TURBO FLUID MACHINE

A turbo fluid machine includes: a housing; an electric motor; an impeller that compresses fluid; and a drive shaft connecting the impeller and the electric motor in the housing. The impeller chamber includes a first impeller chamber and a second impeller chamber distanced from each other in an axial direction of the drive shaft. The impeller includes: a first impeller that compresses the fluid to produce first compressed fluid; and a second impeller that compresses the first compressed fluid to produce second compressed fluid. The turbo fluid machine further includes: a compressed fluid passage through which the first compressed fluid is supplied to the second impeller chamber; and a plurality of flow straightening passages that extends inside the compressed fluid passage in a direction in which the compressed fluid passage extends, and through which the first compressed fluid is straightened and supplied to the second impeller chamber.

Skip to: Description  ·  Claims  · Patent History  ·  Patent History
Description
CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2022-022811 filed on Feb. 17, 2022, the entire disclosure of which is incorporated herein by reference.

BACKGROUND ART

The present disclosure relates to a turbo fluid machine.

Japanese Patent Application Publication No. 2015-187444 and Japanese Patent Application Publication No. H08-200296 disclose a conventional turbo fluid machine. The turbo fluid machine of Japanese Patent Application Publication No. 2015-187444 includes a housing, an electric motor, an impeller, a drive shaft, and a compressed fluid passage. The housing includes an impeller chamber and a motor chamber. The impeller chamber includes a first impeller chamber and a second impeller chamber distanced from the first impeller chamber in an axial direction of the drive shaft. The motor chamber is disposed between the first impeller chamber and the second impeller chamber. The electric motor is accommodated in the motor chamber.

The impeller includes a first impeller accommodated in the first impeller chamber and a second impeller accommodated in the second impeller chamber. The drive shaft is accommodated in the housing and extends in the axial direction of the drive shaft to connect the first and second impellers and the electric motor. The housing has an outlet and an inlet. The outlet communicates with the first impeller chamber, and the inlet communicates with the second impeller chamber. The compressed fluid passage is disposed outside the housing and connects the outlet and the inlet.

In such a turbo fluid machine, the first and second impellers rotate with rotation of the electric motor to compress fluid in two steps. Specifically, the first impeller compresses the fluid inside the first impeller chamber to produce first compressed fluid. The first compressed fluid is supplied from the first impeller chamber to the second impeller chamber through the compressed fluid passage. Then, the second impeller compresses the first compressed fluid to produce second compressed fluid.

In the above-described turbo fluid machine, when the first impeller and the to second impeller rotate, a rotational component is applied to the first compressed fluid and the second compressed fluid. Then, in such a turbo fluid machine, the first compressed fluid having the rotational component is supplied to the second impeller chamber through the compressed fluid passage. Thus, when the second impeller compresses the first compressed fluid to produce the second compressed fluid, it is difficult to increase a pressure of the second compressed fluid due to the rotational component included in the first compressed fluid. This causes a decrease in compression performance of the fluid.

On the other hand, in the turbo fluid machine of Japanese Patent Application Publication No. H08-200296, a division plate is provided inside a compressed fluid passage. The division plate has, in its central portion, an opening into which first compressed fluid flows. The division plate has an annular shape. The division plate includes a plurality of return guide vanes. The return guide vanes are arranged in a circumferential direction of the division plate.

In such a turbo fluid machine, the first compressed fluid flowing through the compressed fluid passage is guided from an outer circumferential side of the division plate into the opening by the return guide vanes and flows from the opening toward an inlet. Thus, in this turbo fluid machine, the first compressed fluid is straightened by the return guide vanes of the division plate and supplied to the second impeller chamber. As a result, in this turbo fluid machine, a pressure of the second compressed fluid increases sufficiently.

This kind of turbo fluid machine needs to be downsized in order that the turbo fluid machine is easily mounted on a vehicle or the like. However, in the turbo fluid machine of Japanese Patent Application Publication No. H08-200296, downsizing of the division plate is difficult due to a complicated configuration of the division plate, and it is necessary to increase in size to secure a space for the division plate. Thus, the downsizing of this kind of turbo fluid machine is difficult. In addition, a manufacturing cost of the turbo fluid machine increases due to the complicated configuration of the division plate.

The present disclosure, which has been made in light of the above-mentioned problem, is directed to providing a turbo fluid machine reducing a size and a manufacturing cost thereof with a high compression performance.

SUMMARY

In accordance with an aspect of the present disclosure, there is provided a turbo fluid machine that includes: a housing including an impeller chamber and a motor chamber; an electric motor accommodated in the motor chamber; an impeller that is accommodated in the impeller chamber and compresses fluid with rotation of the electric motor; and a drive shaft connecting the impeller and the electric motor in the housing. The impeller chamber includes a first impeller chamber and a second impeller chamber distanced from each other in an axial direction of the drive shaft. The impeller includes: a first impeller that is accommodated in the first impeller chamber and compresses the fluid to produce first compressed fluid; and a second impeller that is accommodated in the second impeller chamber and compresses the first compressed fluid to produce second compressed fluid. The turbo fluid machine further includes: a compressed fluid passage through which the first compressed fluid is supplied to the second impeller chamber; and a plurality of flow straightening passages that extends inside the compressed fluid passage in a direction in which the compressed fluid passage extends, and through which the first compressed fluid is straightened and supplied to the second impeller chamber.

Other aspects and advantages of the disclosure will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure, together with objects and advantages thereof, may best be understood by reference to the following description of the embodiments together with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a turbo fluid machine according to a first embodiment;

FIG. 2 is an enlarged cross-sectional view of a main part of the turbo fluid machine according to the first embodiment, illustrating “X” of FIG. 1;

FIG. 3 is a cross-sectional view of the turbo fluid machine according to the first embodiment, taken along a line III-III of FIG. 2;

FIG. 4A is a schematic view of a cross-sectional area of a compressed fluid passage in the turbo fluid machine according to the first embodiment, and FIG. 4B is a schematic view of a cross-sectional area of a flow straightening passage in the turbo fluid machine according to the first embodiment;

FIG. 5 is an enlarged cross-sectional view of a main part of a turbo fluid machine according to a second embodiment, illustrating a compressed fluid passage, a flow straightening passage, and a cooling portion, as with FIG. 2;

FIG. 6 is a cross-sectional view of the turbo fluid machine according to the second embodiment, taken along a line VI-VI of FIG. 5;

FIG. 7A is a schematic view of a cross-sectional area of a compressed fluid passage in the turbo fluid machine according to the second embodiment, and FIG. 7B is a schematic view of a cross-sectional area of a flow straightening passage in the turbo fluid machine according to the second embodiment;

FIG. 8 is a cross-sectional view of the turbo fluid machine according to the second embodiment, taken along a line VIII-VIII of FIG. 5;

FIG. 9 is a cross-sectional view of a turbo fluid machine according to a third embodiment, as seen in the same direction as that of FIG. 3; and

FIG. 10A is a schematic view of a cross-sectional area of a compressed fluid passage in the turbo fluid machine according to the third embodiment, and FIG. 10B is a schematic view of a cross-sectional area of a flow straightening passage in the turbo fluid machine according to the third embodiment.

 DETAILED DESCRIPTION OF THE EMBODIMENTS

The following will describe first to third embodiments of the present disclosure with reference to drawings. A turbo fluid machine of each of the first to third embodiments is mounted on a fuel cell vehicle, and connected to a fuel cell stack. The fuel cell vehicle and the fuel cell stack are not illustrated.

As illustrated in FIGS. 1 to 3, the turbo fluid machine of the first embodiment includes a housing 1, an electric motor 3, a drive shaft 5, an impeller including a first impeller 7 and a second impeller 8, a compressed fluid passage 9, and seven first flow straightening passages 31a to 31g. Each of the first flow straightening passages 31a to 31g is an example of a “flow straightening passage” of the present disclosure.

In the present embodiment, a solid arrow of FIG. 1 indicates a front-rear direction of the turbo fluid machine. The front-rear direction corresponds to an example of an “axial direction of a drive shaft” of the present disclosure. Terms of “front/rear” and “forward/rearward” indicate the front-rear direction of the turbo fluid machine. An orientation of the turbo fluid machine is appropriately changeable depending on a vehicle on which the turbo fluid machine is mounted.

The housing 1 is made of aluminum alloy. As illustrated in FIG. 1, the housing 1 includes a motor housing 10, a first plate 11, a second plate 12, a third plate 13, a first compressor housing 14, and a second compressor housing 15.

The motor housing 10 has an end wall 10a and a peripheral wall 10b. The end wall 10a is disposed at a rear end of the motor housing 10 and extends in a radial direction of the motor housing 10. The end wall 10a has a first end surface 101 facing to the front and a second end surface 102 that is opposite to the first end surface 101 and faces to the rear. The second end surface 102 forms a rear end surface of the motor housing 10.

The peripheral wall 10b is formed integrally with the end wall 10a and extends tubularly forward from the end wall 10a. The peripheral wall 10b has, in its front part, an opening. The end wall 10a and the peripheral wall 10b define the motor housing 10 with a bottomed tubular shape. A flange portion 10c is formed at a front end of the peripheral wall 10b. The flange portion 10c protrudes outward from the peripheral wall 10b in the radial direction of the motor housing 10.

The first plate 11 is disposed in front of the motor housing 10. The first plate 11 includes a first front surface 11a positioned at the front and a first rear surface 11b positioned at the rear. The first plate 11 allows the first rear surface 11b to be in contact with the flange portion 10c and is connected to the flange portion 10c. As a result, the first plate 11 closes the opening of the peripheral wall 10b. Thus, the end wall 10a, the peripheral wall 10b, and the first rear surface 11b define a motor chamber 30 inside the motor housing 10.

The first plate 11 includes a first boss portion 11c, a first recess 11d, and a first shaft hole 11e. The first boss portion 11c protrudes cylindrically rearward from the first rear surface 11b, and extends inside the motor chamber 30. A first radial bearing 21a is provided inside the first boss portion 11c.

The first front surface 11a is recessed rearward to form the first recess 11d. A first thrust bearing 23a and a second thrust bearing 23b are provided inside the first recess 11d. The first shaft hole 11e is positioned in a central portion of the first plate 11 and extends through the first plate 11 in the front-rear direction. Thus, the first shaft hole 11e communicates with the first recess 11d at a front end of the first shaft hole 11e, and communicates with the first boss portion 11c at a rear end of the first shaft hole 11e. The first boss portion 11c, the first recess 11d, and the first shaft hole 11e are formed coaxially with each other.

The end wall 10a of the motor housing 10 includes a second boss portion 10d and a second shaft hole 10e. The second boss portion 10d protrudes cylindrically forward from the first end surface 101 and extends inside the motor chamber 30. A second radial bearing 21b is provided inside the second boss portion 10d. The second shaft hole 10e is disposed in a central portion of the end wall 10a and extends through the end wall 10a in the front-rear direction. Thus, the second shaft hole 10e communicates with the second boss portion 10d at a front end of the second shaft hole 10e. The second boss portion 10d and the second shaft hole 10e are formed coaxially with the first boss portion 11c, the first recess 11d, and the first shaft hole 11e.

The second plate 12 is disposed in front of the first plate 11. The second plate 12 includes a second front surface 12a on a front side of the second plate 12 and a second rear surface 12b on a rear side of the second plate 12. The second plate 12 allows the second rear surface 12b to be in contact with the first front surface 11a and is connected to the first plate 11.

The second plate 12 includes a second recess 12c and a third shaft hole 12d. The second front surface 12a is recessed rearward to form the second recess 12c. The second recess 12c has a diameter smaller than that of the first recess 11d. A first sealing member 25a is provided inside the second recess 12c. The third shaft hole 12d is disposed in a central portion of the second plate 12 and extends through the second plate 12 in the front-rear direction. Thus, the third shaft hole 12d communicates with the second recess 12c at a front end of the third shaft hole 12d, and communicates with the first recess 11d at a rear end of the third shaft hole 12d. The second recess 12c and the third shaft hole 12d are formed coaxially with the first boss portion 11c, the first recess 11d, and the first shaft hole 11e.

The third plate 13 is disposed in the rear of the motor housing 10. The third plate 13 includes a third front surface 13a on a front side of the third plate 13 and a third rear surface 13b on a rear side of the third plate 13. The third plate 13 allows the third front surface 13a to be in contact with the second end surface 102 of the end wall 10a and is connected to the motor housing 10.

The third plate 13 includes a third recess 13c and a fourth shaft hole 13d. The third rear surface 13b is recessed forward to form the third recess 13c. The third recess 13c has the same diameter as that of the second recess 12c. A second sealing member 25b is provided inside the third recess 13c. The fourth shaft hole 13d is disposed in a central portion of the third plate 13 and extends through the third plate 13 in the front-rear direction. Thus, the fourth shaft hole 13d communicates with the second shaft hole 10e at a front end of the fourth shaft hole 13d and communicates with the third recess 13c at a rear end of the fourth shaft hole 13d. The third recess 13c and the fourth shaft hole 13d are formed coaxially with the second boss portion 10d and the second shaft hole 10e. That is, the third recess 13c and the fourth shaft hole 13d are formed coaxially with the first boss portion 11c, the first recess 11d, the first shaft hole 11e, the second recess 12c, and the third shaft hole 12d.

The first compressor housing 14 is disposed in front of the second plate 12. The first compressor housing 14 has a tubular shape. The first compressor housing 14 is in contact with the second front surface 12a of the second plate 12 and connected to the second plate 12. As a result, the first compressor housing 14 forms a front end portion of the housing 1. The first compressor housing 14 has a first inlet 14a and a first outlet 14b.

The first inlet 14a is formed coaxially with the third shaft hole 12d and extends inside the first compressor housing 14 in the front-rear direction. A front to end of the first inlet 14a is opened at a front end surface 140 of the first compressor housing 14. An inlet piping 37 is connected to the first inlet 14a. Air containing oxygen is drawn into the first inlet 14a from an outside of the housing 1 through the inlet piping 37. The air is an example of “fluid” of the present disclosure.

The first outlet 14b extends inside the first compressor housing 14 in its radial direction and is opened at an outer peripheral surface 141 of the first compressor housing 14. A first straight passage 9a of the compressed fluid passage 9 which will be described later is connected to the first outlet 14b.

A first impeller chamber 27a, a first discharge chamber 27b, and a first diffuser passage 27c are formed between the first compressor housing 14 and the second front surface 12a. The first impeller chamber 27a communicates with the first inlet 14a. The first discharge chamber 27b is formed around the first impeller chamber 27a and extends around an axis of the first inlet 14a. The first discharge chamber 27b communicates with the first outlet 14b. The first impeller chamber 27a communicates with the first discharge chamber 27b through the first diffuser passage 27c. As a result, the first impeller chamber 27a communicates with the first outlet 14b through the first diffuser passage 27c and the first discharge chamber 27b.

The second compressor housing 15 is disposed in the rear of the third plate 13. The second compressor housing 15 has a tubular shape, as with the first compressor housing 14. The second compressor housing 15 is in contact with the third rear surface 13b of the third plate 13 and connected to the third plate 13. Thus, the second compressor housing 15 forms a rear end portion of the housing 1. The second compressor housing 15 has a second inlet 15a and a second outlet 15b.

The second inlet 15a is formed coaxially with the first inlet 14a and extends inside the second compressor housing 15 in the front-rear direction. A rear end of the second inlet 15a is opened at a rear end surface 150 of the second compressor housing 15. A fourth straight passage 9d of the compressed fluid passage 9 which will be described later is connected to the second inlet 15a.

The second outlet 15b extends inside the second compressor housing 15 in its radial direction, and is opened at the outer peripheral surface 151 of the second compressor housing 15. A discharge piping 39 is connected to the second outlet 15b. Through the discharge piping 39, the turbo fluid machine is connected to the fuel cell stack.

A second impeller chamber 29a, a second discharge chamber 29b, and a second diffuser passage 29c are formed between the second compressor housing and the third rear surface 13b. The second impeller chamber 29a communicates with the second inlet 15a. The second discharge chamber 29b is formed around the second impeller chamber 29a and extends around an axis of the second inlet 15a. The second discharge chamber 29b communicates with the second outlet 15b. The second impeller chamber 29a communicates with the second discharge chamber 29b through the second diffuser passage 29c. As a result, the second impeller chamber 29a communicates with the second outlet 15b through the second diffuser passage 29c and the second discharge chamber 29b.

As described above, in the housing 1, the first impeller chamber 27a and the second impeller chamber 29a are distanced from each other in the front-rear direction, and the motor chamber 30 is disposed between the first impeller chamber 27a and the second impeller chamber 29a. The first impeller chamber 27a and the second impeller chamber 29a are collectively referred to as an impeller chamber.

The electric motor 3 is accommodated in the motor chamber 30. The electric motor 3 includes a stator 3a and a rotor 3b. The stator 3a has a cylindrical shape, extends in the front-rear direction, and is fixed to an inner peripheral surface of the peripheral wall 10b. The stator 3a is connected to a power supplier (not illustrated) provided outside the housing 1. The rotor 3b whose diameter is smaller than that of the stator 3a has a cylindrical shape and extends in the front-rear direction. The rotor 3b is disposed inside the stator 3a.

The drive shaft 5 has a cylindrical columnar shape and extends in the axial direction of the drive shaft 5, i.e., in the front-rear direction. The drive shaft 5 has a first shaft portion 5a, a second shaft portion 5b, a third shaft portion 5c, a fourth shaft portion 5d, and a fifth shaft portion 5e arranged in this order from the front to the rear. The first shaft portion 5a and the fifth shaft portion 5e have the same diameter and each have the smallest diameter in the drive shaft 5. The second shaft portion 5b and the fourth shaft portion 5d have the same diameter and each have a diameter larger than that of each of the first shaft portion 5a and the fifth shaft portion 5e. A front end of the second shaft portion 5b is connected to the first shaft portion 5a. A rear end of the fourth shaft portion 5d is connected to the fifth shaft portion 5e. The third shaft portion 5c has the largest diameter in the drive shaft 5. A front end of the third shaft portion 5c is connected to the second shaft portion 5b, and a rear end of the third shaft portion 5c is connected to the fourth shaft portion 5d.

The drive shaft 5 is inserted into the housing 1, and is rotatable around a shaft axis O. In the drive shaft 5, the first shaft portion 5a extends inside the first impeller chamber 27a. The shaft axis O extends in a direction parallel to the front-rear direction of the turbo fluid machine.

The second shaft portion 5b is inserted into the third shaft hole 12d and the first shaft hole 11e, and extends inside the second recess 12c and the first recess 11d. The second shaft portion 5b is inserted into the first sealing member 25a inside the second recess 12c. As a result, the first sealing member 25a seals a gap between the first impeller chamber 27a and, the first recess 11d and the motor chamber 30. The second shaft portion 5b is inserted into the first thrust bearing 23a and the second thrust bearing 23b inside the first recess 11d, and is press-fitted into a support plate 51. The support plate 51 is disposed between the first thrust bearing 23a and the second thrust bearing 23b. Thus, the support plate 51 holds the first thrust bearing 23a between the second rear surface 12b and the support plate 51 in the front-rear direction, and holds the second thrust bearing 23b between a wall surface of the first recess 11d and the support plate 51 in the front-rear direction.

The third shaft portion 5c extends inside the motor chamber 30. The third shaft portion 5c is inserted into and fixed to the rotor 3b. The third shaft portion 5c is supported by the first radial bearing 21a inside the first boss portion 11c, and supported by the second radial bearing 21b inside the second boss portion 10d.

The fourth shaft portion 5d is inserted into the fourth shaft hole 13d and extends inside the third recess 13c. The fourth shaft portion 5d is inserted into the second sealing member 25b inside the third recess 13c. As a result, the second sealing member 25b seals a gap between the second impeller chamber 29a and the motor chamber 30. The fifth shaft portion 5e extends inside the second impeller chamber 29a.

The first impeller 7 is accommodated in the first impeller chamber 27a. The first impeller 7 is formed into a substantially conical shape whose diameter gradually increases from the front to the rear. On the other hand, the second impeller 8 is accommodated in the second impeller chamber 29a. The second impeller 8 is symmetrical to the first impeller 7 in the front-rear direction. That is, the second impeller 8 is formed into a substantially conical shape whose diameter gradually decreases from the front to the rear. The first impeller 7 is made of aluminum alloy, and the second impeller 8 is made of steel.

The first impeller 7 is fixed to the first shaft portion 5a of the drive shaft 5. The second impeller 8 is fixed to the fifth shaft portion 5e of the drive shaft 5. Thus, the drive shaft 5 connects the first and second impellers 7, 8 and the electric motor 3.

The compressed fluid passage 9 is provided separately from the housing 1 and disposed outside the housing 1. The compressed fluid passage 9 includes a first straight passage 9a, a second straight passage 9b, a third straight passage 9c, a fourth straight passage 9d, a first corner passage 9e, a second corner passage 9f, and a third corner passage 9g. The compressed fluid passage 9 including the first to fourth straight passages 9a to 9d and the first to third corner passages 9e to 9g is formed of a metal piping having a cylindrical shape. First compressed air which will be described later flows through the compressed fluid passage 9.

The first to fourth straight passages 9a to 9d extend straight in their longitudinal directions. The first compressed air flows through the first to fourth straight passages 9a to 9d in their longitudinal directions. As illustrated in FIG. 2 and FIG. 3, an inner diameter of the third straight passage 9c corresponds to a first length L1. An inner diameter of each of the first, second, and fourth straight passages 9a, 9b, 9d of FIG. 1 also corresponds to the first length L1. The first to third corner passages 9e to 9g are each bent at a substantially right angle. An inner diameter of each of the first to third corner passages 9e to 9g is larger than that of each of the first to fourth straight passages 9a to 9d. The first to fourth straight passages 9a to 9d extend inside the first to third corner passages 9e to 9g.

In the compressed fluid passage 9, the first straight passage 9a, the first corner passage 9e, the second straight passage 9b, the second corner passage 9f, the third straight passage 9c, the third corner passage 9g, and the fourth straight passage 9d are arranged in this order in a flowing direction of the first compressed air which will be described later. Then, in the compressed fluid passage 9, one end of the first straight passage 9a is connected to the first outlet 14b. Through the first corner passage 9e, the other end of the first straight passage 9a is connected to one end of the second straight passage 9b. Through the second corner passage 9f, the other end of the second straight passage 9b is connected to one end of the third straight passage 9c. Through the third corner passage 9g, the other end of the third straight passage 9c is connected to one end of the fourth straight passage 9d. The other end of the fourth straight passage 9d is connected to the second inlet 15a. The compressed fluid passage 9 connects the first outlet 14b and the second inlet 15a as described above. The first to fourth straight passages 9a to 9d each form a straight portion of the compressed fluid passage 9, and the first to third corner passages 9e to 9g each form a corner portion of the compressed fluid passage 9.

Here, in the compressed fluid passage 9, a distance from the third straight passage 9c to the second inlet 15a is smaller than that from the first outlet 14b to the third straight passage 9c. That is, in the compressed fluid passage 9, the third straight passage 9c is disposed at a position closer to the second inlet 15a than to the first outlet 14b, i.e., at a position closer to the second impeller chamber 29a than to the first impeller chamber 27a. The compressed fluid passage 9 may have any shape as appropriate.

As illustrated in FIG. 1 to FIG. 3, the first flow straightening passages 31a to 31g are provided inside the third straight passage 9c. As a result, in the compressed fluid passage 9, the first flow straightening passages 31a to 31g are each disposed at a position closer to the second impeller chamber 29a than to the first impeller chamber 27a.

As illustrated in FIG. 2 and FIG. 3, the first flow straightening passages 31a to 31g have the same configuration, and are each formed of a cylindrical body that is made of metal and extends straight in a direction parallel to the longitudinal direction of the third straight passage 9c. Specifically, the first flow straightening passages 31a to 31g are each formed of a known pipe made of metal. Thus, the first compressed airflows through the first flow straightening passages 31a to 31g. A length of each of the first flow straightening passages 31a to 31g in a longitudinal direction thereof is smaller than that of the third straight passage 9c in the longitudinal direction thereof. Any number of the first flow straightening passages 31a to 31g may be provided appropriately as long as a plurality of first flow straightening passages is provided. The first flow straightening passages 31a to 31g may be formed of a cylindrical body made of resin.

An inner diameter of each of the first flow straightening passages 31a to 31g corresponds to a second length L2. The second length L2 is smaller than the first length L1 corresponding to the inner diameter of the compressed fluid passage 9. Specifically, the second length L2 is smaller than one-third of the first length L1. Thus, as illustrated in FIG. 4B, a second passage cross-sectional area S2 that is a cross-sectional area of each of the first flow straightening passages 31a to 31g is smaller than a first passage cross-sectional area S1 that is a cross-sectional area of the third straight passage 9c of FIG. 4A. Furthermore, a sum of seven second passage cross-sectional areas S2 corresponding to the number of the first flow straightening passages 31a to 31g is smaller than the first passage cross-sectional area S1.

As illustrated in FIG. 3, the first flow straightening passages 31a to 31g are bonded to each other while the first flow straightening passage 31a is disposed in a central portion of the compressed fluid passage 9 and bonded to the first flow straightening passages 31b to 31g arranged in a circumferential direction of the first flow straightening passage 31a. The first flow straightening passages 31a to 31g are inserted into the third straight passage 9c and are bonded and fixed to an inner peripheral surface 901 of the third straight passage 9c. As a result, the first flow straightening passages 31a to 31g are provided inside the third straight passage 9c.

In the above-described turbo fluid machine, the power supplier supplies power to the electric motor 3 illustrated in FIG. 1 to operate the electric motor 3, which causes the drive shaft 5 to rotate around the shaft axis O. With rotation of the electric motor 3, the first impeller 7 rotates around the shaft axis O inside the first impeller chamber 27a, and the second impeller 8 rotates around the shaft axis O inside the second impeller chamber 29a. Thus, in the turbo fluid machine, the first impeller 7 and the second impeller 8 compress air drawn from the first inlet 14a in two steps.

Specifically, the first impeller 7 compresses the air drawn from the first inlet 14a into the first impeller chamber 27a to produce first compressed air. Then, the first compressed air flows from the first impeller chamber 27a toward the first discharge chamber 27b. That is, a pressure of the first compressed air is higher than that of the air drawn from the first inlet 14a into the first impeller chamber 27a.

The first compressed air is discharged from the first outlet 14b into the compressed fluid passage 9, flows through the first straight passage 9a, the first corner passage 9e, the second straight passage 9b, the second corner passage 9f, the third straight passage 9c, the first flow straightening passages 31a to 31g, the third corner passage 9g, and the fourth straight passage 9d in this order, and is supplied from the second inlet 15a into the second impeller chamber 29a.

The second impeller 8 further compresses the first compressed air supplied into the second impeller chamber 29a to produce second compressed air having a pressure higher than that of the first compressed air. Then, the second compressed air flows from the second impeller chamber 29a toward the second discharge chamber 29b. As described above, the second compressed air is discharged from the second outlet 15b into the discharge piping 39, and supplied to a cathode of the fuel cell stack through the discharge piping 39.

In the turbo fluid machine of the present embodiment, the first impeller 7 and the second impeller 8 rotate around the shaft axis O, so that a rotational component is applied to each of the first compressed air and the second compressed air. In the turbo fluid machine, the first compressed air flowing through the compressed fluid passage 9 is straightened in the first flow straightening passages 31a to 31g, and is supplied into the second impeller chamber 29a.

That is, as illustrated by a dashed arrow of FIG. 2, the first compressed air discharged from the first outlet 14b passes through the first straight passage 9a, the first corner passage 9e, the second straight passage 9b, the second corner passage 9f, and the third straight passage 9c, and reaches the first flow straightening passages 31a to 31g. Then, the first compressed air having reached the first flow straightening passages 31a to 31g flows through the first flow straightening passages 31a to 31g. The inner diameter of each of the first flow straightening passages 31a to 31g corresponds to the second length L2 that is smaller than the first length L1 corresponding to the inner diameter of the third straight passage 9c. Thus, a diameter of each of the first flow straightening passages 31a to 31g is smaller than that of the third straight passage 9c, and the second passage cross-sectional area S2 is smaller than the first passage cross-sectional area S1. That is, an internal space of each of the first flow straightening passages 31a to 31g is narrower than that of the third straight passage 9c.

Thus, the first compressed air is gradually straightened while flowing through the first flow straightening passages 31a to 31g, which reduces the rotational component of the first compressed air. As a result, the first compressed air having passed through the first flow straightening passages 31a to 31g flows through the third corner passage 9g and the fourth straight passage 9d in a state where the rotational component of the first compressed air is reduced as compared with that of the first compressed air not having reached the first flow straightening passages 31a to 31g. Thus, the first compressed air is supplied from the second inlet 15a into the second impeller chamber 29a in a state where the rotational component of the first compressed air is reduced as compared with that of the first compressed air when discharged from the first outlet 14b.

As described above, in the turbo fluid machine of the present embodiment, when the second impeller 8 compresses the first compressed air to produce the second compressed air, the pressure of the second compressed air increases sufficiently. Thus, in the turbo fluid machine of the present embodiment, the second compressed air with high pressure is supplied to the cathode of the fuel cell stack. To be exact, part of the first compressed air flows through gaps between the first flow straightening passages 31a to 31g and between each of the first flow straightening passages 31a to 31g and the third straight passage 9c. Then, the part of the first compressed air having flowed through the gaps and the first compressed air having flowed through the first flow straightening passages 31a to 31g are supplied into the second impeller chamber 29a and compressed by the second impeller 8.

Here, each of the first flow straightening passages 31a to 31g is formed of the cylindrical body that extends straight and has the second passage cross-sectional area S2 smaller than the first passage cross-sectional area S1, specifically, of a known pipe. Furthermore, a sum of the seven second passage cross-sectional areas S2 corresponding to the number of the first flow straightening passages 31a to 31g is smaller than the first passage cross-sectional area S1. As a result, in the turbo fluid machine of the present embodiment, the first compressed air is suitably straightened while flowing through the first flow straightening passages 31a to 31g, although a configuration of each of the first flow straightening passages 31a to 31g is simplified to achieve downsizing and reduction of a manufacturing cost of the turbo fluid machine. In the turbo fluid machine of the present embodiment, an increase in size of the third straight passage 9c, then an increase in size of the compressed fluid passage 9, is suppressed, although the first flow straightening passages 31a to 31g are provided inside the compressed fluid passage 9.

Therefore, in the turbo fluid machine of the first embodiment, the downsizing and the reduction of the manufacturing cost of the turbo fluid machine are achieved with a high compression performance.

In particular, the first flow straightening passages 31a to 31g are provided in the third straight passage 9c at a position closer to the second impeller chamber 29a than to the first impeller chamber 27a. Thus, in the turbo fluid machine of the present embodiment, a pressure drop of the first compressed air is minimized as much as possible during a period of time until the first compressed air passes through the first flow straightening passages 31a to 31g and is supplied from the second inlet 15a to the second impeller chamber 29a.

Since the first flow straightening passages 31a to 31g are each formed of the cylindrical body, the first compressed air suitably flows through the first flow straightening passages 31a to 31g as compared with a case where the first flow straightening passages 31a to 31g are each formed of a rectangular tubular body, for example. Therefore, it is possible to reduce the pressure drop of the first compressed air flowing through the first flow straightening passages 31a to 31g.

Second Embodiment

In a turbo fluid machine of a second embodiment, the first impeller 7 and the second impeller 8 (see FIG. 1) are each made of aluminum alloy. As illustrated in FIG. 5 and FIG. 6, in the turbo fluid machine of the present embodiment, seven second flow straightening passages 33a to 33g are provided inside the third straight passage 9c. Each of the second flow straightening passages 33a to 33g is an example of a “flow straightening passage” of the present disclosure.

The second flow straightening passages 33a to 33g have the same configuration. As illustrated in FIG. 5, the second flow straightening passages 33a to 33g are each formed of a cylindrical body that is made of metal and extends straight in a direction parallel to the longitudinal direction of the third straight passage 9c. Specifically, the second flow straightening passages 33a to 33g are each formed of a known pipe made of metal. As a result, the first compressed air flows through the second flow straightening passages 33a to 33g. Any number of the second flow straightening passages 33a to 33g may be appropriately set as long as a plurality of second flow straightening passages is provided. The second flow straightening passages 33a to 33g may be formed of a cylindrical body made of resin.

Here, an inner diameter of each of the second flow straightening passages 33a to 33g corresponds to a third length L3. The third length L3 is smaller than the second length L2 corresponding to the inner diameter of each of the first flow straightening passages 31a to 31g of the first embodiment. Thus, as illustrated in FIG. 7B, a third passage cross-sectional area S3 that is a cross-sectional area of each of the second flow straightening passages 33a to 33g is smaller than the first passage cross-sectional area S1 that is a cross-sectional area of the third straight passage 9c illustrated in FIG. 7A. Furthermore, a sum of seven third passage cross-sectional areas S3 corresponding to the number of the second flow straightening passages 33a to 33g is smaller than the first passage cross-sectional area S1. Features of the second flow straightening passages 33a to 33g other than the above-described feature of the present embodiment are the same as those of the first flow straightening passages 31a to 31g. A mounting of the second flow straightening passages 33a to 33g to the third straight passage 9c will be described later.

As illustrated in FIG. 5, in the turbo fluid machine of the present embodiment, the compressed fluid passage 9 has a cooling portion 41. The cooling portion 41 includes a first connection port 41a, a second connection port 41b, a supply piping 41c, a return piping 41d, a pump 41e, a first partition wall 41f, a second partition wall 41g, and a cooling chamber 41h.

The first connection port 41a and the second connection port 41b are distanced from each other in the third straight passage 9c. Specifically, the first connection port 41a and the second connection port 41b are each disposed at a position where each of the second flow straightening passages 33a to 33g is provided in the third straight passage 9c. Then, the first connection port 41a is formed downstream in a flowing direction of the first compressed air relative to the second connection port 41b. The first connection port 41a and the second connection port 41b each extend into the third straight passage 9c in its radial direction, which allows an inside and an outside of the third straight passage 9c to communicate with each other.

One end of the supply piping 41c is connected to the first connection port 41a, and the other end of the supply piping 41c is connected to a radiator (not illustrated) of the vehicle. One end of the return piping 41d is connected to the radiator, and the other end of the return piping 41d is connected to the second connection port 41b. Cooling liquid 43 (see FIG. 8) such as water and long life coolant flows through the supply piping 41c and the return piping 41d. The pump 41e illustrated in FIG. 5 is provided in the supply piping 41c. Through the supply piping 41c and the return piping 41d, the cooling liquid 43 is circulated through the cooling chamber 41h and the radiator. The pump 41e may be provided in the return piping 41d.

The first partition wall 41f and the second partition wall 41g are each made of resin such as synthetic rubber and have the same configuration. The following will describe the first partition wall 41f. As illustrated in FIG. 6, the first partition wall 41f has a disc shape, and a diameter of the first partition wall 41f corresponds to the first length L1 that is the same length as the inner diameter of the third straight passage 9c. Seven mounting holes 411 to 417 extend through the first partition wall 41f. The first partition wall 41f and the second partition wall 41g may be made of metal.

As illustrated in FIG. 5, the first partition wall 41f and the second partition wall 41g are provided inside the third straight passage 9c and distanced from each other in the flowing direction of the first compressed air. Specifically, in the third straight passage 9c, the first partition wall 41f is provided upstream in the flowing direction of the first compressed air relative to the second connection port 41b, and the second partition wall 41g is provided downstream in the flowing direction of the first compressed air relative to the first connection port 41a. The first partition wall 41f and the second partition wall 41g are in close contact with and bonded to the inner peripheral surface 901 of the third straight passage 9c. Thus, the first partition wall 41f and the second partition wall 41g partition the inside of the third straight passage 9c.

The cooling chamber 41h is formed between the first partition wall 41f, the second partition wall 41g and the inner peripheral surface 901 in the third straight passage 9c. The first partition wall 41f and the second partition wall 41g seal a gap between an inside and an outside of the cooling chamber 41h. The supply piping 41c is connected to the cooling chamber 41h via the first connection port 41a, and the return piping 41d is connected to the cooling chamber 41h via the second connection port 41b.

The second flow straightening passages 33a to 33g are inserted into mounting holes 411 to 417 of the first partition wall 41f and the second partition wall 41g, respectively. Specifically, as illustrated in FIG. 6, the second flow straightening passage 33a is inserted into the mounting hole 411, the second flow straightening passage 33b is inserted into the mounting hole 412, the second flow straightening passage 33c is inserted into the mounting hole 413, the second flow straightening passage 33d is inserted into the mounting hole 414, the second flow straightening passage 33e is inserted into the mounting hole 415, the second flow straightening passage 33f is inserted into the mounting hole 416, and the second flow straightening passage 33g is inserted into the mounting hole 417. As a result, the second flow straightening passages 33a to 33g are fixed to the first partition wall 41f and the second partition wall 41g in a state where the second flow straightening passage 33a is positioned in a central portion of the third straight passage 9c and the second flow straightening passages 33b to 33g are arranged in a circumferential direction of the second flow straightening passage 33a.

As described above, the second flow straightening passages 33a to 33g are provided inside the cooling chamber 41h and fixed to the first partition wall 41f and the second partition wall 41g. Here, in the turbo fluid machine of the present embodiment, gaps between the second flow straightening passages 33a to 33g and a gap between each of the second flow straightening passages 33a to 33g and the inner peripheral surface 901 of the third straight passage 9c are widened as compared with those of the turbo fluid machine of the first embodiment. Features other than the above-described feature of the turbo fluid machine of the present embodiment are the same as those of the turbo fluid machine of the first embodiment. The same elements are designated by the same reference numerals, and the redundant descriptions thereof are omitted.

In the turbo fluid machine of the present embodiment, the first compressed air having reached the second flow straightening passages 33a to 33g flows through the second flow straightening passages 33a to 33g. As a result, in the turbo fluid machine of the present embodiment, the first compressed air is supplied from the second inlet 15a into the second impeller chamber 29a in a state where the rotational component of the first compressed air is reduced, as in the turbo fluid machine of the first embodiment.

In the turbo fluid machine of the present embodiment, as illustrated in FIG. 8, the pump 41e is operated so that the cooling liquid 43 flows from the supply piping 41c into the cooling chamber 41h. Then, in the cooling chamber 41h, heat is exchanged between the first compressed air flowing through the second flow straightening passages 33a to 33g and the cooling liquid 43. Thus, the cooling portion 41 cools the first compressed air flowing through the second flow straightening passages 33a to 33g.

In the cooling portion 41, the first connection port 41a is provided downstream in the flowing direction of the first compressed air relative to the second connection port 41b. Therefore, as shown by a solid arrow of FIG. 5, the cooling liquid 43 having flowed from the supply piping 41c into the cooling chamber 41h flows upstream in the flowing direction of the first compressed air, specifically, flows toward the second connection port 41b and the return piping 41d. Then, the flowing direction of the first compressed air flowing through the second flow straightening passages 33a to 33g is opposite to a flowing direction of the cooling liquid 43 flowing inside the cooling chamber 41h. Thus, the heat is suitably exchanged between the first compressed air flowing through the second flow straightening passages 33a to 33g and the cooling liquid 43, so that the cooling portion 41 cools the first compressed air sufficiently.

As described above, in the turbo fluid machine of the present embodiment, since the first compressed air is cooled and supplied into the second impeller chamber 29a, the second impeller 8 need not have an excessive high heat resistance. Thus, in the turbo fluid machine of the present embodiment, the second impeller 8 is made of aluminum alloy, which reduces a weight of the second impeller 8 and reduces a manufacturing cost of the turbo fluid machine.

In the turbo fluid machine of the present embodiment, the cooling portion 41 cools the first compressed air, which prevents the second compressed air from increasing a temperature thereof. Therefore, it is not necessary to provide a cooling portion for cooling the second compressed air. In the turbo fluid machine of the present embodiment, it is prevented that the temperature of the compressed fluid passage 9 is increased by the first compressed air, which further prevents the housing 1 from increasing a temperature thereof due to heat of the compressed fluid passage 9. Operations other than the above-described operation of the turbo fluid machine of the present embodiment are the same as those of the turbo fluid machine of the first embodiment.

Third Embodiment

As illustrated in FIG. 9, in a turbo fluid machine of a third embodiment, four third flow straightening passages 35a to 35d are provided in the third straight passage 9c. Each of the third flow straightening passages 35a to 35d is an example of a “flow straightening passage” of the present disclosure. In the turbo fluid machine of the present embodiment, a division plate 45 is provided inside the third straight passage 9c.

The division plate 45 is made of metal, extends in a cross shape in the radial direction of the third straight passage 9c, and extends straight in a longitudinal direction of the division plate 45 parallel to the third straight passage 9c. Here, a length of the division plate 45 in the radial direction of the third straight passage 9c is equal to the first length L1 corresponding to the inner diameter of the third straight passage 9c. A length of the division plate 45 in its longitudinal direction is the same as the above-described length of each of the first flow straightening passages 31a to 31g, which is not illustrated. The division plate 45 may have any shape as appropriate. The division plate 45 may be made of resin.

The division plate 45 divides the third straight passage 9c into the third flow straightening passages 35a to 35d inside the third straight passage 9c. Since the division plate 45 extends straight in its longitudinal direction parallel to the third straight passage 9c, each of the third flow straightening passages 35a to 35d also extends straight in its longitudinal direction parallel to the third straight passage 9c.

A cross section of each of the third flow straightening passages 35a to 35d in a direction perpendicular to the flowing direction of the first compressed air has a circular sector shape in which the third straight passage 9c is substantially divided into four parts. Thus, as illustrated in FIG. 10B, a fourth passage cross-sectional area S4 that is a cross-sectional area of each of the third flow straightening passages 35a to 35d is smaller than the first passage cross-sectional area S1 that is a cross-sectional area of the third straight passage 9c illustrated in FIG. 10A. A sum of four fourth passage cross-sectional areas S4 corresponding to the number of the third flow straightening passages 35a to 35d is smaller than the first passage cross-sectional area S1. Features other than the above-described feature of the turbo fluid machine of the third embodiment are the same as those of the turbo fluid machine of the first embodiment.

In the turbo fluid machine of the present embodiment, the first compressed air having reached the third flow straightening passages 35a to 35d flows through the third flow straightening passages 35a to 35d. As a result, in the turbo fluid machine of the present embodiment, the first compressed air is supplied from the second inlet 15a into the second impeller chamber 29a in a state where the rotational component of the first compressed air is reduced. In the turbo fluid machine of the present embodiment, the division plate 45 is provided inside the third straight passage 9c, which easily arranges the third flow straightening passages 35a to 35d inside the third straight passage 9c. Thus, in the turbo fluid machine of the present embodiment, a configuration of each of the third flow straightening passages 35a to 35d is simplified. Operations other than the above-described operation of the turbo fluid machine of the third embodiment are the same as those of the turbo fluid machine of the first embodiment.

As described above, although the present disclosure has been described in accordance with the first to third embodiments, the present disclosure is not limited by the first to third embodiments and may be appropriately modified without departing from the scope of the disclosure.

For example, in the turbo fluid machine of the first embodiment, although the first flow straightening passages 31a to 31g are provided in the third straight passage 9c of the compressed fluid passage 9, the first flow straightening passages 31a to 31g may be provided in the first straight passage 9a, the fourth straight passage 9d, or the like. The same applies to the turbo fluid machine of each of the second and third embodiments.

In the turbo fluid machine of the first embodiment, the first flow straightening passages 31a to 31g may be provided in a plurality of portions of the compressed fluid passage 9. The same applies to the turbo fluid machine of each of the second and third embodiments.

In the turbo fluid machine of each of the first to third embodiments, the compressed fluid passage 9 may be formed integrally with the housing 1 in its inside.

In the turbo fluid machine of each of the first to third embodiments, although air serves as “fluid” of the present disclosure, refrigerant used for air conditioning may serve as the “fluid” of the present disclosure.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to a fuel cell system, an air conditioner, and the like.

Claims

1. A turbo fluid machine comprising:

a housing including an impeller chamber and a motor chamber;
an electric motor accommodated in the motor chamber,
an impeller that is accommodated in the impeller chamber and compresses fluid with rotation of the electric motor; and
a drive shaft that is accommodated in the housing and connects the impeller and the electric motor, wherein
the impeller chamber includes a first impeller chamber and a second impeller chamber distanced from each other in an axial direction of the drive shaft,
the impeller includes: a first impeller that is accommodated in the first impeller chamber and compresses the fluid to produce first compressed fluid; and a second impeller that is accommodated in the second impeller chamber and compresses the first compressed fluid to produce second compressed fluid, and
the turbo fluid machine further includes: a compressed fluid passage through which the first compressed fluid is supplied to the second impeller chamber; and a plurality of flow straightening passages that extends inside the compressed fluid passage in a direction in which the compressed fluid passage extends, and through which the first compressed fluid is straightened and supplied to the second impeller chamber.

2. The turbo fluid machine according to claim 1, wherein

each of the flow straightening passages is disposed at a position closer to the second impeller chamber than to the first impeller chamber.

3. The turbo fluid machine according to claim 1, wherein

each of the flow straightening passages is formed of a cylindrical body extending straight.

4. The turbo fluid machine according to claim 1, wherein

the compressed fluid passage includes a cooling portion configured to cool the first compressed fluid flowing through each of the flow straightening passages.
Patent History
Publication number: 20230258200
Type: Application
Filed: Feb 2, 2023
Publication Date: Aug 17, 2023
Applicant: KABUSHIKI KAISHA TOYOTA JIDOSHOKKI (Aichi)
Inventor: Ryo UMEYAMA (Kariya-shi)
Application Number: 18/104,980
Classifications
International Classification: F04D 29/42 (20060101); F04D 17/10 (20060101); F04D 25/06 (20060101);