JP6962772B2 - Stator core cooling structure and rotary electric machine - Google Patents

Description

The present invention relates to a stator core cooling structure and a rotary electric machine.

Conventionally, a rotary electric machine has been used as a power source for a hybrid vehicle or an electric vehicle. As the rotary electric machine, for example, there is a rotary electric machine disclosed in Patent Document 1. The rotary electric machine of Patent Document 1 has a stator core and a holding body. The holder has an annular cross section. The inner peripheral surface of the holder is fitted to the outer peripheral surface of the stator core. As a result, the holding body holds the stator core.

By the way, it is known that when the rotation speed of a rotary electric machine increases, iron loss increases and the temperature of the stator core rises (see, for example, Patent Document 2 below). Therefore, Patent Document 2 below discloses a configuration including a pipe for supplying cooling oil to the stator core.

Japanese Patent No. 5723443 Japanese Unexamined Patent Publication No. 2008-263753

However, in the configuration of Patent Document 2 described above, it is necessary to provide a separate pipe in order to supply the cooling oil. Therefore, it may lead to an increase in the number of parts.
Further, in the configuration in which the stator core is press-fitted into the holder as in Patent Document 1 described above, it may be difficult to supply cooling oil through a pipe between the stator core and the holder.
Therefore, in the conventional configuration, there is room for improvement in that the stator core is cooled after reducing the number of parts.

Therefore, in view of the above circumstances, it is an object of the present invention to provide a stator core cooling structure and a rotary electric machine capable of cooling the stator core while reducing the number of parts as compared with the prior art. do.

In order to solve the above problems, the cooling structure (cooling structure 51 of the embodiment described later) of the stator core (the stator core 15 of the embodiment described later) according to the invention according to claim 1 includes a tubular stator core and the stator core. It is a cooling structure of a stator core having a tubular holding body (holding body 11 of the embodiment described later) surrounding the stator core, and the outer peripheral surface of the stator core (outer peripheral surface 23 of the embodiment described later) and the holding body. A refrigerant passage (refrigerant passage 53 of the embodiment described later) provided between the inner peripheral surface (inner peripheral surface 21 of the embodiment described later) through which the refrigerant can flow, and at least one of the stator core and the holding body. A refrigerant supply port provided and communicating with the refrigerant passage (refrigerant supply port 55 of the embodiment described later) and a refrigerant discharge port provided at at least one of the stator core and the holding body and communicating with the refrigerant passage (described later). The refrigerant discharge port 57) of the embodiment is provided, and the refrigerant supply port is provided so as to open on one end surface (end surface 39a of the embodiment described later) side in the axial direction of the holder, and the refrigerant discharge port is provided. Is provided as an opening on the other end surface (end surface 39b of the embodiment described later) side of the holding body in the axial direction, is formed on the outer peripheral surface of the stator core, and extends in the first direction on the outer peripheral surface of the stator core. A refrigerant recess (the stator recess 33 of the embodiment described later) and a retainer recess (a retainer recess 33 formed on the inner peripheral surface of the holder and extending in the second direction intersecting the inner peripheral surface of the holder in the first direction). It is characterized in that it has a holding body recess 35) of the embodiment described later, and the refrigerant passage is provided between the stator recess and the holding body recess.

Further, the cooling structure of the stator core according to the second aspect of the present invention is characterized in that the retainer recess is formed in a spiral shape extending in the axial direction of the retainer as it extends in the circumferential direction of the retainer. It is said.
Further, in the cooling structure of the stator core according to the third aspect of the present invention, the refrigerant passage is a first passage spirally formed by the holding body recess between the refrigerant supply port and the refrigerant discharge port. And the second passage formed by the stator recess extending linearly from one end to the other end of the stator core in the axial direction are formed in combination with each other.

Further, the cooling structure of the stator core according to the invention of claim 4 is characterized in that the stator core is press-fitted into the holding body.

Further, in the cooling structure of the stator core according to the invention of claim 5 , the holding body holds the stator core, and the case of the rotary electric machine (rotary electric machine 1 of the embodiment described later) (the embodiment described later). It is characterized in that it is a holder fixed to the case 3) (holder 19 of the embodiment described later).

The rotary electric machine according to the invention according to claim 6 is characterized by having the above-mentioned cooling structure for the stator core.

The cooling structure for the stator core according to claim 1 of the present invention includes a refrigerant passage provided between the outer peripheral surface of the stator core and the inner peripheral surface of the holding body, a refrigerant supply port, and a refrigerant discharge port. As a result, the refrigerant flows between the outer peripheral surface of the stator core and the inner peripheral surface of the holding body by flowing through the refrigerant passage, so that the central portion in the axial direction of the stator core, which is hot in the stator core, is cooled. Becomes possible. Therefore, the cooling structure of the stator core according to claim 1 can cool the stator core after reducing the number of parts as compared with the prior art.

Further, the cooling structure of the stator core has a stator recess extending in the first direction on the outer peripheral surface of the stator core and a holding body recess extending in the second direction intersecting the inner peripheral surface of the holding body in the first direction. , The refrigerant passage is provided between the stator recess and the holder recess. As a result, the refrigerant flows through the refrigerant passage between the stator recess and the holder recess, and thus flows between the outer peripheral surface of the stator core and the inner peripheral surface of the holder along the first and second directions. Therefore, it is possible to efficiently cool the central portion of the stator core in the axial direction. Therefore, the cooling structure of the stator core according to claim 2 can efficiently cool the stator core after reducing the number of parts as compared with the prior art.

In the cooling structure of the stator core according to claim 2 of the present invention, the recesses of the retainer are formed in a spiral shape extending in the axial direction of the retainer as it extends in the circumferential direction of the retainer, so that the refrigerant is the outer periphery of the stator core. It can flow spirally between the surface and the inner peripheral surface of the holder. Therefore, the cooling structure of the stator core according to claim 3 can efficiently cool the stator core after reducing the number of parts as compared with the prior art.

In the cooling structure of the stator core according to claim 4 of the present invention, since the stator core is press-fitted into the holding body, the outer peripheral surface of the stator core and the inner peripheral surface of the holding body are compared with the case where the refrigerant passage is not provided. Since the contact area with and is reduced and the tip of the fitting portion is locally deformed, the compressive stress remaining on the stator core after press fitting is reduced. Therefore, the cooling structure of the stator core according to claim 4 can suppress a decrease in magnetic properties due to compressive stress.

In the cooling structure of the stator core according to claim 5 of the present invention, since the holder is a holder fixed to the case of the rotary electric machine while holding the stator core, the case has a refrigerant passage, a refrigerant supply port, and a refrigerant discharge. It is possible to cool the axially central portion of the stator core without providing an outlet. Therefore, in the cooling structure of the stator core according to claim 5, even if the holding body includes a case, the stator core can be efficiently cooled by using the refrigerant without lowering the strength of the case.

Further, since the rotary electric machine according to claim 6 of the present invention has the above-mentioned cooling structure for the stator core, it is a low-cost and high-performance rotary electric machine capable of cooling the stator core while reducing the number of parts. be able to.

It is sectional drawing which shows the whole structure of the rotary electric machine which comprises the cooling structure of the stator core of embodiment. It is the figure which looked at the cooling structure of the stator core of embodiment from the axial direction. FIG. 2 is a sectional view taken along line III-III of FIG. FIG. 2 is a sectional view taken along line IV-IV of FIG.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

(Embodiment)
The stator 5 of the embodiment will be described.
FIG. 1 is a cross-sectional view showing the overall configuration of a rotary electric machine including the cooling structure of the stator core of the embodiment.
The rotary electric machine 1 of the present embodiment is a traveling motor mounted on a vehicle such as a hybrid vehicle or an electric vehicle. However, the configuration of this embodiment is not limited to the above example, and can be applied to motors for other purposes such as power generation motors mounted on vehicles. Further, the configuration of the present embodiment is a rotary electric machine other than that mounted on a vehicle, and can be applied to all so-called rotary electric machines including a generator.

As shown in FIG. 1, the rotary electric machine 1 according to the embodiment includes a case 3, a stator 5, a rotor 7, and an output shaft 9.
The output shaft 9 is rotatably supported by the case 3.
The rotor 7 has a rotor core 27 and a magnet (not shown) attached to the rotor core 27. The rotor core 27 is formed in a cylindrical shape that is fitted onto the output shaft 9. In the following description, the direction along the axis C of the output shaft 9 may be simply referred to as the axial direction, the direction orthogonal to the axis C may be referred to as the radial direction, and the direction around the axis C may be referred to as the circumferential direction.

The case 3 is formed in a cylindrical shape. The case 3 houses the stator 5 and the rotor 7. The stator 5 is formed in a cylindrical shape arranged coaxially with the case 3. The stator 5 is attached to the inner peripheral surface 13 of the case 3. The stator 5 causes a rotating magnetic field to act on the rotor 7.

The stator 5 includes a stator core 15, a coil 17, and a holder 19.
The stator core 15 is arranged coaxially with the axis C, and is formed in a cylindrical shape that surrounds the rotor 7 from the outside in the radial direction. The stator core 15 is formed by laminating annular plates 43 formed by punching or the like on an electromagnetic steel plate in the axial direction. The stator core 15 may be a so-called dust core.
The coil 17 is mounted on the stator core 15.

The holder 19 is formed in an annular shape. The holder 19 holds the stator core 15. The stator core 15 is press-fitted into the holder 19, and the outer peripheral surface 23 of the stator core 15 is fitted to the inner peripheral surface 21 of the holder 19. As a result, the holder 19 holds the stator core 15. The holder 19 is fixed to the inner peripheral surface 13 of the case 3 by, for example, a bolt (not shown). As a result, the stator 5 is attached to the inner peripheral surface 13 of the case 3.
The holding body 11 of the present embodiment includes the above-mentioned case 3 and the above-mentioned holder 19. The holding body 11 is formed in a cylindrical shape centered on the axis C as a whole, and surrounds and holds the stator core 15.

FIG. 2 is a view of the cooling structure of the stator core of the embodiment as viewed from the axial direction.
As shown in FIG. 2, a plurality of slots 31 are formed in the end surface 29 of the stator core 15. The plurality of slots 31 are arranged at intervals in the circumferential direction of the end face 29. The slot 31 penetrates the stator core 15 in the axial direction.

The coil 17 is housed in the plurality of slots 31. The coil 17 is mounted on the stator core 15 in a state where a part of the coil 17 is housed in the plurality of slots 31. The coil 17 is a three-phase coil composed of a U phase, a V phase, and a W phase. The coils 17 of each phase are insulated from each other via insulating paper. Further, the coil 17 of each phase is insulated from the stator core 15 via an insulating paper.

A plurality of stator recesses 33 are provided on the outer peripheral surface 23 of the stator core 15.
The plurality of stator recesses 33 are formed in a concave shape that is recessed inward in the radial direction, and are arranged side by side in the entire circumferential direction of the outer peripheral surface 23. The stator recess 33 is provided so as to extend linearly along the axial direction of the outer peripheral surface 23 (corresponding to the "first direction" of the claim). The stator recess 33 has a V-shaped cross section when viewed from the axial direction. A first convex portion 41 is formed between the adjacent stator recesses 33 and 33. The first convex portion 41 has, for example, a triangular cross section when viewed from the axial direction.

The inner peripheral surface 21 of the holder 19 is fitted to the outer peripheral surface 23 of the stator core 15. A holding body recess 35 is provided on the inner peripheral surface 21 of the holder 19.
The holding body recess 35 is formed in a concave shape that is recessed outward in the radial direction, and extends in a direction intersecting the stator recess 33 (corresponding to the "second direction" of the claim). More specifically, the holding body recess 35 is formed on the inner peripheral surface 21 of the holder 19 in a spiral shape that extends in the axial direction of the holding body 11 as it extends in the circumferential direction of the holding body 11. The holding body recess 35 is provided over the entire inner peripheral surface 21 of the holder 19. The holding body recess 35 is formed by cutting, for example, the inner peripheral surface of the holder 19 with a lathe or the like. The holding body recess 35 has a U-shaped cross section when viewed from the circumferential direction.

A plurality of mounting pieces 37 are formed on the outer peripheral portion 25 of the holder 19. The plurality of mounting pieces 37 are arranged at intervals in the circumferential direction of the outer peripheral portion 25. The mounting piece 37 is formed so as to project outward in the radial direction from the outer peripheral portion 25 of the holder 19. The holder 19 is attached to the case 3 by fixing a plurality of attachment pieces 37 to the case 3 with bolts (not shown), for example. A refrigerant discharge port 57 is provided inside the mounting piece 37 in the radial direction. The refrigerant discharge port 57 will be described later.

FIG. 3 is a sectional view taken along line III-III of FIG.
FIG. 4 is a sectional view taken along line IV-IV of FIG.
As shown in FIGS. 3 and 4, a second convex portion 45 is formed between the plurality of holding body recesses 35. The second convex portion 45 has a triangular cross section when viewed from the circumferential direction. The tip of the second convex portion 45 and the tip of the first convex portion 41 are in contact with each other by press-fitting the stator core 15 into the holder 19.

Subsequently, the cooling structure 51 of the stator core 15 of the present embodiment will be described with reference to FIGS. 3 and 4. The cooling structure 51 of the stator core 15 of the present embodiment includes a refrigerant passage 53, a refrigerant supply port 55, and a refrigerant discharge port 57.

The refrigerant passage 53 is a passage through which the refrigerant that cools the stator core 15 flows. The refrigerant passage 53 is provided between the outer peripheral surface 23 of the stator core 15 and the inner peripheral surface 21 of the holder 19, and is provided between the stator recess 33 and the holding body recess 35. Further, the refrigerant passage 53 is provided from one end to the other end in the axial direction of the stator core 15 and the holder 19.
In addition, in FIG. 3 and FIG. 4, the refrigerant is shown by dots. As the refrigerant, for example, oil that circulates inside and outside the motor is adopted.

The refrigerant supply port 55 is provided so as to open on one end surface 39a side of the holder 19 and communicates with the refrigerant passage 53. The refrigerant supply port 55 is arranged outside the holding body recess 35 of the refrigerant passage 53 in the radial direction. The refrigerant supply port 55 supplies the refrigerant to the holding body recess 35 from the outside of the stator core 15. A supply pipe (not shown) is connected to the opening of the refrigerant supply port 55.
The refrigerant discharge port 57 is provided so as to open on the other end surface 39b side of the holder 19 and communicates with the refrigerant passage 53. The refrigerant discharge port 57 is arranged outside the holding body recess 35 of the refrigerant passage 53 in the radial direction. The refrigerant discharge port 57 discharges the refrigerant flowing through the holding body recess 35 to the outside of the stator core 15. A discharge pipe (not shown) is connected to the opening of the refrigerant discharge port 57. In addition, the discharge pipe is not connected, and the refrigerant is discharged from the discharge port in a splash, which may be used for cooling other parts.

The supply pipe, the refrigerant supply port 55, the refrigerant passage 53 (stator recess 33 and the holding body recess 35), the refrigerant discharge port 57, and the discharge pipe form a refrigerant circuit. The refrigerant circuit is provided with, for example, a pump (not shown). By driving the pump, the refrigerant in the refrigerant circuit is circulated. The form of the pump is not particularly limited, and may be an electric pump or a mechanical pump.

Subsequently, a method for cooling the stator core 15 will be described.
When the pump is driven, the refrigerant stored in the bottom of the case 3 circulates in the refrigerant circuit. Specifically, when the pump is driven, the refrigerant stored in the bottom of the case 3 flows in the order of the supply pipe, the refrigerant supply port 55, the refrigerant passage 53, the refrigerant discharge port 57, and the discharge pipe, and the case 3 Return to the bottom of the inside.

In the above-mentioned refrigerant circulation, the flow of the refrigerant in the refrigerant supply port 55, the refrigerant passage 53, and the refrigerant discharge port 57 constituting the cooling structure 51 of the stator core 15 will be described.
The refrigerant stored in the bottom of the case 3 is supplied to the supply pipe by a pump. The refrigerant flowing through the supply pipe flows through the refrigerant supply port 55, and a part of the refrigerant flows into the holding body recess 35. The refrigerant that has flowed into the holding body recess 35 flows through the holding body recess 35 toward the refrigerant discharge port 57. As a result, the refrigerant spirally flows between the outer peripheral surface 23 of the stator core 15 and the inner peripheral surface 21 of the holder 19 to cool the stator core 15. The refrigerant flowing through the holding body recess 35 is discharged from the refrigerant discharge port 57 to the discharge pipe.

Further, the refrigerant flowing through the supply pipe flows through the refrigerant supply port 55, and a part of the refrigerant flows into the stator recess 33. The refrigerant that has flowed into the stator recess 33 flows through the stator recess 33 toward the other end. As a result, the refrigerant flows along the axial direction between the outer peripheral surface 23 of the stator core 15 and the inner peripheral surface 21 of the holder 19, and cools the stator core 15. The refrigerant flowing through the stator recess 33 is discharged from the refrigerant discharge port 57 into the discharge pipe.
The refrigerant discharged from the refrigerant discharge port 57 to the discharge pipe is stored in the bottom portion of the case 3. The refrigerant stored in the bottom of the case 3 is supplied to the supply pipe by a pump and circulates in the refrigerant circuit.

In the cooling structure 51 of the stator core 15 of the present embodiment, the refrigerant passage 53 provided between the outer peripheral surface 23 of the stator core 15 and the inner peripheral surface 21 of the holding body 11, the refrigerant supply port 55, and the refrigerant discharge port 57 Equipped with. As a result, the refrigerant flows between the outer peripheral surface 23 of the stator core 15 and the inner peripheral surface 21 of the holding body 11 by flowing through the refrigerant passage 53, so that the temperature in the stator core 15 is high in the axial direction of the stator core 15. It becomes possible to cool the central part of. Therefore, the cooling structure 51 of the stator core 15 of the present embodiment can cool the stator core 15 after reducing the number of parts as compared with the prior art.

In the cooling structure 51 of the stator core 15 of the present embodiment, the stator recess 33 extending axially on the outer peripheral surface 23 of the stator core 15 and the holding body recess extending axially intersecting the inner peripheral surface 21 of the holding body 11 The refrigerant passage 53 is provided between the stator recess 33 and the retainer recess 35. As a result, the refrigerant flows through the refrigerant passage 53 between the stator recess 33 and the holding body recess 35, so that the refrigerant flows in the axial direction and the axial direction between the outer peripheral surface 23 of the stator core 15 and the inner peripheral surface 21 of the holding body 11. Since it can be distributed along the direction intersecting with the above, it is possible to efficiently cool the central portion of the stator core 15 in the axial direction. Therefore, the cooling structure 51 of the stator core 15 of the present embodiment can efficiently cool the stator core 15 after reducing the number of parts as compared with the prior art.

In the cooling structure 51 of the stator core 15 of the present embodiment, the holding body recess 35 is formed in a spiral shape extending in the axial direction of the holding body 11 as it extends in the circumferential direction of the holding body 11, so that the refrigerant is the refrigerant of the stator core 15. It can flow spirally between the outer peripheral surface 23 and the inner peripheral surface 21 of the holding body 11. Therefore, the cooling structure 51 of the stator core 15 of the present embodiment can efficiently cool the stator core 15 after reducing the number of parts as compared with the prior art.

In the cooling structure 51 of the stator core 15 of the present embodiment, since the stator core 15 is press-fitted into the holding body 11, the outer peripheral surface 23 of the stator core 15 and the holding body 11 are compared with the case where the refrigerant passage 53 is not provided. Since the contact area with the inner peripheral surface 21 is reduced and the tip of the fitting portion is locally deformed, the compressive stress remaining on the stator core 15 after press fitting is reduced. Therefore, the cooling structure 51 of the stator core 15 of the present embodiment can suppress the deterioration of the magnetic characteristics due to the compressive stress.

In the cooling structure 51 of the stator core 15 of the present embodiment, the holding body 11 is a holder 19 fixed to the case 3 of the rotary electric machine 1 while holding the stator core 15, so that the refrigerant passage 53 and the refrigerant are supplied to the case 3. It is possible to cool the axially central portion of the stator core 15 without providing the port 55 and the refrigerant discharge port 57. Therefore, the cooling structure 51 of the stator core 15 of the present embodiment can efficiently cool the stator core 15 by using the refrigerant without lowering the strength of the case 3 even if the holding body 11 includes the case 3. ..

Further, since the rotary electric machine 1 of the present embodiment includes the cooling structure 51 of the stator core 15 described above, the rotary electric machine 1 is a low-cost and high-performance rotary electric machine that can cool the stator core 15 after reducing the number of parts. be able to.

The present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications can be considered within the technical scope thereof.

For example, in the above-described embodiment, the stator core 15 is press-fitted into the holding body 11, but the stator core 15 may be shrink-fitted into the holding body 11. In this case, the contact area between the outer peripheral surface 23 of the stator core 15 and the inner peripheral surface 21 of the holding body 11 becomes smaller than in the case where the refrigerant passage 53 is not provided, and the tip of the fitting portion is locally deformed. Therefore, the compressive stress remaining on the stator core 15 after shrink fitting is reduced. Therefore, the cooling structure 51 of the stator core 15 can suppress the deterioration of the magnetic characteristics due to the compressive stress of the stator core 15 even when the stator core 15 is shrink-fitted into the holding body 11, and the rotary electric machine 1 It is possible to suppress the deterioration of the performance of. Other functions and effects are the same as those of the above-described embodiment in which the stator core 15 is press-fitted into the holding body 11, and thus the description thereof will be omitted.

In the above-described embodiment, the outer peripheral surface 23 of the stator core 15 is provided with a stator recess 33 extending along the axial direction, and the inner peripheral surface 21 of the holder 19 is provided with a holding body recess 35 extending along the direction intersecting the axial direction. .. On the other hand, the outer peripheral surface 23 of the stator core 15 may be provided with a stator recess extending along the direction intersecting the axial direction, and the inner peripheral surface 21 of the holder 19 may be provided with a holding body recess extending along the axial direction.

Further, in the above-described embodiment, the refrigerant supply port 55 and the refrigerant discharge port 57 are provided on both end faces 39a and 39b in the axial direction of the holder 19, respectively, but the refrigerant supply port 55 is provided on one of the same end faces 39a (39b). And the refrigerant discharge port 57 may be provided.

Further, in the above-described embodiment, the refrigerant passage 53 includes the stator recess 33 and the holding body recess 35, but it is not always necessary to provide both the stator recess 33 and the holding body recess 35, and the stator recess 33 or the holding body recess 35. Any one of 35 may be provided. Further, in the above-described embodiment, the holding body recess 35 is spirally formed, but in addition, for example, it may be linearly formed along the axial direction or the circumferential direction.

In addition, it is possible to replace the components in the above-described embodiment with well-known components as appropriate without departing from the spirit of the present invention.

1 Rotating electric machine 3 Case 11 Holder 15 Stator core 19 Holder 21 (Holder) Inner peripheral surface 23 (Stator core) Outer surface 33 Stator recess 35 Holder recess 51 Cooling structure 53 Refrigerant passage 55 Refrigerant supply port 57 Refrigerant discharge port

Claims (6)

Cylindrical stator core and
A cooling structure for a stator core having a cylindrical holding body surrounding the stator core.
A refrigerant passage provided between the outer peripheral surface of the stator core and the inner peripheral surface of the holding body and through which the refrigerant can flow,
A refrigerant supply port provided on at least one of the stator core and the holding body and communicating with the refrigerant passage, and a refrigerant supply port.
A refrigerant discharge port provided on at least one of the stator core and the holding body and communicating with the refrigerant passage, and a refrigerant discharge port.
With
The refrigerant supply port is provided so as to open on one end surface side in the axial direction of the holder.
The refrigerant discharge port is provided so as to open on the other end surface side in the axial direction of the holder .
A stator recess formed on the outer peripheral surface of the stator core and extending in the first direction on the outer peripheral surface of the stator core.
It has a holding body recess formed on the inner peripheral surface of the holding body and extending in the second direction intersecting the inner peripheral surface of the holding body in the first direction.
A cooling structure for a stator core, wherein the refrigerant passage is provided between the stator recess and the holder recess. The holder recess, the cooling structure of the stator core according to claim 1, characterized in that it is formed in a spiral shape extending in the axial direction of the holding member in accordance with extending in the circumferential direction of the holding member. The refrigerant passage is between the refrigerant supply port and the refrigerant discharge port.
The first passage formed spirally by the retainer recess and
A second passage formed by the stator recess extending linearly from one end to the other end of the stator core in the axial direction.
The cooling structure for the stator core according to claim 2 , wherein the stator cores are formed in combination with each other. The stator core cooling structure of the stator core as claimed in any one of claims 3, characterized in that it is press-fitted into the holder. The cooling structure for a stator core according to claim 4 , wherein the holding body is a holder fixed to a case of a rotary electric machine while holding the stator core. A rotary electric machine comprising the stator core cooling structure according to any one of claims 1 to 5.

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