Centrifugal compressor

Abstract

The present application relates to a centrifugal compressor in which a magnetic body is efficiently cooled. The circumferential distance of the 2nd shaft member (45) of each passage (70) gradually increases toward the radially outer side of the 2nd shaft member. Thus, air flowing in each passage easily flows toward the radially outer side of the 2nd shaft member by centrifugal force accompanying rotation of the 2nd shaft member. In addition, the length (H1) of the 2nd shaft member in the circumferential direction of the intervening face (76) is shorter than the length (H2) of the 2nd shaft member in the circumferential direction of the opening portion (71) of each passage. Therefore, air remaining in the motor chamber in the vicinity of the intervening face (76) is relatively small. Thus, the flow of air introduced from each passage into the motor chamber is less likely to be hindered by air remaining in the motor chamber in the vicinity of the intervening face. Furthermore, a portion of the air from the suction port easily flows into the motor chamber via the shaft passage (60) and each passage, and thus air easily flows in the shaft passage (60).

Description

TECHNICAL FIELD

[0001] The present application relates to a centrifugal compressor. BACKGROUND

[0002] A centrifugal compressor has a compressor impeller, a motor, and a casing. The compressor impeller compresses air. The motor rotates the compressor impeller. The casing has an impeller chamber, a motor chamber, and a suction port. The impeller chamber houses the compressor impeller. The motor chamber houses the motor. The suction port sucks air into the impeller chamber.

[0003] The motor has a stator and a rotor. The stator is fixed to the casing. The rotor is disposed inside the stator. The rotor has a case member, a magnetic body, and a first shaft member and a second shaft member. The magnetic body is fixed to the inside of the case member. The first shaft member and the second shaft member are disposed on both sides of the magnetic body in the axial direction of the case member. The compressor impeller is connected to the first shaft member, for example.

[0004] In such a centrifugal compressor, eddy currents are generated in the magnetic body, and heat is generated in the magnetic body. Therefore, it is considered that a portion of the air compressed by the compressor impeller is introduced into the motor chamber, as in Patent Literature 1, for example. By thus introducing the compressed air into the motor chamber, the magnetic body can be cooled by the compressed air.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2011-202588 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, the air compressed by the compressor impeller is higher in temperature than the air before compression, and therefore the cooling of the magnetic body can not be sufficient. Therefore, in such a centrifugal compressor, it is desirable to efficiently cool the magnetic body.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] A centrifugal compressor that solves the above problems is provided with: a compressor impeller that compresses air; a motor that rotates the compressor impeller; and a casing that has an impeller chamber that houses the compressor impeller, a motor chamber that houses the motor, and a suction port that sucks in air to the impeller chamber, the motor being provided with: a stator that is fixed to the casing; and a rotor that is disposed inside the stator, the rotor being provided with: a cylinder member; a magnetic body that is fixed to the inside of the cylinder member; and a first shaft member and a second shaft member that are provided on both sides across the magnetic body in the axial direction of the cylinder member, the compressor impeller being linked to the first shaft member, the centrifugal compressor being characterized in that the rotor is provided with: a shaft passage that opens at one end on the compressor impeller side of the first shaft member so as to communicate with the suction port and extends along the axial direction of the rotor inside the rotor; and a plurality of radial passages that communicate with the shaft passage and extend from the shaft passage toward the outer peripheral surface of the second shaft member so as to communicate with the motor chamber, the casing having a discharge port that discharges air introduced from the suction port into the motor chamber to the outside of the casing, the distance / dimension of the second shaft member in the circumferential direction of each radial passage gradually lengthening as it goes toward the radially outer side of the second shaft member, each radial passage having an opening portion that opens at the outer peripheral surface of the second shaft member, the outer peripheral surface of the second shaft member having an intervening surface that intervenes between the opening portions of adjacent radial passages in the circumferential direction of the second shaft member, the length of the second shaft member in the circumferential direction of the intervening surface being shorter than the length of the second shaft member in the circumferential direction of the opening portion.

[0012] Thus, a portion of the air from the suction port is introduced to the shaft passage and flows in the shaft passage and each radial passage. The air flowing in each radial passage is introduced into the motor chamber. The air introduced into the motor chamber is discharged to the outside of the casing from the discharge port. The magnetic body is cooled by the air flowing in the shaft passage. Thus, the magnetic body can be cooled using air that is lower in temperature than the compressed air.

[0013] Here, the distance of the second shaft member in the circumferential direction of each radial passage gradually lengthens as it goes toward the radially outer side of the second shaft member. Therefore, the air flowing in each radial passage easily flows in each radial passage toward the radially outer side of the second shaft member by centrifugal force accompanying rotation of the second shaft member. In addition, the length of the second shaft member in the circumferential direction of the intervening surface is shorter than the length of the second shaft member in the circumferential direction of the opening portion of each radial passage. Thus, it is possible to make the air that remains in the motor chamber in the vicinity of the intervening surface relatively small. Therefore, it is possible to inhibit the flow of the air introduced from each radial passage into the motor chamber from being impeded by the air that remains in the motor chamber in the vicinity of the intervening surface. As a result, a portion of the air from the suction port easily flows into the motor chamber via the shaft passage and each radial passage, and thus the air easily flows in the shaft passage. Therefore, it is possible to efficiently cool the magnetic body.

[0014] In the centrifugal compressor described above, it is preferable that the respective passages extend in a direction away from the magnetic body as they depart from the shaft passage.

[0015] Thus, the air flowing in the respective passages is easily compressed by the centrifugal force accompanying rotation of the second shaft member. Therefore, a portion of the air from the suction port is easily drawn toward the shaft passage. Thus, the air is more easily made to flow in the shaft passage. Therefore, the magnetic body can be more efficiently cooled.

[0016] In the centrifugal compressor described above, it is preferable that the distance in the axial direction of the second shaft member of the respective passages gradually shorten as they depart toward the radially outer side of the second shaft member.

[0017] Thus, the air flowing in the respective passages is more easily compressed by the centrifugal force accompanying rotation of the second shaft member. Therefore, a portion of the air from the suction port is more easily drawn toward the shaft passage. Thus, the air is more easily made to flow in the shaft passage. Therefore, the magnetic body can be more efficiently cooled.

[0018] In the centrifugal compressor described above, it is preferable that the centrifugal compressor be provided with a diffusion flow path provided between the stator and the rotor and that pressurizes the air introduced from the respective passages into the motor chamber and makes it flow toward the discharge port.

[0019] Thus, the air introduced from the respective passages into the motor chamber is pressurized by the diffusion flow path while flowing toward the discharge port, and is discharged from the discharge port. Therefore, the air introduced from the respective passages into the motor chamber is easily discharged via the discharge port. As a result, a portion of the air from the suction port is easily drawn toward the shaft passage. Thus, the air is more easily made to flow in the shaft passage. Therefore, the magnetic body can be more efficiently cooled.

[0020] A centrifugal compressor that solves the above problems is provided with: a compressor impeller that compresses air; a motor that rotates the compressor impeller; and a casing that has an impeller chamber that houses the compressor impeller, a motor chamber that houses the motor, and a suction port that sucks in air to the impeller chamber, the motor being provided with: a stator that is fixed to the casing; and a rotor that is disposed inside the stator, the rotor being provided with: a cylinder member; a magnetic body that is fixed to the inside of the cylinder member; and a first shaft member and a second shaft member that are provided on both sides across the magnetic body in the axial direction of the cylinder member, the compressor impeller being linked to the first shaft member, the centrifugal compressor being characterized in that the rotor is provided with: a shaft passage that opens at one end on the compressor impeller side of the first shaft member so as to communicate with the suction port and extends along the axial direction of the rotor inside the rotor; and a plurality of radial passages that communicate with the shaft passage and extend from the shaft passage toward the outer peripheral surface of the first shaft member so as to communicate with the motor chamber, the casing having a discharge port that discharges air introduced from the suction port into the motor chamber to the outside of the casing, the distance in the peripheral direction of the first shaft member of each radial passage gradually lengthening as it goes toward the radially outer side of the first shaft member, each radial passage having an opening portion that opens at the outer peripheral surface of the first shaft member, the outer peripheral surface of the first shaft member having an intervening surface that intervenes between the opening portions of adjacent radial passages in the peripheral direction of the first shaft member, the length in the peripheral direction of the first shaft member of the intervening surface being shorter than the length in the peripheral direction of the first shaft member of the opening portions.

[0021] Thus, a portion of the air from the suction port is introduced into the shaft passage and flows in the shaft passage and each radial passage. The air flowing in each radial passage is introduced into the motor chamber. The air introduced into the motor chamber is discharged to the outside of the casing from the discharge port. The magnetic body is cooled by the air introduced into the motor chamber. The air introduced into the motor chamber is lower in temperature than the air after compression. Therefore, the magnetic body can be efficiently cooled.

[0022] Here, the distance in the peripheral direction of the first shaft member of each radial passage gradually lengthens as it goes toward the radially outer side of the first shaft member. Therefore, the air flowing in each radial passage easily flows in each radial passage toward the radially outer side of the first shaft member by centrifugal force accompanying rotation of the first shaft member. In addition, the length in the peripheral direction of the first shaft member of the intervening surface is shorter than the length in the peripheral direction of the first shaft member of the opening portions of each radial passage. Thus, the air in the motor chamber that remains in the vicinity of the intervening surface can be made relatively small. Therefore, the flow of the air introduced from each radial passage into the motor chamber can be inhibited by the air in the motor chamber that remains in the vicinity of the intervening surface. As a result, a portion of the air from the suction port easily flows into the motor chamber via the shaft passage and each radial passage. Therefore, the magnetic body can be efficiently cooled.

[0023] In the centrifugal compressor described above, it is preferable that the respective passages extend in a direction away from the suction port toward the shaft passage.

[0024] Thus, the air flowing in the respective passages is easily compressed by the centrifugal force accompanying rotation of the first shaft member. Therefore, a portion of the air from the suction port is easily drawn toward the shaft passage. Thus, the air is easily introduced into the motor chamber. Therefore, the magnetic body can be more efficiently cooled.

[0025] In the centrifugal compressor described above, it is preferable that the distance in the axial direction of the first shaft member of the respective passages gradually become shorter toward the radially outer side of the first shaft member.

[0026] Thus, the air flowing in the respective passages is more easily compressed by the centrifugal force accompanying rotation of the first shaft member. Therefore, a portion of the air from the suction port is more easily drawn toward the shaft passage. Thus, the air is more easily introduced into the motor chamber. Therefore, the magnetic body can be more efficiently cooled.

[0027] In the centrifugal compressor described above, it is preferable that the centrifugal compressor include a partition wall that guides the air introduced from the respective passages into the motor chamber toward between the stator and the rotor.

[0028] Thus, the air introduced from the respective passages into the motor chamber is guided by the partition wall toward between the stator and the rotor. Thus, the air introduced from the respective passages into the motor chamber easily flows between the stator and the rotor, and therefore the magnetic body can be more efficiently cooled using the air flowing between the stator and the rotor.

[0029] Effects of the Invention

[0030] According to the present application, the magnetic body can be efficiently cooled. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a sectional view of a centrifugal compressor of the first embodiment.

[0032] Figure 2 is a sectional view of a centrifugal compressor of the first embodiment.

[0033] Figure 3 is a sectional view of a centrifugal compressor of the first embodiment.

[0034] Figure 4 is a sectional view of a centrifugal compressor of the first embodiment.

[0035] Figure 5 is a sectional view of a centrifugal compressor of the first embodiment.

[0036] Figure 6 yes Figure 5 The 6-6 line section view.

[0037] Figure 7 yes Figure 5 Sectional view along line 7-7.

[0038] Figure 8 This is a cross-sectional view of the centrifugal compressor according to the second embodiment.

[0039] Figure 9 This is a cross-sectional view showing an enlarged portion of a centrifugal compressor.

[0040] Figure 10 This is a cross-sectional view showing an enlarged portion of a centrifugal compressor.

[0041] Figure 11 yes Figure 10 Sectional view along line 11-11.

[0042] Figure 12 yes Figure 10 Sectional view along line 12-12.

[0043] Figure 13 This is a cross-sectional view showing an enlarged portion of a centrifugal compressor according to another embodiment.

[0044] Explanation of reference numerals in the attached figures

[0045] 10…Centrifugal compressor, 11…Casing, 18…Motor chamber, 22…Suction port, 23…Impeller chamber, 31…Motor, 32…Stator, 33…Rotor, 41…Cylinder component, 42…Permanent magnet as a magnetic body, 44…First shaft component, 45…Second shaft component, 49…Compressor impeller, 60, 87…Shaft path, 70, 98…Path, 71, 99…Opening, 76, 100…Interface, 78…Diffusion path, 80…Discharge port, 101…Blocking wall. Detailed Implementation

[0046] [First Implementation]

[0047] The following is based on Figures 1-7 A first embodiment embodying the centrifugal compressor will be described. The centrifugal compressor of this embodiment is mounted in a fuel cell vehicle. The centrifugal compressor compresses air.

[0048] Centrifugal Compressor 10

[0049] like Figure 1As shown, 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 sealing plate 17.

[0050] 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. A first plate 15 is connected to the end of the peripheral wall 12b of the motor housing 12 on the open side. The first plate 15 closes the opening of the peripheral wall 12b of the motor housing 12. Furthermore, the motor chamber 18 is defined by the end wall 12a, the peripheral wall 12b, and the first plate 15 of the motor housing 12. Therefore, the housing 11 has a motor chamber 18.

[0051] like Figure 2 As shown, 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 to 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 surface 15f of the first recess 15c. The axis of the first recess 15c is aligned with the axis of the second recess 15d.

[0052] The sealing plate 17 is embedded in the first recess 15c. The sealing plate 17 is mounted to the first plate 15, for example, by bolts (not shown). The sealing plate 17 closes the opening of the second recess 15d. Furthermore, the sealing plate 17 and the second recess 15d define the thrust bearing receiving chamber 19. Therefore, the housing 11 has the thrust bearing receiving chamber 19. Additionally, the sealing plate 17 has a shaft insertion through-hole 17h. The shaft insertion through-hole 17h is formed in the central portion of the sealing plate 17. The shaft insertion through-hole 17h opens into the thrust bearing receiving chamber 19.

[0053] 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 from the center of the end face 15b on the motor housing 12 side of the first plate 15 into the motor chamber 18. The first radial bearing retaining portion 21 communicates with the motor chamber 18. The first radial bearing retaining portion 21 passes through the first plate 15 and opens at the bottom surface 15h of the second recess 15d. Therefore, the first radial bearing retaining portion 21 communicates with the thrust bearing receiving chamber 19. The axis of the first radial bearing retaining portion 21 is aligned with the axis of the first recess 15c and the axis of the second recess 15d.

[0054] The compressor housing 13 is cylindrical. The compressor housing 13 has a circular suction port 22. Therefore, the housing 11 has a 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 aligned with the axis of the shaft insertion hole 17h of the sealing plate 17. The suction port 22 opens on the end face of the compressor housing 13 opposite to the first plate 15.

[0055] An impeller chamber 23, a discharge chamber 24, and a compressor diffusion path 25 are formed between the compressor housing 13 and the sealing plate 17. Therefore, the housing 11 has an impeller chamber 23. The sealing plate 17 separates the impeller chamber 23 from the thrust bearing housing 19. The impeller chamber 23 communicates with the suction port 22. The impeller chamber 23 has a generally frustum-shaped bore that gradually widens from the suction port 22 toward the sealing plate 17. The discharge chamber 24 extends around the axis of the suction port 22 around the impeller chamber 23. The compressor diffusion path 25 connects the impeller chamber 23 and the discharge chamber 24. The impeller chamber 23 communicates with the shaft insertion through-hole 17h of the sealing plate 17.

[0056] like Figure 3 As shown, 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 into the motor chamber 18 from the center of the inner surface of the end wall 12a of the motor housing 12. The second radial bearing retaining portion 26 communicates with 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 has an opening on the outer surface of the end wall 12a. The axis of the first radial bearing retaining portion 21 is aligned with the axis of the second radial bearing retaining portion 26.

[0057] 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 through hole 16h. The shaft insertion through hole 16h is formed in the center of the second plate 16.

[0058] 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 to the motor housing 12, with the axis of the discharge port 27 aligned with the axis of the shaft insertion hole 16h of the second plate 16. The discharge port 27 opens on the end face of the turbine housing 14 opposite to the second plate 16.

[0059] A turbine chamber 28, a turbine vortex flow path 29, and a connecting passage 30 are formed between the turbine housing 14 and the end face 16a of the second plate 16. The turbine chamber 28 is connected to the outlet 27. The turbine vortex flow path 29 extends around the axis of the outlet 27 around the turbine chamber 28. The connecting passage 30 connects the turbine chamber 28 and the turbine vortex flow path 29. The turbine chamber 28 is connected to the shaft insertion through hole 16h of the second plate 16.

[0060] <Motor 31>

[0061] As Figure 1 shown, the centrifugal compressor 10 is provided with a motor 31. The motor 31 is housed in the motor chamber 18. Thus, the motor chamber 18 houses the motor 31. Also, the motor 31 is housed in the casing 11.

[0062] The motor 31 is provided with a stator 32 and a rotor 33. The stator 32 has a 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 peripheral surface of the peripheral wall 12b of the motor housing 12. Thus, the stator 32 is fixed to the casing 11. Coil ends 36, which are a part of the coil 35, respectively protrude at both end surfaces of the stator core 34. In the following description, the coil end 36 at a position of the stator core 34 on the side of the first plate 15 is described as a "first coil end 36a". Also, the coil end 36 at a position of the stator core 34 on the side of the end wall 12a of the motor housing 12 is described as a "second coil end 36b".

[0063] As Figure 4 shown, the stator 32 is provided with a resin portion 37. The resin portion 37 covers the stator core 34 and the coil ends 36. The resin portion 37 has a first resin portion 38, a second resin portion 39, and a third resin portion 40. Thus, the stator 32 is provided with the first resin portion 38, the second resin portion 39, and the third resin portion 40. The first resin portion 38 is a cylindrical shape in which the first coil end 36a is covered with resin. The second resin portion 39 is a cylindrical shape in which the second coil end 36b is covered with resin. The third resin portion 40 is a cylindrical shape in which the inner peripheral surface of the stator core 34 is covered with resin. The third resin portion 40 extends inside the stator core 34 in the axial direction of the stator core 34. The third resin portion 40 connects the first resin portion 38 and the second resin portion 39. The inner peripheral surface of the third resin portion 40 is a conical hole in which the inner diameter gradually increases as it goes from the second resin portion 39 toward the first resin portion 38.

[0064] <rotor 33>

[0065] The rotor 33 is disposed inside the stator 32. The rotor 33 is provided with a cylindrical member 41, a permanent magnet 42 that is a magnetic body, and a first shaft member 44 and a second shaft member 45. The cylindrical member 41 is made of, for example, titanium alloy. The cylindrical member 41 is a cylindrical shape in which the axis of the cylindrical member 41 extends linearly. The axial direction of the cylindrical member 41 is also the axial direction of the rotor 33. The outer diameter of the cylindrical member 41 is constant. Thus, the outer peripheral surface of the cylindrical member 41 extends in the axial direction of the rotor 33.

[0066] The permanent magnet 42 is cylindrical. It is disposed inside the cylindrical member 41. The axis of the permanent magnet 42 is aligned with the axis of the cylindrical member 41. The permanent magnet 42 is pressed into the inner circumferential surface of the cylindrical member 41. Therefore, the permanent magnet 42 is fixed to the inner side of the cylindrical member 41. The permanent magnet 42 is magnetized radially. Specifically, the permanent magnet 42 is a cylindrical shape having N and S poles on both sides of its radial direction due to being magnetized radially.

[0067] The length of the axis extending from the permanent magnet 42 is shorter than the length of the axis extending from the cylindrical member 41. The two end faces of the permanent magnet 42 are located inside the cylindrical member 41. Therefore, the two ends located axially in the cylindrical member 41 protrude axially relative to the two end faces of the permanent magnet 42. Furthermore, the two end faces of the cylindrical member 41 protrude axially relative to the two end faces of the stator core 34.

[0068] like Figure 1 As shown, the first shaft member 44 and the second shaft member 45 are disposed on both sides of the cylindrical member 41 in the axial direction, separated by the permanent magnet 42. The first shaft member 44 and the second shaft member 45 are, for example, made of iron.

[0069] The first shaft member 44 is cylindrical. The first end of the first shaft member 44 is inserted into the inner side of the first end of the cylindrical member 41. The first end of the first shaft member 44 is pressed into the inner circumferential surface of the first end of the cylindrical member 41. Therefore, the first shaft member 44 is fixed to the cylindrical member 41. The second end of the first shaft member 44 protrudes from the motor chamber 18 through the inner side of the first radial bearing retaining part 21, the thrust bearing receiving chamber 19, and the shaft insertion through hole 17h into the impeller chamber 23.

[0070] The second shaft member 45 is cylindrical. The first end of the second shaft member 45 is inserted into the inner side of the second end of the cylindrical member 41. The first end of the second shaft member 45 is pressed into the inner circumferential surface of the second end of the cylindrical member 41. Therefore, the second shaft member 45 is fixed to the cylindrical member 41. The second end of the second shaft member 45 protrudes from the motor chamber 18 through the inner side of the second radial bearing retaining part 26 and the shaft insertion through hole 16h into the turbine chamber 28.

[0071] Centrifugal compressor 10 includes a first sealing member 46. The first sealing member 46 is disposed between the shaft insertion hole 17h of sealing plate 17 and the first shaft member 44. The first sealing member 46 suppresses air leakage from impeller chamber 23 toward motor chamber 18. Centrifugal compressor 10 includes a second sealing member 47. The second sealing member 47 is disposed between the shaft insertion hole 16h of second plate 16 and the second shaft member 45. The second sealing member 47 suppresses air leakage from turbine chamber 28 toward motor chamber 18. The first sealing member 46 and the second sealing member 47 are, for example, sealing rings.

[0072] The centrifugal compressor 10 is provided with a support portion 48. The support portion 48 is annularly protruded from the outer peripheral surface of the first shaft member 44. The support portion 48 is a circular plate. The support portion 48 is fixed to the outer peripheral surface of the first shaft member 44 in a state of being annularly protruded from the outer peripheral surface of the first shaft member 44 to the radial direction outer side. 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.

[0073] <Compressor impeller 49>

[0074] The centrifugal compressor 10 is provided with a compressor impeller 49. The compressor impeller 49 is installed to the second end portion of the first shaft member 44. Therefore, the compressor impeller 49 is linked to the first shaft member 44. The compressor impeller 49 is disposed in the first shaft member 44 closer to the second end portion of the first shaft member 44 than the support portion 48. The compressor impeller 49 is a cylindrical shape which is gradually reduced in diameter as from the back surface toward the top surface. The compressor impeller 49 is housed in the impeller chamber 23. Therefore, the impeller chamber 23 houses the compressor impeller 49. The outer edge of the compressor impeller 49 extends along the inner peripheral surface of the impeller chamber 23. The compressor impeller 49 compresses air by rotating integrally with the first shaft member 44.

[0075] <Turbine impeller 50>

[0076] The centrifugal compressor 10 is provided with a turbine impeller 50. The turbine impeller 50 is installed to the second end portion of the second shaft member 45. The turbine impeller 50 is housed in the turbine chamber 28. The turbine impeller 50 rotates integrally with the second shaft member 45.

[0077] <First and second radial bearings 51 and 52>

[0078] The centrifugal compressor 10 is provided with a first radial bearing 51 and a second radial bearing 52. The first radial bearing 51 is a cylindrical shape. The first radial bearing 51 is held to the first radial bearing holding portion 21. The second radial bearing 52 is a cylindrical shape. The second radial bearing 52 is held to the second radial bearing holding portion 26.

[0079] The first radial bearing 51 supports the first shaft member 44 so as to be rotatable in the radial direction. The second radial bearing 52 supports the second shaft member 45 so as to be rotatable in the radial direction. The first radial bearing 51 and the second radial bearing 52 support the rotor 33 so as to be rotatable in the radial direction at positions on the opposite sides of the tubular member 41 in the axial direction of the tubular member 41. Further, the "radial direction" refers to a direction orthogonal to the axial direction of the tubular member 41.

[0080] <Thrust bearing 53>

[0081] As Figure 2As shown, the centrifugal compressor 10 includes a thrust bearing 53. The thrust bearing 53 is housed in a thrust bearing housing 19. The thrust bearing 53 includes a first thrust bearing portion 53a and a second thrust bearing portion 53b. The first thrust bearing portion 53a and the second thrust bearing portion 53b are arranged such that a support portion 48 is clamped into them. The first thrust bearing portion 53a is located relative to the support portion 48 near the compressor impeller 49. The second thrust bearing portion 53b is located relative to the support portion 48 near the first radial bearing 51.

[0082] Furthermore, the first thrust bearing portion 53a and the second thrust bearing portion 53b support the support portion 48 so that it can rotate in the thrust direction. Therefore, the thrust bearing 53 supports the rotor 33 between the compressor impeller 49 and the first radial bearing 51 via the support portion 48 so that it can rotate in the thrust direction. In addition, "thrust direction" refers to the direction parallel to the axial direction of the cylinder member 41. In this way, the rotor 33 is supported by the housing 11 so that it can rotate.

[0083] <Fuel Cell Systems 55>

[0084] like Figure 1 As shown, the centrifugal compressor 10 configured above constitutes part of the fuel cell system 55 mounted on a fuel cell vehicle. In addition to the centrifugal compressor 10, the fuel cell system 55 also 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 multiple battery cells (not shown). The supply flow path 57 connects the discharge chamber 24 to the fuel cell stack 56. The discharge flow path 58 connects the fuel cell stack 56 to the turbine vortex flow path 29.

[0085] As rotor 33 rotates, compressor impeller 49 and turbine impeller 50 rotate integrally with rotor 33. Therefore, motor 31 causes compressor impeller 49 to rotate. As compressor impeller 49 rotates, air is drawn into impeller chamber 23 from suction port 22. Furthermore, the air flowing through suction port 22 is purified by an air filter (not shown).

[0086] Air drawn in through intake 22 is compressed by compressor impeller 49 within impeller chamber 23 and discharged as compressed air from discharge chamber 24 to supply flow path 57 via compressor diffusion flow path 25. The air discharged from discharge chamber 24 to supply flow path 57 is then supplied to fuel cell stack 56 via supply flow path 57. The air supplied to fuel cell stack 56 is used to generate electricity. The air passing through fuel cell stack 56 is then discharged as exhaust gas from fuel cell stack 56 to exhaust flow path 58.

[0087] The exhaust gas of the fuel cell stack 56 is drawn into the turbine scroll passage 29 via the exhaust passage 58. The exhaust gas of 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 impeller 50 is rotated by the exhaust gas of the fuel cell stack 56 introduced into the turbine chamber 28. The rotor 33 is rotated by the rotation of the turbine impeller 50 rotated by the exhaust gas of the fuel cell stack 56 in addition to the rotation based on the driving of the motor 31. Also, the rotation of the rotor 33 is assisted by the rotation of the turbine impeller 50 based on the exhaust gas of 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.

[0088] <shaft passage 60>

[0089] The rotor 33 is provided with a shaft passage 60. The shaft passage 60 has a first shaft passage 61, a second shaft passage 62, and a third shaft passage 63. The first shaft passage 61 penetrates the inside of the first shaft member 44 in the axial direction of the first shaft member 44. The first shaft passage 61 is a circular hole. A first end of the first shaft passage 61 is open at the second end portion of the first shaft member 44 and communicates with the suction port 22.

[0090] The second shaft passage 62 penetrates the inside of the permanent magnet 42 in the axial direction of the permanent magnet 42. Thus, the shaft passage 60 penetrates the inside of the permanent magnet 42. The second shaft passage 62 is a circular hole. A first end of the second shaft passage 62 communicates with a second end of the first shaft passage 61. The axis of the second shaft passage 62 coincides with the axis of the first shaft passage 61.

[0091] The third shaft passage 63 extends in the axial direction of the second shaft member 45 in the inside of the second shaft member 45. The third shaft passage 63 is a circular hole. A first end of the third shaft passage 63 communicates with a second end of the second shaft passage 62. The axis of the third shaft passage 63 coincides with the axis of the second shaft passage 62. A second end of the third shaft passage 63 is located in the inside of the second shaft member 45.

[0092] Thus, the shaft passage 60 extends in the axial direction of the cylinder member 41 in the inside of the first shaft member 44, in the inside of the permanent magnet 42, and in the inside of the second shaft member 45. Thus, the shaft passage 60 extends in the axial direction of the rotor 33 in the inside of the rotor 33. Also, the shaft passage 60 is open at one end on the side of the compressor impeller 49 of the first shaft member 44 and communicates with the suction port 22.

[0093] <radial passage 70>

[0094] As Figure 5As shown, the rotor 33 has a plurality of paths 70. The plurality of paths 70 communicate with the second end of the third shaft path 63. Therefore, each path 70 communicates with the shaft path 60. Each path 70 extends from the third shaft path 63 toward the outer peripheral surface of the second shaft member 45. Therefore, each path 70 extends from the shaft path 60 toward the outer peripheral surface of the second shaft member 45. The first end of each path 70 communicates with the third shaft path 63. The second end of each path 70 opens into the outer peripheral surface of the second shaft member 45 and communicates with the motor chamber 18. Specifically, the second end of each path 70 communicates with a space within the motor chamber 18 that is radially inward of the second resin portion 39. The second end of each path 70 becomes an opening 71 that opens into the outer peripheral surface of the second shaft member 45. Therefore, each path 70 has an opening 71 that opens into the outer peripheral surface of the second shaft member 45.

[0095] Each path 70 extends in the direction of exiting the permanent magnet 42 from the third axis path 63, i.e., from axis path 60. The surface of each path 70 located radially outward of the second axis member 45 becomes a cover surface 72 that curves in an arc in the direction of exiting the permanent magnet 42 from the third axis path 63. Furthermore, the surface of each path 70 located radially inward of the second axis member 45 becomes a hub surface 73 that curves in an arc in the direction of exiting the permanent magnet 42 from the third axis path 63. The hub surface 73 extends along the cover surface 72. The hub surface 73 gradually approaches the cover surface 72 as it exits the third axis path 63. Therefore, the axial distance of each path 70 from the second axis member 45 gradually decreases towards the radially outward direction of the second axis member 45.

[0096] like Figure 6 As shown, the second shaft member 45 has a plurality of wing walls 74. Each wing wall 74 separates adjacent circumferential paths 70 of the second shaft member 45 from each other. The circumferential width of each wing wall 74 of the second shaft member 45 gradually increases toward the radially outward side of the second shaft member 45.

[0097] like Figure 7 As shown, the second shaft member 45 has a core 75. The core 75 supports each wing wall 74. The core 75 is cylindrical. The axis of the core 75 is aligned with the axis of the third shaft path 63. The end of each wing wall 74 located radially inward of the second shaft member 45 is continuous with the outer peripheral surface of the core 75. Each wing wall 74 extends in the tangential direction to the outer peripheral surface of the core 75. The outer diameter of the core 75 is smaller than the inner diameter of the third shaft path 63. Therefore, the end of each wing wall 74 located radially inward of the second shaft member 45 faces inward into the third shaft path 63. Consequently, the first end of each path 70 communicates with the third shaft path 63.

[0098] like Figure 6As shown, the outer peripheral surface of the second shaft member 45 has a plurality of intervening surfaces 76. Each intervening surface 76 is located between the openings 71 of adjacent paths 70 in the circumferential direction of the second shaft member 45. Each intervening surface 76 is an outer surface of each wing wall 74 located radially outward of the second shaft member 45. The circumferential distance of each path 70 in the second shaft member 45 gradually increases towards the radially outward direction of the second shaft member 45. Therefore, the opening 71 of each path 70 is the part with the longest circumferential distance in the second shaft member 45 among all paths 70. Furthermore, the circumferential length H1 of the second shaft member 45 in the intervening surface 76 is shorter than the circumferential length H2 of the second shaft member 45 in the opening 71.

[0099] like Figure 1 As shown, air from the intake port 22 is introduced into the first end of the first shaft path 61. Furthermore, the air introduced from the intake port 22 into the first shaft path 61 is introduced into the space, namely the introduction space 77, in the motor chamber 18 that is radially inward from the second resin section 39 via the first shaft path 61, the second shaft path 62, the third shaft path 63, and each path 70.

[0100] <Diffusion Path 78>

[0101] like Figure 4 As shown, the centrifugal compressor 10 includes a diffusion flow path 78. The diffusion flow path 78 is a space formed between the inner circumferential surface of the third resin section 40 and the outer circumferential surface of the cylinder member 41. Therefore, the diffusion flow path 78 is disposed between the stator 32 and the rotor 33. The diffusion flow path 78 connects the inlet space 77 to the outlet space 79 in the motor chamber 18, which is located radially inward from the first resin section 38. The diffusion flow path 78 is narrowed in such a way that the cross-sectional area of ​​the flow path closest to the inlet space 77 is minimized. The cross-sectional area of ​​the flow path 78 closest to the outlet space 79 is maximized. Therefore, the cross-sectional area of ​​the flow path 78 gradually increases from the inlet space 77 towards the outlet space 79. Furthermore, the diffusion flow path 78 pressurizes the air from the inlet space 77. Therefore, the diffusion flow path 78 pressurizes the air introduced into the motor chamber 18 from each path 70.

[0102] <Discharge outlet 80>

[0103] like Figure 2 As shown, the housing 11 has an outlet 80. The outlet 80 is formed in the first plate 15. The outlet 80 is located closer to the impeller chamber 23 than the motor chamber 18. The outlet 80 extends radially along the cylindrical member 41 inside the first plate 15. The first end of the outlet 80 opens on the outer peripheral surface of the first plate 15. The second end of the outlet 80 is located inside the first plate 15. The outlet 80 discharges air introduced into the motor chamber 18 from the suction port 22 via the shaft path 60 and various paths 70 to the outside of the housing 11.

[0104] The housing 11 has a first discharge passage 81, a second discharge passage 82, a third discharge passage 83, and a fourth discharge passage 84. The first discharge passage 81 extends through the interior of the first plate 15. The first discharge passage 81 connects the interior of the first radial bearing retaining portion 21 to the discharge port 80. The first end of the first discharge passage 81 communicates with the interior of the first radial bearing retaining portion 21. The second end of the first discharge passage 81 communicates with the discharge port 80. The first discharge passage 81 allows air inside the first radial bearing retaining portion 21 to flow toward the discharge port 80.

[0105] The second discharge passage 82 extends through the interior of the first plate 15. The second discharge passage 82 connects the motor chamber 18 to the thrust bearing housing chamber 19. The first end of the second discharge passage 82 communicates with the space within the motor chamber 18 near the first plate 15, where the stator 32 is located. The second end of the second discharge passage 82 opens onto the inner circumferential surface of the second recess 15d. Furthermore, the second end of the second discharge passage 82 communicates with the thrust bearing housing chamber 19. The second discharge passage 82 allows air within the motor chamber 18 to flow towards the thrust bearing housing chamber 19.

[0106] The third discharge path 83 penetrates the interior of the sealing plate 17 and the interior of the first plate 15. The third discharge path 83 connects the shaft insertion through-hole 17h to the discharge outlet 80. The first end of the third discharge path 83 communicates with the interior of the shaft insertion through-hole 17h. The second end of the third discharge path 83 communicates with the discharge outlet 80. Therefore, the third discharge path 83 is connected to the thrust bearing housing chamber 19 via the shaft insertion through-hole 17h. The third discharge path 83 allows air within the thrust bearing housing chamber 19 to flow from the wall of the thrust bearing housing chamber 19 near the first thrust bearing portion 53a toward the discharge outlet 80.

[0107] like Figure 1 As shown, the fourth discharge path 84 passes through the second plate 16 and the motor housing 12. The fourth discharge path 84 connects the shaft insertion through hole 16h to the discharge port 80. The first end of the fourth discharge path 84 is connected to the shaft insertion through hole 16h. The second end of the fourth discharge path 84 is connected to the discharge port 80. The fourth discharge path 84 causes the air in the shaft insertion through hole 16h to flow towards the discharge port 80.

[0108] [Effect of the first embodiment]

[0109] Next, the function of the first embodiment will be explained.

[0110] A portion of the air from the intake 22 is introduced into the shaft path 60 and flows through the shaft path 60 and each of the paths 70. The air flowing in each of the paths 70 is introduced into the introduction space 77 within the motor chamber 18. The permanent magnet 42 is cooled by the air flowing in the shaft path 60. Thus, the permanent magnet 42 is cooled by air that is colder than the compressed air.

[0111] A portion of the air introduced from each passage 70 into the introduction space 77 passes through the inside of the 2nd radial bearing holding portion 26. The 2nd radial bearing 52 is cooled by the air passing through the inside of the 2nd radial bearing holding portion 26. The air that has passed through the inside of the 2nd radial bearing holding portion 26 is discharged from the discharge port 80 to the outside of the motor chamber 18 via the shaft insertion hole 16h and the 4th discharge passage 84.

[0112] In addition, a portion of the air introduced from each passage 70 into the introduction space 77 is boosted by the diffusion passage 78 while flowing toward the discharge space 79. A portion of the air discharged from the diffusion passage 78 to the discharge space 79 passes through the inside of the 1st radial bearing holding portion 21. The 1st radial bearing 51 is cooled by the air passing through the inside of the 1st radial bearing holding portion 21. The air that has passed through the inside of the 1st radial bearing holding portion 21 is discharged from the discharge port 80 to the outside of the motor chamber 18 via the 1st discharge passage 81. In this way, the air that has passed through the diffusion passage 78 in the motor chamber 18 passes through the inside of the 1st radial bearing holding portion 21, and is then discharged from the discharge port 80 to the outside of the motor chamber 18 via the 1st discharge passage 81. The diffusion passage 78 boosts the air introduced from each passage 70 into the motor chamber 18 and causes it to flow toward the discharge port 80.

[0113] In addition, a portion of the air discharged from the diffusion passage 78 to the discharge space 79 flows from a space in the motor chamber 18 closer to the 1st plate 15 than the stator 32 into the thrust bearing housing chamber 19 via the 2nd discharge passage 82. Also, the air that has flowed into the thrust bearing housing chamber 19 is branched into air that flows toward the 1st thrust bearing portion 53a and air that flows toward the 2nd thrust bearing portion 53b.

[0114] The air that flows toward the 1st thrust bearing portion 53a is discharged from the discharge port 80 to the outside of the motor chamber 18 via the 3rd discharge passage 83. The 1st thrust bearing portion 53a is cooled by the air that flows toward the 1st thrust bearing portion 53a in the thrust bearing housing chamber 19. Also, the thrust bearing housing chamber 19 communicates with the 1st radial bearing holding portion 21. Therefore, the air that flows toward the 2nd thrust bearing portion 53b flows into the 1st radial bearing holding portion 21, and is discharged from the discharge port 80 to the outside of the motor chamber 18 via the 1st discharge passage 81. The 2nd thrust bearing portion 53b is cooled by the air that flows toward the 2nd thrust bearing portion 53b in the thrust bearing housing chamber 19.

[0115] The circumferential distance of the second shaft member 45 of each path 70 gradually becomes longer toward the radially outer side of the second shaft member 45. Therefore, the air flowing in each path 70 easily flows in each path 70 toward the radially outer side of the second shaft member 45 by the centrifugal force accompanying the rotation of the second shaft member 45. In particular, each path 70 extends in a direction away from the shaft path 60 and away from the permanent magnet 42 as it moves away from the shaft path 60. Also, the axial distance of the second shaft member 45 of each path 70 gradually becomes shorter toward the radially outer side of the second shaft member 45. Thus, the air flowing in each path 70 is easily compressed by the centrifugal force accompanying the rotation of the second shaft member 45. Therefore, a portion of the air from the suction port 22 is easily drawn toward the shaft path 60.

[0116] As shown in Figure 6 , the length H1 of the second shaft member 45 in the circumferential direction of the intervening face 76 is shorter than the length H2 of the second shaft member 45 in the circumferential direction of the opening portion 71 of each path 70. Thus, the air remaining in the motor chamber 18 in the vicinity of the intervening face 76 is relatively small. Therefore, the flow of the air introduced from each path 70 into the motor chamber 18 can be inhibited from being impeded by the air remaining in the motor chamber 18 in the vicinity of the intervening face 76. As a result, a portion of the air from the suction port 22 is easily introduced into the motor chamber 18 via the shaft path 60 and each path 70, and thus the air easily flows in the shaft path 60. Therefore, the permanent magnet 42 is efficiently cooled.

[0117] [Effects of the First Embodiment]

[0118] The following effects can be obtained in the first embodiment.

[0119] (1-1) The circumferential distance of the second shaft member 45 of each path 70 gradually becomes longer toward the radially outer side of the second shaft member 45. Therefore, the air flowing in each path 70 easily flows in each path 70 toward the radially outer side of the second shaft member 45 by the centrifugal force accompanying the rotation of the second shaft member 45. Also, the length H1 of the second shaft member 45 in the circumferential direction of the intervening face 76 is shorter than the length H2 of the second shaft member 45 in the circumferential direction of the opening portion 71 of each path 70. Thus, the air remaining in the motor chamber 18 in the vicinity of the intervening face 76 can be made relatively small. Therefore, the flow of the air introduced from each path 70 into the motor chamber 18 can be inhibited from being impeded by the air remaining in the motor chamber 18 in the vicinity of the intervening face 76. As a result, a portion of the air from the suction port 22 is easily introduced into the motor chamber 18 via the shaft path 60 and each path 70, and thus the air easily flows in the shaft path 60. Therefore, the permanent magnet 42 can be efficiently cooled.

[0120] (1-2) Each of the radial passages 70 extends in a direction away from the permanent magnet 42 as it departs from the shaft passage 60. Thus, the air flowing in each of the radial passages 70 is easily compressed by the centrifugal force accompanying the rotation of the second shaft member 45. Therefore, a portion of the air from the suction port 22 is easily drawn toward the shaft passage 60. As a result, the air is more easily drawn in the shaft passage 60. Thus, the permanent magnet 42 can be more efficiently cooled.

[0121] (1-3) The distance of the second shaft member 45 in the axial direction of each of the radial passages 70 gradually shortens as it goes toward the radially outer side of the second shaft member 45. Thus, the air flowing in each of the radial passages 70 is more easily compressed by the centrifugal force accompanying the rotation of the second shaft member 45. Therefore, a portion of the air from the suction port 22 is more easily drawn toward the shaft passage 60. As a result, the air is more easily drawn in the shaft passage 60. Thus, the permanent magnet 42 can be more efficiently cooled.

[0122] (1-4) The centrifugal compressor 10 is provided with a diffusion flow path 78 that pressurizes the air introduced from each of the radial passages 70 into the motor chamber 18 and causes it to flow toward the discharge port 80. Thus, the air introduced from each of the radial passages 70 into the motor chamber 18 is pressurized by the diffusion flow path 78 while flowing toward the discharge port 80, and is discharged from the discharge port 80. Therefore, the air introduced from each of the radial passages 70 into the motor chamber 18 is easily discharged via the discharge port 80. As a result, a portion of the air from the suction port 22 is easily drawn toward the shaft passage 60. As a result, the air is more easily drawn in the shaft passage 60. Thus, the permanent magnet 42 can be more efficiently cooled.

[0123] [Second Embodiment]

[0124] Hereinafter, the second embodiment that embodies the centrifugal compressor will be described in accordance with Figures 8-12 The second embodiment that embodies the centrifugal compressor will be described. Also, in the embodiment described below, the same reference numerals are assigned to the same configurations as those of the first embodiment already described, and the repeated description thereof will be omitted or simplified. In the second embodiment, the shaft passage and the radial passage are provided in the first shaft member 44, unlike the first embodiment in which the shaft passage 87 and the radial passage 98 are provided in the second shaft member 45. Also, in the second embodiment, the shaft passage 87 does not pass through the inside of the permanent magnet 42 as in the first embodiment. Also, in the second embodiment, the centrifugal compressor 10 is not provided with the diffusion flow path as in the first embodiment.

[0125] As Figure 8 and Figure 9As shown, the first shaft member 44 has a tube portion 85 and an impeller portion 86. The tube portion 85 passes through the compressor impeller 49. The first end of the tube portion 85 protrudes from the top surface of the compressor impeller 49. The inner side of the tube portion 85 forms a shaft path 87. Therefore, the tube portion 85 forms a shaft path 87. Thus, a shaft path 87 is provided in the first shaft member 44. The rotor 33 has a shaft path 87.

[0126] The axis of the shaft passage 87 is aligned with the axis of the tube section 85. The first end of the shaft passage 87 opens at the first end face of the tube section 85. Therefore, the shaft passage 87 opens at one end of the first shaft member 44 on the compressor impeller 49 side and communicates with the suction port 22. Furthermore, the shaft passage 87 extends axially along the rotor 33 inside the rotor 33.

[0127] like Figure 10 As shown, the tube portion 85 has a cover surface 88. The cover surface 88 is continuous with the second end of the shaft path 87. Therefore, the cover surface 88 is continuous with the end of the shaft path 87 opposite to the suction port 22. The cover surface 88 extends in a direction that moves away from the suction port 22 as it leaves the shaft path 87. The cover surface 88 is an arc-shaped curved surface that convexes toward the axis of the tube portion 85.

[0128] The tube 85 has a mounting hole 89. The mounting hole 89 extends axially along the rotor 33. The axis of the mounting hole 89 is aligned with the axis of the tube 85. The first end of the mounting hole 89 is continuous with the end of the cover 88 opposite to the shaft path 87. The cover 88 connects the inner circumferential surface of the tube 85 forming the shaft path 87 to the inner circumferential surface of the mounting hole 89. The diameter of the mounting hole 89 is larger than the diameter of the shaft path 87. The second end of the mounting hole 89 opens at the second end face of the tube 85.

[0129] The tube portion 85 has a plurality of radial holes 90. Each radial hole 90 extends radially along the tube portion 85. Each radial hole 90 is square-shaped. A first end of each radial hole 90 opens into the inner peripheral surface of the mounting hole 89. A portion of the opening edge of the first end of each radial hole 90 is continuous with the end in the cover surface 88 opposite to the shaft path 87. A second end of each radial hole 90 opens into the outer peripheral surface of the tube portion 85. Furthermore, the second end of each radial hole 90 communicates with the motor chamber 18. Specifically, the second end of each radial hole 90 communicates with a space within the motor chamber 18 that is radially inward from the end 36a of the first coil. Each radial hole 90 extends from the inner peripheral surface of the mounting hole 89 toward the outer peripheral surface of the tube portion 85 and communicates with the motor chamber 18.

[0130] like Figure 11 As shown, the circumferential distance between the pipe portions 85 of each bore 90 gradually increases towards the radially outward side of the pipe portion 85. The pipe portion 85 has a plurality of intermediate walls 91. Each intermediate wall 91 is located between adjacent bores 90 in the circumferential direction of the pipe portion 85. The circumferential width of each pipe portion 85 with intermediate walls 91 gradually increases towards the radially outward side of the pipe portion 85.

[0131] As shown in Figure 10 The pipe portion 85 has a plurality of internally threaded holes 92. Each of the internally threaded holes 92 extends in the radial direction of the pipe portion 85. A first end of each of the internally threaded holes 92 is open in the inner peripheral surface of the mounting hole 89. Specifically, the first end of each of the internally threaded holes 92 is open in a portion of the inner peripheral surface of the mounting hole 89 that is closer to the second end surface of the pipe portion 85 than the opening position of each of the radial holes 90. A second end of each of the internally threaded holes 92 is open in the outer peripheral surface of the pipe portion 85. Specifically, the second end of each of the internally threaded holes 92 is open in a portion of the outer peripheral surface of the pipe portion 85 that is closer to the second end surface of the pipe portion 85 than the opening position of each of the radial holes 90.

[0132] The impeller portion 86 has a hub portion 93 and a mounting portion 94. The hub portion 93 is cylindrical. The hub portion 93 has a hub surface 95. The hub surface 95 extends along the cover surface 88. The hub surface 95 is an arcuately curved surface that is concave toward the axis of the hub portion 93. The hub surface 95 gradually approaches the cover surface 88 as it departs from the shaft passage 87. The mounting portion 94 is cylindrical. The mounting portion 94 is inserted into the mounting hole 89. A portion of the mounting portion 94 protrudes from the mounting hole 89.

[0133] As shown in Figure 10 and Figure 11 The impeller portion 86 has a plurality of wing walls 96. Each of the wing walls 96 rises from the hub surface 95. Each of the wing walls 96 extends from the hub surface 95 toward the cover surface 88. An outer edge of each of the wing walls 96 on the cover surface 88 side extends along the cover surface 88. The outer edge of each of the wing walls 96 on the cover surface 88 side is in contact with the cover surface 88.

[0134] As shown in Figure 11 The two side surfaces of each of the wing walls 96 at positions on both sides in the circumferential direction of the impeller portion 86 are on the same plane as the two side surfaces of each of the intervening walls 91 at positions on both sides in the circumferential direction of the pipe portion 85. Spaces between wing walls 96 adjacent in the circumferential direction of the impeller portion 86, which are spaces between the cover surface 88 and the hub surface 95, communicate with each of the radial holes 90.

[0135] As shown in Figure 10 A threaded member 97 is threadedly engaged with each of the internally threaded holes 92. Also, each of the threaded members 97 that is threadedly engaged with each of the internally threaded holes 92 is in abutment with the outer peripheral surface of the mounting portion 94, whereby the pipe portion 85 and the impeller portion 86 are fixed to each other via each of the threaded members 97. Thus, the pipe portion 85 and the impeller portion 86 are integrated via each of the threaded members 97, thereby constituting the first shaft member 44. The portion of the mounting portion 94 that protrudes from the mounting hole 89 is inserted inside the first end portion of the cylinder member 41. Also, the mounting portion 94 is press-fitted to the inner peripheral surface of the first end portion of the cylinder member 41. Thus, the first shaft member 44 is fixed to the cylinder member 41.

[0136] The rotor 33 has a plurality of radial passages 98. Each radial passage 98 is formed by the space between the wing walls 96 adjacent in the circumferential direction of the impeller portion 86, which are spaces between the shroud surface 88 and the hub surface 95, and the radial holes 90.

[0137] As shown in Fig. 2, the end portion of each wing wall 96 at a position radially inside the first shaft member 44 faces into the axial passage 87. Thus, the first end of each radial passage 98 communicates with the second end of the axial passage 87. Each radial passage 98 communicates with the axial passage 87 and extends from the axial passage 87 toward the outer peripheral surface of the first shaft member 44. Figure 12 As shown in Fig. 2, the second end of each radial passage 98 opens at the outer peripheral surface of the tube portion 85, communicating with the inside of the motor chamber 18. Thus, each radial passage 98 has an opening portion 99 that opens at the outer peripheral surface of the tube portion 85. Therefore, the opening portion 99 opens at the outer peripheral surface of the first shaft member 44. The opening portion 99 of each radial passage 98 is the portion of each radial hole 90 that opens at the outer peripheral surface of the tube portion 85.

[0138] Figure 10 As shown in Fig. 2, the outer peripheral surface of the first shaft member 44 has intervening surfaces 100 that intervene between the opening portions 99 of the radial passages 98 adjacent in the circumferential direction of the first shaft member 44. Each intervening surface 100 is the outer surface of each intervening wall 91 of the tube portion 85.

[0139] As shown in Fig. 2, the distance in the circumferential direction of the first shaft member 44 of each radial passage 98 gradually becomes longer as it goes toward the radially outside of the first shaft member 44. Therefore, the opening portion 99 of each radial passage 98 is the portion of each radial passage 98 in which the distance in the circumferential direction of the first shaft member 44 is the longest. Also, the length Hl l in the circumferential direction of the first shaft member 44 of the intervening surface 100 is shorter than the length H12 in the circumferential direction of the first shaft member 44 of the opening portion 99. Figure 11 As shown in Fig. 2, each radial passage 98 extends in a direction that moves away from the suction port 22 as it moves away from the axial passage 87. The distance in the axial direction of the first shaft member 44 of each radial passage 98 gradually becomes shorter as it goes toward the radially outside of the first shaft member 44. The plurality of radial passages 98 extend in the radial direction of the first shaft member 44 and communicate with the inside of the motor chamber 18. Each radial passage 98 communicates with the space inside the motor chamber 18 that is radially inside the first coil end 36a. Also, the plurality of radial passages 98 introduce air introduced from the suction port 22 into the axial passage 87 into the inside of the motor chamber 18.

[0140] [Effects of the Second Embodiment]

[0141] Figure 10 Next, the effects of the second embodiment will be described.

[0142] [Effects of the Second Embodiment]

[0143] Next, the effects of the second embodiment will be described.

[0144] ​​A portion of the air from the intake 22 is introduced into the shaft path 87 and flows through the shaft path 87 and each path 98. The air flowing in each path 98 is introduced into the motor chamber 18. The permanent magnet 42 is cooled by the air introduced into the motor chamber 18. The air introduced into the motor chamber 18 is at a lower temperature than the compressed air. Therefore, the permanent magnet 42 is cooled efficiently.

[0145] The circumferential distance of the first shaft member 44 in each path 98 gradually increases towards the radially outward direction of the first shaft member 44. Therefore, air flowing within each path 98 is easily drawn towards the radially outward direction of the first shaft member 44 by the centrifugal force accompanying the rotation of the first shaft member 44. In particular, each path 98 extends in the direction of exiting the shaft passage 87 and exiting the intake port 22. Furthermore, the axial distance of the first shaft member 44 in each path 98 gradually decreases towards the radially outward direction of the first shaft member 44. Therefore, air flowing in each path 98 is easily compressed by the centrifugal force accompanying the rotation of the first shaft member 44. Consequently, a portion of the air from the intake port 22 is easily drawn in towards the shaft passage 87.

[0146] like Figure 11 As shown, the circumferential length H11 of the first shaft member 44 on the surface 100 is shorter than the circumferential length H12 of the first shaft member 44 at the opening 99 of each path 98. Therefore, less air is retained in the motor chamber 18 near the surface 100. Consequently, the flow of air introduced into the motor chamber 18 from each path 98 is hindered by the air retained in the motor chamber 18 near the surface 100. As a result, a portion of the air from the intake port 22 is easily introduced into the motor chamber 18 via the shaft path 87 and each path 98. Therefore, the permanent magnet 42 is cooled efficiently.

[0147] [Effects of the second implementation method]

[0148] The following effects can be obtained in the second embodiment.

[0149] (2-1) The circumferential distance of the first shaft member 44 in each path 98 gradually increases towards the radially outer side of the first shaft member 44. Therefore, air flowing in each path 98 is easily propelled radially outward from the first shaft member 44 by the centrifugal force accompanying the rotation of the first shaft member 44. Furthermore, the circumferential length H11 of the first shaft member 44 on the surface 100 is shorter than the circumferential length H12 of the first shaft member 44 at the opening 99 of each path 98. Therefore, less air is retained in the motor chamber 18 near the surface 100. Thus, the flow of air introduced from each path 98 into the motor chamber 18 is prevented from being obstructed by air retained in the motor chamber 18 near the surface 100. As a result, a portion of the air from the intake port 22 is easily introduced into the motor chamber 18 via the shaft path 87 and each path 98. Therefore, the permanent magnet 42 can be cooled efficiently.

[0150] (2-2) Each path 98 extends in the direction of exiting from the shaft path 87 and exiting from the intake port 22. Therefore, the air flowing in each path 98 is easily compressed by the centrifugal force accompanying the rotation of the first shaft member 44. Consequently, a portion of the air from the intake port 22 is easily drawn towards the shaft path 87. Thus, air is easily introduced into the motor chamber 18. Therefore, the permanent magnet 42 can be cooled more efficiently.

[0151] (2-3) The axial distance between the first shaft members 44 of each path 98 gradually decreases towards the radially outer side of the first shaft member 44. Therefore, the air flowing in each path 98 is more easily compressed by the centrifugal force accompanying the rotation of the first shaft member 44. Consequently, a portion of the air from the intake port 22 is more easily drawn into the shaft path 87. Thus, air is more easily introduced into the motor chamber 18. Therefore, the permanent magnet 42 can be cooled more efficiently.

[0152] [Example of Change]

[0153] Furthermore, the above embodiments can be modified as follows. The above embodiments and the following modifications can be combined with each other within the scope of technical non-contradiction.

[0154] like Figure 13 As shown, in the second embodiment, the centrifugal compressor 10 may also include a partition wall 101. The resin section 37 has a partition wall 101. The partition wall 101 is an annular structure protruding from the resin section 37 at a portion slightly closer to the first radial bearing holding portion 21 than the portion overlapping the openings 99 of each path 98 in the radial direction of the first shaft member 44. The partition wall 101 guides air introduced into the motor chamber 18 from each path 98 toward the space between the stator 32 and the rotor 33.

[0155] Thus, the air introduced into the motor chamber 18 from each passage 98 is guided by the partition wall 101 toward between the stator 32 and the rotor 33. Therefore, the air introduced into the motor chamber 18 from each passage 98 easily flows between the stator 32 and the rotor 33, and thus the permanent magnets 42 can be more efficiently cooled by the air flowing between the stator 32 and the rotor 33.

[0156] In the first embodiment, each passage 70 can also extend from the shaft passage 60 in the radial direction of the second shaft member 45. For example, a plurality of passages 70 can also extend radially from the third shaft passage 63 with the axis of the third shaft passage 63 as the center. In any case, each passage 70 can also not extend in a direction in which the permanent magnets 42 depart from the shaft passage 60 as they depart from the second shaft member 45.

[0157] In the second embodiment, each passage 98 can also extend from the shaft passage 87 in the radial direction of the first shaft member 44. For example, a plurality of passages 98 can also extend radially from the shaft passage 87 with the axis of the shaft passage 87 as the center. In any case, each passage 98 can also not extend in a direction in which the permanent magnets 42 depart from the shaft passage 87 as they depart from the suction port 22.

[0158] In the first embodiment, for example, each passage 70 can also extend from the shaft passage 60 toward the outer peripheral surface of the second shaft member 45 in a state in which the distance in the axial direction of the second shaft member 45 of each passage 70 is constant. In any case, the distance in the axial direction of the second shaft member 45 of each passage 70 can also not gradually shorten as it goes toward the radial outside of the second shaft member 45.

[0159] In the second embodiment, for example, each passage 98 can also extend from the shaft passage 87 toward the outer peripheral surface of the first shaft member 44 in a state in which the distance in the axial direction of the first shaft member 44 of each passage 98 is constant. In any case, the distance in the axial direction of the first shaft member 44 of each passage 98 can also not gradually shorten as it goes toward the radial outside of the first shaft member 44.

[0160] In the first embodiment, the distance in the axial direction of the second shaft member 45 of each passage 70 can also gradually lengthen as it goes toward the radial outside of the second shaft member 45.

[0161] In the second embodiment, the distance in the axial direction of the first shaft member 44 of each passage 98 can also gradually lengthen as it goes toward the radial outside of the first shaft member 44.

[0162] In each of the above embodiments, the discharge port 80 can also be formed in the peripheral wall 12b of the motor housing 12, for example. Also, the discharge port 80 can also communicate with a space in the motor chamber 18 that is closer to the first plate 15 than the stator 32. In this case, the first discharge passage 81, the second discharge passage 82, and the third discharge passage 83 can also not be formed in the housing 11.

[0163] In the first embodiment, the inner peripheral surface of the stator core 34 can also not be covered with resin. Also, the inner peripheral surface of the stator core 34 can be a conical hole in which the inner diameter gradually expands as it goes from the second coil end 36b toward the first coil end 36a. In this way, a diffusion flow path 78 can also be formed between the inner peripheral surface of the stator core 34 and the outer peripheral surface of the cylinder member 41.

[0164] In the first embodiment, the inner diameter of the inner peripheral surface of the third resin portion 40 can also be constant. Also, the outer peripheral surface of the cylinder member 41 can be a conical surface in which the outer diameter gradually expands as it goes from the second shaft member 45 toward the first shaft member 44. Also, a diffusion flow path 78 can be formed between the inner peripheral surface of the third resin portion 40 and the outer peripheral surface of the cylinder member 41. In any case, the diffusion flow path 78 is provided between the stator 32 and the rotor 33.

[0165] In the first embodiment, the centrifugal compressor 10 can also be a configuration that does not have a diffusion flow path 78.

[0166] In each of the above embodiments, the permanent magnet 42 can also be, for example, not pressed into the inner peripheral surface of the cylinder member 41, but rather, for example, bonded to the inner peripheral surface of the cylinder member 41 by an adhesive. In any case, the permanent magnet 42 is fixed to the inside of the cylinder member 41.

[0167] In each of the above embodiments, the centrifugal compressor 10 can also be a configuration that does not have a turbine wheel 50.

[0168] In each of the above embodiments, the centrifugal compressor 10 can also be a configuration that has a compressor wheel instead of the turbine wheel 50. That is, the centrifugal compressor 10 can also be a configuration in which compressor wheels are attached to the first shaft member 44 and the second shaft member 45, respectively, and in which air compressed by one of the compressor wheels is compressed again by the other compressor wheel.

[0169] In each of the above embodiments, as the magnetic body, the permanent magnet 42 is not limiting, and for example, a laminated core, an amorphous core, or a dust core, etc. can also be used.

[0170] In each of the above embodiments, the cylinder member 41 can also be composed of, for example, carbon fiber reinforced plastic. In any case, the material of the cylinder member 41 is not particularly limited.

[0171] In each of the above embodiments, the centrifugal compressor 10 can also not be mounted on a fuel cell vehicle. In any case, the centrifugal compressor 10 is not limited to being mounted on a vehicle.

Claims

1. A centrifugal compressor, comprising: a compressor impeller that compresses air; a motor that rotates the compressor impeller; and a casing that has an impeller chamber that houses the compressor impeller, a motor chamber that houses the motor, and a suction port that sucks air into the impeller chamber, the motor comprising: a stator that is fixed to the casing; and a rotor that is disposed inside the stator, the rotor comprising: a cylinder member; a magnetic body that is fixed to the inside of the cylinder member; and a first shaft member and a second shaft member that are disposed on both sides of the magnetic body in the axial direction of the cylinder member, the compressor impeller being connected to the first shaft member, the centrifugal compressor being characterized in that the rotor comprises: a shaft passage that opens at one end on the compressor impeller side of the first shaft member and communicates with the suction port and extends in the axial direction of the rotor inside the rotor; and a plurality of radial passages that communicate with the shaft passage and extend from the shaft passage toward the outer peripheral surface of the second shaft member and communicate with the motor chamber, the casing having a discharge port that discharges air introduced from the suction port into the motor chamber to the outside of the casing, the distance in the peripheral direction of the second shaft member of each radial passage gradually lengthening as it goes toward the radially outer side of the second shaft member, each radial passage having an opening portion that opens at the outer peripheral surface of the second shaft member, the outer peripheral surface of the second shaft member having an intervening surface that intervenes between the opening portions of adjacent radial passages in the peripheral direction of the second shaft member, the length in the peripheral direction of the second shaft member of the intervening surface being shorter than the length in the peripheral direction of the second shaft member of the opening portions.

2. The centrifugal compressor according to claim 1, wherein each radial passage extends in a direction that moves away from the magnetic body as it moves away from the shaft passage.

3. The centrifugal compressor according to claim 2, wherein the distance in the axial direction of the second shaft member of each radial passage gradually shortens as it goes toward the radially outer side of the second shaft member.

4. The centrifugal compressor according to any one of claims 1 to 3, comprising a diffusion flow path that is provided between the stator and the rotor and that pressurizes air introduced from each radial passage into the motor chamber and causes it to flow toward the discharge port.

5. A centrifugal compressor, comprising: a compressor impeller that compresses air; a motor that rotates the compressor impeller; and a casing that has an impeller chamber that houses the compressor impeller, a motor chamber that houses the motor, and a suction port that sucks air into the impeller chamber, the motor comprising: a stator that is fixed to the casing; and a rotor that is disposed inside the stator, the rotor comprising: a cylinder member; a magnetic body that is fixed to the inside of the cylinder member; and a first shaft member and a second shaft member that are disposed on both sides of the magnetic body in the axial direction of the cylinder member, the compressor impeller being connected to the first shaft member. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The compressor impeller is connected to the first shaft member, The centrifugal compressor is characterized by The rotor is provided with: a shaft passage that opens at one end on the compressor impeller side of the first shaft member and communicates with the suction port, and extends in the axial direction of the rotor inside the rotor; and a plurality of radial passages that communicate with the shaft passage and extend from the shaft passage toward the outer peripheral surface of the first shaft member and communicate with the motor chamber, The housing has a discharge port that discharges air introduced from the suction port into the motor chamber to the outside of the housing, The circumferential distance of the first shaft member of each radial passage gradually lengthens toward the radially outer side of the first shaft member, Each radial passage has an opening portion that opens at the outer peripheral surface of the first shaft member, The outer peripheral surface of the first shaft member has an intervening surface between the opening portions of adjacent radial passages in the circumferential direction of the first shaft member, The length of the circumferential direction of the first shaft member of the intervening surface is shorter than the length of the circumferential direction of the first shaft member of the opening portion.

6. The centrifugal compressor according to claim 5, characterized in that Each radial passage extends in a direction that moves away from the suction port as it moves away from the shaft passage.

7. The centrifugal compressor according to claim 6, characterized in that The axial distance of the first shaft member of each radial passage gradually shortens toward the radially outer side of the first shaft member.

8. The centrifugal compressor according to any one of claims 5 to 7, characterized in that The centrifugal compressor is provided with a partition wall that guides air introduced from each radial passage into the motor chamber toward between the stator and the rotor.

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