Centrifugal air compressor, assembly method, test method and hydrogen fuel cell

Abstract

A centrifugal air compressor, an assembly method, a test method and a hydrogen fuel cell. The centrifugal air compressor comprises a motor assembly (10), compression assemblies (20), and a bearing assembly (30). The motor assembly (10) comprises a base (11), a stator (12), a rotor (13), bearing blocks (15) and end covers (16), the stator (12) being connected to the base (11). The two axial ends of the motor assembly (10) are connected to the compression assemblies (20), each compression assembly (20) comprising an impeller (21) and a volute (22). The bearing assembly (30) comprises a radial air bearing (31), a thrust disc (32), thrust bearings (33) and check rings (34), each bearing block (15) being connected to the rotor (13) by means of the radial air bearing (31), and the two sides of the thrust disc (32) respectively being provided with the thrust bearings (33). The two ends of the radial air bearing (31) are provided with the check rings (34) to stop foils of the radial air bearing (31), the check rings (34) being connected to the bearing blocks (15). The centrifugal air compressor, the assembly method, the test method and the hydrogen fuel cell can prevent foils from slipping off during the assembly of stators and rotors and the lift-off of the rotors, thus ensuring the working efficiency of the centrifugal air compressor, prolonging the service life of the centrifugal air compressor, and improving the reliability of the centrifugal air compressor.

Description

A centrifugal air compressor, assembly method, detection method and hydrogen fuel cell

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202311627266.4 and application date of November 30, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present invention is used in the field of air compressors, and in particular relates to a centrifugal air compressor, an assembly method, a detection method, and a hydrogen fuel cell. Background Art

[0004] In the hydrogen fuel cell industry chain, air compressors play a vital role in hydrogen fuel cell systems and are key components. Due to their compact structure, small size, good sealing, light weight, low vibration, and high efficiency under rated operating conditions, they are considered one of the most promising air compression methods in the future. During the assembly and disassembly of the stator and rotor of a centrifugal air compressor, the rotor rubs against the foil of the radial air bearing, pulling the foil out of the radial air bearing. During takeoff, the rotor contacts the foil, and changes in the magnitude and direction of the axial force can easily cause the foil to be pulled out of the radial air bearing. Inconsistent installation angles of the radial air bearing foil can easily lead to radial air bearing failure.

[0005] Summary of the Invention

[0006] In view of this, the embodiments of the present application hope to provide a centrifugal air compressor and an assembly method, a detection method and a hydrogen fuel cell to prevent the foil from slipping out of the radial air bearing under the action of friction when the stator and rotor are assembled and the rotor rotates for takeoff, thereby ensuring the working efficiency of the centrifugal air compressor and improving the service life, assembly accuracy and reliability of the air compressor.

[0007] To achieve the above-mentioned object, a first aspect of an embodiment of the present application provides a centrifugal air compressor, comprising a motor assembly, a compression assembly, and a bearing assembly;

[0008] The motor assembly includes a base, a stator, a rotor, a bearing seat and an end cover, the axial ends of the base are respectively connected to the bearing seats, the outer side of the bearing seat at each end is connected to the end cover, the two ends of the rotor are respectively passed through the corresponding bearing seat and the end cover, and the stator is connected to the base; the axial ends of the motor assembly are respectively connected to the compression assembly, each of the compression assemblies includes an impeller and a volute, the impeller is arranged at one end of the rotor and is sealed with the corresponding end cover, the volute cover is arranged on the outer side of the impeller, the volute is respectively connected to the corresponding bearing seat and the end cover, and the bearing seat, the end cover and the volute at the corresponding end are surrounded to form a compression chamber;

[0009] The bearing assembly includes a radial air bearing, a thrust plate, a thrust bearing and a retaining ring mounted on the rotor. Each bearing seat is connected to the rotor through the radial air bearing. The thrust plate is arranged at one end of the rotor and is located between the corresponding bearing seat and the end cover. The thrust bearings are respectively arranged on both sides of the thrust plate. The retaining rings are respectively arranged at both ends of the radial air bearing, and the retaining rings are connected to the bearing seat to stop the foil of the radial air bearing.

[0010] In some embodiments, the bearing seat has a step wall and a step cavity, the retaining ring is divided into a first retaining ring and a second retaining ring, the bearing assembly also includes a positioning pin, and the step wall, the first retaining ring and the radial air bearing all have corresponding positioning holes; the radial air bearing is located in the step cavity, the first retaining ring is located between the step wall and the radial air bearing, and the second retaining ring is arranged at the other end of the radial air bearing away from the inner retaining ring; the positioning pin is passed through each of the positioning holes to position the foil slot angle of the radial air bearing.

[0011] In some embodiments, the bearing assembly further includes a mounting pin, and the thrust plate, the two thrust bearings, and the bearing seat and the end cover at the corresponding ends respectively have corresponding pin holes, and the mounting pin is passed through each of the pin holes; the mounting pin is interference fit with the pin hole on the bearing seat, the mounting pin and the pin holes on the two thrust bearings are both clearance fit, and the mounting pin is clearance fit with the pin hole on the end cover.

[0012] In some embodiments, the end cover is divided into a first end cover away from one end of the thrust disc and a second end cover close to one end of the thrust disc, the bearing seat is divided into a first bearing seat away from one end of the thrust disc and a second bearing seat close to one end of the thrust disc, and the thrust bearing is divided into a first thrust bearing close to the second end cover and a second thrust bearing close to the second bearing seat;

[0013] The first end cover has a first air inlet hole connected to the compression chamber at the corresponding end, a first air inlet cavity is formed between the first end cover and the first bearing seat, and the first bearing seat has a first vent hole; air in the compression chamber enters the first air inlet cavity through the first air inlet hole, and enters the machine base through the gap between the corresponding radial air bearing and the rotor to form a first air-cooling flow channel; air in the compression chamber enters the first air inlet cavity through the first air inlet hole, and enters the machine base through the first vent hole to form a second air-cooling flow channel;

[0014] The second bearing seat is provided with a second air inlet hole and a second air vent hole, a first flow channel is formed between the second end cover and the first thrust bearing, and a second flow channel is formed between the second bearing seat and the second thrust bearing; air enters the first flow channel through the second air inlet hole, and enters the machine base through the second flow channel and the corresponding gap between the radial air bearing and the rotor to form a third air-cooling flow channel; air enters the first flow channel through the second air inlet hole, and enters the machine base through the second flow channel and the second air vent hole to form a fourth air-cooling flow channel.

[0015] In some embodiments, the second air inlet is connected to the compression chamber at the corresponding end, or the second air inlet is connected to the air-cooling channel in the machine base; and / or, the machine base has an air outlet, and the first air-cooling channel, the second air-cooling channel, the third air-cooling channel and the fourth air-cooling channel are all connected to the air outlet.

[0016] In some embodiments, the second end cover has a second air inlet cavity located inside, a first annular groove located in the middle area of ​​the side, and a first air inlet groove located on the side, the second air inlet cavity is connected to the first air inlet groove through the first annular groove, and the first air inlet groove and the first annular groove form the first flow channel; and / or, the second bearing seat has a second air inlet groove extending radially inward to form the second flow channel, the second air vent is located inside the second bearing seat, and is connected to the second flow channel at the rotor.

[0017] In some embodiments, the centrifugal air compressor further includes a sealing assembly, which includes a first sealing structure, a second sealing structure, and a third sealing structure; the first sealing structure is arranged between the end cover and the rotor and between the thrust plate and the end cover; the second sealing structure is arranged between the impeller and the end cover; and the third sealing structure is arranged between the end cover and the volute.

[0018] A second aspect of the embodiments of the present application further provides an assembly method, which is applied to any one of the centrifugal air compressors described above, and the assembly method comprises:

[0019] Mounting the machine base provided with the stator on a slider capable of moving along a slide rail;

[0020] Connect the bearing seat at one end to the machine base, and install the corresponding radial air bearing;

[0021] Installing the bearing seat at the other end and the corresponding radial air bearing on the rotor;

[0022] Axially positioning the rotor using an ejector pin device;

[0023] Adjusting the height adjustment base supporting the ejector device so that the rotor is aligned with the axis of the machine base;

[0024] The base is slid toward the rotor so that the stator and the rotor on the base are aligned.

[0025] In some embodiments, the step of axially positioning the rotor using a thimble device specifically includes:

[0026] In an initial state where the ejector pin device performs axial positioning on the rotor, the base and the rotor are spaced apart.

[0027] A third aspect of the embodiments of the present application further provides a detection method, which is applied to any one of the centrifugal air compressors described above, and the detection method includes:

[0028] Using a pre-tightening torque wrench to detect the pre-tightening torque of the rotor;

[0029] A takeoff speed of the rotor is predicted based on the preload torque.

[0030] A fourth aspect of the embodiments of the present application further provides a hydrogen fuel cell comprising any one of the centrifugal air compressors described above.

[0031] The centrifugal air compressor, assembly method, detection method and hydrogen fuel cell provided in the present application can solve the problem of friction between the rotor and the foil of the radial air bearing, causing the foil to be pulled out of the radial air bearing during the assembly and disassembly of the stator and rotor; can solve the problem of the rotor and the foil contacting when the rotor takes off, causing the foil to be pulled out of the radial air bearing due to changes in the magnitude and direction of the axial force; can solve the problem of difficulty in installing the foil; and solve the problem of failure of the radial air bearing due to inconsistent foil installation angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic diagram of the overall structure of a centrifugal air compressor according to some embodiments of the present application;

[0033] FIG2 is a schematic diagram of a partially enlarged structure of point A in FIG1 ;

[0034] FIG3 is a schematic diagram of a partially enlarged structure of point B in FIG1 ;

[0035] FIG4 is a schematic diagram of an air cooling channel of a centrifugal air compressor according to some embodiments of the present application;

[0036] FIG5 is a schematic structural diagram of a first end cover of a centrifugal air compressor according to some embodiments of the present application;

[0037] FIG6 is a schematic structural diagram of a first bearing seat of a centrifugal air compressor according to some embodiments of the present application;

[0038] FIG7 is a schematic cross-sectional view of a second end cover of a centrifugal air compressor according to some embodiments of the present application;

[0039] FIG8 is a schematic side view of the structure of a second end cover of a centrifugal air compressor according to some embodiments of the present application;

[0040] FIG9 is a schematic cross-sectional view of a second bearing seat of a centrifugal air compressor according to some embodiments of the present application;

[0041] FIG10 is a side view of a second bearing seat of a centrifugal air compressor according to some embodiments of the present application;

[0042] FIG11 is a schematic cross-sectional view of a centrifugal air compressor base according to some embodiments of the present application;

[0043] FIG12 is a schematic diagram of an installation device for a centrifugal air compressor according to some embodiments of the present application;

[0044] FIG13 is a schematic flow chart of an assembly method for a centrifugal air compressor according to some embodiments of the present application;

[0045] FIG14 is a flow chart of a detection method for a centrifugal air compressor according to some embodiments of the present application.

[0046] Reference numerals in the figure: motor assembly 10; base 11; air outlet 11a; spiral channel 11b; stator 12; rotor 13; bearing seat 15; step wall 15a; step cavity 15b; first bearing seat 151; first air vent 151a; second bearing seat 152; second air inlet hole 152a; second air vent 152b; second air inlet groove 152c; end cover 16; first end cover 161; first air inlet hole 161a; second end cover 162; second air inlet cavity 162a; first annular groove 162b; first air inlet groove 162c; first air-cooling channel a; first air inlet cavity a1; second air-cooling channel b; third air-cooling channel c; first flow channel c1; second flow channel c2; fourth air-cooling channel d;

[0047] Compression assembly 20; impeller 21; volute 22; compression chamber 20a; locking nut 23;

[0048] Bearing assembly 30; radial air bearing 31; thrust plate 32; thrust bearing 33; first thrust bearing 331; second thrust bearing 332; retaining ring 34; first retaining ring 341; second retaining ring 342; positioning pin 35; mounting pin 36;

[0049] Sealing assembly 40; first sealing structure 41; second sealing structure 42; third sealing structure 43; fourth sealing structure 44;

[0050] Mounting device 50; slide rail 51; slider 52; ejector device 53; ejector seat 531; ejector 532; ejector column 533; guide column 534; height adjustment seat 54; first height adjustment seat 541; second height adjustment seat 542. DETAILED DESCRIPTION

[0051] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0052] In the description of the embodiments of the present application, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0053] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0054] In the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0055] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0056] In the prior art, during the assembly and disassembly process of the stator and rotor in the centrifugal air compressor, the rotor rubs against the foil of the radial air bearing, which can easily pull the foil out of the radial air bearing. In addition, during the operation of the centrifugal air compressor, when the rotor takes off, the rotor contacts the foil, and due to the changes in the magnitude and direction of the axial force, the foil can also be easily pulled out of the radial air bearing.

[0057] In view of this, a first aspect of an embodiment of the present application provides a centrifugal air compressor. Please refer to Figures 1 to 3. The centrifugal air compressor includes a motor assembly 10, a compression assembly 20 and a bearing assembly 30.

[0058] Motor assembly 10 includes a base 11, stator 12, rotor 13, bearing seat 15, and end caps 16. Bearing seats 15 are connected to each axial end of base 11, and end caps 16 are attached to the outer sides of the bearing seats 15 at each end. The ends of rotor 13 are respectively inserted into the corresponding bearing seats 15 and end caps 16, and stator 12 is connected to base 11. During operation of the centrifugal air compressor, rotor 13 rotates under the electromagnetic induction force of stator 12, causing rotor 13 to output power.

[0059] A compression assembly 20 is connected to both axial ends of the motor assembly 10. The compression assembly 20 includes an impeller 21 and a volute 22. The impeller 21 is arranged at one end of the rotor 13. The impeller 21 is sealed with the end cover 16. The volute 22 is arranged on the outside of the impeller 21. The volute 22 is connected to the bearing seat 15 and the end cover 16 respectively. For example, the volute 22 is tightly connected to the bearing seat 15, and the volute 22 is sealed with the end cover 16. The bearing seat 15, the end cover 16 and the volute 22 at the corresponding ends are surrounded to form a compression chamber 20a. The locking nut 23 fixes the impeller 21 to both ends of the rotor 13. The compression assembly 20 is used to compress the air. When the centrifugal air compressor is in operation, the rotor 13 can run at high speed under the action of the electromagnetic induction force of the stator 12, driving the two impellers 21 to rotate together to achieve air compression.

[0060] The bearing assembly 30 includes a radial air bearing 31, a thrust plate 32, a thrust bearing 33, and a retaining ring 34. The radial air bearing 31 is mounted on the rotor 13. Each bearing seat 15 is connected to the rotor 13 via the radial air bearing 31. The thrust plate 32 is located at one end of the rotor 13 and is positioned between the rotor 13 and the end cover 16. Thrust bearings 33 are provided on both sides of the thrust plate 32. For example, the thrust plate 32 includes a plate body and sleeves connected to both sides of the plate body. The end cover 16 is mounted on the sleeve on one side of the plate body. Thrust bearings 33 are provided on both sides of the plate body. The radial air bearing 31 is used to bear the radial load of the rotor 13; the thrust bearing 33 is used to bear the axial load of the rotor 13 and limit the axial movement of the rotor 13.

[0061] A retaining ring 34 is provided at both ends of the radial air bearing 31 . The retaining ring 34 is connected to the bearing seat 15 and can block the foil of the radial air bearing 31 to prevent the foil from being pulled out of the inner cavity of the radial air bearing 31 .

[0062] Specifically, referring to Figure 2 , the bearing housing 15 has a stepped wall 15a and a stepped cavity 15b, with the radial air bearing 31 located within the stepped cavity 15b. A retaining ring 34 comprises a first retaining ring 341 and a second retaining ring 342. The first retaining ring 341 is located between the stepped wall 15a and the radial air bearing 31, while the second retaining ring 342 is located at the other end of the radial air bearing 31, away from the first retaining ring 341. The retaining rings 34 are located on both ends of the radial air bearing 31 to effectively prevent the foil from slipping out of the inner cavity of the radial air bearing 31 due to friction during assembly of the stator 12 and rotor 13 and during takeoff.

[0063] In some embodiments, referring to FIG. 2 , the bearing assembly 30 further includes a locating pin 35. The step wall 15a, the first retaining ring 341, and the radial air bearing 31 each have corresponding locating holes. The locating pin 35 is inserted into each locating hole to position the foil retaining slot of the radial air bearing 31 when the radial air bearing 31 is mounted on the bearing seat 15. The locating pin 35 ensures that the foil retaining slot angles of the two radial air bearings 31 are always consistent during installation, thus resolving the issue of inconsistent foil retaining slot installation angles of the radial air bearings 31 due to human error, which could render the radial air bearing 31 scrapped.

[0064] Specifically, when installing the radial air bearing 31, first install the locating pin 35 and the first retaining ring 341 on the stepped wall 15a. Then, insert the radial air bearing 31 into the bearing seat 15, install the second retaining ring 342, and bolt the second retaining ring 342 to the end of the bearing seat 15 away from the stepped wall 15a. Using the locating pin 35 to determine the installation angle of the radial air bearing 31 prevents inconsistent installation angles of the foils on both sides of the radial air bearing 31, while facilitating the installation of the first retaining ring 341. This also increases the ease and accuracy of assembly of the retaining ring 34 and radial air bearing 31, as well as the reliability of the operation of the radial air bearing 31.

[0065] For ease of understanding, please refer to Figures 1 to 3, in which the end cover 16 is divided into a first end cover 161 away from the thrust plate 32 and a second end cover 162 close to the thrust plate 32; the bearing seat 15 is divided into a first bearing seat 151 away from the thrust plate 32 and a second bearing seat 152 close to the thrust plate 32; the thrust bearing 33 is divided into a first thrust bearing 331 close to the second end cover 162, and a second thrust bearing 332 close to the second bearing seat 152.

[0066] In some embodiments, referring to FIG3 , the bearing assembly 30 further includes a mounting pin 36. The thrust plate 32, the thrust bearing 33, the second bearing seat 152, and the second end cover 162 each have corresponding pin holes, and the mounting pin 36 is passed through each pin hole to facilitate the installation and positioning of the thrust bearing 33. If screws are used to tighten the thrust bearing 33, the forces on each screw are uneven, which can easily cause the thrust bearing 33 to be not in the same plane, thereby reducing the performance of the thrust bearing 33. By installing the thrust bearing 33 by matching the mounting pin 36 with the pin hole, the disadvantages of fixing the thrust bearing 33 with screws can be avoided. This effectively improves the reliability and anti-interference performance of the thrust bearing 33 and extends the service life of the thrust bearing 33. It can also improve the efficiency of installing and disassembling the thrust bearing 33.

[0067] Specifically, the mounting pin 36 forms an interference fit with the pin hole in the second bearing seat 152, a clearance fit between the mounting pin 36 and the pin hole in the second thrust bearing 332, a clearance fit between the mounting pin 36 and the pin hole in the first thrust bearing 331, and a clearance fit between the mounting pin 36 and the pin hole in the second end cap 162. In this way, the mounting pin 36 enables the thrust bearing 33 to automatically adjust its position based on the magnitude of the axial force, thereby improving the operational reliability of the thrust bearing 33. This improves the ease of assembly and disassembly of the thrust bearing 33 while also enabling adaptive adjustment of the thrust bearing 33.

[0068] In some embodiments, the compression components 20 on both sides are connected through a connecting pipe, and the air can be compressed in two stages under the action of the compression components 20 at both ends. For example, the air can first enter the compression component 20 on the left, and the high-pressure gas generated after being compressed by the impeller 21 on the left is collected by the volute 22 on the left. The compressed air enters the compression component 20 on the right through the connecting pipe, and the impeller 21 on the right compresses the air again, and the compressed air is collected by the volute 22 on the right and delivered. Alternatively, the air can first enter the compression component 20 on the right, and the high-pressure gas generated after being compressed by the impeller 21 on the right is collected by the volute 22 on the right. The compressed air enters the compression component 20 on the left through the connecting pipe, and the impeller 21 on the left compresses the air again, and the compressed air is collected by the volute 22 on the left and delivered.

[0069] During the air compression process, centrifugal compressors generate a significant amount of heat on both sides. The high-speed rotation of the radial air bearing 31 generates heat, which, combined with heat radiation from within the centrifugal compressor, causes the temperature of the bearing assembly 30 to rise rapidly. This excessive heat causes internal components of the centrifugal compressor to overheat, leading to a series of problems such as damage to the bearing assembly 30 and motor assembly 10 due to thermal stress, severely impacting the normal operation of the centrifugal compressor.

[0070] In order to prevent the heat generated by the operation of the centrifugal air compressor from affecting its life, in some embodiments, please refer to Figure 4. The centrifugal air compressor of the embodiment of the present application introduces cooling air to cool the motor assembly 10 and the bearing assembly 30, thereby improving the efficiency and economy of cooling, reducing the operating temperature of the centrifugal air compressor, and improving the safety and reliability of the operation of each component.

[0071] In order to achieve the flow of cooling air, please refer to Figure 4. The embodiment of the present application provides four air-cooling channels to achieve sufficient and comprehensive cooling of the radial air bearing 31, thrust bearing 33, thrust plate 32, bearing seat 15, stator 12 and rotor 13.

[0072] In some embodiments, referring to Figures 4 and 5, a first air inlet hole 161a is provided on the first end cover 161, and the first air inlet hole 161a is connected to the compression chamber 20a at the corresponding end. Air for cooling is taken out from the compression chamber 20a and passes through the first air-cooling flow channel a and the second air-cooling flow channel b. The first air-cooling flow channel a and the second air-cooling flow channel b have a common channel.

[0073] Specifically, referring to Figures 4-6 , a first air inlet chamber a1 is formed between the first end cap 161 and the first bearing seat 151. The first bearing seat 151 has a first vent 151a. Air within the compression chamber enters the first air inlet chamber a1 through the first air inlet vent 161a, then flows into the base 11 through the gap between the corresponding radial air bearing 31 and the rotor 13, forming a first air-cooling channel a. This first air-cooling channel a cools the first end cap 161, the first bearing seat 151, the corresponding radial air bearing 31, the stator 12, and the rotor 13.

[0074] Air in the compression chamber enters the first air inlet chamber a1 through the first air inlet hole 161a and enters the engine base 11 through the first air vent 151a, forming a second air-cooling channel b. The second air-cooling channel b cools the first end cover 161, the first bearing seat 151, the stator 12, and the rotor 13.

[0075] Please refer to Figure 4. The second bearing seat 152 has a second air inlet hole 152a and a second air vent hole 152b. A first flow channel c1 is formed between the second end cover 162 and the first thrust bearing 331. A second flow channel c2 is formed between the second bearing seat 152 and the second thrust bearing 332.

[0076] In some embodiments, the second air inlet hole 152a is connected to the compression chamber 20a at the corresponding end or the air-cooling channel in the machine base 11 structure; the air entering from the second air inlet hole 152a enters the third air-cooling channel c and the fourth air-cooling channel d for cooling, and the third air-cooling channel c and the fourth air-cooling channel d have a shared channel.

[0077] Air enters the first flow channel c1 through the second air inlet 152a, then flows into the base 11 through the second flow channel c2 and the gap between the corresponding radial air bearing 31 and the rotor 13, forming the third air-cooling flow channel c. This third air-cooling flow channel c cools the second bearing seat 152, the second end cover 162, the thrust bearing 33, the thrust plate 32, the corresponding radial air bearing 31, and the rotor 13.

[0078] Air enters the first flow channel c1 through the second air inlet 152a, and then enters the machine base 11 through the second flow channel c2 and the second vent 152b, forming a fourth air-cooling flow channel d. This fourth air-cooling flow channel d cools the second bearing seat 152, the second end cover 162, the thrust bearing 33, and the thrust plate 32.

[0079] Specifically, please refer to Figures 7 and 8. The second end cover 162 has a second air intake cavity 162a located inside, a first annular groove 162b located in the middle area of ​​the side, and a first air intake groove 162c located on the side, wherein the first air intake groove 162c is connected to the first air intake groove 162c through the first annular groove 162b, and the first air intake groove 162c and the first annular groove 162b form a first flow channel c1.

[0080] Before entering the cooling channel, the air extracted from the compression chamber 20a is depressurized in the first air inlet chamber a1 or the second air inlet chamber 162a. After depressurization, it enters the motor assembly 10. This prevents the air compressed by the impeller 21 from directly entering the motor assembly 10, which could cause problems such as low cooling efficiency, severe damage to the winding insulation, and increased axial force on the rotor 13 due to high pressure. This effectively improves the cooling effect and extends the service life of the centrifugal air compressor.

[0081] Specifically, please refer to Figures 9 and 10. The second bearing seat 152 has a second air inlet groove 152c that extends radially inward to form a second flow channel c2. The second air vent 152b is located inside the second bearing seat 152 and is connected to the second flow channel c2 at the rotor 13.

[0082] Please continue to refer to Figure 4. The air in the compression chamber enters the second air intake chamber 162a in the second end cover 162 through the second air intake hole 152a, and at the same time passes through the first flow channel c1 formed by the first air intake groove 162c and the first annular groove 162b, and the second flow channel c2 formed by the second air intake groove 152c on the second bearing seat 152, and then passes through the gap between the corresponding radial air bearing 31 and the rotor 13 to enter the machine base 11, so as to cool the second bearing seat 152, the second end cover 162, the thrust bearing 33, the thrust plate 32, the corresponding end radial air bearing 31 and the rotor.

[0083] In order to further enhance the cooling effect, please refer to Figures 7 to 10. The second air inlet cavity 162a and the first flow channel 162c adopt a divergent multi-channel design on the second end cover 162, and the second air vent 152b and the second flow channel 152c adopt a divergent multi-channel design on the second bearing seat 152, so that the cooling flow channels are evenly distributed on the thrust bearing 33, which can increase the contact area between the thrust bearing 33 and the cooling gas, thereby increasing the heat dissipation area of ​​the thrust bearing 33.

[0084] For example, there are three second air inlet cavities 162a, and there are six first flow channels 162c and six second flow channels 152c. The flow area of ​​each second air inlet cavity 162a is greater than the flow area of ​​each first flow channel 162c. The flow area of ​​each second air inlet cavity 162a is greater than the flow area of ​​each second flow channel 152c. In some embodiments, according to the cooling conditions of the second bearing seat 152, the second end cover 162, the radial air bearing 31, the thrust bearing 33, the rotor 13, and the stator 12, the opening diameter and cross-sectional area of ​​the first air inlet slot 162c and the second air inlet slot 152c are adjusted in combination with design requirements to achieve distribution management of the cooling air volume of each air-cooling channel.

[0085] By diverting and converging the four air-cooling channels and adjusting the air inlet area through the first air inlet slot 162c and the second air inlet slot 152c, the paths of the air-cooling channels can be planned as needed, and thermal management can be performed on the various structures within the centrifugal air compressor to avoid problems such as local high temperatures in the internal structures of the centrifugal air compressor and low heat dissipation efficiency of the entire machine, thereby meeting the differentiated demands for cooling air volume when different structures within the centrifugal air compressor generate heat.

[0086] In some embodiments, the second air inlet hole 152a can be connected to the outside to provide cooling air.

[0087] In some embodiments, referring to Figure 4 , the base 11 is provided with an air outlet 11a. Four air-cooling channels are connected to the air outlet 11a on the base 11. Air is discharged from the air outlet 11a after cooling the motor assembly 10, the bearing assembly 30, and the interior of the housing. For example, the air outlet 11a may be located at one end of the base 11, with air from the air-cooling channel at the other end flowing toward the air outlet 11a through the air gap between the rotor 13 and the stator 12. Alternatively, an air outlet 11a may be located at each end of the base 11.

[0088] In some embodiments, referring to FIG. 1 and FIG. 11 , the base 11 structure further includes a spiral channel 11 b, through which air-cooling medium or liquid-cooling medium is introduced to cool the base 11, thereby effectively reducing the temperature of the base 11 and thereby reducing the temperature of the stator 12 and the rotor 13 in the base 11, thereby increasing the heat exchange efficiency of the base 11 and improving the life of the centrifugal air compressor.

[0089] In order to improve the airtightness and prevent gas leakage due to poor sealing during cooling, thereby reducing the cooling efficiency. In some embodiments, please refer to Figure 1, the centrifugal air compressor also includes a sealing assembly 40 to perform multi-stage sealing on the centrifugal air compressor. The sealing assembly 40 includes a first sealing structure 41, a second sealing structure 42, and a third sealing structure 43. The sealing assembly 40 can reduce the risk of gas leakage at each seal, solving problems such as low cooling efficiency, low compression ratio, low overall efficiency, and unqualified airtightness test of the centrifugal air compressor system.

[0090] The first sealing structure 41 is configured as a shaft seal and is disposed between the end cover 16 and the rotor 13, and between the thrust plate 32 and the end cover 16. The first sealing structure 41 isolates the internal cavity of the motor assembly 10 from the compression chamber 20a of the compression assembly 20, thereby ensuring a stable compressed air flow in the compression chamber 20a.

[0091] The first sealing structure 41 is a grate seal. Specifically, both the first end cap 161 and the second end cap 162 are provided with a grate structure. The single-sided gap between the grate structure and the rotor 13 is 0.25 mm, that is, the gap between the rotor 13 and all the grate teeth on the inner circumference of the end cap is 0.25 mm, meeting the sealing requirements.

[0092] The second sealing structure 42 is provided between the impeller 21 and the end cover 16 and is configured as a grate seal structure to reduce the back pressure on the back of the impeller 21 , lower the axial force of the rotor 13 , and prevent the thrust bearing 33 from being subjected to excessive force and causing failure.

[0093] A third sealing structure 43 is provided between the end cover 16 and the volute 22 on both sides. For example, the third sealing structure 43 is a sealing ring. A sealing groove is provided on the end cover 16 or the volute 22, and a sealing ring is placed in the sealing groove for sealing to avoid gaps in the end face fitting due to processing errors.

[0094] In some embodiments, see Section 1. The base 11 includes an inner and outer cylinder, with a spiral passage 11b formed in the inner and / or outer cylinder. The sealing assembly 40 further includes a fourth sealing structure 44, which is secured between the inner and outer cylinders and located on either side of the spiral passage 11b. Specifically, the fourth sealing structure 44 is a sealing ring. A sealing groove is provided in the inner or outer cylinder, and a sealing ring is placed in the groove to provide a seal, thereby preventing the cooling medium from leaking into the base 11.

[0095] Since the rotor 13 is magnetic, if the central axes of the stator 12 and the rotor 13 do not coincide during installation, and the iron cores of the rotor 13 and the stator 12 are not aligned, the rotor 13 and the stator 12 will attract each other, which will affect the stability of the rotation of the rotor 13 and destroy the performance of the radial air bearing 31. The centrifugal air compressor will have large vibrations and noises during operation, which will ultimately affect the overall system stability of the centrifugal air compressor.

[0096] In view of this, embodiments of the present application also provide a centrifugal air compressor assembly method, which can be applied to any of the above-mentioned centrifugal air compressors to improve the alignment and assembly accuracy of the stator and rotor, reduce the risk of wear on the rotor and the foil in the radial air bearing, and improve the coaxiality of the centrifugal air compressor assembly. The installation device includes a slide rail 51, a slider 52 capable of moving along the slide rail 51, a height adjustment seat 54 disposed on the slide rail 51, and a pin device 53 disposed on the height adjustment seat 54. Referring to Figures 12 and 13, the assembly method includes the following steps:

[0097] S10: Mounting the base 11 on a slider 52 that can move along the slide rail 51;

[0098] S20: Connect the bearing seat 15 at one end to the machine base 11 and install the corresponding radial air bearing 31;

[0099] S30: Install the bearing seat 15 at the other end and the corresponding radial air bearing 31 on the rotor 13;

[0100] S40: Using the ejector device 53 to axially position the rotor 13;

[0101] S50: Adjust the height adjustment base 54 supporting the ejector device 53 so that the rotor 13 is aligned with the axis of the base 11;

[0102] S60: Slide the base 11 toward the rotor 13 so that the stator 12 and the rotor 13 on the base 11 are aligned.

[0103] Specifically, the ejector device 53 includes an ejector base 531, an ejector 532, and an ejector post 533. One end of the ejector 532 is fixed to the first height adjustment base 541 via the ejector base 531, and the other end of the ejector 532 abuts against one end of the rotor 13. The other end of the rotor 13 abuts against one end of the ejector post 533. The ejector post 533 passes through the machine base 11, and the other end of the ejector post 533 is fixed to the second height adjustment base 542 via the ejector base 531.

[0104] In some embodiments, referring to FIG. 12 , a push post 533 is connected to the rotor 13 via a guide post 534 . One end of a push pin 532 is fixed to a first height adjustment seat 541 via a push pin seat 531 . The other end of the push pin 532 abuts against one end of the rotor 13 . The other end of the rotor 13 abuts against one end of a guide post 534 . The other end of the guide post 534 abuts against one end of the push post 533 . The push post 533 is disposed through the machine base 11 . The other end of the push post 533 is fixed to a second height adjustment seat 542 via the push pin seat 531 .

[0105] It is understood that the contact structure of the ejector post 533 is identical or similar to that of the ejector pin 532, and both may be conical. The length of the ejector post 533 is greater than the length of the base 11. By extending the length of the ejector post 533 or adding a guide post 534, the base 11 and the rotor 13 are initially spaced apart during the axial positioning of the rotor 13 by the ejector pin 53. This prevents magnetic attraction between the rotor 13 and the stator 12 on the base 11, which could affect the installation of the ejector pin 53 for axial positioning of the rotor 13.

[0106] The present application also provides a centrifugal air compressor detection method, which is applicable to any of the above centrifugal air compressors. Referring to FIG. 14 , the detection method includes the following steps:

[0107] S1: Using a preload torque wrench to detect the preload torque of the rotor 13;

[0108] S2: Predicting the takeoff speed of the rotor 13 based on the preload torque.

[0109] The torque of the installed centrifugal air compressor rotor 13 is tested to preliminarily determine the consistency of the coaxiality of the two radial air bearings 31 and the operating status of the radial air bearings 31, and the takeoff speed of the rotor 13 is predicted. This solves the errors accumulated during the processing and assembly of parts of the rotor, radial air bearings, thrust bearings and other structures, and provides a guarantee for subsequent performance tests of the centrifugal air compressor.

[0110] Taking a specific implementation as an example, part of the installation and testing process of the centrifugal air compressor of the embodiment of the present application is described.

[0111] 1) Install the radial air bearing 31 on the bearing seat 15. Positioning holes are provided in the first and second bearing seats 151, 152, respectively. Positioning pins 35 are installed in the positioning holes of the first and second bearing seats 151, 152, respectively. Align the pin hole of a first retaining ring 341 with the positioning pin 35 and install it on the first bearing seat 151. Align the pin hole of the corresponding radial air bearing 31 with the positioning pin 35 and insert it into the first bearing seat 151. The interference fit between the radial air bearing 31 and the first bearing seat 151 should be within the range of 0.005 to 0.016 mm. Then, install a second retaining ring 342 and fasten it to the end of the first bearing seat 151 away from the step wall 15a with bolts. Align the pin hole of another first retaining ring 341 with the positioning pin 35 and install it on the second bearing seat 152. Align the pin hole of the corresponding radial air bearing 31 with the positioning pin 35 and insert it into the second bearing seat 152. The interference fit between the radial air bearing 31 and the second bearing seat 152 should be controlled within the range of 0.005 to 0.016 mm. Then, install another second retaining ring 342 and tighten it with bolts at the end of the second bearing seat 152 away from the step wall 15a. The radial air bearing 31 and the bearing seat 15 can be assembled by shrink fit or cold fit. For example, the bearing seat 15 can be heated and then inserted into the radial air bearing 31, or the radial air bearing 31 can be frozen and then inserted into the bearing seat 15.

[0112] 2) Mark the rotor 13, thrust plate 32, and impeller 21. Use laser marking on the end faces of the rotor 13, thrust plate 32, and impeller 21 to determine the installation angles of the thrust plate 32 and impeller 21.

[0113] 3) Install the stator 12 on the base 11 . Place a sealing ring in the sealing groove on the inner cylinder or outer cylinder of the base 11 to form a fourth sealing structure 44 , and then install the stator 12 in the base 11 .

[0114] 4) Install the rotor 13 and stator 12 in a centered manner. Secure the base 11 to the slider 52, install the first bearing seat 151 on the rotor 13, and securely connect the second bearing seat 152 to the base 11. Use the ejector seat 531, ejector pin 532, ejector post 533, and guide post 534 to axially position the rotor 13. Adjust the height of the height adjustment seats 54 on both sides to align the rotor 13 and base 11 axes. Slide the base 11 on the slide rail 51 until the cores of the stator 12 and rotor 13 are aligned. Connect the first bearing seat 151 to the base 11.

[0115] 5) Install the thrust bearing 33. The end faces of the second thrust bearing 332 and the second bearing seat 152 each have three pin holes with a diameter of 3 mm. Use the mounting pin 36 to secure the second thrust bearing 332 to the end face of the second bearing seat 152. The mounting pin 36 has an interference fit with the pin holes on the end face of the second bearing seat 152, and the mounting pin 36 has a clearance fit with the pin holes of the second thrust bearing 332. Install the thrust plate 32 on the rotor 13 according to the marked position. The end faces of the first thrust bearing 331 and the second end cover 162 each have three pin holes with a diameter of 3.1 mm. Install the first thrust bearing 331 on the second end cover 162, and the mounting pin 36 has a clearance fit with the pin holes on the end face of the second end cover 162, and the mounting pin 36 has a clearance fit with the pin holes of the first thrust bearing 331.

[0116] 6) Install the end caps 16. Install the first end cap 161 and the second end cap 162 at each end of the rotor 13 and connect them to the corresponding bearing seats 15. The single-side clearance between the grate teeth on the first end cap 161 and the rotor 13, and between the grate teeth on the second end cap 162 and the rotor 13, is 0.25 mm.

[0117] 7) Install the turbine assembly 20. Install the impellers 21 at the marked positions on each end of the rotor 13 using the lock nuts 23. The grate teeth on the end cover 16 are sealed with the grate teeth on the back of the impeller 21 at the corresponding end, forming a second sealing structure 42. Specifically, the grate teeth on the first end cover 161 are sealed with the grate teeth on the back of the impeller 21 at the corresponding end, and the grate teeth on the second end cover 162 are sealed with the grate teeth on the back of the impeller 21 at the corresponding end.

[0118] The first end cover 161 and the second end cover 162 are respectively provided with an annular sealing groove, and a sealing ring is placed in each sealing groove. The volute 22 is fixedly connected to the corresponding bearing seat 15, and the sealing ring is located between the volute 22 and the corresponding end cover 16 to form a third sealing structure 43.

[0119] There is no restriction on the order of the above installation steps, and the order of some steps can be adjusted according to actual conditions.

[0120] After the centrifugal air compressor is assembled, a torque wrench is used to rotate the rotor 13 so that the rotor 13 drives the thrust plate 32 and the impeller 21 to rotate together. The torque of the rotor 13 is tested. Based on the size of the test data, the installation coaxiality and consistency of the radial air bearing 31 and the operating status of the radial air bearing 31 are preliminarily judged, and the take-off speed of the rotor 13 is predicted based on the data results.

[0121] An embodiment of the present application also provides a hydrogen fuel cell, comprising any one of the above-mentioned centrifugal air compressors.

[0122] The centrifugal air compressor, assembly method, detection method and hydrogen fuel cell provided in the embodiments of the present application can solve the problem that the foil is easily pulled out of the radial air bearing when the centrifugal air compressor system is running. At the same time, the assembly accuracy, centering accuracy, assembly convenience, bearing coaxiality and system stability of the centrifugal air compressor are improved. This effectively improves the working reliability and anti-interference performance of the bearing and extends the service life of the bearing. The centrifugal air compressor has high working efficiency, high assembly accuracy, convenient disassembly and assembly, high integration and economic benefits. The detection of the rotor torque after assembly is completed can effectively avoid the problems of damage to the foil of the radial air bearing, too small installation clearance and inconsistent coaxiality due to human assembly errors.

[0123] The various embodiments / implementations provided in this application can be combined with each other without causing any contradiction.

[0124] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A centrifugal air compressor, comprising: a motor assembly including a base, a stator, a rotor, a bearing housing and end covers, wherein the bearing housings are respectively connected to two axial ends of the base, the end covers are connected to the outer sides of the bearing housings at each end, two ends of the rotor respectively pass through the corresponding bearing housings and end covers, and the stator is connected to the base; a compression assembly, the compression assemblies are respectively connected to two axial ends of the motor assembly, each compression assembly includes an impeller and a volute, the impeller is arranged at one end of the rotor and is hermetically connected to the corresponding end cover, the volute covers the outside of the impeller, the volute is respectively connected to the corresponding bearing housing and end cover, and the bearing housing, the end cover and the volute at the corresponding end enclose to form a compression chamber; a bearing assembly including a radial air bearing sleeved on the rotor, a thrust disc, thrust bearings and retaining rings, each bearing housing is connected to the rotor through the radial air bearing, the thrust disc is arranged at one end of the rotor and is located between the corresponding bearing housing and end cover, and the thrust bearings are respectively arranged on two sides of the thrust disc; wherein, retaining rings are respectively arranged at two ends of the radial air bearing, and the retaining rings are connected to the bearing housing for stopping the foil of the radial air bearing.

2. The centrifugal air compressor according to claim 1, wherein the bearing housing has a stepped wall and a stepped cavity, the retaining rings are divided into a first retaining ring and a second retaining ring, and the bearing assembly further includes a positioning pin, and corresponding positioning holes are respectively provided on the stepped wall, the first retaining ring and the radial air bearing; the radial air bearing is located in the stepped cavity, the first retaining ring is located between the stepped wall and the radial air bearing, and the second retaining ring is arranged at the other end of the radial air bearing away from the inner retaining ring; the positioning pin passes through each positioning hole to position the foil slot angle of the radial air bearing.

3. The centrifugal air compressor according to claim 1, wherein the bearing assembly further includes a mounting pin, and corresponding pin holes are respectively provided on the thrust disc, the two thrust bearings, and the bearing housing and end cover at the corresponding end, and the mounting pin passes through each pin hole; the mounting pin is in interference fit with the pin hole on the bearing housing, the mounting pin is in clearance fit with the pin holes on the two thrust bearings, and the mounting pin is in clearance fit with the pin hole on the end cover.

4. The centrifugal air compressor according to claim 1, wherein the end cover is divided into a first end cover at the end away from the thrust disc and a second end cover at the end close to the thrust disc, the bearing housing is divided into a first bearing housing at the end away from the thrust disc and a second bearing housing at the end close to the thrust disc, and the thrust bearing is divided into a first thrust bearing close to the second end cover and a second thrust bearing close to the second bearing housing; The first end cover is provided with a first air inlet hole communicating with the compression chamber at the corresponding end. A first air inlet chamber is formed between the first end cover and the first bearing seat. The first bearing seat is provided with a first ventilation hole. The air in the compression chamber enters the first air inlet chamber through the first air inlet hole, and then enters the machine base through the gap between the corresponding radial air bearing and the rotor to form a first air-cooling flow path. The air in the compression chamber enters the first air inlet chamber through the first air inlet hole, and then enters the machine base through the first ventilation hole to form a second air-cooling flow path. The second bearing seat is provided with a second air inlet hole and a second ventilation hole. A first flow-through channel is formed between the second end cover and the first thrust bearing, and a second flow-through channel is formed between the second bearing seat and the second thrust bearing. Air enters the first flow-through channel through the second air inlet hole, and then enters the machine base through the second flow-through channel and the gap between the corresponding radial air bearing and the rotor to form a third air-cooling flow path. Air enters the first flow-through channel through the second air inlet hole, and then enters the machine base through the second flow-through channel and the second ventilation hole to form a fourth air-cooling flow path.

5. The centrifugal air compressor according to claim 4, wherein the second air inlet hole communicates with the compression chamber at the corresponding end, or the second air inlet hole communicates with the air-cooling flow path in the machine base; and / or, The machine base is provided with an air outlet, and the first air-cooling flow path, the second air-cooling flow path, the third air-cooling flow path and the fourth air-cooling flow path are all communicated with the air outlet.

6. The centrifugal air compressor according to claim 4, wherein the second end cover is provided with a second air inlet chamber inside, a first ring groove in the middle of the side part and a first air inlet through groove on the side part. The second air inlet chamber is communicated with the first air inlet through groove through the first ring groove, and the first air inlet through groove and the first ring groove form the first flow-through channel; and / or, The second bearing seat is provided with a second air inlet through groove penetrating radially inwards to form the second flow-through channel. The second ventilation hole is located inside the second bearing seat and communicates with the second flow-through channel at the rotor.

7. The centrifugal air compressor according to claim 1, wherein the centrifugal air compressor further comprises a sealing assembly, and the sealing assembly comprises: A first sealing structure disposed between the end cover and the rotor and between the thrust disc and the end cover; A second sealing structure disposed between the impeller and the end cover; A third sealing structure disposed between the end cover and the volute.

8. An assembly method of a centrifugal air compressor, which is applied to the centrifugal air compressor according to any one of claims 1 to 7, and the assembly method comprises: Install the machine base provided with the stator on a slider capable of moving along a slide rail; Connect one end of the bearing seat to the machine base and install the corresponding radial air bearing; Install the bearing seat at the other end and the corresponding radial air bearing on the rotor; Axially position the rotor by using a thimble device; Adjust the height adjustment base that supports the thimble device so that the rotor is centered with the machine base in alignment; Slide the machine base in the direction of the rotor so that the stator and the rotor on the machine base are centered.

9. The assembly method according to claim 8, wherein the step of axially positioning the rotor by using the thimble device specifically comprises: In the initial state where the thimble device axially positions the rotor, the machine base and the rotor are spaced apart.

10. A detection method for a centrifugal air compressor, applied to the centrifugal air compressor according to any one of claims 1 to 7, the detection method comprises: Use a pre-tightening torque wrench to detect the pre-tightening torque of the rotor; Predict the take-off speed of the rotor based on the pre-tightening torque.

11. A hydrogen fuel cell, comprising the centrifugal air compressor according to any one of claims 1 to 7.

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