardly extending gap 14 between the split pieces 8 adjacent to each other in the circumferential direction, the split piece 8 protrudes. In a state before the inner peripheral surface of the cylindrical case 1 is pressed into contact with the portion 13, an inwardly extending gap 14 corresponding to the gap 14 is formed between adjacent block bodies 9. As shown in FIG. 5, when the stator core 4 is held in the cylindrical case 1 in a state where the inner peripheral surface of the cylindrical case 1 is pressed against the protruding portion 13 of the divided piece 8, By applying a tightening force P that contracts the outer diameter, the yoke portion 10 is deformed according to the tightening force P, and the adjacent block bodies 9 are in close contact with each other.

  That is, when the outer peripheral surface of the stator core 4 is held in contact with the inner peripheral surface of the cylindrical case 1, the dimension between the outer diameter of the stator core 4 composed of a predetermined number of block bodies 9 and the inner diameter of the cylindrical case 1. A tightening force P corresponding to the difference (tightening allowance) is applied to the stator core 4. A stress generated by pressing the mating surface 15 against the adjacent block body 9 according to the tightening force P is concentrated on the outer peripheral end portion of each mating surface 15, thereby causing the yoke portion 10. Is applied to the outer peripheral end of the block body 9. Thus, when the compressive force Q acts on the portion located on the outer peripheral side of the neutral axis N of the yoke portion 10, a bending moment M acts in a direction corresponding to the increase in the radius of curvature of the yoke portion 10. At the same time, the tensile stress R acts on a portion located on the inner peripheral side of the neutral axis N of the yoke portion 10.

  As described above, the outer peripheral end portion of the block body 9 receives the compressive force Q and contracts and deforms, and the inner peripheral end portion of the block body 9 receives the tensile stress R and expands and deforms. Adjacent block bodies 9 are in close contact with each other. In addition, a region where the tensile stress R is applied to the inner peripheral portion of the yoke portion 10 is formed in accordance with the fastening force P of the stator core 4 applied when the stator core 4 is held by the cylindrical case 1. Even when the stator core 4 is configured using a non-oriented electrical steel sheet, the magnetic flux density can be effectively increased. Therefore, there is a problem that the flow of magnetic flux is greatly hindered as in the case where the inner peripheral side portion of the divided yoke portion is separated from the adjacent divided yoke portion as shown in Patent Document 1 described above. Absent.

  As shown in FIG. 6, the outer diameter D1 of the yoke portion 10 of the block body 9 divided into four in the circumferential direction is set to 198 mm and the inner diameter D2 of the yoke portion 10 so that the data can be easily analyzed. Is set to 170 mm, the protruding amount S of the protruding portion 13 formed on the outer periphery of the yoke portion 10 is set to 1 mm, the width dimension W of the teeth 11 is set to 10 mm, and the inclination angle θ of the mating surface 15 is set. Has a thickness t of 10 mm, and the inner diameter is set to be smaller than the outer diameter of the protruding portion 13 so that the tightening margin applied to the stator core 4 is 150 μm. When the stator core 4 is held in the cylindrical case 1 by the test body constituted by the cylindrical case 1 (see FIG. 5), the cylindrical case 1 is changed to the stator core 4. Depending on the clamping force to be given, it was subjected to a first simulation analysis to verify the change in the stator core 4, to be a state in which the block body 9 adjacent phases are in close contact with each other was confirmed.

  Further, as shown in FIG. 7, the compressive stress from 0 to the tensile stress is applied to the inner peripheral side portion of the yoke portion 10 according to the tightening force of the stator core 4 applied when the stator core 4 is held in the cylindrical case 1. A tensile stress region A in which 20 MPa is applied is formed. On the other hand, a high compressive stress region B1 and a medium compressive stress region B2 in which compressive stress from the cylindrical case 1 acts in a concentrated manner are formed in the vicinity of the base end portion of the protruding portion 13, and the inner peripheral side thereof. A low compressive stress region B3 is formed on the outer peripheral side portion of the yoke portion 10 located in a portion separated from the base end portion of the portion and the protruding portion 13, and a stress region C in which the stress is substantially zero is formed in the other portions. It was confirmed that it was formed. From this data, a region A in which a tensile stress R acts on the inner peripheral side portion of the yoke portion 10 is formed in accordance with the fastening force P of the stator core 4 applied when the stator core 4 is held by the cylindrical case 1. Thus, it was confirmed that excellent magnetic properties can be obtained by effectively reducing the iron loss of the stator core 4.

  Further, the width dimension W of the tooth 11 is set to 30 mm, the inclination angle θ of the mating surface 15 is set to 0.1 °, and the tightening margin applied to the stator core 4 is set to 320 μm. When the stator core 4 is held in the cylindrical case 1 by a test body configured in the same manner as in the first simulation analysis except for the above points, the cylindrical case 1 is applied to the stator core 4. According to the second simulation analysis for verifying the change of the stator core 4 according to the tightening force to be tightened, it was confirmed that the adjacent block bodies 9 were in close contact with each other.

  In the second simulation analysis, according to the tightening force of the stator core 4 applied when the stator core 4 is held in the cylindrical case 1, as shown in FIG. A tensile stress region A in which a compressive stress of 0 to 20 MPa is applied is formed, and an intermediate compressive stress region B2 is formed in the outer peripheral portion of the yoke portion 10 located in the vicinity of the base end portion of the protruding portion 13. At the same time, a low compressive stress region B3 is formed in the outer peripheral side portion of the yoke portion 10 located in a portion separated from the inner peripheral side portion and the base end portion of the protruding portion 13, and the stress is substantially zero in the other portions. It was confirmed that the stress region C was formed. Also from this data, the tensile stress region A in which the tensile stress R acts on the inner peripheral side portion of the yoke portion 10 according to the tightening force P of the stator core 4 applied when the stator core 4 is held by the cylindrical case 1. It was confirmed that by forming the magnetic core, the iron loss of the stator core 4 is effectively reduced and excellent magnetic properties can be obtained.

  On the other hand, as shown in FIG. 9, the protrusions 13 are omitted, and the adjacent block bodies 9 are in close contact with each other before the inclination angle θ of the mating surface 15 is set to 0 and the tightening force is applied. According to the comparative example, which is configured in the same manner as in the second simulation analysis, except that the tightening allowance applied to the stator core 4 is set to 20 μm. When the stator core 4 is held in the cylindrical case 1 in the test body, the change of the stator core 4 according to the tightening force applied from the cylindrical case 1 to the stator core 4 is analyzed. Data as shown was obtained. From this data, it can be seen that in the specimen according to the comparative example in which the inclination angle θ of the mating surface 15 is set to 0 as described above, almost the entire yoke portion 10 becomes the low compressive stress region B3 and the tensile stress region cannot be formed. confirmed.

  An annular stator core 4 is formed by arranging a predetermined number of block bodies 9 formed by laminating a plurality of divided pieces 8 in the rotor rotation axis direction as described above, and an outer peripheral surface of the stator core 4 is formed. In the stator core structure of a rotating electrical machine configured to be held in contact with the inner peripheral surface of the cylindrical case 1, the split piece 8 is provided with the yoke portion 10 and the inner peripheral surface thereof toward the rotor axial direction. And a teeth portion 11 that protrudes in the circumferential direction, and an inclined mating surface 15 is provided so as to form an inwardly extending gap 14 between the circumferentially adjacent divided pieces 8, and the stator core 4 is cylindrical When the case 1 is held, the adjacent block bodies 9 are in close contact with each other according to the tightening force applied from the cylindrical case 1 to the stator core 4. Since setting the inclination angle θ of the interference and the mating surface 15 of the stator core 4, there is an advantage that the effect of increasing the reduction effect and the magnetic flux density superior iron loss of the stator core as an appropriate stress state with a simple configuration is obtained.

  That is, the annular stator core 4 is configured by arranging a predetermined number of block bodies 9 formed by laminating a plurality of divided pieces 8 in the rotor rotation axis direction in the circumferential direction. Compared to the case where the stator core is configured by laminating the electromagnetic steel sheets, there is an advantage that the waste of materials can be suppressed and the manufacturing cost can be reduced. Then, the adjacent block bodies 9 are brought into close contact with each other, for example, by inserting an annular stator core 4 in which a predetermined number of block bodies 9 are provided in the circumferential direction into the cylindrical case 1 and shrink fitting. Therefore, there is an advantage that it is possible to effectively prevent a decrease in magnetic properties due to the formation of a gap between adjacent block bodies 9.

  Further, as shown in the above-described embodiment, the compressive stress is 0 on the inner peripheral side portion of the yoke portion 10 according to the tightening force P of the stator core 4 applied when the stator core 4 is held by one in the cylindrical case. Alternatively, when the tightening margin of the stator core 4 and the inclination angle θ of the mating surface 15 are set so that a region where the tensile stress is applied is formed, the magnetic characteristics of the stator core 4 formed of a non-oriented electrical steel sheet or the like. As a result, it is possible to obtain an excellent magnetic characteristic by effectively preventing a problem that the flow of magnetic flux is greatly obstructed in a portion that is greatly influenced by the magnetic field, that is, the inner peripheral side portion of the yoke portion 10. is there.

  In addition, it replaces with the said embodiment comprised so that the predetermined | prescribed fastening force might be given to the stator core 4 by pressing the protrusion part 13 provided in the outer peripheral surface of the said division | segmentation piece 8 to the inner peripheral surface of the cylindrical case 1. FIG. The entire outer peripheral surface of the annular stator core 4 in which the predetermined number of block bodies 9 are provided in the circumferential direction may be configured to be pressed against the inner peripheral surface of the cylindrical case 1.

  In order to bring the adjacent block bodies 9 into close contact with each other in accordance with the fastening force applied from the cylindrical case 1 to the stator core 4, the fastening margin of the stator core 4 is the outermost diameter portion of the stator core 4. And the inclination angle θ of the mating surface 15 is set within the range of 0.02 ° to 0.2 °, and the cylindrical case 1 is set. It is desirable to set the thickness of the material within the range of 5 mm to 20 mm.

It is a cross-sectional view showing an embodiment of a rotating electrical machine according to the present invention. It is a longitudinal cross-sectional view which shows the specific structure of a rotary electric machine. It is a perspective view which shows the specific structure of a stator core. It is explanatory drawing which shows the state before inserting a stator core in a cylindrical case. It is explanatory drawing which shows the effect | action of this invention. It is explanatory drawing which shows the structure of the division piece for data analysis. It is explanatory drawing which shows the 1st simulation data for confirming the effect of the rotary electric machine which concerns on this invention. It is explanatory drawing which shows the 2nd simulation data for confirming the effect of the rotary electric machine which concerns on this invention. It is explanatory drawing which shows the simulation data in the comparative example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical case 4 Stator core 5 Rotor 6 Rotating shaft 8 Divided piece 13 Protrusion part 14 Clearance 15 Matching surface (theta) Inclination angle

Claims (3)

  An annular stator core is configured by a predetermined number of block bodies formed by laminating a plurality of divided pieces in the rotor rotation axis direction, and an outer circumferential surface of the stator core is an inner circumferential surface of the cylindrical case. A stator core structure of a rotating electrical machine configured to be held in contact with the rotor, wherein the divided piece includes a yoke portion and a tooth portion that protrudes from an inner peripheral surface thereof toward a rotor axial direction. When the stator core is held by the cylindrical case and has a mating surface inclined so as to form an inwardly extending gap between the circumferentially adjacent divided pieces, the stator core In accordance with the tightening force applied to the stator core, the tightening margin of the stator core and the inclination angle of the mating surface are set so that the adjacent block bodies are in close contact with each other. A stator core structure of the rotary electric machine, characterized in that it is a constant.   According to the fastening force of the stator core applied when holding the stator core in the cylindrical case, an area where compressive stress is 0 or tensile stress is formed on the inner peripheral side portion of the yoke part. The stator core structure for a rotating electrical machine according to claim 1, wherein a tightening margin of the stator core and an inclination angle of the mating surface are set.   A projecting portion is formed on the outer peripheral surface of the divided piece so as to project from the yoke portion in the direction opposite to the tooth portion. When the stator core is held by the cylindrical case, the projecting portion is the inner peripheral surface of the cylindrical case. The stator core structure for a rotating electrical machine according to claim 1, wherein a clamping force is applied to the stator core by being pressed against the stator core.

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