Rotary electric machine

Abstract

To provide a rotary electric machine capable of efficiently transferring heat of a coil to a stator core.SOLUTION: A rotary electric machine includes a stator, a rotor, a housing, and a cover member. The stator has a stator core and a coil. The stator core has a core back portion. The core back portion has an annular shape centered on a central axis. The coil is attached to the stator core. The coil is located radially inside the core back portion. The coil has a coil straight portion and a pair of coil end portions. The coil straight portion extends linearly along an axial direction. The pair of coil end portions protrudes in the axial direction from end faces on both axial sides of the stator core. The cover member is attached to the stator. The cover member comes into contact with the coil end portions and is pressed against the inner peripheral surface of the housing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a rotating electric machine. [Background technology]

[0002] In recent years, with the growing awareness of environmental considerations, aircraft in which propulsion fans are driven by rotating electric machines are being developed. Rotating electric machines for aircraft are required to be lightweight. For this reason, it is preferable to adopt an air-cooling type as a cooling mechanism for rotating electric machines for aircraft, and in this case, it is required to efficiently transfer heat from the coil to the stator core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-153230 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a rotating electric machine capable of efficiently transferring heat from a coil to a stator core. [Means for solving the problem]

[0005] A rotating electric machine according to an embodiment has a stator, a rotor, a housing, and a cover member. The stator is annular about a central axis. The rotor is located radially inside the stator. The rotor is supported for free rotation about the central axis. The housing accommodates the stator and the rotor. The housing is cylindrical. The cover member is attached to the stator. The stator has a stator core and a coil. The stator core has a core back portion. The core back portion is annular about the central axis. The coil is attached to the stator core. The coil is located radially inside the core back portion. The coil has a coil straight portion and a pair of coil end portions. The coil straight portion extends linearly along the axial direction. The pair of coil end portions protrude in the axial direction from end faces on both axial sides of the stator core. The cover member has a first cover portion. The first cover portion comes into contact with one of the coil end portions and bends the coil end portion toward the inner circumferential surface of the housing so as to come into contact with the inner circumferential surface of the housing. [Brief description of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view taken along a central axis of a rotating electric machine according to an embodiment; [Diagram 2] 1 is a schematic cross-sectional view of a stator included in a rotating electric machine according to an embodiment; [Diagram 3] 1 is a schematic diagram of a stator included in a rotating electric machine according to an embodiment, viewed from a radially inner side; [Figure 4] 4 is a cross-sectional view of the rotating electric machine according to the embodiment taken along line IV-IV in FIG. 3. [Diagram 5] FIG. 1 is a schematic diagram showing an example configuration of an aircraft. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a rotating electric machine according to an embodiment will be described with reference to the drawings. The design of a rotating electric machine can be changed as appropriate according to specifications, etc. Therefore, the shape, etc. of each member included in the rotating electric machine can be changed arbitrarily, and the shapes, numbers, etc. in the drawings are merely examples.

[0008] FIG. 1 is a cross-sectional view taken along a central axis J of a rotating electric machine 1 according to this embodiment. In the following description, the direction parallel to the central axis J is simply referred to as the "axial direction", the radial direction centered on the central axis J is simply referred to as the "radial direction", and the circumferential direction centered on the central axis J is simply referred to as the "circumferential direction θ". In addition, the axial direction AD, the radial direction RD, and the circumferential direction θ are illustrated in each figure as necessary. In each figure, the direction in which the arrow of the axial direction AD points is referred to as the "one axial side (+AD)", and the opposite direction is referred to as the "other axial side (-AD)". In addition, the direction in which the arrow of the radial direction RD points and which approaches the central axis J is referred to as the "radial inner side (+RD)", and the opposite direction is referred to as the "radial outer side (-RD)".

[0009] The rotating electric machine 1 includes, for example, an annular stator 30 centered on a central axis J, a rotor 20 located radially inside the stator 30, a cylindrical housing 10 that accommodates the stator 30 and the rotor 20, and a cover member 60 attached to the stator 30. The rotating electric machine 1 of this embodiment is an inner rotor type rotating electric machine in which the rotor 20 is located radially inside the stator 30.

[0010] The housing 10 has, for example, a housing body 12 that extends along the axial direction and surrounds the stator 30 from the radial outside, and bearing holders 11 that are fixed to the ends of the housing body 12 on one and the other axial sides, respectively.

[0011] The housing body 12 has, for example, a cylindrical portion 12a having a cylindrical shape centered on the central axis J, and a plurality of heat dissipation fins 12f protruding radially outward from the outer circumferential surface of the cylindrical portion 12a. The cylindrical portion 12a contacts the stator core 31 of the stator 30 at the inner circumferential surface 12b. Heat from the stator 30 is transferred to the cylindrical portion 12a and then transferred from the cylindrical portion 12a to the heat dissipation fins 12f. The plurality of heat dissipation fins 12f are arranged, for example, in the circumferential direction with a small gap therebetween. The gaps between the heat dissipation fins 12f open, for example, on both sides in the axial direction. The rotating electric machine 1 is mounted on the aircraft 90 in a position in which the central axis J is parallel to the traveling direction of the aircraft 90. As the aircraft 90 flies, air passes through the gaps between the heat dissipation fins 12f, thereby cooling the heat dissipation fins 12f.

[0012] The bearing holder 11 is, for example, in the shape of a disk centered on the central axis J. The pair of bearing holders 11 each cover an opening on both axial sides of the cylindrical portion 12a. The bearing holder 11 has, for example, a fixed portion 11a, a tapered portion 11b, and a bearing holding portion 11c. The fixed portion 11a is, for example, in the shape of an annular plate centered on the central axis J. The fixed portion 11a is fixed, for example, to an end face facing the axial direction of the cylindrical portion 12a using a bolt (not shown).

[0013] The tapered portion 11b has, for example, a conical shape. The tapered portion 11b extends from the fixed portion 11a toward the inside in the radial direction and inclined toward the stator 30 in the axial direction AD. The tapered portion 11b is provided with, for example, a plurality of introduction holes 11h. The introduction holes 11h penetrate the tapered portion 11b in the axial direction AD. The plurality of introduction holes 11h communicate the internal space of the housing 10 with the external space. Air from the external space is introduced into the internal space of the housing 10 through, for example, the introduction hole 11h of one of the bearing holders 11, and cools the rotor 20 and the stator 30. In addition, the air warmed by the rotor 20 and the stator 30 is guided to the outside of the housing 10 through the introduction hole 11h of the other bearing holder 11. Incidentally, the tapered portion 11b is not necessarily required, and the fixed portion 11a and the bearing holding portion 11c may be connected on a flat surface.

[0014] The bearing holding portion 11c has, for example, a cylindrical shape centered on the central axis J. A bearing B is held on the inner peripheral surface of the bearing holding portion 11c. The bearing B supports the shaft 21 of the rotor 20 so as to be rotatable.

[0015] The rotor 20 is supported by the housing 10 so as to be rotatable about a central axis J. The rotor 20 includes, for example, a shaft 21 having a central axis J, a hub member 23, a rotor core 27, a magnet unit 25, and a cover 26.

[0016] The shaft 21 is, for example, columnar and extends in the axial direction about a central axis J. The hub member 23 is, for example, cylindrical and has a sufficient thickness in the radial direction. The hub member 23 is provided with, for example, a plurality of through holes 23h that penetrate in the axial direction. The hub member 23 is fixed, for example, to the outer circumferential surface of the shaft 21. In addition, a rotor core 27 is fixed, for example, to the outer circumferential surface of the hub member 23.

[0017] The plurality of through holes 23h allows air to pass through. As described above, the housing 10 is provided with the plurality of introduction holes 11h that communicate the internal space of the housing 10 with the external space. A portion of the air that has entered the internal space of the housing 10 through the introduction holes 11h cools the rotor 20 as it passes through the through holes 23h.

[0018] The rotor core 27 is made of a magnetic material. For example, the rotor core 27 is a laminated steel plate formed by stacking a plurality of electromagnetic steel plates in the axial direction. The rotor core 27 provided in the rotating electric machine 1 according to this embodiment is, for example, cylindrical. A magnet unit 25 is disposed on the outer circumferential surface of the rotor core 27.

[0019] The magnet unit 25 has, for example, a circular ring shape. The magnet unit 25 can be fixed to the outer circumferential surface of the rotor core 27 by a joining means such as adhesive. The rotor 20 provided in the rotating electric machine 1 according to this embodiment is a surface magnet type in which the magnet unit 25 directly faces the stator 30 magnetically. The configuration of the rotor 20 is not limited to this embodiment, and may be, for example, an embedded magnet type.

[0020] The magnet unit 25 has a magnet with its S pole facing radially outward and a magnet with its N pole facing radially outward, and these are arranged alternately in the circumferential direction. That is, the magnet unit 25 has a plurality of magnets whose magnetization directions alternate in the circumferential direction. The magnet unit 25 can be fixed to the outer surface of the rotor core 27 by, for example, adhesion or other means. The magnet unit 25 is covered by a cylindrical cover 26. The cover 26 is made of a material that is unlikely to affect the magnetic force of the magnet unit 25.

[0021] The stator 30 surrounds the rotor 20 from the radial outside. The stator 30 has, for example, a stator core 31, a coil 40, and an insulating member (not shown). The insulating member (not shown) insulates the coil 40 from the stator core 31. This insulating member may be, for example, insulating paper. Furthermore, this insulating member may be any of resin, adhesive, glass cloth, insulating paper, Kapton tape, etc., and may also be other members as long as they are insulating members.

[0022] Fig. 2 is a schematic cross-sectional view of the stator 30 included in the rotary electric machine 1 according to this embodiment. In Fig. 2, the circumferential direction is shown as a straight line.

[0023] The stator core 31 is, for example, a laminated steel plate formed by stacking a plurality of electromagnetic steel plates in the axial direction. The outer peripheral surface of the stator core 31 contacts the inner peripheral surface 12b of the cylindrical portion 12a of the housing 10. Heat from the stator 30 is transferred from the outer peripheral surface of the stator core 31 to the housing 10 and dissipated by the heat dissipation fins 12f.

[0024] The stator core 31 has, for example, a core back portion 32 and a plurality of protruding portions 33. The stator core 31 is made of a magnetic material.

[0025] The core back portion 32 is, for example, an annular shape centered on the central axis J. The core back portion 32 has a support surface 32a facing radially inward. The coil 40 is disposed radially inside the core back portion 32. The support surface 32a supports the coil 40 from the radially outside, for example, by sandwiching an insulating member (not shown). The "insulating member provided between the coil 40 and the support surface 32a" may be an insulating material selected from the same insulating material group as the "insulating member 50 disposed between the coil end portion and the inner peripheral surface of the housing" described later. The "insulating member provided between the coil 40 and the support surface 32a" and the "insulating member 50 disposed between the coil end portion and the inner peripheral surface of the housing" may be made of the same material or different materials.

[0026] The multiple protrusions 33 protrude radially inward from the support surface 32a of the core back portion 32. The protrusions 33 have, for example, a rib shape extending along the axial direction. The multiple protrusions 33 are arranged in the circumferential direction. The multiple protrusions 33 protrude radially inward from the support surface 32a of the core back portion 32. A winding range C in which the coil 40 is arranged is provided between the protrusions 33 adjacent to each other in the circumferential direction. That is, the multiple protrusions 33 define the winding range C.

[0027] The stator core 31 included in the rotating electric machine 1 according to this embodiment has protruding parts 33 that circumferentially partition an area in which the coils 40 are arranged, thereby making it possible to suppress circumferential positional deviation of the coils 40. Furthermore, since the protruding parts 33 are made of a magnetic material, magnetic flux formed in the radial direction between the rotor 20 and the stator 30 when the rotating electric machine 1 is driven is concentrated at the protruding parts 33 and is likely to pass through. According to this embodiment, it becomes difficult for magnetic flux to pass through the coils 40, making it possible to suppress copper loss occurring in the coils 40 and to improve the driving efficiency of the rotating electric machine 1.

[0028] 3 is a schematic diagram of the stator 30 as viewed from the radially inner side. Note that the above-mentioned FIG. 2 is a cross-sectional view taken along line II-II in FIG.

[0029] As shown in FIG. 3, the coil 40 is attached to the stator core 31. The coil 40 has a coil straight portion 48 disposed in the winding range C, and a pair of coil end portions 49 that respectively protrude in the axial direction from end faces 31a on both axial sides of the stator core 31. The coil straight portion 48 is located on the radially inner side (+RD) of the core back portion 32. The coil straight portion 48 extends linearly along the axial direction AD between the protruding portions 33 adjacent to each other in the circumferential direction. The pair of coil end portions 49 are each connected to both axial sides of the coil straight portion 48. The coil end portions 49 are bent in a hairpin shape to connect the ends of the two coil straight portions 48 to each other.

[0030] The coils 40 are classified into coils of multiple phases. Different-phase AC currents flow through the coils 40 of different phases. The coils 40 included in the rotating electric machine 1 according to this embodiment include three-phase coils 40, and AC currents with phases shifted by 120° flow through these coils 40. Note that, in order to illustrate a three-phase AC rotating electric machine, the coils 40 are classified into three phases here, but the number of phases is not limited to this embodiment. In addition, the phase difference of the AC currents flowing through the coils 40 of each phase is appropriately changed depending on the number of phases. The coils 40 included in the rotating electric machine 1 according to this embodiment are configured, for example, by distributed winding in which the coils 40 of different phases are shifted in the circumferential direction and overlap in the radial direction.

[0031] As shown in FIG. 2, the coil 40 includes a plurality of wire bundles 42. In the stator 30 included in the rotating electric machine 1 according to the present embodiment, a plurality of wire bundles 42 are arranged in the region between a pair of protrusions 33. Each wire bundle 42 is formed by bundling a plurality of coil wires 42e. That is, the coil 40 is formed by bundling a plurality of coil wires 42e. The coil wires 42e may be either round wires or square wires, or may have other cross-sectional shapes. The wire bundles 42 are wound around the protrusions 33 in a loop shape a plurality of times to form the coil 40. FIG. 2 shows an example in which a plurality of wire bundles 42 are arranged in the region between the pair of protrusions 33, but the number of wire bundles 42 arranged in the region between the protrusions 33 can be arbitrarily changed depending on the coil design.

[0032] 1, the cover member 60 is disposed inside the housing 10. The cover member 60 is preferably made of a material having excellent insulating properties. In this embodiment, the cover member 60 is made of a ceramic material.

[0033] The cover member 60 has a pair of first cover portions 61A, 61B and a second cover portion 62.

[0034] The first cover part 61A located on one axial side (+AD) of the pair of first cover parts 61A, 61B is located on one axial side and radially inside of one of the pair of coil end parts 49 located on the one axial side (+AD) of the pair of coil end parts 49. The first cover part 61B located on the other axial side (-AD) of the pair of first cover parts 61A, 61B is located on the other axial side and radially inside of the other of the pair of coil end parts 49 located on the other axial side (-AD) of the pair of coil end parts 49. In this embodiment, the pair of first cover parts 61A, 61B have symmetrical shapes in the axial direction, but they do not need to have strictly symmetrical shapes, and misalignment is allowed within a range that does not affect the design, performance, etc. of the rotating electric machine 1.

[0035] FIG. 4 is a cross-sectional view of the rotating electric machine 1 taken along line IV-IV in FIG. 4 illustrates only one of the pair of first cover parts 61A, 61B, which is located on one axial side (+AD). In the following description, the shape of one of the first cover parts 61A will be described with reference to FIG. 4. In this embodiment, the other first cover part 61B has a shape that is inverted in the axial direction compared to the first cover part 61A to be described, and therefore a description thereof will be omitted. Note that this embodiment is merely an example, and the first cover part 61B may have a shape that is deviated from the strictly symmetrical shape as long as it does not affect performance, etc.

[0036] The first cover portion 61A has, for example, a uniform cross-sectional shape and extends in the circumferential direction θ around the central axis J. The first cover portion 61A has, for example, a cover main body portion 61m, a first joint portion 61a, and a first connecting portion 61g. The first cover portion 61A is in contact with at least the second cover portion 62 and the housing main body 12. The first cover portion 61A provided in the rotating electric machine 1 according to this embodiment is in contact with the second cover portion 62 at the first connecting portion 61g, and in contact with the housing main body 12 at the cover main body portion 61m.

[0037] When observed in a cross section parallel to one axial side (+AD), the cover body portion 61m is preferably a tapered plate extending radially outward (-RD) toward one axial side (+AD). The cover body portion 61m axially covers the end face 31a of the stator core 31 facing the axial direction AD. The thickness dimension of the cover body portion 61m gradually increases toward one axial side. This makes it easier to ensure a sufficient thickness of the first joint portion 61a described later and to ensure sufficient joint strength with the housing 10. Note that the preferred shape of the cover body portion 61m is a tapered shape, but the shape of the cover body portion 61m is not limited to this embodiment.

[0038] The cover body portion 61m is in contact with the housing body 12. The cover body portion 61m has a pressing surface 61f facing the other axial side (-AD) and the radially outward (-RD). That is, the first cover portion 61A has the pressing surface 61f. As long as the second cover portion 62 is in contact with the housing body 12, the shape of the cover body portion 61m is not important. It is preferable that the pressing surface 61f is a surface that inclines toward the radially outward (-RD) as it approaches the one axial side (+AD). That is, the pressing surface 61f inclines toward the radially outward (-RD) as it moves away from the stator core 31 in the axial direction. The pressing surface 61f faces the end surface 31a of the stator core 31 facing the axial direction in the axial direction. The pressing surface 61f also faces and comes into contact with the coil end portion 49 in the axial direction AD and the radial direction RD. When the coil end portion 49 comes into contact with the pressing surface 61f, it is bent radially outward (-RD) and pressed against the inner circumferential surface 12b of the housing 10. As a result, heat from the coil end portion 49 is released to the outside via the housing 10.

[0039] Moreover, the first cover part 61A included in the rotating electric machine 1 according to this embodiment comes into contact with the coil end part 49 at a pressing surface 61f. Therefore, a part of the heat of the coil end part 49 is transferred to the first cover part 61A and dissipated to the outside via the first cover part 61A. Furthermore, this heat is dissipated to the outside from the first cover part 61A via the housing 10. In other words, the heat of the coil end part 49 is dissipated to the outside via a path that is directly transferred to the housing 10, a path that is via the first cover part 61A, and a path that is transferred from the first cover part 61A to the housing 10.

[0040] In this specification, "contact" includes not only the case where one member is in direct contact with another member, but also the case where one member and another member are in thermal contact via an intervening object. Here, "thermal contact" refers to a state in which heat from one member is rapidly transferred to another member. In addition, "rapid transfer of heat" between members means that the rate of heat transfer is at least faster than when the members are separated from each other by an air layer.

[0041] An insulating member 50 is disposed between the coil end portion 49 and the inner circumferential surface 12b of the housing 10 to insulate the coil end portion 49 from the housing 10. The insulating member 50 may be, for example, an insulating resin member. The insulating member 50 may be any of resin, adhesive, glass cloth, insulating paper, Kapton tape, and the like, and may also be other insulating members. Also, instead of or in addition to disposing the insulating member 50, an insulating coating may be provided on the inner circumferential surface 12b of the housing 10 or on the surface of the coil wire 42e.

[0042] The first joint portion 61a is provided at an end portion on one axial side (+AD) of the cover main body portion 61m. The first joint portion 61a provided in the rotating electric machine 1 according to this embodiment contacts the inner circumferential surface 12b of the cylindrical portion 12a of the housing 10. The first joint portion 61a can be fixed to the inner circumferential surface 12b of the cylindrical portion 12a by, for example, adhesion or other means. In this embodiment, it is preferable that the first joint portion 61a and the cylindrical portion 12a are airtightly joined over the entire circumference in the circumferential direction. Therefore, the first cover portion 61A suppresses the passage of air at the boundary between the first joint portion 61a and the cylindrical portion 12a. Note that, in this embodiment, a case where the first joint portion 61a is directly adhesively fixed to the inner circumferential surface 12b is illustrated, but the first joint portion 61a may be fixed to the inner circumferential surface 12b of the housing 10 by other means.

[0043] The first connecting portion 61g is provided at an end portion of the cover main body portion 61m on the other axial side (-AD). The first connecting portion 61g is connected to the second cover portion 62. The first connecting portion 61g has, for example, a first end face 61c and a second end face 61d facing the other axial side (-AD) and a first connecting face 61e facing the radially outward side (-RD). The first end face 61c, the second end face 61d, and the first connecting face 61e are arranged in a stepped shape. Therefore, the first cover portion 61A and the second cover portion 62 are stepped at the first connecting portion 61g. The first end face 61c and the second end face 61d are flat surfaces perpendicular to the central axis J. Moreover, the first end face 61c and the second end face 61d extend, for example, in an annular shape centered on the central axis J. The first end face 61c is located on the other axial side (-AD) and radially inward (+RD) than the second end face 61d. The first connecting surface 61e is, for example, a cylindrical surface extending in the circumferential direction about the central axis J. The first connecting surface 61e connects an end portion on the radially outer side (-RD) of the first end face 61c and an end portion on the radially inner side (+RD) of the second end face 61d.

[0044] The second cover portion 62 is located radially inward (+RD) of the stator core 31 and the coil straight portion 48. As shown in FIG. 3, the second cover portion 62 preferably has a plurality of divided portions 62a. The divided portions 62a are arranged side by side along the circumferential direction. The divided portions 62a are each located between the protruding portions 33. The divided portions 62a are, for example, plate-shaped and extend along the axial direction perpendicular to the radial direction. The total length of the divided portions 62a in the axial direction AD is slightly greater than the total length of the stator core 31 in the axial direction AD. Both axial end portions of the divided portions 62a (second connecting portions 62g described later) each protrude toward the end face 31a of the stator core 31 facing the axial direction.

[0045] As shown in FIG. 2, the surface of the divided portion 62a facing the radially inward (+RD) faces the support surface 32a of the core back portion 32 in the radial direction RD. The coil straight portion 48 is disposed between the core back portion 32 and the second cover portion 62 in the radial direction RD. The divided portion 62a presses the coil straight portion 48 toward the core back portion 32. That is, the second cover portion 62 applies a surface pressure to the coil straight portion 48 to press it against the core back portion 32. As a result, the coil straight portion 48 comes into close contact with the support surface 32a of the core back portion 32. In addition, since the coil 40 is composed of a plurality of coil wires 42e, some of the coil wires 42e are expanded in the circumferential direction by applying a surface pressure from the second cover portion 62 to the radially inward (+RD). As a result, some of the coil wires 42e are pressed against the protruding portion side surface 33a of the protruding portion 33. That is, according to the present embodiment, the contact area between the coil straight portion 48 and the stator core 31 is increased, and the heat of the coil straight portion 48 is easily transferred to the stator core 31. This makes it possible to efficiently cool the coil 40.

[0046] As shown in FIG. 3, the divided portion 62a has a pair of second joint portions 62b located at both ends in the circumferential direction, and a pair of second connecting portions 62g located at both ends in the axial direction.

[0047] As shown in FIG. 2, the second joint 62b contacts the protrusion side surface 33a of the protrusion 33 of the housing 10, which faces the circumferential direction. The second joint 62b can be fixed to the protrusion side surface 33a by, for example, adhesion or other means. In this embodiment, the second joint 62b and the protrusion side surface 33a are preferably airtightly joined over the entire axial length. Therefore, the second cover portion 62 suppresses air passage at the boundary between the second joint 62b and the protrusion 33. Note that, although the present embodiment illustrates a case in which the second joint 62b is directly adhesively fixed to the protrusion side surface 33a, the second joint 62b may be fixed to the protrusion side surface 33a by other means.

[0048] As shown in FIG. 3, the pair of second connecting parts 62g are provided on both axial sides of the dividing part 62a and have a shape symmetrical in the axial direction. Note that this embodiment is an example, and the pair of second connecting parts 62g may have a shape that is deviated from a strictly symmetrical shape within a range that does not affect performance, etc. One of the pair of second connecting parts 62g on one axial side is connected to the first cover part 61A on one axial side of the pair of first cover parts 61A, 61B. The other of the pair of second connecting parts 62g on the other axial side is connected to the first cover part 61B on the other axial side of the pair of first cover parts 61A, 61B. In the following description, only one of the pair of second connecting parts 62g on one axial side will be described, and the other, which has a shape inverted in the axial direction, will be omitted.

[0049] As shown in FIG. 4, the second connecting portion 62g has, for example, a third end face 62c and a fourth end face 62d facing one axial side (+AD) and a second connecting face 62e facing the radially inward (+RD). The third end face 62c, the fourth end face 62d, and the second connecting face 62e are arranged in a stepped shape. The third end face 62c and the fourth end face 62d are flat faces perpendicular to the central axis J. In addition, the third end face 62c and the fourth end face 62d extend, for example, in an annular shape centered on the central axis J. The third end face 62c is located on the other axial side (-AD) and on the radially inward (+RD) of the fourth end face 62d. The second connecting face 62e is, for example, a cylindrical surface extending in the circumferential direction centered on the central axis J. The second connecting surface 62e connects the radially outer (-RD) end of the third end surface 62c and the radially inner (+RD) end of the fourth end surface 62d.

[0050] In a state where the first connecting portion 61g and the second connecting portion 62g are connected to each other, the second connecting portion 62g is located radially inward of the first connecting portion 61g. Therefore, the second cover portion 62 is restricted from moving radially outward by the first cover portion 61A. In addition, the first end face 61c and the third end face 62c face each other, the second end face 61d and the fourth end face 62d face each other, and the first connecting face 61e and the second connecting face 62e face each other.

[0051] The first end face 61c and the third end face 62c, the second end face 61d and the fourth end face 62d, and the first connecting face 61e and the second connecting face 62e are preferably fixed to each other by using an adhesive or the like. In this embodiment, the boundary between the first cover part 61A and the second cover part 62 is preferably prevented from passing air by an adhesive. In this embodiment, it is more preferable that the first connecting part 61g and the second connecting part 62g are airtightly joined over the entire length in the circumferential direction. In this embodiment, it is also more preferable that the boundary between the axial end face of the protrusion 33 and the first cover part 61A is airtightly joined by an adhesive.

[0052] As shown in FIG. 3, the split portion 62a of the rotating electric machine 1 according to this embodiment has second connecting portions 62g located at the ends on one axial side (+AD) and the other axial side (-AD), and each second connecting portion 62g is joined to the first cover portions 61A and 61B. Also, as shown in FIG. 4, the second connecting portions 62g on both axial sides are respectively located on the radial outside (-RD) of the first connecting portion 61g. Therefore, the split portion 62a is restricted from moving radially inward (+RD) at both ends in the axial direction AD. Furthermore, the split portion 62a receives forces from the first cover portions 61A and 61B toward the radial outside (-RD) at both ends in the axial direction AD. This allows the split portion 62a to stably apply surface pressure to the coil straight portion 48.

[0053] 1, the interior space of the housing 10 is divided into inner and outer spaces in the radial direction by the cover member 60. Here, of the interior space of the housing 10 divided by the cover member 60, the space radially outward (-RD) from the cover member 60 is referred to as a first space A1, and the space radially inward (+RD) from the cover member 60 is referred to as a second space A2. The coil 40 is disposed in the first space A1. The rotor 20 is disposed in the second space A2.

[0054] The second space A2 in the rotating electric machine 1 according to this embodiment communicates with the external space of the housing 10 through the introduction hole 11h. Therefore, when the aircraft 90 flies, air is introduced into the second space A2 through the introduction hole 11h, and the rotor 20 is cooled by the flow of this air. On the other hand, the passage of air through the first space A1 in the rotating electric machine 1 according to this embodiment is suppressed by the housing 10, the stator core 31, and the cover member 60. Therefore, even if the aircraft 90 rises into the sky, the air pressure in the first space A1 in the rotating electric machine 1 mounted on the aircraft 90 is kept higher than the air pressure in the second space A2. It is generally known that the discharge phenomenon of the coil 40 is more likely to occur at low pressure. According to this embodiment, the air pressure in the first space A1 is kept higher than the air pressure in the second space A2, so that the discharge in the coil 40 in the sky can be suppressed. In addition, in this embodiment, the coil 40 cannot be directly air-cooled by arranging the coil 40 in the first space A1. In contrast, in this embodiment, the first cover parts 61A, 61B press the coil end parts 49 against the inner circumferential surface 12b of the housing 10, and the second cover part 62 presses the coil straight parts 48 against the stator core 31. This allows the heat of the coil 40 to be efficiently cooled to the outside via the stator core 31 and the housing 10. This makes it possible to prevent the temperature of the coil 40 from becoming too high, even if it is not possible to cool the coil 40 directly.

[0055] The configuration and effects of the rotating electric machine 1 of this embodiment will be summarized below. The rotating electric machine 1 of this embodiment includes a stator 30, a rotor 20, a housing 10, and a cover member 60. The stator 30 is annular about a central axis J. The rotor 20 is located on the radially inner side (+RD) of the stator 30. The rotor 20 is supported so as to be rotatable about the central axis J. The housing 10 is cylindrical and accommodates the stator 30 and the rotor 20. The cover member 60 is attached to the stator 30. The stator 30 includes a stator core 31 and a coil 40. The stator core 31 includes a core back portion 32 that is annular and centered on the central axis J. The coil 40 is attached to the stator core 31. The coil 40 includes a coil straight portion 48 and a pair of coil end portions 49. The coil straight portion 48 is located on the radially inner side (+RD) of the core back portion 32 and extends linearly along the axial direction. The pair of coil end portions 49 protrude in the axial direction from end faces on both axial sides of the stator core 31. The cover member 60 has a first cover portion 61A. The first cover portion 61A contacts one of the coil end portions 49 and is bent toward the inner circumferential surface 12b of the housing 10 to contact the inner circumferential surface 12b of the housing.

[0056] Generally, the coil end portion 49 generates a large amount of heat because the coil wire 42e is densely packed. According to the above-mentioned configuration, the first cover portion 61A bends the coil end portion 49 to contact the inner circumferential surface 12b of the housing 10. This makes it possible to transfer the heat of the coil end portion 49 to the housing 10. In addition, because the first cover portion 61A contacts the coil end portion 49, some of the heat of the coil end portion 49 transfers to the housing 10 via the first cover portion 61A. This makes it possible to cool the coil end portion 49 and prevent the temperature of the coil end portion 49 from becoming too high.

[0057] In the rotating electric machine 1 of this embodiment, the cover member 60 has a second cover portion 62. The second cover portion 62 is located on the radially inner side (+RD) of the coil straight portion 48. The second cover portion 62 applies a surface pressure on the radially outer side (-RD) to the coil straight portion 48 to bring the second cover portion 62 into contact with the stator core.

[0058] According to this configuration, the coil straight portion 48 is pressed against the stator core 31, making it easier to ensure a wide contact area between the coil straight portion 48 and the stator core 31. This allows the heat of the coil straight portion 48 to be transferred to the stator core 31, allowing the coil straight portion 48 to be efficiently cooled. The heat transferred to the stator core 31 is dissipated to the outside via the housing 10.

[0059] In the rotating electric machine 1 of this embodiment, the cover member 60 has a pair of first cover parts 61A, 61B. The pair of first cover parts 61A, 61B are located axially outward of the coil end parts 49 on one axial side (+AD) and the other axial side (-AD), respectively. The pair of first cover parts 61A, 61B are located radially inward (+RD) of the end parts of the second cover part 62 on one axial side and the other axial side, respectively.

[0060] According to this configuration, the pair of first cover parts 61A, 61B suppress detachment of the second cover part 62 to the radially inward direction (+RD). In addition, the pair of first cover parts 61A, 61B can press the second cover part 62 against the coil straight part 48, thereby increasing the reliability of contact between the second cover part 62 and the coil straight part 48.

[0061] In the rotating electric machine 1 of this embodiment, the stator core 31 has a plurality of protruding portions 33. The plurality of protruding portions 33 protrude radially inward (+RD) from the core back portion 32 and are aligned in the circumferential direction θ. The coil straight portion 48 extends along the axial direction AD between the protruding portions 33 adjacent to each other in the circumferential direction. The second cover portion 62 has a plurality of divided portions 62a. The plurality of divided portions 62a are each located between the protruding portions 33.

[0062] According to this configuration, since the stator core 31 has the protruding portions 33, it is possible to reduce the magnetic flux passing through the coil 40 and suppress copper loss occurring in the coil straight portions 48 between the protruding portions 33. Furthermore, by arranging the split portions 62a between the protruding portions 33, it is possible to press the coil straight portions 48 between the protruding portions 33 against the stator core 31 by the respective split portions 62a. As a result, it is possible to efficiently transfer heat from the coil straight portions 48 to the stator core 31.

[0063] In the rotating electric machine 1 of this embodiment, the cover member 60 has a second cover portion 62 and a pair of first cover portions 61A, 61B. The second cover portion 62 is located radially inward (+RD) of the coil straight portion 48. The pair of first cover portions 61A, 61B are connected to the ends of both axial sides of the second cover portion 62. The pair of first cover portions 61A, 61B are located axially outward of the coil end portion 49 on one axial side (+AD) and the other axial side (-AD), respectively. The cover member 60 divides the inside of the housing 10 into a first space A1 and a second space A2. The first space A1 is a space located radially outward from the cover member 60. The second space A2 is a space located radially inward from the cover member 60. The coil 40 is disposed in the first space A1. The rotor 20 is disposed in the second space A2.

[0064] According to this configuration, the cover member 60 divides the inside of the housing 10 into a first space A1 in which the coil 40 is disposed, and a second space A2 in which the rotor 20 is disposed. This allows the periphery of the coil 40 and the periphery of the rotor 20 to be in different states. More specifically, by sealing the first space A1, the air pressure in the first space A1 can be maintained even in the air, thereby suppressing discharge of the coil 40. On the other hand, by opening the second space A2 to the outside air and introducing the outside air into the second space A2, it becomes possible to cool the rotor 20 disposed in the second space A2.

[0065] In the rotating electric machine 1 of this embodiment, the first cover portion 61A has a pressing surface 61f that comes into contact with the coil end portion 49. The pressing surface 61f inclines radially outward (-RD) as it moves away from the stator core 31 in the axial direction AD.

[0066] According to this configuration, by having a tapered pressing surface 61f, by inserting the first cover part 61A into the inside of the housing 10 in the axial direction AD, it is possible to press the coil end part 49 evenly against the inner surface 12b of the housing 10 in the circumferential direction.

[0067] In the rotating electric machine 1 of this embodiment, the cover member 60 is made of a ceramic material. Ceramic materials that can be used for the cover member 60 include, for example, silicon nitride (SiN), aluminum nitride (AlN), silica (SiO2), alumina (Al2O3), or a composite material of ceramic and metal.

[0068] Generally, ceramic materials have excellent insulating properties. According to the above-mentioned configuration, since the cover member 60 has insulating properties, the cover member 60 can be brought into direct contact with the coil 40. Furthermore, according to the above-mentioned configuration, since the cover member 60 has excellent thermal conductivity, it can receive heat from the coil 40 and cool the coil 40. The heat received by the cover member 60 from the coil 40 can be released to the outside via the housing 10.

[0069] In the rotating electric machine 1 of this embodiment, an insulating member 50 is interposed between the coil end portion 49 and the inner circumferential surface 12b of the housing 10.

[0070] According to this configuration, even when the housing 10 is made of a metal material with high thermal conductivity, discharge from the coil end portion 49 to the housing 10 can be suppressed.

[0071] In the rotating electric machine 1 of the present embodiment, the case where the stator core 31 has the protruding portion 33 has been described, but the stator core 31 may or may not have the protruding portion 33.

[0072] According to at least one of the embodiments described above, by having a cover member 60 that brings the coil end portion 49 into contact with the inner surface 12b of the housing 10, a rotating electric machine 1 can be provided that can efficiently transfer heat from the coil 40 to the housing 10.

[0073] The rotating electric machine can be mounted on various drive objects such as automobiles, trains, and aircraft. Fig. 5 is a schematic diagram of an aircraft 90 as an example of a drive object on which the rotating electric machine 1 is mounted. The aircraft 90 is a hybrid aircraft propelled by a combination of a jet engine 91 and the rotating electric machine 1. The aircraft 90 has a pair of jet engines 91 and four rotating electric machines 1. The jet engines 91 are provided on main wings 98. The jet engines 91 generate thrust by exhausting air rearward.

[0074] The four rotating electric machines 1 are classified into two power generating rotating electric machines 1A and two drive rotating electric machines 1B. The power generating rotating electric machines 1A are each connected to the main shaft of a jet engine 91. The power generating rotating electric machine 1A generates electricity by the jet engine 91. Meanwhile, the drive rotating electric machine 1B is disposed below the vertical tail 99. The drive rotating electric machine 1B rotates a propulsion fan 93 to send air rearward and generate thrust. The drive rotating electric machine 1B is driven by electric power generated by the power generating rotating electric machine 1A. Note that if the power generating rotating electric machine 1A generates surplus electric power, this electric power may be charged into a battery and used when necessary.

[0075] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0076] Reference Signs List 1... rotating electric machine, 10... housing, 12b... inner circumferential surface, 20... rotor, 30... stator, 31... stator core, 31a... end surface, 32... core back portion, 33... protruding portion, 40... coil, 48... coil straight portion, 49... coil end portion, 50... insulating member, 60... cover member, 61f... pressing surface, 61A, 61B... first cover portion, 62... second cover portion, 62a... division portion, A1... first space, A2... second space, AD... axial direction, J... central axis, RD... radial direction, θ... circumferential direction

Claims

1. An annular stator centered on a central axis; a rotor located radially inside the stator and supported rotatably about the central axis; a cylindrical housing that accommodates the stator and the rotor; a cover member attached to the stator, The stator includes: a stator core having an annular core back portion centered on the central axis line; a coil attached to the stator core; The coil is a coil straight portion located radially inside the core back portion and extending straight along the axial direction; a pair of coil end portions protruding in the axial direction from end faces on both axial sides of the stator core, the cover member has a first cover portion that contacts one of the coil end portions and bends the coil end portion toward an inner circumferential surface of the housing to contact the inner circumferential surface of the housing, Rotating electric motor.

2. the cover member has a second cover portion located radially inside the coil straight portion and applying a radially outward surface pressure to the coil straight portion to bring the coil straight portion into contact with the stator core, The rotating electric machine according to claim 1 .

3. the cover member has a pair of the first cover portions located axially outwardly of the coil end portions on one axial side and the other axial side, The pair of first cover portions are located radially inside one and the other axial end portions of the second cover portion, respectively. The rotating electric machine according to claim 2 .

4. The stator core has a plurality of protruding portions protruding radially inward from the core back portion and arranged in a circumferential direction, The coil straight portion extends along the axial direction between the protruding portions adjacent to each other in the circumferential direction, The second cover portion has a plurality of divided portions each located between the protruding portions. The rotating electric machine according to claim 2 .

5. The cover member is A second cover portion located radially inside the coil straight portion; a pair of the first cover portions connected to both axial ends of the second cover portion and positioned axially outward of the coil end portions on one and the other axial sides, The cover member divides an interior of the housing into a first space located radially outward from the cover member and a second space located radially inward from the cover member, The coil is disposed in the first space, The rotor is disposed in the second space. The rotating electric machine according to claim 1 .

6. the first cover portion has a pressing surface that contacts the coil end portion, The pressing surface is inclined radially outward as it moves away from the stator core in the axial direction. The rotating electric machine according to claim 1 .

7. The cover member is made of a ceramic material. The rotating electric machine according to any one of claims 1 to 6.

8. An insulating member is interposed between the coil end portion and an inner circumferential surface of the housing. The rotating electric machine according to claim 1 .

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