JP2023182162A - centrifugal compressor - Google Patents

Abstract

To efficiently cool a coil.SOLUTION: A part of each path 69 is formed in a protrusion part 60, through which air suctioned into a shaft path 65 from a suction port flows toward a second coil end 36b. Therefore, air introduced into a motor chamber 18 from each path 69 easily flows toward the second coil end 36b. Therefore, the second coil end 36b is easily cooled by the air introduced into the motor chamber 18.SELECTED DRAWING: Figure 5

Description

The present invention relates to a centrifugal compressor.

A centrifugal compressor includes a rotating shaft, a motor, an impeller, and a housing. The motor rotates the rotating shaft. The impeller compresses air by rotating together with the rotating shaft. The housing has an impeller chamber, a motor chamber, and an inlet. The impeller chamber houses the impeller. The motor chamber houses the motor. The suction port sucks air into the impeller chamber.

The motor includes a stator and a rotor. The stator has a stator core and a coil. The stator is fixed to the inner peripheral surface of the housing. The coil is wound around the stator core. A coil end, which is a part of the coil end, protrudes from the end surface of the stator core. Therefore, the stator has coil ends. The rotor is located inside the stator. The rotor rotates integrally with the rotating shaft.

By the way, in such a centrifugal compressor, since heat is generated in the coil, it is desired to cool the coil. Therefore, as in Patent Document 1, for example, a centrifugal compressor may include an axial path and a path. The axial path extends inside the rotating shaft in the axial direction of the rotating shaft. The axial passage opens toward the suction port. The path communicates with the axial path. The path extends from the axial path in the radial direction of the rotating shaft. The path communicates with the motor chamber. A portion of the air from the inlet is introduced into the shaft and flows through the shaft and the path. The air flowing through the path is accelerated by the centrifugal force caused by the rotation of the rotating shaft, and is introduced from the path into the motor chamber. By introducing air into the motor chamber in this manner, the coil is cooled by the air introduced into the motor chamber.

Patent No. 6968253

However, in such a centrifugal compressor, it is desired that the coil be efficiently cooled by air introduced into the motor chamber.

A centrifugal compressor that solves the above problems includes a rotating shaft, a motor that rotates the rotating shaft, an impeller that compresses air by rotating integrally with the rotating shaft, an impeller chamber that accommodates the impeller, and a motor that rotates the rotating shaft. A housing having a motor chamber for accommodating a motor, and a suction port for sucking air into the impeller chamber, and the motor includes a stator core fixed to the housing, and a part of a coil wound around the stator core. and a stator having a coil end protruding from an end surface of the stator core, and a rotor disposed inside the stator and rotating integrally with the rotating shaft, and opening toward the suction port, an axial path extending inside the rotating shaft in the axial direction of the rotating shaft; and a path that communicates with the axial path, extends from the axial path in the radial direction of the rotating shaft, and communicates with the motor chamber. The centrifugal compressor is equipped with a centrifugal compressor, wherein the rotating shaft has a protrusion that protrudes toward the coil end from a portion of the outer circumferential surface of the rotating shaft that faces the coil end, and the protrusion includes: A part of the path is formed through which air sucked into the axial path from the suction port flows toward the coil end.

According to this, a part of the path through which the air sucked into the shaft path from the suction port flows toward the coil end is formed in the protrusion, so that the air introduced into the motor chamber from the path flows into the coil end. It becomes easier to flow towards the target. Therefore, the coil end is easily cooled by the air introduced into the motor chamber. As a result, the coil can be efficiently cooled.

In the above-mentioned centrifugal compressor, the protrusion may have an opposing surface facing the coil end, and the path may penetrate through the protrusion and open to the opposing surface.
According to this, since the path passes through the protrusion and opens on the opposing surface of the protrusion that faces the coil end, the air introduced into the motor chamber from the path tends to flow toward the coil end. Therefore, the coil end is easily cooled by the air introduced into the motor chamber. As a result, the coil can be efficiently cooled.

The centrifugal compressor described above includes a radial bearing that rotatably supports the rotating shaft with respect to the housing, the housing has a cylindrical radial bearing holding part that holds the radial bearing, and the radial bearing holding part that holds the radial bearing. The outer circumferential surface of the portion is located inside the coil end when viewed from the axial direction of the rotating shaft, and the opposing surface is located within the coil end when viewed from the axial direction of the rotating shaft. It is preferable that it be located between the outer peripheral surface of the radial bearing holding part and the outer circumferential surface of the radial bearing holding part.

According to this, for example, when the opposing surface of the protruding part is seen from the axial direction of the rotating shaft, compared to the case where the opposing surface of the protruding part overlaps the radial bearing holding part in the axial direction of the rotating shaft, the protruding part is The opposing surface can be brought as close to the coil end as possible. Therefore, the air introduced into the motor chamber from the path is more likely to flow toward the coil end, making it easier for the coil end to be further cooled by the air introduced into the motor chamber. As a result, the coil can be cooled more efficiently.

In the centrifugal compressor, the opposing surface preferably overlaps the end surface of the stator core in the axial direction of the rotating shaft when viewed from the axial direction of the rotating shaft.
According to this, for example, compared to a case where the opposing surface of the protruding part is located radially inward from the inner circumferential surface of the stator core when viewed from the axial direction of the rotating shaft, the opposing surface of the protruding part can be placed as close to the coil end as possible. Therefore, the air introduced into the motor chamber from the path is more likely to flow toward the coil end, making it easier for the coil end to be further cooled by the air introduced into the motor chamber. As a result, the coil can be cooled more efficiently.

In the centrifugal compressor described above, it is preferable that the protruding portion is formed with a recessed portion for adjusting the rotational balance of the rotating shaft. The protrusion that protrudes from the outer circumferential surface of the rotating shaft is suitable as a part for forming a recess in order to adjust the rotational balance of the rotating shaft.

In the centrifugal compressor, the rotor includes a cylindrical member and a magnetic body fixed inside the cylindrical member, and the rotating shaft is located on both sides of the magnetic body in the axial direction of the cylindrical member. The impeller includes a first shaft member and a second shaft member provided in the first shaft member, the impeller is connected to the first shaft member, and the shaft passage passes through the first shaft member and the magnetic body, and the impeller is connected to the first shaft member and the The protruding portion may extend into the second shaft member and protrude from the outer circumferential surface of the second shaft member toward the coil end.

According to this, the magnetic body can be cooled by the air flowing through the axial path. Therefore, in addition to the coil, the magnetic body can also be efficiently cooled by air, so that the durability of the motor can be improved.

The centrifugal compressor described above includes a radial bearing that rotatably supports the rotating shaft with respect to the housing, the housing has a cylindrical radial bearing holding part that holds the radial bearing, and the radial bearing holding part that holds the radial bearing. It is preferable that a cooling passage is formed in the part, into which air introduced into the motor chamber from the path flows.

According to this, heat exchange is performed between the air flowing through the cooling passage and the radial bearing via the radial bearing holding portion, so that the radial bearing can be cooled by the air. Furthermore, the more air flows through the cooling passage, the more difficult it is for the air to pass through the inside of the radial bearing holding part, thereby suppressing foreign matter from entering the inside of the radial bearing holding part together with the air. Therefore, the problem of the radial bearing being worn out by foreign matter can be easily avoided, and the durability of the radial bearing can be improved.

In the above centrifugal compressor, it is preferable that the radial bearing holding part has a plurality of cooling passages formed at intervals in a circumferential direction of the radial bearing holding part.
According to this, for example, compared to a case where only one cooling passage is formed in the radial bearing holding part, the entire radial bearing can be more easily cooled uniformly in the circumferential direction of the radial bearing holding part. Therefore, the radial bearing can be efficiently cooled.

According to this invention, the coil can be efficiently cooled.

It is a sectional view of the centrifugal compressor in an embodiment. FIG. 2 is an enlarged cross-sectional view of a portion of the centrifugal compressor. FIG. 2 is an enlarged cross-sectional view of a portion of the centrifugal compressor. FIG. 2 is an enlarged cross-sectional view of a portion of the centrifugal compressor. FIG. 2 is an enlarged cross-sectional view of a portion of the centrifugal compressor. FIG. 2 is a sectional view of a centrifugal compressor.

An embodiment of a centrifugal compressor will be described below with reference to FIGS. 1 to 6. The centrifugal compressor of this embodiment is installed in a fuel cell vehicle. Centrifugal compressors compress air.
<Basic configuration of centrifugal compressor 10>
As shown in FIG. 1, the centrifugal compressor 10 includes a housing 11. As shown in FIG. Housing 11 is made of metal material. The housing 11 is made of aluminum, for example. Housing 11 is cylindrical. The housing 11 includes a motor housing 12 , a compressor housing 13 , a turbine housing 14 , a first plate 15 , a second plate 16 , and a seal plate 17 .

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 in a cylindrical shape from the outer periphery of the end wall 12a. The first plate 15 is connected to the opening side end of the peripheral wall 12b of the motor housing 12. The first plate 15 closes an opening in the peripheral wall 12b of the motor housing 12. A motor chamber 18 is defined by the end wall 12a and peripheral wall 12b of the motor housing 12 and the first plate 15. Therefore, the housing 11 has a motor chamber 18.

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

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

The first plate 15 has a first radial bearing holding portion 21 . Therefore, the housing 11 has the first radial bearing holding part 21. The first radial bearing holding portion 21 has a cylindrical shape. The first radial bearing holding portion 21 projects into the motor chamber 18 from the center of the end surface 15b of the first plate 15 on the motor housing 12 side. The first radial bearing holding portion 21 communicates with the motor chamber 18 . The first radial bearing holding portion 21 penetrates the first plate 15 and opens to the bottom surface 15h of the second recess 15d. Therefore, the first radial bearing holding portion 21 communicates with the thrust bearing housing chamber 19 . The axis of the first radial bearing holding part 21 coincides with the axis of the first recess 15c and the axis of the second recess 15d.

Compressor housing 13 is cylindrical. The compressor housing 13 has a circular suction port 22 . Therefore, the housing 11 has an inlet 22 . The compressor housing 13 is connected to the end surface 15a of the first plate 15 with the axis of the suction port 22 aligned with the axis of the shaft insertion hole 17h of the seal plate 17. The suction port 22 is open at an end surface of the compressor housing 13 on the opposite side from the first plate 15 .

The centrifugal compressor 10 includes an impeller chamber 23, a discharge chamber 24, and a compressor diffuser flow path 25. The impeller chamber 23, the discharge chamber 24, and the compressor diffuser passage 25 are formed between the compressor housing 13 and the seal plate 17. Therefore, the housing 11 has an impeller chamber 23. Seal plate 17 separates impeller chamber 23 from thrust bearing housing chamber 19 . The impeller chamber 23 communicates with the suction port 22 . The impeller chamber 23 has a substantially truncated conical hole shape whose diameter gradually increases as it moves away from the suction port 22. The discharge chamber 24 extends around the axis of the suction port 22 around the impeller chamber 23 . The compressor diffuser flow path 25 communicates the impeller chamber 23 and the discharge chamber 24. The impeller chamber 23 communicates with the shaft insertion hole 17h of the seal plate 17.

As shown in FIG. 3, the motor housing 12 has a second radial bearing holding portion 26. As shown in FIG. Therefore, the housing 11 has the second radial bearing holding part 26. The second radial bearing holding portion 26 has a cylindrical shape. The second radial bearing holding portion 26 projects into the motor chamber 18 from the center of the inner surface of the end wall 12 a of the motor housing 12 . The second radial bearing holding portion 26 communicates with the motor chamber 18 . The inner side of the second radial bearing holding portion 26 penetrates the end wall 12a of the motor housing 12 and opens to the outer surface of the end wall 12a. The axis of the first radial bearing holder 21 and the axis of the second radial bearing holder 26 are aligned.

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

Turbine housing 14 is cylindrical. The turbine housing 14 has a discharge port 27 in the shape of a circular hole. The turbine housing 14 is connected to an end surface 16a of the second plate 16 opposite to the motor housing 12, with the axis of the discharge port 27 coinciding with the axis of the shaft insertion hole 16h of the second plate 16. The discharge port 27 opens at an end surface of the turbine housing 14 on the opposite side to the second plate 16 .

The centrifugal compressor 10 includes a turbine chamber 28, a turbine scroll passage 29, and a communication passage 30. The turbine chamber 28, the turbine scroll passage 29, and the communication passage 30 are formed between the turbine housing 14 and the end surface 16a of the second plate 16. The turbine chamber 28 communicates with the discharge port 27 . The turbine scroll passage 29 extends around the axis of the discharge port 27 around the turbine chamber 28 . The communication passage 30 communicates the turbine chamber 28 and the turbine scroll flow path 29. The turbine chamber 28 communicates with the shaft insertion hole 16h of the second plate 16.

As shown in FIG. 1, the centrifugal compressor 10 includes a motor 31. The motor 31 is housed in the motor chamber 18. Therefore, the motor chamber 18 accommodates the motor 31. The motor 31 is housed within the housing 11.

The motor 31 includes a stator 32 and a rotor 33. The stator 32 includes a cylindrical stator core 34 and a coil 35. Coil 35 is wound around stator core 34. The stator core 34 is fixed to the inner peripheral surface of the peripheral wall 12b of the motor housing 12. Therefore, stator 32 is fixed to housing 11. Coil ends 36, which are part of the coil 35, protrude from both end surfaces of the stator core 34, respectively. Therefore, the stator 32 has a coil end 36 that is part of the coil 35 and protrudes from the end surface of the stator core 34. In the following description, the coil end 36 located on the first plate 15 side in the stator core 34 will be referred to as a "first coil end 36a." Further, the coil end 36 located on the end wall 12a side of the motor housing 12 in the stator core 34 will be referred to as a "second coil end 36b."

The rotor 33 is arranged inside the stator 32. The rotor 33 includes a cylindrical member 41 and a permanent magnet 42 that is a magnetic material. The cylindrical member 41 is made of, for example, a titanium alloy. The cylindrical member 41 has a cylindrical shape in which the axis of the cylindrical member 41 extends linearly.

Permanent magnet 42 has a cylindrical shape. The permanent magnet 42 is arranged inside the cylindrical member 41. The axis of the permanent magnet 42 coincides with the axis of the cylindrical member 41. The permanent magnet 42 is press-fitted into the inner peripheral surface of the cylindrical member 41. Therefore, the permanent magnet 42 is fixed inside the cylindrical member 41. The permanent magnet 42 is magnetized in the radial direction of the permanent magnet 42. Specifically, the permanent magnet 42 has a cylindrical shape that is magnetized in the radial direction of the permanent magnet 42 and has an N pole and an S pole on both sides of the permanent magnet 42 in the radial direction.

The length of the permanent magnet 42 in the direction in which the axis extends is shorter than the length of the cylindrical member 41 in the direction in which the axis extends. Both end surfaces of the permanent magnet 42 are located inside the cylindrical member 41. Therefore, both end portions of the cylindrical member 41 located in the axial direction protrude in the axial direction with respect to both end surfaces of the permanent magnet 42, respectively. Both end portions of the cylindrical member 41 protrude in the axial direction relative to both end surfaces of the stator core 34, respectively.

The centrifugal compressor 10 includes a rotating shaft 40. The rotating shaft 40 includes a first shaft member 44 and a second shaft member 45. The first shaft member 44 and the second shaft member 45 are provided on both sides of the cylindrical member 41 with the permanent magnet 42 in between in the axial direction. The first shaft member 44 and the second shaft member 45 are made of iron, for example.

The first shaft member 44 has a cylindrical shape. The first end of the first shaft member 44 is inserted inside the first end of the cylindrical member 41 . The first end of the first shaft member 44 is press-fitted into the inner peripheral surface of the first end of the cylindrical member 41 . Therefore, the first shaft member 44 is fixed to the cylinder member 41. The axis of the first shaft member 44 coincides with the axis of the cylinder member 41. The second end of the first shaft member 44 projects from the motor chamber 18 into the impeller chamber 23 through the inside of the first radial bearing holding section 21, the thrust bearing housing chamber 19, and the shaft insertion hole 17h. .

The second shaft member 45 has a cylindrical shape. The first end of the second shaft member 45 is inserted inside the second end of the cylindrical member 41. The first end of the second shaft member 45 is press-fitted into the inner circumferential surface of the second end of the cylindrical member 41 . Therefore, the second shaft member 45 is fixed to the cylinder member 41. The axis of the second shaft member 45 coincides with the axis of the cylinder member 41. The second end of the second shaft member 45 projects from the motor chamber 18 into the turbine chamber 28, passing through the inside of the second radial bearing holding portion 26 and the shaft insertion hole 16h.

The axis of the first shaft member 44 and the axis of the second shaft member 45 coincide. The axial direction of the first shaft member 44 and the axial direction of the second shaft member 45 are the axial directions of the rotating shaft 40. The radial direction of the first shaft member 44 and the radial direction of the second shaft member 45 are the radial directions of the rotating shaft 40. The first shaft member 44 and the second shaft member 45 rotate integrally with the cylinder member 41. Therefore, the rotor 33 rotates integrally with the rotating shaft 40.

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

The centrifugal compressor 10 includes a support section 48 . The support portion 48 projects annularly from the outer peripheral surface of the first shaft member 44 . The support portion 48 has a disk shape. The support portion 48 is fixed to the outer circumferential surface of the first shaft member 44 in a state in which it annularly protrudes radially outward from the outer circumferential surface of the first shaft member 44 . Therefore, the support portion 48 is separate from the first shaft member 44. The support portion 48 is arranged within the thrust bearing housing chamber 19 . The support portion 48 rotates integrally with the first shaft member 44 .

The centrifugal compressor 10 includes an impeller 49. The impeller 49 is attached to the second end of the first shaft member 44 . Therefore, the impeller 49 is connected to the first shaft member 44. The impeller 49 rotates integrally with the first shaft member 44 . Therefore, the impeller 49 rotates integrally with the rotating shaft 40. The impeller 49 is arranged closer to the second end of the first shaft member 44 than the support portion 48 of the first shaft member 44 is. The impeller 49 has a cylindrical shape whose diameter gradually decreases from the back surface toward the front end surface. The impeller 49 is housed in the impeller chamber 23. Therefore, the impeller chamber 23 accommodates the impeller 49. The outer edge of the impeller 49 extends along the inner peripheral surface of the impeller chamber 23. The impeller 49 compresses air by rotating integrally with the rotating shaft 40.

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

As shown in FIG. 4, the centrifugal compressor 10 includes a first radial bearing 51 and a second radial bearing 52. The first radial bearing 51 has a cylindrical shape. The first radial bearing 51 is held by the first radial bearing holding part 21. Therefore, the first radial bearing holding section 21 is a radial bearing holding section that holds the first radial bearing 51. The second radial bearing 52 has a cylindrical shape. The second radial bearing 52 is held by the second radial bearing holding part 26. Therefore, the second radial bearing holding section 26 is a radial bearing holding section that holds the second radial bearing 52.

The first radial bearing 51 rotatably supports the first shaft member 44 with respect to the housing 11 in the radial direction. The second radial bearing 52 rotatably supports the second shaft member 45 with respect to the housing 11 in the radial direction. The first radial bearing 51 and the second radial bearing 52 are radial bearings that rotatably support the rotating shaft 40 in the radial direction with respect to the housing 11 at positions on both sides of the rotor 33 in the axial direction of the rotating shaft 40. . Note that the "radial direction" is a direction perpendicular to the axial direction of the rotating shaft 40. Therefore, the "radial direction" is the radial direction of the rotating shaft 40.

As shown in FIG. 2, the centrifugal compressor 10 includes a thrust bearing 53. The thrust bearing 53 is housed in the thrust bearing housing chamber 19 . Therefore, the thrust bearing accommodation chamber 19 accommodates the thrust bearing 53. The thrust bearing 53 includes a first thrust bearing part 53a and a second thrust bearing part 53b. The first thrust bearing part 53a and the second thrust bearing part 53b are arranged so as to sandwich the support part 48 therebetween. The first thrust bearing portion 53a is located closer to the impeller 49 with respect to the support portion 48. The second thrust bearing portion 53b is located closer to the first radial bearing 51 with respect to the support portion 48.

The first thrust bearing section 53a and the second thrust bearing section 53b rotatably support the support section 48 in the thrust direction. Therefore, the thrust bearing 53 rotatably supports the rotating shaft 40 in the thrust direction between the impeller 49 and the first radial bearing 51 via the support portion 48 . Note that the "thrust direction" is a direction parallel to the axial direction of the rotating shaft 40. In this way, the rotating shaft 40 is rotatably supported by the housing 11.

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

When the rotor 33 rotates, the first shaft member 44 and the second shaft member 45 rotate integrally with the rotor 33. Therefore, the motor 31 rotates the rotating shaft 40. As the first shaft member 44 and the second shaft member 45 rotate, the impeller 49 and the turbine wheel 50 rotate. When the impeller 49 rotates, air is sucked into the impeller chamber 23 from the suction port 22. Therefore, the suction port 22 sucks air into the impeller chamber 23. Note that the air flowing through the suction port 22 is cleaned by an air cleaner (not shown).

Air taken in from the suction port 22 is compressed by the impeller 49 in the impeller chamber 23, passes through the compressor diffuser passage 25, and is discharged from the discharge chamber 24 as compressed air to the supply passage 57. The air discharged from the discharge chamber 24 to the supply channel 57 is supplied to the fuel cell stack 56 via the supply channel 57. The air supplied to the fuel cell stack 56 is used for the fuel cell stack 56 to generate electricity. Thereafter, the air passing through the fuel cell stack 56 is discharged to the exhaust flow path 58 as exhaust from the fuel cell stack 56 .

Exhaust gas from the fuel cell stack 56 is drawn into the turbine scroll flow path 29 via the exhaust flow path 58 . Exhaust gas from the fuel cell stack 56 sucked into the turbine scroll passage 29 is introduced into the turbine chamber 28 through the communication passage 30. The turbine wheel 50 is rotated by exhaust gas from the fuel cell stack 56 introduced into the turbine chamber 28 . The rotor 33 is rotated not only by the rotation driven by the motor 31 but also by the rotation of the turbine wheel 50 which is rotated by the exhaust gas from the fuel cell stack 56 . The rotation of the rotor 33 is assisted by the rotation of the turbine wheel 50 due to the exhaust gas from the fuel cell stack 56. The exhaust gas that has passed through the turbine chamber 28 is discharged to the outside from the discharge port 27.

<Second radial bearing holding part 26>
As shown in FIG. 5, the second radial bearing holding portion 26 is inserted inside the second coil end 36b. Therefore, the outer peripheral surface of the second radial bearing holding portion 26 is located inside the coil end 36 when viewed from the axial direction of the rotating shaft 40. The outer peripheral surface of the second radial bearing holding portion 26 is spaced apart from the second coil end 36b. The distal end surface of the second radial bearing holding portion 26 overlaps the end surface of the stator core 34 in the axial direction of the rotating shaft 40 . The distal end surface of the second radial bearing holding portion 26 is spaced apart from the end surface of the stator core 34.

<Protruding portion 60>
The rotating shaft 40 has a protrusion 60 . The protruding portion 60 protrudes toward the second coil end 36b from a portion of the outer peripheral surface of the second shaft member 45 that faces the second coil end 36b. Therefore, the protruding portion 60 protrudes from the outer peripheral surface of the second shaft member 45 toward the coil end 36. In this way, the protruding portion 60 protrudes toward the coil end 36 from a portion of the outer circumferential surface of the rotating shaft 40 that faces the coil end 36 . The protrusion 60 has an annular shape. The protrusion 60 extends from the outer peripheral surface of the second shaft member 45 in the radial direction of the rotating shaft 40 .

The protrusion 60 is located inside the second coil end 36b. The protruding portion 60 protrudes from the outer circumferential surface of the second shaft member 45 toward between the distal end surface of the second radial bearing holding portion 26 and the end surface of the stator core 34 . A portion of the protruding portion 60 faces the distal end surface of the second radial bearing holding portion 26 in the axial direction of the rotating shaft 40 . The outer peripheral surface of the protrusion 60 is a facing surface 60a that faces the second coil end 36b in the radial direction of the rotating shaft 40. Therefore, the protrusion 60 has a facing surface 60a facing the coil end 36. The opposing surface 60a of the protruding portion 60 is located between the second coil end 36b and the outer peripheral surface of the second radial bearing holding portion 26 when viewed from the axial direction of the rotating shaft 40. The opposing surface 60a of the protrusion 60 is spaced apart from the second coil end 36b. The protruding portion 60 is spaced apart from the distal end surface of the second radial bearing holding portion 26 . The outer peripheral portion of the protrusion 60 faces the end surface of the stator core 34 in the axial direction of the rotating shaft 40 . The opposing surface 60a of the protrusion 60 overlaps the end surface of the stator core 34 in the axial direction of the rotating shaft 40 when viewed from the axial direction of the rotating shaft 40. The protrusion 60 is spaced apart from the end surface of the stator core 34.

A recess 61 is formed in the protrusion 60 . The recess 61 is formed on the end surface of the protrusion 60 located on the stator core 34 side. The recess 61 is formed in an end face of the protrusion 60 located on the stator core 34 side at a portion facing the end face of the stator core 34 in the axial direction of the rotating shaft 40 . The recess 61 adjusts the rotational balance of the rotating shaft 40.

<Axis path 65>
As shown in FIG. 1, the centrifugal compressor 10 includes an axial path 65. The axial path 65 has a first axial path 66 , a second axial path 67 , and a third axial path 68 . The first axial passage 66 passes through the inside of the first axial member 44 in the axial direction of the first axial member 44 . The first axial path 66 has a circular hole shape. A first end of the first shaft passage 66 opens at the second end of the first shaft member 44 and communicates with the suction port 22 . Therefore, the axial passage 65 is open toward the suction port 22.

The second axial path 67 passes through the inside of the permanent magnet 42 in the axial direction of the permanent magnet 42 . Therefore, the axial path 65 penetrates the inside of the permanent magnet 42. The second axial path 67 has a circular hole shape. A first end of the second axial path 67 communicates with a second end of the first axial path 66 . The axis of the second axial path 67 coincides with the axis of the first axial path 66.

The third axial path 68 extends inside the second axial member 45 in the axial direction of the second axial member 45 . The third axial path 68 has a circular hole shape. A first end of the third axial path 68 communicates with a second end of the second axial path 67. The axis of the third axial path 68 coincides with the axis of the second axial path 67. The second end of the third shaft path 68 is located inside the second shaft member 45 . The second end of the third axial passage 68 is closed inside the second axial member 45 .

In this way, the axial path 65 passes through the first axial member 44 and the permanent magnet 42 and reaches the inside of the second axial member 45 . The shaft path 65 extends inside the first shaft member 44 , the permanent magnet 42 , and the second shaft member 45 in the axial direction of the rotating shaft 40 . Therefore, the axial path 65 extends inside the rotating shaft 40 in the axial direction of the rotating shaft 40. The shaft passage 65 opens at one end of the first shaft member 44 on the impeller 49 side and communicates with the suction port 22 .

<Route 69>
The rotor 33 includes a plurality of paths 69. The plurality of paths 69 communicate with the second end of the third axial path 68 . Therefore, each path 69 communicates with the axial path 65. As shown in FIG. 5, each path 69 extends from the third axial path 68 toward the opposing surface 60a of the protrusion 60. Each path 69 extends obliquely to the axis of the rotating shaft 40 . Each path 69 extends toward the opposing surface 60a of the protrusion 60 while gradually moving away from the permanent magnet 42 as it moves away from the third axial path 68. Each path 69 passes through the protrusion 60 and opens to the opposing surface 60a of the protrusion 60. Therefore, each path 69 passes through the protrusion 60 and opens at a portion of the protrusion 60 that faces the second coil end 36b. A portion of each path 69 is formed in the protrusion 60 . The plurality of paths 69 extend radially from the third axial path 68. A first end of each path 69 communicates with the third axial path 68 . The second end of each path 69 opens to the opposing surface 60a of the protrusion 60 and communicates with the inside of the motor chamber 18. Therefore, each path 69 extends from the shaft path 65 in the radial direction of the rotating shaft 40 and communicates with the inside of the motor chamber 18 . Each path 69 causes the air sucked into the shaft path 65 from the suction port 22 to flow toward the second coil end 36b.

As shown in FIG. 1, air from the suction port 22 is introduced into the first end of the first shaft path 66. The air introduced into the first axial path 66 from the suction port 22 is introduced into the motor chamber 18 via the first axial path 66, the second axial path 67, the third axial path 68, and each path 69. .

<Discharge port 80>
As shown in FIG. 2, the housing 11 has a discharge port 80. The discharge port 80 is formed in the first plate 15. The discharge port 80 is arranged closer to the impeller chamber 23 than the motor chamber 18 . The discharge port 80 extends inside the first plate 15 in the radial direction of the rotating shaft 40 . A first end of the discharge port 80 is open to the outer peripheral surface of the first plate 15 . A second end of the discharge port 80 communicates with the thrust bearing housing chamber 19 . The discharge port 80 discharges the air introduced into the motor chamber 18 from the suction port 22 via the shaft path 65 and each path 69 to the outside of the housing 11 .

<Cooling passage 81>
As shown in FIGS. 5 and 6, a cooling passage 81 is formed in the second radial bearing holding portion 26. As shown in FIGS. As shown in FIG. 6 , a plurality of cooling passages 81 are formed at intervals in the circumferential direction of the second radial bearing holding portion 26 . Therefore, a plurality of cooling passages 81 are formed in the second radial bearing holding part 26 at intervals in the circumferential direction of the second radial bearing holding part 26 . Each cooling passage 81 has, for example, a circular hole shape.

As shown in FIG. 3, each cooling passage 81 penetrates the second radial bearing holding portion 26 in the axial direction of the rotating shaft 40 and extends to the inside of the second plate 16. A first end of each cooling passage 81 opens at the tip end surface of the second radial bearing holding portion 26 . The second end of each cooling passage 81 is located inside the second plate 16. Air introduced into the motor chamber 18 from each path 69 flows into each cooling passage 81 .

<Discharge passage 82>
As shown in FIG. 1, the housing 11 has a discharge passage 82. The exhaust passage 82 passes through the second plate 16 and the motor housing 12. The discharge passage 82 connects the shaft insertion hole 16h and the discharge port 80. A first end of the discharge passage 82 communicates with the shaft insertion hole 16h. A second end of the discharge passage 82 communicates with the discharge port 80.

<Annular passage 83>
Housing 11 has an annular passage 83. An annular passage 83 is formed inside the second plate 16 . The annular passage 83 surrounds the shaft insertion hole 16h and extends in the circumferential direction of the rotating shaft 40 around the shaft insertion hole 16h. An annular passage 83 traverses the discharge passage 82 . The annular passage 83 communicates with the discharge passage 82 . The second end of each cooling passage 81 is connected to the annular passage 83 . Therefore, the second end of each cooling passage 81 communicates with the annular passage 83.

[Operation of embodiment]
Next, the operation of this embodiment will be explained.
A portion of the air from the suction port 22 is introduced into the axial path 65 and flows through the axial path 65 and each path 69. The air flowing through each path 69 is accelerated by the centrifugal force accompanying the rotation of the rotating shaft 40 and is introduced into the motor chamber 18 from each path 69 . The permanent magnet 42 is cooled by air flowing through the axial path 65. Therefore, the permanent magnet 42 is cooled by air that is lower temperature than the compressed air.

Since a part of each path 69 through which the air sucked into the shaft path 65 from the suction port 22 flows toward the second coil end 36b is formed in the protruding portion 60, the air is introduced into the motor chamber 18 from each path 69. This makes it easier for the air to flow toward the second coil end 36b. Therefore, the second coil end 36b is easily cooled by the air introduced into the motor chamber 18. As a result, the coil 35 is efficiently cooled.

Further, a portion of the air introduced into the motor chamber 18 from each path 69 passes through the space 71 between the stator 32 and the rotor 33 and flows inside the first radial bearing holding portion 21 . The first radial bearing 51 is cooled by air flowing inside the first radial bearing holding section 21 . The air that has passed through the first radial bearing holding portion 21 flows into the thrust bearing housing chamber 19 . The thrust bearing 53 is cooled by air passing through the thrust bearing housing chamber 19 . The air in the thrust bearing housing chamber 19 is then discharged to the outside of the housing 11 through the discharge port 80.

On the other hand, a portion of the air introduced into the motor chamber 18 from each path 69 flows into each cooling passage 81 . Heat exchange occurs between the air flowing through each cooling passage 81 and the second radial bearing 52 via the second radial bearing holding portion 26, so that the second radial bearing 52 is cooled by the air. The air that has passed through each cooling passage 81 is discharged to the outside of the housing 11 from the discharge port 80 via the annular passage 83 and the discharge passage 82 . Note that a portion of the air introduced into the motor chamber 18 from each path 69 flows inside the second radial bearing holding portion 26 . The second radial bearing 52 is also cooled by air passing inside the second radial bearing holding section 26 . The air that has passed through the inside of the second radial bearing holding portion 26 is discharged to the outside of the housing 11 from the discharge port 80 via the shaft insertion hole 16h and the discharge passage 82.

[Effects of embodiment]
In the above embodiment, the following effects can be obtained.
(1) A portion of each path 69 is formed in the protruding portion 60, through which the air sucked into the shaft path 65 from the suction port 22 flows toward the second coil end 36b. Therefore, the air introduced into the motor chamber 18 from each path 69 tends to flow toward the second coil end 36b. Therefore, the second coil end 36b is easily cooled by the air introduced into the motor chamber 18. As a result, the coil 35 can be efficiently cooled.

(2) Each path 69 penetrates the protrusion 60 and opens to the opposing surface 60a of the protrusion 60. According to this, each path 69 penetrates the protrusion 60 and opens to the opposing surface 60a facing the second coil end 36b of the protrusion 60, so that the passage 69 is introduced into the motor chamber 18 from each path 69. This makes it easier for the air to flow toward the second coil end 36b. Therefore, the second coil end 36b is easily cooled by the air introduced into the motor chamber 18. As a result, the coil 35 can be efficiently cooled.

(3) The opposing surface 60a of the protruding portion 60 is located between the second coil end 36b and the outer circumferential surface of the second radial bearing holding portion 26 when viewed from the axial direction of the rotating shaft 40. According to this, for example, when the opposing surface 60a of the protrusion 60 overlaps the second radial bearing holding part 26 in the axial direction of the rotating shaft 40 when viewed from the axial direction of the rotating shaft 40. Compared to this, the facing surface 60a can be brought as close as possible to the second coil end 36b. Therefore, since the air introduced into the motor chamber 18 from each path 69 flows more easily toward the second coil end 36b, the second coil end 36b is further cooled by the air introduced into the motor chamber 18. It becomes easier. As a result, the coil 35 can be cooled more efficiently.

(4) The opposing surface 60a of the protrusion 60 overlaps the end surface of the stator core 34 in the axial direction of the rotating shaft 40 when viewed from the axial direction of the rotating shaft 40. According to this, for example, compared to a case where the opposing surface 60a of the protruding portion 60 is located radially inward than the inner circumferential surface of the stator core 34 when viewed from the axial direction of the rotating shaft 40, the protruding portion 60 is The facing surface 60a of the portion 60 can be brought as close as possible to the second coil end 36b. Therefore, since the air introduced into the motor chamber 18 from each path 69 flows more easily toward the second coil end 36b, the second coil end 36b is further cooled by the air introduced into the motor chamber 18. It becomes easier. As a result, the coil 35 can be cooled more efficiently.

(5) A recess 61 is formed in the protrusion 60 to adjust the rotational balance of the rotating shaft 40. The protrusion 60 protruding from the outer circumferential surface of the rotation shaft 40 is suitable as a portion for forming the recess 61 in order to adjust the rotational balance of the rotation shaft 40.

(6) The axial path 65 passes through the first axial member 44 and the permanent magnet 42 and reaches the inside of the second axial member 45 . The protruding portion 60 protrudes from the outer peripheral surface of the second shaft member 45 toward the second coil end 36b. According to this, the permanent magnet 42 can be cooled by the air flowing through the axial path 65. Therefore, in addition to the coil 35, the permanent magnet 42 can also be efficiently cooled by air, so that the durability of the motor 31 can be improved.

(7) The second radial bearing holding portion 26 is formed with a cooling passage 81 into which air introduced into the motor chamber 18 from each path 69 flows. According to this, heat exchange is performed between the air flowing through the cooling passage 81 and the second radial bearing 52 via the second radial bearing holding part 26, so that the second radial bearing 52 can be cooled by the air. . Furthermore, as much as the air flows through the cooling passage 81, it becomes difficult for the air to pass through the inside of the second radial bearing holding part 26, so that foreign matter is prevented from entering the inside of the second radial bearing holding part 26 together with the air. suppressed. Therefore, the problem that the second radial bearing 52 is worn out by foreign matter can be easily avoided, so that the durability of the second radial bearing 52 can be improved.

(8) A plurality of cooling passages 81 are formed in the second radial bearing holding part 26 at intervals in the circumferential direction of the second radial bearing holding part 26 . According to this, for example, compared to the case where only one cooling passage 81 is formed in the second radial bearing holding part 26, the entire second radial bearing 52 is uniformly distributed in the circumferential direction of the second radial bearing holding part 26. can be easily cooled. Therefore, the second radial bearing 52 can be efficiently cooled.

[Example of change]
Note that the above embodiment can be modified and implemented as follows. The above embodiment and the following modification examples can be implemented in combination with each other within a technically consistent range.

In the embodiment, the protrusion 60 may protrude toward the first coil end 36a from a portion of the outer peripheral surface of the first shaft member 44 that faces the first coil end 36a. In this case, a portion of each path 69 through which air sucked into the shaft path 65 from the suction port 22 flows toward the first coil end 36a is formed in the protrusion 60. According to this, the air introduced into the motor chamber 18 from each path 69 becomes easier to flow toward the first coil end 36a. Therefore, the first coil end 36a is easily cooled by the air introduced into the motor chamber 18. As a result, the coil 35 is efficiently cooled. Note that in this case, the shaft path 65 does not need to extend in the axial direction of the rotating shaft 40 through the first shaft member 44 and the permanent magnet 42 to reach the inside of the second shaft member 45 .

In the embodiment, each path 69 does not need to extend obliquely to the axis of the rotating shaft 40. Each path 69 may extend in a direction perpendicular to the axial direction of the rotating shaft 40. In short, each path 69 only needs to extend from the axis path 65 in the radial direction of the rotating shaft 40 and communicate with the inside of the motor chamber 18 .

In the embodiment, the opposing surface 60a of the protrusion 60 is not located between the second coil end 36b and the outer circumferential surface of the second radial bearing holding portion 26 when viewed from the axial direction of the rotating shaft 40. It's okay. For example, the opposing surface 60a of the protruding portion 60 may overlap the distal end surface of the second radial bearing holding portion 26 in the axial direction of the rotating shaft 40 when viewed from the axial direction of the rotating shaft 40.

In the embodiment, the second radial bearing holding portion 26 does not need to enter inside the second coil end 36b. Even in this case, the outer peripheral surface of the second radial bearing holding portion 26 may be located inside the second coil end 36b when viewed from the axial direction of the rotating shaft 40. The opposing surface 60a of the protruding portion 60 may be located between the second coil end 36b and the outer circumferential surface of the second radial bearing holding portion 26 when viewed from the axial direction of the rotating shaft 40.

In the embodiment, the opposing surface 60a of the protrusion 60 does not need to overlap the end surface of the stator core 34 in the axial direction of the rotating shaft 40 when viewed from the axial direction of the rotating shaft 40. In short, the opposing surface 60a of the protrusion 60 may be located radially inward than the inner circumferential surface of the stator core 34 when viewed from the axial direction of the rotating shaft 40.

In the embodiment, the concave portion 61 for adjusting the rotational balance of the rotating shaft 40 may not be formed in the protruding portion 60.
In the embodiment, for example, only one cooling passage 81 may be formed in the second radial bearing holding portion 26.

In the embodiment, the shape of each cooling passage 81 is not particularly limited.
In the embodiment, the cooling passage 81 may not be formed in the second radial bearing holding portion 26.

In the embodiment, a plurality of cooling passages 81 may be formed in the first radial bearing holding portion 21.
In the embodiment, the protrusion 60 does not have to be annular, and may be, for example, a columnar protrusion that protrudes from the outer peripheral surface of the second shaft member 45 at intervals in the circumferential direction of the second shaft member 45. Good too. Further, as the protruding portion 60, only one column-shaped protrusion may protrude from the outer circumferential surface of the second shaft member 45. In short, the protruding portion 60 only needs to protrude toward the coil end 36 from a portion of the outer circumferential surface of the rotating shaft 40 that faces the coil end 36 .

In the embodiment, each path 69 may be open, for example, at an end surface of the protrusion 60 located in the thickness direction. In short, it is sufficient that the protrusion 60 has a part of the path 69 through which the air sucked into the shaft path 65 from the suction port 22 flows toward the coil end 36, and the opening position of the path 69 relative to the protrusion 60 is fixed. is not particularly limited.

In the embodiment, the number of paths 69 is not particularly limited.
In the embodiment, the permanent magnet 42 may not be press-fitted into the inner circumferential surface of the cylindrical member 41, but may be adhered to the inner circumferential surface of the cylindrical member 41 with, for example, an adhesive. In short, the permanent magnet 42 only needs to be fixed inside the cylindrical member 41.

In the embodiment, the centrifugal compressor 10 may be configured without the turbine wheel 50.
In the embodiment, the centrifugal compressor 10 may be configured to include an impeller instead of the turbine wheel 50. That is, the centrifugal compressor 10 has an impeller attached to each of the first shaft member 44 and the second shaft member 45, and the air compressed by one impeller is compressed again by the other impeller. There may be.

In the embodiment, the magnetic material is not limited to the permanent magnet 42, and may be, for example, a laminated core, an amorphous core, a dust core, or the like.
(circle) In embodiment, the cylinder member 41 may be comprised from carbon fiber reinforced plastic, for example. In short, the material of the cylindrical member 41 is not particularly limited.

○ In the embodiment, the centrifugal compressor 10 does not need to be mounted on the fuel cell vehicle. In short, the centrifugal compressor 10 is not limited to one that is mounted on a vehicle.
[Additional notes]
The above embodiment includes the configuration described in the following supplementary notes.

<Additional note 1>
a rotating shaft;
a motor that rotates the rotating shaft;
an impeller that compresses air by rotating integrally with the rotating shaft;
An impeller chamber for accommodating the impeller, a motor chamber for accommodating the motor, and a housing having an inlet for sucking air into the impeller chamber,
The motor is
a stator core fixed to the housing; a stator having a coil end that is part of a coil wound around the stator core and protrudes from an end surface of the stator core;
a rotor disposed inside the stator and rotating integrally with the rotating shaft,
an axial path that opens toward the suction port and extends inside the rotating shaft in the axial direction of the rotating shaft;
A centrifugal compressor comprising a path that communicates with the axial path, extends from the axial path in a radial direction of the rotating shaft, and communicates with the motor chamber,
The rotating shaft has a protrusion that projects toward the coil end from a portion of the outer circumferential surface of the rotating shaft that faces the coil end,
A centrifugal compressor characterized in that a part of the path through which air sucked into the axial path from the suction port flows toward the coil end is formed in the protrusion.

<Additional note 2>
The protrusion has a facing surface facing the coil end,
The centrifugal compressor according to Supplementary Note 1, wherein the path passes through the protrusion and opens to the opposing surface.

<Additional note 3>
a radial bearing rotatably supporting the rotating shaft with respect to the housing;
The housing has a cylindrical radial bearing holding part that holds the radial bearing,
The outer circumferential surface of the radial bearing holding portion is located inside the coil end when viewed from the axial direction of the rotating shaft,
The centrifugal device according to <Appendix 2>, wherein the opposing surface is located between the coil end and the outer circumferential surface of the radial bearing holding part when viewed from the axial direction of the rotating shaft. compressor.

<Additional note 4>
According to <Appendix 2> or <Appendix 3>, wherein the opposing surface overlaps the end face of the stator core in the axial direction of the rotating shaft, when viewed from the axial direction of the rotating shaft. Centrifugal compressor as described.

<Additional note 5>
The centrifugal compressor according to any one of <Appendix 1> to <Appendix 4>, wherein the protruding portion is formed with a recess for adjusting the rotational balance of the rotating shaft.

<Additional note 6>
The rotor is
A cylindrical member,
a magnetic body fixed inside the cylindrical member,
The rotation axis is
including a first shaft member and a second shaft member provided on both sides of the magnetic body in the axial direction of the cylindrical member,
The impeller is connected to the first shaft member,
The axial path passes through the first axial member and the magnetic body and reaches the inside of the second axial member,
The centrifugal compressor according to any one of <Appendix 1> to <Appendix 5>, wherein the protruding portion protrudes from the outer peripheral surface of the second shaft member toward the coil end.

<Additional note 7>
a radial bearing rotatably supporting the rotating shaft with respect to the housing;
The housing has a cylindrical radial bearing holding part that holds the radial bearing,
According to any one of <Appendix 1> to <Appendix 6>, wherein the radial bearing holding part is formed with a cooling passage through which air introduced into the motor chamber from the path flows. centrifugal compressor.

<Additional note 8>
The centrifugal compressor according to Supplementary Note 7, wherein the radial bearing holder includes a plurality of cooling passages spaced apart from each other in the circumferential direction of the radial bearing holder.

DESCRIPTION OF SYMBOLS 10... Centrifugal compressor, 11... Housing, 18... Motor chamber, 21... First radial bearing holding part which is a radial bearing holding part, 22... Suction port, 23... Impeller chamber, 26... Second radial bearing holding part which is Radial bearing holding part, 31... Motor, 32... Stator, 33... Rotor, 34... Stator core, 35... Coil, 36... Coil end, 40... Rotating shaft, 41... Cylindrical member, 42... Permanent magnet which is a magnetic material, 44 ...First shaft member, 45... Second shaft member, 49... Impeller, 51... First radial bearing which is a radial bearing, 52... Second radial bearing which is a radial bearing, 60... Projection, 60a... Opposing surface, 61 ... recess, 65 ... shaft path, 69 ... path, 81 ... cooling passage.

Claims (8)

a rotating shaft;
a motor that rotates the rotating shaft;
an impeller that compresses air by rotating integrally with the rotating shaft;
An impeller chamber for accommodating the impeller, a motor chamber for accommodating the motor, and a housing having an inlet for sucking air into the impeller chamber,
The motor is
a stator core fixed to the housing; a stator having a coil end that is part of a coil wound around the stator core and protrudes from an end surface of the stator core;
a rotor disposed inside the stator and rotating integrally with the rotating shaft,
an axial path that opens toward the suction port and extends inside the rotating shaft in the axial direction of the rotating shaft;
A centrifugal compressor comprising a path that communicates with the axial path, extends from the axial path in a radial direction of the rotating shaft, and communicates with the motor chamber,
The rotating shaft has a protrusion that projects toward the coil end from a portion of the outer circumferential surface of the rotating shaft that faces the coil end,
A centrifugal compressor characterized in that a part of the path through which air sucked into the axial path from the suction port flows toward the coil end is formed in the protrusion. The protrusion has a facing surface facing the coil end,
The centrifugal compressor according to claim 1, wherein the path passes through the protrusion and opens to the opposing surface. a radial bearing rotatably supporting the rotating shaft with respect to the housing;
The housing has a cylindrical radial bearing holding part that holds the radial bearing,
The outer circumferential surface of the radial bearing holding portion is located inside the coil end when viewed from the axial direction of the rotating shaft,
The centrifugal compressor according to claim 2, wherein the opposing surface is located between the coil end and an outer circumferential surface of the radial bearing holding part when viewed from the axial direction of the rotating shaft. Machine. 4. The opposing surface overlaps the end surface of the stator core in the axial direction of the rotating shaft when viewed from the axial direction of the rotating shaft. Centrifugal compressor. The centrifugal compressor according to claim 1, wherein the protrusion has a recess formed therein to adjust the rotational balance of the rotating shaft. The rotor is
A cylindrical member,
a magnetic body fixed inside the cylindrical member,
The rotation axis is
including a first shaft member and a second shaft member provided on both sides of the magnetic body in the axial direction of the cylindrical member,
The impeller is connected to the first shaft member,
The axial path passes through the first axial member and the magnetic body and reaches the inside of the second axial member,
The centrifugal compressor according to claim 1, wherein the protrusion protrudes from an outer peripheral surface of the second shaft member toward the coil end. a radial bearing rotatably supporting the rotating shaft with respect to the housing;
The housing has a cylindrical radial bearing holding part that holds the radial bearing,
The centrifugal compressor according to claim 1, wherein the radial bearing holding portion is formed with a cooling passage into which air introduced into the motor chamber from the path flows. The centrifugal compressor according to claim 7, wherein a plurality of the cooling passages are formed in the radial bearing holder at intervals in a circumferential direction of the radial bearing holder.

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