Centrifugal compressor

Abstract

To reduce a size of a centrifugal compressor.SOLUTION: Since a housing 11 is cooled by cooling water flowing in a cooling water passage 71, heat of air flowing on an inner side of a first recessed part 61 is efficiently released to the housing 11 via a plurality of cooling fins 62. As a result, air flowing in a fluid passage 60 is efficiently cooled. Thus a motor 20 is efficiently cooled by air supplied from the fluid passage 60. Accordingly, like conventional techniques, without using an intercooler, the motor 20 is cooled by using part of air compressed by rotating a second impeller. To close an opening of the first recessed part 61, resin 53 that is an existing configuration is used. Thus it is unnecessary to additionally provide a closing member for closing the opening of the first recessed part 61.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a centrifugal compressor.

Background Art

[0002] A centrifugal compressor includes a rotating shaft, an impeller, a motor, and a housing. The impeller rotates integrally with the rotating shaft to compress a fluid. The motor rotates the rotating shaft. The motor has a cylindrical stator. The housing partitions an impeller chamber and a motor chamber. The impeller chamber houses the impeller. The motor chamber houses the motor. The stator has a stator core and a coil end which is a part of a coil wound around the stator core. The coil end protrudes from an end face of the stator core. Also, the stator may have a resin for molding the coil end. And heat generated from the coil is radiated to the housing through the resin from the coil end.

[0003] By the way, in such a centrifugal compressor, in order to improve the durability of the centrifugal compressor, it is desired to cool the motor. Therefore, the housing may have a cooling water passage and a fluid passage. Cooling water for cooling the housing to cool the motor flows in the cooling water passage. A part of the fluid compressed by the rotation of the impeller for cooling the motor flows in the fluid passage.

[0004] Heat generated from the motor is radiated to the housing. At this time, since the housing is cooled by the cooling water flowing in the cooling water passage, the heat generated from the motor is efficiently radiated to the housing. As a result, the motor is efficiently cooled.

[0005] On the other hand, the fluid flowing through the fluid passage needs to be supplied to the motor at a temperature lower than the temperature of the fluid after it has been compressed by the rotation of the impeller, in order to cool the motor. Therefore, as disclosed in Patent Document 1, for example, it is known that the fluid after it has been compressed by the rotation of the impeller is cooled by an intercooler before being supplied to the motor through the fluid passage. In this way, the motor is cooled by the fluid supplied from the fluid passage. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-7026 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in this configuration, where an intercooler is used to cool the fluid after it has been compressed by the rotation of the impeller, the size of the centrifugal compressor increases due to the presence of the intercooler. Therefore, it is desirable to reduce the size of the centrifugal compressor by using a portion of the fluid compressed by the rotation of the impeller to cool the motor without using an intercooler. [Means for solving the problem]

[0008] A centrifugal compressor that solves the above problems comprises a rotating shaft, an impeller that rotates integrally with the rotating shaft to compress a fluid, a motor that rotates the rotating shaft and has a cylindrical stator, and a housing that partitions the impeller chamber that houses the impeller and the motor chamber that houses the motor, wherein the housing has a cooling water passage through which cooling water flows to cool the housing in order to cool the motor, and a fluid passage through which a portion of the fluid compressed by the rotation of the impeller flows in order to cool the motor, and the stator comprises a stator core and a portion of a coil wound around the stator core A centrifugal compressor having a coil end protruding from the end face of the stator core and a resin molding the coil end, wherein heat generated from the coil is dissipated from the coil end through the resin to the housing, wherein a first recess constituting part of the fluid passage is formed on the motor chamber side surface of the housing, a plurality of cooling fins protruding from the bottom surface of the first recess, the resin partitioning a part of the fluid passage together with the first recess by closing the opening of the first recess, and the fluid flowing inside the first recess is dissipated to the housing via the plurality of cooling fins.

[0009] According to this design, the housing is cooled by the cooling water flowing through the cooling water passage, and the fluid flowing inside the first recess efficiently dissipates heat to the housing via multiple cooling fins. As a result, the fluid flowing through the fluid passage is efficiently cooled. Therefore, the motor is efficiently cooled by the fluid supplied from the fluid passage. Thus, unlike conventional technology, the motor can be cooled by utilizing a portion of the fluid compressed by the rotation of the impeller without using an intercooler.

[0010] Furthermore, the existing resin component is used to close the opening of the first recess. Therefore, there is no need to provide a separate closing member to close the opening of the first recess, which allows for a reduction in the size of the centrifugal compressor. As a result, the centrifugal compressor can be made smaller.

[0011] In the centrifugal compressor described above, the housing has a first wall that partitions the motor chamber and a second wall connected to the outer surface of the first wall, the first recess is formed on the motor chamber side of the first wall, and a second recess is formed on the first wall side of the second wall, which together with the first wall constitutes a part of the cooling water passage.

[0012] According to this, the second recess, together with the first wall, constitutes part of the cooling water passage, and the first wall is cooled by the cooling water flowing inside the second recess. Therefore, the fluid flowing inside the first recess efficiently dissipates heat to the first wall via multiple cooling fins. As a result, the fluid flowing through the fluid passage is efficiently cooled. Therefore, the motor is efficiently cooled by the fluid supplied from the fluid passage. Thus, as in the prior art, the motor can be cooled by utilizing a portion of the fluid compressed by the rotation of the impeller without using an intercooler.

[0013] In the centrifugal compressor described above, the first wall and the second wall constitute a partition wall that separates the impeller chamber and the motor chamber and has an insertion hole through which the rotating shaft is inserted, and the first recess and the second recess preferably extend in the circumferential direction of the rotating shaft around the insertion hole.

[0014] According to this, since the first and second recesses extend in the circumferential direction of the rotating shaft around the insertion hole, the axial size of the rotating shaft in the centrifugal compressor can be reduced compared to, for example, the case where the first and second recesses extend in the axial direction of the rotating shaft.

[0015] In the centrifugal compressor described above, a bearing is provided to rotatably support the rotating shaft, the first wall has a first hole that forms part of the insertion hole, the second wall has a second hole that forms part of the insertion hole, and the bearing includes a radial bearing that is positioned between the first hole and the rotating shaft and supports the rotating shaft in the radial direction, and at least a portion of the fluid that has passed through the first recess flows through the first hole. As a result, the radial bearing can be cooled by at least a portion of the fluid that has passed through the first recess flowing through the first hole.

[0016] In the centrifugal compressor described above, a thrust collar is provided that protrudes from the outer circumferential surface of the rotating shaft, and a housing chamber is partitioned between the first wall and the second wall, connecting the first hole and the second hole and housing the thrust collar, and the bearing includes a thrust bearing disposed in the housing chamber and supporting the rotating shaft in the thrust direction via the thrust collar, and a portion of the fluid that passes through the first recess flows into the housing chamber. As a result, the thrust bearing can be cooled in addition to the radial bearing by a portion of the fluid that passes through the first recess flowing into the housing chamber.

[0017] In the centrifugal compressor described above, the fluid passage preferably has a discharge passage that discharges the fluid that has passed through the containment chamber to the outside of the housing without passing through the first hole and the motor chamber. This makes it possible to avoid problems such as the radial bearing and motor being heated by the fluid that has cooled the thrust bearing.

[0018] In the centrifugal compressor described above, the fluid passage has a communication hole connecting the first recess and the motor chamber, and at least a portion of the fluid that has passed through the first recess flows into the motor chamber through the communication hole. This allows the motor to be cooled efficiently by allowing at least a portion of the fluid that has passed through the first recess to flow into the motor chamber through the communication hole. [Effects of the Invention]

[0019] According to this invention, miniaturization of the centrifugal compressor can be achieved.

Brief Description of the Drawings

[0020] [Figure 1] It is a cross-sectional view of the centrifugal compressor in the embodiment. [Figure 2] It is a cross-sectional view showing an enlarged part of the centrifugal compressor. [Figure 3] It is a cross-sectional view taken along line 3-3 in FIG. 2. [Figure 4] It is a cross-sectional view taken along line 4-4 in FIG. 2.

Modes for Carrying Out the Invention

[0021] Hereinafter, an embodiment in which the centrifugal compressor is embodied will be described according to FIGS. 1 to 4. Note that the centrifugal compressor in the embodiment described below is mounted on a fuel cell vehicle. The centrifugal compressor compresses air as a fluid supplied to the fuel cell stack.

[0022] <00OO095><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. The housing 11 is, for example, made of aluminum. The housing 11 has a motor housing 12, a first compressor housing 13, a second compressor housing 14, a first plate 15, and a second plate 16.

[0023] The motor housing 12 has an end wall 12a and a peripheral wall 12b. The end wall 12a is plate-shaped. The peripheral wall 12b extends cylindrically from the outer peripheral portion of the end wall 12a. A water jacket 17 is provided in the peripheral wall 12b. The water jacket 17 is annular. Cooling water from a cooling water circuit not shown flows through the water jacket 17. The cooling water flowing through the water jacket 17 cools the motor housing 12.

[0024] The first plate 15 is connected to the opening end of the peripheral wall 12b of the motor housing 12. The first plate 15 closes the opening in the peripheral wall 12b of the motor housing 12. The motor chamber 18 is partitioned by the motor housing 12 and the first plate 15. Therefore, the housing 11 has a motor chamber 18. The housing 11 partitions the motor chamber 18.

[0025] The centrifugal compressor 10 is equipped with a motor 20. The motor 20 is housed in a motor chamber 18. Therefore, the motor chamber 18 houses the motor 20. The motor housing 12 surrounds the motor 20.

[0026] A first hole 15h is formed in the first plate 15. The first hole 15h penetrates the central part of the first plate 15. The first hole 15h is circular in shape. The first end of the first hole 15h communicates with the motor chamber 18. The second end of the first hole 15h opens to the end face of the first plate 15 opposite to the motor housing 12.

[0027] The second plate 16 is connected to the end face of the first plate 15 opposite to the motor housing 12. The second plate 16 is attached to the first plate 15 such that the thickness direction of the second plate 16 coincides with the thickness direction of the first plate 15.

[0028] As shown in Figure 2, the second plate 16 has a chamber-forming recess 21. The chamber-forming recess 21 is formed in the center of the end face of the second plate 16 on the side of the first plate 15. The chamber-forming recess 21 is circular in shape. The axis of the chamber-forming recess 21 coincides with the axis of the first hole 15h. The opening of the chamber-forming recess 21 is closed by the first plate 15. The chamber-forming recess 21 and the first plate 15 then partition the containment chamber 22. Therefore, the containment chamber 22 is partitioned between the first plate 15 and the second plate 16. The containment chamber 22 communicates with the first hole 15h.

[0029] A second hole 16h is formed in the second plate 16. The second hole 16h penetrates the central part of the second plate 16. The second hole 16h is circular in shape. The axis of the second hole 16h coincides with the axis of the chamber forming recess 21 and the axis of the first hole 15h. The second hole 16h communicates with the containment chamber 22. Therefore, the containment chamber 22 communicates with the first hole 15h and the second hole 16h. The first hole 15h and the second hole 16h form the first insertion hole 23. Therefore, the first plate 15 has a first hole 15h that forms part of the first insertion hole 23. The second plate 16 has a second hole 16h that forms part of the first insertion hole 23.

[0030] As shown in Figure 1, a second through-hole 24 is formed in the end wall 12a of the motor housing 12. The second through-hole 24 penetrates the central part of the end wall 12a of the motor housing 12. The second through-hole 24 is circular in shape. The first end of the second through-hole 24 communicates with the motor chamber 18. The second end of the second through-hole 24 opens to the outer surface of the end wall 12a of the motor housing 12.

[0031] The first compressor housing 13 is cylindrical and has a circular first intake port 27 through which air is drawn in. The first compressor housing 13 is connected to the end face of the second plate 16 opposite to the first plate 15, such that the axis of the first intake port 27 coincides with the axis of the second hole 16h. The first intake port 27 opens to the end face of the first compressor housing 13 opposite to the second plate 16. The housing 11 partitions the first intake port 27. Air purified by an air cleaner (not shown) flows through the first intake port 27.

[0032] The centrifugal compressor 10 comprises a first impeller chamber 28, a first discharge chamber 29, and a first diffuser passage 30. The first impeller chamber 28, the first discharge chamber 29, and the first diffuser passage 30 are formed between the first compressor housing 13 and the second plate 16. Therefore, the housing 11 has the first impeller chamber 28. The housing 11 partitions the first impeller chamber 28. The first intake port 27 draws air into the first impeller chamber 28.

[0033] The first plate 15 and the second plate 16 constitute a partition wall separating the first impeller chamber 28 and the motor chamber 18. Therefore, the housing 11 has a partition wall separating the first impeller chamber 28 and the motor chamber 18. The first plate 15 is the first wall that partitions the motor chamber 18. The second plate 16 is the second wall connected to the outer surface of the first plate 15.

[0034] The first impeller chamber 28 is in communication with the first intake port 27. The first discharge chamber 29 extends around the axis of the first intake port 27, surrounding the first impeller chamber 28. The first diffuser flow path 30 connects the first impeller chamber 28 and the first discharge chamber 29. The first impeller chamber 28 is in communication with the second hole 16h.

[0035] The centrifugal compressor 10 has a first discharge passage 31. The first end of the first discharge passage 31 communicates with the first discharge chamber 29. The second end of the first discharge passage 31 opens to the outer surface of the first compressor housing 13.

[0036] The second compressor housing 14 is cylindrical and has a circular second intake port 32 through which air is drawn in. The second compressor housing 14 is connected to the outer surface of the end wall 12a of the motor housing 12, such that the axis of the second intake port 32 coincides with the axis of the second insertion hole 24. The second intake port 32 opens on the end face of the second compressor housing 14 opposite to the motor housing 12. The housing 11 partitions the second intake port 32.

[0037] The centrifugal compressor 10 includes a second impeller chamber 33, a second discharge chamber 34, and a second diffuser passage 35. The second impeller chamber 33, the second discharge chamber 34, and the second diffuser passage 35 are formed between the second compressor housing 14 and the end wall 12a of the motor housing 12. Therefore, the housing 11 has the second impeller chamber 33. The housing 11 partitions the second impeller chamber 33. The second intake port 32 draws air into the second impeller chamber 33.

[0038] The end wall 12a of the motor housing 12 constitutes a partition wall separating the second impeller chamber 33 from the motor chamber 18. Therefore, the housing 11 has a partition wall separating the second impeller chamber 33 from the motor chamber 18. The second impeller chamber 33 is in communication with the second intake port 32. The second discharge chamber 34 extends around the axis of the second intake port 32, surrounding the second impeller chamber 33. The second diffuser flow path 35 connects the second impeller chamber 33 and the second discharge chamber 34. The second impeller chamber 33 is in communication with the second insertion hole 24.

[0039] The centrifugal compressor 10 has a second discharge passage 36. The first end of the second discharge passage 36 communicates with the second discharge chamber 34. The second end of the second discharge passage 36 opens to the outer surface of the second compressor housing 14. A supply pipe 37 is connected to the second discharge passage 36. The supply pipe 37 is connected to the fuel cell stack 38. The first end of the supply pipe 37 is connected to the second discharge passage 36. The second end of the supply pipe 37 is connected to the fuel cell stack 38. The second discharge chamber 34 is connected to the fuel cell stack 38 via the second discharge passage 36 and the supply pipe 37.

[0040] The centrifugal compressor 10 is equipped with a connecting pipe 39. The first end of the connecting pipe 39 is in communication with the first discharge passage 31. The second end of the connecting pipe 39 is in communication with the second intake port 32. Air discharged from the first discharge chamber 29 to the first discharge passage 31 flows through the connecting pipe 39. The air that has passed through the connecting pipe 39 is then drawn into the second impeller chamber 33 via the second intake port 32.

[0041] The centrifugal compressor 10 comprises a rotating body 40. The rotating body 40 includes a rotating shaft 41, a first impeller 42, a second impeller 43, and a thrust collar 44. Thus, the centrifugal compressor 10 comprises a rotating shaft 41, impellers which are a first impeller 42 and a second impeller 43, and a thrust collar 44. The rotating shaft 41 is housed in a housing 11.

[0042] The first impeller 42 is housed in the first impeller chamber 28. Therefore, the first impeller chamber 28 is an impeller chamber that houses the first impeller 42. The second impeller 43 is housed in the second impeller chamber 33. Therefore, the second impeller chamber 33 is an impeller chamber that houses the second impeller 43.

[0043] The rotating shaft 41 extends along the axis of the motor housing 12 and crosses the motor chamber 18. The axial direction of the rotating shaft 41 coincides with the axial direction of the motor housing 12. The first end of the rotating shaft 41 protrudes from the motor chamber 18 through the first hole 15h, the housing chamber 22, and the second hole 16h into the first impeller chamber 28. Therefore, the first insertion hole 23 is an insertion hole through which the rotating shaft 41 is inserted. In this way, the first plate 15 and the second plate 16 constitute a partition wall that separates the first impeller chamber 28 and the motor chamber 18 and has the first insertion hole 23 through which the rotating shaft 41 is inserted.

[0044] The second end of the rotating shaft 41 protrudes from the motor chamber 18 through the second insertion hole 24 into the second impeller chamber 33. Therefore, the second insertion hole 24 is an insertion hole through which the rotating shaft 41 is inserted. In this way, the end wall 12a of the motor housing 12 constitutes a partition wall that separates the second impeller chamber 33 from the motor chamber 18 and has a second insertion hole 24 through which the rotating shaft 41 is inserted.

[0045] A first impeller 42 is connected to the first end of the rotating shaft 41. The first impeller 42 rotates integrally with the rotating shaft 41 to compress the air drawn into the first impeller chamber 28. A second impeller 43 is connected to the second end of the rotating shaft 41. The second impeller 43 rotates integrally with the rotating shaft 41 to compress the air drawn into the second impeller chamber 33. The second impeller 43 rotates to compress the air that has been compressed by the rotation of the first impeller 42.

[0046] The thrust collar 44 protrudes annularly from the outer circumferential surface of the rotating shaft 41. The thrust collar 44 is disc-shaped. The thrust collar 44 is fixed to the outer circumferential surface of the rotating shaft 41, protruding annularly radially outward from the outer circumferential surface of the rotating shaft 41. The thrust collar 44 is separate from the rotating shaft 41. The thrust collar 44 is located in the housing chamber 22. Therefore, the housing chamber 22 houses the thrust collar 44. The thrust collar 44 rotates integrally with the rotating shaft 41.

[0047] The centrifugal compressor 10 is equipped with a first sealing member 45. The first sealing member 45 is provided between the second hole 16h and the rotating shaft 41. The first sealing member 45 suppresses air leakage from the first impeller chamber 28 to the motor chamber 18 through the first insertion hole 23. The first sealing member 45 is, for example, a sealing ring.

[0048] The centrifugal compressor 10 is equipped with a second sealing member 46. The second sealing member 46 is provided between the second insertion hole 24 and the rotating shaft 41. The second sealing member 46 suppresses air leakage from the second impeller chamber 33 to the motor chamber 18 through the second insertion hole 24. The second sealing member 46 is, for example, a sealing ring.

[0049] The motor 20 has a cylindrical rotor 47 and a cylindrical stator 48. The rotor 47 is fixed to the rotating shaft 41. The stator 48 is fixed to the housing 11. The rotor 47 is positioned radially inward of the stator 48. The rotor 47 rotates integrally with the rotating shaft 41. The rotor 47 has a cylindrical rotor core 49 fixed to the rotating shaft 41 and a plurality of permanent magnets (not shown) provided on the rotor core 49. The stator 48 surrounds the rotor 47. The stator 48 has a cylindrical stator core 50 and a coil 51. The stator core 50 is fixed to the inner circumferential surface of the motor housing 12. The coil 51 is wound around the stator core 50.

[0050] The rotating shaft 41 rotates integrally with the rotor 47 when current flows from a battery (not shown) to a coil 51. Therefore, the motor 20 rotates the rotating shaft 41. The motor 20 is positioned between the first impeller 42 and the second impeller 43 in the axial direction of the rotating shaft 41.

[0051] The stator 48 has coil ends 52. The coil ends 52 are part of the coil 51 and protrude from both ends of the stator core 50. In the following description, the coil end 52 located on the first plate 15 side of the stator core 50 will be referred to as the "first coil end 52a". The coil end 52 located on the end wall 12a side of the motor housing 12 of the stator core 50 will be referred to as the "second coil end 52b".

[0052] The stator 48 has a resin 53. The resin 53 covers the stator core 50 and the coil end 52. The resin 53 molds the coil end 52. The resin 53 has a first resin part 53a, a second resin part 53b, and a third resin part 53c. The first resin part 53a is cylindrical and covers the first coil end 52a. The second resin part 53b is cylindrical and covers the second coil end 52b. The third resin part 53c is cylindrical and covers the inner circumferential surface of the stator core 50. The third resin part 53c connects the first resin part 53a and the second resin part 53b.

[0053] The first resin part 53a is thermally bonded to the inner surface of the peripheral wall 12b of the motor housing 12 and to the surface of the first plate 15 facing the motor chamber 18. The second resin part 53b is thermally bonded to the inner surface of the peripheral wall 12b of the motor housing 12 and to the inner surface of the end wall 12a of the motor housing 12. The heat generated from the coil 51 is dissipated from the first coil end 52a through the first resin part 53a to the peripheral wall 12b of the motor housing 12 and the first plate 15. The heat generated from the coil 51 is also dissipated from the second coil end 52b through the second resin part 53b to the peripheral wall 12b and the end wall 12a of the motor housing 12. Therefore, the heat generated from the coil 51 is dissipated from the coil end 52 through the resin 53 to the housing 11.

[0054] The centrifugal compressor 10 is equipped with a first radial bearing 54 as a radial bearing. The first radial bearing 54 is cylindrical. The first radial bearing 54 is an air bearing. The first radial bearing 54 is located between the first hole 15h and the rotating shaft 41. The first radial bearing 54 is a bearing that rotatably supports the portion of the rotating shaft 41 that is located closer to the first end of the rotating shaft 41 than the motor 20.

[0055] The centrifugal compressor 10 is equipped with a second radial bearing 55, which is a radial bearing. The second radial bearing 55 is cylindrical. The second radial bearing 55 is an air bearing. The second radial bearing 55 is located between the second insertion hole 24 and the rotating shaft 41. The second radial bearing 55 is a bearing that rotatably supports the portion of the rotating shaft 41 that is located closer to the second end of the rotating shaft 41 than the motor 20. The second radial bearing 55 is located closer to the motor chamber 18 than the second seal member 46.

[0056] The first radial bearing 54 and the second radial bearing 55 support the motor 20 so that the rotating shaft 41 can rotate radially at positions on both sides of the rotating shaft 41 in the axial direction of the motor 20. The "radial direction" refers to the direction perpendicular to the axial direction of the rotating shaft 41.

[0057] The centrifugal compressor 10 is equipped with a thrust bearing 56. The thrust bearing 56 is located within a housing chamber 22. Therefore, the housing chamber 22 houses the thrust bearing 56. The thrust bearing 56 is a bearing that supports the rotating shaft 41 so that it can rotate in the thrust direction via a thrust collar 44. The "thrust direction" is the direction parallel to the rotation axis direction of the rotating shaft 41. Thus, the centrifugal compressor 10 is equipped with a bearing that supports the rotating shaft 41 so that it can rotate. The bearing includes a first radial bearing 54 and a second radial bearing 55, which are radial bearings, and a thrust bearing 56.

[0058] Air drawn into the first impeller chamber 28 via the first intake port 27 is accelerated by the rotation of the first impeller 42 and sent to the first diffuser flow path 30, where it is pressurized as it passes through the first diffuser flow path 30. The air that has passed through the first diffuser flow path 30 is then discharged into the first discharge chamber 29. The air discharged into the first discharge chamber 29 is then discharged into the first discharge passage 31. The air discharged into the first discharge passage 31 is drawn into the second impeller chamber 33 via the connecting pipe 39 and the second intake port 32. The air drawn into the second impeller chamber 33 is accelerated by the rotation of the second impeller 43 and sent to the second diffuser flow path 35, where it is pressurized as it passes through the second diffuser flow path 35. The air that has passed through the second diffuser flow path 35 is then discharged into the second discharge chamber 34. The air discharged into the second discharge chamber 34 is then discharged into the second discharge passage 36. The air discharged into the second discharge passage 36 is supplied to the fuel cell stack 38 via the supply pipe 37. Thus, the centrifugal compressor 10 supplies air to the fuel cell stack 38. The oxygen contained in the air supplied to the fuel cell stack 38 contributes to the power generation of the fuel cell stack 38.

[0059] <Fluid passage 60> As shown in Figures 2 and 3, the centrifugal compressor 10 is provided with a first recess 61. The first recess 61 is formed on the motor chamber 18 side surface of the first plate 15. Therefore, the first recess 61 is formed on the motor chamber 18 side surface of the housing 11. The first recess 61 extends in the circumferential direction of the rotating shaft 41 around the first insertion hole 23. The first recess 61 is annular.

[0060] Multiple cooling fins 62 protrude from the bottom surface of the first recess 61. The multiple cooling fins 62 are annular in shape. The multiple cooling fins 62 are arranged in concentric circles centered on the axis of the first recess 61. The height of each cooling fin 62 protruding from the bottom surface of the first recess 61 is lower than the surface of the first plate 15 on the motor chamber 18 side.

[0061] As shown in Figure 2, the first resin part 53a closes the opening of the first recess 61. Therefore, the resin 53 closes the opening of the first recess 61. The annular passage 63 is partitioned by the first recess 61 and the resin 53. A heat dissipation sheet 64 is interposed between the first resin part 53a and the surface of the first plate 15 facing the motor chamber 18. The heat dissipation sheet 64 is made of rubber, for example. The heat dissipation sheet 64 absorbs the dimensional tolerance of the first resin part 53a by elastically deforming between the first resin part 53a and the surface of the first plate 15 facing the motor chamber 18.

[0062] A fluid introduction passage 65 is formed in the first plate 15. The first end of the fluid introduction passage 65 opens to the outer circumferential surface of the first plate 15. The second end of the fluid introduction passage 65 communicates with the inside of the first recess 61. Therefore, the second end of the fluid introduction passage 65 communicates with the annular passage 63.

[0063] A first supply passage 66 is formed in the first plate 15. The first end of the first supply passage 66 communicates with the inside of the first recess 61. Therefore, the first end of the first supply passage 66 communicates with the annular passage 63. The second end of the first supply passage 66 communicates with the first hole 15h. Therefore, the first supply passage 66 communicates the first recess 61 and the first insertion hole 23.

[0064] A second supply passage 67 is formed in the first plate 15. The first end of the second supply passage 67 communicates with the first supply passage 66. Therefore, the first end of the second supply passage 67 communicates with the first recess 61 via the first supply passage 66. The second end of the second supply passage 67 communicates with the storage chamber 22.

[0065] A communication hole 68 is formed in the first plate 15. The first end of the communication hole 68 communicates with the first supply passage 66. Therefore, the communication hole 68 communicates with the first recess 61 via the first supply passage 66. The second end of the communication hole 68 communicates with the motor chamber 18. Therefore, the communication hole 68 connects the first recess 61 and the motor chamber 18.

[0066] A discharge passage 69 is formed in the second plate 16. The first end of the discharge passage 69 communicates with the containment chamber 22. The second end of the discharge passage 69 opens onto the outer surface of the second plate 16. The discharge passage 69 connects the containment chamber 22 to the outside of the housing 11.

[0067] As shown in Figure 1, a fluid discharge passage 70 is formed in the end wall 12a of the motor housing 12. The first end of the fluid discharge passage 70 communicates with the portion of the second insertion hole 24 between the second radial bearing 55 and the second sealing member 46. The second end of the fluid discharge passage 70 opens to the outer circumferential surface of the end wall 12a. The fluid discharge passage 70 communicates the second insertion hole 24 with the outside of the housing 11.

[0068] A branch pipe 57 is connected to the first end of the fluid introduction passage 65. The branch pipe 57 branches off from the middle of the supply pipe 37. The first end of the branch pipe 57 is connected to the supply pipe 37. The second end of the branch pipe 57 is connected to the first end of the fluid introduction passage 65.

[0069] A portion of the air flowing through the supply pipe 37 flows into the branch pipe 57. The air that flows into the branch pipe 57 is introduced into the annular passage 63 via the fluid introduction passage 65. The air introduced into the annular passage 63 passes through the annular passage 63 and flows into the first supply pipe 66.

[0070] A portion of the air that flows into the first supply passage 66 flows into the first hole 15h. The air that flows into the first hole 15h flows through the first hole 15h to the motor room 18. Therefore, a portion of the air that passes through the first recess 61 flows through the first hole 15h.

[0071] Furthermore, a portion of the air that flows into the first supply passage 66 flows into the second supply passage 67. The air that flows into the second supply passage 67 is introduced into the housing chamber 22. Therefore, a portion of the air that passes through the first recess 61 also flows into the housing chamber 22. The air introduced into the housing chamber 22 passes through the housing chamber 22 and flows into the discharge passage 69, and is also discharged to the outside of the housing 11 via the discharge passage 69. Therefore, the discharge passage 69 discharges the air that has passed through the housing chamber 22 to the outside of the housing 11 without passing through the first hole 15h and the motor chamber 18.

[0072] A portion of the air that flows into the first supply passage 66 flows into the motor room 18 through the communication hole 68. Therefore, a portion of the air that passes through the first recess 61 flows into the motor room 18 through the communication hole 68.

[0073] The air that flows into the motor chamber 18 flows from the motor chamber 18 into the second insertion hole 24. The air that flows into the second insertion hole 24 is then discharged from the second insertion hole 24 to the outside of the housing 11 via the fluid discharge passage 70.

[0074] Thus, the housing 11 has a fluid passage 60 through which a portion of the air compressed by the rotation of the second impeller 43 flows. The fluid introduction passage 65, the annular passage 63, the first supply passage 66, the second supply passage 67, the housing chamber 22, the discharge passage 69, the communication hole 68, the first hole 15h, the motor chamber 18, the second insertion hole 24, and the fluid discharge passage 70 constitute the fluid passage 60. Therefore, the first recess 61 constitutes a part of the fluid passage 60. The resin 53 closes the opening of the first recess 61, thereby partitioning a part of the fluid passage 60 together with the first recess 61. The fluid passage 60 has a discharge passage 69. The fluid passage 60 has a communication hole 68.

[0075] <Cooling water passage 71> As shown in Figures 2 and 4, the centrifugal compressor 10 is provided with a second recess 72. The second recess 72 is formed on the surface of the second plate 16 that faces the first plate 15. Therefore, the second recess 72 is formed on the surface of the second plate 16 that faces the first plate 15. The second recess 72 extends in the circumferential direction of the rotating shaft 41 around the first insertion hole 23.

[0076] As shown in Figure 4, the second recess 72 is C-shaped when viewed from the front. Therefore, the second recess 72 is non-annular. The second recess 72 extends approximately one full turn in the circumferential direction of the rotation axis 41 around the first insertion hole 23. The first circumferential end and the second circumferential end of the second recess 72 are adjacent to each other, separated by a straight line L1 that radially crosses the axis of the first insertion hole 23.

[0077] As shown in Figure 2, the first plate 15 closes the opening of the second recess 72. The non-annular passage 73 is then partitioned by the second recess 72 and the first plate 15. As shown in Figure 4, the centrifugal compressor 10 includes a cooling water introduction passage 74 and a cooling water return passage 75. The cooling water introduction passage 74 has a first passage hole 74a and a second passage hole 74b. The first passage hole 74a penetrates the circumferential wall 12b of the motor housing 12, the first plate 15, and the second plate 16 in the axial direction of the rotating shaft 41. The second passage hole 74b is formed in the second plate 16.

[0078] The first end of the first passage hole 74a communicates with the water jacket 17. The second end of the first passage hole 74a communicates with the second passage hole 74b. The first end of the second passage hole 74b opens onto the outer circumferential surface of the second plate 16. The second end of the second passage hole 74b communicates with the first end of the second recess 72. Therefore, the cooling water introduction passage 74 communicates the water jacket 17 with the first end of the non-annular passage 73. The first end of the second passage hole 74b is sealed by the first sealing member 74c.

[0079] The cooling water recirculation passage 75 has a third passage hole 75a and a fourth passage hole 75b. The third passage hole 75a is formed in the second plate 16. The fourth passage hole 75b penetrates the circumferential wall 12b of the motor housing 12, the first plate 15, and the interior of the second plate 16 in the axial direction of the rotating shaft 41. The first end of the third passage hole 75a communicates with the second end of the second recess 72. The second end of the third passage hole 75a opens onto the outer circumferential surface of the second plate 16. The first end of the fourth passage hole 75b communicates with the third passage hole 75a. The second end of the fourth passage hole 75b communicates with the water jacket 17. Therefore, the cooling water recirculation passage 75 communicates the second end of the non-annular passage 73 with the water jacket 17. The second end of the third passage hole 75a is sealed by the second sealing member 75c.

[0080] The cooling water flowing through the water jacket 17 flows into the first end of the non-annular passage 73 via the cooling water introduction passage 74. The cooling water that has flowed into the non-annular passage 73 flows from the first end to the second end of the non-annular passage 73. Then, the cooling water flowing through the non-annular passage 73 is returned to the water jacket 17 from the second end of the non-annular passage 73 via the cooling water return passage 75.

[0081] Thus, the housing 11 has a cooling water passage 71 through which cooling water flows to cool the housing 11. The water jacket 17, the cooling water introduction passage 74, the non-annular passage 73, and the cooling water return passage 75 constitute the cooling water passage 71. Therefore, the second recess 72, together with the first plate 15, constitutes part of the cooling water passage 71.

[0082] As shown in Figure 2, multiple cooling water fins 76 protrude from the surface of the first plate 15 facing the second plate 16. The multiple cooling water fins 76 are recessed into the second recess 72. The tip of each cooling water fin 76 is spaced apart from the bottom surface of the second recess 72. As shown in Figure 4, the multiple cooling water fins 76 are C-shaped when viewed from the front. The multiple cooling water fins 76 extend along the second recess 72.

[0083] [Effect of the Embodiment] Next, the operation of this embodiment will be described. The thrust bearing 56 is cooled by air passing through the housing chamber 22. The first radial bearing 54 is cooled by air passing through the first hole 15h of the first insertion hole 23. The motor 20 is cooled by air passing through the motor chamber 18. The second radial bearing 55 is cooled by air passing through the second insertion hole 24. In this way, the centrifugal compressor 10 cools the thrust bearing 56, the first radial bearing 54, the second radial bearing 55, and the motor 20 by introducing a portion of the air compressed by the second impeller 43 into the housing 11.

[0084] Since the housing 11 is cooled by the cooling water flowing through the cooling water passage 71, the air flowing inside the first recess 61 efficiently dissipates heat to the housing 11 via the multiple cooling fins 62. Specifically, the second recess 72, together with the first plate 15, constitutes part of the cooling water passage 71. The heat from the first plate 15 is dissipated to the cooling water flowing inside the second recess 72 via the multiple cooling fins 76. Therefore, the first plate 15 is cooled by the cooling water flowing inside the second recess 72. Consequently, the air flowing inside the first recess 61 efficiently dissipates heat to the first plate 15 via the multiple cooling fins 62. As a result, the air flowing through the fluid passage 60 is efficiently cooled. Therefore, the motor 20, the first radial bearing 54, the second radial bearing 55, and the thrust bearing 56 are efficiently cooled by the air supplied from the fluid passage 60.

[0085] Thus, cooling water flows through the cooling water passage 71 to cool the housing 11 in order to cool the motor 20, the first radial bearing 54, the second radial bearing 55, and the thrust bearing 56. In addition, a portion of the air compressed by the rotation of the second impeller 43 flows through the fluid passage 60 to cool the motor 20, the first radial bearing 54, the second radial bearing 55, and the thrust bearing 56.

[0086] [Effects of the Embodiment] The above embodiment can be achieved to obtain the following effects. (1) The housing 11 is cooled by the cooling water flowing through the cooling water passage 71, so that the air flowing inside the first recess 61 efficiently dissipates heat to the housing 11 via the multiple cooling fins 62. As a result, the air flowing through the fluid passage 60 is efficiently cooled. Therefore, the motor 20, the first radial bearing 54, the second radial bearing 55, and the thrust bearing 56 are efficiently cooled by the air supplied from the fluid passage 60. Thus, as in the prior art, the motor 20, the first radial bearing 54, the second radial bearing 55, and the thrust bearing 56 can be cooled by utilizing a portion of the air compressed by the rotation of the second impeller 43 without using an intercooler.

[0087] Furthermore, the existing resin 53 is used to close the opening of the first recess 61. Therefore, there is no need to provide a separate closing member to close the opening of the first recess 61, and thus the centrifugal compressor 10 can be made smaller. As a result, the centrifugal compressor 10 can be made smaller.

[0088] (2) Since the second recess 72, together with the first plate 15, constitutes part of the cooling water passage 71, the first plate 15 is cooled by the cooling water flowing inside the second recess 72. Therefore, the air flowing inside the first recess 61 efficiently dissipates heat to the first plate 15 via the multiple cooling fins 62. As a result, the air flowing through the fluid passage 60 is efficiently cooled. Therefore, the motor 20, the first radial bearing 54, the second radial bearing 55, and the thrust bearing 56 are efficiently cooled by the air supplied from the fluid passage 60. Thus, as in the prior art, the motor 20, the first radial bearing 54, the second radial bearing 55, and the thrust bearing 56 can be cooled by utilizing a portion of the air compressed by the rotation of the second impeller 43 without using an intercooler.

[0089] (3) The first recess 61 and the second recess 72 extend in the circumferential direction of the rotating shaft 41 around the first insertion hole 23. Therefore, compared to the case where the first recess 61 and the second recess 72 extend in the axial direction of the rotating shaft 41, for example, the axial size of the rotating shaft 41 in the centrifugal compressor 10 can be reduced.

[0090] (4) The air that has passed through the first recess 61 flows through the first hole 15h, thereby cooling the first radial bearing 54. (5) A portion of the air that has passed through the first recess 61 also flows into the housing chamber 22, thereby cooling the thrust bearing 56 in addition to the first radial bearing 54.

[0091] (6) The fluid passage 60 has a discharge passage 69 that discharges the air that has passed through the containment chamber 22 to the outside of the housing 11 without passing through the first hole 15h and the motor chamber 18. This makes it possible to avoid problems such as the first radial bearing 54 and the motor 20 being heated by the air that has cooled the thrust bearing 56.

[0092] (7) The air that has passed through the first recess 61 flows into the motor chamber 18 through the communication hole 68, thereby efficiently cooling the motor 20. [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0093] ○ In this embodiment, the second recess 72 does not necessarily have to be formed in the second plate 16. Furthermore, for example, a part of the cooling water passage 71 may be formed inside the first plate 15. The point is that the air flowing inside the first recess 61 is dissipated to the housing 11 via the multiple cooling fins 62.

[0094] ○ In this embodiment, the first recess 61 and the second recess 72 may extend in the axial direction of the rotating shaft 41. For example, the first recess 61 may be formed on the inner circumferential surface of the peripheral wall 12b of the motor housing 12, and the second recess may be formed in a cylindrical housing member surrounding the peripheral wall 12b of the motor housing 12. In this case, the peripheral wall 12b of the motor housing 12 is the first wall, and the cylindrical housing member surrounding the peripheral wall 12b of the motor housing 12 is the second wall.

[0095] ○ In this embodiment, the first recess 61 and the second recess 72 may extend in the circumferential direction of the rotation axis 41 around the second insertion hole 24. ○ In this embodiment, the fluid passage 60 may not have a second supply passage 67 and a communication hole 68. In this case, all the air that passes through the first recess 61 flows through the first hole 15h. In short, it is sufficient that at least a portion of the air that passes through the first recess 61 flows through the first hole 15h.

[0096] ○ In this embodiment, the fluid passage 60 may not have a second supply passage 67. In short, the centrifugal compressor 10 may be configured so that a portion of the air that has passed through the first recess 61 does not flow into the containment chamber 22.

[0097] ○ In this embodiment, the fluid passage 60 may be configured without a discharge passage 69. In this case, the air that has passed through the containment chamber 22 passes through the first hole 15h and the motor chamber 18.

[0098] ○ In this embodiment, the fluid passage 60 may be configured without having a communication hole 68. ○ In this embodiment, the fluid passage 60 may not have a second supply passage 67. Furthermore, the first supply passage 66 may not be in communication with the first hole 15h. Furthermore, the fluid discharge passage 70 may be in communication with the motor chamber 18 and the outside of the housing 11. The fluid discharge passage 70 discharges the air inside the motor chamber 18 to the outside of the housing 11. In this case, all the air that has passed through the first recess 61 flows into the motor chamber 18 through the communication hole 68 and is also discharged to the outside of the housing 11 through the fluid discharge passage 70. In short, it is sufficient that at least a portion of the air that has passed through the first recess 61 flows into the motor chamber 18 through the communication hole 68. In this case, the air flowing through the fluid passage 60 cools only the motor 20. In short, it is sufficient that the fluid passage 60 is configured to carry a portion of the air compressed by the rotation of the second impeller 43 in order to cool the motor 20. Furthermore, the cooling water passage 71 should be configured such that cooling water flows through it to cool the housing 11 in order to cool the motor 20.

[0099] ○ In this embodiment, each cooling fin 62 does not have to be annular; for example, it may be cylindrical. In short, the shape of each cooling fin 62 is not particularly limited. ○ In the embodiment, each cooling water fin 76 was C-shaped when viewed from the front, but it is not limited to this, and may be cylindrical, for example. In short, the shape of each cooling water fin 76 is not particularly limited.

[0100] ○ In this embodiment, the cooling water fins 76 do not necessarily have to protrude from the surface of the first plate 15 that faces the second plate 16. ○ In this embodiment, the heat dissipation sheet 64 does not need to be interposed between the first resin part 53a and the first plate 15.

[0101] ○ In this embodiment, the centrifugal compressor 10 may be configured without a second impeller 43. In this case, a portion of the air compressed by the rotation of the first impeller 42 flows through the fluid passage 60.

[0102] ○ In this embodiment, the centrifugal compressor 10 may be configured to include a turbine wheel instead of the second impeller 43. In this case, a portion of the air compressed by the rotation of the first impeller 42 flows through the fluid passage 60.

[0103] ○ In this embodiment, the centrifugal compressor 10 does not have to be installed in the fuel cell vehicle. In short, the centrifugal compressor 10 is not limited to being installed in a vehicle. ○ In this embodiment, the centrifugal compressor 10 is not limited to one used to compress air supplied to the fuel cell stack 38. In short, the centrifugal compressor 10 can be any compressor that compresses a fluid. [Explanation of Symbols]

[0104] 10...Centrifugal compressor, 11...Housing, 12a...End wall (partition wall), 15...First wall, which is the first plate (partition wall), 15h...First hole, 16...Second wall, which is the second plate (partition wall), 16h...Second hole, 18...Motor chamber, 20...Motor, 22...Housing chamber, 23...First insertion hole (insertion hole), 26...Second insertion hole (insertion hole), 28...First impeller chamber (impeller chamber), 33...Second impeller chamber (impeller chamber), 41...Rotating shaft, 42...First impeller (impeller 43... Second impeller (impeller), 44... Thrust collar, 48... Stator, 50... Stator core, 51... Coil, 52... Coil end, 53... Resin, 54... First radial bearing (bearing) as a radial bearing, 55... Second radial bearing (bearing) as a radial bearing, 56... Thrust bearing (bearing), 60... Fluid passage, 61... First recess, 62... Cooling fin, 68... Communication hole, 69... Discharge passage, 71... Cooling water passage, 72... Second recess.

Claims

1. The axis of rotation and An impeller that rotates integrally with the rotating shaft to compress the fluid, A motor having a cylindrical stator and rotating the aforementioned rotating shaft, The system comprises an impeller chamber for housing the impeller and a housing that separates the motor chamber for housing the motor, The aforementioned housing is A cooling water passage through which cooling water flows to cool the housing in order to cool the motor, The motor has a fluid passage through which a portion of the fluid compressed by the rotation of the impeller flows in order to cool the motor, The stator is, Stator core and A coil end which is part of the coil wound around the stator core and protrudes from the end face of the stator core, The coil end is molded from a resin, A centrifugal compressor in which heat generated from the coil is dissipated from the coil end through the resin to the housing, A first recess is formed on the motor chamber side of the housing, which constitutes part of the fluid passage. Multiple cooling fins protrude from the bottom surface of the first recess. The resin, by closing the opening of the first recess, partitions a part of the fluid passage together with the first recess. The fluid flowing inside the first recess is dissipated to the housing via the plurality of cooling fins. The aforementioned housing is The first wall partitioning the motor room, It has a second wall connected to the outer surface of the first wall, The first recess is formed on the surface of the first wall facing the motor chamber, A centrifugal compressor characterized in that a second recess is formed on the surface of the second wall facing the first wall, which together with the first wall constitutes a part of the cooling water passage.

2. The first wall and the second wall constitute a partition wall that separates the impeller chamber and the motor chamber and has an insertion hole through which the rotating shaft is inserted. The centrifugal compressor according to claim 1, characterized in that the first recess and the second recess extend in the circumferential direction of the rotating shaft around the insertion hole.

3. The rotating shaft is provided with a bearing that rotatably supports it, The first wall has a first hole formed in it that forms part of the insertion hole. The second wall has a second hole formed in it that forms part of the insertion hole. The bearing includes a radial bearing that is positioned between the first hole and the rotating shaft and supports the rotating shaft in the radial direction. The centrifugal compressor according to claim 2, characterized in that at least a portion of the fluid that has passed through the first recess flows through the first hole.

4. The rotating shaft is provided with a thrust collar that protrudes from the outer circumferential surface, Between the first wall and the second wall, there is a compartment that connects the first hole and the second hole and houses the thrust collar. The bearing includes a thrust bearing that is disposed within the housing chamber and supports the rotating shaft in the thrust direction via the thrust collar. The centrifugal compressor according to claim 3, characterized in that a portion of the fluid that has passed through the first recess also flows into the containment chamber.

5. The centrifugal compressor according to claim 4, characterized in that the fluid passage has a discharge passage for discharging the fluid that has passed through the containment chamber to the outside of the housing without passing through the first hole and the motor chamber.

6. The axis of rotation and An impeller that rotates integrally with the rotating shaft to compress the fluid, A motor having a cylindrical stator and rotating the aforementioned rotating shaft, The system comprises an impeller chamber for housing the impeller and a housing that separates the motor chamber for housing the motor, The aforementioned housing is A cooling water passage through which cooling water flows to cool the housing in order to cool the motor, The motor has a fluid passage through which a portion of the fluid compressed by the rotation of the impeller flows in order to cool the motor, The stator is, Stator core and A coil end which is part of the coil wound around the stator core and protrudes from the end face of the stator core, The coil end is molded from a resin, A centrifugal compressor in which heat generated from the coil is dissipated from the coil end through the resin to the housing, A first recess is formed on the motor chamber side of the housing, which constitutes part of the fluid passage. Multiple cooling fins protrude from the bottom surface of the first recess. The resin, by closing the opening of the first recess, partitions a part of the fluid passage together with the first recess. The fluid flowing inside the first recess is dissipated to the housing via the plurality of cooling fins. The fluid passage has a communication hole that connects the first recess and the motor chamber. A centrifugal compressor characterized in that at least a portion of the fluid that has passed through the first recess flows into the motor chamber through the communication hole.

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