Stator core, method for manufacturing a stator, and rotating electric machine

Abstract

A stator core 20 includes a belt-like first core 24 and a plurality of second cores 26. The first core 24 has a plurality of first yoke component parts 24a and a plurality of connection parts 24b for connecting first yoke component parts 24a circumferentially adjacent to each other. The second cores 26 each have a second yoke component part 26a held between an adjacent pair of the first yoke component parts 24a and a teeth component part 26b protruding radially inward as compared to the corresponding first yoke component part 24a. The first yoke component parts 24a and the second yoke component parts 26a are respectively connected to each other at first connection surfaces 40 and second connection surfaces 60.

Description

[Technical Field]

[0001] The present invention relates to a split stator core, a method for manufacturing a stator using the stator core, and a rotary electric machine comprising the stator core. [Background Art]

[0002] As a stator core for rotary electric machines such as electric motors and generators, split stator cores having a configuration in which a yoke and teeth are split are often used.

[0003] For example, the stator for a rotary electric machine disclosed in Patent Document 1 comprises a stator core formed by combining a plurality of yoke core sections positioned on the outer peripheral side of slots and tooth core sections connecting the plurality of yoke core sections to each other. Circumferential contact surfaces facing the tooth core sections are respectively provided on both sides of each yoke core section in the circumferential direction of the stator core. Similarly, circumferential contact surfaces facing the yoke core sections are respectively provided on both sides of each tooth core section in the circumferential direction. Each circumferential contact surface is formed such that the yoke core section can be arranged from the outer peripheral side between a pair of adjacent tooth core sections. Further, each circumferential contact surface is formed such that the tooth core section cannot be pulled out to the inner peripheral side from between a pair of adjacent yoke core sections.

[0004] In the stator for a rotary electric machine disclosed in Patent Document 1, after arranging a plurality of tooth core sections in pre-wound coils, the stator core can be completed by combining the plurality of yoke core sections and the plurality of tooth core sections. This allows the coils to be easily arranged on the stator core. [Prior Art Literature] [Patent Literature]

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2010-233387 [Summary of the Invention] [Problems that the invention aims to solve]

[0006] As described above, in the stator for a rotating electric machine of Patent Document 1, the circumferential contact surfaces of the yoke core and the tee core are formed in such a way that the tee core cannot be pulled out from between the pair of yoke cores toward the inner circumference. This prevents the tee core from moving toward the inner circumference relative to the yoke core when the yoke core is fixed in the appropriate position.

[0007] However, the circumferential contact surface cannot sufficiently prevent the yoke core from moving outward relative to the tee core. For this reason, the stator for a rotating electric machine described in Patent Document 1 requires a means to restrict the movement of the yoke core outward, separate from the circumferential contact surface. However, even with such a means, it is difficult to sufficiently prevent the movement of the yoke core.

[0008] Therefore, the present invention aims to provide a split-type stator core that can properly fix the yoke and teeth, and a rotating electric machine equipped therewith. [Means for solving the problem]

[0009] The present invention relates to the following stator core, a method for manufacturing a stator, and a rotating electric machine.

[0010] (1) A split-type stator core having a cylindrical yoke and a plurality of teeth protruding inward from the yoke in the radial direction, It includes a strip-shaped first core and a plurality of second cores fixed to the first core so as to protrude inward from the first core in the radial direction of the yoke, The first core has a plurality of first yoke components that constitute the yoke and are arranged at intervals in the circumferential direction of the yoke, and a plurality of connecting components that connect the radial outer edges of adjacent first yoke components in the circumferential direction. The second core has a second yoke component that constitutes the yoke and is sandwiched between a pair of circumferentially adjacent first yoke components, and a tooth component that constitutes the teeth and protrudes radially inward from the pair of first yoke components. The first yoke component has first connecting surfaces on both sides in the circumferential direction, which are connected to the second yoke component. The second yoke component has second connecting surfaces on both sides in the circumferential direction, which are connected to the first connecting surface of the first yoke component. When viewed from the axial direction of the yoke, if a hypothetical straight line extending radially through the center of the first yoke component in the circumferential direction is defined as the reference line of the first yoke component, the first connecting surface includes a first inclined surface that is inclined with respect to the reference line such that the outer side in the radial direction approaches the reference line in the circumferential direction, and a second inclined surface that is provided radially inward of the first inclined surface and is inclined with respect to the reference line such that the inner side in the radial direction approaches the reference line in the circumferential direction. A stator core in which, when viewed from the axial direction, the second connecting surface connected to the first connecting surface of the first yoke component has a third inclined surface and a fourth inclined surface that are inclined with respect to the reference line so as to be in line with the first inclined surface and the second inclined surface of the first yoke component.

[0011] (2) The teeth component has a coil support portion that supports the coil, The stator core according to (1) above, wherein the width of the second yoke component is smaller than the width of the coil support component in the circumferential direction.

[0012] (3) The stator core according to (1) or (2) above, wherein, when viewed from the axial direction, a virtual circle is defined as the reference circle, centered on the axis of the yoke and circumscribing the plurality of first yoke components, a recess is formed on the radial outer surface of the connecting portion that is recessed inward in the radial direction compared to the reference circle.

[0013] (4) The stator core according to any one of (1) to (3) above, wherein the connecting portion is integrally molded with the adjacent pair of first yoke components.

[0014] (5) The connecting portion has a first connecting portion and a second connecting portion arranged in the circumferential direction, The first connecting portion has a third connecting surface that faces the second connecting portion side in the circumferential direction, The second connecting portion has a fourth connecting surface that faces the first connecting portion side in the circumferential direction and is connected to the third connecting surface. The stator core according to any one of (1) to (4) above, wherein the first connecting portion and the second connecting portion are integrally continuous with respect to the area outside the third connecting surface and the fourth connecting surface in the radial direction.

[0015] (6) The stator core according to any one of (1) to (5) above, wherein the first core and the plurality of second cores each include a plurality of stacked non-oriented electrical steel sheets.

[0016] (7) A method for manufacturing a stator having a stator core as described in any of (1) to (6) above, The first core, in its unfolded state, is placed outside the coils arranged in a ring shape. A method for manufacturing a stator, comprising inserting the plurality of second cores sequentially into the coil and the first core from the inside of the coil, while curving the first core along the outer circumference of the coil, thereby attaching the coil and the plurality of second cores to the first core.

[0017] (8) A stator core as described in any of (1) to (6) above, a coil supported by the plurality of teeth of the stator core, and a rotor disposed inside the stator core. The rotating electric machine.

Effect of the Invention

[0018] According to the present invention, it is possible to obtain a split-type stator core capable of properly fixing a yoke and teeth, and a rotating electric machine including the same.

Brief Description of Drawings

[0019] [Figure 1] It is a diagram showing the configuration of a rotating electric machine according to an embodiment of the present invention. [Figure 2] It is a diagram showing a first core. [Figure 3] It is an enlarged view showing a connecting portion between the first core and the second core. [Figure 4] It is a diagram for explaining a method of manufacturing a stator. [Figure 5] It is a diagram showing another example of the first core. [Figure 6] It is a diagram showing still another example of the first core. [Figure 7] It is a diagram showing yet another example of the first core. [Figure 8] It is a diagram showing another example of a rotating electric machine. [Figure 9] It is a diagram showing still another example of a rotating electric machine. [Figure 10] It is a diagram showing yet another example of a rotating electric machine. [Figure 11] It is a diagram showing a stator of a reference example.

Mode for Carrying Out the Invention

[0020] Hereinafter, a stator core according to an embodiment of the present invention and a rotating electric machine including the same will be described with reference to the drawings.

[0021] (Configuration of Rotating Electric Machine) Figure 1 is a schematic diagram showing the configuration of a rotating electric machine according to one embodiment of the present invention. In Figure 1, the rotating electric machine 100 is shown as viewed from the axial direction of the yoke 20a, which will be described later. Also, in Figure 1, only one-quarter of the circumferential region of the rotating electric machine 100 is shown.

[0022] As shown in Figure 1, the rotating electric machine 100 comprises a stator 10, a rotor 12, and a case 14. Note that, to avoid complexity in the drawing, the rotor 12 and the coil 22 (described later) are shown in a simplified manner.

[0023] The stator 10 has a stator core 20 and a coil 22. The rotor 12 is positioned inside the stator core 20 such that its axis (center of rotation) coincides with the axis of the stator core 20. The case 14 is attached to the outer surface of the stator core 20, for example, by shrink fitting. Various known configurations can be used for the rotor 12 and case 14, so a detailed description is omitted.

[0024] The stator core 20 has a cylindrical yoke 20a and a plurality of teeth 20b that protrude inward from the yoke 20a in the radial direction. The coil 22 is supported by the plurality of teeth 20b. In this embodiment, the coil 22 may be supported by the plurality of teeth 20b in a distributed winding state, or in a concentrated winding state.

[0025] In this embodiment, the stator core 20 is equipped with 24 teeth 20b, but the number of teeth is not limited to 24. In the following, when simply referred to as "axial direction," it means the axial direction of the yoke 20a; when simply referred to as "circumferential direction," it means the circumferential direction of the yoke 20a; and when simply referred to as "radial direction," it means the radial direction of the yoke 20a.

[0026] In this embodiment, the stator core 20 is a segmented stator core and includes a strip-shaped first core 24 and a plurality of second cores 26 fixed to the first core 24 so as to protrude radially inward from the first core 24. The first core 24 and the second cores 26 can each be formed, for example, by laminating a plurality of plates of a predetermined shape obtained by punching out an electromagnetic steel sheet.

[0027] In this embodiment, known non-oriented electrical steel sheets are used as the electrical steel sheets constituting the first core 24 and the second core 26. Whether the steel sheets constituting the first core 24 and the second core 26 are grain-oriented or non-oriented electrical steel sheets can be determined by measuring the magnetic flux density of the steel sheets. The magnetic flux density can be measured using a well-known Tesla meter.

[0028] Figure 2 shows the first core 24, where (a) shows the first core 24 incorporated into the rotating electric machine 100, and (b) shows the first core 24 in an unfolded state before being incorporated into the rotating electric machine 100.

[0029] As will be described in detail later, the rotating electric machine 100 uses one or more strip-shaped first cores 24 that are curved in an annular or arc shape. In this embodiment, one first core 24 is used curved in an annular shape. As shown in Figures 1 and 2, the first core 24 has a plurality of first yoke components 24a and a plurality of connecting components 24b. The plurality of first yoke components 24a constitute the yoke 20a and are arranged at intervals in the circumferential direction. Each connecting component 24b connects the radial outer edges of adjacent first yoke components 24a in the circumferential direction. In this embodiment, the connecting component 24b is integrally molded with a pair of adjacent first yoke components 24a.

[0030] As shown in Figure 2(a), the reference circle 50 is a virtual circle that, when viewed from the axial direction, is centered on the axis of the yoke 20a and circumscribing the plurality of first yoke components 24a. In this embodiment, when viewed from the axial direction, a recess 28 is formed on the radial outer surface of the connecting portion 24b, which is recessed radially inward from the reference circle 50. In this embodiment, the first core 24 is formed such that the entire outer surface of the connecting portion 24b is recessed.

[0031] Figure 3 is an enlarged view showing the connection between the first core 24 and the second core 26. As shown in Figures 1 and 3, in this embodiment, the second core 26 has a second yoke component 26a and a teeth component 26b.

[0032] The second yoke component 26a constitutes the yoke 20a and is sandwiched between a pair of circumferentially adjacent first yoke components 24a. The teeth component 26b constitutes the teeth 20b and protrudes radially inward from the pair of adjacent first yoke components 24a. In this embodiment, the teeth component 26b has a coil support component 30 that is continuously provided on the second yoke component 26a and supports the coil 22, and a flange component 32 provided at the tip of the coil support component 30 (the radially inward end) so as to protrude on both sides in the circumferential direction from the coil support component 30. In this embodiment, in the circumferential direction, the width of the second yoke component 26a is set to be the same as or smaller than the width of the coil support component 30. In the example shown in Figure 1, in the circumferential direction, the minimum width of the second yoke component 26a is smaller than the minimum width of the coil support component 30.

[0033] As shown in Figure 3, the first yoke component 24a has first connecting surfaces 40 on both sides in the circumferential direction, which are connected to the second yoke component 26a. The second yoke component 26a also has second connecting surfaces 60 on both sides in the circumferential direction, which are connected to the first connecting surfaces 40. The first connecting surfaces 40 are formed to be convex outward in the circumferential direction. The second connecting surfaces 60 are formed to be concave inward in the circumferential direction.

[0034] As shown in Figures 1 and 3, when viewed from the axial direction, a hypothetical straight line extending radially through the center of the first yoke component 24a in the circumferential direction is defined as the reference line L1 of the first yoke component 24a. In addition to the reference line L1, Figure 3 also shows straight lines L2 to L5 that are parallel to the reference line L1 when viewed from the axial direction.

[0035] As shown in Figure 3, the first connecting surface 40 of the first yoke component 24a includes a first inclined surface 40a and a second inclined surface 40b. Viewed from the axial direction, the first inclined surface 40a is inclined with respect to the reference line L1 such that the outer side in the radial direction approaches the reference line L1 in the circumferential direction. The second inclined surface 40b is provided radially inward of the first inclined surface 40a. Furthermore, the second inclined surface 40b is inclined with respect to the reference line L1 such that the inner side in the radial direction approaches the reference line L1 in the circumferential direction.

[0036] Viewed from the axial direction, the second connecting surface 60 of the second yoke component 26a includes a third inclined surface 60a connected to the first inclined surface 40a of the first connecting surface 40, and a fourth inclined surface 60b connected to the second inclined surface 40b of the first connecting surface 40. The third inclined surface 60a is inclined with respect to the reference line L1 so as to be aligned with the first inclined surface 40a to which it is connected, and the fourth inclined surface 60b is inclined with respect to the reference line L1 so as to be aligned with the second inclined surface 40b to which it is connected.

[0037] In this embodiment, the angle α between the reference line L1 (straight lines L2, L3) and the first inclined surface 40a, as viewed from the axial direction, is set to, for example, 5° or more. In this embodiment, compressive stress is generated in the first yoke component 24a due to contact between the first inclined surface 40a and the third inclined surface 60a. This compressive stress is assumed to occur in a direction perpendicular to the first inclined surface 40a. On the other hand, the iron loss of the first yoke component 24a increases when it is excited in a direction parallel to the direction in which the compressive stress is applied. In this embodiment, the first yoke component 24a is mainly excited in the circumferential direction. Therefore, if the generation of circumferential compressive stress in the first yoke component 24a can be suppressed, the increase in iron loss can be suppressed. Thus, in this embodiment, it is preferable to set the angle α to 5° or more so as to sufficiently suppress the application of circumferential compressive stress from the third inclined surface 60a to the first yoke component 24a. Furthermore, when viewed from the axial direction, the angle between the reference line L1 and the third inclined surface 60a is set in the same way as the angle α described above. In this embodiment, by setting the angle α to 5° or more, the movement of the first yoke component 24a radially outward relative to the second yoke component 26a, and the movement of the second yoke component 26a radially inward relative to the first yoke component 24a are sufficiently suppressed. This ensures sufficient fixing strength between the first core 24 and the second core 26.

[0038] Furthermore, in this embodiment, the angle α is set to, for example, 30° or less. In the rotating electric machine 100 according to this embodiment, the direction of the magnetic flux flowing through the second core 26 changes according to the rotation of the rotor 12 (see Figure 1). Specifically, there are cases in which the magnetic flux mainly flows in the circumferential direction, and cases in which the magnetic flux flows radially through the teeth component 26b, then changes direction in the circumferential direction in a smooth curve at the second yoke component 26a and flows into the first yoke component 24a. Here, an air gap usually occurs between the first inclined surface 40a and the third inclined surface 60a due to machining accuracy issues. Viewed from the axial direction, the first inclined surface 40a and the third inclined surface 60a are inclined with respect to the reference line L1, so the air gap is also formed to extend in a direction inclined with respect to the reference line L1. When the inclination angle of the inclined surfaces 40a and 60a with respect to the reference line L1 increases, the direction in which the magnetic flux flows and the length direction of the air gap become nearly parallel when the magnetic flux flows in a curve from the teeth component 26b toward the first yoke component 24a as described above. In this case, the length of the air gap in the direction in which the magnetic flux flows increases, and the excitation of the yoke 20a is hindered. As a result, iron loss increases. Therefore, in this embodiment, it is preferable to set the angle α to 30° or less so that the length of the air gap in the direction in which the magnetic flux flows is reduced. Furthermore, by setting the angle α to 30° or less, interference between the first core 24 and the second core 26 can be sufficiently prevented when inserting the second core 26 into the first core 24. This makes it easy to insert the second core 26 into the first core 24.

[0039] Furthermore, when viewed from the axial direction, the angle β between the reference line L1 (straight lines L4, L5) and the second inclined surface 40b is set to 180° / n+5° to 180° / n+30°, for example, when n is the number of teeth 20b designed as the stator core 20. The angle between the reference line L1 and the fourth inclined surface 60b of the second yoke component 26a is set in the same way as the angle β above. By setting the angle β to 180° / n+5° or more, it is possible to suppress the application of circumferential compressive stress from the fourth inclined surface 60b to the first yoke component 24a. As described above, the first yoke component 24a is mainly excited in the circumferential direction, so by suppressing circumferential compressive stress, it is possible to suppress the increase in iron loss. Furthermore, by setting the angle β to 180° / n+5° or greater, the radial inward movement of the first yoke component 24a relative to the second yoke component 26a, and the radial outward movement of the second yoke component 26a relative to the first yoke component 24a, are sufficiently suppressed. This ensures sufficient fixing strength between the first core 24 and the second core 26.

[0040] In this embodiment, each connecting portion 24b is formed to be easily deformed when the first core 24 is curved in an annular or arc shape. Specifically, the radial thickness of the connecting portion 24b is set to be sufficiently small compared to the radial length of the second yoke component 26a. In this embodiment, the thickness of the portion of the connecting portion 24b with the smallest thickness in the radial direction is set to 1 / 2 or less of the radial length of the second yoke component 26a. Preferably, the thickness of the portion of the connecting portion 24b with the smallest thickness in the radial direction is set to 1 / 5 or less of the radial length of the second yoke component 26a, and more preferably to 1 / 10 or less.

[0041] Furthermore, in this embodiment, the length of the recess 28 in the circumferential direction is set to be greater than the thickness of the portion of the second yoke component 26a in the circumferential direction where the thickness is smallest.

[0042] (Method of manufacturing a stator) Below, we will briefly describe an example of a method for manufacturing the stator 10. Figure 4 is a diagram illustrating the method for manufacturing the stator 10.

[0043] As shown in Figure 4(a), in the manufacturing method according to this embodiment, first, the unfolded first core 24 is placed on the outside of the coil 22, which is arranged in an annular shape when viewed from the axial direction. Next, as shown in Figures 4(b) and (c), the second core 26 is inserted from the inside of the coil 22 into the coil 22 and the first core 24 (more specifically between the pair of first yoke components 24a), while the first core 24 is curved along the outer circumference of the coil 22. In this way, a plurality of second cores 26 are inserted sequentially into the coil 22 and the first core 24. As a result, the coil 22 and the plurality of second cores 26 are attached to the first core 24, and the stator 10 (see Figure 1) is manufactured.

[0044] When winding wires directly onto the stator core, lap winding is typically used, where the windings overlap. However, interference between windings inevitably leads to larger coil ends. Wave winding is a winding method that reduces overlap between windings compared to lap winding. Wave winding allows for efficient placement of the conductors in the available space, resulting in smaller coil ends. However, the workspace between teeth is small, so attempting to process the conductors into a wave wind shape when directly winding them onto the stator core causes interference between the teeth and the conductor processing robot. Therefore, it is practically difficult to use wave winding when directly winding conductors onto the stator core. On the other hand, wave winding is possible when assembling a segment coil, which consists of multiple conductors pre-processed into a wave wind shape, onto the stator core. However, this requires welding multiple conductors together at the coil end. Therefore, even when using segment coils, the enlargement of the coil end due to the weld is unavoidable. In contrast to these, the manufacturing method according to this embodiment allows for the production of the stator 10 without using segmented coils by preparing coils in advance with both coil ends having a wave-wound shape in a work space with fewer constraints. In this case, it becomes easier to miniaturize the coil ends.

[0045] In this embodiment, the width of the second yoke component 26a is smaller than the width of the coil support component 30 in the circumferential direction. By reducing the width of the second yoke component 26a in this way, the second yoke component 26a can be easily inserted between a pair of adjacent first yoke components 24a.

[0046] (Effects and Benefits) In this embodiment, as explained in Figure 3, the first core 24 and the second core 26 are connected by the contact between the first inclined surface 40a and the third inclined surface 60a, and by the contact between the second inclined surface 40b and the fourth inclined surface 60b radially inward from the first inclined surface 40a and the third inclined surface 60a. The first connecting surface 40 is inclined with respect to the reference line L1 such that the outer radial side approaches the reference line L1 in the circumferential direction, and the second inclined surface 40b is inclined with respect to the reference line L1 such that the inner radial side approaches the reference line L1 in the circumferential direction. The third inclined surface 60a is inclined with respect to the reference line L1 along the first inclined surface 40a to which it is connected, and the fourth inclined surface 60b is inclined with respect to the reference line L1 along the second inclined surface 40b to which it is connected.

[0047] With the above configuration, radial outward movement of the first core 24 is prevented by the first inclined surface 40a of the first core 24 contacting the third inclined surface 60a of the second core 26. Radially inward movement of the second core 26 is prevented by the third inclined surface 60a of the second core 26 contacting the first inclined surface 40a of the first core 24. Furthermore, radial outward movement of the second core 26 is prevented by the fourth inclined surface 60b of the second core 26 contacting the second inclined surface 40b of the first core 24. In this way, in this embodiment, the second yoke component 26a of the second core 26 can be securely fixed between a pair of adjacent first yoke components 24a. That is, the yoke 20a and the multiple teeth 20b can be properly fixed. As a result, vibrations in the stator 10 when the rotating electric machine 100 is in use can be sufficiently suppressed.

[0048] Furthermore, in this embodiment, the first connecting surface 40 of the first yoke component 24a is formed to be convex outward in the circumferential direction, and the second connecting surface 60 of the second yoke component 26a is formed to be concave inward in the circumferential direction. In this case, even without requiring very high dimensional accuracy of the first connecting surface 40 and the second connecting surface 60, the second core 26 can be naturally moved to the appropriate position (design position) along the first connecting surface 40. This allows the first connecting surface 40 and the second connecting surface 60 to come into contact with sufficient force. As a result, the rigidity and shape accuracy of the stator core 20 can be sufficiently high.

[0049] In this embodiment, as described above, the first connecting surface 40 and the second connecting surface 60 are in contact with sufficient force, so a compressive stress of a certain magnitude in the circumferential direction is generated at the contact area between the first yoke component 24a and the second yoke component 26a. For this reason, if the first core 24 is constructed of grain-oriented electrical steel sheet such that the first yoke component 24a has high magnetic permeability in the circumferential direction, the flow of magnetic flux may be obstructed at the contact area between the first yoke component 24a and the second yoke component 26a. In this case, even if the first core 24 is constructed of grain-oriented electrical steel sheet, the increase in iron loss may not be sufficiently suppressed. For this reason, when the first core is constructed of grain-oriented electrical steel sheet, a stator may be constructed as shown in Figure 11, for example. In the stator shown in Figure 11, the second yoke component 260a of the second core 260 is simply inserted between the pair of first yoke components 240a of the first core 240 and fixed to the first core 240 by adhesive. In this case, compared to the case in the stator 10 according to this embodiment, where the first yoke component 24a is sandwiched between adjacent second yoke components 26a to fix the first core 24 and the second core 26, it is possible to suppress the generation of compressive stress in the circumferential direction at the first yoke component 240a. This makes it possible to suppress the increase in iron loss. On the other hand, in the stator 10 according to this embodiment, the first core 24 is made of non-oriented electrical steel sheet. Therefore, even if a compressive stress of a certain magnitude is generated in the circumferential direction at the contact portion between the first yoke component 24a and the second yoke component 26a, the flow of magnetic flux is not obstructed. As a result, it is possible to suppress the increase in iron loss.

[0050] Furthermore, in this embodiment, a recess 28 is formed on the outer surface of the connecting portion 24b located radially outside the second core 26. In this case, even if the connecting portion 24b deforms to bulge outward when the second core 26 is attached to the first core 24, it is possible to prevent the connecting portion 24b from protruding radially beyond the first yoke component 24a. This allows the stator 10 to be smoothly inserted into the case 14. The recess 28 can also be used as a fixing location when fixing the stator 10 to the case 14. If the case 14 is fixed to the stator 10 without shrink fitting, deterioration of the stator core 20 due to compressive stress (increase in iron loss) can be avoided. Also, even when shrink fitting is performed, by using the recess 28 to fix the stator 10 to the case 14, the amount of shrink fitting can be reduced due to the fixing force acting by the recess 28. This reduces the compressive stress generated in the stator core 20, and thus reduces the deterioration of the stator core 20 due to iron loss.

[0051] Furthermore, in this embodiment, the connecting portion 24b is integrally molded with a pair of adjacent first yoke components 24a. In this case, sufficient restraining force can be secured between the pair of first yoke components 24a and the connecting portion 24b, thereby enabling sufficiently high rigidity and shape accuracy of the stator core 20.

[0052] Furthermore, in this embodiment, the first connection surface 40 and the second connection surface 60 connecting the first core 24 and the second core 26 are inclined with respect to the radial direction. Therefore, compressive stress is generated in the direction inclined with respect to the radial direction at the joint between the first core 24 and the second core 26. In other words, it is possible to suppress the application of radial compressive stress from the second core 26 to the first core 24. In addition, in the rotating electric machine 100 according to this embodiment, when the stator 10 is inserted into the case 14, the first yoke component 24a and the case 14 come into contact. In this case, radial compressive stress is applied to the first yoke component 24a from the case 14, but since the first yoke component 24a is mainly excited in the circumferential direction, this compressive stress does not pose a problem in terms of iron loss of the stator core 20. On the other hand, compressive stress may also act in the circumferential direction along with the radial compression of the first yoke component 24a, but the circumferential compressive stress tends to concentrate in the connection portion 24b, which has a narrow width in the radial direction. Therefore, an increase in circumferential compressive stress in the first yoke component 24a is suppressed. As a result, the yoke 20a can be excited sufficiently efficiently in the circumferential direction.

[0053] On the other hand, by primarily generating circumferential compressive stress at the connection portion 24b, the compressive stress applied from the case 14 to the second core 26 can be reduced. Furthermore, because the first inclined surface 40a and the second inclined surface 40b are inclined with respect to the reference line L1, the direction of the compressive stress applied from the first core 24 to the second core 26 is limited. This suppresses the generation of radial compressive stress in the second core 26. The teeth 20b are mainly excited in the radial direction, and the portion of the yoke 20a adjacent to the teeth 20b is also easily excited in a direction close to the radial direction. Therefore, by suppressing the radial compressive stress acting in the second core 26 as described above, the teeth 20b and the yoke 20a can be excited efficiently.

[0054] (modified version) Figure 5 shows a modified example of the first core 24. The first core 24 shown in Figure 5 differs from the first core 24 shown in Figure 2 in the following ways. In this embodiment, the connecting portion 24b is divided into a first connecting portion 44a and a second connecting portion 44b by a notch 42 formed on the radially inward side of the connecting portion 24b. The first connecting portion 44a and the second connecting portion 44b are arranged in the circumferential direction on the stator core 20.

[0055] In this embodiment, the notch 42 is formed so that the first connecting portion 44a has a third connecting surface 46a facing the second connecting portion 44b in the circumferential direction, and the second connecting portion 44b has a fourth connecting surface 46b facing the first connecting portion 44a in the circumferential direction and connected to the third connecting surface 46a. The first connecting portion 44a and the second connecting portion 44b are integrally continuous on the outside of the notch 42 in the radial direction (radially outside the third connecting surface 46a and the fourth connecting surface 46b). In the stator core 20, the third connecting surface 46a and the fourth connecting surface 46b are positioned radially outward from the first connecting surface 40.

[0056] In this embodiment, the notch 42 formed in the connecting portion 24b allows the connecting portion 24b to be easily deformed when the first core 24 is curved into an arc shape. Furthermore, the circumferential width of the portion in the first core 24 into which the second core 26 is inserted (the gap between adjacent first yoke components 24a) can be designed to be wider by the width of the notch 42. This makes it easier to attach the second core 26 to the first core 24. When the steel plate (first core 24) deforms, plastic deformation and iron loss deterioration due to residual stress occur in the deformed portion. In this regard, at the outermost periphery of the yoke 20a, there is less excitation at the point located on the straight line extending radially through the center of the teeth 20b in the circumferential direction. In this embodiment, since most of the deformation of the first core 24 is concentrated at this point of less excitation, the amount of iron loss deterioration of the first core 24 due to deformation is extremely small.

[0057] As shown in Figure 6(a), a cylindrical cavity may be formed at the tip of the notch 42. In this embodiment, as shown in Figure 6(b), the notch 42 is formed in the first core 24 such that when the first core 24 is curved into an arc, a cavity 43 is formed on the radially outer side of the third connecting surface 46a and the fourth connecting surface 46b. By forming a notch 42 of this shape, the connecting portion 24b can be smoothly deformed when the first core 24 is curved into an arc.

[0058] Note that the position of the notch is not limited to the above example. For example, as shown in Figure 7, a notch 42 may be formed at the boundary between the connecting portion 24b and the first yoke component 24a in the first core 24.

[0059] In this embodiment, the notch 42 is formed so that a fifth connecting surface 46c is formed at one end of the connecting portion 24b in the circumferential direction, facing the first yoke component 24a in the circumferential direction, and a sixth connecting surface 46d is formed on the first yoke component 24a, facing the fifth connecting surface 46c in the circumferential direction and connected to the fifth connecting surface 46c. The first yoke component 24a and the connecting portion 24b are integrally continuous on the outside of the notch 42 in the radial direction (radially outside the fifth connecting surface 46c and the sixth connecting surface 46d). In the stator core 20, the fifth connecting surface 46c and the sixth connecting surface 46d are positioned radially outward from the first connecting surface 40.

[0060] In this embodiment as well, the formation of the notch 42 allows the connection portion 24b to be easily deformed when the first core 24 is curved into an arc shape. This facilitates the attachment of the second core 26 to the first core 24. In this embodiment as well, a notch with the same shape as the notch 42 shown in Figure 6 may be formed.

[0061] In the above-described embodiment, the case in which the first inclined surface 40a, the second inclined surface 40b, the third inclined surface 60a, and the fourth inclined surface 60b are formed to extend in a straight line when viewed from the axial direction was described. However, the shapes of the first inclined surface 40a, the second inclined surface 40b, the third inclined surface 60a, and the fourth inclined surface 60b are not limited to the above-described example.

[0062] Figure 8 shows other examples of the shapes of the first inclined surface 40a, the second inclined surface 40b, the third inclined surface 60a, and the fourth inclined surface 60b. In addition to the reference line L1, Figure 8 also shows straight lines L6 and L7 parallel to the reference line L1 when viewed from the axial direction. As shown in Figure 8, the first inclined surface 40a, the second inclined surface 40b, the third inclined surface 60a, and the fourth inclined surface 60b may each be formed to curve in an arc shape when viewed from the axial direction. The stator core 20 according to this embodiment also provides the same effects as the stator core 20 described above.

[0063] In the above-described embodiment, the case in which the first connecting surface 40 and the second connecting surface 60 each have two inclined surfaces that are inclined with respect to the reference line L1 was explained. However, the first connecting surface and the second connecting surface may each include a surface that is parallel to the reference line L1 when viewed from the axial direction.

[0064] In the above-described embodiment, a case was explained in which a single first core 24 is curved in an annular shape and used as a component of the stator core 20. However, multiple first cores 24 curved in an arc shape may be connected in an annular shape to form a component of the stator core 20. Alternatively, a part of the stator core may be composed of a strip-shaped first core 24 and multiple second cores 26, while other cores other than the strip-shaped core (deployment core) may be used in the other part of the stator core. For example, in the other part of the stator core, yokes and teeth may be integrally formed. Alternatively, for example, in the other part of the stator core, multiple yoke components that are separated from each other may be provided (a configuration in which only two or more first yoke components 24a are provided in the first core 24 described above, without providing a connecting portion 24b), and second cores 26 may be sandwiched between these yoke components.

[0065] In the above-described embodiment, the circumferential length of the recess 28 is set to be greater than the thickness of the portion of the second yoke component 26a where the thickness is smallest in the circumferential direction. However, as shown in Figure 9, the circumferential length of the recess 28 may be set to be less than the thickness of the portion of the second yoke component 26a where the thickness is smallest in the circumferential direction. Also, although not shown, the circumferential length of the recess 28 may be set to be less than the thickness of the portion of the second yoke component 26a where the thickness is largest in the circumferential direction, and greater than the thickness of the portion of the second yoke component 26a where the thickness is smallest in the circumferential direction.

[0066] Furthermore, in the above-described embodiment, adjacent recesses 28 in the circumferential direction are formed apart from each other, but as shown in Figure 10, adjacent recesses 28 in the circumferential direction may be provided continuously. [Industrial applicability]

[0067] As described above, according to the present invention, a split-type stator core capable of properly fixing the yoke and teeth, and a rotating electric machine equipped therewith, can be obtained. [Explanation of symbols]

[0068] 10 staters 12 rotors 14 cases 20 stator cores 20a York 20b Teeth 22 coils 24. First Core 24a First York Component 24b Connection section 26 Second Core 26a Second York Component 26b Teeth component 28 recesses 30 Coil support section 40 First connection surface 40a 1st slope 40b 2nd slope 50 base yen 60 Second connection surface 60a 3rd slope 60b 4th slope 100 Rotating Electric Machines L1 Reference Line

Claims

1. A split-type stator core having a cylindrical yoke and a plurality of teeth protruding inward from the yoke in the radial direction, It includes a strip-shaped first core and a plurality of second cores fixed to the first core so as to protrude inward from the first core in the radial direction of the yoke, The first core has a plurality of first yoke components that constitute the yoke and are arranged at intervals in the circumferential direction of the yoke, and a plurality of connecting components that connect the radial outer edges of adjacent first yoke components in the circumferential direction. The second core has a second yoke component that constitutes the yoke and is sandwiched between a pair of circumferentially adjacent first yoke components, and a tooth component that constitutes the teeth and protrudes radially inward from the pair of first yoke components. The first yoke component has first connecting surfaces on both sides in the circumferential direction, which are connected to the second yoke component. The second yoke component has second connecting surfaces on both sides in the circumferential direction, which are connected to the first connecting surface of the first yoke component. When viewed from the axial direction of the yoke, if a hypothetical straight line extending radially through the center of the first yoke component in the circumferential direction is defined as the reference line of the first yoke component, the first connecting surface includes a first inclined surface that is inclined with respect to the reference line such that the outer side in the radial direction approaches the reference line in the circumferential direction, and a second inclined surface that is provided radially inward of the first inclined surface and is inclined with respect to the reference line such that the inner side in the radial direction approaches the reference line in the circumferential direction. Viewed from the axial direction, the second connecting surface connected to the first connecting surface of the first yoke component has a third inclined surface and a fourth inclined surface that are inclined with respect to the reference line so as to be aligned with the first inclined surface and the second inclined surface of the first yoke component. The connecting portion has a first connecting portion and a second connecting portion arranged in the circumferential direction, The first connecting portion has a third connecting surface that faces the second connecting portion side in the circumferential direction. The second connecting portion has a fourth connecting surface that faces the first connecting portion side in the circumferential direction and is connected to the third connecting surface. A stator core in which the first and second connecting portions are integrally continuous with respect to the radially adjacent third and fourth connecting surfaces.

2. The aforementioned tooth component has a coil support portion that supports the coil, The stator core according to claim 1, wherein in the circumferential direction, the width of the second yoke component is smaller than the width of the coil support component.

3. The stator core according to claim 1, wherein, when viewed from the axial direction, a virtual circle is defined as the reference circle, centered on the axis of the yoke and circumscribing the plurality of first yoke components, a recess is formed on the radial outer surface of the connecting portion, which is recessed inward in the radial direction compared to the reference circle.

4. The stator core according to claim 1, wherein the connecting portion is integrally molded with the adjacent pair of first yoke components.

5. The stator core according to claim 1, wherein the first core and the plurality of second cores each include a plurality of stacked non-oriented electrical steel sheets.

6. A method for manufacturing a stator having a stator core according to any one of claims 1 to 5, The first core, in its unfolded state, is placed outside the coils arranged in a ring shape. A method for manufacturing a stator, comprising inserting the plurality of second cores sequentially into the coil and the first core from the inside of the coil, while curving the first core along the outer circumference of the coil, thereby attaching the coil and the plurality of second cores to the first core.

7. A stator core according to any one of claims 1 to 5, The coils supported by the plurality of teeth of the stator core, A rotating electric machine comprising a rotor disposed inside the stator core.

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