JP7708003B2 - electric fluid machine - Google Patents

Description

The present invention relates to an electric fluid machine.

An electric fluid machine that constitutes part of a fuel cell system and supplies air to a fuel cell stack is disclosed in, for example, Patent Document 1. Such an electric fluid machine includes a rotating shaft, a motor, a compression section, a regeneration section, and a housing. The motor rotates the rotating shaft. The compression section compresses air as the rotating shaft rotates. The compression section supplies the compressed air to the fuel cell stack. The regeneration section rotates by exhaust gas discharged from the fuel cell stack to assist in driving the motor. The housing has a motor chamber and a regeneration chamber. The motor chamber houses the motor. The regeneration chamber houses the regeneration section. The rotating shaft is supported by a radial bearing and a thrust bearing.

International Publication No. 2019/159744

In such electric fluid machines, in order to cool the radial bearing, thrust bearing, and motor, it is considered to introduce into the housing a portion of the air compressed by the compression unit and supplied to the fuel cell stack. However, because the portion of the air supplied to the fuel cell stack is compressed by the compression unit and is at a high temperature, it is necessary to cool the portion of the air supplied to the fuel cell stack, for example, using an intercooler, before introducing it into the housing. Therefore, the intercooler is a factor in increasing the size of the entire fuel cell system.

In addition, in such fuel cell systems, the exhaust gas discharged from the fuel cell stack contains water that is generated when the fuel cell stack generates electricity. Therefore, the exhaust gas introduced from the fuel cell stack into the regeneration chamber contains water. At this time, if the pressure inside the motor chamber falls below the pressure inside the regeneration chamber, there is a risk that the water present in the regeneration chamber will enter the motor chamber. If water enters the motor chamber, it may have a negative effect on the motor.

The electric fluid machine that solves the above problem is an electric fluid machine that constitutes a part of a fuel cell system and supplies air to a fuel cell stack, and includes a rotating shaft, a motor that rotates the rotating shaft, a first compression section that compresses air as the rotating shaft rotates, a second compression section that compresses the air after it has been compressed by the first compression section as the rotating shaft rotates and supplies the air to the fuel cell stack, a regeneration section that rotates with exhaust gas discharged from the fuel cell stack to assist in driving the motor, and a housing having a first compression chamber that accommodates the first compression section, a second compression chamber that accommodates the second compression section, a motor chamber that accommodates the motor, and a regeneration chamber that accommodates the regeneration section, and the first compression section is provided at one end of the rotating shaft that is closer to the motor, and a second compression chamber that accommodates the regeneration section is provided at the other end of the rotating shaft that is closer to the motor. , the regeneration unit is provided, and the motor and the second compression unit are provided between the first compression unit and the regeneration unit on the rotating shaft, and a first radial bearing that supports the regeneration unit and the motor on the rotating shaft in the radial direction, a second radial bearing that supports the first compression unit and the motor on the rotating shaft in the radial direction, and a thrust bearing that is disposed between the first compression unit and the regeneration unit on the rotating shaft and supports the rotating shaft in the thrust direction, an introduction flow path that introduces at least a portion of the air compressed by the first compression unit into the housing between the first compression chamber and the regeneration chamber, and an intake flow path through which the air introduced into the housing from the introduction flow path is sucked into the second compression unit after cooling the first radial bearing, the second radial bearing, the thrust bearing, and the motor.

According to this, the temperature of the air compressed by the first compression section is lower than the temperature of the air compressed by the second compression section. At least a portion of the air compressed by the first compression section is introduced into the housing between the first compression chamber and the regeneration chamber through the introduction flow path. Therefore, for example, compared to the case where a portion of the air compressed by the second compression section is introduced into the housing, air with a lower temperature can be introduced into the housing. Then, the air introduced into the housing from the introduction flow path cools the first radial bearing, the second radial bearing, the thrust bearing, and the motor, and is then sucked into the second compression section through the intake flow path. The air sucked into the second compression section through the intake flow path is compressed by the second compression section. The air compressed by the second compression section is supplied to the fuel cell stack. Therefore, unlike the conventional technology, it is not necessary to cool a portion of the air supplied to the fuel cell stack using an intercooler before introducing it into the housing, so the intercooler can be eliminated. As a result, the increase in size of the entire fuel cell system is suppressed.

The air introduced between the first compression chamber and the regeneration chamber in the housing is compressed and pressurized by the first compression section. Therefore, at least a portion of the air compressed by the first compression section is introduced between the first compression chamber and the regeneration chamber in the housing through the introduction passage, thereby increasing the pressure between the first compression chamber and the regeneration chamber in the housing. Here, the motor chamber is located between the first compression chamber and the regeneration chamber in the housing. Therefore, the pressure in the motor chamber is prevented from falling below the pressure in the regeneration chamber. Therefore, water present in the regeneration chamber is prevented from entering the motor chamber. As a result, it is possible to prevent the size of the entire fuel cell system from increasing, while preventing water present in the regeneration chamber from entering the motor chamber.

In the above electric fluid machine, the housing has a partition wall separating the motor chamber and the regeneration chamber, the partition wall has an insertion hole through which the rotating shaft is inserted, and a seal member is provided to seal between the rotating shaft and the insertion hole, and the introduction flow path passes through the partition wall and communicates with a portion of the insertion hole closer to the motor chamber than the seal member.

With this, at least a portion of the air compressed in the first compression section is introduced through the introduction passage into a portion of the insertion hole closer to the motor chamber than the seal member. This makes it easier to prevent water present in the regeneration chamber from entering the motor chamber through the insertion hole.

In the above electric fluid machine, the thrust bearing is disposed between the first radial bearing and the regenerative section, and the housing has a first radial bearing holder that communicates with the motor chamber and holds the first radial bearing, a second radial bearing holder that communicates with the motor chamber and holds the second radial bearing, and a thrust bearing accommodating chamber that communicates with the first radial bearing holder and the insertion hole and accommodates the thrust bearing, and air from the introduction flow path passes through the insertion hole, the thrust bearing accommodating chamber, and the inside of the first radial bearing holder in that order, and is introduced into the motor chamber, and the air introduced into the motor chamber passes through the inside of the second radial bearing holder and is sucked into the second compression section via the intake flow path.

According to this, the thrust bearing is cooled by the air passing through the thrust bearing housing chamber. Then, the first radial bearing is cooled by the air passing inside the first radial bearing holder. Furthermore, the motor is cooled by the air passing through the motor chamber. Then, the second radial bearing is cooled by the air passing inside the second radial bearing holder. Therefore, the first radial bearing, the second radial bearing, the thrust bearing, and the motor can be efficiently cooled by air.

This invention makes it possible to prevent the water present in the regeneration chamber from entering the motor chamber while preventing the entire fuel cell system from becoming too large.

1 is a cross-sectional view of an electric fluid machine according to an embodiment.

One embodiment of an electric fluid machine will be described below with reference to FIG. 1. The electric fluid machine of this embodiment is mounted on a fuel cell vehicle. The fuel cell vehicle is equipped with a fuel cell system that supplies oxygen and hydrogen to a fuel cell stack to generate electricity. The electric fluid machine constitutes part of the fuel cell system and supplies air containing oxygen to the fuel cell stack.

<Basic configuration of electric fluid machine 10>
As shown in Fig. 1, the electric fluid machine 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 first compressor housing 13, a second compressor housing 14, a first intermediate housing 15, a second intermediate housing 16, and a turbine housing 17.

The motor housing 12 is cylindrical. The motor housing 12 has a plate-shaped end wall 12a and a peripheral wall 12b. The peripheral wall 12b extends cylindrically from the outer periphery of the end wall 12a. The opening of the peripheral wall 12b on the opposite side to the end wall 12a is closed by the second compressor housing 14. The end wall 12a and peripheral wall 12b of the motor housing 12 and the second compressor housing 14 define a motor chamber 18. Thus, the housing 11 has a motor chamber 18.

The motor housing 12 has a first radial bearing retaining portion 19. The first radial bearing retaining portion 19 is formed in the center of the end wall 12a of the motor housing 12. Therefore, the housing 11 has the first radial bearing retaining portion 19. The first radial bearing retaining portion 19 is cylindrical. The first radial bearing retaining portion 19 opens to the end face of the end wall 12a of the motor housing 12 on the motor chamber 18 side. Therefore, the inside of the first radial bearing retaining portion 19 is connected to the motor chamber 18.

The motor housing 12 has a communication hole 20. The communication hole 20 is formed in the center of the end wall 12a of the motor housing 12. The communication hole 20 is a circular hole. A first end of the communication hole 20 communicates with the inside of the first radial bearing holder 19. A second end of the communication hole 20 opens to the end face of the end wall 12a of the motor housing 12 opposite the motor chamber 18. The axis of the communication hole 20 coincides with the axis of the first radial bearing holder 19.

The first compressor housing 13 is cylindrical and has an intake port 21. The intake port 21 is a circular hole. The intake port 21 draws in air. The second compressor housing 14 is cylindrical and has an intake passage 22. Thus, the electric fluid machine 10 has an intake passage 22. The intake passage 22 is a circular hole. The first intermediate housing 15 is plate-shaped. The first intermediate housing 15 has a through hole 23. The through hole 23 is formed in the center of the first intermediate housing 15. The first intermediate housing 15 is interposed between the first compressor housing 13 and the second compressor housing 14.

The first compressor housing 13 and the second compressor housing 14 are connected to the first intermediate housing 15 with the axis of the intake port 21, the axis of the intake passage 22, and the axis of the through hole 23 all aligned. The first compressor housing 13 is connected to the first end face 151 of the first intermediate housing 15. The second compressor housing 14 is connected to the second end face 152 of the first intermediate housing 15.

The electric fluid machine 10 includes a first impeller chamber 24, a first discharge chamber 25, and a first diffuser passage 26. The first impeller chamber 24, the first discharge chamber 25, and the first diffuser passage 26 are partitioned between the first compressor housing 13 and the first intermediate housing 15. The first impeller chamber 24 is connected to the suction port 21. The first discharge chamber 25 extends around the axis of the suction port 21 around the periphery of the first impeller chamber 24. The first diffuser passage 26 connects the first impeller chamber 24 and the first discharge chamber 25.

The first compressor housing 13 has a first discharge passage 27. A first end of the first discharge passage 27 is connected to the first discharge chamber 25. A second end of the first discharge passage 27 opens to the outer peripheral surface of the first compressor housing 13.

The electric fluid machine 10 includes a second impeller chamber 28, a second discharge chamber 29, and a second diffuser passage 30. The second impeller chamber 28, the second discharge chamber 29, and the second diffuser passage 30 are partitioned between the second compressor housing 14 and the first intermediate housing 15. The second impeller chamber 28 is connected to the intake passage 22. The second impeller chamber 28 is connected to the first impeller chamber 24 via the through hole 23. The second discharge chamber 29 extends around the axis of the intake passage 22 around the second impeller chamber 28. The second diffuser passage 30 connects the second impeller chamber 28 and the second discharge chamber 29.

The second compressor housing 14 has a second discharge passage 31. A first end of the second discharge passage 31 is connected to the second discharge chamber 29. A second end of the second discharge passage 31 opens to the outer peripheral surface of the second compressor housing 14.

The second compressor housing 14 has a second radial bearing retaining portion 32. The second radial bearing retaining portion 32 is formed in the center of the end face of the second compressor housing 14 on the motor chamber 18 side. Therefore, the housing 11 has the second radial bearing retaining portion 32. The second radial bearing retaining portion 32 is cylindrical. The second radial bearing retaining portion 32 opens to the end face of the second compressor housing 14 on the motor chamber 18 side. Therefore, the inside of the second radial bearing retaining portion 32 is connected to the motor chamber 18.

The inside of the second radial bearing holder 32 is connected to the intake passage 22. Therefore, the intake passage 22 is connected to the motor chamber 18 via the inside of the second radial bearing holder 32. The axis of the second radial bearing holder 32 and the axis of the intake passage 22 are aligned with each other.

The second intermediate housing 16 is cylindrical. The second intermediate housing 16 has a plate-shaped end wall 16a and a peripheral wall 16b. The peripheral wall 16b extends cylindrically from the outer periphery of the end wall 16a. The second intermediate housing 16 is connected to the end wall 12a of the motor housing 12. The opening of the peripheral wall 16b of the second intermediate housing 16 on the opposite side to the end wall 16a is closed by the end wall 12a of the motor housing 12. The end wall 16a and the peripheral wall 16b of the second intermediate housing 16 and the end wall 12a of the motor housing 12 define a thrust bearing accommodating chamber 33. Therefore, the housing 11 has a thrust bearing accommodating chamber 33.

The thrust bearing accommodating chamber 33 is connected to the communication hole 20. Therefore, the thrust bearing accommodating chamber 33 is connected to the inside of the first radial bearing retaining portion 19 via the communication hole 20. And, the thrust bearing accommodating chamber 33 is connected to the motor chamber 18 via the communication hole 20 and the inside of the first radial bearing retaining portion 19.

The second intermediate housing 16 has a through hole 34. The through hole 34 is formed in the center of the end wall 16a of the second intermediate housing 16. The through hole 34 is a circular hole. The through hole 34 penetrates the end wall 16a in the thickness direction. The through hole 34 communicates with the thrust bearing accommodating chamber 33. Therefore, the thrust bearing accommodating chamber 33 communicates with the first radial bearing retaining portion 19 and the through hole 34.

The turbine housing 17 is cylindrical and has a discharge port 35. The discharge port 35 is a circular hole. The turbine housing 17 is connected to the end wall 16a of the second intermediate housing 16 with the axis of the discharge port 35 coinciding with the axis of the insertion hole 34. The discharge port 35 opens on the end face of the turbine housing 17 opposite the second intermediate housing 16.

The electric fluid machine 10 has a regeneration chamber 36, a turbine scroll passage 37, and a communication passage 38. The regeneration chamber 36, the turbine scroll passage 37, and the communication passage 38 are partitioned between the turbine housing 17 and the end wall 16a of the second intermediate housing 16. Thus, the housing 11 has the regeneration chamber 36. The regeneration chamber 36 is connected to the discharge port 35. The turbine scroll passage 37 extends around the axis of the discharge port 35 around the regeneration chamber 36. The communication passage 38 connects the regeneration chamber 36 and the turbine scroll passage 37. The regeneration chamber 36 is connected to the insertion hole 34.

The turbine housing 17 has a supply passage 39. A first end of the supply passage 39 opens to the outer peripheral surface of the turbine housing 17. A second end of the supply passage 39 communicates with the turbine scroll passage 37.

The end wall 12a of the motor housing 12 and the second intermediate housing 16 are interposed between the motor chamber 18 and the regeneration chamber 36. The end wall 12a of the motor housing 12 and the second intermediate housing 16 separate the motor chamber 18 and the regeneration chamber 36. Thus, the end wall 12a of the motor housing 12 and the second intermediate housing 16 are a partition wall 40 that separates the motor chamber 18 and the regeneration chamber 36. Therefore, the housing 11 has a partition wall 40.

The electric fluid machine 10 has a rotating shaft 41. The rotating shaft 41 is accommodated in the housing 11. The rotating shaft 41 passes from the first impeller chamber 24 through the through hole 23, the second impeller chamber 28, the intake passage 22, the second radial bearing holder 32, the motor chamber 18, the first radial bearing holder 19, the communication hole 20, the thrust bearing housing chamber 33, and the insertion hole 34, in that order, to the regeneration chamber 36. Thus, the rotating shaft 41 is inserted through the insertion hole 34. Therefore, the partition wall 40 is formed with the insertion hole 34 through which the rotating shaft 41 is inserted.

The electric fluid machine 10 includes a motor 42. The motor 42 is housed in the motor chamber 18. The motor chamber 18 therefore houses the motor 42. The motor 42 includes a stator 43 and a rotor 44. The stator 43 includes a cylindrical stator core 45 and a coil 46 wound around the stator core 45. The stator core 45 is fixed to the inner circumferential surface of the peripheral wall 12b of the motor housing 12. The rotor 44 is disposed inside the stator core 45 in the motor chamber 18. The rotor 44 rotates integrally with the rotating shaft 41. The rotor 44 includes a rotor core 47 fixed to the rotating shaft 41 and a plurality of permanent magnets (not shown) provided on the rotor core 47. The rotor 44 rotates as a result of the coil 46 being supplied with power controlled by an inverter device (not shown), and the rotating shaft 41 rotates integrally with the rotor 44. The motor 42 therefore rotates the rotating shaft 41.

The electric fluid machine 10 includes a first compression section 51 and a second compression section 52. The first compression section 51 and the second compression section 52 are impellers. The first compression section 51 is accommodated in the first impeller chamber 24. Therefore, the first impeller chamber 24 is a first compression chamber that accommodates the first compression section 51. The second compression section 52 is accommodated in the second impeller chamber 28. Therefore, the second impeller chamber 28 is a second compression chamber that accommodates the second compression section 52. The first compression section 51 and the second compression section 52 are provided at one end of the rotating shaft 41, which is a portion closer to one end than the motor 42. The first compression section 51 and the second compression section 52 rotate integrally with the rotating shaft 41.

The electric fluid machine 10 includes a regenerative unit 53. The regenerative unit 53 is a turbine wheel. The regenerative unit 53 is housed in the regenerative chamber 36. Thus, the regenerative chamber 36 houses the regenerative unit 53. The regenerative unit 53 is provided at the other end of the rotating shaft 41, which is a portion of the rotating shaft 41 closer to the other end than the motor 42. The regenerative unit 53 rotates integrally with the rotating shaft 41. The motor 42 and the second compression unit 52 are provided between the first compression unit 51 and the regenerative unit 53 on the rotating shaft 41.

The electric fluid machine 10 is equipped with a first radial bearing 54. The first radial bearing 54 is disposed inside the first radial bearing holder 19. The first radial bearing holder 19 holds the first radial bearing 54. The first radial bearing 54 supports the portion of the rotating shaft 41 between the regenerative unit 53 and the motor 42 so that the portion can rotate in the radial direction.

The electric fluid machine 10 is equipped with a second radial bearing 55. The second radial bearing 55 is disposed inside the second radial bearing holder 32. The second radial bearing holder 32 holds the second radial bearing 55. The second radial bearing 55 supports the portion of the rotating shaft 41 between the first compression section 51 and the second compression section 52 and the motor 42 so that the portion can rotate in the radial direction. The "radial direction" is a direction perpendicular to the axial direction of the rotating shaft 41.

The rotating shaft 41 is provided with a support portion 56. The support portion 56 protrudes in an annular shape from the outer peripheral surface of the rotating shaft 41. The support portion 56 is disk-shaped. The support portion 56 is fixed to the outer peripheral surface of the rotating shaft 41 in a state where it protrudes in an annular shape radially outward from the outer peripheral surface of the rotating shaft 41. The support portion 56 is disposed in the thrust bearing housing 33. The support portion 56 rotates integrally with the rotating shaft 41.

The electric fluid machine 10 is equipped with a thrust bearing 57. The thrust bearing 57 is accommodated in the thrust bearing accommodation chamber 33. Therefore, the thrust bearing accommodation chamber 33 accommodates the thrust bearing 57. The thrust bearing 57 includes a first thrust bearing portion 57a and a second thrust bearing portion 57b. The first thrust bearing portion 57a and the second thrust bearing portion 57b are arranged to sandwich the support portion 56. The first thrust bearing portion 57a is located closer to the regenerative portion 53 than the support portion 56. The second thrust bearing portion 57b is located closer to the first radial bearing 54 than the support portion 56.

The first thrust bearing portion 57a and the second thrust bearing portion 57b support the support portion 56 so that it can rotate in the thrust direction. Therefore, the thrust bearing 57 is disposed between the first radial bearing 54 and the regeneration portion 53, and supports the rotating shaft 41 so that it can rotate in the thrust direction via the support portion 56. Therefore, the thrust bearing 57 is disposed between the first compression portion 51 and the regeneration portion 53 on the rotating shaft 41. Note that the "thrust direction" is a direction parallel to the axial direction of the rotating shaft 41.

The electric fluid machine 10 is provided with a seal member 58. The seal member 58 seals between the rotating shaft 41 and the insertion hole 34. The seal member 58 prevents air from leaking from the regeneration chamber 36 toward the motor chamber 18. The seal member 58 is, for example, a seal ring.

The electric fluid machine 10 is provided with a bypass passage 59. The bypass passage 59 penetrates the second compressor housing 14 in the radial direction of the rotating shaft 41. A first end of the bypass passage 59 opens to the outer peripheral surface of the second compressor housing 14. A second end of the bypass passage 59 communicates with the suction passage 22.

<Inlet flow path 60>
The electric fluid machine 10 has an introduction passage 60. The introduction passage 60 penetrates the end wall 16a of the second intermediate housing 16 in the radial direction of the rotating shaft 41. Therefore, the introduction passage 60 penetrates the partition wall 40. A first end of the introduction passage 60 opens to the outer circumferential surface of the end wall 16a of the second intermediate housing 16. A second end of the introduction passage 60 communicates with a portion of the insertion hole 34 closer to the motor chamber 18 than the seal member 58. The introduction passage 60 introduces air into a portion of the insertion hole 34 closer to the motor chamber 18 than the seal member 58.

<Fuel Cell System 61>
The electric fluid machine 10 configured as described above constitutes part of a fuel cell system 61 mounted on a fuel cell vehicle. In addition to the electric fluid machine 10, the fuel cell system 61 includes a fuel cell stack 62, a supply pipe 63, and a discharge pipe 64. The fuel cell stack 62 is made up of a plurality of battery cells (not shown). The supply pipe 63 connects the second discharge passage 31 and the fuel cell stack 62. The discharge pipe 64 connects the fuel cell stack 62 and the supply passage 39.

The fuel cell system 61 includes a connection pipe 65 and a branch pipe 66. The connection pipe 65 connects the first exhaust passage 27 and the introduction flow path 60. The branch pipe 66 branches off from the middle of the connection pipe 65. The branch pipe 66 connects the connection pipe 65 and the bypass flow path 59.

[Operation of the embodiment]
Next, the operation of this embodiment will be described.
When the rotor 44 rotates, the first compression section 51, the second compression section 52, and the regeneration section 53 rotate integrally with the rotary shaft 41. When the first compression section 51 rotates, air is drawn into the first impeller chamber 24 from the suction port 21. The air flowing through the suction port 21 is cleaned by an air cleaner (not shown).

The air drawn in from the intake port 21 is compressed by the first compression section 51 in the first impeller chamber 24 and passes through the first diffuser passage 26 before being discharged into the first discharge chamber 25. The first compression section 51 therefore compresses the air as the rotating shaft 41 rotates. The air discharged into the first discharge chamber 25 is then discharged into the connecting pipe 65 via the first exhaust passage 27. A portion of the air discharged into the connecting pipe 65 flows into the bypass passage 59 via the branch pipe 66. The air that flows into the bypass passage 59 is drawn into the second impeller chamber 28 via the intake passage 22.

On the other hand, a portion of the air discharged into the connection pipe 65 flows toward the introduction passage 60 without flowing into the branch pipe 66. Then, the air that flows into the introduction passage 60 from the connection pipe 65 is introduced through the introduction passage 60 into a portion of the insertion hole 34 that is closer to the motor chamber 18 than the seal member 58. Therefore, the introduction passage 60 introduces a portion of the air compressed in the first compression section 51 into the space between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11. The air introduced into the insertion hole 34 passes through the thrust bearing accommodation chamber 33. The thrust bearing 57 is cooled by the air passing through the thrust bearing accommodation chamber 33.

Air that passes through the thrust bearing accommodating chamber 33 passes through the inside of the first radial bearing retaining portion 19 via the communication hole 20. The first radial bearing 54 is cooled by the air passing through the inside of the first radial bearing retaining portion 19. The air that passes through the inside of the first radial bearing retaining portion 19 is introduced into the motor chamber 18. Therefore, air from the introduction flow passage 60 is introduced into the motor chamber 18 via the insertion hole 34, the thrust bearing accommodating chamber 33, the communication hole 20, and the inside of the first radial bearing retaining portion 19. Therefore, the introduction flow passage 60 introduces the air compressed in the first compression section 51 into the motor chamber 18.

The air introduced into the motor chamber 18 passes through the motor chamber 18. The motor 42 is cooled by the air passing through the motor chamber 18. The air passing through the motor chamber 18 passes inside the second radial bearing holder 32. The second radial bearing 55 is cooled by the air passing inside the second radial bearing holder 32. The air that passes inside the second radial bearing holder 32 is sucked into the second impeller chamber 28 through the intake passage 22. Thus, air is sucked into the second compression section 52 from the intake passage 22. Therefore, the intake passage 22 sucks the air introduced into the housing 11 from the introduction passage 60 into the second compression section 52 after cooling the first radial bearing 54, the second radial bearing 55, the thrust bearing 57, and the motor 42.

In this way, the air from the intake passage 60 passes through the insertion hole 34, the thrust bearing housing chamber 33, and the inside of the first radial bearing holder 19, and is introduced into the motor chamber 18. The air introduced into the motor chamber 18 passes through the inside of the second radial bearing holder 32 and is sucked into the second compression section 52 via the intake passage 22.

The air drawn in from the intake passage 22 is compressed by the second compression section 52 in the second impeller chamber 28 and passes through the second diffuser passage 30 before being discharged into the second discharge chamber 29. The air discharged into the second discharge chamber 29 is discharged into the supply pipe 63 via the second exhaust passage 31. The air discharged into the supply pipe 63 is supplied to the fuel cell stack 62 via the supply pipe 63. Therefore, the second compression section 52 compresses the air compressed by the first compression section 51 as the rotating shaft 41 rotates, and supplies the air to the fuel cell stack 62.

The air supplied to the fuel cell stack 62 is used to make the fuel cell stack 62 generate electricity. The air passing through the fuel cell stack 62 is then discharged to the exhaust pipe 64 as exhaust gas from the fuel cell stack 62. The exhaust gas from the fuel cell stack 62 is supplied to the turbine scroll passage 37 via the exhaust pipe 64 and the supply passage 39. The exhaust gas supplied to the turbine scroll passage 37 is introduced into the regeneration chamber 36 through the communication passage 38.

The regeneration unit 53 rotates due to the exhaust gas introduced into the regeneration chamber 36. In addition to being rotated by the motor 42, the rotating shaft 41 also rotates due to the rotation of the regeneration unit 53, which rotates due to the exhaust gas discharged from the fuel cell stack 62. The rotation of the regeneration unit 53 due to the exhaust gas discharged from the fuel cell stack 62 assists the drive of the motor 42. Therefore, the regeneration unit 53 rotates due to the exhaust gas discharged from the fuel cell stack 62 and assists the drive of the motor 42. The exhaust gas that has passed through the regeneration chamber 36 is discharged to the outside from the discharge port 35.

In the fuel cell system 61, the exhaust gas discharged from the fuel cell stack 62 contains water that is generated when the fuel cell stack 62 generates electricity. Therefore, the exhaust gas introduced from the fuel cell stack 62 to the regeneration chamber 36 contains water. At this time, the air introduced into the motor chamber 18 is compressed and pressurized by the first compression section 51. Therefore, the pressure in the motor chamber 18 increases when the air compressed by the first compression section 51 is introduced into the motor chamber 18 through the introduction passage 60. This prevents the pressure in the motor chamber 18 from falling below the pressure in the regeneration chamber 36. Therefore, the water present in the regeneration chamber 36 is prevented from entering the motor chamber 18 through the insertion hole 34.

[Effects of the embodiment]
The above embodiment can provide the following effects.
(1) The temperature of the air compressed by the first compression section 51 is lower than the temperature of the air compressed by the second compression section 52. The air compressed by the first compression section 51 is introduced into the housing 11 between the first impeller chamber 24 and the regeneration chamber 36 through the introduction passage 60. Therefore, compared to the case where, for example, a part of the air compressed by the second compression section 52 is introduced into the housing 11, air with a lower temperature can be introduced into the housing 11. The air introduced into the housing 11 from the introduction passage 60 cools the first radial bearing 54, the second radial bearing 55, the thrust bearing 57, and the motor 42, and is then sucked into the second compression section 52 through the intake passage 22. The air sucked into the second compression section 52 through the intake passage 22 is compressed by the second compression section 52. The air compressed by the second compression section 52 is supplied to the fuel cell stack 62. Therefore, unlike the conventional technology, it is not necessary to use an intercooler to cool a portion of the air supplied to the fuel cell stack 62 before introducing it into the housing 11, and the intercooler can be eliminated, thereby preventing the fuel cell system 61 from becoming larger overall.

The air introduced between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11 is compressed and pressurized by the first compression section 51. Therefore, the air compressed by the first compression section 51 is introduced between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11 through the introduction passage 60, and the pressure between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11 increases. Here, the motor chamber 18 is located between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11. Therefore, the pressure in the motor chamber 18 is prevented from falling below the pressure in the regeneration chamber 36. Therefore, the water present in the regeneration chamber 36 is prevented from entering the motor chamber 18. As a result, it is possible to prevent the fuel cell system 61 from becoming larger overall while preventing the water present in the regeneration chamber 36 from entering the motor chamber 18.

(2) The introduction passage 60 is connected to a portion of the insertion hole 34 closer to the motor chamber 18 than the seal member 58. This allows the air compressed in the first compression section 51 to be introduced through the introduction passage 60 into a portion of the insertion hole 34 closer to the motor chamber 18 than the seal member 58. This makes it easier to prevent water present in the regeneration chamber 36 from entering the motor chamber 18 through the insertion hole 34.

(3) The air from the introduction flow passage 60 passes through the insertion hole 34, the thrust bearing accommodation chamber 33, and the inside of the first radial bearing holding portion 19 in that order, and is introduced into the motor chamber 18. The air introduced into the motor chamber 18 passes through the inside of the second radial bearing holding portion 32 and is sucked into the second compression section 52 through the intake flow passage 22. According to this, the thrust bearing 57 is cooled by the air passing through the thrust bearing accommodation chamber 33. Next, the first radial bearing 54 is cooled by the air passing through the inside of the first radial bearing holding portion 19. Furthermore, the motor 42 is cooled by the air passing through the motor chamber 18. Next, the second radial bearing 55 is cooled by the air passing through the inside of the second radial bearing holding portion 32. Therefore, the first radial bearing 54, the second radial bearing 55, the thrust bearing 57, and the motor 42 can be efficiently cooled by air.

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

In the embodiment, the electric fluid machine 10 may be configured not to include the bypass flow passage 59. In this case, all of the air compressed in the first compression section 51 is introduced between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11 via the introduction flow passage 60. In short, the introduction flow passage 60 only needs to introduce at least a portion of the air compressed in the first compression section 51 between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11.

In the embodiment, the second end of the introduction passage 60 does not have to communicate with a portion of the insertion hole 34 closer to the motor chamber 18 than the seal member 58. For example, the second end of the introduction passage 60 may communicate with the motor chamber 18. In short, the introduction passage 60 only needs to introduce the air compressed by the first compression section 51 between the first impeller chamber 24 and the regeneration chamber 36 in the housing 11.

In the embodiment, the second compression unit 52 may be disposed, for example, between the motor 42 and the regeneration unit 53. In short, the second compression unit 52 only needs to be provided between the first compression unit 51 and the regeneration unit 53 on the rotating shaft 41.

In the embodiment, the thrust bearing 57 may be disposed, for example, between the second compression section 52 and the second radial bearing 55. In short, it is sufficient that the thrust bearing 57 is disposed between the first compression section 51 and the regeneration section 53 on the rotating shaft 41.

In the embodiment, the first compression section 51 and the second compression section 52 are impellers, but this is not limited thereto, and other types, such as scroll types, may be used as the first compression section 51 and the second compression section 52. In short, the first compression section 51 and the second compression section 52 are not limited to impellers.

In the embodiment, the regenerative unit 53 is a turbine wheel, but this is not limited thereto. For example, other types of regenerative units, such as a scroll type, may be used. In short, the regenerative unit 53 is not limited to a turbine wheel.

In the embodiment, the electric fluid machine 10 does not have to be mounted on a fuel cell vehicle. In other words, the electric fluid machine 10 is not limited to being mounted on a vehicle.

10...electric fluid machine, 11...housing, 18...motor chamber, 19...first radial bearing holder, 22...suction flow path, 24...first impeller chamber which is the first compression chamber, 28...second impeller chamber which is the second compression chamber, 32...second radial bearing holder, 33...thrust bearing housing chamber, 34...through hole, 36...regeneration chamber, 40...partition wall, 41...rotating shaft, 42...motor, 51...first compression section, 52...second compression section, 53...regeneration section, 54...first radial bearing, 55...second radial bearing, 57...thrust bearing, 58...sealing member, 60...inlet flow path, 61...fuel cell system, 62...fuel cell stack.

Claims (3)

An electric fluid machine that constitutes a part of a fuel cell system and supplies air to a fuel cell stack,
A rotation axis;
A motor that rotates the rotary shaft;
a first compression section that compresses air as the rotary shaft rotates;
a second compression unit that compresses the air compressed by the first compression unit as the rotating shaft rotates and supplies the air to the fuel cell stack;
a regeneration unit that is rotated by exhaust gas discharged from the fuel cell stack to assist in driving the motor;
a housing having a first compression chamber that accommodates the first compression section, a second compression chamber that accommodates the second compression section, a motor chamber that accommodates the motor, and a regeneration chamber that accommodates the regeneration section,
the first compression portion is provided at one end of the rotating shaft that is closer to one end than the motor,
the regenerative unit is provided at the other end of the rotating shaft that is on the other end side of the motor,
the motor and the second compression unit are provided on the rotary shaft between the first compression unit and the regeneration unit,
a first radial bearing that supports the rotating shaft between the regenerator and the motor in a radial direction;
a second radial bearing that supports the rotating shaft between the first compression unit and the motor in a radial direction;
a thrust bearing disposed between the first compression section and the regeneration section in the rotating shaft and configured to support the rotating shaft in a thrust direction,
an introduction passage that introduces at least a portion of the air compressed in the first compression section into a space between the first compression chamber and the regeneration chamber in the housing;
an intake passage through which air introduced into the housing from the intake passage cools the first radial bearing, the second radial bearing, the thrust bearing, and the motor, and then is sucked into the second compression section. The housing has a partition wall that separates the motor chamber and the regeneration chamber,
The partition wall has an insertion hole through which the rotation shaft is inserted,
a seal member that seals between the rotating shaft and the insertion hole,
The electric fluid machine according to claim 1 , wherein the introduction passage passes through the partition wall and communicates with a portion of the insertion hole closer to the motor chamber than the seal member. the thrust bearing is disposed between the first radial bearing and the regenerative unit,
The housing includes:
a first radial bearing holding portion that communicates with the motor chamber and holds the first radial bearing;
a second radial bearing holder that communicates with the motor chamber and holds the second radial bearing;
a thrust bearing accommodating chamber that communicates with the first radial bearing retaining portion and the insertion hole and accommodates the thrust bearing,
3. The electric fluid machine according to claim 2, wherein air from the intake passage passes through the insertion hole, through the thrust bearing accommodating chamber, and the inside of the first radial bearing retaining portion in that order, before being introduced into the motor chamber, and the air introduced into the motor chamber passes through the inside of the second radial bearing retaining portion and is sucked into the second compression section via the intake passage.