Centrifugal Compressor

Abstract

To increase the ability to cool a thrust bearing.SOLUTION: A seal plate 17 has therein a cooling gas passage G1. Air cools a first thrust bearing 60 and a second thrust bearing 61, and further cools the seal plate 17 while flowing through the cooling gas passage G1. The seal plate 17 further has therein a cooling water passage W1. The cooling water flowing through the cooling water passage W1 cools the seal plate 17. That is, the heat of the air compressed by a compressor impeller 34 is less likely to transfer, via the seal plate 17, to the first thrust bearing 60 and the second thrust bearing 61 accommodated in a thrust bearing accommodation chamber S2. Accordingly, the first thrust bearing 60 and the second thrust bearing 61 are efficiently cooled by the air. Further, the heat of the first thrust bearing 60 and the second thrust bearing 61 is released to the cooling water flowing through the cooling water passage W1.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] An example of a centrifugal compressor is described in Patent Document 1. The centrifugal compressor includes a rotating shaft and a compressor impeller. The compressor impeller is attached to the rotating shaft. The compressor impeller rotates integrally with the rotating shaft. The compressor impeller compresses a fluid. The rotating shaft and the compressor impeller are housed in a housing of the centrifugal compressor. The centrifugal compressor also includes a thrust bearing. The thrust bearing supports the rotating shaft so that it can rotate in the thrust direction.

[0003] The housing has an impeller chamber and a thrust bearing accommodating chamber. The impeller chamber accommodates a compressor impeller. The thrust bearing accommodating chamber accommodates a thrust bearing. The housing also has a partition wall that separates the impeller chamber and the thrust bearing accommodating chamber. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-127898 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the temperature of the fluid compressed by the compressor impeller becomes higher than before it was compressed. If the heat of the compressed fluid is transmitted through the partition to the thrust bearing housed in the thrust bearing housing, the temperature of the thrust bearing increases, and the durability of the thrust bearing deteriorates. Therefore, there is a demand for improving the cooling performance of the thrust bearing. [Means for solving the problem]

[0006] A centrifugal compressor that solves the above problem includes a rotating shaft, a compressor impeller that is attached to the rotating shaft and rotates integrally with the rotating shaft to compress a fluid, a housing that accommodates the rotating shaft and the compressor impeller, and a thrust bearing that supports the rotating shaft rotatably in a thrust direction, wherein the housing has an impeller chamber in which the compressor impeller is accommodated, a thrust bearing accommodating chamber in which the thrust bearing is accommodated, and a partition wall that separates the impeller chamber and the thrust bearing accommodating chamber, and the partition wall has, inside the partition wall, a cooling gas passage through which a cooling gas flows for cooling the thrust bearing, and a cooling water passage through which cooling water flows for cooling the partition wall.

[0007] According to this, the partition has a cooling gas passage therein. Therefore, the cooling gas can cool the partition by flowing through the cooling gas passage while cooling the thrust bearing. Furthermore, since the partition has a cooling water passage therein, the partition can be further cooled by the cooling water. Therefore, the heat of the fluid compressed by the compressor impeller is less likely to be transmitted to the thrust bearing accommodated in the thrust bearing accommodating chamber via the partition. Therefore, the thrust bearing can be efficiently cooled by the cooling gas. Furthermore, the heat of the thrust bearing is dissipated to the cooling water flowing through the cooling water passage. Therefore, the cooling performance for the thrust bearing can be improved.

[0008] In the centrifugal compressor, the cooling water passage may be located radially outward of the rotating shaft relative to the cooling gas passage. This allows the surface area of ​​the cooling water passage to be increased compared to when the cooling water passage is located radially inward of the rotating shaft relative to the cooling gas passage. Therefore, the partition wall can be cooled efficiently. This makes it even more difficult for heat from the fluid compressed by the compressor impeller to be transmitted through the partition wall to the thrust bearing accommodated in the thrust bearing accommodation chamber. Furthermore, heat from the thrust bearing is even more easily dissipated to the cooling water flowing through the cooling water passage. As a result, the cooling performance of the thrust bearing can be further improved. Effect of the Invention

[0009] According to the present invention, the cooling performance for the thrust bearing can be improved. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side cross-sectional view showing a centrifugal compressor according to an embodiment. [Diagram 2] FIG. 2 is an enlarged side cross-sectional view showing a portion of the centrifugal compressor. [Diagram 3] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a centrifugal compressor according to one embodiment will be described with reference to Figures 1 to 3. The centrifugal compressor of this embodiment is mounted on a fuel cell vehicle. <Overall Configuration of Centrifugal Compressor 10> 1, the centrifugal compressor 10 includes a housing 11. The housing 11 is made of a metal material, for example, aluminum. 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.

[0012] The motor housing 12 is cylindrical. The motor housing 12 has a plate-shaped end wall 12a and a peripheral wall 12b. The peripheral wall 12b extends cylindrically from the outer periphery of the end wall 12a. The first plate 15 is connected to an end of the peripheral wall 12b of the motor housing 12 on the opening side. The first plate 15 closes the opening of the peripheral wall 12b of the motor housing 12. The end wall 12a and the peripheral wall 12b of the motor housing 12 and the first plate 15 define a motor chamber S1. The motor chamber S1 accommodates the electric motor 40.

[0013] As shown in FIG. 2, a first recess 15c and a second recess 15d are formed on an end surface 15a of the first plate 15 opposite to the motor housing 12. The first recess 15c and the second recess 15d are circular holes. The inner diameter of the first recess 15c is larger than the inner diameter of the second recess 15d. The axis of the first recess 15c and the axis of the second recess 15d are aligned. The inner peripheral surface 15e of the first recess 15c connects the end surface 15a and the bottom surface 15f of the first recess 15c. The inner peripheral surface 15g of the second recess 15d connects the bottom surface 15f of the first recess 15c and the bottom surface 15h of the second recess 15d.

[0014] The first plate 15 has a first bearing retaining portion 20. The first bearing retaining portion 20 is cylindrical. The first bearing retaining portion 20 protrudes from the center of the end face 15b of the first plate 15 toward the electric motor 40. The first bearing retaining portion 20 penetrates the first plate 15 and opens at the bottom face 15h of the second recess 15d. The axis of the first bearing retaining portion 20 coincides with the axis of the first recess 15c and the second recess 15d.

[0015] As shown in Fig. 1, the motor housing 12 has a second bearing retaining portion 21. The second bearing retaining portion 21 is cylindrical. The second bearing retaining portion 21 protrudes from the center of an inner surface 121a of an end wall 12a of the motor housing 12 toward the electric motor 40. The inner side of the second bearing retaining portion 21 penetrates the end wall 12a of the motor housing 12 and opens to an outer surface 122a of the end wall 12a. The axis of the first bearing retaining portion 20 and the axis of the second bearing retaining portion 21 coincide with each other.

[0016] The second plate 16 is connected to an outer surface 122a of the end wall 12a of the motor housing 12. A shaft insertion hole 16a is formed in the center of the second plate 16. The shaft insertion hole 16a communicates with the inside of the second bearing holder 21. The axis of the shaft insertion hole 16a coincides with the axis of the second bearing holder 21.

[0017] As shown in FIG. 2, a shaft insertion hole 17a is formed in the center of the seal plate 17. The axis of the shaft insertion hole 17a coincides with the axis of the first bearing holder 20. The seal plate 17 has a plurality of bolt insertion holes 17h through which the bolt B1 can be inserted. The plurality of bolt insertion holes 17h are arranged at intervals around the shaft insertion hole 17a on the outer periphery of the seal plate 17. Note that FIG. 2 illustrates one of the plurality of bolt insertion holes 17h. Each bolt insertion hole 17h is a circular hole. The seal plate 17 is attached to the first plate 15 by screwing the bolts B1 inserted into the bolt insertion holes 17h into the first plate 15 in a state where the seal plate 17 is fitted into the first recess 15c. The seal plate 17 closes the opening of the second recess 15d. An end face 17b of the seal plate 17 close to the first plate 15 and the second recess 15d of the first plate 15 define a thrust bearing accommodating chamber S2.

[0018] The compressor housing 13 is cylindrical. The compressor housing 13 has a circular suction port 13a. The compressor housing 13 is connected to an end face 15a of the first plate 15 in a state in which the axis of the suction port 13a coincides with the axis of the shaft insertion hole 17a of the seal plate 17 and the axis of the first bearing holder 20. The suction port 13a opens in the end face of the compressor housing 13 opposite to the first plate 15.

[0019] Between the compressor housing 13 and the seal plate 17, there are formed an impeller chamber 13b, a discharge chamber 13c, and a first diffuser passage 13d. Therefore, the seal plate 17 functions as a partition wall separating the impeller chamber 13b from the thrust bearing accommodating chamber S2. The impeller chamber 13b communicates with the suction port 13a. The discharge chamber 13c extends around the axis of the suction port 13a around the periphery of the impeller chamber 13b. The first diffuser passage 13d communicates with the impeller chamber 13b and the discharge chamber 13c. The impeller chamber 13b communicates with a shaft insertion hole 17a of the seal plate 17.

[0020] As shown in Fig. 1, the turbine housing 14 is cylindrical. The turbine housing 14 has a circular discharge port 14a. The turbine housing 14 is connected to an end face 16b of the second plate 16 opposite the motor housing 12 with the axis of the discharge port 14a coinciding with the axis of the shaft insertion hole 16a of the second plate 16 and the axis of the second bearing holder 21. The discharge port 14a opens into the end face of the turbine housing 14 opposite the second plate 16.

[0021] A turbine chamber 14b, a suction chamber 14c, and a second diffuser passage 14d are formed between the turbine housing 14 and an end face 16b of the second plate 16. The turbine chamber 14b communicates with the discharge port 14a. The suction chamber 14c extends around the axis of the discharge port 14a around the turbine chamber 14b. The second diffuser passage 14d communicates with the turbine chamber 14b and the suction chamber 14c. The turbine chamber 14b communicates with the shaft insertion hole 16a.

[0022] <Configuration of Rotating Body A1> The centrifugal compressor 10 includes a rotating body A1. The rotating body A1 includes a rotating shaft 30, a first support portion 31, a second support portion 32, and a support plate 33. Thus, the centrifugal compressor 10 includes the rotating shaft 30. The rotating shaft 30, the first support portion 31, the second support portion 32, and the support plate 33 are accommodated in a housing 11.

[0023] The rotating shaft 30 is accommodated in the housing 11 with the axial direction of the rotating shaft 30 coinciding with the axial direction of the motor housing 12. A first end 30a of the rotating shaft 30 protrudes from the motor chamber S1 into the impeller chamber 13b, passing through the inside of the first bearing holder 20, the thrust bearing accommodating chamber S2, and the shaft insertion hole 17a. A second end 30b of the rotating shaft 30 protrudes from the motor chamber S1 into the turbine chamber 14b, passing through the inside of the second bearing holder 21 and the shaft insertion hole 16a.

[0024] A first seal member 22 is provided between the shaft insertion hole 17a of the seal plate 17 and the rotating shaft 30. The first seal member 22 suppresses air leakage from the impeller chamber 13b toward the motor chamber S1. A second seal member 23 is provided between the shaft insertion hole 16a of the second plate 16 and the rotating shaft 30. The second seal member 23 suppresses air leakage from the turbine chamber 14b toward the motor chamber S1. The first seal member 22 and the second seal member 23 are, for example, seal rings.

[0025] The first support portion 31 is provided on an outer circumferential surface 300 of the rotating shaft 30 at a portion closer to the first end portion 30a. The first support portion 31 is disposed inside the first bearing holder 20. The first support portion 31 is formed integrally with the rotating shaft 30. The first support portion 31 protrudes from the outer circumferential surface 300 of the rotating shaft 30.

[0026] The second support part 32 is provided on an outer circumferential surface 300 of the rotating shaft 30 near the second end 30b. The second support part 32 is disposed inside the second bearing holder 21. The second support part 32 is fixed to the outer circumferential surface 300 of the rotating shaft 30 in a state in which the second support part 32 protrudes in an annular shape from the outer circumferential surface 300 of the rotating shaft 30. The second support part 32 is rotatable integrally with the rotating shaft 30.

[0027] The support plate 33 is accommodated in the thrust bearing accommodating chamber S2. The support plate 33 is fixed to the outer circumferential surface 300 of the rotating shaft 30 in a state in which the support plate 33 protrudes annularly radially outward from the outer circumferential surface 300 of the rotating shaft 30. Therefore, the support plate 33 is separate from the rotating shaft 30. The support plate 33 can rotate integrally with the rotating shaft 30.

[0028] <About Compressor Impeller 34> The centrifugal compressor 10 includes a compressor impeller 34. The compressor impeller 34 is attached to a first end 30a in the axial direction of the rotating shaft 30. The compressor impeller 34 is disposed closer to the first end 30a than the support plate 33 of the rotating shaft 30. The compressor impeller 34 is accommodated in the impeller chamber 13b. Thus, the housing 11 has the impeller chamber 13b in which the compressor impeller 34 is accommodated. Thus, the housing 11 accommodates the rotating shaft 30 and the compressor impeller 34. Thus, the centrifugal compressor 10 includes the housing 11 that accommodates the rotating shaft 30 and the compressor impeller 34. The compressor impeller 34 rotates integrally with the rotating shaft 30.

[0029] <About Turbine Wheel 35> The centrifugal compressor 10 includes a turbine wheel 35. The turbine wheel 35 is attached to the second end 30b of the rotating shaft 30. The turbine wheel 35 is disposed closer to the second end 30b than the second support portion 32 of the rotating shaft 30. The turbine wheel 35 is accommodated in the turbine chamber 14b. The turbine wheel 35 rotates integrally with the rotating shaft 30.

[0030] <Configuration of Electric Motor 40> The electric motor 40 includes a cylindrical rotor 41 and a cylindrical stator 42. The rotor 41 is fixed to the rotating shaft 30. The stator 42 is fixed to the housing 11. The rotor 41 is disposed radially inside the stator 42 and rotates integrally with the rotating shaft 30. The rotor 41 includes a cylindrical rotor core 41a fixed to the rotating shaft 30 and a plurality of permanent magnets (not shown) provided on the rotor core 41a. The stator 42 surrounds the rotor 41. The stator 42 includes a cylindrical stator core 43 fixed to the inner circumferential surface 121b of the peripheral wall 12b of the motor housing 12 and a coil 44 wound around the stator core 43. The rotating shaft 30 rotates integrally with the rotor 41 when a current flows from a battery (not shown) to the coil 44. Thus, the electric motor 40 rotates the rotating shaft 30. The electric motor 40 is disposed between the compressor impeller 34 and the turbine wheel 35 in the axial direction of the rotating shaft 30 .

[0031] <Regarding the first radial bearing 50 and the second radial bearing 51> The centrifugal compressor 10 includes a first radial bearing 50 and a second radial bearing 51. The first radial bearing 50 is cylindrical. The first radial bearing 50 is held by the first bearing holder 20. The second radial bearing 51 is cylindrical. The second radial bearing 51 is held by the second bearing holder 21. The first radial bearing 50 and the second radial bearing 51 support the rotating shaft 30 rotatably relative to the housing 11 in the radial direction. The "radial direction" refers to a direction perpendicular to the axial direction of the rotating shaft 30.

[0032] <Regarding the first thrust bearing 60 and the second thrust bearing 61> 2, the centrifugal compressor 10 includes a first thrust bearing 60 and a second thrust bearing 61 serving as thrust bearings. The first thrust bearing 60 and the second thrust bearing 61 support the support plate 33 rotatably relative to the housing 11 in a thrust direction. The "thrust direction" is a direction parallel to the axial direction of the rotating shaft 30.

[0033] The first thrust bearing 60 and the second thrust bearing 61 are accommodated in the thrust bearing accommodating chamber S2. Therefore, the housing 11 has the thrust bearing accommodating chamber S2 in which the first thrust bearing 60 and the second thrust bearing 61 are accommodated. The first thrust bearing 60 and the second thrust bearing 61 are arranged to sandwich the support plate 33. The first thrust bearing 60 is arranged on the compressor impeller 34 side with respect to the support plate 33. The second thrust bearing 61 is arranged on the opposite side of the support plate 33 to the compressor impeller 34. The first thrust bearing 60 has a first thrust bearing main body portion 60a and a first base portion 60b. The first base portion 60b is disk-shaped. A first through hole 60c through which the rotating shaft 30 passes is formed in the first base portion 60b. The second thrust bearing 61 has a second thrust bearing main body portion 61a and a second base portion 61b. The second base portion 61b is disk-shaped and has a second through-hole 61c through which the rotation shaft 30 passes.

[0034] <About Fuel Cell System 1> As shown in FIG. 1, the centrifugal compressor 10 configured as above constitutes a part of a fuel cell system 1 mounted on a fuel cell vehicle. In addition to the centrifugal compressor 10, the fuel cell system 1 includes a fuel cell stack 100, a supply flow path L1, a discharge flow path L2, and a branch flow path L3. The fuel cell stack 100 is composed of a plurality of battery cells. For convenience of explanation, the illustration of each battery cell is omitted. The supply flow path L1 connects the discharge chamber 13c and the fuel cell stack 100. The discharge flow path L2 connects the fuel cell stack 100 and the suction chamber 14c.

[0035] When the rotating shaft 30 rotates integrally with the rotor 41, the compressor impeller 34 and the turbine wheel 35 rotate integrally with the rotating shaft 30. Then, air taken in from the suction port 13a is compressed by the compressor impeller 34 in the impeller chamber 13b, passes through the first diffuser passage 13d, and is discharged from the discharge chamber 13c. Therefore, the compressor impeller 34 rotates integrally with the rotating shaft 30 to compress the air.

[0036] The air discharged from the discharge chamber 13c is supplied to the fuel cell stack 100 through the supply passage L1. The air supplied to the fuel cell stack 100 is used to generate power in the fuel cell stack 100. The air passing through the fuel cell stack 100 is then discharged to the discharge passage L2 as exhaust air from the fuel cell stack 100. The exhaust air from the fuel cell stack 100 is drawn into the suction chamber 14c through the discharge passage L2. The exhaust air from the fuel cell stack 100 drawn into the suction chamber 14c is introduced into the turbine chamber 14b through the second diffuser passage 14d. The turbine wheel 35 is rotated by the exhaust air from the fuel cell stack 100 introduced into the turbine chamber 14b. The rotating shaft 30 is rotated by the rotation of the turbine wheel 35, which is rotated by the exhaust air from the fuel cell stack 100, in addition to the rotation caused by the drive of the electric motor 40. The rotation of the rotating shaft 30 is assisted by the rotation of the turbine wheel 35 caused by the exhaust air from the fuel cell stack 100. The exhaust gas that has passed through the turbine chamber 14b is discharged to the outside from the discharge port 14a.

[0037] <About the cooling gas passage G1 and the air flowing through it> As shown in Figures 2 and 3, a recess 17c is formed in the center of the end surface 17b of the seal plate 17. The recess 17c is a circular hole. Most of the opening of the recess 17c is closed by the second base portion 61b. A cooling gas passage G1 is defined by the recess 17c of the seal plate 17 and the second base portion 61b. The cooling gas passage G1 and the thrust bearing accommodating chamber S2 communicate with each other through the second through hole 61c of the second base portion 61b and the rotating shaft 30.

[0038] The seal plate 17 is formed with a communication hole 17e and a connection passage G2. The communication hole 17e is a circular hole. The communication hole 17e opens to an end face 17b of the seal plate 17. The connection passage G2 connects the recess 17c and the communication hole 17e. The connection passage G2 extends from the cooling gas passage G1 toward the outside in the radial direction of the rotating shaft 30.

[0039] Further, a through hole 15i is formed in the first plate 15. The through hole 15i penetrates the first plate 15 in the thickness direction. The axis of the communication hole 17e and the axis of the through hole 15i coincide with each other. One end of the through hole 15i communicates with the communication hole 17e. The other end of the through hole 15i communicates with the motor chamber S1. Therefore, the communication hole 17e communicates with the motor chamber S1 via the through hole 15i. In this way, the cooling gas passage G1 communicates with the motor chamber S1 via the connection passage G2, the communication hole 17e, and the through hole 15i.

[0040] In the cooling gas passage G1, a cooling gas for cooling the first thrust bearing 60 and the second thrust bearing 61 flows. Specifically, a first passage 71 is formed in the first plate 15. The first passage 71 extends in the radial direction of the rotating shaft 30. One end of the first passage 71 opens to the outer surface of the first plate 15. The other end of the first passage 71 communicates with the thrust bearing accommodating chamber S2. In addition, a second passage 72 is formed in the second plate 16. The second passage 72 extends in the radial direction of the rotating shaft 30. One end of the second passage 72 opens to the outer surface of the second plate 16. The other end of the second passage 72 communicates with a portion of the shaft insertion hole 16a closer to the motor housing 12 than the second seal member 23.

[0041] Further, the branch passage L3 branches off from the supply passage L1. The branch passage L3 connects the supply passage L1 and the first passage 71. An intercooler R1 is provided in the middle of the branch passage L3. The intercooler R1 cools the air flowing through the branch passage L3.

[0042] A portion of the air compressed by the compressor impeller 34 and flowing through the supply passage L1 toward the fuel cell stack 100 flows into the first passage 71 via the branch passage L3. The air flowing into the first passage 71 is cooled by the intercooler R1 while flowing through the branch passage L3. The air that flows into the first passage 71 flows into the thrust bearing accommodation chamber S2 and cools the first thrust bearing 60 and the second thrust bearing 61. Therefore, the cooling gas for cooling the first thrust bearing 60 and the second thrust bearing 61 is a portion of the air compressed by the compressor impeller 34.

[0043] Then, the air in the thrust bearing accommodating chamber S2 flows into the cooling gas passage G1 through a gap between the second through hole 61c of the second base portion 61b and the rotating shaft 30. The air that has flowed into the cooling gas passage G1 passes through the connecting passage G2 and flows into the motor chamber S1 via the communication hole 17e and the through hole 15i.

[0044] The electric motor 40 is cooled by the air that flows into the motor chamber S1. A part of the air that flows into the motor chamber S1 flows between the first radial bearing 50 and the first support portion 31 and cools the first radial bearing 50. The air that flows into the motor chamber S1 passes between the rotor 41 and the stator 42, for example, and flows between the second radial bearing 51 and the second support portion 32 and cools the second radial bearing 51. The air that passes between the second radial bearing 51 and the second support portion 32 is then discharged to the outside of the housing 11 via the shaft insertion hole 16a and the second flow path 72.

[0045] <About the cooling water passage W1> A groove 17d is formed on the end face 17b of the seal plate 17. The groove 17d extends in the circumferential direction of the rotating shaft 30 so as to surround the recess 17c on the end face 17b of the seal plate 17 at a radially outer side of the rotating shaft 30 than the recess 17c. The groove 17d meanders around the axis of the shaft insertion hole 17a. Specifically, the groove 17d is formed so that a portion extending so as to approach the axis of the shaft insertion hole 17a and a portion extending so as to move away from the axis of the shaft insertion hole 17a are alternately formed in succession. The groove 17d extends in the circumferential direction of the rotating shaft 30 so as to pass through the radially inner side of the rotating shaft 30 with respect to each bolt insertion hole 17h. A first end 170d of the groove 17d and a second end 171d of the groove 17d are arranged so that the groove 17d extends over almost the entire circumferential area of ​​the seal plate 17. The opening of the groove 17d is closed by the first plate 15. The groove 17d and a bottom surface 15f of the first recess 15c of the first plate 15 define a cooling water passage W1. Therefore, the cooling water passage W1 is located radially outward of the rotating shaft 30 relative to the cooling gas passage G1. A seal member (not shown) is provided between the end surface 17b of the seal plate 17 and the bottom surface 15f of the first recess 15c of the first plate 15 to prevent leakage of the cooling water flowing through the cooling water passage W1.

[0046] 1, the centrifugal compressor 10 includes a cooling water jacket 12c. The cooling water jacket 12c is formed on a peripheral wall 12b of the motor housing 12. The cooling water jacket 12c extends over the entire circumferential circumference of the peripheral wall 12b.

[0047] 2, a first end of the cooling water passage W1 is connected to the cooling water jacket 12c via a connecting cooling water passage W2, and a second end of the cooling water passage W1 is connected to the cooling water jacket 12c via a connecting cooling water passage W3.

[0048] The cooling water jacket 12c is connected to a first end and a second end of an external flow passage (not shown). Cooling water (LLC) flows through the external flow passage. A radiator (not shown) is also provided in the external flow passage. The cooling water flowing through the external flow passage is cooled by heat exchange with outside air when passing through the radiator. Therefore, the cooling water circulates by flowing through the external flow passage, the cooling water jacket 12c, the connecting cooling water passage W2, the cooling water passage W1, the connecting cooling water passage W3, and the cooling water jacket 12c in this order. Therefore, the cooling water flows through the cooling water passage W1. The cooling water flowing through the cooling water passage W1 cools the seal plate 17. Therefore, the seal plate 17 has, inside the seal plate 17, a cooling gas passage G1 through which a cooling gas flows for cooling the first thrust bearing 60 and the second thrust bearing 61, and a cooling water passage W1 through which cooling water flows for cooling the seal plate 17.

[0049] <effect> Next, the operation of this embodiment will be described. The seal plate 17 has a cooling gas passage G1 inside the seal plate 17. The air cools the first thrust bearing 60 and the second thrust bearing 61 while also cooling the seal plate 17 by flowing through the cooling gas passage G1. Furthermore, the seal plate 17 has a cooling water passage W1 inside the seal plate 17. The cooling water flowing through the cooling water passage W1 cools the seal plate 17. Therefore, the heat of the air compressed by the compressor impeller 34 is not easily transmitted to the first thrust bearing 60 and the second thrust bearing 61 accommodated in the thrust bearing accommodation chamber S2 through the seal plate 17. Therefore, the first thrust bearing 60 and the second thrust bearing 61 are efficiently cooled by the air. Furthermore, the heat of the first thrust bearing 60 and the second thrust bearing 61 is dissipated to the cooling water flowing through the cooling water passage W1.

[0050] <Effects> The above embodiment can provide the following effects. (1) The seal plate 17 has a cooling gas passage G1 inside the seal plate 17. Therefore, the air can cool the seal plate 17 by flowing through the cooling gas passage G1 while cooling the first thrust bearing 60 and the second thrust bearing 61. Furthermore, since the seal plate 17 has a cooling water passage W1 inside the seal plate 17, the seal plate 17 can be further cooled by the cooling water. Therefore, the heat of the air compressed by the compressor impeller 34 is not easily transmitted to the first thrust bearing 60 and the second thrust bearing 61 accommodated in the thrust bearing accommodation chamber S2 through the seal plate 17. Therefore, the first thrust bearing 60 and the second thrust bearing 61 can be efficiently cooled by the air. Furthermore, the heat of the first thrust bearing 60 and the second thrust bearing 61 is dissipated to the cooling water flowing through the cooling water passage W1. Therefore, the cooling performance for the first thrust bearing 60 and the second thrust bearing 61 can be improved.

[0051] (2) The cooling water passage W1 is located radially outward of the rotating shaft 30 relative to the cooling gas passage G1. This allows the surface area of ​​the cooling water passage W1 to be increased compared to a case in which the cooling water passage W1 is located radially inward of the rotating shaft 30 relative to the cooling gas passage G1. Therefore, the seal plate 17 can be cooled efficiently. Therefore, the heat of the fluid compressed by the compressor impeller 34 is further less likely to be transmitted through the seal plate 17 to the first thrust bearing 60 and the second thrust bearing 61 accommodated in the thrust bearing accommodation chamber S2. Furthermore, the heat of the first thrust bearing 60 and the second thrust bearing 61 is further easily dissipated to the cooling water flowing through the cooling water passage W1. As a result, the cooling performance of the first thrust bearing 60 and the second thrust bearing 61 can be further improved.

[0052] <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.

[0053] In the above embodiment, the cooling water passage W1 may be disposed radially inward of the cooling gas passage G1. In the above embodiment, the groove 17d does not have to be meandering. In other words, the shape of the groove 17d is not particularly limited.

[0054] In the above embodiment, the cooling water flowing through the cooling water passage W1 may be different from the cooling water flowing through the cooling water jacket 12c. In other words, there is no particular limitation on the way the cooling water flows through the cooling water passage W1.

[0055] In the above embodiment, the air that has cooled the first thrust bearing 60 and the second thrust bearing 61 in the thrust bearing accommodation chamber S2 flows into the cooling gas passage G1, but this is not limited to the above. For example, the air that has flowed through the cooling gas passage G1 may flow into the thrust bearing accommodation chamber S2 to cool the first thrust bearing 60 and the second thrust bearing 61.

[0056] In the embodiment, a portion of the air compressed by the compressor impeller 34 flows into the cooling gas passage G1 as the cooling gas flowing through the cooling gas passage G1, but this is not limited to the above, and the cooling gas may be air other than the air compressed by the compressor impeller 34.

[0057] In the above-mentioned embodiment, the centrifugal compressor 10 may not include the turbine wheel 35. In the embodiment, the centrifugal compressor 10 may be configured to include a compressor impeller instead of the turbine wheel 35. In other words, the centrifugal compressor 10 may be configured such that compressor impellers are attached to both ends of the rotating shaft 30, and the fluid compressed by one compressor impeller is compressed again by the other compressor impeller.

[0058] In the above-described embodiment, the centrifugal compressor 10 may be driven by an engine, for example. In the embodiment, the centrifugal compressor 10 does not have to be mounted on a fuel cell vehicle, and may be used in, for example, a vehicle air conditioner to compress a refrigerant as a fluid. Furthermore, the centrifugal compressor 10 is not limited to being mounted on a vehicle. [Explanation of symbols]

[0059] 10... centrifugal compressor, 11... housing, 13b... impeller chamber, 17... seal plate serving as partition, 30... rotating shaft, 34... compressor impeller, 60... first thrust bearing serving as thrust bearing, 61... second thrust bearing serving as thrust bearing, G1... cooling gas passage, S2... thrust bearing accommodating chamber, W1... cooling water passage.

Claims

1. A rotation axis; A compressor impeller that is attached to the rotating shaft and rotates integrally with the rotating shaft to compress a fluid; a housing that accommodates the rotating shaft and the compressor impeller; a thrust bearing that rotatably supports the rotating shaft in a thrust direction, The housing includes: an impeller chamber in which the compressor impeller is accommodated; a thrust bearing accommodating chamber in which the thrust bearing is accommodated; a partition wall separating the impeller chamber and the thrust bearing accommodating chamber, The partition wall is a cooling gas passage through which a cooling gas for cooling the thrust bearing flows and a cooling water passage through which cooling water for cooling the partition wall flows are provided inside the partition wall, The cooling gas passage and the cooling water passage are formed in an axial end surface of the partition wall on the side of the thrust bearing housing.

2. The centrifugal compressor according to claim 1 , wherein the cooling water passage is located radially outward of the rotating shaft relative to the cooling gas passage.

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