Rotor, rotating electrical machine, and drive device

Abstract

The invention provides a rotor, a rotating electrical machine, and a drive device. The rotor is rotatable about a central axis and has: a shaft extending along the central axis; a ring-shaped rotor core into which the shaft is inserted; and a cap portion provided on the shaft on one side of the rotor core in the axial direction, the cap portion having: an opposing portion surrounding the shaft from the outside in the radial direction and contacting an end surface of the rotor core facing the one side in the axial direction; and a cover part which is located on one side in the axial direction of the facing part, is provided with a gap between the inner peripheral surface of the facing part and the outer peripheral surface of the shaft, and covers the gap from the one side in the axial direction.

Description

Technical Field

[0001] The invention relates to a rotor, a rotating electrical machine and a driving device. Background Art

[0002] In a rotating electrical machine, a rotor having a shaft and a rotor core fixed to each other is known. As a fastening structure between the shaft and the rotor core, a structure fixed by key fitting and a structure fixed by press fitting are known. For example, Patent Document 1 discloses a structure in which a shaft and a rotor core are key fitted.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2011-259689

[0004] When the shaft is inserted into the through hole provided in the rotor core, contamination may be generated due to the contact between the shaft and the rotor core when the shaft and the rotor core are assembled. Therefore, post-processing for removing the contamination is required after the insertion, which complicates the manufacturing process. Summary of the invention

[0005] In view of the above circumstances, one object of the present invention is to provide a rotor, a rotating electrical machine, and a drive device capable of suppressing the generation of contaminants when a shaft and a rotor core are assembled.

[0006] One embodiment of the present invention is a rotor that can rotate around a central axis, and the rotor comprises: a shaft that extends along the central axis; a rotor core that is annular and for the shaft to be inserted into; and a cap portion that is arranged on the shaft on one axial side of the rotor core, the cap portion comprising: an opposing portion that surrounds the shaft from the radially outer side and contacts the end surface of the rotor core that faces the axial side; and a cover portion that is located on one axial side of the opposing portion, a gap being arranged between the inner circumferential surface of the opposing portion and the outer circumferential surface of the shaft, the cover portion covering the gap from one axial side.

[0007] One aspect of the present invention is a rotating electrical machine including the above-mentioned rotor and a stator surrounding the rotor from the radially outer side.

[0008] One aspect of the present invention is a drive device including the above-described rotating electric machine and a power transmission mechanism for transmitting power of the rotating electric machine.

[0009] According to one aspect of the present invention, it is possible to provide a rotor, a rotating electrical machine, and a drive device capable of suppressing generation of contaminants when a shaft and a rotor core are assembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a conceptual diagram of a driving device according to an embodiment.

[0011] Figure 2It is a perspective view of the shaft of the embodiment.

[0012] Figure 3 It is an exploded perspective view of the cap part of the embodiment.

[0013] Figure 4 It is a perspective view of the cap part of embodiment.

[0014] Figure 5 is with Figure 1 An enlarged cross-sectional view of a portion corresponding to region V is shown.

[0015] Figure 6 This is a partial cross-sectional view of the rotor of Modification 1.

[0016] Figure 7 This is a partial cross-sectional view of a rotor according to Modification 2.

[0017] Figure 8 This is a partial cross-sectional view of a rotor according to Modification 3.

[0018] Fig. 9 This is a partial cross-sectional view of a rotor according to Modification 4.

[0019] Fig.10 This is a partial cross-sectional view of the rotor of Modification 5.

[0020] Fig.11 It is a schematic cross-sectional view of the opposing portion and the shaft of Modification Example 6.

[0021] Description of symbols

[0022] 1: drive device; 2: rotating electrical machine; 5: fixing member; 5b, 405b, 505b: cover; 5d: cylinder; 5h: second hole; 5q, 24q, 40q, 405q, 440q, 540q, 624q, 640q: inner circumference; 20, 120, 220, 320, 420, 520: rotor; 21, 121, 521: shaft; 21h, 21i, 21j: groove; 21p, 521p: outer circumference; 24, 624: rotor core; 24a, 24b : Vent hole; 24f: end face; 29: recess; 30: stator; 40, 240, 440, 540, 640: opposing portion; 40h, 240h: first hole portion; 42: through hole; 50: power transmission mechanism; 60, 260, 460, 560, 660: cap portion; 121p: first outer peripheral surface; 121q: second outer peripheral surface; 121t: outer peripheral step surface; 240p: first inner peripheral surface; 240q: second inner peripheral surface; 240t: inner peripheral step surface; G: gap; J: center axis. DETAILED DESCRIPTION

[0023] Hereinafter, the drive device of the embodiment will be described with reference to the accompanying drawings. In the following description, unless otherwise specified, the direction parallel to the central axis J of the rotary electric machine 2 (Y-axis direction) is referred to as the "axial direction", the radial direction centered on the central axis J is referred to as the "radial direction", and the circumferential direction centered on the central axis J, that is, the direction around the central axis J is referred to as the "circumferential direction". However, the above-mentioned "parallel direction" also includes a substantially parallel direction.

[0024] <Drive device>

[0025] Figure 1 This is a conceptual diagram of the driving device 1 according to the embodiment.

[0026] The drive device 1 of the present embodiment is mounted on a vehicle having a rotating electric machine as a power source, 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.

[0027] The drive device 1 includes a rotary electric machine 2, a power transmission mechanism 50, a resolver 28, and a housing 6. The drive device 1 may further include an inverter (not shown) for controlling the rotary electric machine 2.

[0028] The housing 6 accommodates the rotating electrical machine 2, the power transmission mechanism 50, and the resolver 28. Inside the housing 6, spaces accommodating the rotating electrical machine 2, the power transmission mechanism 50, and the resolver 28 are partitioned from each other.

[0029] The rotary transformer 28 includes a rotary transformer rotor 28a and a rotary transformer stator 28b. The rotary transformer rotor 28a includes a plurality of magnets arranged in the circumferential direction. The rotary transformer rotor 28a rotates around the central axis J together with the rotor 20 of the rotary electric machine 2. The rotary transformer stator 28b is fixed to the housing 6. The rotary transformer stator 28b surrounds the rotary transformer rotor 28a from the radially outer side. The rotary transformer stator 28b includes a coil that is excited due to the change in magnetic flux accompanying the rotation of the rotary transformer rotor 28a. The rotary transformer 28 measures the rotation angle of the rotary transformer rotor 28a by detecting the excitation of the coil.

[0030] <Power transmission mechanism>

[0031] The power transmission mechanism 50 is connected to the rotor 20 to transmit the power of the rotary electric machine 2 and output it to the output shaft 57. The power transmission mechanism 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 respectively mounted at the front ends of the pair of output shafts 57.

[0032] The first shaft 54 ​​extends in the axial direction with the center axis J as the center. The first shaft 54 ​​is connected to the rotor 20 of the rotary electric machine 2 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 with the intermediate axis J2 parallel to the center axis J as the center. 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 the ring gear 56g of the differential device 56. The differential device 56 absorbs the speed difference between the left and right wheels when the vehicle turns, and transmits the torque transmitted from the third gear 53 to the output shaft 57. The torque output from the rotary 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 the pair of output shafts 57 via the differential mechanism portion of the differential device 56. The output shaft 57 rotates about the differential axis J3.

[0033] <Rotary electric machines>

[0034] The rotating electrical machine 2 of this embodiment is an inner rotor type three-phase AC motor. The rotating electrical machine 2 has both the function of outputting power as a motor and the function of generating electricity as a generator. The rotating electrical machine 2 can be used as either a motor or a generator. In addition, the structure of the rotating electrical machine 2 is not limited to this embodiment, and for example, it can also be an AC motor with four or more phases.

[0035] The rotary electric machine 2 includes a rotor 20 rotatable about a central axis J extending in the horizontal direction, and a stator 30 located radially outside the rotor 20 .

[0036] <Stator>

[0037] The stator 30 is held by the housing 6. The stator 30 surrounds the rotor 20 from the radially outer side. The stator 30 includes an annular stator core 32 centered on the central axis J, a coil 31 attached to the stator core 32, and an insulating material (not shown) interposed between the stator core 32 and the coil 31.

[0038] The stator core 32 has an annular core back and a plurality of teeth extending radially inward from the core back and arranged circumferentially. Coil wires are arranged between the teeth. The coil wires located between adjacent teeth constitute the coil 31. The coil 31 has a pair of coil ends 31a protruding axially from the end faces on both axial sides of the stator core 32. The coil ends 31a form a portion of the coil wire that connects the slots of the stator core 32.

[0039] <Rotor>

[0040] The rotor 20 includes a shaft 21 , 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 , and a pair of cap portions 60 .

[0041] The rotor core 24 is in a columnar shape extending along the central axis J. The rotor core 24 has a pair of end faces 24f facing both sides in the axial direction. In addition, a third hole portion 24c, a plurality of vent holes 24a, 24b, and a plurality of retaining holes 24h are provided in the rotor core 24. The third hole portion 24c, the vent holes 24a, 24b, and the retaining holes 24h penetrate the rotor core 24 in the axial direction.

[0042] The third hole portion 24c extends in the axial direction around the central axis J. The shaft 21 is press-fitted into the third hole portion 24c. That is, the shaft 21 of the present embodiment is press-fitted into the inner peripheral surface 24q of the rotor core 24 and fixed to the inner peripheral surface 24q.

[0043] When viewed from the axial direction, the third hole portion 24c of the present embodiment is substantially circular. However, the shape of the third hole portion 24c is not limited to the present embodiment. The rotor core 24 is annular by providing the third hole portion 24c. In addition, in this specification, "annular" refers to a shape composed of a series of loops, and is not necessarily limited to the case of a circular ring shape. Therefore, when the rotor core 24 is viewed from the axial direction, the surface facing the radial outside and the surface facing the radial inside of the rotor core 24 may not be circular.

[0044] The plurality of vent holes 24a and 24b include the first vent hole 24a and the second vent hole 24b. That is, the rotor core 24 is provided with the first vent hole 24a and the second vent hole 24b. In the rotor 20 of the present embodiment, for example, four first vent holes 24a and four second vent holes 24b are provided. In the first vent hole 24a and the second vent hole 24b, the flow directions of the air flowing inside are different from each other.

[0045] A plurality of retaining holes 24h are arranged along the circumferential direction. Magnets 25 are respectively accommodated in the retaining holes 24h. The magnets 25 are fixed to the inner side surfaces of the retaining holes 24h, for example, by adhesives or the like. In addition, the magnets 25 can also be fixed in the retaining holes 24h by other fixing means such as crimping or pressing, foaming sheets, or a combination of these means. The openings on both axial sides of the retaining holes 24h are respectively covered by the cap portions 60. Thus, even if a part of the magnet 25 is missing, it is possible to prevent fragments of the magnet 25 from flying out of the retaining holes 24h of the rotor 20.

[0046] The shaft 21 extends along the central axis J. The shaft 21 is rotatable about the central axis J. The rotor core 24, a pair of caps 60, and a rotary transformer rotor 28a are fixed to the outer peripheral surface 21p of the shaft 21. The pair of caps 60 are located on both axial sides of the rotor core 24. The rotary transformer rotor 28a is fixed to the end of the shaft 21 on one axial side (+Y).

[0047] Figure 2 2 is a perspective view of the shaft 21. A step is provided on the outer peripheral surface 21p of the shaft 21. The outer peripheral surface 21p of the shaft 21 has a first portion 21a, a second portion 21b, two third portions 21c, a fourth portion 21d, a fifth portion 21e, a sixth portion 21f, and a seventh portion 21g. The outer diameters of the first portion 21a, the second portion 21b, the third portion 21c, the fourth portion 21d, the fifth portion 21e, the sixth portion 21f, and the seventh portion 21g are different from each other. The outer diameter of the shaft 21 decreases as it moves toward one side and the other side in the axial direction relative to the fourth portion 21d. The following describes each portion.

[0048] The fourth portion 21d is a portion of the outer peripheral surface 21p having the largest outer diameter. In addition, the fourth portion 21d is a portion of the outer peripheral surface 21p having the largest length dimension in the axial direction. The fourth portion 21d is a portion facing the inner peripheral surface 24q of the rotor core 24. That is, the shaft 21 is pressed into the rotor core 24 at the fourth portion 21d. A plurality of grooves 21h are provided in the fourth portion 21d. The grooves 21h are provided, for example, by mechanical processing such as knurling on the fourth portion 21d. The plurality of grooves 21h extend in the axial direction in the fourth portion 21d. In the present embodiment, the plurality of grooves 21h extend over the entire axial length of the fourth portion 21d. In addition, the plurality of grooves 21h are arranged at intervals in the circumferential direction in the fourth portion 21d. The plurality of grooves 21h are arranged at substantially equal intervals in the entire circumferential region of the fourth portion 21d. In addition, the grooves 21h only need to be arranged in at least a portion of the fourth portion 21d in the axial direction. Similarly, the groove portion 21h only needs to be provided in at least a partial region of the fourth portion 21d in the circumferential direction.

[0049] The third part 21c is located on one side and the other side of the fourth part 21d in the axial direction. The two third parts 21c have shapes that are symmetrical to each other in the axial direction. The outer diameter of the third part 21c is smaller than the outer diameter of the fourth part 21d. A cap portion 60 is fixed to the third part 21c. A plurality of grooves 21i are provided in the third part 21c by, for example, performing mechanical processing such as knurling. The plurality of grooves 21i extend in the axial direction in the third part 21c. In the present embodiment, the plurality of grooves 21i extend over the entire axial length of the third part 21c. In addition, the plurality of grooves 21i are arranged at intervals in the circumferential direction in the third part 21c. In the present embodiment, the plurality of grooves 21i are arranged at approximately equal intervals in the entire circumferential region of the third part 21c. In addition, the grooves 21i only need to be arranged in at least a portion of the third part 21c in the axial direction. Similarly, the grooves 21i only need to be arranged in at least a portion of the circumferential region of the third part 21c.

[0050] The second portion 21b is provided on the other axial side (-Y side) of the third portion 21c located on one of the other axial sides (-Y side). The outer diameter of the second portion 21b is smaller than the outer diameter of the third portion 21c.

[0051] The first portion 21a is provided on the other axial side (-Y side) of the second portion 21b. The first portion 21a is located at the end of the other axial side (-Y side) of the shaft 21. The outer diameter of the first portion 21a is smaller than the outer diameter of the second portion 21b. A bearing is mounted on the first portion 21a, for example, and is supported by the housing 6.

[0052] The fifth portion 21e is provided on one axial side (+Y side) of the third portion 21c located on the other side of the first axial side (+Y side). The outer diameter of the fifth portion 21e is smaller than the outer diameter of the third portion 21c.

[0053] The sixth portion 21f is provided on one axial side (+Y side) of the fifth portion 21e. The outer diameter of the sixth portion 21f is smaller than the outer diameter of the fifth portion 21e. A bearing is attached to the sixth portion 21f, for example, and the sixth portion 21f is supported by the housing 6.

[0054] The 7th part 21g is provided on one axial side (+Y side) of the 6th part 21f. The 7th part 21g is located at the end of one axial side (+Y side) of the shaft 21. The outer diameter of the 7th part 21g is smaller than the outer diameter of the 6th part 21f. The rotary transformer rotor 28a is fixed to the 7th part 21g by press-fitting. A plurality of grooves 21j are provided in the 7th part 21g, for example, by mechanical processing such as knurling. A plurality of grooves 21j are provided at the end of one axial side (+Y side) of the 7th part 21g. In addition, a plurality of grooves 21j are arranged at intervals in the circumferential direction in the 7th part 21g. In the present embodiment, a plurality of grooves 21j are arranged at approximately equal intervals in the entire circumferential region of the 7th part 21g. In addition, the grooves 21j only need to be provided in at least a portion of the 7th part 21g in the circumferential direction. Since the groove 21j is provided in the seventh portion 21g, a part of the inner peripheral surface of the resolver rotor 28a is deformed and enters the groove 21j when press-fitting. Thus, the resolver rotor 28a can be stably fixed to the shaft 21.

[0055] like Figure 1 As shown, the shaft 21 has a recessed portion 29 opened at the end on the other side (-Y side) in the axial direction. When viewed from the axial direction, the recessed portion 29 is a substantially circular shape centered on the central axis J. The first shaft 54 ​​of the power transmission mechanism 50 is inserted into the recessed portion 29. The inner circumferential surface of the recessed portion 29 and the outer circumferential surface of the first shaft 54 ​​are connected, for example, by spline fitting. That is, the shaft 21 has a recessed portion 29 opened at the end on one side or the other side in the axial direction, and the recessed portion 29 is for inserting the end of another shaft.

[0056] The end of the recessed portion 29 on one axial side (+Y side) of the present embodiment is located closer to the other axial side (-Y side) than the fourth portion 21d of the shaft 21. As described above, the fourth portion 21d is pressed into the rotor core 24. Therefore, the recessed portion 29 is arranged at a position different from the rotor core 24 in the axial direction. According to the present embodiment, the rigidity of the portion of the shaft 21 that overlaps with the rotor core 24 in the axial direction can be suppressed from being reduced by the recessed portion 29. That is, the deformation of the shaft 21 due to the press-fitting into the rotor core 24 can be suppressed.

[0057] In addition, in the present embodiment, a part of the recess 29 is arranged radially inside the third portion 21c of the shaft 21. In the third portion 21c, although it is a portion pressed into the cap 60, the force applied from the cap 60 to the third portion 21c is smaller than the force applied from the rotor core 24 to the fourth portion 21d. Therefore, even if the axial position of the recess 29 overlaps the axial position of the third portion 21c, the shaft 21 is unlikely to be deformed.

[0058] <Hat>

[0059] like Figure 1 As shown, the cap 60 is located at one axial side and the other axial side of the rotor core 24. The cap 60 is provided on the shaft 21. The cap 60 has a fan 4 and a fixing member 5.

[0060] In the present embodiment, the cap 60 is composed of a plurality of parts (the fan 4 and the fixing part 5). However, the cap 60 may also be composed of a single part. In addition, the fan 4 and the fixing part 5 of the present embodiment are parts different from the shaft 21. However, a part or the whole of the cap 60 may also be a part of the shaft 21. That is, at least a part of the part constituting the cap 60 is constituted as one part with the shaft 21.

[0061] The pair of caps 60 have the same structure. In the following description, when distinguishing between the pair of caps 60, one of them located on the +Y side of the rotor core 24 is referred to as the first cap 60A, and the other one located on the -Y side of the rotor core 24 is referred to as the second cap 60B. In addition, when distinguishing between the pair of fans 4, the fan 4 of the first cap 60A is referred to as the first fan 4A, and the fan 4 of the second cap 60B is referred to as the second fan 4B.

[0062] The fans 4 are respectively mounted on one axial side and the other side of the rotor core 24. That is, one fan 4 of a pair of fans 4 is mounted on the end face 24f of the rotor core 24 facing one axial side, and the other fan 4 of a pair of fans 4 is mounted on the end face 24f of the rotor core 24 facing the other axial side. The pair of fans 4 rotate around the central axis J together with the rotor core 24. The pair of fans 4 are respectively located radially inside the coil end 31a. In the present embodiment, the pair of fans 4 are of the same shape. The mounting angles of the pair of fans 4 around the central axis J relative to the rotor core 24 are different from each other.

[0063] The fan 4 of this embodiment is made of aluminum alloy and is formed by aluminum die casting. In addition, the fan 4 may be made of a resin material or other metal material.

[0064] The fan 4 of the present embodiment covers the end surface 24f of the rotor core 24. In addition, the fan 4 covers the plurality of retaining holes 24h of the rotor core 24. Thus, it is possible to suppress the magnet 25 from flying out of the retaining hole 24h. In addition, even when a portion of the magnet 25 is missing, the fan 4 can suppress fragments of the magnet 25 from flying out of the rotor 20. That is, according to the present embodiment, the fan 4 also functions as an end plate that covers the opening of the retaining hole 24h. Therefore, according to the present embodiment, it is not necessary to separately provide a component that covers the opening of the retaining hole 24h, and the number of components can be reduced and the rotor 20 can be easily manufactured.

[0065] The fan 4 is provided with a plurality of inflow passages 45 and a plurality of outflow passages 46. The plurality of inflow passages 45 and the plurality of outflow passages 46 are respectively connected to any one of the plurality of ventilation holes 24a and 24b.

[0066] The installation angles of the first fan 4A and the second fan 4B relative to the rotor core 24 around the central axis J are different from each other. When the first fan 4A is installed on the rotor core 24, the inlet path 45 is connected to the second vent 24b, and the outlet path 46 is connected to the first vent 24a. On the other hand, when the second fan 4B is installed on the rotor core 24, the inlet path 45 is connected to the first vent 24a, and the outlet path 46 is connected to the second vent 24b. Therefore, the first vent 24a connects the inlet path 45 of the second fan 4B and the outlet path 46 of the first fan 4A. In addition, the second vent 24b connects the inlet path 45 of the first fan 4A and the outlet path 46 of the second fan 4B.

[0067] The outflow path 46 extends radially and opens radially outward. When the rotor 20 rotates, the centrifugal force caused by the rotation of the fan 4 around the central axis J is applied to the air inside the outflow path 46. As a result, the air inside the outflow path 46 flows out radially outward. As the air flows out from the outflow path 46, a negative pressure is generated inside the vents 24a, 24b connected to the outflow path 46. As a result, the air flows into the vents 24a, 24b via the inflow path 45. An axial flow of air is formed in the vents 24a, 24b. Furthermore, in the present embodiment, the air flowing out radially outward from the outflow path 46 contacts the coil end 31a and cools the coil 31.

[0068] Figure 3 It is an exploded perspective view of the first cap portion 60A. Figure 4 It is from Figure 3 The three-dimensional view of the first cap portion 60A viewed from different directions. Figure 3 and Figure 4 In the description, the positions and shapes of the various parts of the cap 60 are described based on the posture of the first cap 60A. The second cap 60B is fixed to the shaft 21 and the rotor core 24 at a position and posture in which the following description is reversed in the axial direction.

[0069] like Figure 3 As shown, the fan 4 includes an opposing portion 40 , an annular rib 41 , and a plurality of (four in this embodiment) convex portions 47 .

[0070] The opposing portion 40 is in the shape of a disk extending perpendicularly to the axial direction. When viewed from the axial direction, the opposing portion 40 is in the shape of a substantially circular shape centered on the central axis J. The opposing portion 40 has a first surface 40a facing the other axial side (-Y side) and a second surface 40b facing the axial one side (+Y side). The first surface 40a faces the end surface 24f of the rotor core 24.

[0071] like Figure 4 As shown, the facing portion 40 is provided with a first hole portion 40h, a plurality of (four in this embodiment) through holes 42, and a plurality of (four in this embodiment) recessed portions 43. The first hole portion 40h and the through holes 42 penetrate the facing portion 40 in the axial direction.

[0072] When viewed from the axial direction, the first hole 40h is substantially circular centered on the central axis J. The shaft 21 is inserted into the first hole 40h. The inner diameter of the first hole 40h is larger than the outer diameter of the shaft 21. The method of fixing the fan 4 to the shaft 21 will be described later.

[0073] When viewed from the axial direction, the through holes 42 and the recesses 43 are arranged alternately in the circumferential direction. When the first fan 4A is viewed from the axial direction, the opening of the through hole 42 on the first surface 40a overlaps with the second ventilation hole 24b, and the recess 43 overlaps with the first ventilation hole 24a. The recess 43 is provided on the first surface 40a. The opening on the other axial side (-Y side) of the recess 43 is covered by the end face 24f of the rotor core 24. The recess 43 has a connecting portion 43a overlapping with the first ventilation hole 24a and a groove portion 43b extending radially outward from the connecting portion 43a and opening at the outer edge of the opposing portion 40. In addition, the space surrounded by the recess 43 and the end face 24f of the rotor core 24 is connected to the ventilation hole 24a to form an outflow path 46. On the other hand, the through hole 42 is connected to the ventilation hole 24b to form an inflow path 45.

[0074] like Figure 3 As shown, the annular rib 41 protrudes from the second surface 40b of the opposing portion 40 to one side (+Y side) in the axial direction. The annular rib 41 is substantially annular centered on the central axis J. The annular rib 41 is provided along the outer edge of the second surface 40b. The annular rib 41 can be used, for example, as a cutting allowance for correcting the imbalance of the rotor 20. That is, in the balancing correction process after the rotor 20 is assembled, by machining a portion of the annular rib 41, the imbalance of the rotor 20 can be corrected. As the machining performed on the annular rib 41, for example, it is considered to perform cutting on the surface of the annular rib 41 facing the radial outside.

[0075] A plurality of convex portions 47 protrude from the second surface 40b of the opposing portion 40 toward one axial side (+Y side). The plurality of convex portions 47 are arranged at equal intervals along the circumferential direction on the radial inner side of the annular rib 41. The convex portions 47 are located between the through holes 42 adjacent in the circumferential direction. In addition, the convex portions 47 overlap with the concave portions 43 when viewed from the axial direction. The convex portion 47 has an inner side surface 47f facing the radial inner side and a front end surface 47h facing one axial side. The inner side surface 47f is a substantially arc-shaped surface centered on the central axis J when viewed from the axial direction.

[0076] The front end surface 47h of the convex portion 47 is provided with a groove 40g. The groove 40g extends in the radial direction and is recessed from the front end surface 47h toward the other axial side (-Y side). The groove 40g is provided in two of the four convex portions 47 that are located on opposite sides with respect to the central axis J.

[0077] The fixing member 5 is disposed on one axial side (+Y side) of the fan 4. The fixing member 5 is axially opposed to the fan 4. The fixing member 5 is made of, for example, a metal material.

[0078] The fixing member 5 includes a barrel portion 5d into which the shaft 21 is pressed and a cover portion 5b that protrudes radially outward from the barrel portion 5d and extends circumferentially. The barrel portion 5d is cylindrical with the central axis J as the center. The inner circumferential surface of the barrel portion 5d constitutes the second hole portion 5h. That is, the fixing member 5 includes the second hole portion 5h into which the shaft 21 is inserted. The fixing member 5 of the present embodiment has a simple shape and can therefore be easily manufactured by a manufacturing method such as stamping.

[0079] The fixing member 5 is fixed to the outer side surface of the shaft 21 by pressing the shaft 21 into the cylindrical portion 5d. The cover portion 5b is arranged radially inward of the plurality of convex portions 47. The outer edge 5c of the cover portion 5b is a circle centered on the central axis J when viewed from the axial direction. The outer edge 5c of the cover portion 5b is embedded in the inner side surface 47f of the plurality of convex portions 47. Thus, the fan 4 is radially aligned with respect to the cover portion 5b. In addition, the cover portion 5b contacts the second surface 40b of the fan 4 from one axial side (+Y side). The fan 4 is axially fixed to the shaft 21 by being clamped between the rotor core 24 and the cover portion 5b. In addition, the outer edge 5c of the cover portion 5b is not limited to a circle when viewed from the axial direction, and may also be other shapes such as a polygon.

[0080] The outer edge 5c of the fixing member 5 of the present embodiment is provided with a plurality of (two in the present variation) protruding portions 5a protruding radially outward. The two protrusions 5a are arranged on opposite sides (i.e., symmetrically) relative to the central axis J. The protrusions 5a are arranged in the groove 40g. The surface of the protrusion 5a facing the circumferential direction is circumferentially opposed to the inner side surface of the groove 40g. Thus, the fixing member 5 restricts the circumferential movement of the fan 4 relative to the fixing member 5.

[0081] Figure 5 is with Figure 1 FIG. 1 is an enlarged cross-sectional view of a portion of the rotor 20 corresponding to a region V. FIG.

[0082] like Figure 5 As shown, the facing portion 40 is in contact with the end surface 24f of the rotor core 24 at the first surface 40a, and is in contact with the cover portion 5b of the fixing member 5 at the second surface 40b.

[0083] The outer edge of the cover portion 5b of the present embodiment is located radially inward of the through hole 42. That is, when viewed from the axial direction, the cover portion 5b is provided at a position different from the through hole 42. Therefore, the cover portion 5b is less likely to hinder the flow of air passing through the through hole 42. The cover portion 5b may also be located radially outward of the through hole 42 between adjacent through holes 42 in the circumferential direction.

[0084] The shaft 21 is pressed into the third hole portion 24c of the rotor core 24. Therefore, the inner circumferential surface 24q of the third hole portion 24c contacts the outer circumferential surface 21p of the shaft 21 in the entire circumferential region. Similarly, the shaft 21 is pressed into the second hole portion 5h of the fixing member 5. Therefore, the inner circumferential surface 5q of the second hole portion 5h contacts the outer circumferential surface 21p of the shaft 21 in the entire circumferential region. On the other hand, the inner diameter of the first hole portion 40h provided in the opposing portion 40 is larger than the outer diameter of the shaft 21. Therefore, a gap G is provided between the inner circumferential surface 40q of the first hole portion 40h and the outer circumferential surface 21p of the shaft 21. In the present embodiment, the gap G is provided in an annular shape in the entire circumferential region around the central axis J. In addition, the gap G only needs to extend in the circumferential direction around the central axis J, and does not necessarily have to be annular. For example, the gap G may extend in the circumferential direction when viewed from the axial direction, and may extend in a substantially C-shaped or substantially arc-shaped shape.

[0085] As described above, the fourth portion 21d into which the rotor core 24 is pressed and the third portion 21c into which the fixing member 5 is pressed are provided on the outer peripheral surface 21p of the shaft 21. The outer diameter of the third portion 21c is smaller than the outer diameter of the fourth portion 21d. Therefore, a step portion 21k is provided at the boundary portion between the third portion 21c and the fourth portion 21d. On the other hand, in the present embodiment, the inner diameter of the first hole portion 40h of the opposing portion 40 is constant over the entire axial length. In addition, the inner peripheral surface 40q of the opposing portion 40 faces the outer peripheral surface 21p of the shaft 21 at the boundary portion between the third portion 21c and the fourth portion 21d. Therefore, the radial dimension of the gap G at the end portion on one axial side (+Y side) between the inner peripheral surface 40q and the outer peripheral surface 21p is larger than the radial dimension of the gap G at the end portion on the other axial side (-Y side).

[0086] The end of the other axial side (-Y) of the gap G is covered by the rotor core 24. On the other hand, the end of one axial side (+Y) of the gap G is covered by the cover portion 5b of the fixing member 5. Therefore, the gap G is a closed space. In addition, here, "closed space" refers to a state in which fine solid pollutants such as metal dust in the gap G are not discharged to the outside or are difficult to discharge. That is, the gap G may not be in a state in which the entry and exit of the fluid is suppressed (the so-called sealed state).

[0087] That is, according to the present embodiment, the cap portion 60 includes: the opposing portion 40 that surrounds the shaft 21 from the radially outer side and contacts the end surface 24f of the rotor core 24; and the cover portion 5b that is located on one axial side (+Y) of the opposing portion 40. In addition, a gap G is provided between the inner peripheral surface 40q of the opposing portion 40 and the outer peripheral surface 21p of the shaft 21. The cover portion 5b covers the gap G from one axial side.

[0088] When the shaft 21 is inserted into the third hole 24c of the rotor core 24, when the shaft 21 contacts the inner peripheral surface 24q of the rotor core 24, a part of one of them may be cut off and contaminants may be generated. In particular, when the shaft 21 is pressed into the inner peripheral surface 24q of the rotor core 24 as in the present embodiment, contaminants may be easily generated. When the shaft 21 is inserted into the third hole 24c of the rotor core 24, contaminants are easily accumulated near the opening of the third hole 24c on the side where the shaft 21 is inserted.

[0089] According to the present embodiment, the opposing portion 40 surrounds the opening of the third hole portion 24c from the radially outer side. Therefore, contaminants can be contained in the gap G between the inner peripheral surface 24q of the opposing portion 40 and the outer peripheral surface 21p of the shaft 21. In addition, the gap G is covered by the cover portion 5b of the fixing member 5 from one axial side, so that contaminants in the gap G can be retained in the gap G. According to the present embodiment, even if contaminants are generated when the shaft 21 and the rotor core 24 are assembled, there is no need to perform a separate process for removing the contaminants, and the manufacturing process can be simplified.

[0090] The gap G of this embodiment extends in a ring shape along the circumferential direction. Therefore, the gap G can receive and accumulate pollutants in the entire circumferential direction. Figure 3 As shown in the figure, the cover portion 5b of the fixing member 5 is embedded in the inner side surface 47f of the plurality of convex portions 47 of the fan 4, so that the center position of the fan 4 is aligned with the center of the shaft 21. As a result, the radial width of the gap G between the inner peripheral surface 40q of the first hole portion 40h and the outer peripheral surface 21p of the shaft 21 can be made substantially uniform along the circumferential direction. As a result, the gap G can uniformly accumulate pollutants at any position in the circumferential direction.

[0091] According to this embodiment, the shapes of the shaft 21 and the rotor core 24 can be simplified compared to the case where the rotor core and the shaft are key-fitted. Thus, the shaft 21 and the rotor core 24 can be easily manufactured, the manufacturing cost can be reduced, and the rotor 20 can be easily manufactured.

[0092] In addition, according to the present embodiment, a groove 21h is provided in the portion of the outer circumferential surface 21p of the shaft 21 that faces the inner circumferential surface 24q of the rotor core 24. Therefore, when press-fitting, a portion of the inner circumferential surface 24q of the rotor core 24 is deformed and enters the groove 21h. Thus, the shaft 21 and the rotor core 24 can be firmly fixed in the circumferential direction.

[0093] In addition, in the present embodiment, the case where the shaft 21 and the rotor core 24 are fixed by pressing the shaft 21 into the rotor core 24 is described, but the fixing method of the shaft 21 and the rotor core 24 is not limited to the present embodiment. For example, the shaft 21 and the rotor core 24 may be fixed to each other by fitting a key into a key groove provided on the outer peripheral surface of the shaft and the inner peripheral surface of the rotor core, respectively. Even in this case, when the shaft and the rotor core are assembled, contaminants generated by the contact between the two can be contained in the gap G. In addition, the shaft 21 and the rotor core 24 may be fixed by an adhesive. In this case, when the shaft is inserted into the rotor core, the uncured adhesive is squeezed out from the gap between the shaft 21 and the rotor core 24. The squeezed adhesive remains in the gap G, so it is possible to suppress the adhesive overflowing from the gap between the shaft 21 and the rotor core 24 from adhering to other parts, the shaft 21 other than the part constituting the gap, and other parts of the rotor core 24.

[0094] In the present embodiment, the cap 60 includes: a fixing member 5 having a cover 5b; and a fan 4 having an opposing portion 40. That is, in the cap 60 of the present embodiment, the cover 5b and the opposing portion 40 are different components from each other. The fixing member 5 is fixed to the shaft 21. On the other hand, the fan 4 is located between the fixing member 5 and the rotor core 24 in the axial direction. In addition, the fan 4 has a first hole 40h for the shaft 21 to be inserted.

[0095] The cap 60 of this embodiment can not only retain pollutants in the gap G, but also can act as a fan to send air to the inside of the rotor core 24. According to this embodiment, by making the opposing portion 40 and the cover portion 5b as separate components, the fan 4 and the fixing member 5 can be respectively formed of optimal materials. Thus, the cap 60 can be configured to store pollutants and send air through the gap G while achieving overall weight reduction.

[0096] In the present embodiment, the fixing member 5 has a second hole portion 5h through which the shaft 21 is inserted. The shaft 21 is pressed into the inner circumferential surface 5q of the second hole portion 5h. Therefore, it is not necessary to separately provide a fixing structure on the fixing member 5 and the shaft 21, and the rotor 20 can be easily manufactured. In addition, it is also possible to form a thread on the inner circumferential surface of the fixing member, and set the fixing member 5 side as an internal thread, and form a thread on the outer circumferential surface of the shaft 21, and set the shaft side as an external thread, and fix the fixing member 5 and the shaft 21 by the thread structure.

[0097] In addition, when the fixing member 5 is pressed into the shaft 21, the fixing member 5 is moved to one side in the axial direction relative to the shaft 21. The fixing member 5 is located at one side in the axial direction (+Y side) relative to the gap G. Therefore, the contaminants generated when the shaft 21 is pressed into the second hole portion 5h can be stored in the gap G. That is, the gap G of the present embodiment can not only accumulate the contaminants generated when the shaft 21 is pressed into the rotor core 24, but also accumulate the contaminants generated when the fixing member 5 is pressed into the shaft 21.

[0098] According to the present embodiment, a groove 21i is provided on the outer circumferential surface 21p of the shaft 21, which is opposite to the inner circumferential surface 5q of the second hole portion 5h. Therefore, when pressed in, a portion of the inner circumferential surface 5q of the fixing member 5 is deformed and enters the groove 21i. Thus, the shaft 21 can be prevented from moving in the circumferential direction relative to the fixing member 5.

[0099] <Modification>

[0100] Next, a rotor of a modified example that can be adopted in the above-mentioned embodiment will be described. In the description of each modified example described below, the same reference numerals are attached to the same components as those of the embodiment or modified example already described, and the description thereof will be omitted.

[0101] (Variant 1)

[0102] Figure 6 is a partial cross-sectional view of the rotor 120 of the modification example 1, showing Figure 1 FIG. 1 is a diagram of a portion corresponding to region V. Similar to the above-described embodiment, the rotor 120 of this modification includes a shaft 121, a rotor core 24, and a cap 60. The cap 60 includes a fan 4 and a fixing member 5. The shaft 121 is press-fitted into the rotor core 24 and the fixing member 5.

[0103] The shaft 121 of this modification has a first outer peripheral surface 121p, a second outer peripheral surface 121q, and an outer peripheral step surface 121t. The first outer peripheral surface 121p and the second outer peripheral surface 121q are surfaces facing radially outward. The outer peripheral step surface 121t is a surface facing one axial side (+Y side).

[0104] The first outer peripheral surface 121p is opposed to the inner peripheral surface 24q of the rotor core 24 in the radial direction. At least a portion of the first outer peripheral surface 121p is in contact with the inner peripheral surface 24q of the rotor core 24 in the radial direction.

[0105] The second outer peripheral surface 121q is located on one axial side (+Y side) of the first outer peripheral surface 121p. The outer diameter of the second outer peripheral surface 121q is smaller than the outer diameter of the first outer peripheral surface 121p. The second outer peripheral surface 121q is radially opposed to the inner peripheral surface 40q of the opposing portion 40. In addition, the second outer peripheral surface 121q is radially opposed to the inner peripheral surface 5q of the fixing member 5. At least a portion of the second outer peripheral surface 121q is in radial contact with the inner peripheral surface 5q of the fixing member 5.

[0106] The outer peripheral step surface 121t connects the first outer peripheral surface 121p and the second outer peripheral surface 121q. The outer peripheral step surface 121t extends along a plane perpendicular to the axial direction. The outer peripheral step surface 121t of this modification is configured to be on the same plane as the end surface 24f of the rotor core 24. That is, the axial position of the outer peripheral step surface 121t is consistent with the end surface 24f of the rotor core 24. In addition, the outer peripheral step surface 121t does not necessarily have to be on the same plane as the end surface 24f of the rotor core 24. That is, the axial position of the outer peripheral step surface 121t may also be different from the axial position of the end surface 24f of the rotor core 24. In addition, the outer peripheral step surface 121t does not necessarily have to be flat, and may have projections and depressions.

[0107] According to this modification, the shaft 121 has a first outer peripheral surface 121p opposed to the inner peripheral surface 24q of the rotor core 24 and a second outer peripheral surface 121q opposed to the inner peripheral surface 40q of the opposing portion 40 and having an outer diameter smaller than that of the first outer peripheral surface 121p. The gap G is surrounded by the inner peripheral surface 40q of the opposing portion 40, the end surface 24f of the rotor core, the outer peripheral step surface 121t, and the second outer peripheral surface 121q. The gap G is provided radially inside the inner peripheral surface 40q of the opposing portion 40. In the radial direction, the gap G is located between the inner peripheral surface 40q of the opposing portion 40 and the second outer peripheral surface 121q. Thus, the gap G can be ensured to be larger in the radial direction, and contaminants can be easily contained inside the gap G. In addition, the inner peripheral surface 40q can be located radially outside the inner peripheral surface 24q, or radially inside the inner peripheral surface 24q. That is, the opposing portion 40 may be in contact with only the end face 24f of the rotor core 24 in the axial direction, or may be in contact with both the end face 24f and the outer peripheral step face 121t of the rotor core 24 in the axial direction. When the opposing portion 40 is in contact with both the end face 24f and the outer peripheral step face 121t of the rotor core 24 in the axial direction, the gap G is surrounded by the outer peripheral step face 121t, the second outer peripheral face 121q, the fixing member 5, and the inner peripheral face 40q.

[0108] (Variant 2)

[0109] Figure 7 is a partial cross-sectional view of the rotor 220 of the second modification, showing Figure 1FIG. 2 is a diagram of a portion corresponding to region V of FIG. As in the above-described embodiment, the rotor 220 of this modification includes a shaft 21, a rotor core 24, and a cap 260. The cap 260 includes a fan 204 and a fixing member 5. The fan 204 includes an opposing portion 240 provided with a first hole portion 240h. In addition, the shaft 21 is press-fitted into the rotor core 24 and the fixing member 5.

[0110] The opposing portion 240 of this modification has a first inner peripheral surface 240p, a second inner peripheral surface 240q, and an inner peripheral step surface 240t as the inner peripheral surface of the first hole portion 240h. The first inner peripheral surface 240p and the second inner peripheral surface 240q are surfaces facing radially inward. The inner peripheral step surface 240t is a surface facing the other axial side (-Y side).

[0111] The gap G is located between the outer peripheral surface 21p of the shaft 21 and the opposing portion 240 in the radial direction. That is, the gap G is located between the first inner peripheral surface 240p and the second inner peripheral surface 240q in the radial direction. The first inner peripheral surface 240p and the second inner peripheral surface 240q are opposed to the outer peripheral surface 21p of the shaft 21 in the radial direction with the gap G therebetween. The second inner peripheral surface 240q is located on one side (+Y side) of the axial direction than the first inner peripheral surface 240p. The inner diameter of the second inner peripheral surface 240q is smaller than the inner diameter of the first inner peripheral surface 240p. The inner peripheral step surface 240t connects the first inner peripheral surface 240p and the second inner peripheral surface 240q. The inner peripheral step surface 240t extends along a plane perpendicular to the axial direction. The gap G is located between the inner peripheral step surface 240t and the end surface 24f of the rotor core 24 in the axial direction. In addition, the inner peripheral step surface 240t only needs to extend along a plane perpendicular to the axial direction, and may be flat or have projections and depressions.

[0112] According to this modification, the inner diameter of the first inner peripheral surface 240p of the opposing portion 240 located on the rotor core 24 side in the axial direction is larger than the inner diameter of the second inner peripheral surface 240q located on the opposite side of the rotor core 24. Therefore, the gap G provided between the opposing portion 240 and the shaft 21 in the radial direction becomes larger on the rotor core 24 side in the axial direction. As a result, the gap G provided on the radial inner side of the opposing portion 240 can be ensured to be larger in the radial direction, and contaminants can be easily contained in the gap G. In addition, in this modification, the second inner peripheral surface 240q may also be in contact with the outer peripheral surface 21p of the shaft 21. That is, the gap G can be surrounded by the first outer circumferential surface 21p, the fixing part 5, the second inner circumferential surface 240q, the inner circumferential step surface 240t, the first inner circumferential surface 240p and the end surface 24f of the rotor core, or it can be surrounded by the first outer circumferential surface 21p, the fixing part 5, the inner circumferential step surface 240t, the first inner circumferential surface 240p and the end surface 24f of the rotor core.

[0113] (Variant 3)

[0114] Figure 8is a partial cross-sectional view of the rotor 320 of the modification example 3, showing Figure 1 The region V corresponds to the portion of the diagram.

[0115] The rotor 320 of this modification has a structure obtained by combining the above-mentioned modification 1 and modification 2. The shaft 121 of this modification has the same structure as that of modification 1. In addition, the cap 260 of this modification has the same structure as that of modification 2.

[0116] The rotor 320 of this modification example includes the shaft 121, the rotor core 24, and the cap 260. The cap 260 includes the fan 204 and the fixing member 5. The shaft 121 is press-fitted into the rotor core 24 and the fixing member 5.

[0117] That is, the shaft 121 of this modification has a first outer peripheral surface 121p, a second outer peripheral surface 121q, and an outer peripheral step surface 121t. The first outer peripheral surface 121p is opposed to the inner peripheral surface 24q of the rotor core 24. The second outer peripheral surface 121q is located at a position closer to the axial side (+Y side) than the first outer peripheral surface 121p. The outer diameter of the second outer peripheral surface 121q is smaller than the outer diameter of the first outer peripheral surface 121p. The outer peripheral step surface 121t connects the first outer peripheral surface 121p and the second outer peripheral surface 121q. In addition, the opposing portion 240 of this modification has a first inner peripheral surface 240p, a second inner peripheral surface 240q, and an inner peripheral step surface 240t. The second inner peripheral surface 240q is located at a position closer to the axial side (+Y side) than the first inner peripheral surface 240p. The inner diameter of the second inner peripheral surface 240q is smaller than the inner diameter of the first inner peripheral surface 240p. The inner peripheral step surface 240t connects the first inner peripheral surface 240p and the second inner peripheral surface 240q. In addition, the second outer peripheral surface 121q and the first inner peripheral surface 240p are radially opposed to each other with a gap G therebetween. The gap G is radially located between the opposing portion 240 and the second outer peripheral surface 121q. That is, the gap G is radially located between the first inner peripheral surface 240p and the second inner peripheral surface 240q and the second outer peripheral surface 121q.

[0118] According to this modification, a large gap G can be ensured in the radial direction between the second outer peripheral surface 121q having a smaller outer diameter than other parts and the first inner peripheral surface 240p having a larger inner diameter than other parts, and contaminants can be easily contained in the gap G. In addition, in this modification, the second inner peripheral surface 240q may also be in contact with the second outer peripheral surface 121q of the shaft 121. The gap G may be surrounded by the second outer peripheral surface 121q, the fixing member 5, the second inner peripheral surface 240q, the inner peripheral step surface 240t, the first inner peripheral surface 240p, the end surface 24f of the rotor core 24, and the outer peripheral step surface 121t, or may be surrounded by the second outer peripheral surface 121q, the fixing member 5, the inner peripheral step surface 240t, the first inner peripheral surface 240p, the end surface 24f of the rotor core 24, and the outer peripheral step surface 121t. The outer peripheral step surface 121t does not necessarily have to be flush with the end surface 24f of the rotor core 24. That is, the axial position of the outer peripheral step surface 121t may be different from the axial position of the end surface 24f of the rotor core 24. The inner peripheral step surface 240t may be axially opposed to both the end surface 24f of the rotor core 24 and the outer peripheral step surface 121t, or may be opposed only to the end surface 24f of the rotor core 24. In other words, as long as the inner peripheral step surface 240t is formed, the first inner peripheral surface 240p may be radially outward or radially inward relative to the first outer peripheral surface 121p. As long as the inner peripheral step surface 240t is formed, the opposing portion 240 may be in contact with both the end surface 24f of the rotor core 24 and the outer peripheral step surface 121t, or may be in contact with only the end surface 24f of the rotor core 24.

[0119] (Variant 4)

[0120] Fig. 9 is a partial cross-sectional view of a rotor 420 of Modification 4, showing Figure 1 FIG. 4 is a diagram of a portion corresponding to region V of FIG. Similar to the above-mentioned embodiment, the rotor 420 of this modification has a shaft 21, a rotor core 24, and a cap 460. The cap 460 of this modification is composed of a single component. That is, in this modification, the fan and the fixing component of the cap 460 are formed as one component. In addition, as long as the gap G can be formed, the cap 460 may have only a fixing component without a fan. The shaft 21 is pressed into the rotor core 24 and the cap 460.

[0121] The cap 460 is annular. The cap 460 includes an opposing portion 440 and a cover portion 405b. The opposing portion 440 and the cover portion 405b are arranged side by side in the axial direction. The opposing portion 440 and the cover portion 405b are both annular.

[0122] The opposing portion 440 has an inner circumferential surface 440q facing radially inward. The inner circumferential surface 440q surrounds the shaft 21 from the radially outer side. The inner circumferential surface 440q is radially opposed to the outer circumferential surface 21p of the shaft 21. The opposing portion 440 is in contact with the end surface 24f of the rotor core 24 in the axial direction. A gap G is provided between the inner circumferential surface 440q of the opposing portion 440 and the outer circumferential surface 21p of the shaft 21.

[0123] The cover portion 405b is located on one axial side (+Y) of the opposing portion 440. The inner circumferential surface 405q of the cover portion 405b contacts the outer circumferential surface 21p of the shaft 21 in the radial direction. The cover portion 405b covers the gap G from one axial side (+Y). More specifically, the inner circumferential step surface connecting the inner circumferential surface 440q of the opposing portion 440 and the inner circumferential surface 405q of the cover portion 405b is axially opposed to the end surface 24f of the rotor core 24. The gap G is covered from one axial side (+Y side) by the inner circumferential step surface.

[0124] According to this modification, similarly to the above-described embodiment, contaminants generated when the shaft 21 is pressed into the rotor core 24 and when the shaft 21 is pressed into the cap 460 are easily contained in the gap G. In addition, according to this modification, the cap 460 can be formed of a single component. Therefore, the number of components of the rotor 420 can be reduced.

[0125] (Variant 5)

[0126] Fig.10 is a partial cross-sectional view of a rotor 520 of Modification 5, showing Figure 1 FIG. 5 is a diagram of a portion corresponding to region V of FIG. 5. As in the above-described embodiment, the rotor 520 of this modification includes a shaft 521, a rotor core 24, and a cap 560. The cap 560 of this modification includes an opposing portion 540 and a cover 505b. The cover 505b is a portion of the shaft 521. In addition, the shaft 521 is pressed into the rotor core 24.

[0127] The opposing portion 540 has an inner circumferential surface 540q facing radially inward. The inner circumferential surface 540q surrounds the shaft 521 from the radially outer side. The inner circumferential surface 540q is radially opposed to the outer circumferential surface 521p of the shaft 21. The opposing portion 540 is in contact with the end surface 24f of the rotor core 24 in the axial direction. A gap G is provided between the inner circumferential surface 540q of the opposing portion 540 and the outer circumferential surface 521p of the shaft 521.

[0128] The cover portion 505b protrudes radially outward from the outer peripheral surface 521p of the shaft 521. In this modified example, the cover portion 505b extends in a circular ring shape along the circumferential direction. The cover portion 505b is located on one axial side (+Y) of the opposing portion 540. The cover portion 505b overlaps with at least a portion of the opposing portion 540 on one axial side (+Y). Preferably, the cover portion 505b is in contact with at least a portion of the opposing portion 540 on one axial side (+Y). The cover portion 505b is axially opposed to the end face 24f of the rotor core 24. The cover portion 505b covers the gap G from one axial side (+Y). In addition, the cover portion 505b does not necessarily have to be annular, as long as it extends along the circumferential direction.

[0129] According to this modification, similarly to the above-described embodiment, contaminants generated when the shaft 521 is pressed into the rotor core 24 are easily contained in the gap G. In addition, according to this modification, by providing the cover portion 505b as a part of the cap portion 560 on the outer peripheral surface 521p of the shaft 521, the number of parts of the rotor 520 can be reduced.

[0130] (Variant 6)

[0131] Fig.11 1 is a schematic cross-sectional view of the facing portion 640 of the cap portion 660 and the shaft 21 according to Modification 6. This modification is different from the above-described embodiment in that the gaps G are discretely arranged along the circumferential direction.

[0132] In this modification, a plurality of (four in this modification) first recesses 640e are provided on the inner circumferential surface 640q of the opposing portion 640. The plurality of first recesses 640e are arranged at equal intervals along the circumferential direction. The inner circumferential surface 640q of the opposing portion 640 contacts the outer circumferential surface 21p of the shaft 21 at a portion other than the first recesses 640e. Therefore, in this modification, a plurality of gaps G arranged along the circumferential direction are provided between the inner circumferential surface 640q of the opposing portion 640 and the outer circumferential surface 21p of the shaft 21. In this modification, the circumferential width, radial width, and axial width of the plurality of gaps G are respectively equal.

[0133] In this modification, a plurality of (four in this modification) second recesses 624e arranged in the circumferential direction and a press-in portion 624d located between the second recesses 624e adjacent in the circumferential direction are provided on the inner circumferential surface 624q of the rotor core 624. In this modification, the second recesses 624e and the press-in portions 624d are alternately arranged in the circumferential direction. The inner circumferential surface 640q of the opposing portion 640 is pressed into the shaft 21 in the press-in portion 624d. When viewed from the axial direction, the press-in portion 624d overlaps with the gap G. According to this modification, contaminants generated in the plurality of press-in portions 624d discretely arranged in the circumferential direction can be contained in the gap G.

[0134] In this modification, the case where the gap G is provided between the inner circumferential surface 640q of the opposing portion 640 and the outer circumferential surface 21p of the shaft 21 by providing the first recessed portion 640e on the inner circumferential surface 640q of the opposing portion 640 is described. However, the gap G may be provided by providing a recessed portion on the portion of the outer circumferential surface 21p of the shaft 21 that is opposed to the opposing portion. In addition, in this modification, the circumferential width, radial width, and axial width of the plurality of gaps G may all be different for each gap G, or may include a case where at least one width is the same. In addition, the plurality of gaps G shown in this modification may also be combined with other modifications.

[0135] The various embodiments and modifications of the present invention have been described above, but each structure and combination thereof in each embodiment and modification is an example, and addition, omission, substitution and other changes of the structure can be made without departing from the scope of the gist of the present invention. In addition, the present invention is not limited by the embodiments.

[0136] For example, in the above-mentioned embodiment, the coil is a bendable wire mounted on the stator, and the lead wire extending from the coil has a structure formed by bundling a plurality of wires using a crimping terminal. However, the coil may also be a segmented coil composed of a highly rigid flat wire, and the lead wire extending from the coil is also a single flat wire.

[0137] In addition, the present technology can adopt the following structures.

[0138] (1) A rotor capable of rotating around a central axis, wherein the rotor comprises: a shaft extending along the central axis; a rotor core in an annular shape for inserting the shaft; and a cap portion located on one axial side of the rotor core and provided on the shaft, the cap portion comprising: an opposing portion surrounding the shaft from the radially outer side and contacting an end surface of the rotor core facing the axial side; and a cover portion located on one axial side of the opposing portion, a gap being provided between an inner circumferential surface of the opposing portion and an outer circumferential surface of the shaft, the cover portion covering the gap from one axial side.

[0139] (2) The rotor according to (1), wherein the shaft is press-fitted into the inner peripheral surface of the rotor core.

[0140] (3) The rotor according to (2), wherein a groove is provided on a portion of the outer peripheral surface of the shaft that faces the inner peripheral surface of the rotor core.

[0141] (4) A rotor according to any one of (1) to (3), wherein the cap portion comprises: a fixing member fixed to the shaft; and an opposing member located axially between the fixing member and the rotor core and having a first hole portion through which the shaft is inserted, the opposing member having the opposing portion, and the fixing member having the cover portion.

[0142] (5) A rotor according to (4), wherein the fixing member has a second hole portion through which the shaft is inserted, the shaft is pressed into the inner circumferential surface of the second hole portion, and a groove portion is provided on the outer circumferential surface of the shaft and opposite to the inner circumferential surface of the second hole portion.

[0143] (6) A rotor according to (4) or (5), wherein the fixing component comprises: a cylindrical portion which is cylindrical with the central axis as its center; and a cover portion which protrudes radially outward from an end portion on the other axial side of the cylindrical portion and extends in the circumferential direction.

[0144] (7) A rotor according to any one of (1) to (6), wherein the shaft has: a first outer peripheral surface which is opposite to the inner peripheral surface of the rotor core; a second outer peripheral surface which is opposite to the inner peripheral surface of the opposing portion, the outer diameter of the second outer peripheral surface being smaller than the outer diameter of the first outer peripheral surface; and an outer peripheral step surface which connects the first outer peripheral surface and the second outer peripheral surface.

[0145] (8) A rotor according to any one of (1) to (6), wherein the opposing portion comprises: a first inner circumferential surface; a second inner circumferential surface located axially closer to the first inner circumferential surface, the inner diameter of the second inner circumferential surface being smaller than the inner diameter of the first inner circumferential surface; and an inner circumferential step surface connecting the first inner circumferential surface and the second inner circumferential surface.

[0146] (9) A rotor according to any one of (1) to (6), wherein the shaft comprises: a first outer peripheral surface which is opposite to the inner peripheral surface of the rotor core; a second outer peripheral surface which is located axially closer to the first outer peripheral surface, the outer diameter of the second outer peripheral surface being smaller than the outer diameter of the first outer peripheral surface; and an outer peripheral step surface which connects the first outer peripheral surface and the second outer peripheral surface, and the opposing portion comprises: a first inner peripheral surface; a second inner peripheral surface which is located axially closer to the first inner peripheral surface, the inner diameter of the second inner peripheral surface being smaller than the inner diameter of the first inner peripheral surface; and an inner peripheral step surface which connects the first inner peripheral surface and the second inner peripheral surface, the second outer peripheral surface being radially opposite to the first inner peripheral surface with the gap therebetween.

[0147] (10) The rotor according to any one of (1) to (9), wherein the gap extends in an annular shape along the circumferential direction.

[0148] (11) The rotor according to any one of (1) to (9), wherein a plurality of the gaps arranged in the circumferential direction are provided between the inner peripheral surface of the opposing portion and the outer peripheral surface of the shaft.

[0149] (12) A rotor according to any one of (1) to (11), wherein the shaft has a recessed portion open at any end in the axial direction, the recessed portion is for inserting an end of another shaft, and the recessed portion is arranged at a position different from the rotor core in the axial direction.

[0150] (13) A rotor according to any one of (1) to (12), wherein the rotor core has an air vent extending axially therethrough, the opposing portion has a through hole connected to the air vent, the through hole extending axially therethrough, and the cover portion is disposed at a position different from the through hole when viewed axially.

[0151] (14) A rotating electrical machine comprising: the rotor according to any one of (1) to (13); and a stator surrounding the rotor from the radially outer side.

[0152] (15) A drive device comprising: the rotating electric machine described in (14); and a power transmission mechanism that transmits the power of the rotating electric machine.

Claims

1. A rotor capable of rotating about a central axis, wherein: The rotor has: a shaft extending along a central axis; a rotor core in a ring shape for the shaft to be inserted into; and A cap portion, which is located on one axial side of the rotor core and is arranged on the shaft, The cap portion has: an opposing portion that surrounds the shaft from the radially outer side and contacts an end surface of the rotor core that faces one axial side; and a cover portion, which is located on one axial side of the opposing portion, A gap is provided between the inner peripheral surface of the opposing portion and the outer peripheral surface of the shaft, The cover portion covers the gap from one axial side.

2. The rotor according to claim 1, wherein: The shaft is press-fitted into the inner circumferential surface of the rotor core.

3. The rotor according to claim 2, wherein: A groove portion is provided on a portion of the outer peripheral surface of the shaft that faces the inner peripheral surface of the rotor core.

4. The rotor according to claim 1, wherein: The cap portion has: a fixing member fixed to the shaft; and an opposing member, which is located between the fixing member and the rotor core in the axial direction and has a first hole portion through which the shaft is inserted, The opposing member has the opposing portion, The fixing member includes the cover portion.

5. The rotor according to claim 4, wherein: The fixing member has a second hole portion through which the shaft is inserted. The shaft is pressed into the inner peripheral surface of the second hole portion. A groove portion is provided on a portion of the outer peripheral surface of the shaft that faces the inner peripheral surface of the second hole portion.

6. The rotor according to claim 4, wherein: The fixing member has: a cylindrical portion having a cylindrical shape centered on the central axis; and The cover portion protrudes radially outward from the other axial end of the cylindrical portion and extends in the circumferential direction.

7. The rotor according to claim 1, wherein: The shaft has: a first outer peripheral surface, which is opposite to the inner peripheral surface of the rotor core; a second outer peripheral surface facing the inner peripheral surface of the opposing portion, the outer diameter of the second outer peripheral surface being smaller than the outer diameter of the first outer peripheral surface; and An outer peripheral step surface connects the first outer peripheral surface and the second outer peripheral surface.

8. The rotor according to claim 1, wherein: The opposing portion has: 1st inner peripheral surface; a second inner peripheral surface located axially closer to one side than the first inner peripheral surface, the inner diameter of the second inner peripheral surface being smaller than the inner diameter of the first inner peripheral surface; and An inner peripheral step surface connects the first inner peripheral surface and the second inner peripheral surface.

9. The rotor according to claim 1, wherein: The shaft has: a first outer peripheral surface, which is opposite to the inner peripheral surface of the rotor core; a second outer peripheral surface located axially closer to one side than the first outer peripheral surface, the outer diameter of the second outer peripheral surface being smaller than the outer diameter of the first outer peripheral surface; and an outer peripheral step surface connecting the first outer peripheral surface and the second outer peripheral surface, The opposing portion has: 1st inner peripheral surface; a second inner peripheral surface, which is located axially closer to one side than the first inner peripheral surface, and has an inner diameter smaller than that of the first inner peripheral surface; as well as an inner peripheral step surface connecting the first inner peripheral surface and the second inner peripheral surface, The second outer peripheral surface and the first inner peripheral surface are opposed to each other in the radial direction with the gap interposed therebetween.

10. The rotor according to any one of claims 1 to 9, wherein: The gap extends in an annular shape along the circumferential direction.

11. The rotor according to any one of claims 1 to 9, wherein: A plurality of the gaps are provided between the inner peripheral surface of the facing portion and the outer peripheral surface of the shaft so as to be arranged in the circumferential direction.

12. The rotor according to claim 1, wherein: The shaft has a recessed portion opened at any end in the axial direction, and the end of the other shaft is inserted into the recessed portion. The recessed portion is arranged at a position different from that of the rotor core in the axial direction.

13. The rotor according to claim 1, wherein: The rotor core has an air hole extending through the rotor core in the axial direction. The opposing portion has a through hole connected to the vent hole, the through hole penetrates the opposing portion in the axial direction, and the cover portion is provided at a position different from the through hole when viewed in the axial direction.

14. A rotating electrical machine, comprising: The rotor of claim 1; and A stator surrounds the rotor from the radial outside.

15. A driving device, comprising: The rotating electrical machine according to claim 14; and A power transmission mechanism transmits the power of the rotating electric machine.

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