JP2017163667A - Stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator capable of preventing a plate from floating or curling while ensuring the efficiency of the rotary electric machine.SOLUTION: The stator includes: a split core 21 laminated with a plate 22 having a magnetism; a stator core 11 including a plurality of split cores 21 which are arranged to form a cylindrical shape; and a holder 12 mated with the stator core 11. The stator core 11 is mated with the holder 12 therein in a state that, in at least the end parts in an axial direction thereof, the outer periphery surface thereof facing to the outside in a radial direction at both end parts of the split cores 21 in a circumferential direction are separated from the inner peripheral surface of the holder 12 in the radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stator.

  In some stator cores of rotating electrical machines used for vehicle driving, regenerative power generation, and the like, a plurality of divided cores are arranged in the circumferential direction and formed into a cylindrical shape. Each divided core is configured by stacking magnetic plates in the axial direction. The plates adjacent in the axial direction are connected by caulking or the like.

  By the way, the above-described stator core is fitted into the holder by press fitting or the like in a state where a plurality of divided cores are arranged in a cylindrical shape, for example. At this time, there is a possibility that the plate located at the end portion in the axial direction of the split core may be lifted or turned up by a load acting between the stator core and the holder or between the split cores adjacent in the circumferential direction.

Therefore, for example, in Patent Document 1 below, among the plates constituting the split core, the caulking location between the plates located at the end in the axial direction is compared with the caulking location between the plates located at the central portion in the axial direction. More configurations are disclosed.
According to this configuration, the plates positioned at the end portions in the axial direction can be firmly connected to each other, so that it is considered that the floating and turning of the plates can be suppressed.

JP 2011-125141 A

  However, in the configuration of Patent Document 1 described above, there are fears that iron loss may increase due to eddy currents generated at the caulking location due to an increase in caulking locations between the plates positioned at the end in the axial direction. As a result, the efficiency of the rotating electrical machine may be reduced.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a stator capable of suppressing the lift and turn-up of a plate while suppressing a decrease in the efficiency of a rotating electrical machine.

  In order to achieve the above object, the invention described in claim 1 includes a split core (for example, the split core 21 in the embodiment) in which magnetic plates (for example, the plate 22 in the embodiment) are stacked, A stator core (for example, the stator core 11 in the embodiment) in which the divided cores are arranged and formed in a cylindrical shape, and a holder (for example, the holder 12 in the embodiment) to which the stator core is fitted, are provided. And at least both ends of the split core in the circumferential direction are spaced from the inner circumferential surface of the holder in the radial direction of the outer circumferential surface facing the outside in the radial direction at least at the end in the axial direction. Are combined.

  In the invention described in claim 2, a portion of the outer peripheral surface of the divided core facing outward in the radial direction that avoids both ends in the circumferential direction protrudes outward in the radial direction, and the holder The protrusion part (for example, protrusion part 41 in embodiment) which contacts the inner peripheral surface of this may be formed.

  In the invention described in claim 3, the back yoke piece extending in the circumferential direction (for example, the back yoke piece 24 in the embodiment) and the radially inner portion of the back yoke piece project inward in the radial direction. A tooth portion (for example, the tooth portion 14 in the embodiment), and the protruding portion may be formed on a portion of the outer peripheral surface of the back yoke piece that overlaps the tooth portion when viewed from the radial direction. Good.

  In the invention described in claim 4, the split core includes a back yoke piece extending in the circumferential direction, and a teeth portion protruding inward in the radial direction from a central portion in the circumferential direction of the back yoke piece. The back yoke piece is formed with a caulking portion (for example, the caulking portion 33 in the embodiment) for connecting the plates adjacent in the axial direction, and the protruding portion is formed on the outer peripheral surface of the back yoke piece. Of these, it may be formed at a position overlapping the caulking portion when viewed from the radial direction.

  In the invention described in claim 5, the protrusion is formed in an arc shape convex toward the outside in the radial direction in a plan view seen from the axial direction, and the curvature radius of the protrusion is the It may be smaller than the radius of curvature of the inner peripheral surface.

  In the invention described in claim 6, the protruding portion may be in contact with the inner peripheral surface of the holder in the radial direction over the entire axial direction of the divided core.

  In the invention described in claim 7, a portion of the divided core that avoids both axial end portions protrudes outward in the radial direction and contacts with an inner peripheral surface of the holder (for example, In the embodiment, the projecting portion 541) is formed, and the divided core may have the entire outer peripheral surface facing the radially outer side at both end portions in the axial direction separated from the inner peripheral surface of the holder.

According to the first aspect of the present invention, the boundary portion between the divided cores adjacent in the circumferential direction and the fitting portion of the holder in the divided core can be separated in the circumferential direction. Thereby, it can suppress that the plate | board located in the edge part of an axial direction among division | segmentation cores generate | occur | produces by the load which acts between a division | segmentation core and a holder at the time of a fitting.
In particular, since there is no need to increase the number of caulking locations as in the prior art, an increase in iron loss can be suppressed and a reduction in efficiency of the rotating electrical machine can be suppressed.

  According to the second aspect of the present invention, since the protruding portion is formed on the outer peripheral surface of the split core at a portion that avoids both end portions in the circumferential direction, the load acting between the protruding portion and the holder is reduced. It becomes easy to secure easily, and the split core can be securely held in the holder.

  According to the third aspect of the present invention, since the projecting portion is a central portion in the circumferential direction of the back yoke piece and is formed at a position overlapping with the teeth portion when viewed from the radial direction, it is adjacent in the circumferential direction. A distance between a boundary portion between the divided cores and a fitting portion of the holder in the divided core can be secured. Therefore, it is possible to reliably suppress the occurrence of plate lifting and turning.

According to the invention described in claim 4, the protruding portion is arranged at a position close to the crimping portion in the split core, in which the connection strength between the adjacent plates in the axial direction is relatively high. Thereby, it is possible to reliably prevent the plate from being lifted or turned up due to a load or the like acting between the holder and the protruding portion during fitting.
The caulking portion is generally formed in a portion of the divided core that is less affected by the magnetic circuit. Therefore, by forming the protruding portion at a position overlapping the caulking portion as viewed from the side as viewed from the radial direction, the influence of the magnetic circuit due to the load acting between the holder and the protruding portion can be reduced as much as possible.

  According to the fifth aspect of the present invention, since the outer peripheral surface of the protrusion and the inner peripheral surface of the holder are in contact with each other on the curved surface, the protrusion is prevented from being caught on the inner peripheral surface of the holder, and the floating of the plate is stopped. It is possible to reliably suppress the occurrence of cracks and the like.

According to the invention described in claim 6, since the protruding portion is formed over the entire axial direction of the split core, the entire axial direction of the stator core can be stably held in the holder.
Moreover, since the same shape and same size plate can be used over the whole axial direction in a division | segmentation core, cost reduction can be achieved.

  According to the invention described in claim 7, both end portions in the axial direction of the outer peripheral surfaces of the divided cores are separated from the inner peripheral surface of the holder in the radial direction over the entire circumferential direction. The floating and turning of the plate at the axial end of the split core can be reliably suppressed.

It is a fragmentary top view of the stator which concerns on 1st Embodiment. It is a partial top view of the stator which concerns on 2nd Embodiment. It is a fragmentary top view of the stator which concerns on 3rd Embodiment. It is a fragmentary top view of the stator which concerns on 4th Embodiment. It is a fragmentary sectional view of the stator concerning a 5th embodiment. It is a fragmentary top view of the stator which concerns on 5th Embodiment. It is a fragmentary top view of the stator which concerns on the other structure of embodiment.

Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a partial plan view of the stator 1.
As shown in FIG. 1, the stator 1 of this embodiment is mounted on a rotating electrical machine used for vehicle driving and regenerative power generation such as an electric vehicle and a hybrid vehicle. The rotating electrical machine is configured such that a rotor (not shown) is rotatably arranged inside the stator 1. The rotor is connected to the axle of the vehicle through a speed reduction mechanism or the like so that power can be transmitted.

  The stator 1 includes a cylindrical stator core 11 and a holder 12 into which the stator core 11 is press-fitted. In the following description, a direction along the axis of the stator core 11 may be simply referred to as an axial direction, a direction orthogonal to the axis may be referred to as a radial direction, and a direction around the axis may be referred to as a circumferential direction.

The stator core 11 has a cylindrical back yoke portion 13 and a teeth portion 14 projecting radially inward from the back yoke portion 13.
The stator core 11 described above is formed by arranging a plurality of divided cores 21 in the circumferential direction. The split core 21 is configured by laminating magnetic plates 22 (electromagnetic steel plates) punched by pressing or the like in the axial direction. In the present embodiment, each plate 22 is formed in the same shape and size. Each divided core 21 is formed with an equivalent configuration.

  The split core 21 is formed in a T shape in a plan view viewed from the axial direction. Specifically, each divided core 21 includes a back yoke piece 24 and the above-described tooth portion 14 that protrudes radially inward from the back yoke piece 24.

The back yoke piece 24 constitutes a part of the circumferential direction in the back yoke portion 13 of the stator core 11. The back yoke piece 24 has a base portion 31 located at the center portion in the circumferential direction, and a pair of flange portions 32 projecting on both sides in the circumferential direction with respect to the base portion 31. Of the back yoke piece 24, the outer peripheral surface (the surface facing the outer side in the radial direction) of the flange portion 32 is formed in an arc shape in a plan view as viewed from the axial direction.
The split cores 21 adjacent in the circumferential direction are arranged in a state in which end faces facing each other in the circumferential direction of the back yoke piece 24 (the flange portion 32) are abutted with each other. Each flange portion 32 of the back yoke piece 24 is formed with a caulking portion 33 for connecting the plates 22 adjacent in the axial direction. Note that the shape, position, number, and the like of the crimping portion 33 can be changed as appropriate. However, the crimping portion 33 is preferably formed in a portion of the divided core 21 where the amount of magnetic flux passing is small (a portion where the magnetic circuit influence is small).

  One tooth portion 14 is provided for each divided core 21. The teeth portion 14 is provided so as to project from the inner peripheral surface (the surface facing the inner side in the radial direction) of the base portion 31 of the back yoke piece 24 toward the inner side in the radial direction. That is, the above-described flange portion 32 in the back yoke piece 24 is a portion that protrudes on both sides in the circumferential direction with respect to the tooth portion 14. A coil (not shown) is attached to the tooth portion 14 via an insulator (not shown). Note that a plurality of tooth portions 14 may be provided for one divided core 21.

  Here, on the outer peripheral surface of the base portion 31 (the surface facing the outer side in the radial direction) of the back yoke piece 24 described above, a protruding portion 41 protruding toward the outer side in the radial direction is formed. The protruding portion 41 is a portion of the back yoke piece 24 that is located closer to the center portion in the circumferential direction than the above-described crimping portion 33, and is disposed at the same position in the circumferential direction as the above-described tooth portion 14. Accordingly, the protruding portion 41 is disposed at a position that does not overlap the crimping portion 33 in a side view as viewed from the radial direction. In the example of FIG. 1, the circumferential width of the protruding portion 41 is equal to that of the base portion 31 (the teeth portion 14). However, the width and the like of the protruding portion 41 can be changed as appropriate.

  The outer peripheral surface of the protrusion 41 is formed in an arc shape that follows the inner shape of the holder 12. Further, both end edges in the circumferential direction of the protruding portion 41 are connected to the outer peripheral surface of the flange portion 32 through a step surface 42 extending in the radial direction.

The holder 12 is formed in a cylindrical shape arranged coaxially with the stator core 11. The inner diameter of the holder 12 is smaller than the portion (maximum outer diameter portion) where the protruding portion 41 is located in the stator core 11 and larger than the portion other than the protruding portion 41 (minimum outer diameter portion). That is, a portion of the stator core 11 where the protruding portion 41 is located is provided with a fastening allowance between the holder 12 and the portion.
The stator core 11 is press-fitted into the holder 12 with the inner peripheral surface of the holder 12 and the outer peripheral surface of the protruding portion 41 of each divided core 21 in contact with each other. On the other hand, in the stator core 11, the outer peripheral surface of the flange portion 32 in each divided core 21 is spaced from the inner peripheral surface of the holder 12 in the radial direction. Therefore, the boundary portion between the divided cores 21 adjacent in the circumferential direction is spaced from the inner circumferential surface of the holder 12 in the radial direction.

When manufacturing the stator 1 described above, first, for example, a plurality of divided cores 21 are arranged in the circumferential direction to form a cylindrical stator core 11. At this time, the divided cores 21 adjacent in the circumferential direction are arranged in a state in which the end faces facing each other in the circumferential direction in the back yoke piece 24 are abutted.
Subsequently, the stator core 11 is press-fitted into the holder 12. At this time, the stator core 11 is press-fitted into the holder 12 while only the outer peripheral surface of the protruding portion 41 of the stator core 11 is in contact with the inner peripheral surface of the holder 12. The stator core 11 is not limited to press-fitting as long as it is configured to be fitted on the holder 12, and may be shrink-fitted or the like. In the above description, the configuration in which the split cores 21 are press-fitted into the holder 12 in a state where the split cores 21 are arranged in a cylindrical shape has been described. However, the configuration is not limited thereto, and the configuration in which the split cores 21 are arranged in a cylindrical shape in the holder 12 is described. It does not matter.

As described above, in the present embodiment, the stator core 11 is fitted to the holder 12 in a state in which both end portions in the circumferential direction of the split core 21 are separated from the inner peripheral surface of the holder 12 in the radial direction.
According to this configuration, the boundary portion between the adjacent divided cores 21 and the press-fitted portion of the holder 12 in the divided core 21 can be separated in the circumferential direction. Thereby, it can suppress that the plate 22 located in the edge part of the axial direction among division | segmentation core 21 generate | occur | produces by the load which acts between division | segmentation core 21 and the holder 12 at the time of press injection etc., and generation | occurrence | production.
In particular, in this embodiment, there is no need to increase the number of caulking locations as in the prior art, so that an increase in iron loss can be suppressed and a reduction in efficiency of the rotating electrical machine can be suppressed.

  In the present embodiment, the protrusion 41 is formed at a portion of the outer peripheral surface of the split core 21 that avoids both ends in the circumferential direction, so that the load acting between the protrusion 41 and the holder 12 can be easily obtained. It becomes easy to ensure, and the split core 21 can be reliably held in the holder 12.

  In the present embodiment, the protruding portion 41 is formed in the back yoke piece 24 at a position overlapping the tooth portion 14 when viewed from the radial direction, and therefore, the boundary portion between the divided cores 21 adjacent in the circumferential direction and the divided core The distance from the press-fitted portion of the holder 12 at 21 can be secured. Therefore, it is possible to reliably suppress the floating and turning of the plate 22.

In the present embodiment, since the protruding portion 41 is formed over the entire axial direction of the split core 21, the entire axial direction of the stator core 11 can be stably held in the holder 12.
Moreover, since the plate 22 of the same shape and size can be used over the whole axial direction in the split core 21, cost reduction can be achieved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 2 is a partial plan view of the stator 200 according to the second embodiment. In the second embodiment, the shape of the protruding portion 241 is different from that of the first embodiment. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
In the stator 200 shown in FIG. 2, the protruding portion 241 of each divided core 221 is formed in a convex arc shape toward the outside in the radial direction in a plan view viewed from the axial direction. Specifically, the curvature radius on the outer peripheral surface of the protrusion 241 is smaller than the curvature radius on the inner peripheral surface of the holder 12.

  Moreover, the both ends of the circumferential direction in the protrusion part 241 are connected with the outer peripheral surface of the division | segmentation core 221 (rib part 32) smoothly. That is, both end portions in the circumferential direction of the protruding portion 241 are connected to the outer peripheral surface of the split core 221 through the curved portion 245 that protrudes inward in the radial direction.

  According to this embodiment, in addition to the same operational effects as the above-described embodiment, the following operational effects are achieved. That is, since the outer peripheral surface of the projecting portion 241 and the inner peripheral surface of the holder 12 are in contact with each other with curved surfaces, the projecting portion 241 is prevented from being caught on the inner peripheral surface of the holder 12 during press-fitting or the like. It is possible to reliably suppress the occurrence of cracks and the like.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 3 is a partial plan view of a stator 300 according to the third embodiment. In the present embodiment, the position of the protruding portion 341 is different from that of the above-described embodiment.
In the stator 300 shown in FIG. 3, the protruding portion 341 of each split core 321 is formed at a position that overlaps the caulking portion 33 in the radial direction among the flange portions 32 in a side view as viewed from the radial direction. In this case, each projecting portion 341 is formed at a position on the outer peripheral surface of the split core 321 that avoids the outer end portion in the circumferential direction of each flange portion 32 and the entire base portion 31. Therefore, the stator core 11 is press-fitted into the holder 12 with both end portions and the center portion in the circumferential direction of each divided core 21 being radially separated from the inner peripheral surface of the holder 12. Note that the circumferential width of the protruding portion 341 is wider than the width of the crimping portion 33.

According to this embodiment, while exhibiting the same operation effect as embodiment mentioned above, there exist the following operation effects. That is, in the split core 321, the protruding portion 341 is disposed at a position close to the crimping portion 33 where the connection strength between the plates 22 adjacent in the axial direction is relatively high. Thereby, it is possible to reliably prevent the plate 22 from being lifted or turned up due to a load or the like acting between the holder 12 and the protruding portion 341 during press-fitting.
Note that the caulking portion 33 is generally formed in a portion of the split core 21 that is less affected by the magnetic circuit. Therefore, by forming the protruding portion 341 at a position overlapping the caulking portion 33 in a side view as viewed from the radial direction, the influence of the magnetic circuit due to the load acting between the holder 12 and the protruding portion 341 is reduced as much as possible. it can.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 4 is a partial plan view of a stator 400 according to the fourth embodiment. In the present embodiment, the positions of the crimping portion 433 and the protruding portion 441 are different from the above-described embodiment.
In the stator 400 shown in FIG. 4, the caulking portion 433 of each divided core 421 is formed on the base portion 31 of the back yoke piece 24.

  A projecting portion 441 is formed at a position overlapping the caulking portion 33 on the outer peripheral surface of the base portion 31 in a side view as viewed from the radial direction. In the example of FIG. 4, the circumferential width of the protruding portion 441 is narrower than the base portion 31 and wider than the caulking portion 433. Therefore, the stator core 11 is press-fitted into the holder 12 in a state in which both end portions in the circumferential direction of the base portion 31 and the flange portion 32 are radially separated from the inner peripheral surface of the holder 12 among the divided cores 421.

  According to the present embodiment, after the caulking portion 433 and the protruding portion 441 are brought close to each other, the boundary portion between the adjacent divided cores 421 and the press-fitting portion of the holder 12 in the divided core 421 can be separated. . Thereby, it can suppress reliably that the float of the plate 22 and turning-up generate | occur | produce.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. FIG. 5 is a partial cross-sectional view of a stator 500 according to the fifth embodiment. FIG. 6 is a partial plan view of a stator 500 according to the fifth embodiment. This embodiment is different from the above-described embodiment in that a protruding portion 541 is formed at the central portion of the split core 521 in the axial direction.
In the stator 500 shown in FIGS. 5 and 6, the projecting portion 541 of each divided core 521 is formed at the central portion in the axial direction. In the side view as seen from the circumferential direction, the protruding portion 541 is formed in a convex arc shape toward the outer side in the radial direction. That is, the protruding amount of the protruding portion 541 toward the outer side in the radial direction gradually increases from the both sides in the axial direction toward the central portion. Further, the protrusion 541 is formed over the entire circumferential direction of the back yoke piece 24 of the split core 521 in a plan view viewed from the axial direction. Note that a plurality of protruding portions 541 may be provided at intervals in the axial direction.

  On the other hand, of the outer peripheral surface of each divided core 521, both end portions in the axial direction are spaced radially from the inner peripheral surface of the holder 12 over the entire circumferential direction. That is, the stator core 11 of the present embodiment is press-fitted into the inner peripheral surface of the holder 12 only at the central portion in the axial direction.

  The protrusions 541 described above are formed by stacking a plurality of plates 22 having different planar shapes when viewed from the axial direction. That is, among the plates 22, the central plate 22 a positioned at the axial center (the portion corresponding to the protruding portion 541) is the end plate 22 b positioned at both axial ends (portions other than the protruding portion 541). In contrast, the outer peripheral surface of the back yoke piece 24 is formed so as to be positioned on the outer side in the radial direction. The shapes of the plates 22a and 22b can be changed as appropriate.

  According to the present embodiment, among the outer peripheral surfaces of the divided cores 521, both end portions in the axial direction are separated from the inner peripheral surface of the holder 12 in the radial direction over the entire circumferential direction. The floating and turning of the plate 22 at the axial end of the core 521 can be reliably suppressed.

The technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In other words, the configuration described in the above-described embodiment is merely an example, and can be changed as appropriate.
For example, in the above-described embodiment, the configuration in which the plates 22 adjacent in the axial direction are connected via the caulking portion has been described. However, the connection method of the plates 22 can be changed as appropriate. For example, the plates 22 may be connected by an adhesive or the like.
Moreover, you may combine each embodiment mentioned above suitably.

  In the above-described embodiment, the configuration in which the protruding portion is formed on one of the base portion 31 and the flange portion 32 of the back yoke piece 24 has been described, but is not limited thereto. The protruding portion may be formed on both the base portion 31 and the flange portion 32, or may be formed so as to straddle between the base portion 31 and the flange portion 32.

Although embodiment mentioned above demonstrated the case where a part of outer peripheral surface of each division | segmentation core formed the protrusion part which protrudes toward the outer side of radial direction, it is not restricted to this. That is, the stator core 11 is fitted in the holder 12 in a state where both end portions in the circumferential direction are radially spaced from the inner circumferential surface of the holder 12 among the outer peripheral surfaces of at least the axial end portions of the split core. It doesn't matter. In the present embodiment, the end in the axial direction of the split core is an area in which several 22 plates including the plate 22 positioned on the outermost side in the axial direction are stacked.
In this case, for example, like the stator 600 shown in FIG. 7, the curvature radius of the entire outer peripheral surface of each divided core 621 may be formed smaller than the curvature radius of the inner peripheral surface of the holder 12. According to this configuration, of the outer peripheral surface of each divided core 621, both end portions in the circumferential direction are separated from the inner peripheral surface of the holder 12, and the stator core 11 is press-fitted into the holder 12 at the central portion in the circumferential direction. Can do.

  In addition, in the range which does not deviate from the meaning of this invention, it is possible to replace suitably the component in the embodiment mentioned above by the known component, and you may combine each modification mentioned above suitably.

1,200,300,400,500,600 ... stator 11 ... stator core 12 ... holder 14 ... tooth portions 21,221,321,421,521,621 ... divided core 22 ... plate 24 ... back yoke piece 33,433 ... caulking Part 41,241,341,441,541,641 ... protrusion

Claims (7)

A split core in which magnetic plates are laminated;
A plurality of the divided cores are arranged, and a stator core formed in a cylindrical shape,
A holder fitted with the stator core,
The stator core is configured such that at least both ends of the divided core in the circumferential direction are spaced apart from the inner circumferential surface of the holder in the radial direction among the outer circumferential surfaces facing the radially outer side at the axial end portion. A stator characterized by being fitted inside.   Of the outer peripheral surface facing the outer side in the radial direction of the split core, a portion that avoids both ends in the circumferential direction protrudes outward in the radial direction and contacts the inner peripheral surface of the holder The stator according to claim 1, wherein the stator is formed. The split core is
A back yoke piece extending in the circumferential direction;
A tooth portion that protrudes inward in the radial direction from a central portion in the circumferential direction of the back yoke piece,
3. The stator according to claim 2, wherein the protruding portion is formed on a portion of the outer peripheral surface of the back yoke piece that overlaps with the tooth portion as viewed from the radial direction. The split core is
A back yoke piece extending in the circumferential direction;
A tooth portion that protrudes inward in the radial direction from a central portion in the circumferential direction of the back yoke piece,
The back yoke piece is formed with a caulking portion that connects the plates adjacent in the axial direction,
4. The stator according to claim 2, wherein the protruding portion is formed at a position overlapping with the caulking portion when viewed from the radial direction on an outer peripheral surface of the back yoke piece. 5. The protrusion is formed in a convex arc shape toward the outside in the radial direction in a plan view as viewed from the axial direction,
The stator according to any one of claims 2 to 4, wherein a radius of curvature of the projecting portion is smaller than a radius of curvature of the inner peripheral surface of the holder.   The said protrusion part is contacting the said internal peripheral surface of the said holder in the said radial direction over the said whole axial direction in the said division | segmentation core, The any one of Claims 2-5 characterized by the above-mentioned. The stator described in 1. A portion of the split core that avoids both axial end portions is formed with a protruding portion that protrudes outward in the radial direction and contacts the inner peripheral surface of the holder,
7. The split core according to claim 1, wherein the entire outer peripheral surface of the split core facing outward in the radial direction is spaced from the inner peripheral surface of the holder at both ends in the axial direction. The stator according to item.

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