WO2024111584A1

WO2024111584A1 - Centrifugal compressor

Info

Publication number: WO2024111584A1
Application number: PCT/JP2023/041824
Authority: WO
Inventors: 英文森; 花帆竹内; 亮楳山
Original assignee: 株式会社豊田自動織機
Priority date: 2022-11-25
Filing date: 2023-11-21
Publication date: 2024-05-30
Also published as: JP2024076672A

Abstract

This centrifugal compressor (10) comprises a rotating body (60) and a motor (31). The motor (31) comprises a rotor (33) having a cylindrical member (41). The rotating body (60) has an axial path (63) and a plurality of paths (71, 90). The centrifugal compressor (10) comprises a first member (61) having a shroud surface (67, 83), a second member (62) having a hub surface (68), and a plurality of impellers (69, 80) extending from one among the shroud surface (67, 83) and the hub surface (68) to the other. The plurality of impellers (69, 80) are provided to one among the first member (61) and the second member (62). The cylindrical member (41) has the first member (61) and the second member (62) therein, forms a portion of each path (71), and opens into a motor compartment (18).

Description

Centrifugal Compressor

This disclosure relates to centrifugal compressors.

The centrifugal compressor has a rotating body including a rotating shaft and an impeller. The impeller rotates integrally with the rotating shaft. The impeller compresses air. The centrifugal compressor has a motor and a housing. The motor rotates the rotating shaft. The housing has an impeller chamber, a motor chamber, and an intake port. The impeller chamber houses the impeller. The motor chamber houses the motor. The intake port draws air into the impeller chamber.

The motor includes a stator and a rotor. The stator is fixed to a housing. The rotor rotates integrally with the rotating shaft. The rotor is disposed inside the stator. The rotor constitutes a part of a rotating body. The rotor includes a cylindrical member and a magnetic body. The magnetic body is fixed to the inside of the cylindrical member. The rotating shaft may include a first shaft member and a second shaft member. The first shaft member and the second shaft member are provided on both sides of the magnetic body in the axial direction of the cylindrical member. The impeller is connected to the first shaft member, for example.

In such a centrifugal compressor, it is desirable to cool the motor. For example, as in Patent Document 1, a centrifugal compressor may have an axial passage and multiple radial passages. The axial passage opens at one end of the first shaft member to which the impeller is connected and communicates with the suction port. The axial passage extends inside the first shaft member in the axial direction of the rotating shaft. The multiple radial passages extend inside the rotor in the radial direction of the rotating shaft and communicate with the motor chamber. The multiple radial passages introduce air from the axial passage into the motor chamber. The motor is then cooled by the air introduced into the motor chamber from the suction port via the axial passage and each of the radial passages.

Patent No. 6968253

Incidentally, each passage may be formed from a shroud surface that defines each passage, a hub surface that extends along the shroud surface and defines each passage, and a number of vanes that extend from one of the shroud surface and the hub surface to the other. When multiple passages with such a configuration are used, the air flowing through each passage is more likely to be accelerated by the centrifugal force that accompanies the rotation of the rotor, and air can be efficiently introduced from each passage into the motor chamber. As a result, the motor is efficiently cooled. However, when such multiple passages are formed inside a rotating shaft, for example, the rotating shaft is manufactured using a mold with a complex structure, which may increase manufacturing costs.

A centrifugal compressor according to one embodiment comprises a rotor including a rotating shaft and an impeller configured to rotate integrally with the rotating shaft to compress air, a motor configured to rotate the rotating shaft, and a housing having an impeller chamber that accommodates the impeller, a motor chamber that accommodates the motor, and an intake port that draws air into the impeller chamber, the motor comprises a stator fixed to the housing, and a rotor configured to rotate integrally with the rotating shaft and disposed inside the stator, constituting a part of the rotor, the rotor having a tubular member and a magnetic body fixed to the inside of the tubular member, the rotating shaft includes a first shaft member and a second shaft member provided on both sides of the magnetic body in the axial direction of the tubular member, the impeller is connected to the first shaft member, and the rotor has an opening at one end of the first shaft member to which the impeller is connected, forming the intake port. A centrifugal compressor that includes an axial passage that extends through the inside of the first shaft member in the axial direction of the rotating shaft and communicates with the inside of the rotor in the radial direction of the rotating shaft, and a plurality of paths that connect the inside of the rotor to the motor chamber and introduce air from the axial passage into the motor chamber, and the motor is cooled by air introduced into the motor chamber from the suction port through the axial passage and each of the paths, and includes a first member having a shroud surface that defines a portion of each of the paths, a second member having a hub surface that extends along the shroud surface and defines a portion of each of the paths, and a plurality of blades that extend from one of the shroud surface and the hub surface to the other and define a portion of each of the paths, the plurality of blades being provided on one of the first member and the second member, and the cylindrical member has the first member and the second member inside, forms a portion of each of the paths, and opens into the motor chamber.

1 is a cross-sectional view of a centrifugal compressor according to a first embodiment. FIG. FIG. 2 is an enlarged cross-sectional view showing a portion of the centrifugal compressor of FIG. 1 . FIG. 2 is an enlarged cross-sectional view showing a portion of the centrifugal compressor of FIG. 1 . FIG. 2 is an enlarged cross-sectional view showing a portion of the centrifugal compressor of FIG. 1 . FIG. 2 is an enlarged cross-sectional view showing a portion of the centrifugal compressor of FIG. 1. FIG. 5 is a cross-sectional view of a centrifugal compressor according to a second embodiment. FIG. 7 is an enlarged cross-sectional view of a portion of the centrifugal compressor of FIG. 6.

[First embodiment]
A centrifugal compressor according to a first embodiment will be described below with reference to Fig. 1 to Fig. 5. The centrifugal compressor of this embodiment is mounted on a fuel cell vehicle. The centrifugal compressor is configured to compress air.

<Basic configuration of centrifugal compressor 10>
As shown in Fig. 1, the centrifugal compressor 10 includes a housing 11. The housing 11 is made of a metal material. For example, the housing 11 is made of aluminum. The housing 11 is cylindrical. The housing 11 includes a motor housing 12, a compressor housing 13, a turbine housing 14, a first plate 15, a second plate 16, and a seal plate 17.

The motor housing 12 is cylindrical. The motor housing 12 has a plate-shaped end wall 12a and a peripheral wall 12b. The peripheral wall 12b extends cylindrically from the outer periphery of the end wall 12a. The first plate 15 is connected to the open end of the peripheral wall 12b of the motor housing 12. The first plate 15 closes the opening of the peripheral wall 12b of the motor housing 12. The end wall 12a and peripheral wall 12b of the motor housing 12 and the first plate 15 define a motor chamber 18. Thus, the housing 11 has a motor chamber 18.

As shown in FIG. 2, the first plate 15 has a first recess 15c and a second recess 15d. The first recess 15c and the second recess 15d are formed on the end face 15a of the first plate 15 opposite the motor housing 12. The first recess 15c and the second recess 15d are circular holes. The inner diameter of the first recess 15c is larger than the inner diameter of the second recess 15d. The second recess 15d is formed on the bottom face 15f of the first recess 15c. The axis of the first recess 15c and the axis of the second recess 15d are aligned.

The seal plate 17 is fitted into the first recess 15c. The seal plate 17 is attached to the first plate 15, for example, by bolts (not shown). The seal plate 17 closes the opening of the second recess 15d. The seal plate 17 and the second recess 15d define a thrust bearing accommodating chamber 19. Therefore, the housing 11 has the thrust bearing accommodating chamber 19. The seal plate 17 also has a shaft insertion hole 17h. The shaft insertion hole 17h is formed in the center of the seal plate 17. The shaft insertion hole 17h opens into the thrust bearing accommodating chamber 19.

The first plate 15 has a first radial bearing retaining portion 21. The first radial bearing retaining portion 21 is cylindrical. The first radial bearing retaining portion 21 protrudes into the motor chamber 18 from the center of the end face 15b of the first plate 15 on the motor housing 12 side. The first radial bearing retaining portion 21 is connected to the motor chamber 18. The first radial bearing retaining portion 21 penetrates the first plate 15 and opens to the bottom surface 15h of the second recess 15d. Therefore, the first radial bearing retaining portion 21 is connected to the thrust bearing accommodating chamber 19. The axis of the first radial bearing retaining portion 21 coincides with the axis of the first recess 15c and the axis of the second recess 15d.

The compressor housing 13 is cylindrical. The compressor housing 13 has a circular suction port 22. Therefore, the housing 11 has the suction port 22. The compressor housing 13 is connected to the end face 15a of the first plate 15 with the axis of the suction port 22 coinciding with the axis of the shaft insertion hole 17h of the seal plate 17. The suction port 22 opens into the end face of the compressor housing 13 opposite the first plate 15.

Between the compressor housing 13 and the seal plate 17, an impeller chamber 23, a discharge chamber 24, and a compressor diffuser passage 25 are formed. Thus, the housing 11 has the impeller chamber 23. The seal plate 17 separates the impeller chamber 23 from the thrust bearing accommodating chamber 19. The impeller chamber 23 is connected to the suction port 22. The impeller chamber 23 is in the shape of a generally truncated cone hole whose diameter gradually increases as it moves away from the suction port 22. The discharge chamber 24 extends around the axis of the suction port 22 around the impeller chamber 23. The compressor diffuser passage 25 connects the impeller chamber 23 and the discharge chamber 24. The impeller chamber 23 is connected to the shaft insertion hole 17h of the seal plate 17.

As shown in FIG. 3, the motor housing 12 has a second radial bearing retaining portion 26. The second radial bearing retaining portion 26 is cylindrical. The second radial bearing retaining portion 26 protrudes from the center of the inner surface of the end wall 12a of the motor housing 12 into the motor chamber 18. The second radial bearing retaining portion 26 is connected to the motor chamber 18. The inner side of the second radial bearing retaining portion 26 penetrates the end wall 12a of the motor housing 12 and opens to the outer surface of the end wall 12a. The axis of the first radial bearing retaining portion 21 and the axis of the second radial bearing retaining portion 26 are aligned.

The second plate 16 is connected to the outer surface of the end wall 12a of the motor housing 12. The second plate 16 has a shaft insertion hole 16h. The shaft insertion hole 16h is formed in the center of the second plate 16.

The turbine housing 14 is cylindrical. The turbine housing 14 has a circular discharge port 27. The turbine housing 14 is connected to the end face 16a of the second plate 16 opposite the motor housing 12, with the axis of the discharge port 27 coinciding with the axis of the shaft insertion hole 16h of the second plate 16. The discharge port 27 opens into the end face of the turbine housing 14 opposite the second plate 16.

Between the turbine housing 14 and the end face 16a of the second plate 16, a turbine chamber 28, a turbine scroll passage 29, and a communication passage 30 are formed. The turbine chamber 28 is connected to the discharge port 27. The turbine scroll passage 29 extends around the axis of the discharge port 27 around the turbine chamber 28. The communication passage 30 connects the turbine chamber 28 and the turbine scroll passage 29. The turbine chamber 28 is connected to the shaft insertion hole 16h of the second plate 16.

As shown in FIG. 1, the centrifugal compressor 10 is equipped with a motor 31. The motor 31 is housed in the motor chamber 18. Therefore, the motor chamber 18 houses the motor 31. And the motor 31 is housed in the housing 11.

The motor 31 includes a stator 32 and a rotor 33. The stator 32 includes a cylindrical stator core 34 and a coil 35. The coil 35 is wound around the stator core 34. The stator core 34 is fixed to the inner circumferential surface of the peripheral wall 12b of the motor housing 12. Thus, the stator 32 is fixed to the housing 11. Coil ends 36, which are part of the coil 35, protrude from both end surfaces of the stator core 34. In the following description, of the two coil ends 36, the coil end 36 located near the first plate 15 in the stator core 34 is referred to as the "first coil end 36a." Also, of the two coil ends 36, the coil end 36 located near the end wall 12a of the motor housing 12 in the stator core 34 is referred to as the "second coil end 36b."

As shown in FIG. 4, the stator 32 includes a resin part 37. The resin part 37 covers the stator core 34 and the coil end 36. The resin part 37 includes a first resin part 38, a second resin part 39, and a third resin part 40. Thus, the stator 32 includes the first resin part 38, the second resin part 39, and the third resin part 40. The first resin part 38 is cylindrical and covers the first coil end 36a with resin. The second resin part 39 is cylindrical and covers the second coil end 36b with resin. The third resin part 40 is cylindrical and covers the inner circumferential surface of the stator core 34 with resin. The third resin part 40 extends in the axial direction of the stator core 34 inside the stator core 34. The third resin part 40 connects the first resin part 38 and the second resin part 39.

The rotor 33 is disposed inside the stator 32. The rotor 33 has a cylindrical member 41 and a permanent magnet 42, which is a magnetic body. The cylindrical member 41 is made of, for example, a titanium alloy. The cylindrical member 41 is cylindrical in shape with the axis of the cylindrical member 41 extending linearly. The outer diameter of the cylindrical member 41 is constant.

The permanent magnet 42 is cylindrical. The permanent magnet 42 is disposed inside the tubular member 41. The axis of the permanent magnet 42 coincides with the axis of the tubular member 41. The permanent magnet 42 is press-fitted into the inner circumferential surface of the tubular member 41. Therefore, the permanent magnet 42 is fixed inside the tubular member 41. The permanent magnet 42 is magnetized in the radial direction of the permanent magnet 42. Specifically, the permanent magnet 42 is magnetized in the radial direction of the permanent magnet 42, so that the permanent magnet 42 is cylindrical with a north pole and a south pole on both radial sides of the permanent magnet 42.

The length of the permanent magnet 42 in the axial direction is shorter than the length of the tubular member 41 in the axial direction. Both end faces of the permanent magnet 42 are located inside the tubular member 41. Therefore, both end portions located in the axial direction of the tubular member 41 protrude in the axial direction relative to both end faces of the permanent magnet 42. And both end portions of the tubular member 41 protrude in the axial direction relative to both end faces of the stator core 34.

As shown in FIG. 1, the centrifugal compressor 10 has a rotating shaft 43. The rotating shaft 43 includes a first shaft member 44 and a second shaft member 45. The first shaft member 44 and the second shaft member 45 are provided on both sides of the permanent magnet 42 in the axial direction of the cylindrical member 41. The first shaft member 44 and the second shaft member 45 are made of, for example, iron.

The first end of the first shaft member 44 is fixed to the first end of the tubular member 41. The first shaft member 44 protrudes from the motor chamber 18 into the impeller chamber 23, passing through the inside of the first radial bearing holder 21, the thrust bearing accommodating chamber 19, and the shaft insertion hole 17h. The first end of the second shaft member 45 is press-fitted into the inner circumferential surface of the second end of the tubular member 41. Therefore, the second shaft member 45 is fixed to the tubular member 41. The second end of the second shaft member 45 protrudes from the motor chamber 18 into the turbine chamber 28, passing through the inside of the second radial bearing holder 26 and the shaft insertion hole 16h.

The centrifugal compressor 10 includes a first seal member 46. The first seal member 46 is provided between the shaft insertion hole 17h of the seal plate 17 and the first shaft member 44. The first seal member 46 prevents air from leaking from the impeller chamber 23 toward the motor chamber 18. The centrifugal compressor 10 includes a second seal member 47. The second seal member 47 is provided between the shaft insertion hole 16h of the second plate 16 and the second shaft member 45. The second seal member 47 prevents air from leaking from the turbine chamber 28 toward the motor chamber 18. The first seal member 46 and the second seal member 47 are, for example, seal rings.

The centrifugal compressor 10 is provided with a support portion 48. The support portion 48 protrudes in an annular shape from the outer peripheral surface of the first shaft member 44. The support portion 48 is disk-shaped. The support portion 48 is fixed to the outer peripheral surface of the first shaft member 44 in a state in which it protrudes in an annular shape radially outward from the outer peripheral surface of the first shaft member 44. Therefore, the support portion 48 is separate from the first shaft member 44. The support portion 48 is disposed in the thrust bearing housing chamber 19. The support portion 48 rotates integrally with the first shaft member 44.

The centrifugal compressor 10 includes an impeller 49. The impeller 49 is attached to the second end of the first shaft member 44. Therefore, the impeller 49 is connected to the first shaft member 44. The impeller 49 is disposed closer to the second end of the first shaft member 44 than the support portion 48 of the first shaft member 44. The impeller 49 is cylindrical and gradually reduces in diameter from the back surface to the tip surface. The impeller 49 is housed in the impeller chamber 23. Therefore, the impeller chamber 23 houses the impeller 49. The outer edge of the impeller 49 extends along the inner peripheral surface of the impeller chamber 23. The impeller 49 compresses air by rotating integrally with the first shaft member 44. Therefore, the impeller 49 compresses air by rotating integrally with the rotating shaft 43.

The rotating shaft 43 and the impeller 49 constitute the rotating body 60. Therefore, the rotating body 60 includes the rotating shaft 43 and the impeller 49. The rotor 33 rotates integrally with the first shaft member 44 and the second shaft member 45. Therefore, the rotor 33 rotates integrally with the rotating shaft 43. The rotor 33 constitutes a part of the rotating body 60. The motor 31 rotates the rotating shaft 43.

The centrifugal compressor 10 includes a turbine wheel 50. The turbine wheel 50 is attached to the second end of the second shaft member 45. The turbine wheel 50 is housed in the turbine chamber 28. The turbine wheel 50 rotates integrally with the second shaft member 45.

The centrifugal compressor 10 includes a first radial bearing 51 and a second radial bearing 52. The first radial bearing 51 is cylindrical. The first radial bearing 51 is held by the first radial bearing holder 21. Therefore, the first radial bearing holder 21 holds the first radial bearing 51. The second radial bearing 52 is cylindrical. The second radial bearing 52 is held by the second radial bearing holder 26. Therefore, the second radial bearing holder 26 holds the second radial bearing 52.

The first radial bearing 51 supports the first shaft member 44 so that it can rotate in the radial direction. The second radial bearing 52 supports the second shaft member 45 so that it can rotate in the radial direction. The first radial bearing 51 and the second radial bearing 52 support the rotor 33 so that it can rotate in the radial direction at both sides of the tubular member 41 in the axial direction of the tubular member 41. Note that the "radial direction" is the direction perpendicular to the axial direction of the tubular member 41.

As shown in FIG. 2, the centrifugal compressor 10 is equipped with a thrust bearing 53. The thrust bearing 53 is accommodated in the thrust bearing accommodation chamber 19. Therefore, the thrust bearing accommodation chamber 19 accommodates the thrust bearing 53. The thrust bearing 53 rotatably supports the support portion 48 in the thrust direction. Therefore, the thrust bearing 53 rotatably supports the rotating shaft 43 in the thrust direction between the impeller 49 and the first radial bearing 51 via the support portion 48. Note that the "thrust direction" is a direction parallel to the axial direction of the cylindrical member 41. In this manner, the rotor 33 is rotatably supported by the housing 11.

As shown in FIG. 3, the housing 11 has a discharge passage 59. The discharge passage 59 penetrates the second radial bearing retaining portion 26 and the end wall 12a of the motor housing 12. A first end of the discharge passage 59 communicates with the inside of the motor chamber 18. A second end of the discharge passage 59 communicates with the outside of the housing 11.

<Fuel Cell System 55>
As shown in Fig. 1, the centrifugal compressor 10 configured as described above constitutes a part of a fuel cell system 55 mounted on a fuel cell vehicle. In addition to the centrifugal compressor 10, the fuel cell system 55 includes a fuel cell stack 56, a supply flow path 57, and a discharge flow path 58. The fuel cell stack 56 is composed of a plurality of battery cells (not shown). The supply flow path 57 connects the discharge chamber 24 and the fuel cell stack 56. The discharge flow path 58 connects the fuel cell stack 56 and the turbine scroll flow path 29.

When the rotor 33 rotates, the impeller 49 and the turbine wheel 50 rotate integrally with the rotor 33. Therefore, the motor 31 rotates the impeller 49. When the impeller 49 rotates, air is drawn into the impeller chamber 23 from the suction port 22. Therefore, the suction port 22 draws air into the impeller chamber 23. The air flowing through the suction port 22 is cleaned by an air cleaner (not shown).

Air drawn into the impeller chamber 23 from the intake port 22 is compressed as the impeller 49 rotates, passes through the compressor diffuser passage 25, and is discharged from the discharge chamber 24 to the supply passage 57. The air discharged from the discharge chamber 24 to the supply passage 57 is then supplied to the fuel cell stack 56 via the supply passage 57. The air supplied to the fuel cell stack 56 is used to generate electricity in the fuel cell stack 56. The air passing through the fuel cell stack 56 is then discharged to the exhaust passage 58 as exhaust air from the fuel cell stack 56.

The exhaust gas from the fuel cell stack 56 is drawn into the turbine scroll passage 29 via the exhaust passage 58. The exhaust gas from the fuel cell stack 56 drawn into the turbine scroll passage 29 is introduced into the turbine chamber 28 through the communication passage 30. The turbine wheel 50 rotates due to the exhaust gas from the fuel cell stack 56 introduced into the turbine chamber 28. In addition to being rotated by the drive of the motor 31, the rotor 33 also rotates due to the rotation of the turbine wheel 50 which is rotated by the exhaust gas from the fuel cell stack 56. The rotation of the rotor 33 is assisted by the rotation of the turbine wheel 50 due to the exhaust gas from the fuel cell stack 56. The exhaust gas that has passed through the turbine chamber 28 is discharged to the outside from the discharge port 27.

<First Member 61 and Second Member 62>
As shown in Fig. 2, the first shaft member 44 has a first member 61 and a second member 62. Thus, the centrifugal compressor 10 includes the first member 61 and the second member 62. The first member 61 is cylindrical. The first member 61 penetrates the impeller 49. A first end of the first member 61 protrudes from the tip end surface of the impeller 49. The inside of the first member 61 forms an axial passage 63. Thus, the axial passage 63 is formed in the first member 61. Thus, the rotor 60 includes the axial passage 63.

The axis of the axial passage 63 coincides with the axis of the first member 61. A first end of the axial passage 63 opens into a first end face of the first member 61. Thus, the axial passage 63 opens into one end of the first shaft member 44 where the impeller 49 is provided, and communicates with the suction port 22. The axial passage 63 penetrates the interior of the first member 61 in the axial direction of the rotating shaft 43. Thus, the axial passage 63 extends inside the first shaft member 44 in the axial direction of the rotating shaft 43.

As shown in FIG. 5, the first member 61 has a bearing portion 64 and a press-fit portion 65. The bearing portion 64 is located inside the first radial bearing retaining portion 21. The bearing portion 64 is supported by the first radial bearing 51.

The press-fit portion 65 is located closer to the second end of the first member 61 than the bearing portion 64. The press-fit portion 65 is the second end of the first member 61. The press-fit portion 65 is continuous with the bearing portion 64. The outer diameter of the press-fit portion 65 is smaller than the outer diameter of the bearing portion 64. The press-fit portion 65 is disposed inside the tubular member 41. The outer peripheral surface of the bearing portion 64 and the outer peripheral surface of the press-fit portion 65 are connected by an annular step surface 66. The step surface 66 extends in the radial direction of the rotating shaft 43.

The first member 61 has a shroud surface 67. The shroud surface 67 is continuous with the second end of the axial passage 63. Therefore, the shroud surface 67 is continuous with the end of the axial passage 63 opposite the suction port 22. The shroud surface 67 extends in a direction away from the suction port 22 as it moves away from the axial passage 63. The shroud surface 67 is a surface curved in an arc that convexly faces the axis of the first member 61. The shroud surface 67 is the inner surface of a conical hole that opens into the end face of the press-in portion 65. The end of the shroud surface 67 opposite the axial passage 63 is continuous with the outer surface of the press-in portion 65. The end of the shroud surface 67 opposite the axial passage 63 is located inside the tubular member 41.

The second member 62 is cylindrical. The outer diameter of the second member 62 is the same as the outer diameter of the press-fit portion 65 of the first member 61. The second member 62 is disposed closer to the permanent magnet 42 than the first member 61. The second member 62 is disposed inside the tubular member 41.

The second member 62 has a hub surface 68. The hub surface 68 extends along the shroud surface 67. The hub surface 68 is an arc-shaped curved surface that is concave toward the axis of the second member 62. The hub surface 68 gradually approaches the shroud surface 67 as it moves away from the axial path 63.

The second member 62 is provided with a plurality of blades 69. Thus, the plurality of blades 69 are provided on the second member 62. The plurality of blades 69 are integrally formed with the second member 62. Each blade 69 stands upright from the hub surface 68. The plurality of blades 69 extend from the hub surface 68 toward the shroud surface 67. The outer edge of each blade 69 that faces the shroud surface 67 extends along the shroud surface 67. The outer edge of each blade 69 that faces the shroud surface 67 is in contact with the shroud surface 67.

The press-fit portion 65 of the first member 61 is press-fitted into the inner circumferential surface of the first end of the tubular member 41. The step surface 66 abuts against the first end face of the tubular member 41. The step surface 66 and the first end face of the tubular member 41 are joined by, for example, welding or brazing. The second member 62 is press-fitted into the inner circumferential surface of the first end of the tubular member 41. In this way, the tubular member 41 connects the first member 61 and the second member 62 with the outer circumferential edge of the shroud surface 67 and the outer circumferential edge of the hub surface 68 straddling each other in the axial direction of the rotating shaft 43.

The cylindrical member 41 has a plurality of communication holes 70 formed therein. Each communication hole 70 is connected to the space between the shroud surface 67 and the hub surface 68, and also to the space between adjacent blades 69 in the circumferential direction of the second member 62. Each communication hole 70 opens into the motor chamber 18.

The rotating body 60 has a plurality of paths 71. The plurality of paths 71 is formed by the space between the shroud surface 67 and the hub surface 68, and by the space between adjacent blades 69 in the circumferential direction of the second member 62, and by each communication hole 70. Therefore, the shroud surface 67, the hub surface 68, and the plurality of blades 69 define a portion of each path 71. The communication hole 70 forms a portion of each path 71. The plurality of paths 71 extend inside the first shaft member 44 in the radial direction of the rotating shaft 43. The plurality of paths 71 extend inside the rotating body 60 in the radial direction of the rotating shaft 43 and communicate with the inside of the motor chamber 18. Each path 71 communicates with a space inside the first coil end 36a in the motor chamber 18. The plurality of paths 71 introduce air from the shaft path 63 into the motor chamber 18. In this way, the tubular member 41 has a first member 61 and a second member 62 inside, forms a part of each path 71, and opens into the motor chamber 18.

[Operation of the First Embodiment]
Next, the operation of the first embodiment will be described.
A portion of the air from the suction port 22 is introduced into the axial passage 63 and flows through the axial passage 63 and each of the paths 71. The air flowing through each of the paths 71 is introduced into the motor chamber 18. The air introduced into the motor chamber 18 passes between the stator 32 and the rotor 33, and is discharged to the outside of the housing 11 through the discharge passage 59. The motor 31 is cooled by the air introduced into the motor chamber 18. In this way, in the centrifugal compressor 10, the motor 31 is cooled by the air introduced into the motor chamber 18 from the suction port 22 through the axial passage 63 and each of the paths 71.

A portion of each path 71 is formed by a shroud surface 67, a hub surface 68, and a number of vanes 69. The air flowing through each path 71 configured in this way is easily accelerated by the centrifugal force that accompanies the rotation of the rotor 60. Therefore, air is efficiently introduced from each path 71 into the motor chamber 18. As a result, the motor 31 is efficiently cooled.

[Effects of the First Embodiment]
The first embodiment can provide the following effects.
(1-1) The cylindrical member 41 has a first member 61 and a second member 62 therein, forms a part of each path 71, and opens into the motor chamber 18. With this, the cylindrical member 41 has the first member 61 and the second member 62 therein, and thus it is possible to employ a rotor 60 in which a part of each path 71 is formed from a shroud surface 67, a hub surface 68, and a plurality of blades 69. Therefore, for example, in order to form a plurality of paths 71 having such a configuration inside the rotating shaft 43, it is not necessary to manufacture the rotating shaft 43 using a mold with a complex structure. Therefore, it is possible to efficiently cool the motor 31 while keeping costs down.

(1-2) The first shaft member 44 has a first member 61 and a second member 62. A plurality of radial passages 71 extend inside the first shaft member 44 in the radial direction of the rotating shaft 43. An axial passage 63 is formed in the first member 61. A plurality of blades 69 are integrally formed with the second member 62 and extend from the hub surface 68 toward the shroud surface 67. This configuration is suitable for introducing air into the motor chamber 18 from the side where the first shaft member 44 is located.

[Second embodiment]
A second embodiment of a centrifugal compressor will be described below with reference to Figures 6 and 7. In the embodiment described below, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted or simplified. The second embodiment differs from the first embodiment in that the path is provided in the second shaft member, not in the first shaft member. In the second embodiment, the first shaft member does not have a first member and a second member.

As shown in FIG. 6, the housing 11 has a discharge passage 75. The discharge passage 75 passes through the first plate 15. A first end of the discharge passage 75 communicates with the inside of the motor chamber 18. A second end of the discharge passage 75 communicates with the outside of the housing 11.

The axial passage 63 passes through the interior of the first shaft member 44 in the axial direction of the rotating shaft 43. The permanent magnet 42 has a connecting passage 76. The connecting passage 76 passes through the permanent magnet 42 in the axial direction. The first end of the connecting passage 76 is connected to the axial passage 63.

As shown in FIG. 7, the second shaft member 45 has a first member 81 and a second member 82. Thus, the centrifugal compressor 10 includes the first member 81 and the second member 82. The first member 81 is cylindrical. The first member 81 is disposed closer to the permanent magnet 42 than the second member 82. The first member 81 is disposed inside the tubular member 41.

The first member 81 has a shroud surface 83. The shroud surface 83 is continuous with the second end of the connecting passage 76. The shroud surface 83 extends in a direction away from the permanent magnet 42 as it moves away from the connecting passage 76. The shroud surface 83 is an arc-shaped curved surface that is convex toward the axis of the first member 81. The shroud surface 83 is the inner surface of a conical hole that penetrates the first member 81 in the axial direction. The end of the shroud surface 83 opposite the connecting passage 76 is continuous with the outer surface of the first member 81. The end of the shroud surface 83 opposite the connecting passage 76 is located inside the tubular member 41.

The second member 82 is cylindrical. The second member 82 has a bearing portion 84 and a press-fit portion 85. The bearing portion 84 is located inside the second radial bearing retaining portion 26. The bearing portion 84 is supported by the second radial bearing 52.

The press-fit portion 85 is located closer to the first member 81 than the bearing portion 84. The press-fit portion 85 is continuous with the bearing portion 84. The outer diameter of the press-fit portion 85 is smaller than the outer diameter of the bearing portion 84. The press-fit portion 85 is disposed inside the tubular member 41. The outer peripheral surface of the bearing portion 84 and the outer peripheral surface of the press-fit portion 85 are connected by an annular stepped surface 86. The stepped surface 86 extends in the radial direction of the rotating shaft 43. The outer diameter of the press-fit portion 85 is the same as the outer diameter of the first member 81.

The second member 82 has a hub surface 87. The hub surface 87 extends along the shroud surface 83. The hub surface 87 is an arc-shaped curved surface that is concave toward the axis of the second member 82. The hub surface 87 gradually approaches the shroud surface 67 as it moves away from the connecting passage 76. The hub surface 87 is continuous with the outer peripheral surface of the press-fit portion 85.

The second member 82 is provided with a plurality of wings 88. Thus, the plurality of wings 88 are provided on the second member 82. The plurality of wings 88 are integrally formed with the second member 82. Each of the wings 88 stands upright from the hub surface 87. The plurality of wings 88 extend from the hub surface 87 toward the shroud surface 83. The outer edge of each of the wings 88 on the shroud surface 83 side extends along the shroud surface 83. The outer edge of each of the wings 88 on the shroud surface 83 side is in contact with the shroud surface 83.

The first member 81 is press-fitted into the inner peripheral surface of the second end of the tubular member 41. The press-fit portion 85 of the second member 82 is press-fitted into the inner peripheral surface of the second end of the tubular member 41. The step surface 86 is in contact with the second end face of the tubular member 41. The step surface 86 and the second end face of the tubular member 41 are joined by, for example, welding or brazing. In this way, the tubular member 41 connects the first member 81 and the second member 82 with the outer peripheral edge of the shroud surface 83 and the outer peripheral edge of the hub surface 87 straddling each other in the axial direction of the rotating shaft 43.

The cylindrical member 41 has a plurality of communication holes 89 formed therein. Each communication hole 89 is connected to the space between the shroud surface 83 and the hub surface 87, and also to the space between adjacent blades 88 in the circumferential direction of the second member 82. Each communication hole 89 opens into the motor chamber 18.

The rotating body 60 has a plurality of paths 90. The plurality of paths 90 is formed by the space between the shroud surface 83 and the hub surface 87, the space between adjacent blades 88 in the circumferential direction of the second member 82, and each communication hole 89. Therefore, the shroud surface 83, the hub surface 87, and the plurality of blades 88 define a portion of each path 90. And the communication hole 89 forms a portion of each path 90. The plurality of paths 90 extend in the radial direction of the rotating shaft 43 inside the second shaft member 45. The plurality of paths 90 extend in the radial direction of the rotating shaft 43 inside the rotating body 60 and communicate with the inside of the motor chamber 18. Each path 90 communicates with a space inside the second coil end 36b in the motor chamber 18. Each path 90 communicates with the connecting passage 76. Therefore, the connecting passage 76 connects the shaft path 63 and the plurality of paths 90. Then, air from the axial passage 63 is introduced into the motor chamber 18 via the connecting passage 76 and each path 90. Therefore, the multiple paths 90 introduce air from the axial passage 63 into the motor chamber 18. In this way, the tubular member 41 has a first member 81 and a second member 82 inside, forms a part of each path 90, and opens into the motor chamber 18.

[Operation of the second embodiment]
Next, the operation of the second embodiment will be described.
A portion of the air from the suction port 22 is introduced into the axial passage 63 and flows through the axial passage 63, the connecting passage 76, and each of the paths 90. The air flowing through each of the paths 90 is introduced into the motor chamber 18. The air introduced into the motor chamber 18 passes between the stator 32 and the rotor 33, and is discharged to the outside of the housing 11 through the discharge passage 75. The motor 31 is cooled by the air introduced into the motor chamber 18. In this way, in the centrifugal compressor 10, the motor 31 is cooled by the air introduced into the motor chamber 18 from the suction port 22 through the axial passage 63 and each of the paths 90.

A portion of each path 90 is formed by a shroud surface 83, a hub surface 87, and a number of vanes 88. The air flowing through each path 90 configured in this way is easily accelerated by the centrifugal force that accompanies the rotation of the rotor 60. Therefore, air is efficiently introduced from each path 90 into the motor chamber 18. As a result, the motor 31 is efficiently cooled.

[Effects of the second embodiment]
In the second embodiment, in addition to the effect (1-1) of the first embodiment, the following effect can be obtained.

(2-1) The second shaft member 45 has a first member 81 and a second member 82. A plurality of paths 90 extend inside the second shaft member 45 in the radial direction of the rotating shaft 43. The permanent magnet 42 has a connecting passage 76 that connects the axial path 63 and the plurality of paths 90. A plurality of blades 88 are formed integrally with the second member 62 and extend from the hub surface 87 toward the shroud surface 83. This configuration is suitable for introducing air into the motor chamber 18 from the side where the second shaft member 45 is located.

(2-2) Air passes through the connecting passage 76. Therefore, the permanent magnet 42 can be cooled by the air flowing through the connecting passage 76. This allows the motor 31 to be cooled more efficiently.

[Example of change]
The above-described embodiments may be modified as follows: The above-described embodiments and the following modifications may be combined with each other to the extent that no technical contradiction occurs.

In the first embodiment, the multiple blades 69 may be provided on the first member 61. In this case, the multiple blades 69 extend from the shroud surface 67 toward the hub surface 68. In short, it is sufficient that the multiple blades 69 extend from one of the shroud surface 67 and the hub surface 68 toward the other. And, it is sufficient that the multiple blades 69 are provided on one of the first member 61 and the second member 62.

○ In the first embodiment, the first shaft member 44 does not have to have the second member 62. In this case, for example, a hub surface is formed on the permanent magnet 42. Therefore, the permanent magnet 42 also serves as the second member having the hub surface. The centrifugal compressor 10 is provided with a plurality of blades extending from the shroud surface 67 toward the hub surface of the permanent magnet 42. Therefore, the plurality of blades are provided on the first member.

In the second embodiment, the multiple blades 88 may be provided on the first member 81. In this case, the multiple blades 88 extend from the shroud surface 83 toward the hub surface 87. In short, it is sufficient that the multiple blades 88 extend from one of the shroud surface 83 and the hub surface 87 toward the other. And, it is sufficient that the multiple blades 88 are provided on one of the first member 81 and the second member 82.

In the second embodiment, the second shaft member 45 does not have to have the first member 61. In this case, for example, a shroud surface is formed on the permanent magnet 42. Therefore, the permanent magnet 42 also serves as the first member having a shroud surface.

In the first embodiment, the step surface 66 and the first end face of the tubular member 41 do not have to be joined by, for example, welding or brazing. In short, the first member 61 may be fixed to the tubular member 41 only by pressing the press-fit portion 65 against the inner circumferential surface of the first end of the tubular member 41.

In the second embodiment, the step surface 86 and the second end surface of the tubular member 41 do not have to be joined by, for example, welding or brazing. In short, the second member 82 may be fixed to the tubular member 41 only by pressing the press-fit portion 85 against the inner circumferential surface of the second end of the tubular member 41.

In each of the above embodiments, the permanent magnet 42 may not be pressed into the inner circumferential surface of the tubular member 41, but may be adhered to the inner circumferential surface of the tubular member 41, for example, with an adhesive. In short, it is sufficient that the permanent magnet 42 is fixed to the inside of the tubular member 41.

In each of the above-described embodiments, the centrifugal compressor 10 does not necessarily have to include the turbine wheel 50 .
In each of the above-described embodiments, the centrifugal compressor 10 may be configured to include an impeller instead of the turbine wheel 50. That is, the centrifugal compressor 10 may be configured such that an impeller is attached to each of the first shaft member 44 and the second shaft member 45, and air compressed by one impeller is compressed again by the other impeller.

In each of the above-described embodiments, the magnetic body is not limited to the permanent magnet 42 and may be, for example, a laminated core, an amorphous core, or a powder core.
In each of the above-described embodiments, the cylindrical member 41 may be made of, for example, carbon fiber reinforced plastic. In short, the material of the cylindrical member 41 is not particularly limited.

○ In each of the above embodiments, the centrifugal compressor 10 does not have to be mounted on a fuel cell vehicle. In other words, the centrifugal compressor 10 is not limited to being mounted on a vehicle.

Claims

A rotor including a rotating shaft and an impeller configured to rotate integrally with the rotating shaft to compress air;
a motor configured to rotate the rotary shaft;
a housing having an impeller chamber that houses the impeller, a motor chamber that houses the motor, and an intake port that draws air into the impeller chamber,
The motor is
a stator fixed to the housing;
a rotor configured to rotate integrally with the rotating shaft, disposed inside the stator, and constituting a part of the rotating body;
The rotor is
A cylindrical member;
a magnetic body fixed to the inside of the cylindrical member;
the rotating shaft includes a first shaft member and a second shaft member provided on both sides of the magnetic body in an axial direction of the cylindrical member,
The impeller is connected to the first shaft member,
The rotating body is
an axial passage that opens at one end of the first shaft member to which the impeller is connected and communicates with the suction port, and that extends through the first shaft member in the axial direction of the rotary shaft;
a plurality of passages extending in a radial direction of the rotary shaft through the interior of the rotor and communicating with the motor chamber, for introducing air from the axial passage into the motor chamber;
A centrifugal compressor in which the motor is cooled by air introduced into the motor chamber from the suction port through the axial passage and each of the radial passages,
a first member having a shroud surface that defines a portion of each of the paths;
a second member having a hub surface extending along the shroud surface and defining a portion of each of the paths;
a plurality of vanes extending from one of the shroud surface and the hub surface toward the other and defining a portion of each of the paths;
the plurality of wings are provided on one of the first member and the second member,
The cylindrical member has the first member and the second member therein, forms a part of each of the paths, and is open into the motor chamber.
The first shaft member has the first member and the second member,
The plurality of paths extend in the radial direction inside the first shaft member,
The first member has the shaft passage formed therein,
2. The centrifugal compressor according to claim 1, wherein the plurality of vanes are integrally formed with the second member and extend from the hub surface toward the shroud surface.
the second shaft member has the first member and the second member,
The plurality of paths extend in the radial direction inside the second shaft member,
the magnetic body has a connection passage that connects the axial path and the plurality of paths,
2. The centrifugal compressor according to claim 1, wherein the plurality of vanes are integrally formed with the second member and extend from the hub surface toward the shroud surface.