Rotor, rotating electric machine, and drive device

Abstract

To provide a rotor capable of efficiently cooling a magnet.SOLUTION: A rotor includes a plurality of magnets that form a plurality of magnetic poles arranged in the circumferential direction, a rotor core 24 that holds the magnets, and a cap member 4 that is arranged opposite one axial end face of the rotor core. The rotor core is provided with a cooling hole 24d and a first air vent 24a that penetrate in the axial direction. The magnetic pole includes at least one magnet that circumferentially surrounds at least a portion of the cooling hole. The cap member has a first opposing surface 47 that faces the end face with a gap, and a hole 42 that penetrates the cap member in the axial direction. The hole axially overlaps with the end of one axial side of the first air vent. The first opposing surface axially overlaps with the end of one axial side of the cooling hole. The hole is connected to the gap.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a rotor, a rotating electric machine, and a drive device. [Background technology]

[0002] With the growing interest in hybrid vehicles and electric vehicles, various methods for cooling rotating electrical machines are being developed. For example, an internal fan is known that is placed at the end of the rotor core and cools the rotor core by sending air through holes provided in the rotor core (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-211862 Summary of the Invention [Problem to be solved by the invention]

[0004] In rotors with conventional structures, the cooling of the magnets was insufficient.

[0005] In view of the above circumstances, one object of the present invention is to provide a rotor, a rotating electric machine, and a drive unit that can efficiently cool a magnet. [Means for solving the problem]

[0006] One aspect of the rotor of the present invention is a rotor rotatable about a central axis, comprising: a plurality of magnets constituting a plurality of magnetic poles arranged circumferentially; a rotor core holding the magnets; and a cap member arranged opposite one axial end face of the rotor core. The rotor core is provided with a cooling hole and a first vent hole penetrating the rotor core in the axial direction. The magnetic pole has at least one magnet that circumferentially surrounds at least a portion of the cooling hole. The cap member has a first opposing surface facing the end face with a gap therebetween, and a hole penetrating the cap member in the axial direction. The hole axially overlaps with one axial end of the first vent hole. The first opposing surface axially overlaps with one axial end of the cooling hole. The hole is connected to the gap.

[0007] One aspect of a rotating electric machine of the present invention includes the rotor described above and a stator radially opposed to the rotor.

[0008] One aspect of a drive device of the present invention includes the above-described rotating electric machine and a power transmission unit that transmits power from the rotating electric machine. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to provide a rotor, a rotating electric machine, and a drive unit that can efficiently cool a magnet. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a conceptual diagram of a drive device according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a rotor according to one embodiment. [Figure 3] FIG. 3 is a perspective view of a fan (cap member) according to an embodiment. [Figure 4] FIG. 4 is a rear view of the fan (cap member) according to one embodiment. [Figure 5] FIG. 5 is a partially enlarged view of FIG. [Figure 6]FIG. 6 is a schematic diagram showing the air flow inside the first fan. [Figure 7] FIG. 7 is a schematic diagram showing the air flow inside the first fan. [Figure 8] FIG. 8 is a rear view of the fan (cap member) of the first modification. [Figure 9] FIG. 9 is a rear view of the fan (cap member) of the second modification. [Figure 10] FIG. 10 is a rear view of the fan (cap member) of the third modification. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment to which the present invention is applied will be described in detail with reference to the drawings. In the following description, the direction of gravity will be defined based on the positional relationship when the drive unit 100 is mounted on a vehicle positioned on a horizontal road surface. Unless otherwise specified in the following description, the direction parallel to the central axis J of the rotating electric machine 2 (Y-axis direction) will be simply referred to as the "axial direction," the radial direction centered on the central axis J will be simply referred to as the "radial direction," and the circumferential direction centered on the central axis J, i.e., around the axis of the central axis J, will be simply referred to as the "circumferential direction." However, the above "parallel direction" also includes a direction that is approximately parallel. The drive unit 100 of this embodiment will be described as being disposed so that the central axis J is parallel to the horizontal direction, but the orientation of the central axis J is not necessarily limited. In this specification, "facing in the axial direction" means facing in a direction parallel to the axial direction or in a direction having an axial component.

[0012] In each drawing, the circumferential direction θ around the central axis J is illustrated as necessary. In the following description, the direction in which the arrow indicating the circumferential direction θ in the drawing points is referred to as one circumferential side (+θ), and the opposite side is referred to as the other circumferential side (-θ).

[0013] <Drive unit> FIG. 1 is a conceptual diagram of a driving device 100 according to one embodiment. The drive device 100 of this embodiment is mounted on a vehicle powered by a rotating electric machine, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV), and is used as the power source thereof.

[0014] The driving device 100 includes a rotating electric machine 2, a power transmission unit 50, and a housing 6 that accommodates the rotating electric machine 2 and the power transmission unit 50. The driving device 100 may further include an inverter (not shown) that controls the rotating electric machine 2.

[0015] <Power transmission section> The power transmission unit 50 is connected to the rotor 20 and transmits the power of the rotating electric machine 2. The power transmission unit 50 has a first shaft 54, a second shaft 55, a first gear 51, a second gear 52, a third gear 53, and a differential device 56. The differential device 56 has a ring gear 56g and a pair of output shafts 57. Wheels (not shown) are connected to the pair of output shafts 57, respectively.

[0016] The first shaft 54 ​​extends in the axial direction around a central axis J. The first shaft 54 ​​is coupled to a rotor 20 of a rotating electric machine 2 (described later) and rotates together with the rotor 20. The first gear 51 is provided on the outer peripheral surface of the first shaft 54. The second shaft 55 rotates around an intermediate axis J2 that is parallel to the central axis J. The second gear 52 and the third gear 53 are provided on the outer peripheral surface of the second shaft 55. The second gear 52 meshes with the first gear 51. The third gear 53 meshes with a ring gear 56g of the differential device 56. When the vehicle turns, the differential device 56 transmits the torque transmitted from the third gear 53 to an output shaft 57 while absorbing the speed difference between the left and right wheels. The torque output from the rotating electric machine 2 is transmitted to the ring gear 56g of the differential device 56 via the first shaft 54, the first gear 51, the second gear 52, the second shaft 55 and the third gear 53, and is output to a pair of output shafts 57 via the differential mechanism part of the differential device 56.

[0017] <Rotating electric machines> The rotating electric machine 2 of this embodiment is an inner rotor type three-phase AC motor. The rotating electric machine 2 has both the function of outputting power as a motor and the function of generating electricity as a generator. The rotating electric machine 2 may be used as either a motor or a generator. Furthermore, the configuration of the rotating electric machine 2 is not limited to this embodiment, and may be, for example, a DC motor or a four- or more-phase AC motor. The rotating electric machine 2 includes a rotor 20 that can rotate around a central axis J, and a stator 30 that faces the rotor 20 in the radial direction.

[0018] <Stator> The stator 30 is held in the housing 6. The stator 30 surrounds the rotor 20 from the radially outer side. The stator 30 has a substantially annular stator core 32 centered on a central axis J, a coil 31 attached to the stator core 32, and an insulator (not shown) interposed between the stator core 32 and the coil 31.

[0019] The stator core 32 has a substantially annular core back portion 32a and a plurality of teeth 32b extending radially inward from the core back portion 32a. The core back portion 32a is held in the housing 6 by, for example, press fitting, shrink fitting, adhesive, or a fixing member such as a bolt. The plurality of teeth 32b are arranged in the circumferential direction. A coil wire is disposed between the circumferentially arranged teeth 32b. The coil wire positioned between adjacent teeth forms a coil 31. The coil 31 has a pair of coil ends 31a that protrude in the axial direction from both axial end faces of the stator core 32. The coil ends 31a are formed by bundling coil wires.

[0020] <Rotor> The rotor 20 has a shaft 21 extending in the axial direction around a central axis J, a rotor core 24 fixed to the outer peripheral surface of the shaft 21, a plurality of magnets 25 fixed to the rotor core 24, a pair of fans (cap members) 4, and a pair of fixing members 5. The shaft 21 is rotatable around the central axis J.

[0021] The rotor core 24 has a columnar shape extending in the axial direction. The rotor core 24 has end faces 24f on one axial side and the other axial side. That is, the rotor core 24 has a pair of end faces 24f. The end face 24f on one axial side of the rotor core 24 faces one axial side, and the end face 24f on the other axial side of the rotor core 24 faces the other axial side. A fan 4 is attached to each of the pair of end faces 24f. The rotor core 24 is made of a magnetic material. Although not shown in the drawings, in this embodiment, the rotor core 24 is configured by stacking multiple plate members in the axial direction. The multiple plate members may be stacked with their circumferential positions shifted one by one or every multiple plates. That is, the rotor core 24 may be skewed.

[0022] Fig. 2 is a cross-sectional view of the rotor 20 of this embodiment. Note that the shaft 21 is not shown in Fig. 2. As shown in Fig. 2, the rotor 20 is provided with a plurality of magnetic poles 20P. The rotor 20 of this embodiment is provided with eight magnetic poles 20P, including four north poles and four south poles. The north and south magnetic poles 20P are arranged alternately in the circumferential direction.

[0023] As shown in FIG. 2, the rotor 20 is assumed to have a plurality of first virtual lines Ld and a plurality of second virtual lines Lq. When viewed from the axial direction, the first virtual lines Ld pass through the d-axis of the rotor 20. The direction in which the first virtual lines Ld extend is the d-axis direction of the rotor 20. In other words, the direction in which the first virtual lines Ld extend is the main magnetic flux direction. On the other hand, the second virtual lines Lq pass through the q-axis of the rotor 20. The direction in which the second virtual lines Lq extend is the q-axis direction of the rotor 20. The direction in which the second virtual lines Lq extend is electrically perpendicular to the direction in which the first virtual lines Ld extend. The first virtual lines Ld and the second virtual lines Lq are alternately arranged along the circumferential direction. Although FIG. 2 illustrates only some of the first virtual lines Ld and some of the second virtual lines Lq, the rotor 20 is assumed to have the same number of first virtual lines Ld and second virtual lines Lq as the number of magnetic poles 20P.

[0024] Rotor core 24 is provided with a central hole 24c, multiple vent holes 24a and 24b, multiple magnet holes 24h, and multiple cooling holes 24d. Central hole 24c, vent holes 24a and 24b, magnet holes 24h, and cooling hole 24d extend axially and penetrate rotor core 24. Central hole 24c, vent holes 24a and 24b, magnet holes 24h, and cooling hole 24d open axially in each of a pair of end faces 24f of rotor core 24.

[0025] The central hole 24c extends in the axial direction with the central axis J as its center. In this embodiment, the central hole 24c has a substantially circular shape when viewed in the axial direction. The shaft 21 is inserted into the central hole 24c. The shaft 21 is fixed to the inner surface of the central hole 24c.

[0026] The multiple air vents 24a, 24b are arranged side by side in the circumferential direction. In this embodiment, the multiple air vents 24a, 24b are arranged at equal intervals in the circumferential direction. The air vents 24a, 24b are arranged on the second imaginary line Lq when viewed in the axial direction. The air vents 24a, 24b have a shape that convex radially outward when viewed in the axial direction. More specifically, the air vents 24a, 24b in this embodiment have a generally triangular shape with rounded corners that convex radially outward when viewed in the axial direction. The shape of the air vents 24a, 24b is not limited to this embodiment. When viewed in the axial direction, the shape of the air vents 24a, 24b may be, for example, a circle, an ellipse, a polygon, or a shape with at least a portion protruding in the circumferential or radial direction.

[0027] The multiple air holes 24a, 24b include first air holes 24a and second air holes 24b. That is, the rotor core 24 is provided with the first air holes 24a and the second air holes 24b. In this embodiment, the first air holes 24a and the second air holes 24b are arranged alternately in the circumferential direction. The rotor 20 of this embodiment is provided with four second air holes 24b and four first air holes 24a. In this embodiment, the second air holes 24b and the first air holes 24a have the same shape. The first air holes 24a and the second air holes 24b have different flow directions of air flowing therethrough. The second air holes 24b and the first air holes 24a may have different shapes.

[0028] The multiple magnet holes 24h are aligned in the circumferential direction. Magnets 25 are disposed inside the magnet holes 24h. The multiple magnet holes 24h include multiple first magnet holes 24p and multiple second magnet holes 24q. In this embodiment, the number of first magnet holes 24p is twice the number of second magnet holes 24q. A total of three magnets 25 disposed in two first magnet holes 24p and one second magnet hole 24q constitute one magnetic pole 20P. Here, a set of three magnet holes 24h accommodating the three magnets 25 that constitute one magnetic pole 20P is referred to as a hole group G. Furthermore, two first magnet holes 24p belonging to one hole group G are referred to as a hole pair P. In this embodiment, eight hole groups G are provided in the rotor core 24. Furthermore, one hole group G includes one hole pair P and one second magnet hole 24q. The two first magnet holes 24p of one hole pair P are adjacent to each other in the circumferential direction. That is, the rotor core 24 of this embodiment is provided with eight pairs of first magnet holes 24p that are adjacent to each other in the circumferential direction.

[0029] The two first magnet holes 24p of each hole pair P are arranged symmetrically with respect to the first imaginary line Ld when viewed in the axial direction. The first magnet hole 24p on one circumferential side (+θ side) of the first imaginary line Ld extends radially outward toward one circumferential side (+θ side). The first magnet hole 24p on the other circumferential side (-θ side) of the first imaginary line Ld extends radially outward toward the other circumferential side (-θ side). That is, the pair of first magnet holes 24p of each hole pair P are arranged spaced apart from each other in the circumferential direction and extend in directions that separate them circumferentially from the radially inner side to the radially outer side when viewed in the axial direction. The second magnet hole 24q is arranged between the radially outer ends of the pair of first magnet holes 24p belonging to the same hole group G and extends along the circumferential direction.

[0030] The multiple cooling holes 24d are aligned in the circumferential direction. The cooling holes 24d in this embodiment are arranged on a first imaginary line Ld. When viewed from the axial direction, the cooling holes 24d are surrounded by the three magnet holes 24h of the hole group G. The cooling holes 24d are located circumferentially between a pair of first magnet holes 24p that make up the hole pair P. The cooling holes 24d in this embodiment are elongated holes that extend linearly in a direction perpendicular to the radial direction when viewed from the axial direction. However, the shape of the cooling holes 24d is not limited to this embodiment.

[0031] (magnet) The multiple magnets 25 form multiple magnetic poles 20P arranged in the circumferential direction. One magnet 25 is disposed in each magnet hole 24h. In this embodiment, the magnet 25 is fixed to the inner surface of the magnet hole 24h by a fixing means such as an adhesive. This allows the rotor core 24 to hold the magnet 25. The magnet 25 may also be fixed in the magnet hole 24h by a fixing means such as crimping or press fitting. The type of magnet 25 is not particularly limited. The magnet 25 may be, for example, a neodymium magnet or a ferrite magnet. In this embodiment, the magnet 25 has a rectangular parallelepiped shape that is elongated in the axial direction. Therefore, the magnet 25 of this embodiment has a rectangular shape when viewed axially. More specifically, the magnet 25 of this embodiment has a substantially rectangular shape when viewed axially. The magnet 25 extends, for example, from one axial end to the other axial end of the rotor core 24. The axial dimension of the magnet 25 may be shorter than the axial dimension of the rotor core 24 (the axial dimension of the magnet hole 24h). Furthermore, the shape of magnet 25 is not limited to that described above. Magnet 25 placed in one second magnet hole 24q may be made up of multiple magnets. Magnet 25 placed in first magnet hole 24p may be made up of multiple magnets. The type of magnet placed in second magnet hole 24q may be different from the type of magnet placed in first magnet hole 24p.

[0032] In the following description, the magnet 25 placed in the first magnet hole 24p will be referred to as the first magnet 25p, and the magnet 25 placed in the second magnet hole 24q will be referred to as the second magnet 25q. The magnetic pole 20P includes two first magnets 25p and one second magnet 25q, for a total of three magnets 25. In this embodiment, the number of first magnets 25p is twice the number of second magnets 25q.

[0033] The second magnet 25q is disposed such that its longitudinal direction is perpendicular to the first imaginary line Ld when viewed from the axial direction. The two first magnets 25p belonging to one magnetic pole 20P are disposed radially inward of the second magnet 25q and circumferentially symmetrical with respect to the first imaginary line Ld. Furthermore, in one magnetic pole 20P, the two first magnets 25p are spaced apart radially outward. The magnetization direction of each of the first magnet 25p and the second magnet 25q is the thickness direction. The two first magnets 25p and one second magnet 25q constituting one magnetic pole 20P each face the same polarity radially outward. For example, if the surface of the second magnet 25q facing radially outward is an N pole (or an S pole), the surfaces of the two first magnet holes 24p facing radially outward are also N poles (or S poles).

[0034] <Fan (cap component)> As shown in FIG. 1, the fan 4 is attached to end faces 24f on one and the other axial sides of the rotor core 24. The fan 4 is disposed axially between the rotor core 24 and the fixed member 5. The fixed member 5 is a substantially annular member, and is press-fitted onto the outer peripheral surface of the shaft 21. This fixes the fixed member 5 to the shaft 21. Furthermore, by sandwiching the fan 4 between the fixed member 5 and the rotor core 24, the fixed member 5 prevents the fan 4 from coming off the shaft 21 in the axial direction.

[0035] The pair of fans 4 rotate around the central axis J together with the rotor core 24. Each fan 4 is located radially inward of the coil end 31a on one axial side and the other axial side. In this embodiment, the pair of fans 4 have the same shape. As will be described later, the pair of fans 4 are attached to the rotor core 24 at different angles around the central axis J.

[0036] The fan 4 of this embodiment is made of an aluminum alloy and is formed by, for example, aluminum die-casting. The fan 4 may be made of a resin material or other metal material. The fan 4 may be formed not only by casting such as aluminum die-casting, but also by machining such as cutting or pressing, or by other methods.

[0037] The fan 4 of this embodiment covers the end face 24f of the rotor core 24. The fan 4 covers the multiple magnet holes 24h of the rotor core 24. This makes it possible to prevent the magnets 25 from coming off the magnet holes 24h. That is, according to this embodiment, there is no need to provide a separate member, such as a plate, between the fan 4 and the rotor core 24 to cover the openings of the magnet holes 24h, reducing the number of parts and allowing the rotor 20 to be manufactured at low cost.

[0038] The fan 4 is provided with a plurality of inlet channels 45 and a plurality of outlet channels 46. The plurality of inlet channels 45 and the plurality of outlet channels 46 are each connected to one of the plurality of vent holes 24a, 24b. Here, of the pair of fans 4, one located on the +Y side of the rotor core 24 is referred to as the first fan 4A, and the other located on the -Y side of the rotor core 24 is referred to as the second fan 4B. The first fan 4A and the second fan 4B are attached to the rotor core 24 at different angles around the central axis J. The inlet channel 45 of the first fan 4A is connected to the first vent hole 24a, and the outlet channel 46 of the first fan 4A is connected to the second vent hole 24b. Meanwhile, the inlet channel 45 of the second fan 4B is connected to the second vent hole 24b, and the outlet channel 46 of the first fan 4A is connected to the first vent hole 24a. That is, the first ventilation hole 24a and the second ventilation hole 24b each connect the inflow path 45 of one fan 4 of the pair of fans 4 to the outflow path 46 of the other fan 4.

[0039] The outflow passage 46 extends radially and opens radially outward. When the rotor 20 rotates, centrifugal force is applied to the air inside the outflow passage 46 due to the rotation about the central axis J of the fan 4. As a result, the air inside the outflow passage 46 flows radially outward. As air flows from the outflow passage 46, negative pressure is generated inside the air vents 24a, 24b connected to the outflow passage 46. As a result, air flows into the air vents 24a, 24b via the inflow passage 45. An air flow along the axial direction is formed in the air vents 24a, 24b.

[0040] According to this embodiment, air flows axially through the air holes 24a and 24b, allowing the rotor 20 to be cooled by the air flowing inside. Furthermore, according to this embodiment, the air inside the second air holes 24b flows from the other axial side to the one axial side, and the air inside the first air holes 24a flows from the one axial side to the other axial side. That is, the direction of the air flowing in the axial direction through the second air holes 24b is opposite to the direction of the air flowing inside the first air holes 24a. Therefore, in the rotor 20, the reaction force of the air resistance acting on the inner surface of the second air holes 24b and the reaction force of the air resistance acting on the inner surface of the first air holes 24a cancel each other out. According to this embodiment, it is possible to prevent the reaction force of the air resistance from being applied unevenly to the rotor 20, thereby preventing the rotational balance of the rotor 20 from being deteriorated.

[0041] FIG. 3 is a perspective view of the fan 4, and FIG. 4 is a rear view of the fan 4. As shown in FIG. The first fan 4A and the second fan 4B have the same configuration except for the different orientations at which they are attached to the rotor core 24. In the following explanation, the position and shape of each part of the pair of fans 4 will be explained based on the orientation of the first fan 4A with respect to the Y axis. In the following explanation of the fans 4, the direction in which the end face 24f of the rotor core 24 faces will be referred to as one axial side (+Y side), and the opposite direction will be referred to as the other axial side (-Y side).

[0042] As shown in FIG. 3, the fan 4 includes a main body 40 and a rib 40d. The main body 40 is plate-shaped and extends perpendicular to the axial direction. When viewed from the axial direction, the main body 40 is substantially circular and centered on the central axis J. The main body 40 includes a first surface 40a facing the other axial side (-Y side), a second surface 40b facing the one axial side (+Y side), and an outer surface 40c facing radially outward. That is, the fan 4 includes the first surface 40a, the second surface 40b, and the outer surface 40c. The first surface 40a and the second surface 40b each extend along a plane perpendicular to the axial direction. The first surface 40a faces the end surface 24f of the rotor core 24. The second surface 40b is located on the opposite side of the first surface 40a in the axial direction. The outer surface 40c is connected to the first surface 40a and the second surface 40b.

[0043] The rib 40d protrudes from the second surface 40b of the main body 40 to one axial side (+Y side). The rib 40d extends circumferentially about the central axis J. The rib 40d has a substantially annular shape centered on the central axis J. The rib 40d is arranged on the second surface 40b side along the radially outer edge of the opening of the hole 42. The provision of the rib 40d increases the distance between the opening of the inlet channel 45 on one axial side (+Y side) and the opening 43c of the outlet channel 46. This prevents air flowing out from the opening 43c of the outlet channel 46 from directly flowing into the inlet channel 45.

[0044] The ribs 40d can be used, for example, as cutting allowances used to adjust the balance of the fan 4. If the center of gravity of the rotor 20 after assembly is misaligned with the central axis J, the balance of the rotor 20 can be corrected by cutting a portion of the ribs 40d in the circumferential direction. Methods for cutting the ribs 40d include, for example, machining the surfaces of the ribs 40d facing radially outward by drilling, but are not particularly limited to this method. The shape of the ribs 40d is not limited to this embodiment. The fan 4 does not necessarily have to have the ribs 40d.

[0045] The main body 40 is provided with a shaft insertion hole 40h, a plurality of holes 42, a plurality of first recesses 43, and a plurality of second recesses 44. That is, the fan 4 has the shaft insertion hole 40h, a plurality of holes 42, a plurality of first recesses 43, and a plurality of second recesses 44. The shaft insertion hole 40h and the holes 42 pass through the fan 4 in the axial direction.

[0046] When viewed in the axial direction, the shaft insertion hole 40h has a circular shape centered on the central axis J. The shaft 21 is inserted into the shaft insertion hole 40h. In this embodiment, the inner diameter of the shaft insertion hole 40h is slightly larger than the outer diameter of the shaft 21.

[0047] As shown in FIG. 4, four holes 42 are provided in the fan 4 in this embodiment. The holes 42 are arranged in the circumferential direction. The holes 42 in this embodiment are arranged at equal intervals in the circumferential direction. The holes 42 axially overlap with the ends of the first air vents 24a on one axial side (+Y). The holes 42 guide air to the first air vents 24a. In other words, the holes 42 form an inflow path 45. The holes 42 may overlap entirely or only partially with the first air vents 24a when viewed in the axial direction.

[0048] The opening of the hole 42 in the first surface 40a has a generally triangular shape with rounded corners that protrudes radially outward when viewed in the axial direction. In this embodiment, the shape of the opening of the hole 42 in the first surface 40a is generally the same as the shape of the opening of the end surface 24f of the air vents 24a, 24b. However, the shape of the opening of the hole 42 is not limited thereto. The shape of the opening of the hole 42 in the first surface 40a may be different from the shape of the opening of the end surface 24f of the air vents 24a, 24b. The shape of the opening of the hole 42 in the first surface 40a may be the same as either the air vent 24a or the air vent 24b, or may be different from the other.

[0049] 5 is a partially enlarged view of FIG. 4. In this embodiment, the first surface 40a includes a first opposing surface 47, a second opposing surface 48, and a third opposing surface 49. That is, the fan 4 has the first opposing surface 47, the second opposing surface 48, and the third opposing surface 49. The first opposing surface 47, the second opposing surface 48, and the third opposing surface 49 are surfaces that respectively face the end surface 24f of the rotor core 24 in the axial direction.

[0050] The first opposing surface 47 faces the end surface 24f of the rotor core 24 with a first gap (gap) G1 between them. Similarly, the third opposing surface 49 faces the end surface 24f of the rotor core 24 with a second gap G2 between them. The second opposing surface 48 is located on the other axial side (-Y) of the first opposing surface 47 and the third opposing surface 49. The second opposing surface 48 contacts the end surface 24f of the rotor core 24. In this embodiment, the first opposing surface 47 and the third opposing surface 49 are arranged on the same plane. However, the first opposing surface 47 and the third opposing surface 49 may be misaligned in the axial direction as long as they are located on one axial side (+Y) of the second opposing surface 48.

[0051] In this embodiment, a first recess 43 and a second recess 44 are provided in the second opposing surface 48. The first recess 43 and the second recess 44 are each recessed toward one axial side (+Y) with respect to the second opposing surface 48. The bottom surface of the first recess 43 is the third opposing surface 49. The bottom surface of the second recess 44 is the first opposing surface 47.

[0052] 4, in this embodiment, the fan 4 is provided with a plurality of (four in this embodiment) first recesses 43. In this embodiment, the plurality of first recesses 43 are arranged at equal intervals in the circumferential direction. Furthermore, each first recess 43 is disposed between two holes 42 arranged in the circumferential direction. In other words, the holes 42 and the first recesses 43 are arranged alternately in the circumferential direction.

[0053] The first recess 43 has a connecting portion 43a, a groove portion 43b extending radially outward from the connecting portion 43a, and an opening portion 43c opening to the outer surface 40c. The connecting portion 43a axially overlaps with an end portion on one axial side (+Y) of the second air vent 24b. In this embodiment, the connecting portion 43a has a generally triangular shape with rounded corners that protrudes radially outward when viewed from the axial direction. The shape of the connecting portion 43a when viewed from the axial direction is generally the same as the shape of the openings on the end faces 24f of the air vents 24a, 24b. The groove portion 43b connects to the radially outer end portion of the connecting portion 43a. The groove portion 43b faces the end face 24f of the rotor core 24 in the axial direction. The radially inner end portion of the groove portion 43b connects to the connecting portion 43a. The radially outer end portion of the groove portion 43b forms the opening portion 43c.

[0054] The first recess 43 of this embodiment is recessed toward one axial side (+Y side) with respect to the second opposing surface 48 with a uniform depth throughout. However, the depth of the first recess 43 does not necessarily have to be uniform. The space surrounded by the first recess 43 and the end surface 24f of the rotor core 24 functions as a part of the outflow channel 46 that guides air in the second air vent 24b radially outward. That is, at least a part of the outflow channel 46 is provided in the space surrounded by the end surface 24f of the rotor core 24 and the first recess 43. In this embodiment, the upstream region of the outflow channel 46 is provided inside the connecting portion 43a, and the downstream region is provided inside the groove portion 43b. The first recess 43 extends along the radial direction and opens at the outer surface 40c. That is, the outflow channel 46 extends in the radial direction. Therefore, the flow path cross-sectional area of ​​the outflow channel 46 of this embodiment can be defined as the cross-sectional area of ​​the first recess 43 in a cross section perpendicular to the radial direction.

[0055] According to this embodiment, the first recess 43 axially overlaps with the end of one axial side (+Y) of the second air vent 24b and opens radially outward at the outer surface 40c. According to this embodiment, the air inside the first recess 43 flows radially outward from the outer surface 40c due to centrifugal force caused by the rotation of the rotor 20. This makes it possible to create a negative pressure inside the first recess 43, and to form an air flow inside the second air vent 24b toward the first recess 43. This makes it possible to cool the rotor core 24 by the air inside the second air vent 24b.

[0056] As shown in Fig. 3, in this embodiment, the opening 43c of the first recess 43 has a substantially rectangular shape when viewed from the radial direction. The opening 43c faces radially outward. When the rotor 20 rotates, the opening 43c functions as an outlet for discharging air from the outlet passage 46. The opening 43c faces the coil end 31a in the radial direction. When the rotor 20 rotates, the air flowing from the opening 43c hits the coil end 31a and can cool the coil end 31a.

[0057] As shown in FIG. 4 , the circumferential dimension of the connecting portion 43a gradually decreases radially outward. Therefore, the flow path cross-sectional area of ​​the outflow channel 46 gradually decreases in the region provided within the connecting portion 43a. Meanwhile, the groove portion 43b of this embodiment extends to the opening 43c with a uniform width and depth over its entire length. Therefore, the flow path cross-sectional area of ​​the outflow channel 46 is substantially constant from the radially inner end of the groove portion 43b to the opening 43c. The flow path cross-sectional area of ​​the outflow channel 46 is smaller downstream than upstream. Therefore, the flow path cross-sectional area of ​​the outflow channel 46 is smallest at the opening 43c. According to this embodiment, the flow velocity of the air flowing through the outflow channel 46 can be maximized at the opening 43c. This increases the flow velocity of the air flowing from the outflow channel 46 toward the coil end 31a via the opening 43c, thereby efficiently cooling the coil end 31a.

[0058] In the outlet channel 46 of this embodiment, the cross-sectional area of ​​the flow path continuously decreases radially outward at the connecting portion 43a. This embodiment reduces pressure loss compared to when the cross-sectional area of ​​the flow path is suddenly reduced. As a result, the flow velocity of the air flowing from the outlet channel 46 to the coil end 31a through the opening 43c can be increased, allowing the coil end 31a to be cooled efficiently.

[0059] The first recesses 43 of this embodiment extend radially outward from the second air vent 24b toward the outer surface 40c and axially overlap the second imaginary line Lq of the rotor 20. According to this embodiment, multiple first recesses 43 can be arranged between multiple magnet holes 24h that are lined up in the circumferential direction. Furthermore, by arranging the grooves 43b of the first recesses 43 in a groove shape along the second imaginary line Lq, the grooves 43b can be made linear, and the grooves 43b can be arranged to avoid the magnet holes 24h while reducing the pressure loss of the air inside the grooves 43b.

[0060] The arrangement and shape of the first recess 43 in this embodiment are merely an example, and various other configurations may be adopted. For example, a portion of the first recess 43 may be disposed on the first virtual line Ld, or may be disposed between the first virtual line Ld and the second virtual line Lq.

[0061] In this embodiment, the fan 4 is provided with eight second recesses 44. The multiple second recesses 44 are arranged side by side in the circumferential direction. The second recesses 44 are arranged between the holes 42 and the first recesses 43 in the circumferential direction. The second recesses 44 in this embodiment are recessed to one axial side (+Y side) with a uniform depth throughout with respect to the second opposing surface 48. However, the depth of the second recesses 44 does not necessarily have to be uniform.

[0062] As shown in Fig. 5, the second recess 44 overlaps with the opening of the end of the cooling hole 24d on one axial side (+Y) when viewed from the axial direction. Therefore, the first opposing surface 47 overlaps with the end of the cooling hole 24d on one axial side (+Y). The first opposing surface 47 is surrounded by a wall portion 80. The wall portion 80 protrudes from the first opposing surface 47 to the other axial side (-Y). The tip surface of the wall portion 80 on the other axial side (-Y) is the second opposing surface 48. The second recess 44 is formed by the wall portion 80 surrounding the first opposing surface 47.

[0063] In this embodiment, the multiple second recesses 44 are classified into one-side recesses 44A located on one circumferential side of one hole 42 and other-side recesses 44B located on the other circumferential side (-θ) of one hole 42. The one-side recesses 44A and the other-side recesses 44B are arranged circumferentially symmetrically with respect to one hole 42. In the following description of the wall portion 80, the wall portion 80 of the one-side recess 44A will be described. The wall portion 80 of the other-side recess 44B has a shape circumferentially symmetrical to the wall portion 80 constituting the one-side recess 44A, so its description will be omitted here. Note that in FIG. 5, the wall portion 80 constituting the one-side recess 44A is emphasized by adding a dotted pattern.

[0064] The wall portion 80 includes a first wall portion 81, a second wall portion 82, a third wall portion 83, and a fourth wall portion 84. That is, the first wall portion 81, the second wall portion 82, the third wall portion 83, and the fourth wall portion 84 each protrude from the first opposing surface 47 toward the other axial side (-Y). When viewed from the axial direction, the first wall portion 81 and the fourth wall portion 84 are located on the other circumferential side (-θ) of the first opposing surface 47 of the one-side recess 44A. When viewed from the axial direction, the third wall portion 83 is located on one circumferential side (+θ) of the first opposing surface 47 of the one-side recess 44A. When viewed from the axial direction, the second wall portion 82 is located radially outward of the first opposing surface 47 of the one-side recess 44A.

[0065] The first wall portion 81 is located between the first opposing surface 47 and the hole 42 as viewed in the axial direction. That is, the first wall portion 81 is provided between the hole 42 and the first gap G1 as viewed in the axial direction. As a result, the first wall portion 81 separates the hole 42 from the first gap G1. The first wall portion 81 extends along a portion of the outer shape of the hole 42 as viewed in the axial direction. In this embodiment, the second wall portion 82 of the one-side recess 44A extends in a direction inclined toward the other circumferential side (-θ) as it extends radially outward. Furthermore, the second wall portion 82 of the other-side recess 44B extends in a direction inclined toward one circumferential side (+θ) as it extends radially outward. The radially outer end of the first wall portion 81 of the one-side recess 44A and the radially outer end of the first wall portion 81 of the other-side recess 44B are connected to each other radially outside the hole 42.

[0066] In this embodiment, the first wall portion 81 is provided with a first communication portion 81a that connects the hole portion 42 and the first gap G1. The first communication portion 81a in this embodiment is a groove that is recessed from the tip surface (second opposing surface 48) of the first wall portion 81 toward one axial side (+Y). The bottom surface of the first communication portion 81a (the surface facing the other axial side (-Y)) is disposed on the same plane as the first opposing surface 47. When viewed from the axial direction, the first communication portion 81a extends in a direction perpendicular to the extension direction of the first wall portion 81.

[0067] A first communication portion 81a is provided in each of the first wall portions 81 arranged on one circumferential side (+θ) and the other circumferential side (-θ) of one hole 42. Therefore, one hole 42 is connected to the one-side recess 44A and the other-side recess 44B via each of the first communication portions 81a.

[0068] The fourth wall portion 84 is located radially outward from the hole 42. The fourth wall portion 84 extends linearly radially outward from the connection between the first wall portions 81, which are located on one circumferential side (+θ) and the other circumferential side (-θ) of one hole 42. The fourth wall portion 84 is located between the first opposing surface 47 of the one-side recess 44A and the first opposing surface 47 of the other-side recess 44B. Therefore, the fourth wall portion 84 defines two first gaps G1. A radially outer end of the fourth wall portion 84 is connected to the outer surface 40c of the fan 4.

[0069] The third wall portion 83 is located between the first opposing surface 47 and the first recessed portion 43 when viewed in the axial direction. That is, the third wall portion 83 is provided between the first recessed portion 43 and the first gap G1 when viewed in the axial direction. As a result, the third wall portion 83 separates the first gap G1 from the second gap G2. The third wall portion 83 extends in the radial direction along part of the outer shape of the first recessed portion 43. A radially inner end of the third wall portion 83 is connected to a radially inner end of the first wall portion 81. A radially outer end of the third wall portion 83 is connected to the outer surface 40c of the fan 4.

[0070] The second wall portion 82 is located radially outward of the first gap G1 as viewed from the axial direction. In this embodiment, the second wall portion 82 extends along the circumferential direction. That is, the second wall portion 82 extends along a direction perpendicular to the radial direction. In this embodiment, the second wall portion 82 extends in an arc shape centered on the central axis J. However, the second wall portion 82 may also extend linearly in a direction perpendicular to the radial direction. As viewed from the axial direction, the second wall portion 82 is aligned on a straight line with the first air vent 24a and the cooling hole 24d. The second wall portion 82 is provided between the first gap G1 and the outside E of the fan 4. As a result, the second wall portion 82 separates the first gap G1 from the outside E of the fan 4.

[0071] In this specification, the interior of the fan 4 refers to the space located radially inward from the outer edge of the fan 4 and surrounded by multiple wall surfaces of the fan 4. Additionally, the exterior E of the fan 4 refers to the space radially outward from the outer edge of the fan 4 when viewed in the axial direction.

[0072] The second wall portion 82 extends in the circumferential direction between a radially outer end of the third wall portion 83 and a radially outer end of the fourth wall portion 84. In the present embodiment, a second communication portion 82a is provided in the second wall portion 82. The second communication portion 82a is provided by partially discontinuing the second wall portion 82. The second communication portion 82a connects the first gap G1 with the outside E of the fan 4. The second communication portion 82a is provided at an end of the second wall portion 82 on the other circumferential side (-θ). The second wall portion 82 is not connected to the fourth wall portion 84 due to the provision of the second communication portion 82a.

[0073] 6 and 7 are schematic diagrams showing the airflow inside the first fan 4A. In FIGS. 6 and 7, the first fan 4A rotates around a central axis J in the direction indicated by the arrow in the figure, which indicates the direction of rotation R. In the following description, the direction indicated by the arrow in the figure, which indicates the direction of rotation R, will be referred to as the forward rotation direction (+R), and the opposite side will be referred to as the backward rotation direction (-R). In the example shown in FIG. 6, the rotation direction R of the fan 4 is toward the other circumferential side (-θ).

[0074] As shown in FIG. 6, when the first fan 4A rotates around the central axis J in the forward direction of rotation (+R), the holes 42 function as inflow channels 45. That is, the holes 42 draw air from one axial side (+Y) of the fan 4 and send air F1 toward the other axial side (-Y) to the first air vents 24a of the rotor core 24. Furthermore, the pressure of the air F1 passing through the holes 42 increases in the rearward direction of rotation (-R) within the holes 42 due to the inertial force applied when the fan 4 rotates. As a result, a portion of the air F1 passing through the holes 42, air F2, flows into the first communication portion 81a extending rearward in the direction of rotation (-R) relative to the holes 42.

[0075] The air F2 passing through the first communication portion 81a flows into the first gap G1 inside the one-side recess 44A. This increases the pressure in the first gap G1, which is located rearward (-R) in the rotational direction from the hole portion 42. In response to the increase in pressure, a portion of the air F3 in the first gap G1 flows into the cooling hole 24d that opens into the first gap G1. This forms a flow of air F3 in the cooling hole 24d that flows toward the other axial side (-Y).

[0076] As shown in FIG. 6, inside the cooling hole 24d adjacent to the first air hole 24a on the rear (-R) side in the rotational direction, air F3 flows in the same direction as the first air hole 24a (i.e., on the other axial side (-Y)). That is, inside the cooling hole 24d adjacent to one of the air holes 24a, 24b on the rear (-R) side in the rotational direction, air flows in the same direction as the air hole 24a, 24b. While FIG. 6 shows the flows of air F1, F2, and F3 inside the first fan 4A, a similar air flow is also generated inside the second fan 4B (see FIG. 1) located on the other axial side (-Y) of the rotor core 24. Therefore, as shown in FIG. 7, inside the cooling hole 24d adjacent to the second air hole 24b on the rear (-R) side in the rotational direction, air flows in the same direction as the second air hole 24b. Since the air F4 inside the second ventilation hole 24b flows toward one axial side (+Y), a flow of air F5 toward one axial side (+Y) also occurs inside the cooling hole 24d adjacent to the second ventilation hole 24b and rearward (-R) in the rotational direction.

[0077] As shown in Figure 7, air F5 flowing through cooling hole 24d toward one axial side (+Y) reaches one axial side (+Y) of rotor core 24 and flows into other-side recess 44B. Centrifugal force accompanying the rotation of rotor 20 is applied to air F5 flowing out into first gap G1. As a result, air F5 flowing out into first gap G1 flows radially outward and flows out through second communication portion 82a to outside E of first fan 4A. Such an air flow is also formed inside second fan 4B.

[0078] As described above, when the rotation direction R of the rotor 20 is toward the other circumferential side (-θ), the one-side recess 44A functions as an inlet path for sending air from the holes 42 to the cooling holes 24d, and the other-side recess 44B functions as an outlet path for discharging air from the cooling holes 24d. In contrast, when the rotation direction R of the rotor 20 is toward one circumferential side (+θ), the functions of the one-side recess 44A and the other-side recess 44B are reversed, with the one-side recess 44A functioning as an outlet path and the other-side recess 44B functioning as an inlet path.

[0079] The fan 4 of this embodiment has a hole 42 connected to the first air vent 24a and a first opposing surface 47 facing the end face 24f with a first gap G1 between them. The first opposing surface 47 axially overlaps with an end of the cooling hole 24d on one axial side (+Y). Therefore, the cooling hole 24d is connected to the first gap G1. The hole 42 is also connected to the first gap G1 via the first communication portion 81a. That is, according to this embodiment, the hole 42 can be connected to the cooling hole 24d via the first gap G1. According to this embodiment, a portion of the air flowing from the hole 42 to the first air vent 24a can flow into the first gap G1 and be guided to the cooling hole 24d. This allows air to pass through the cooling hole 24d, cooling the rotor core 24.

[0080] The magnets 25 that make up the magnetic poles 20P generate heat due to the influence of eddy currents that occur when the rotor 20 rotates. When the temperature of the magnets 25 exceeds a certain level due to heat generation, the magnetic force of the magnets 25 may weaken. Furthermore, the rotor core 24 that holds the magnets 25 generates heat due to the magnetic flux generated between the magnets 25 and the stator 30, causing the temperature to rise. If the temperature of the rotor core 24 rises, this may adversely affect the formation of a magnetic path inside the rotor core 24. Therefore, in the rotor 20, it is necessary to suppress the temperature rise of the magnets 25 and the rotor core 24 around the magnets 25.

[0081] As shown in FIG. 2, cooling hole 24d in this embodiment is located circumferentially between two first magnets 25p that are aligned in the circumferential direction and are among the multiple magnets 25 that make up one magnetic pole 20P. According to this embodiment, the two first magnets 25p can be cooled by air F3 and F5 flowing through cooling hole 24d. Furthermore, according to this embodiment, second magnet 25q is disposed radially outside cooling hole 24d. In other words, cooling hole 24d is surrounded by three magnets 25 when viewed from the axial direction. According to this embodiment, the multiple magnets 25 that make up magnetic pole 20P can be cooled by air F3 and F5 flowing through cooling hole 24d.

[0082] In this embodiment, one magnetic pole 20P is composed of three magnets 25. The three magnets 25 constituting the magnetic pole 20P are arranged in three magnet holes 24h of a hole group G that are arranged in a substantially triangular shape when viewed from the axial direction. However, the number of magnets constituting one magnetic pole is not limited to this embodiment. As an example, one magnetic pole may be composed of only the two first magnets 25p described above and may not include a second magnet 25q. As another example, one magnetic pole may have four first magnets 25p, with two pairs of first magnets 25p arranged so as to overlap radially when viewed from the axial direction. Furthermore, in this embodiment, the magnetic pole 20P is composed of multiple magnets 25. However, it is sufficient for the magnetic pole 20P to include at least one magnet 25. Even in this case, the cooling effect of the cooling hole 24d can be obtained when the cooling hole 24d is circumferentially surrounded by at least one magnet 25 constituting one magnetic pole 20P. That is, magnetic pole 20P may have at least one magnet 25 that circumferentially surrounds at least a portion of cooling hole 24d. An example of one magnet 25 surrounding cooling hole 24d circumferentially is a case where a cooling hole is disposed between both circumferential ends of a U-shaped magnet that opens radially outward when viewed axially.

[0083] As shown in FIG. 6 , when the rotation direction R of the rotor 20 is set to the other circumferential side (−θ), the air F1 flowing through the holes 42 tends to flow into the first gap G1 located on one circumferential side (+θ) with respect to the holes 42 due to the inertial force applied to the air F1 during rotation. According to this embodiment, by opening the cooling holes 24d to the first gap G1 located on one circumferential side (+θ) with respect to the holes 42, it becomes possible to guide air from the holes 42 to the cooling holes 24d through the first gap G1 when the rotor 20 is rotated to the other circumferential side (−θ). This allows air F3 to flow into the cooling holes 24d, and the rotor core 24 can be cooled using the cooling holes 24d. Similarly, by opening the cooling holes 24d to the first gap G1 located on the other circumferential side (−θ) with respect to the holes 42, it becomes possible to guide air from the holes 42 to the cooling holes 24d through the first gap G1 when the rotor 20 is rotated to the one circumferential side (+θ).

[0084] In the present embodiment, a first wall portion 81 is provided between the hole portion 42 and the first gap G1. The first wall portion 81 also has a first communication portion 81a that connects the hole portion 42 and the first gap G1. According to the present embodiment, the flow of air F2 from the hole portion 42 to the first gap G1 is restricted by the first communication portion 81a. This increases the flow velocity of the air F2 flowing through the first communication portion 81a, allowing high-velocity air F3 to flow through the cooling holes 24d. As a result, the rotor core 24 and the magnets 25 can be efficiently cooled by the air F3 flowing through the cooling holes 24d. Furthermore, the provision of the first wall portion 81 restricts the flow rate of air flowing from the hole portion 42 toward the first gap G1, thereby preventing the flow rate of air F1 flowing from the hole portion 42 into the first air holes 24a from being excessively reduced.

[0085] In the present embodiment, the first communicating portion 81a is recessed toward one axial side (+Y) and has a groove shape extending in a direction perpendicular to the direction in which the first wall portion 81 extends. However, the configuration of the first communicating portion 81a is not limited to this embodiment. The first communicating portion 81a may have a notch shape extending circumferentially from the outer edge of the hole portion 42, or may be a hole extending radially. The notch-shaped first communicating portion will be described later in Modification Example 1.

[0086] In this embodiment, the first communication portion 81a extends radially outward from the hole 42 toward the first gap G1. A centrifugal force acting radially outward is applied to the air in the first communication portion 81a as the rotor 20 rotates. According to this embodiment, the centrifugal force can smoothly guide the air in the first communication portion 81a to the first gap G1.

[0087] As shown in FIG. 5, when viewed from the axial direction, imagine an imaginary line VL that overlaps with the first communication portion 81a and extends in the same direction as the first communication portion 81a. In this embodiment, the cooling hole 24d is located on the imaginary line VL when viewed from the axial direction. The air F2 that flows from the hole portion 42 into the first gap G1 via the first communication portion 81a flows along the imaginary line VL. According to this embodiment, by locating the cooling hole 24d on the imaginary line VL when viewed from the axial direction, the air that flows from the first communication portion 81a into the first gap G1 can be efficiently guided to the cooling hole 24d.

[0088] As shown in FIG. 6, the fan 4 of this embodiment has a second wall portion 82 located radially outward of the first gap G1 and extending in a direction perpendicular to the radial direction. When viewed from the axial direction, the second wall portion 82 is aligned with the first air vent 24a and the cooling holes 24d. The second wall portion 82 is positioned opposite the flow of air F2 that flows from the first air vent 24a into the first gap G1 and is guided to the cooling holes 24d. Therefore, when the first gap G1 is used as an inflow path, the air F2 that flows into the first gap G1 is prevented from being discharged to the outside E of the fan 4, and more air F2 can be guided to the cooling holes 24d.

[0089] 5, the second wall portion 82 of this embodiment is disposed on an imaginary line VL that extends along the first communication portion 81a. According to this embodiment, the air F2 that flows from the hole portion 42 into the first gap G1 via the first communication portion 81a can be blocked by the second wall portion 82. This allows the air to remain on the radially inner side of the second wall portion 82 and to be efficiently guided to the cooling hole 24d.

[0090] 7, the second wall portion 82 is provided with a second communication portion 82a that connects the first gap G1 with the outside E of the fan 4. According to the present embodiment, when the first gap G1 serves as a discharge path, the air F5 that flows from the cooling holes 24d into the first gap G1 can be discharged to the outside E of the fan 4 via the second communication portion 82a. This makes it possible to prevent the flow of the air F5 discharged from the cooling holes 24d from stagnating.

[0091] In this embodiment, the fan 4 has a third wall portion 83 provided between the first recess 43 and the first gap G1 when viewed in the axial direction. Air that has passed through the second air vents 24b and been heated by the rotor core 24 flows inside the first recess 43. Therefore, if some of the air passing through the first recess 43 flows into the cooling holes 24d, the temperature of the air flowing through the cooling holes 24d may increase, potentially preventing efficient cooling of the rotor core 24 and the magnets 25 using the cooling holes 24d. According to this embodiment, the provision of the third wall portion 83 prevents the air passing through the first recess 43 from flowing into the first gap G1. This also prevents the heated air from flowing into the cooling holes 24d, allowing efficient cooling of the rotor core 24 and the magnets 25.

[0092] According to the rotor 20 of this embodiment, a fan 4 is disposed on each of the end faces 24f of the rotor core 24. According to this embodiment, the inlet passages 45 and outlet passages 46 of each fan 4 can be disposed at both axial ends of the air vents 24a, 24b, allowing air flowing through the rotor 20 to smoothly flow toward the coil ends 31a. Furthermore, according to this embodiment, the fans 4 disposed at both ends of the rotor 20 are formed to have the same shape, eliminating the need to separately manufacture fans 4 with different shapes, thereby reducing the number of components used in the rotor 20. Note that the fan 4 may be disposed facing at least one of the end faces 24f on one axial side or the other axial side of the rotor core 24. When the fan 4 is disposed on the end face 24f on one axial side of the rotor 20, a fan of a different configuration may be disposed on the other end face 24f where the fan 4 is not disposed, or no fan may be disposed thereon.

[0093] In this embodiment, the second opposing surface 48 of the fan 4 is in direct contact with the end face 24f of the rotor core 24. However, a plate member made of resin, metal, or the like may be sandwiched between the fan 4 and the end face 24f. In this case, the plate member has through holes that overlap with the first air vent 24a, the second air vent 24b, and the cooling hole 24d. By covering the magnet hole 24h, the plate member can prevent fragments of the magnet 25 from detaching from the rotor 20 even if part of the magnet 25 inside the magnet hole 24h is lost.

[0094] <Modification> Next, we will explain modified examples of fans that can be used in the above-mentioned embodiments. In the following explanations of the modifications, the same components as those in the already-described embodiments or modifications will be given the same reference numerals, and their explanation will be omitted.

[0095] (Variation 1) 8 is a rear view of the fan (cap member) 104 of Modification 1. The fan 104 of this modification differs from the above-described embodiment mainly in the configuration of the first communication portion 181a.

[0096] Similar to the embodiment described above, the first communication portion 181a connects the hole 42 and the first gap G1. Furthermore, the first communication portion 181a of this modification passes through the fan 104 in the axial direction. The first communication portion 181a of this modification is a notched portion that expands the hole 42 toward the first gap G1.

[0097] According to the fan 104 of this embodiment, the cross-sectional area of ​​the flow path of the first communication portion 181a can be made larger than in the above-described embodiment. This increases the flow rate of air flowing from the hole 42 through the first communication portion 181a into the first gap G1. According to this modification, the rotor core 24 and the magnet 25 can be cooled efficiently.

[0098] (Variation 2) 9 is a rear view of the fan (cap member) 204 of Modification 2. The fan 204 of this modification differs from the above-described embodiment mainly in the configuration of the wall portions 280A and 280B.

[0099] As in the above-described embodiment, the first surface 40a of the fan 204 of this modified example is provided with a one-side recess 244A located on one circumferential side of one hole 42, and an other-side recess 244B located on the other circumferential side (-θ) of one hole 42. In this modified example, the wall 280A of the one-side recess 244A and the wall 280B of the other-side recess 244B have different shapes.

[0100] The wall 280A of the one-side recess 244A of this modified example has a first wall 81, a third wall 83, and a fourth wall 84 similar to the wall 80 of the above-described embodiment. Furthermore, the wall 280A of the one-side recess 244A of this modified example differs from the wall 80 of the above-described embodiment in the configuration of the second wall 282. In this modified example, the second wall 282 does not have a second communicating portion. Therefore, the second wall 282 extends circumferentially and connects the radially outer end of the third wall 83 to the radially outer end of the fourth wall 84. As a result, the second wall 282 covers the entire circumferential portion of the first gap G1 from the radially outer side. In other words, the wall 280A of the one-side recess 244A surrounds the first gap G1 when viewed in the axial direction. Furthermore, similar to the above-described embodiment, the wall 280A has a first communicating portion 81a. As a result, the first gap G1 of the one-side recess 244A functions as an inflow path. That is, air flows into the first gap G1 from the hole 42 via the first communication portion 81a. According to the fan 204 of this modified example, the second wall portion 282 of the one-side recess 244A prevents the air flowing into the first gap G1 from flowing outward in the radial direction, and the air flowing into the first gap G1 can be efficiently guided to the cooling hole 24d. As a result, a large flow rate of the air flowing into the cooling hole 24d can be ensured, and the rotor core 24 and the magnets 25 can be efficiently cooled.

[0101] The wall 280B of the other-side recess 244B of this modified example has a first wall 81, a third wall 83, and a fourth wall 84 similar to the wall 80 of the above-described embodiment. Furthermore, unlike the wall 80 of the above-described embodiment, the wall 280B of the other-side recess 244B of this modified example does not have a second wall. Therefore, the wall 280B opens the entire circumferential direction of the first gap G1 to the outside E of the fan 204. According to this modified example, when the first gap G1 of the other-side recess 244B functions as an exhaust path, air flowing into the first gap G1 from the cooling hole 24d can be efficiently exhausted to the outside E of the fan 204.

[0102] Note that the one-side recess 244A of this modified example is not connected to the outside E of the fan 204, and therefore does not function as an exhaust path. Similarly, the other-side recess 244B of this modified example is not likely to retain air flowing from the cooling holes 24d into the first gap G1, and therefore does not function as an inlet path. In other words, when the rotation direction R is set to the other circumferential side (-θ), the fan 204 of this modified example can suitably guide air to the cooling holes 24d and exhaust it. For example, the fan 204 of this modified example is suitable for use in a rotor 20 that is expected to rotate in only one direction.

[0103] (Variation 3) 10 is a rear view of the fan (cap member) 304 of Modification 3. The fan 304 of this modification is different from the above-described embodiment mainly in that the third wall portion 83 is provided with a third communication portion 383a.

[0104] As in the above-described embodiment, the third wall portion 83 is provided between the first recess 43 and the first gap G1 when viewed in the axial direction. The third wall portion 83 separates the first gap G1 from the second gap G2. The third wall portion 83 of this modification is provided with a third communication portion 383a that connects the internal space of the first recess 43 (the second gap G2) with the first gap G1. The third communication portion 383a of this modification is groove-shaped and recessed toward one axial side (+Y). The bottom surface of the third communication portion 383a (i.e., the surface facing the other axial side (-Y)) is arranged on the same plane as the first opposing surface 47 and the third opposing surface 49.

[0105] According to this modification, when the first gap G1 is made to function as an exhaust path, the air flowing into the first gap G1 from the cooling hole 24d can be sent to the second gap G2 via the third communication portion 383a. This allows the air exhausted from the cooling hole 24d to be exhausted to the outside E of the fan 304 via the second gap G2. As a result, it is possible to prevent the flow of the air F5 exhausted from the cooling hole 24d from stagnating in the first gap G1.

[0106] The third communication portion 383a of this modified example extends radially outward from the first gap G1 toward the second gap G2. A centrifugal force acting radially outward is applied to the air in the third communication portion 383a as the rotor 20 rotates. According to this modified example, the centrifugal force can smoothly guide the air in the third communication portion 383a to the first gap G1.

[0107] Although various embodiments and modifications of the present invention have been described above, the configurations and combinations thereof in each embodiment and modification are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments.

[0108] For example, in the above-described embodiment and its modified examples, the fan is fixed to the shaft by sandwiching the fan between the fixing member and the rotor core. However, the method for fixing the fan is not limited to this. Also, in the above-described embodiment, the fixing member is press-fitted onto the outer surface of the shaft. However, the method for fixing the fixing member is not limited to this.

[0109] The present technology can be configured as follows. (1) A rotor rotatable about a central axis, the rotor comprising: a plurality of magnets constituting a plurality of magnetic poles arranged in a circumferential direction; a rotor core holding the magnets; and a cap member arranged opposite an end face on one axial side of the rotor core, wherein the rotor core is provided with a cooling hole and a first air vent penetrating the rotor core in the axial direction; the magnetic pole has at least one of the magnets circumferentially surrounding at least a portion of the cooling hole; the cap member has a first opposing surface facing the end face with a gap therebetween and a hole portion penetrating the cap member in the axial direction, the hole portion overlapping an end portion on one axial side of the first air vent hole in the axial direction; the first opposing surface overlapping an end portion on one axial side of the cooling hole in the axial direction; and the hole portion connecting to the gap. (2) The rotor described in (1), wherein the cap member has a first wall portion that protrudes from the first opposing surface toward the other axial side and is provided between the hole portion and the gap when viewed from the axial direction, and the first wall portion is provided with a first communicating portion that connects the hole portion and the gap. (3) The rotor according to (2), wherein the first communication portion extends radially outward from the hole toward the gap. (4) The rotor according to (2) or (3), wherein the first communication portion axially penetrates the cap member. (5) A rotor described in any one of (1) to (4), wherein the cap member has a second wall portion that protrudes from the first opposing surface toward the other side in the axial direction and extends along a direction perpendicular to the radial direction, and the second wall portion is radially outward of the gap and aligned in a straight line with the first air vent and the cooling hole when viewed from the axial direction. (6) The rotor according to (5), wherein the second wall portion is provided with a second communication portion that connects the gap with the outside of the cap member. (7) The rotor described in (1), wherein the cap member has a wall portion protruding from the first opposing surface to the other axial side, the wall portion surrounding the gap when viewed from the axial direction, and the wall portion is provided with a first communicating portion connecting the hole portion and the gap. (8) A rotor described in any one of (1) to (7), wherein the rotor core is provided with a second air vent hole penetrating in the axial direction, and the cap member has a second opposing surface located on the other axial side of the first opposing surface and opposing the end face, an outer surface facing radially outward, and a recess provided in the second opposing surface, the recess overlapping in the axial direction with an end portion on one axial side of the second air vent hole and opening radially outward on the outer surface. (9) The rotor according to (8), wherein the cap member has a third wall portion that protrudes from the first opposing surface toward the other side in the axial direction and is provided between the recess and the gap as viewed from the axial direction. (10) The rotor according to (9), wherein the third wall portion is provided with a third communication portion that connects the internal space of the recess and the gap. (11) A rotating electric machine comprising: the rotor according to any one of (1) to (10); and a stator radially opposed to the rotor. (12) A drive device comprising: a rotating electric machine according to (11); and a power transmission unit that transmits power of the rotating electric machine. [Explanation of symbols]

[0110] 2...rotating electric machine, 4,104,204,304...fan (cap member), 20...rotor, 20P...magnetic pole, 24...rotor core, 24a...first vent hole, 24b...second vent hole, 24d...cooling hole, 24f...end face, 25...magnet, 30...stator, 40c...outer surface, 42...hole portion, 47...first opposing surface, 48...second opposing surface, 49...third opposing surface, 50...power transmission portion, 80, 280A, 280B...wall portion, 81...first wall portion, 81a, 181a...first communication portion, 82, 282...second wall portion, 82a...second communication portion, 83...third wall portion, 100...drive device, 383a...third communication portion, E...outside, G1...first gap (gap), J...central axis, θ...circumferential direction

Claims

1. A rotor rotatable about a central axis, a plurality of magnets constituting a plurality of magnetic poles arranged in a circumferential direction; a rotor core that holds the magnet; a cap member disposed opposite to one axial end face of the rotor core, The rotor core is provided with a cooling hole and a first vent hole that penetrate the rotor core in the axial direction, the magnetic pole includes at least one magnet that circumferentially surrounds at least a portion of the cooling hole, The cap member is a first opposing surface opposing the end surface with a gap therebetween; a hole portion that penetrates the cap member in the axial direction, the hole portion overlaps with one axial end of the first air vent hole, the first opposing surface overlaps with one axial end of the cooling hole, The hole is connected to the gap. Rotor.

2. the cap member has a first wall portion that protrudes from the first opposing surface to the other axial direction and is provided between the hole portion and the gap as viewed from the axial direction, The first wall portion is provided with a first communication portion that connects the hole portion and the gap. The rotor of claim 1 .

3. The first communication portion extends radially outward from the hole portion toward the gap. The rotor of claim 2 .

4. The first communication portion axially penetrates the cap member. The rotor of claim 2 .

5. the cap member has a second wall portion that protrudes from the first opposing surface to the other axial direction and extends along a direction perpendicular to the radial direction, The second wall portion is located radially outward of the gap and aligned in a straight line with the first vent hole and the cooling hole when viewed in the axial direction. The rotor of claim 1 .

6. The second wall portion is provided with a second communication portion that connects the gap with the outside of the cap member. The rotor according to claim 5 .

7. the cap member has a wall portion that protrudes from the first opposing surface to the other axial side, The wall portion surrounds the gap when viewed in the axial direction, The wall portion is provided with a first communication portion that connects the hole portion and the gap. The rotor of claim 1 .

8. The rotor core is provided with a second vent hole penetrating in the axial direction, The cap member is a second opposing surface located on the other axial side of the first opposing surface and opposing the end surface; an outer surface facing radially outward; a recess provided on the second opposing surface, the recess overlaps with one axial end of the second air vent hole in the axial direction and opens radially outward on the outer surface. The rotor of claim 1 .

9. the cap member has a third wall portion that protrudes from the first opposing surface toward the other side in the axial direction and is provided between the recessed portion and the gap as viewed in the axial direction. The rotor of claim 8 .

10. The third wall portion is provided with a third communication portion that connects the internal space of the recess and the gap. The rotor of claim 9.

11. A rotor according to any one of claims 1 to 10; a stator radially opposed to the rotor, Rotating electric motor.

12. a rotating electric machine according to claim 11; a power transmission unit that transmits power of the rotating electric machine, Drive unit.

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