Stator for rotary electric machine and method of manufacturing stator for rotary electric machine

Abstract

To provide a stator for a rotary electric machine that can prevent leakage of cooling oil from a slot of a stator core to a rotor with an inexpensive arrangement.SOLUTION: A stator 2 for a rotary electric machine comprises: a stator core 20 that has an inner peripheral surface 20a centered at an axis and has a plurality of circumferential slots 22 extending in a radial direction; a coil 21 that is arranged on the slot 22; and a sheet-shaped external insulation member 50 constructed in an approximately cylindrical shape centered at the axis so as to face the inner peripheral surface 20a. The external insulation member 50 integrally includes a foam body 52 extending into the inside of the stator core 20. The stator core 20 further includes: a cooling medium supply part that guides a cooling oil to the slot 22; and an opening 221 provided in the inner peripheral surface 20a such that the foam body 52 extends into the slot 22.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a stator for a rotating electric machine and a method for manufacturing a stator for a rotating electric machine. [Background technology]

[0002] Conventionally, there has been known a stator configured such that a blocking member is engaged in the axial direction with a slot provided on the inner peripheral surface of a stator core to block the opening of the slot and cooling oil is allowed to circulate through the inside of the slot (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-271150 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a configuration in which a blocking member is engaged with the opening of a slot, as in the stator described in Patent Document 1, the slot and the blocking member need to be formed with high precision relative to each other, which increases costs. [Means for solving the problem]

[0005] A stator for a rotating electric machine according to one aspect of the present invention includes a stator core having a circumferential surface centered on an axis and having a plurality of circumferential slots extending radially, a coil arranged in the slots, and a sheet-like or film-like insulating member configured in a substantially cylindrical shape centered on the axis so as to face the circumferential surface. The insulating member has a foam integrally therewith that penetrates into the inside of the stator core, and the stator core further has a cooling medium supply section that introduces a cooling medium to the slots, and a foam introduction section that is provided on the circumferential surface so that the foam penetrates into the inside of the stator core.

[0006] Another aspect of the present invention is a manufacturing method for a stator for a rotating electric machine having a stator core having a circumferential surface centered on the axis and having a plurality of circumferential slots extending radially, and coils arranged in the slots, wherein a cooling medium flows through the slots, the method including an arrangement step of arranging a sheet-like or film-like insulating member having a foam layer on the surface facing the slot and configured in an approximately cylindrical shape centered on the axis, so as to face the circumferential surface, an abutment step of abutting the insulating member to the circumferential surface, and a heating step of heating the insulating member abutting the circumferential surface. Effect of the Invention

[0007] According to the present invention, leakage of the cooling medium from the slots to the rotor can be prevented with an inexpensive configuration. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a configuration of a main part of a rotating electric machine including a stator for a rotating electric machine according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an enlarged view of a main part of FIG. 1 showing the configuration of a slot. [Diagram 3] 13 is a perspective view of an inner insulating member disposed in the slot; FIG. [Figure 4] 4 is a perspective view illustrating a manufacturing process of the stator for a rotating electric machine according to the embodiment of the present invention; FIG. [Diagram 5] 5 is a diagram showing a configuration of an insulating member included in the stator for a rotating electric machine shown in FIG. 4. [Figure 6] 5A to 5C are diagrams illustrating a method for manufacturing a stator for a rotating electric machine according to an embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 4 is a diagram illustrating the flow of cooling oil into a slot. [Figure 9] 11A and 11B are diagrams illustrating modified examples of an insulating member used in a stator for a rotating electric machine according to an embodiment of the present invention. [Figure 10] FIG. 13 is a diagram showing a modified example of the stator for a rotating electric machine according to the embodiment of the present invention. [Figure 11A]11 is a cross-sectional view taken along line AA in FIG. 10. [Figure 11B] FIG. 11 is a cross-sectional view taken along line BB in FIG. [Figure 12] FIG. 3 is a diagram showing a modification of FIG. 2. [Figure 13] FIG. 2 is a diagram showing an example in which the stator for a rotating electric machine according to the embodiment of the present invention is configured as an inner stator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 13. Fig. 1 is a cross-sectional view showing a configuration of a main part of a rotating electric machine 100 including a stator for a rotating electric machine according to an embodiment of the present invention. The rotating electric machine 100 is mounted on a hybrid vehicle or an electric vehicle and can be used as an electric motor for driving the vehicle, and can also be used as a generator. The rotating electric machine 100 can also be mounted on something other than a vehicle and used for various purposes.

[0010] Fig. 1 is a cross-sectional view of a rotating electric machine 100 perpendicular to an axis line CL0. As shown in Fig. 1, the rotating electric machine 100 includes a rotor 1 that rotates about an axis line CL0, and a stator 2 that is provided outside the rotor 1 so as to surround an outer circumferential surface 1a of the rotor 1. A case 3 is disposed around the stator 2. In the following, the direction in which the axis line CL0 extends is defined as the axial direction, the direction extending radially from the axis line CL0 as the radial direction, and the direction along the circumference of a circle centered on the axis line CL0 as the circumferential direction.

[0011] The rotating electric machine 100 is configured as, for example, an embedded magnet type synchronous motor. Thus, the rotor 1 has a rotor core 10 having a substantially annular shape centered on an axis CL0, and a plurality of magnetic pole portions (not shown) formed in the rotor core 10 in the circumferential direction. Note that permanent magnets are embedded in the magnetic pole portions. For example, a rotor shaft (not shown) constituting the output shaft of the rotating electric machine 100 is fitted into an inner peripheral surface 10a of the rotor core 10, and the rotor 1 rotates integrally with the rotor shaft. An outer peripheral surface 1a of the rotor 1 corresponds to the outer peripheral surface of the rotor core 10. The rotor core 10 is formed by stacking a plurality of magnetic steel sheets made of metal, which is a magnetic body, in the axial direction.

[0012] The stator 2 has a substantially annular stator core 20 centered on an axis CL0 having an inner circumferential surface 20a arranged at a predetermined distance in the radial direction from the outer circumferential surface 1a of the rotor 1, a coil 21 attached to the stator core 20, and a substantially cylindrical insulating member 50 interposed between the outer circumferential surface 1a of the rotor 1 and the inner circumferential surface 20a of the stator core 20. The stator core 20 is formed by stacking a plurality of magnetic metal electromagnetic steel plates in the axial direction.

[0013] A plurality of circumferential teeth 23 are provided on the inner peripheral surface 20a of the stator core 20 so as to protrude radially inward. A plurality of circumferential slots 22 are provided between adjacent teeth 23 so as to extend radially outward from the inner peripheral surface 20a, and a coil 21 is disposed in each slot 22. The coil 21 is a conductor having a substantially rectangular cross section. However, the coil 21 may be a conductor having a circular cross section. The outer peripheral surface 20b of the stator core 20 is fitted liquid-tightly into the inner peripheral surface 31 of the case 3.

[0014] The coil 21 is composed of three-phase coils, namely, a U-phase coil, a V-phase coil, and a W-phase coil. The U-phase coil, the V-phase coil, and the W-phase coil are electrically connected to a power conversion device (not shown) or the like via a U-phase lead wire, a V-phase lead wire, and a W-phase lead wire, respectively. When the rotating electric machine is used as an electric motor, three-phase AC power is supplied from the power conversion device to each of the three-phase coils. This generates a magnetic field in the stator 2, and the rotor 1 rotates due to the interaction between this magnetic field and the magnetic field generated by the permanent magnets of the magnetic poles of the rotor 1. As a result, a driving force is generated and the vehicle runs. When the rotating electric machine is used as a generator, the three-phase AC power generated by driving the rotating electric machine is supplied to a power conversion device (not shown) or the like.

[0015] FIG. 2 is an enlarged view of a main part of FIG. 1 showing the configuration inside the slot. As shown in FIG. 2, the slot 22 has an opening 221 provided on the inner peripheral surface 20a of the stator core 20 and an accommodating portion 222 provided on the radially outer side of the opening 221. The accommodating portion 222 has a pair of side surfaces 222a, 222b facing each other and a bottom surface 222c on the radially outer side connecting the pair of side surfaces 222a, 222b. The width of the accommodating portion 222, i.e., the distance (circumferential length) between the pair of side surfaces 222a, 222b, is constant over the radially outer side, and the accommodating portion 222 is formed in a substantially rectangular shape elongated in the radial direction. The tooth 23 has protruding portions 231 protruding on both circumferential sides at the tip portion on the radially inner side, and the opening 221 is provided between the pair of protruding portions 231. The width of the accommodating portion 222 is larger than the width of the opening 221.

[0016] In the slot 22, four conductor segments 211 forming the coil 21 are arranged side by side in the radial direction. The number of conductor segments 211 in the slot may be more or less than four. Hereinafter, the four coils 21 (segments 211) in the slot may be referred to as first stage coil 21a, second stage coil 21b, third stage coil 21c, and fourth stage coil 21d in order from the inner diameter side.

[0017] An insulating member (for convenience, referred to as an internal insulating member) 40 is disposed in the slot 22. FIG. 3 is a perspective view showing an overall configuration of the internal insulating member 40. The X direction in FIG. 3 corresponds to the axial direction. As shown in FIG. 3, the internal insulating member 40 has a pair of side walls 41, 42 extending substantially parallel to each other in the axial direction, and a peripheral wall 43 connecting the ends of the pair of side walls 41, 42. When viewed from the axial direction, the internal insulating member 40 has a substantially U-shape as a whole, and a substantially box-shaped storage space SP1 is formed inside the internal insulating member 40. A substantially rectangular opening 44 penetrating the peripheral wall 43 is provided at the axial center of the peripheral wall 43. Substantially rectangular openings 45, 46 are provided at both axial ends of the internal insulating member 40.

[0018] 2, a pair of side walls 41, 42 of the internal insulating member 40 face a pair of side surfaces 222a, 222b of the slot 22, respectively, and the peripheral wall 43 faces a bottom surface 222c of the slot 22. Inner diameter side ends of the pair of side walls 41, 42 abut against outer diameter side end faces of the protruding portions 231 of the teeth 23 and are located on the inner diameter side of the inner circumferential surface of the first stage coil 21a.

[0019] The internal insulating member 40 is formed by folding a sheet or film made of an electrically insulating resin into a substantially U-shape. The axial length of the internal insulating member 40 is the same as the axial length of the stator core 20, and the internal insulating member 40 is disposed inside the stator core 20 without protruding from the axial end face of the stator core 20. The axial length of the internal insulating member 40 may be longer or shorter than the axial length of the stator core 20. The coil 21 is disposed in the housing space SP1 inside the internal insulating member 40. As a result, the internal insulating member 40 is interposed between the coil 21 and the stator core 20, and the coil 21 and the stator core 20 are electrically insulated from each other.

[0020] The coil 21 extends in the axial direction within the accommodation space beyond one axial end face and the other axial end face of the stator core 20. The coil 21 is fixed by a fixing means (not shown), thereby defining the position of the coil 21 in the accommodation space SP1. The fixing means may be a means for fixing the coil end protruding from the axial end face of the stator core 20 by insulating the coil end, or may be a means for providing a portion (a protruding portion protruding in the circumferential direction) that regulates the position of the coil 21 within the slot.

[0021] The area of ​​the storage space SP1 inside the internal insulating member 40 is larger than the area of ​​all the coils (four coils), and a gap 25 is provided between the internal insulating member 40 and each coil 21. Note that, although the entire circumference of each coil 21 is separated from the internal insulating member 40 in Fig. 2, a part of the coil 21 may be in contact with the internal insulating member 40. Coils 21 adjacent to each other in the radial direction may be in contact with each other.

[0022] An insulating member (for convenience, referred to as an external insulating member) 50 is disposed radially inside the stator core 20 over the entire circumference of the inner peripheral surface 20a. The external insulating member 50 is formed by bending a sheet-like member of a predetermined thickness, made of an electrically insulating resin, into a substantially cylindrical shape. As an example, the external insulating member 50 may be made of polyethylene naphthalate. The external insulating member 50 extends in the axial direction from one axial end face to the other axial end face of the stator core 20, and the entire inner peripheral surface 20a of the stator core 20 is covered by the external insulating member 50.

[0023] A foam layer 51 (FIG. 5) having a predetermined thickness is formed in advance over the entire surface of one surface of the external insulating member 50, that is, the surface (outer peripheral surface 50a in FIG. 2) that is the radially outer surface when the external insulating member 50 is curved into a substantially cylindrical shape. The foam layer 51 is made of a thermosetting foamable resin material such as an epoxy-based foamable resin material. The foam layer 51 may be made of a thermoplastic resin material. The foam layer 51 foams and expands when heated to a predetermined temperature, and becomes a foam 52. Note that no foam layer is present on the other surface (inner peripheral surface 50b in FIG. 2) of the external insulating member. For convenience, in the following, after the foam layer 51 becomes the foam 52, the foam 52 is treated as a separate member from the external insulating member 50. However, the foam 52 may be treated as a part of the external insulating member 50, and the external insulating member 50 may have the foam 52.

[0024] In this embodiment, the foam layer 51 is heated in a state in contact with the inner circumferential surface 20a of the stator core 20, as described below. Therefore, the foam 52 is filled into the inside of the slots 22 through the openings 221. As a result, the foam 52 is caught on the protruding portions 231 of the teeth 23, and the external insulating member 50 is held inside the stator core 20 via the foam 52, and the external insulating member 50 is fixed. At this time, the radially outer end of the foam 52 is located radially inward of the inner circumferential surface of the first-stage coil 21a, and a gap is present between the first-stage coil 21a and the foam 52.

[0025] In FIG. 2, the outer peripheral surface 50a of the external insulating member 50 is separated from the inner peripheral surface 20a of the stator core 20, and the foam 52 is interposed between the outer peripheral surface 50a and the inner peripheral surface 20a over the entire circumference, but the configuration of the foam 52 is not limited thereto. For example, the foam layer 51 may be pressed against the inner peripheral surface 20a of the stator core 20 to bring the outer peripheral surface 50a of the external insulating member 50 into contact with the inner peripheral surface 20a of the stator core 20. Therefore, the foam 52 may be provided intermittently in the circumferential direction. That is, the distance Δd from the outer peripheral surface 50a to the inner peripheral surface 20a may be 0 or may be longer than 0. The distance Δd can be changed by adjusting the thickness of the foam layer 51 and the amount or force of pressing the external insulating member 50 radially outward.

[0026] Fig. 4 is a perspective view for explaining a process of attaching the internal insulating member 40 and the external insulating member 50 to the stator core 20. In this case, as shown in Fig. 4, first, the internal insulating member 40 is inserted into the slots 22 along the axial direction (the direction of the arrow A in Fig. 4) of the stator core 20 from one axial direction of the stator core 20. After the internal insulating members 40 are inserted into all of the slots 22, the external insulating member 50 on which the foam layer 51 has been formed in advance is disposed inside the inner circumferential surface 20a of the stator core 20 (disposing process).

[0027] In this arrangement step, the foam layer 51 is positioned radially outward and the external insulating member 50 is curved into a substantially cylindrical shape in the direction of arrow B so that the ends 501, 502 of the external insulating member 50 abut or overlap with each other, as shown in Fig. 5. Then, this external insulating member 50 is accommodated inside the stator core 20 from one axial direction of the stator core 20, as shown in Fig. 4. Note that, although both ends 501, 502 of the external insulating member 50 are abutted against each other in Fig. 4, the both ends 501, 502 may be overlapped.

[0028] After the external insulating member 50 is accommodated inside the stator core 20, the external insulating member 50 is pushed radially outward until it abuts against the inner circumferential surface 20a of the stator core 20, and is then heated (abutment process, heating process). FIG. 6 is a diagram illustrating this process. As shown in FIG. 6, in this case, first, an expansion jig 300 is placed inside the external insulating member 50. The expansion jig 300 has a plurality of pressing blocks 310 (e.g., four) in the circumferential direction, and an axis member 320 that is axially movable along the axis line CL0.

[0029] The pressing blocks 310 are connected to each other, for example, via springs, so that they can move radially about the axis line CL0, that is, can expand and contract. The pressing blocks 310 have a peripheral wall 311 having a substantially arc-shaped outer peripheral surface 311a and inner peripheral surface 311b, and side walls 312, 313 protruding from axial ends of the peripheral wall 311 toward the axis line CL0. The curvature of the outer peripheral surface 311a of the peripheral wall 311 is the same as the curvature of the inner peripheral surface 50b of the external insulating member 50.

[0030] The end portions of the side walls 312, 313 of the pressing block 310 on the axis CL0 side are provided with inclined surfaces 312a, 313a inclined at a predetermined angle with respect to the axis CL0. The shaft member 320 has an inclined surface 321a at its axial tip. The inclination angle of the inclined surface 321a is the same as the inclination angles of the inclined surfaces 312a, 313a. The shaft member 320 can advance and retreat along the axis CL0 inside the pressing block 310 by an actuator (not shown). A heating unit 330 is provided on an inner peripheral surface 311b of the peripheral wall 311 of the pressing block 3100, and the peripheral wall 311 is heated by the operation of the heating unit 330. The heating unit 330 is constituted by, for example, a high-frequency induction heating device.

[0031] When the external insulating member 50 is attached to the inside of the stator core 20, the shaft member 320 is moved in the direction of the arrow B along the axis CL0. That is, the shaft member 320 is advanced into the pressing block 310. When the amount of movement (advancement amount) of the shaft member 320 reaches a predetermined value, the inclined surface 321a of the shaft member 320 abuts against the inclined surfaces 312a, 313a of the pressing block 310, and when the shaft member 320 further moves in the direction of the arrow B from this state, the multiple pressing blocks 310 are simultaneously pressed radially outward (in the direction of the arrow C). After that, when the amount of movement of the shaft member 320 reaches a predetermined value, the outer peripheral surface 311a of the pressing block 310 abuts against the inner peripheral surface 50b of the external insulating member 50. When the shaft member 320 further moves in the direction of the arrow B, the outer diameter of the external insulating member 50 is expanded, and the foam layer 51 comes into close contact with the inner peripheral surface 20a of the stator core 20 (abutting process). In FIG. 6, before the external insulating member 50 is pressed by the pressing block 310, the foam layer 51 is positioned away from the inner surface 20a of the stator core 20, but the foam layer 51 may be positioned in contact with the inner surface 20a.

[0032] Next, the heating unit 330 is operated (heating step). As a result, the temperature of the peripheral wall 311 of the pressing block 310 rises, and the temperature of the external insulating member 50 also rises due to heat transfer from the peripheral wall 311 to the external insulating member 50. Furthermore, the temperature of the foam layer 51 rises with the rise in temperature of the external insulating member 50, and the foam layer 51 starts foaming. At this time, the pressing block 310 restricts the movement of the external insulating member 50 inward in the radial direction, so that the foam layer 51 expands outward in the radial direction. As a result, as shown in FIG. 2, the foam 52 enters the slot through the opening 221, and a part of the accommodation space SP1 in the slot is filled with the foam 52. Note that the peripheral wall 311 may be heated by the heating unit 330 while the external insulating member 50 is pressed outward in the radial direction by the pressing block 310. This makes it possible to shorten the distance Δd (FIG. 2) from the outer circumferential surface 50a of the external insulating member 50 to the inner circumferential surface 20a of the stator core 20.

[0033] When foaming of the foam layer 51 is completed, the shaft member 320 is moved in the opposite direction of the arrow B and is withdrawn from the inside of the pressing block 310. When the shaft member 320 is withdrawn, the pressing block 310 is contracted radially inward by the biasing force of the spring. Then, the expansion jig 300 is removed axially outward. As a result, the external insulating member 50 is held inside the stator core 20 via the foam 52, and the external insulating member 50 is fixed. This completes the manufacture of the stator 2.

[0034] Cooling oil is introduced from the outside of the stator 2 into the storage space SP1 inside the internal insulating member 40, and the flow of the cooling oil cools the coils 21. This point will be described below. As shown in Fig. 4, a groove 200 of a predetermined depth is provided in the outer peripheral surface 20b of the stator core 20 in the axial center of the stator core 20 all around.

[0035] As shown in Fig. 1, the outer peripheral surface 20b of the stator core 20 is liquid-tightly covered by the inner peripheral surface 31 of the case 3. As a result, an annular flow path PA0 centered on the axis line CL0 is formed between the groove 200 (dotted line in Fig. 1) and the inner peripheral surface 31 of the case 3. A flange portion 32 for supplying cooling oil is provided on the outer peripheral surface of the case 3. The flange portion 32 is provided, for example, at the uppermost part in the gravity direction of the outer peripheral surface of the case 3. A through hole 32a is formed in the flange portion 32, penetrating the case 3 in the radial direction, and the external space of the case 3 communicates with the flow path PA0 via the through hole 32a.

[0036] Fig. 7 is a cross-sectional view of the stator core alone taken along line VII-VII in Fig. 4. Note that Fig. 7 shows only a portion of the stator core 20 in the circumferential direction. As shown in Fig. 7, a plurality of through holes 210 are drilled in the bottom surface of the groove 200 of the stator core 20 in the circumferential direction toward the slots 22 so as to radially penetrate the stator core 20. This allows cooling oil to be guided from the outside of the case 3 to the inside of the slots 22 via the through holes 32a of the case 3, the flow passage PA0, and the through holes 210 of the stator core 20.

[0037] 8 is an enlarged cross-sectional view of a main part of the rotating electric machine 100 perpendicular to the axis CL0 along the center line of the through hole 32a of the case 3 in FIG. 1, and shows one slot of the stator core 20. As shown by the arrow in FIG. 8, the cooling oil supplied from the outside of the case 3 flows into a flow path PA0 provided on the outer circumferential surface of the stator core 20 through the through hole 32a of the case 3. The cooling oil that has flowed into the flow path PA0 flows in the circumferential direction along the flow path PA0, and flows into the accommodation space SP1 inside the internal insulating member 40 through the multiple circumferential through holes 210 of the stator core 20 and the opening 44 of the internal insulating member 40.

[0038] The openings 221 of the slots 22 are closed by the foam 52. Therefore, the cooling oil that flows into the storage space SP1 flows in the axial direction through the gaps between the internal insulating member 40 and the coil 21 and the gaps between adjacent coils 21 without passing through the openings 221. Then, the cooling oil flows out of the storage space SP1 through the openings 45, 46 (FIG. 3) at both axial ends of the internal insulating member 40. This allows the cooling oil to flow along the coil 21, thereby enabling the coil 21 to be cooled efficiently.

[0039] In the above, a single sheet-like external insulating member 50 is curved into a substantially cylindrical shape and arranged inside the stator core 20 (FIG. 5), but a plurality of insulating members (referred to as divided insulating members) may be arranged side by side in the circumferential direction. FIG. 9 is a front view of a stator 2 showing an example. As shown in FIG. 9, a plurality of divided insulating members 50A curved in an arc shape are arranged in the circumferential direction inside the inner circumferential surface 20a of the stator core 20.

[0040] At both circumferential ends of the multiple divided insulating members 50A, bent portions 53 are formed by bending radially outward, and the bent portions 53 are inserted into the slots 22 through the openings 221. More specifically, if the interval between adjacent slots 22 in the circumferential direction is defined as one pitch, the divided insulating members 50A extend for two pitches in the circumferential direction, and the bent portions 53 are inserted into a pair of slots 22 that are two pitches apart. At this time, the bent portions 53 of the divided insulating members 50A adjacent in the circumferential direction are inserted into the same slot 22 while abutting against each other. As a result, the divided insulating members 50A are arranged without gaps around the entire circumference inside the stator core 20, and the external insulating member 50 is configured. Note that the divided insulating members 50A may extend in the circumferential direction for one pitch of the slots 22, or may extend for three or more pitches.

[0041] By dividing the external insulating member 50 in the circumferential direction in this manner, the divided insulating member 50A can be arranged facing the inner circumferential surface 20a of the stator core 20 without any gaps in the circumferential direction. This makes it possible to prevent the cooling oil in the slot from leaking radially inward of the external insulating member 50. That is, for example, if there is a gap between the ends 501 and 502 of the external insulating member 50 in FIG. 4, the cooling oil may leak radially inward from the gap. In this regard, by dividing the external insulating member 50 as shown in FIG. 8, it is possible to arrange the divided insulating member 50A in the circumferential direction without any gaps, thereby making it possible to prevent the cooling oil from leaking radially inward of the external insulating member 50. In addition, by inserting the bent portion 53 of the divided insulating member 50A into the slot 22 through the opening 221, the external insulating member 50 (divided insulating member 50A) can be firmly fixed to the stator core 20 via the foam 52.

[0042] According to this embodiment, the following advantageous effects can be obtained. (1) A stator 2 for a rotating electric machine includes a stator core 20 having an inner circumferential surface 20a centered on an axis CL0 and having a plurality of circumferential slots 22 extending in the radial direction, a coil 21 arranged in the slot 22, and a sheet-like external insulating member 50 having a substantially cylindrical shape centered on the axis CL0 so as to face the inner circumferential surface 20a (FIG. 1). The external insulating member 50 integrally includes a foam 52 made of a foam layer 51 formed on one surface, that is, the foam 52 that enters the slot 22 (FIG. 4). The stator core 20 has a groove 200 and a through hole 210 as a cooling oil supply section that guides cooling oil to the slot 22 (FIG. 7). The stator core 20 further has an opening 221 provided on the inner circumferential surface 20a so that the foam 52 enters the slot 22 (FIG. 2).

[0043] This allows the external insulating member 50 to be fixed to the stator core 20 via the foam 52, facing the inner circumferential surface 20a of the stator core 20, with an inexpensive configuration. This prevents the cooling oil flowing through the slots 22 from leaking radially inward through the openings 221 of the slots 22. The external insulating member 50 is a sheet-like member having a foam layer 51 on its surface, and its size and shape can be easily changed. This allows the openings 221 of the stator core 20 of various dimensions to be sealed easily and inexpensively. In addition, since there is no need to insert a separate sealing member into the slots, it is possible to prevent the slots 22 and the coils 21 from being damaged by the sealing member coming into contact with the slots 22 and the coils 21. Furthermore, a heat insulating effect is obtained by the foam 52, and it is possible to suppress the magnet temperature of the rotor 1 from increasing due to heat from the coils 21.

[0044] (2) The external insulating member 50 can be composed of a plurality of circumferentially separated divided insulating members 50A (FIG. 9). The divided insulating members 50A have bent portions 53 bent radially from their circumferential ends so as to be inserted into the slots 22 through the openings 221 (FIG. 9). This makes it possible to firmly hold the external insulating member 50 (divided insulating members 50A) inside the stator core 20. In addition, since the divided insulating members 50A can be arranged without gaps in the circumferential direction, it is possible to reliably prevent leakage of cooling oil inside the slots.

[0045] (3) Stator core 20 is configured so that the circumferential width of openings 221 provided in inner circumferential surface 20a is smaller than the circumferential width of slots 22 ( FIG. 2 ). As a result, foam 52 engages with stator core 20 in an uneven manner through openings 221, and external insulating member 50 can be effectively prevented from falling off stator core 20.

[0046] (4) This embodiment also includes a method for manufacturing a stator 2 for a rotating electric machine, the stator 2 having an inner circumferential surface 20a centered on the axis CL0 and having a plurality of circumferential slots 22 extending in the radial direction, and a coil 21 arranged in the slots 22, and configured so that cooling oil flows through the slots 22. This manufacturing method includes an arrangement step of arranging a sheet-like external insulating member 50 having a substantially cylindrical shape centered on the axis CL0 and having a foam layer 51 on the surface on the slot side, so as to face the inner circumferential surface 20a, an abutment step of abutting the external insulating member 50 against the inner circumferential surface 20a of the stator core 20, and a heating step of heating the external insulating member 50 abutting against the inner circumferential surface 20a (FIG. 4). This makes it possible to easily interpose the foam 52 between the inner circumferential surface 20a of the stator core 20 and the external insulating member 50. Therefore, the external insulating member 50 can be fixed to the inside of the stator core 20 via the foam 52, and the cooling oil in the slots can be prevented from leaking to the rotor 1 through the openings 221 with an inexpensive configuration.

[0047] (5) The contact step includes disposing a radially movable expansion jig 300 having a heating part 330 so as to face the external insulating member 50, and moving the heating part 330 in the radial direction (FIG. 6). The heating step includes heating the heating part 330. By using the expansion jig 30 in this manner, after the inner circumferential surface 20a of the stator core 20 and the foam layer 51 come into contact with each other, the foam layer 51 can be expanded radially outward while keeping the position of the external insulating member 50 constant or while pushing the external insulating member 50 radially outward. This allows the radial thickness of the foam 52 to be set uniform in the circumferential direction.

[0048] In the above embodiment, the inner peripheral surface 20a of the stator core 20 is provided with a plurality of slots 22 in the circumferential direction to form the inner peripheral surface 20a in an uneven shape in the circumferential direction, but the inner peripheral surface 20a may be further formed in an uneven shape in the axial direction. Fig. 10 is a cross-sectional view (a cross-sectional view cut along the axis CL0 in Fig. 1) of a portion of the stator core 20 as an example. As shown in Fig. 10, the stator core 20 is formed by alternately stacking steel plate portions 20A, 20B in the axial direction, each of which is made by stacking one or more electromagnetic steel plates.

[0049] FIG. 11A is a cross-sectional view taken along line AA in FIG. 10 showing the configuration of the steel plate portion 20A, and FIG. 11B is a cross-sectional view taken along line BB in FIG. 10 showing the configuration of the steel plate portion 20B. As shown in FIG. 11A and FIG. 11B, the protrusions 231 at the tip end portions of the teeth 23 are provided alternately in the circumferential direction. In addition, in the portion where the protrusions 231 are omitted, the tip end portions of the teeth 23 are located radially outwardly by the radial thickness of the protrusions 231 compared to the portion where the protrusions 231 are included. As a result, the inner peripheral surface 20a of the stator core 20 is formed in an uneven shape in the circumferential direction. That is, at the radially inner end portions of the steel plate portions 20A and 20B, the protrusions 26 having the protrusions 231 and the recesses 27 not having the protrusions 231 are provided alternately in the circumferential direction. In other words, the steel plate portions 20A and 20B each have a convex inner peripheral surface 26a and a concave inner peripheral surface 27a alternately in the circumferential direction. The convex inner circumferential surface 26 a and the concave inner circumferential surface 27 a form the inner circumferential surface 20 a of the stator core 20 .

[0050] The steel plate parts 20A and 20B have the same shape, and the steel plate part 20B is obtained by shifting the phase of the steel plate part 20A by one pitch of the slot 22. FIG. 10 corresponds to a cross-sectional view taken along the line XX in FIG. 11A and the line XX in FIG. 11B. That is, it corresponds to a cross-sectional view of the steel plate part 20A including the convex part 26 and the steel plate part 20B including the concave part 27. As shown in FIG. 10, the steel plate parts 20A and 20B are arranged in a state in which the concave part 27 and the convex part 26 are adjacent to each other in the axial direction. That is, the concave part 27 (first concave part) of the steel plate part 20A (first steel plate part) and the convex part 26 (second convex part) of the steel plate part 20B (second steel plate part) are arranged adjacent to each other, and the convex part 26 (first convex part) of the steel plate part 20A and the concave part 27 (second concave part) of the steel plate part 20B are arranged adjacent to each other. As a result, the inner circumferential surface 20a of the stator core 20 becomes uneven.

[0051] By stacking the recesses 27 and the protrusions 26 adjacent to each other in the axial direction in this manner, the foam 52 is formed in an uneven shape in the axial direction corresponding to the recesses 27 and the protrusions 26. This makes it possible to prevent the external insulating member 50 from moving in the axial direction, and to firmly fix the external insulating member 50 to the inside of the stator core 20 without misalignment. In addition, since the protrusions 231 at the tip ends of the teeth 23 are alternately provided in the circumferential direction, the width of the openings 221 of the slots 22 is increased. This makes it easy for the foam 52 to penetrate into the slots when the foam layer 51 is heated.

[0052] In the above embodiment, the openings 221 connected to the slots 22 are provided on the inner peripheral surface 20a of the stator core 20, but the slots 22 may be provided without the openings 221. FIG. 12 is a diagram showing an example of this. As shown in FIG. 12, the stator core 20 is provided with a substantially rectangular slot 22 that does not cross the inner peripheral surface 20a, and the slot 22 does not have an opening 221. The slot 22 in FIG. 12 is formed, for example, by punching. At the inner diameter side end of the tooth 23 between the circumferentially adjacent slots 22, a notch 28 is provided from the inner peripheral surface 20a of the stator core 20 toward the radially outward side. The notch 28 is formed so that its circumferential width increases as the distance from the inner peripheral surface 20a increases.

[0053] In the example of FIG. 11B, when the foam layer 51 on the surface of the external insulating member 50 is heated, the foam 52 enters the cutout 28 from the inner circumferential surface 20a of the stator core 20. This allows the foam 52 to engage with the cutout 28, and the external insulating member 50 can be fixed via the foam 52. In this case, since there is no opening 221 of the slot 22, the cooling oil in the slot does not leak from the opening 221. However, since the stator core 20 is formed by laminating electromagnetic steel sheets, there is a risk that the cooling oil in the slot may leak from the lamination surface of the electromagnetic steel sheets. Even if the cooling oil leaks from the lamination surface, the provision of the external insulating member 50 can prevent the cooling oil from leaking to the rotor.

[0054] In the above embodiment, the rotor 1 is rotatably disposed radially inside the stator 2, but the rotor 1 may be rotatably disposed radially outside the stator 2. That is, the stator 2 may be an inner stator instead of an outer stator. Fig. 13 is a cross-sectional view showing a schematic configuration of a rotating electric machine 100 in which the stator 2 for a rotating electric machine is configured as an inner stator.

[0055] As shown in Fig. 13, a rotor 1 having a substantially cylindrical shape centered on an axis line CL0 is disposed around a stator 2. Note that Fig. 13 illustrates only a portion of the rotor 1 in the circumferential direction. The rotor 1 is an outer rotor, and has a rotor core 10 and permanent magnets 11 embedded in the rotor core 10. The stator 2 has a stator core 20 and coils 21 disposed in slots 22 of the stator core 20. The coils 21 are wound around teeth 23 between circumferentially adjacent slots 22, for example, by concentrated winding.

[0056] An external insulating member 50 having a substantially cylindrical shape is disposed on the outside of the outer peripheral surface 20c of the stator core 20. A foam layer is formed in advance on the inner peripheral surface of the external insulating member 50, and when the foam layer is heated in contact with the outer peripheral surface 20c of the stator core 20, the foam 52 penetrates into the radially inner side of the outer peripheral surface 20c of the stator core 20 through the openings 221 of the slots 22. This allows the external insulating member 50 to be fixed to the stator core 20 via the foam 52 with the entire outer peripheral surface 20c of the stator core 20 covered by the external insulating member 50.

[0057] This embodiment can be modified in various ways. Several modified examples will be described below. In the above embodiment, the sheet-like external insulating member 50 is used by bending it, but the insulating member may not be in the form of a sheet but may be in the form of a film thinner than a sheet. In the above embodiment, the coil 21 is formed by arranging the conductor segments 211 in the slots 22, but the coil may be provided in the slot by concentrated winding or distributed winding. In the above embodiment, the cooling oil is guided to the slots 22 through the grooves 200 provided on the outer circumferential surface of the stator core 20 and the through holes 210 that penetrate the stator core 20 in the radial direction, but the configuration of the cooling medium supply unit is not limited to the above. The cooling medium (cooling oil) may be supplied from multiple points in the axial direction of the stator core 20.

[0058] In the above embodiment, the foam 52 is inserted into the inner peripheral surface 20a of the stator core 20 through the opening 221 of the slot 22, or the foam is inserted into the inner peripheral surface 20a of the stator core 20 through the notch 28. However, the foam introduction portion may have any configuration as long as the foam is provided on the inner peripheral surface (in the case of the outer stator) or the outer peripheral surface (in the case of the inner stator) of the stator core so as to be guided to the inside of the stator core. In the above embodiment, the internal insulating member 40 is formed by bending it into a substantially U-shape, but the configuration of the internal insulating member is not limited to the above. In the above embodiment, the foam layer 51 is provided on the surface of the external insulating member 50. However, the insulating member on which the foam layer 51 is provided (the above-mentioned external insulating member 50) is called an insulating base material, and the insulating base material and the foam layer may be collectively called an insulating member.

[0059] The above description is merely an example, and the present invention is not limited to the above-mentioned embodiment and modifications, as long as the features of the present invention are not impaired. The above-mentioned embodiment and one or more modifications can be arbitrarily combined, and modifications can be combined with each other. [Explanation of symbols]

[0060] 2 stator, 20 stator core, 20a inner peripheral surface, 20A, 20B steel plate portion, 21 coil, 22 slot, 23 teeth, 26 convex portion, 27 concave portion, 28 notch, 50 insulating member, 50A divided insulating member, 51 foam layer, 52 foam, 53 bent portion, 200 groove, 210 through hole, 221 opening, 300 expansion jig, 330 heating portion

Claims

1. A stator core having a circumferential surface centered on an axis line and having a plurality of circumferential slots extending in a radial direction; A coil disposed in the slot; a sheet-like or film-like insulating member configured to be substantially cylindrical about the axis so as to face the circumferential surface, The insulating member has a foam integrally therewith and fits into the inside of the stator core, The stator core is a cooling medium supply portion that introduces a cooling medium to the slot; a foam introduction portion provided on the peripheral surface so that the foam penetrates into the inside of the stator core.

2. 2. The stator for a rotating electric machine according to claim 1, A stator for a rotating electric machine, wherein the foam introduction portion is formed by an opening of the slot extending radially from the circumferential surface.

3. 3. The stator for a rotating electric machine according to claim 2, The insulating member is composed of a plurality of circumferentially divided insulating members that are divided and arranged in the circumferential direction, a stator for a rotating electric machine, wherein the divided insulating member has a bent portion bent radially from a circumferential end portion so as to be inserted into the slot through the opening.

4. 4. The stator for a rotating electric machine according to claim 2, a stator core for a rotating electric machine, the stator core being configured such that a circumferential width of the openings provided on the peripheral surface is smaller than a circumferential width of the slots.

5. 2. The stator for a rotating electric machine according to claim 1, The stator core further includes a plurality of teeth arranged in a circumferential direction to define the plurality of slots in the circumferential direction, A stator for a rotating electric machine, wherein the foam introduction portion is formed by a notch provided on a peripheral surface of the tooth.

6. 6. The stator for a rotating electric machine according to claim 5, a stator core for a rotating electric machine, the stator core being configured such that a circumferential width of the notch provided on the circumferential surface increases with increasing radial distance from the circumferential surface;

7. 2. The stator for a rotating electric machine according to claim 1, The stator core is configured by alternately laminating a first steel plate portion made of a single or a plurality of laminated electromagnetic steel plates and a second steel plate portion made of a single or a plurality of laminated electromagnetic steel plates in an axial direction, The peripheral surface includes a peripheral surface of the first steel plate portion and a peripheral surface of the second steel plate portion, The peripheral surface of the first steel plate portion has a first recessed portion recessed in the radial direction and a first protruding portion protruding in the radial direction alternately in the circumferential direction, The peripheral surface of the second steel plate portion has second recesses recessed in the radial direction and second protrusions protruding in the radial direction alternately in the circumferential direction, A stator for a rotating electric machine, characterized in that the first steel plate portion and the second steel plate portion are stacked so that the first recess and the second protrusion, and the second recess and the first protrusion, are adjacent in the axial direction, respectively.

8. A method for manufacturing a stator for a rotating electric machine, comprising: a stator core having a circumferential surface centered on an axis line and having a plurality of circumferential slots extending in a radial direction; and coils disposed in the slots, the stator being configured such that a cooling medium flows through the slots, the method comprising the steps of: a placement step of placing a sheet-like or film-like insulating member having a substantially cylindrical shape centered on the axis line and a foam layer provided on the surface of the insulating member on the slot side, so as to face the peripheral surface; a contact step of contacting the insulating member with the circumferential surface; and a heating step of heating the insulating member in contact with the circumferential surface.

9. 9. The method for manufacturing a stator for a rotating electric machine according to claim 8, The contact step includes disposing a jig having a heating portion and movable in a radial direction so as to face the insulating member, and moving the heating portion in the radial direction, The method for manufacturing a stator for a rotating electric machine, wherein the heating step includes heating the heating portion.

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