Rotating Electric Machine

Abstract

To provide a rotary electric machine which can suppress iron loss without increase of dimensions of a stator core 12 in an axial CL direction.SOLUTION: An annular, namely loop-shaped conductive path is not formed since one convex fitting part 24 is constituted in one area sandwiching one local shear line 28 and has only one convex shear end surface 28a. Consequently, occurrence of iron loss due to eddy current is suppressed in comparison with a conventional convex fitting part constituted by plastically deforming between a pair of local shear lines in a stator core 12. In addition, electromagnetic steel plates 22 are adhered to each other and inconvenience that dimensions of the stator core 12 in an axial CL direction become large is dissolved since an insulation coating film such as adhesives for covering the convex shear end surface 28a is not applied to avoid formation of the annular conductive path.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine having a stator core in which multiple annular electromagnetic steel plates are stacked in the axial direction around an axis, and relates to a technology for suppressing iron loss due to eddy currents generated between the electromagnetic steel plates while maintaining the bonding force required to bond the multiple electromagnetic steel plates to each other. [Background technology]

[0002] A rotating electric machine is well known which includes (a) a stator core having an annular yoke portion centered on the axis and a comb-tooth portion consisting of a plurality of teeth protruding inward at a predetermined interval from the inside of the yoke portion, and (b) the stator core is formed by stacking a plurality of electromagnetic steel sheets having insulating coatings formed on the surfaces in the axial direction. For example, the rotating electric machines described in Patent Document 1 and Patent Document 2 are such machines. In Patent Document 1, a convex fitting portion formed integrally with each of the stacked electromagnetic steel sheets in the form of a flat rivet is formed on each electromagnetic steel sheet, and the convex fitting portion is fitted into a concave fitting portion formed on the back surface of the convex fitting portion of an adjacent electromagnetic steel sheet, thereby fixing the plurality of electromagnetic steel sheets in a stacked state in the axial direction.

[0003] However, the above-mentioned convex fitting portion is formed by plastically deforming a pair of local shear lines of a predetermined length arranged at a predetermined distance from each other into a flat crimp-like shape in one direction in the thickness direction, and when both radial end faces of the flat crimp-like convex fitting portion come into contact with a pair of shear surfaces facing both end faces of the flat crimp-like convex fitting portion formed on an adjacent steel plate, respectively, and become electrically conductive to form an annular conductive path, eddy currents are generated between the adjacent electromagnetic steel plates, resulting in large iron loss.

[0004] In response to this, Patent Document 2 proposes covering both end faces of a flat crimp-shaped convex fitting portion, or a pair of sheared surfaces facing both end faces, with an insulating coating such as a resin adhesive, and then laminating electromagnetic steel sheets. According to this, an insulating coating is interposed between both radial end faces of the flat crimp-shaped convex fitting portion and a pair of sheared surfaces facing both end faces of the flat crimp-shaped convex fitting portion formed on an adjacent steel sheet, so that both end faces and the pair of sheared surfaces are electrically connected, suppressing the generation of iron loss due to the generation of eddy currents. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-002617 A [Patent Document 2] JP 2005-323456 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a rotating electric machine as disclosed in Patent Document 2, an insulating coating applied with a film thickness required to ensure voltage resistance performance is interposed between both radial end faces of the flat crimp-shaped convex fitting portion and a pair of sheared surfaces facing both end faces of the flat crimp-shaped convex fitting portion formed on the adjacent steel plate. Therefore, compared to a stator core of a conventional rotating electric machine in which the electromagnetic steel plates are closely attached to each other, when a stator core is constructed from a laminate of electromagnetic steel plates with an insulating coating interposed therebetween, there is an inconvenience that the axial dimension of the stator core becomes large.

[0007] The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a rotating electric machine in which a plurality of stacked electromagnetic steel sheets are fixed to one another by forming a convex fitting portion on each electromagnetic steel sheet and fitting each convex fitting portion into a concave fitting portion formed on the back surface of the convex fitting portion of an adjacent electromagnetic steel sheet, and which can suppress iron loss without increasing the axial dimension of a stator core in which a plurality of electromagnetic steel sheets are stacked. [Means for solving the problem]

[0008] The inventors of the present invention have conducted various studies to solve the above problems, and have found that a stator core using a convex fitting portion obtained by plastically deforming one of a pair of local regions sandwiching a single local shear line in one direction in the thickness direction of the electromagnetic steel sheet in a flat crimped shape as a fixing means, as compared to a conventional flat crimped convex fitting portion obtained by plastically deforming one of a pair of local regions sandwiching a single local shear line in one direction in the thickness direction of the electromagnetic steel sheet, shows a small temperature rise and generates less heat due to eddy currents when observed using a temperature image of a thermo viewer. It is estimated that by reducing the number of local shear lines used in the plastic processing of one convex fitting portion from two to one, the number of loop-shaped conductive paths formed between the electromagnetic steel sheets is reduced. The present invention has been made based on such findings.

[0009] That is, the gist of the first invention is a rotating electric machine comprising: (a) a stator core having an annular yoke portion centered on an axis, and a comb tooth portion consisting of a plurality of comb teeth protruding inward at a predetermined interval from the inside of the yoke portion, the stator core being formed by stacking a plurality of electromagnetic steel sheets having insulating coatings formed on their surfaces in the axial direction, and a convex fitting portion formed by locally plastically working one electromagnetic steel sheet of a pair of adjacent electromagnetic steel sheets among the plurality of electromagnetic steel sheets being fitted into a concave fitting portion formed on a back side of the convex fitting portion formed by locally plastically working the other electromagnetic steel sheet into a shape similar to the convex fitting portion, thereby fixing the plurality of electromagnetic steel sheets to each other, and (b) the convex fitting portion is formed by plastically deforming one of a pair of local regions sandwiching a single local shear line in a predetermined electromagnetic steel sheet. (c) the convex fitting portion and another convex fitting portion adjacent to the convex fitting portion in the circumferential direction protrude to different sides in the thickness direction of the electromagnetic steel sheet. The point is... The gist of the second invention is a stator core including: (a) an annular yoke portion centered on an axis; and a comb tooth portion consisting of a plurality of comb teeth protruding inward at a predetermined interval from the inside of the yoke portion, the stator core being formed by stacking a plurality of electromagnetic steel sheets having insulating coatings formed on their surfaces in the axial direction, a convex fitting portion formed by locally plastically processing one electromagnetic steel sheet of a pair of adjacent electromagnetic steel sheets among the plurality of electromagnetic steel sheets, the convex fitting portion being locally plastically processed into a shape similar to that of the convex fitting portion on the other electromagnetic steel sheet. a rotating electric machine in which the plurality of electromagnetic steel sheets are fixed to each other by being fitted into a concave fitting portion formed on the back side of the plastically processed convex fitting portion, wherein (b) the convex fitting portion is formed by plastically deforming one of a pair of local regions that sandwich a single local shear line in a specified electromagnetic steel sheet, and (c) the convex fitting portion and another convex fitting portion circumferentially adjacent to the convex fitting portion are formed on mutually different radial sides from the local shear line.

[0010] No. 3 The gist of the invention is that, in the first invention, the convex fitting portion is formed between the local shear line and the outer peripheral edge of the stator core, and the outer peripheral end portion of the convex fitting portion is in contact with the outer peripheral edge of the stator core.

[0011] No. 4 Summary of the invention teeth In the first invention, the convex fitting portion is formed in an area of ​​the stator core that is inner than the center of the radial width of the yoke portion and outer than the radial center of the comb teeth.

[0014] No. 5 The gist of the invention is the first invention to the second invention. 4 In any one of the inventions, the convex fitting portion has a convex shear end surface cut by the local shear line, and is formed so as to become continuously lower than the height of the convex shear end surface as it moves away from the local shear line.

[0015] No. 6 The gist of the invention is the first invention to the second invention. 5In any one of the inventions, the local shear line is arranged in the tangential direction of an arc centered on the axis, and the convex fitting portion has a circumferential width dimension that decreases with increasing distance from the local shear line. Effect of the Invention

[0016] According to the rotating electric machine of the first invention, the convex fitting portion is formed by plastically deforming one of a pair of local regions that sandwich a single local shear line in a specific electromagnetic steel sheet, so that one convex fitting portion has a single convex shear end face. Therefore, the multiple electromagnetic steel sheets are fixed to each other by fitting the convex fitting portion formed on the specific electromagnetic steel sheet into a concave fitting portion formed on the back surface of the convex fitting portion formed on an electromagnetic steel sheet adjacent to the specific electromagnetic steel sheet. In this case, since each convex fitting portion has a single convex shear end surface, even if the convex shear end surface of the convex fitting portion of a certain electromagnetic steel sheet contacts the local shear surface exposed in the concave fitting portion of the adjacent electromagnetic steel sheet and electrically conducts with the convex fitting portion in a state where the convex fitting portion is fitted into the concave fitting portion, each convex fitting portion only has a single convex shear end surface, no annular conductive path is formed, and eddy currents are generated between the adjacent electromagnetic steel sheets, which suppresses the increase in iron loss. In addition, since no insulating coating is applied to avoid the formation of annular conductive paths, the inconvenience of the stator core being larger in the axial direction than the stator core of a conventional rotating electric machine in which the electromagnetic steel sheets are closely attached to each other is eliminated. Moreover, the convex fitting portion and another convex fitting portion adjacent to the convex fitting portion in the circumferential direction protrude to different sides in the thickness direction of the electromagnetic steel sheet. A convex fitting portion having a single convex shear end face is located on either the inner diameter side or the outer diameter side of the local shear line by itself, and can only be fixed in one direction, so there is a possibility that the fixing force is insufficient. In contrast, according to the first invention, the adjacent convex fitting portions are plastically deformed in different directions from each other in the thickness direction of the electromagnetic steel sheet, so that the adjacent electromagnetic steel sheets on both sides are prevented from shifting, and a fixing force between the electromagnetic steel sheets similar to that of a convex fitting portion formed in a flat crimp shape between a conventional pair of local shear lines is obtained. According to the rotating electric machine of the second invention, as in the first invention, one convex fitting portion has a single convex shear end surface. Therefore, even if the convex shear end surface of the convex fitting portion of a certain electromagnetic steel sheet contacts the local shear surface exposed in the concave fitting portion of the adjacent electromagnetic steel sheet and is electrically conductive when the convex fitting portion is fitted into the concave fitting portion, one convex fitting portion only has a single convex shear end surface, so that an annular conductive path is not formed, and eddy currents are generated between the adjacent electromagnetic steel sheets, which suppresses the increase in iron loss. In addition, since an insulating coating is not applied to avoid the formation of an annular conductive path, the inconvenience that the axial dimension of the stator core is larger than that of a conventional rotating electric machine in which the electromagnetic steel sheets are closely attached to each other is eliminated. In addition, the convex fitting portion and another convex fitting portion circumferentially adjacent to the convex fitting portion are formed on different radial sides from the local shear line. A convex fitting portion having a single convex shear end surface is located on either the inner diameter side or the outer diameter side of the local shear line by itself, and can only be fixed in one direction, which may result in insufficient fixing force. In contrast, according to the fifth invention, adjacent convex fitting portions are fixed in different directions from each other, so that if the local shear line is in the circumferential direction, the magnetic steel sheets are prevented from shifting inward or outward, and a fixing force between the magnetic steel sheets similar to that of a convex fitting portion formed in a flat crimp shape between a conventional pair of local shear lines is obtained.

[0017] No. 3According to the rotating electric machine of the invention, the convex fitting portion is formed between the local shear line and the outer peripheral edge of the stator core, and the outer peripheral end of the convex fitting portion is in contact with the outer peripheral edge of the stator core. In the case where the convex fitting portion is formed in one of a pair of local regions sandwiching a single local shear line, the pressing pressure increases, which is an inconvenience. However, according to the second invention, the convex fitting portion can be provided on the outer peripheral edge of the stator core, so that the convex fitting portion to be plastically deformed can be reduced, and the pressing pressure can be made equivalent to that in the conventional case where the convex fitting portion is formed between a pair of local shear lines.

[0018] No. 4 According to the rotating electric machine of the invention, the convex fitting portion is formed in a region of the stator core that is on the inner side of the center of the radial width of the yoke portion and on the outer side of the center of the radial direction of the comb teeth. If slits are formed in the electromagnetic steel plate to suppress the effect of the rotating magnetic field, iron loss can be suppressed, but the current required to obtain the same torque increases, resulting in disadvantages such as a decrease in output density and an increase in copper loss. In contrast, according to the third invention, the convex fitting portion having a single convex shear end face is disposed at the root of the comb teeth of the stator core, so that not only eddy current loss but also loss increased by the rotating magnetic field can be reduced.

[0021] No. 5 According to the rotating electric machine of the invention, the convex fitting portion has a convex shear end surface cut by the local shear line, and is formed so that the height of the convex fitting surface becomes continuously lower as it moves away from the local shear line, thereby making the convex fitting portion having a single convex shear end surface small and locally formed.

[0022] No. 6 According to the rotating electric machine of the present invention, the local shear line is disposed in a tangential direction of a circular arc centered on the axis line, and the convex fitting portion has a circumferential width dimension that is smaller the further away from the local shear line the convex fitting portion is, so that the convex fitting portion having a single convex shear end surface is small and locally formed. [Brief description of the drawings]

[0023] [Figure 1] 1 is a cross-sectional view showing a main part of a rotating electric machine to which the present invention is applied; [Diagram 2] 2 is an enlarged view of a main portion of a stator core provided in the rotating electric machine of FIG. 1; FIG. [Diagram 3] 3 is a cross-sectional view of the stator core taken along line III-III of FIG. 2, showing a transverse section of a protruding fitting portion. [Figure 4] 4 is a cross-sectional view of the stator core taken along line IV-IV of FIG. 2, showing a vertical cross section of a protruding fitting portion. FIG. [Diagram 5] 1 is an enlarged view of a main part of a stator core provided in a rotary electric machine according to another embodiment (embodiment 2) of the present invention, the view corresponding to FIG. 2. FIG. [Figure 6] 6 is a cross-sectional view of the stator core taken along line VI-VI of FIG. 5, showing a transverse section of a convex fitting portion. [Figure 7] 7 is a cross-sectional view of the stator core taken along line VII-VII of FIG. 5, showing a vertical cross section of a protruding fitting portion. [Figure 8] 2. FIG. 4 is an enlarged view of a main part of a stator core provided in a rotary electric machine according to another embodiment (third embodiment) of the present invention, the view corresponding to FIG. [Figure 9] 2. FIG. 4 is an enlarged view of a main part of a stator core provided in a rotary electric machine according to another embodiment (Example 4) of the present invention, the view corresponding to FIG. [Figure 10] 1 is a graph showing the effect of reducing crimping loss in the stator cores of Examples 1, 2, 3, and 4 in comparison with a conventional stator core. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, each drawing is an appropriately simplified schematic diagram, and the dimensional ratios and shapes of each part are not necessarily drawn accurately. EXAMPLES

[0025] Fig. 1 is a cross-sectional view for explaining a schematic configuration of a rotating electric machine MG for a vehicle to which the present invention is suitably applied. The rotating electric machine MG is, for example, a driving source for running a hybrid vehicle or an electric vehicle, and is an AC synchronous motor that functions as an electric motor (motor) or a generator (generator). As shown in Fig. 1, the rotating electric machine MG includes a rotor 10 that is rotatably provided around an axis line CL, and an annular stator core 12 that is disposed on the outer periphery of the rotor 10 and is centered on the axis line CL. The rotor 10 incorporates a plurality of permanent magnets 14 and is rotated by a rotating magnetic field generated by the stator core 12.

[0026] 1 and 2, the stator core 12 includes, for example, a cylindrical yoke portion 16, a comb tooth portion 20 consisting of a plurality of comb teeth 18 protruding from the yoke portion 16 toward the axis line CL at regular intervals in the circumferential direction, and a stator coil (not shown) wound around each of the comb teeth 18. The stator core 12 is formed by stacking magnetic steel sheets 22, each having an insulating coating of about 1 to several μm, such as an organic / inorganic mixed film, fixed to each other and stacked in the direction of the axis line CL.

[0027] 2, 3, and 4 are figures that locally explain the mutual fixing structure of the electromagnetic steel sheets 22 in the rectangular area A1 indicated by the dashed line in FIG. 1, with FIG. 2 being a plan view of the electromagnetic steel sheet 22, FIG. 3 being a cross-sectional view taken along III-III in FIG. 2 showing the horizontal cross-sectional shape of the convex fitting portion 24 formed locally on the electromagnetic steel sheet 22, and FIG. 4 being a cross-sectional view taken along IV-IV in FIG. 2 showing the vertical cross-sectional shape of the convex fitting portion 24 formed on the electromagnetic steel sheet 22.

[0028] One of the plurality of electromagnetic steel sheets 22 that are adjacent to each other is provided with one convex fitting portion 24 that has been locally plastically worked, and the other electromagnetic steel sheet 22 is provided with the other convex fitting portion 24 that has been plastically worked into a shape similar to that of the one convex fitting portion 24, and the other convex fitting portion 24 is fitted by press fitting into a concave fitting portion 26 formed on the back side, i.e., the inside, of the one convex fitting portion 24. By this fitting, the one electromagnetic steel sheet 22 and the other electromagnetic steel sheet 22 that are adjacent to each other are fixed to each other by a pressure force generated by the fitting. Such a fixing structure is applied to each of the adjacent electromagnetic steel sheets among the plurality of electromagnetic steel sheets 22, so that the entire plurality of electromagnetic steel sheets 22 are fixed together.

[0029] The convex fitting portion 24 is formed by plastically deforming only one of a pair of local regions Ri and Ro sandwiching one local shear line 28 in the electromagnetic steel sheet 22. In the embodiment of Fig. 2, a pair of local shear lines 28 corresponding to one comb tooth 18 is formed in two locations along an arc centered on the axis line CL in the tangential direction of the arc, and the convex fitting portion 24 is formed by applying plastic deformation to the outer peripheral local region Ro of the pair of local regions Ri and Ro sandwiching the local shear line 28.

[0030] As shown in FIG. 4, the convex fitting portion 24 is formed in a local region Ro on the outer periphery side of the local shear line 28, and includes a convex shear end surface 28a curved by plastic processing to have a convex stripe shape and a maximum height lower than the thickness of the electromagnetic steel sheet 22, and an inclined convex portion 30 that is continuous with the convex shear end surface 28a and has a lower height and a smaller circumferential width dimension w in a plan view, and forms the concave fitting portion 26 on the back side, i.e., the inside. In the concave fitting portion 26, a linear shear surface 28b formed by the local shear line 28 is exposed, and the concave fitting portion 26 is formed so as to become shallower as it moves away from the linear shear surface 28b. The convex fitting portion 24 and the local shear line 28 are formed in one go, for example, by press processing.

[0031] When the other convex fitting portion 24 is press-fitted into the concave fitting portion 26 formed on the back side, i.e., the inside, of one of the convex fitting portions 24, if the convex shear end surface 28a and the linear shear surface 28b come into contact with each other, it is inevitable that the magnetic steel sheets exposed under the insulating coating will be electrically connected to each other. The dashed line B1 in FIG. 4 indicates the current conduction path between the magnetic steel sheets 22. However, since one convex fitting portion 24 is formed in one region sandwiching one local shear line 28 and has only one convex shear end surface 28a, no annular or loop-shaped conductive path is formed. As a result, the generation of iron loss due to eddy current is suppressed in the stator core 12 compared to a conventional convex fitting portion formed by plastically deforming the area between a pair of local shear lines. In addition, in order to avoid the formation of a ring-shaped conductive path, an insulating coating such as an adhesive is not applied to cover the convex sheared end face 28a, so that the electromagnetic steel sheets 22 are closely attached to each other, eliminating the inconvenience of the dimension of the stator core 12 increasing in the direction of the axis CL.

[0032] In this embodiment, a pair of convex fitting portions 24 are provided parallel to and adjacent to each other in the circumferential direction at portions of the yoke portion 16 corresponding to the bases of the comb teeth 18, and one and the other of the pair of convex fitting portions 24 protrude alternately, i.e., in opposite directions, in the thickness direction of the electromagnetic steel sheets 22. This prevents the electromagnetic steel sheets 22 from shifting either inward or outward, ensuring a fixing force.

[0033] An embodiment of the present invention will be described in detail below with reference to the drawings. Note that in the following embodiment, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0034] 5, 6, and 7 are views for locally explaining the mutual fixing structure of electromagnetic steel sheets 22 according to another embodiment of the present invention in the rectangular region indicated by the dashed line in Fig. 1, and Fig. 5 is a plan view of the electromagnetic steel sheet 22. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5, showing the horizontal cross-sectional shape of a convex fitting portion 124 locally formed on the electromagnetic steel sheet 22. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 2, showing the vertical cross-sectional shape of the convex fitting portion 124 formed on the electromagnetic steel sheet 22.

[0035] The convex fitting portion 124 of the present embodiment is formed between the local shear line 28 and the outer peripheral edge of the electromagnetic steel sheet 22 as compared with the convex fitting portion 24 of the first embodiment, and differs in that the convex fitting portion 124 has a convex portion 130 of approximately constant height instead of the inclined convex portion 30 which decreases in height and width in plan view the further away from the convex shear end face 28a it is, and in that it forms a concave insertion portion 126 of approximately constant depth, but otherwise is the same as the convex fitting portion 24 of the first embodiment.

[0036] According to this embodiment, the convex fitting portion 124 is formed between the local shear line 28 and the outer peripheral edge 12a of the stator core 12, and the outer peripheral end 124a of the convex fitting portion 124 is in contact with the outer peripheral edge 12a of the stator core 12. When the convex fitting portion 24 is formed in one of a pair of local regions Ri, Ro that sandwich a single local shear line 28, the pressing pressure increases, which is an inconvenience. However, according to this embodiment, the convex fitting portion 124 can be provided on the outer peripheral edge of the stator core 12, so that the convex fitting portion 124 to be plastically deformed can be reduced, and the pressing pressure can be made equivalent to that in the conventional case in which the convex fitting portion is formed between a pair of local shear lines. EXAMPLES

[0037] FIG. 8 is a plan view showing a root region RR of a comb tooth 18 of the electromagnetic steel sheet 22, which is a view for locally explaining a mutual fixing structure of an electromagnetic steel sheet 22 according to another embodiment of the present invention. The root region RR of the comb tooth 18 is a region on the inner periphery side of the center of the radial width of the yoke portion 16 and on the outer periphery side of the center of the radial direction of the comb tooth 18, and is a region surrounded by a dashed line in FIG. 8. The convex fitting portion 224 of this embodiment is formed in each of the root regions RR provided corresponding to each comb tooth 18. In FIG. 8, one convex fitting portion 224 formed in the root region RR corresponding to a specific comb tooth 18 and one convex fitting portion 224 formed in the root region RR corresponding to the comb tooth 18 adjacent to the specific comb tooth 18 and forming a concave fitting portion 226 on the back surface are provided in opposite directions in the thickness direction of the electromagnetic steel sheet 22.

[0038] Generally, when slits are formed in an electromagnetic steel sheet to suppress the effect of a rotating magnetic field, iron loss can be suppressed, but the current required to obtain the same torque increases, resulting in disadvantages such as a decrease in power density and an increase in copper loss. In contrast, according to this embodiment, the convex fitting portion 224 having a single convex sheared end surface 28a is disposed within the root region RR of the comb teeth of the stator core 12, so that not only eddy current loss but also loss increased by a rotating magnetic field can be reduced.

[0039] 8, the dashed arrows representatively indicate the magnetic flux in the yoke portion 16 of the stator core 12 and in the comb teeth 18 of the comb tooth portion 20. In a conventional flat rivet-shaped convex fitting portion plastically processed between a pair of local shear lines of electromagnetic steel sheets, electrical current flows between adjacent electromagnetic steel sheets at two locations, and eddy currents are generated in the current loops passing through each of the two locations, causing increased heat generation and iron loss. EXAMPLES

[0040] Fig. 9 is a diagram for locally explaining the mutual fixing structure of the electromagnetic steel sheet 22 according to another embodiment of the present invention, and is a plan view showing a portion of the electromagnetic steel sheet 22 where the convex fitting portion 24 is provided. In the embodiment of Fig. 9, a pair of local shear lines 28 corresponding to one comb tooth 18 are formed in the tangential direction of the arc at two points along the arc centered on the axis line CL, and a pair of convex fitting portions 324 are formed by applying plastic deformation to the outer circumferential local region Ro and the inner circumferential local region Ri of a pair of local regions Ri and Ro sandwiching the local shear line 28. In Fig. 9, a concave fitting portion 326 is formed on the back surface of the pair of convex fitting portions 324.

[0041] 10 is a graph showing the iron loss of the stator core 12 to which the electromagnetic steel sheet 22 is joined using the convex fitting portion 24 of Example 1, the stator core 12 to which the electromagnetic steel sheet 22 is joined using the convex fitting portion 124 of Example 2, the convex fitting portion 224 of Example 3, and the stator core 12 to which the electromagnetic steel sheet 22 is joined using the convex fitting portion 324 of Example 4, measured at a frequency of 400 Hz and an amplitude value of 1.25 T of the magnetic flux density of the yoke portion 16, and showing the relative value of the crimping loss reduction effect of each of Examples 1, 2, and 3 compared with the relative value of the conventional stator core joined using the conventional flat crimp-shaped convex fitting portion by plastically deforming the area between a pair of local shear lines into a flat crimp shape. In each of Examples 1, 2, 3, and 4, a loss reduction of 23% or more is obtained compared to the conventional value.

[0042] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0043] For example, in the yoke portion 16 of the electromagnetic steel plate 22 constituting the stator core 12 in the above-described embodiment, one or two convex fitting portions 24, 124, 224, 324 are provided corresponding to one comb tooth 18, but the convex fitting portions 24, 124, 224, 324 do not necessarily have to be provided for each comb tooth 18, and may be provided corresponding to two or more comb teeth 18.

[0044] In the above-described embodiment, the height of the convex fitting portion 24 , 124 , 224 , 324 is smaller than the thickness of the electromagnetic steel sheet 22 , but it may be larger than the thickness of the electromagnetic steel sheet 22 .

[0045] Furthermore, in the above-described embodiment, the rotating electric machine MG is for use in a vehicle, but it may also be used in mobility other than a vehicle, such as an air vehicle or a ship.

[0046] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0047] 10: Rotor 12: Stator core 14: Permanent magnet 16: York section 18: Comb teeth 20: Comb teeth part 22:Electromagnetic steel plate 24, 124, 224, 324: Convex fitting part 26, 126, 226, 326: Concave inset part 28: Local shear line 28a: Convex shear end face 28b: Straight shear plane 30: Inclined convex part 130: Convex

Claims

1. a rotating electric machine comprising a stator core having an annular yoke portion centered on an axis, and a comb tooth portion consisting of a plurality of comb teeth protruding inward at predetermined intervals from the inside of the yoke portion, wherein the stator core is made of a plurality of electromagnetic steel sheets, each having an insulating coating formed on its surface, stacked in the axial direction, and wherein a convex fitting portion formed by locally plastically working one electromagnetic steel sheet of a pair of adjacent electromagnetic steel sheets among the plurality of electromagnetic steel sheets is fitted into a concave fitting portion formed on a back side of the convex fitting portion formed by locally plastically working the other electromagnetic steel sheet into a shape similar to the convex fitting portion, thereby fixing the plurality of electromagnetic steel sheets to each other, the protruding fitting portion is formed by plastically deforming one of a pair of local regions that sandwich a single local shear line in a predetermined electromagnetic steel sheet, The convex fitting portion and another convex fitting portion adjacent to the convex fitting portion in the circumferential direction protrude to different sides in the thickness direction of the electromagnetic steel sheet. A rotating electric machine characterized by:

2. A rotating electric machine comprising a stator core having an annular yoke portion centered on an axis, and a comb tooth portion consisting of a plurality of comb teeth protruding inward at predetermined intervals from the inside of the yoke portion, wherein the stator core is made of a plurality of electromagnetic steel plates stacked in the axial direction, each having an insulating coating formed on its surface, and wherein a convex fitting portion formed by locally plastically processing one electromagnetic steel plate of a pair of adjacent electromagnetic steel plates among the plurality of electromagnetic steel plates is fitted into a concave fitting portion formed on the back side of the convex fitting portion formed by locally plastically processing the other electromagnetic steel plate into a shape similar to the convex fitting portion, thereby fixing the plurality of electromagnetic steel plates to each other, the protruding fitting portion is formed by plastically deforming one of a pair of local regions that sandwich a single local shear line in a predetermined electromagnetic steel sheet, The convex fitting portion and another convex fitting portion adjacent to the convex fitting portion in the circumferential direction are formed on different sides from each other in the radial direction from the local shear line. A rotating electric machine characterized by:

3. The convex fitting portion is formed between the local shear line and an outer circumferential edge of the stator core, The outer peripheral end of the protruding fitting portion is in contact with the outer peripheral edge of the stator core.

3. The rotating electric machine according to claim 1 or 2.

4. The protruding fitting portion is formed in a region of the stator core that is on the inner circumferential side of the center of the radial width of the yoke portion and on the outer circumferential side of the center of the radial direction of the comb teeth.

3. The rotating electric machine according to claim 1 or 2.

5. The convex fitting portion has a convex shear end surface cut by the local shear line, and is formed so that the height of the convex shear end surface becomes continuously lower as it moves away from the local shear line.

5. The rotating electric machine according to claim 1, wherein the first and second poles are arranged in a first direction.

6. the local shear line is disposed tangentially to an arc about the axis; The convex fitting portion has a circumferential width dimension that decreases as it moves away from the local shear line.

6. The rotating electric machine according to claim 1,

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