Stator core portion, stator core, stator, and electric motor

Abstract

This stator core portion includes: an outer circumferential portion extending partially in the circumferential direction of a stator core; and at least one leg part extending in the radial direction of the stator core from the inner circumferential surface of the outer circumferential portion and to which a winding is to be wound. Joining parts that can be joined to each other are provided on one side and the other side of the outer circumferential portion in the circumferential direction. The joining parts that can be joined to each other extend at least partially in an inclined manner with respect to the axial direction of the stator core.

Description

Stator core part, stator core, stator and electric motor

[0001] The present disclosure relates to a stator core portion, a stator core, a stator, and an electric motor.

[0002] When manufacturing a stator for an electric motor, a split core method is sometimes used in which multiple stator core sections, each with a winding wound thereon, are joined together (see, for example, International Publication No. 2023 / 276680). The split core method has the advantages of a high winding space factor and easy winding. Furthermore, less scrap material is required when manufacturing the stator core sections, and the yield is high.

[0003] In the split core method, recesses and protrusions are provided on both circumferential sides of multiple stator core sections, which may be used to join adjacent stator core sections (see, for example, Patent Publication Nos. 2010-178426 and 2007-082275).

[0004] International Publication No. 2023 / 276680 Japanese Patent Application Laid-Open No. 2010-178426 Japanese Patent Application Laid-Open No. 2007-082275

[0005] However, after a stator core is created using the split core method, if a force acting radially outward is applied to the stator core, the multiple stator core sections may separate from one another. For this reason, after the stator is created by winding the windings around the stator core, the stator must be inserted into a casing using shrink fitting or press fitting to secure the multiple stator core sections.

[0006] However, using a casing increases manufacturing costs and the number of manufacturing steps, and inserting the stator into the casing reduces heat dissipation and increases core iron loss due to stress, resulting in increased motor losses.

[0007] Therefore, what is desired is a stator core section that can be joined together without the need for a casing, as well as a stator core, a stator, and an electric motor using such a stator core section.

[0008] According to a first aspect of the present disclosure, there is provided a stator core part including an outer peripheral part extending partially in the circumferential direction of the stator core, at least one leg extending from an inner peripheral surface of the outer peripheral part in the radial direction of the stator core and around which a winding is to be wound, and joints that can be joined to each other are provided on one and the other sides of the outer peripheral part in the circumferential direction, and the joints that can be joined to each other extend at least partially at an angle with respect to the axial direction of the stator core.

[0009] The objects, features, and advantages of the present disclosure will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings.

[0010] 1. An axial cross-sectional view of an electric motor according to the present disclosure. 2. A top view of a stator core according to a first embodiment. 3. A top view of a stator core portion according to the first embodiment. 4. A perspective view of the stator core portion shown in FIG. 3A. 5. A perspective view showing a manufacturing method of the stator core shown in FIG. 2. 6. A partial enlarged view of FIG. 4A. 7. A partial enlarged view of the stator core portion. 8. Another axial cross-sectional view of an electric motor. 9. An enlarged view of a first example of a side surface of an outer circumferential portion. 10. An enlarged view of a second example of a side surface of an outer circumferential portion. 11. An enlarged view of a third example of a side surface of an outer circumferential portion. 12. A top view of a stator core portion according to a second embodiment. 13. A perspective view of a stator core portion according to a third embodiment. 14. A top view of a stator core portion according to a fourth embodiment. 15. A perspective view of the stator core portion shown in FIG. 6A. 16. A side view of an inner diameter jig. 17. A perspective view of a stator core according to a second embodiment. 18. A perspective view of a stator core according to a third embodiment. 19. A top view of a stator core portion according to a fourth embodiment. 12B is a perspective view of the stator core portion shown in FIG. 12A; FIG. 12C is a partially enlarged view of the stator core according to the fourth embodiment; FIG.

[0011] Embodiments of the present disclosure will now be described with reference to the accompanying drawings. Corresponding components are designated by common reference numerals throughout the drawings. FIG. 1 is an axial cross-sectional view of an electric motor based on the present disclosure. As shown in FIG. 1, the electric motor 1 includes a stator 10 having a plurality of windings 6, and a rotor 9 rotatably supported on the stator 10 by a first bearing 7 and a second bearing 8. A shaft 5 passing through the rotor 9 is rotatably supported on the stator 10 by the first bearing 7 and the second bearing 8.

[0012] As shown in the figure, both ends of the winding 6 in the axial direction of the electric motor 1 protrude from both end faces of the stator 10. To protect the protruding portions of the winding 6, a first flange 3 may be provided at one end of the stator 10, and a second flange 4 may be provided at the other end of the stator 10. The first bearing 7 and the second bearing 8 are preferably included within the first flange 3 and the second flange 4, respectively. However, the first bearing 7 and the second bearing 8 may also be disposed on the inner circumferential surface of the stator 10. An electrical connector (not shown) may also be provided on one of the flanges 4. As will be described later, no casing is provided around the stator 10 in this disclosure.

[0013] FIG. 2 is a top view of a stator core according to the first embodiment. The stator core 10a is the stator 10 described above without the windings 6. The stator core 10a is configured by arranging a plurality of, for example, twelve identically shaped stator core portions 21a to 21l adjacent to one another in the circumferential direction. An opening is formed in the center of the stator core 10a in which the rotor 9 described above is disposed. In the following description, the terms "circumferential direction," "radial direction," and "axial direction" refer to the circumferential direction, radial direction, and axial direction of the stator cores 10a to 10d, respectively, unless otherwise specified.

[0014] Figure 3A is a top view of a stator core portion based on the first embodiment. While Figure 3A shows stator core portion 21a as a representative example, the other stator core portions 21b to 21l are assumed to have a similar shape. Stator core portion 21a includes an outer peripheral portion 22 that corresponds to a portion of the outer periphery of stator 10. Therefore, outer peripheral portion 22 extends partially in the circumferential direction of stator core 10a.

[0015] Furthermore, the stator core portion 21a mainly includes a leg portion 23 extending radially inward of the stator 10 from the inner circumferential surface of the outer circumferential portion 22. In the first embodiment, each of the stator core portions 21a to 21l includes a single leg portion 23. The aforementioned winding 6 can be wound around the leg portion 23.

[0016] 3A, the stator core portion 21a further has flanges 24a and 24b extending from the tips of the legs 23 in a direction substantially parallel to the outer circumferential portion 22. The flanges 24a and 24b extend in opposite directions from the tips of the legs 23. The flanges 24a and 24b serve to hold the windings 6.

[0017] The outer peripheral portion 22 has side surfaces 22a and 22b that face each other in the circumferential direction. A first bonding portion 31 and a second bonding portion 32 are provided on the side surfaces 22a and 22b, respectively. In this specification, the first bonding portion 31 and the second bonding portion 32 that are adjacent to each other may be collectively referred to as a bonding portion 30.

[0018] In a typical embodiment, the first bonding portion 31 is a convex portion, and the second bonding portion 32 is a concave portion that can be bonded to the first bonding portion 31. However, the first bonding portion 31 and the second bonding portion 32 may have other shapes that can be bonded to each other.

[0019] 3B is a perspective view of the stator core portion shown in FIG. 3A. As can be seen from FIG. 3A and FIG. 3B, the second joint portion 32 as a recess on the side surface 22b extends at a predetermined angle relative to the axial direction of the stator core 10a. In other words, the second joint portion 32 is inclined radially outward in the direction from top to bottom of the stator core 10a.

[0020] 3B , one end 32 a of the second joint portion 32 is located on the upper end surface of the outer circumferential portion 22, and the other end 32 b of the second joint portion 32 is located on the lower end surface of the outer circumferential portion 22. The one end 32 a of the second joint portion 32 is located radially inward of the stator core 10 a relative to the other end 32 b of the second joint portion 32. In an embodiment described later, the second joint portion 32 may be inclined with respect to the axial direction and formed only partially on a line segment connecting the upper end surface and the lower end surface of the outer circumferential portion 22.

[0021] 3A and 3B , the first joint portion 31 serving as a protrusion extends at a predetermined angle relative to the axial direction of the stator core 10a. This predetermined angle is equal to the predetermined angle of the second joint portion 32. In the configuration shown in FIG. 3B , one end 31a of the first joint portion 31 located on the upper end surface of the outer circumferential portion 22 is located radially inward of the stator core 10a relative to the other end 31b of the first joint portion 31 located on the lower end surface of the outer circumferential portion 22.

[0022] Furthermore, the first bonding portions 31 formed on the side surfaces 22a of the outer peripheral portion 22 may have a length equal to or shorter than that of the corresponding second bonding portions 32. For example, while the second bonding portions 32 extend from the upper end face to the lower end face of the outer peripheral portion 22, the first bonding portions 31 may be formed only partially on a line segment extending from the upper end face to the lower end face of the outer peripheral portion 22.

[0023] Fig. 4A is a perspective view showing a manufacturing method of the stator core shown in Fig. 2, and Fig. 4B is a partially enlarged view of Fig. 4A. Fig. 4B shows one stator core portion 21a and another stator core portion 21b adjacent to the stator core portion 21a on the first joint portion 31 side. Then, the stator core portion 21b is slid radially outward from above to below relative to the stator core portion 21a. The sliding direction is indicated by arrow A, and this direction corresponds to the predetermined angle described above.

[0024] By sliding the stator core portion 21b relative to the stator core portion 21a as described above, the first joint portion 31 of the stator core portion 21a and the second joint portion 32 of the stator core portion 21b can be easily joined together. The other stator core portions 21c to 21l are then joined together in the circumferential direction in the same manner, thereby forming the stator core 10a (see FIG. 4A).

[0025] Here, Figure 5A is a partial enlarged view of the side surface 22b of the stator core portion. The direction from left to right in Figure 5A corresponds to the radially outward direction. In the present disclosure, the second joint portion 32 and the first joint portion 31 are inclined at a predetermined angle with respect to the axial direction. Therefore, after the stator core 10a is assembled, when a force F0 acts radially outward, the force F0 is converted into a component force F1 extending perpendicular to the second joint portion 32 and a component force F2 along the second joint portion 32.

[0026] The component forces F1 and F2 each include a force in the axial direction of the stator core 10a. Therefore, even if force F0 acts radially outward after the stator core 10a is assembled, it is possible to prevent adjacent stator core portions, for example, stator core portion 21a and stator core portion 21b, from separating from each other. Therefore, in the present disclosure, it is possible to eliminate the need to insert the stator 10 into a casing, as shown in FIG. 1.

[0027] Since the present disclosure does not require a casing, manufacturing costs and man-hours can be reduced. Also, since the stator 10 of the electric motor 1 shown in FIG. 1 is not inserted into a casing, heat dissipation is not reduced when the electric motor 1 is running. Furthermore, in the electric motor 1 of the present disclosure, the core iron loss value does not increase due to stress, and as a result, there is an effect that the loss of the electric motor does not increase.

[0028] 2 and 4A, a through hole 2a extending in the axial direction is formed in the outer peripheral portion 22 of some of the stator core portions, for example, the stator core portions 21b, 21e, 21h, and 21k. Similar through holes are formed in the first flange 3 and the second flange 4 at corresponding positions.

[0029] The first flange 3 and the second flange 4 are disposed at the upper and lower ends of the stator 10, which has the windings 6 wound around the legs 23 of the stator core 10a. Next, a rod-shaped member 2, such as a bolt or rod, is inserted into the through-hole 2a. Finally, the first flange 3, the stator 10, and the second flange 4 are fixed in the axial direction using a known method.

[0030] This prevents the stator core portions 21a to 21l from being misaligned in the axial direction, further reducing the possibility that the stator core portions 21a to 21l will be separated from one another. Alternatively, the through holes 2a may be formed in all of the stator core portions 21a to 21l.

[0031] FIG. 5B is another axial cross-sectional view of the motor. In FIG. 5B, the first flange 3 and the second flange 4 are not provided on the stator 10. Furthermore, through holes 2a are not formed in any of the stator core portions 21a to 21l. Furthermore, both end surfaces of the stator 10 are covered with molded resin 11. In this case, the stator core portions 21a to 21l are not displaced in the axial direction, and therefore, the stator core portions 21a to 21l are not separated from one another. In this case, it can be seen that the same effect as described above can be obtained without the need for the first flange 3 and the second flange 4. As can be seen from FIG. 5B, in order to improve heat dissipation, it is preferable that the outer peripheral surface of the stator 10 is not covered with molded resin 11. Alternatively, the inner peripheral surface of the stator 10 may be covered with molded resin 11. Furthermore, a case in which both end surfaces of the stator 10 are not covered with molded resin 11, and only the inner peripheral surface of the stator 10 is covered with molded resin, is also within the scope of the present disclosure.

[0032] 5C to 5F are enlarged views of first to fourth examples of the side surface 22b of the outer peripheral portion 22. In these drawings, the right side shows the radially outer side of the stator core 10a, and the left side shows the radially inner side of the stator core 10a.

[0033] 5C is a view generally similar to the side surface 22b of the stator core portion 21a shown in Fig. 4B, in which the second joint portion 32 extends parallel to the diagonal line of the side surface 22b from the upper end to the lower end of the outer peripheral portion 22. Note that the second joint portion 32 in Fig. 5C, Fig. 5E, and Fig. 5F may extend at a different angle with respect to the axial direction.

[0034] The second joint portion 32 shown in Fig. 5D extends along the diagonal line of the side surface 22b from the upper end to the lower end of the outer peripheral portion 22. Furthermore, the second joint portion 32 shown in Fig. 5E extends parallel to the diagonal line of the side surface 22b from the upper end of the side surface 22b to the outer peripheral surface of the outer peripheral portion 22. In Fig. 5C, 5D, and 5E, as described above, the other stator core portion 21b is slid radially outward from above to below relative to the stator core portion 21a, thereby joining the stator core portions 21a and 21b to each other.

[0035] 5F extends parallel to the diagonal of the side surface 22b from the inner peripheral surface of the outer peripheral portion 22 to the lower end of the side surface 22b. In this case, the other stator core portion 21b is slid radially inward from below to above the stator core portion 21a, thereby joining the stator core portions 21a and 21b to each other.

[0036] In this way, in order to join the stator core portions 21a, 21b to each other by the sliding action thereof, one of the one end 32a and the other end 32b of the second joint portion 32 needs to be located at the upper end or the lower end of the outer circumferential portion 22. In contrast, if neither the one end 32a nor the other end 32b of the second joint portion 32 is located at either the upper end or the lower end of the outer circumferential portion 22, the last stator core portion 21l cannot be joined to the other stator core portions 21a, 21k when assembling the stator core 10a.

[0037] 5C to 5F, the second joint portion 32 is sufficient to have a length of at least one-third of the overall length shown in Figures 5C to 5F, and the stator core portions 21a to 21l will not separate from one another after the stator core 10a is assembled. However, even in this case, one of the ends 32a and 32b of the second joint portion 32 must be located at the upper or lower end of the outer peripheral portion 22. The first joint portion 31 may be formed to a length equal to or shorter than the second joint portion 32. However, even in this case, it is preferable that the first joint portion 31 have a length of at least one-third of the overall length described above.

[0038] Each of the stator core portions 21a to 21l can be made by stacking multiple magnetic plates, such as iron plates, carbon steel plates, and electromagnetic steel plates. In this case, multiple magnetic plates are stacked such that the positions of the portions corresponding to the first joint 31 and the second joint 32 are slightly different.

[0039] Alternatively, each of the stator core portions 21a to 21l may be formed from a powder iron core. Furthermore, the first joint portion 31 and the second joint portion 32 may be formed by cutting the side surfaces 22a and 22b of a stator core portion that is made to be a predetermined length in the circumferential direction. This is also true for other embodiments.

[0040] Fig. 6A is a top view of a stator core portion 21a based on the second embodiment, and Fig. 6B is a perspective view of the stator core portion 21a shown in Fig. 6A. The main difference between the first embodiment and the second embodiment is that grooves 25a, 25b extending parallel to the axial direction of the stator core 10a are formed on the inner circumferential surfaces of the flanges 24a, 24b. The grooves 25a, 25b serve to suppress cogging torque when the electric motor 1 is driven.

[0041] Furthermore, Fig. 7 is a side view of the inner diameter jig, and Fig. 8 is a perspective view of a stator core 10b based on the second embodiment. The inner diameter jig 40 has a truncated cone shape having a substantially circular upper surface 41 and a substantially circular lower surface 42 that is larger than the upper surface 41. A plurality of protrusions 45 are provided on the side surface of the inner diameter jig 40. These protrusions 45 extend from the upper surface 41 to the lower surface 42 of the inner diameter jig 40. The spacing between these protrusions 45 matches the spacing between the grooves 25a and 25b. In other words, the multiple protrusions 45 are formed so as to be engageable with 25a, 25b on the inner circumferential surface of the stator core 10b consisting of the stator core portions 21a to 21l.

[0042] Fig. 8 is a perspective view of a stator core according to the second embodiment. In Fig. 8, after the stator core 10b is produced, or during the production of the stator core 10b, an inner diameter jig 40 is inserted into the center of the stator core 10b.

[0043] As described above, the protrusions 45 of the inner diameter jig 40 engage with the grooves 25b and the stator core portions 21a, etc. 25a. Therefore, the roundness of the stator core 10b can be easily improved by using the inner diameter jig 40. Naturally, the inner diameter jig 40 is removed after the stator core 10b is formed.

[0044] Fig. 9 is a perspective view of a stator core 10c based on the third embodiment, and Fig. 10 is a top view of the stator core 10c shown in Fig. 9. The stator core 10c is configured by joining a plurality of, for example, four identical stator core portions 51a to 51d adjacent to each other in the circumferential direction. An opening similar to that described above is formed in the center of the stator core 10c.

[0045] Figure 11A is a top view of a stator core portion based on the third embodiment, and Figure 11B is a perspective view of the stator core portion shown in Figure 11A. While Figures 11A and 11B show stator core portion 51a as a representative example, the other stator core portions 51b to 51d are assumed to have a similar shape. Stator core portion 51a mainly includes an outer peripheral portion 52 corresponding to a portion of the outer periphery of stator 10, and multiple (e.g., three) legs 53a, 53b, and 53c extending radially inward of stator 10 from the inner circumferential surface of outer peripheral portion 52. The aforementioned windings 6 can be wound around these legs 53a, 53b, and 53c, respectively.

[0046] 11A, the stator core portion 51a further includes flanges 54a and 54b extending in a substantially circumferential direction from the tips of the legs 53a, 53b, and 53c, respectively. The flanges 54a and 54b extend in opposite directions from the tips of the legs 53a, 53b, and 53c. As described above, the flanges 54a and 54b serve to hold the windings 6.

[0047] Further, grooves 55a and 55b extending parallel to the axial direction of the stator core are formed on the inner peripheral surfaces of the flanges 54a and 54b of the legs 53a, 53b, and 53c, respectively. As described above, the grooves 55a and 55b serve to suppress cogging torque when the electric motor 1 is driven. Furthermore, when the inner diameter jig 40 is inserted into the stator core, the grooves 55a and 55b engage with the protrusions 45 of the inner diameter jig 40 as described above.

[0048] In the third embodiment, the stator core 10c is also produced by joining the first joint portion 31 and the second joint portion 32 as described above. As shown in the figure, at least one through-hole 2b is formed in the axial direction in the outer peripheral portion 52 of each of the stator core portions 51a to 51d. Then, the first flange 3, the stator 10, and the second flange 4 are fixed as described above by passing the rod-shaped members 2 through these through-holes 2b.

[0049] Alternatively, since the outer peripheral surface of the outer peripheral portion 22 has a notch 29, the rod-shaped member 2 may be disposed at a position 2c corresponding to the notch 29, and the first flange 3, the stator 10, and the second flange 4 may be fixed as described above. Alternatively, the entire stator 10 may be covered with the molded resin 11 without using the first flange 3, the second flange 4, etc. In such a case, it is not necessary to form the through-hole 2b in each of the stator core portions 51a to 51d.

[0050] It is clear that even when one stator core portion 51 a has a plurality of legs 53 a, 53 b, 53 c in this way, substantially the same effect as that described above can be obtained. Furthermore, the third embodiment has the advantage of being able to reduce the number of parts required to form the stator core 10 c.

[0051] Fig. 12A is a top view of a stator core portion based on the fourth embodiment, and Fig. 12B is a perspective view of the stator core portion shown in Fig. 12A. The stator core portion 21a shown in these drawings has a first joint portion 31' and a second joint portion 32' on side surfaces 22a and 22b, respectively. The first joint portion 31' is a convex portion having a different shape from the first joint portion 31 described above, and the second joint portion 32' is a concave portion having a different shape from the second joint portion 32 described above.

[0052] Fig. 12C is a partially enlarged view of the stator core according to the fourth embodiment, and Fig. 12D is a top view of the stator core according to the fourth embodiment. As shown in Fig. 12C, the axial cross section of the first joint portion 31' as a protrusion is composed of a substantially trapezoidal portion 33a extending from the side surface 22a and a substantially circular portion 33b partially overlapping the substantially trapezoidal portion 33a. A narrow portion 33c is formed between the trapezoidal portion 33a and the circular portion 33b. As can be seen from Fig. 12C, the length of the narrow portion 33c in a direction parallel to the side surfaces 22a and 22b is shorter than the maximum lengths of the trapezoidal portion 33a and the circular portion 33b in the same direction.

[0053] The second joining portion 32' has a shape that allows it to be joined to the first joining portion 31', and therefore the second joining portion 32' has portions that correspond to the approximately trapezoidal portion 33a, the circular portion 33b, and the narrow portion 33c.

[0054] Then, by joining the stator core portions 21a to 21l together as described above, the stator core 10d shown in Figure 12D is produced. When the first joint portion 31' and the second joint portion 32' have the narrow width portion 33c in this manner, the stator core portions 21a to 21l do not separate from each other in the circumferential direction. Therefore, the stator core 10d is less likely to separate than the stator cores 10a to 10c described above, and therefore the need for a casing can be further eliminated.

[0055] In an embodiment not shown, the first bonding portion 31 may be a combination of a recess and a protrusion, and the second bonding portion 32 may be a combination of a corresponding protrusion and a recess. Such a case is also within the scope of the present disclosure.

[0056] As an advantage of at least one of the embodiments described above, multiple stator core sections can be joined together without the need for a casing, so that heat dissipation is not reduced and loss in the motor 1 is not increased when the motor 1 including the stator core sections is in operation.

[0057] Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the invention or the concept and spirit of the present invention derived from the content of the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical formulas are used in the description of the above-described embodiments. Furthermore, appropriate combinations of several of the above-described embodiments are within the scope of the present disclosure.

[0058] The following supplementary notes are further disclosed regarding the above embodiments and variations. (Supplementary Note 1) A stator core part comprising: an outer circumferential portion extending partially in the circumferential direction of a stator core; at least one leg extending from an inner circumferential surface of the outer circumferential portion in the radial direction of the stator core, the leg being around which a winding is to be wound; and joinable joints provided on one and the other sides of the outer circumferential portion in the circumferential direction, the joinable joints extending at least partially at an angle with respect to the axial direction of the stator core. (Supplementary Note 2) The stator core part according to Supplementary Note 1, one of the joinable joints being formed on one side of the outer circumferential portion, and the other of the joinable joints being formed on the other side of the outer circumferential portion. (Supplementary Note 3) The stator core part according to Supplementary Note 1, the joinable joints extending at least partially on a line segment connecting one end and the other end of the outer circumferential portion in the axial direction of the stator core. (Supplementary Note 4) The stator core parts according to Supplementary Note 1, wherein the joinable joints are a combination of convex and concave portions. (Supplementary Note 5) A stator core configured by joining a plurality of stator core parts according to Supplementary Note 1 in the circumferential direction. (Supplementary Note 6) The stator core according to Supplementary Note 5, wherein a flange extending partially in the circumferential direction of the stator core is provided at a tip of the at least one leg part on the radially inner side of the stator core, and a groove extending parallel to the axial direction of the stator core is formed on an inner peripheral surface of the flange. (Supplementary Note 7) A stator comprising windings wound around a plurality of the at least one leg parts of the stator core according to Supplementary Note 5. (Supplementary Note 8) The stator according to Supplementary Note 7, comprising flanges arranged at one end and the other end of the axial direction of the stator. (Supplementary Note 9) An electric motor comprising the stator according to Supplementary Note 8 and a rotor arranged radially inside the stator.

[0059] DESCRIPTION OF SYMBOLS 1 Electric motor 2 Rod-shaped member 2a, 2b Through hole 3 First flange 4 Second flange 5 Shaft portion 6 Winding 7 First bearing 8 Second bearing 9 Rotor 10 Stator 10a to 10d Stator core 11 Molded resin 21a to 21l Stator core portion 22 Outer periphery 22a, 22b Side surface 23 Leg portion 24a, 24b Flange portion 25a, 25b Groove portion 29 Notch portion 30 Joint portion 31, 31' First joint portion 31a One end 31b Other end 32, 32' Second joint portion 32a One end 32b Other end 33a Approximately trapezoidal portion 33b Circular portion 41 Upper surface 42 Lower surface 51a to 51d Stator core portion 53a, 53b, 53c Legs 54a, 54b Flange 55a, 55b Groove

Claims

1. A stator core part comprising: an outer peripheral portion extending partially in the circumferential direction of a stator core; at least one leg extending from the inner peripheral surface of the outer peripheral portion in the radial direction of the stator core and around which a winding is to be wound; and joints that can be joined to each other provided on one and the other sides of the outer peripheral portion in the circumferential direction, the joints that can be joined to each other extending at least partially at an angle to the axial direction of the stator core.

2. A stator core portion according to claim 1, wherein one of the joints that can be joined to each other is formed on one side of the outer peripheral portion, and the other of the joints that can be joined to each other is formed on the other side of the outer peripheral portion.

3. A stator core portion according to claim 1, wherein the joint portions that can be joined together extend at least partially on a line segment connecting one end and the other end of the outer peripheral portion in the axial direction of the stator core.

4. The stator core portion according to claim 1, wherein the joinable joints are a combination of convex and concave portions.

5. A stator core according to claim 1, which is constructed by joining a plurality of stator core sections in the circumferential direction.

6. A stator core as set forth in claim 5, wherein a flange portion extending partially in the circumferential direction of said stator core is provided at the tip of said at least one leg portion on the radially inner side of said stator core, and a groove portion extending parallel to the axial direction of said stator core is formed on the inner peripheral surface of said flange portion.

7. A stator comprising a plurality of windings wound around said at least one leg of the stator core according to claim 5.

8. A stator according to claim 7, further comprising flanges disposed at both ends of the stator in the axial direction.

9. An electric motor comprising the stator according to claim 8 and a rotor disposed radially inside the stator.

Images