Opposed two-stage air suspension centrifugal air compressor

Abstract

The utility model relates to an opposed two-stage air suspension centrifugal air compressor which comprises a shell assembly, a rotor assembly, a driving assembly and a cooling system, the shell assembly comprises a first-stage volute, a second-stage volute, a first-stage sealing ring, a second-stage sealing ring, a first-stage radial air bearing base, a motor shell and a motor sleeve; the rotor assembly comprises a motor rotor, a first-stage pull rod, a second-stage pull rod, a thrust disc, a first-stage impeller and a second-stage impeller. The driving assembly comprises a motor stator, a first-stage radial air bearing, a second-stage radial air bearing and an axial air bearing; the cooling system comprises an intercooler and a corresponding connecting pipeline. The centrifugal air compressor can output oil-free compressed air and is efficient and stable in work, low in noise, compact in structure and small in overall size.

Description

TECHNICAL FIELD

[0001] The utility model relates to centrifugal air compressor technical field, concretely relates to a kind of opposed two-stage air suspension centrifugal air compressor. BACKGROUND

[0002] Currently, new energy vehicle industry develops rapidly. Among them, new energy vehicle using hydrogen as fuel is one of the most promising new energy vehicle types. It uses the same electric motor as electric vehicle to drive wheels, but different is that power is not supplied by a large and heavy power battery, but by a hydrogen-fueled cell stack, the emission product is pollution-free and renewable, and is currently recognized as the cleanest new energy vehicle. Among them, air compressor is one of the important components in fuel cell system, and is the key to provide continuous and stable air to fuel cell stack.

[0003] According to relevant research, the power consumed by air compressor accounts for about 15% of the power generated by fuel cell, therefore, it is of great significance to develop high-efficiency air compressor. In addition, fuel cell system has strict requirements for supplied air, such as oil-free, impurity-free, low noise, etc. Therefore, the air compressor using oil sliding bearing in traditional way cannot be applied in fuel cell field. SUMMARY

[0004] The utility model aims at providing a kind of opposed two-stage air suspension centrifugal air compressor, which can output oil-free compressed air, and is efficient, stable and low-noise in operation, and has compact structure and small overall size.

[0005] To achieve the above purpose, the utility model adopts the technical scheme of: a kind of opposed two-stage air suspension centrifugal air compressor, comprising a shell assembly, a rotor assembly, a driving assembly and a cooling system, the shell assembly comprises a primary volute, a secondary volute, a primary seal ring, a secondary seal ring, a primary radial air floating bearing base, a motor shell and a motor sleeve;The rotor assembly comprises a motor rotor, a primary pull rod, a secondary pull rod, a thrust disc, a primary impeller and a secondary impeller;The driving assembly comprises a motor stator, a primary radial air floating bearing, a secondary radial air floating bearing and an axial air floating bearing;The cooling system comprises an intercooler and corresponding connecting pipeline;

[0006] The primary radial air floating bearing base and the secondary seal ring are respectively fixedly connected to the front and rear end faces of the motor shell, the primary seal ring is fixedly connected to the front end face of the primary radial air floating bearing base, the primary volute is located outside the front side of the primary seal ring and is fixedly connected to the front end face of the motor shell, the secondary volute is located outside the rear side of the secondary seal ring and is fixedly connected to the rear end face of the motor shell, and the motor sleeve is fixedly connected to the inner side of the motor shell;

[0007] The motor rotor is located at the center of the centrifugal air compressor, and its front and rear ends are fixedly connected to the first-stage tie rod and the second-stage tie rod, respectively. The thrust plate is located between the first-stage sealing ring and the first-stage radial air bearing base and is installed on the outside of the first-stage tie rod. The first-stage impeller is located inside the first-stage volute and is fixedly connected to the first-stage tie rod. The second-stage impeller is located inside the second-stage volute and is fixedly connected to the second-stage tie rod.

[0008] The motor stator is located between the motor rotor and the motor sleeve and is connected to the inner side of the motor sleeve. The first-stage radial air bearing is installed between the motor rotor and the first-stage radial air bearing base. The second-stage radial air bearing is installed between the motor rotor and the motor housing. Axial air bearings are installed between the thrust plate and the first-stage sealing ring, and between the thrust plate and the first-stage radial air bearing base.

[0009] The intercooler is connected to the exhaust port of the first-stage volute and the air inlet of the second-stage volute via connecting pipes. An air inlet and an air outlet are located on the outer side of the motor housing. The intercooler is also connected to the air inlet and air outlet via connecting pipes. An airflow channel is located inside the motor housing. Air entering the airflow channel from the air inlet is divided into two parts: one part flows to the axial air bearing and the first-stage radial air bearing, and enters the internal cavity of the motor housing through the gap between the first-stage radial air bearing and the motor rotor; the other part flows to the second-stage radial air bearing, and enters the internal cavity of the motor housing through the gap between the second-stage radial air bearing and the motor rotor. After cooling the motor rotor, the two parts of air flow out through the air outlet. A water inlet and a water outlet are also located on the outer side of the motor housing. A spiral water flow channel is formed on the outer peripheral wall of the motor housing. The front and rear ends of the spiral water flow channel pass through the motor housing and connect to the water inlet and water outlet, respectively.

[0010] Furthermore, the primary and secondary impellers are arranged back-to-back to reduce the axial force generated during the operation of the centrifugal air compressor.

[0011] Furthermore, the motor housing is fixedly connected to the primary radial air bearing base, the secondary sealing ring, the primary volute, the secondary volute, and the motor sleeve by screws, and the primary sealing ring is fixedly connected to the primary radial air bearing base by screws.

[0012] Furthermore, the primary radial air bearing base has a first through hole in the middle to allow the front end of the motor rotor to pass through, and a primary radial air bearing insertion groove is formed on the inner side of the first through hole; the primary sealing ring has a second through hole in the middle to allow the primary tie rod to pass through; the rear end face of the motor housing has a third through hole in the middle to allow the rear end of the motor rotor to pass through, and a secondary radial air bearing insertion groove is formed on the inner side of the third through hole; the secondary sealing ring has a fourth through hole in the middle to allow the secondary tie rod to pass through.

[0013] Furthermore, the rotor assembly also includes two locking nuts; the motor rotor is fixedly connected to the primary tie rod and the secondary tie rod by screws, and the thrust disc is fixedly connected to the primary tie rod by an interference fit; the primary tie rod has a raised first stepped portion in the middle and a first threaded portion at the front end; the primary impeller is sleeved on the outside of the primary tie rod and positioned on the first stepped portion, and then connected to the first threaded portion by the locking nut to fix the primary tie rod and the primary impeller; the secondary tie rod has a raised second stepped portion in the middle and a second threaded portion at the rear end; the secondary impeller is sleeved on the outside of the secondary tie rod and positioned on the second stepped portion, and then connected to the second threaded portion by the locking nut to fix the secondary tie rod and the secondary impeller.

[0014] Furthermore, the motor stator and the motor sleeve are fixedly connected by an interference fit; the primary radial air bearing is fixed to the primary radial air bearing base by a key and a bearing retaining ring, and the secondary radial air bearing is fixed to the motor housing by a key and a bearing retaining ring; the two axial air bearings are fixedly connected to the primary sealing ring and the primary radial air bearing base by pins, respectively.

[0015] Furthermore, the front end of the intercooler is connected to the exhaust port of the first-stage volute via a connecting pipe to cool the compressed air discharged from the first stage; the rear end of the intercooler is connected to the air inlet of the second-stage volute via a connecting pipe to provide it with cooled high-pressure air; the middle part of the intercooler is connected to the air inlet connector and the air outlet connector via connecting pipes to provide air to the airflow channel to cool the motor rotor and each air bearing.

[0016] Furthermore, the motor housing has a through-flow channel connecting the front and rear end faces of the housing. The housing flow channel is connected to the air inlet connector. The primary radial air bearing base also has a base flow channel directly opposite the housing flow channel, so that the air entering the housing flow channel from the air inlet connector is divided into two parts, flowing into the gap between the primary sealing ring and the primary radial air bearing base, and the gap between the secondary sealing ring and the motor housing, respectively. The air flowing into the gap between the primary sealing ring and the primary radial air bearing base flows through the axial air bearing, then through the primary radial air bearing between the motor rotor and the primary radial air bearing base, and then enters the internal cavity of the motor housing through the gap between the primary radial air bearing and the motor rotor. The air flowing into the gap between the secondary sealing ring and the motor housing flows through the secondary radial air bearing between the motor rotor and the motor housing, and then enters the internal cavity of the motor housing through the gap between the secondary radial air bearing and the motor rotor. The air outlet connector passes through the motor housing and connects to the internal cavity of the motor housing, so that the air entering the internal cavity of the motor housing cools the motor rotor and then flows out from the air outlet connector.

[0017] Furthermore, the connecting pipe is fixed to the intercooler, the first-stage volute, and the second-stage volute by snap-fit ​​connections; the motor housing is fixed to the air inlet connector, air outlet connector, water inlet connector, and water outlet connector by sealed threaded connections.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. It adopts air bearings, and the output compressed air is free of oil and impurities, which can meet the needs of fuel cells while reducing the later maintenance costs.

[0020] 2. The air bearing has low stiffness, resulting in less vibration and lower noise during the operation of the centrifugal air compressor.

[0021] 3. The impellers are arranged in an opposed manner, which reduces axial force, improves operational stability, and further reduces wear, thereby increasing the service life of the centrifugal air compressor.

[0022] 4. The intermediate cooling system for the primary compressed air significantly improves isentropic efficiency. The design of the cooling system also enhances the operational stability of the air compressor.

[0023] 5. The centrifugal air compressor has a compact overall structure, small size, and low weight.

[0024] Therefore, this utility model has strong practicality and broad application prospects. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of the internal structure of the opposed two-stage air-suspended centrifugal air compressor according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the external overall structure of the opposed two-stage air-suspended centrifugal air compressor according to an embodiment of the present utility model;

[0027] Figure 3 This is a schematic diagram of the airflow channel in an embodiment of this utility model.

[0028] In the diagram: 1-First-stage volute; 2-Motor housing; 3-Motor sleeve; 4-Motor stator; 5-Second-stage volute; 6-Second-stage sealing ring; 7-Second-stage radial air bearing; 8-Second-stage impeller; 9-Locking nut; 10-Second-stage tie rod; 11-Motor rotor; 12-First-stage radial air bearing base; 13-First-stage sealing ring; 14-First-stage impeller; 15-First-stage tie rod; 16-Thrust disc; 17-Axial air bearing; 18-First-stage radial air bearing; 19-Water outlet connector; 20-Air inlet connector; 21-Water inlet connector; 22-Air outlet connector; 23-Connecting pipe; 24-Intercooler; 25-Connecting pipe. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0031] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0032] like Figure 1 , 2 As shown, this embodiment provides a opposed two-stage air-suspended centrifugal air compressor, including a housing assembly, a rotor assembly, a drive assembly, and a cooling system. The housing assembly includes a primary volute 1, a secondary volute 5, a primary sealing ring 13, a secondary sealing ring 6, a primary radial air-bearing base 12, a motor housing 2, and a motor sleeve 3. The housing assembly is the supporting structure of the entire centrifugal air compressor and forms the airflow channel. The rotor assembly includes a motor rotor 11, a primary tie rod 15, a secondary tie rod 10, a thrust disc 16, a primary impeller 14, and a secondary impeller 8. Supported by the housing assembly, the rotor assembly continuously and stably converts electrical energy into mechanical energy, and then converts it into the internal energy of the gas through the impeller's work. The drive assembly includes a motor stator 4, a primary radial air-bearing bearing 18, a secondary radial air-bearing bearing 7, and an axial air-bearing bearing 17. The drive assembly ensures that the rotor assembly can continuously and stably convert power. The cooling system includes an intercooler 24 and corresponding connecting pipes 23 and 25. The cooling system ensures that all components operate at their permissible temperatures throughout the entire process, guaranteeing stable operation of the centrifugal air compressor. The primary and secondary impellers are arranged back-to-back to reduce the axial force generated during operation.

[0033] The primary radial air bearing base 12 and the secondary sealing ring 6 are fixedly connected to the front and rear ends of the motor housing 2, respectively. The primary sealing ring 13 is fixedly connected to the front end of the primary radial air bearing base 12. The primary volute 1 is located on the front side outside the primary sealing ring 13 and is fixedly connected to the front end of the motor housing 2. The secondary volute 5 is located on the rear side outside the secondary sealing ring 6 and is fixedly connected to the rear end of the motor housing 2. The motor sleeve 3 is fixedly connected to the inner side of the motor housing 2.

[0034] The motor rotor 11 is located at the center of the centrifugal air compressor, and its front and rear ends are fixedly connected to the first-stage tie rod 15 and the second-stage tie rod 10, respectively. The thrust plate 16 is located between the first-stage sealing ring 13 and the first-stage radial air bearing base 12 and is installed on the outside of the first-stage tie rod 15. The first-stage impeller 14 is located inside the first-stage volute 1 and is fixedly connected to the first-stage tie rod 15. The second-stage impeller 8 is located inside the second-stage volute 5 and is fixedly connected to the second-stage tie rod 10.

[0035] The motor stator 4 is located between the motor rotor 11 and the motor sleeve 3 and is connected to the inner side of the motor sleeve 3. The primary radial air bearing 18 is installed between the motor rotor 11 and the primary radial air bearing base 12. The secondary radial air bearing 7 is installed between the motor rotor 11 and the motor housing 2. Axial air bearings 17 are installed between the thrust plate 16 and the primary sealing ring 13, and between the thrust plate 16 and the primary radial air bearing base 12.

[0036] The intercooler 24 is connected to the exhaust port of the first-stage volute and the air inlet of the second-stage volute via connecting pipes 23 and 25, respectively. The motor housing 2 is provided with an air inlet connector 20 and an air outlet connector 22 on the outside. The intercooler 24 is also connected to the air inlet connector 20 and the air outlet connector 22 via connecting pipes, respectively. The motor housing 2 has an air flow channel. The air entering the air flow channel from the air inlet connector is divided into two parts. One part flows to the axial air bearing 17 and the first-stage radial air bearing 18, and enters the internal cavity of the motor housing through the gap between the first-stage radial air bearing 18 and the motor rotor 11. The other part flows to the second-stage radial air bearing 7, and enters the internal cavity of the motor housing through the gap between the second-stage radial air bearing 7 and the motor rotor 11. After cooling the motor rotor, the two parts of air flow out from the air outlet connector 22. The motor housing 2 is also provided with an inlet connector 21 and an outlet connector 19 on its outer side. A spiral water flow channel is provided on the outer peripheral wall of the motor sleeve 3. The front and rear ends of the spiral water flow channel pass through the motor housing 2 and are connected to the inlet connector 21 and the outlet connector 19, respectively.

[0037] In this embodiment, the motor housing 2 is fixedly connected to the primary radial air bearing base 12, the secondary sealing ring 6, the primary volute 1, the secondary volute 5, and the motor sleeve 3 by screws. The primary sealing ring 13 is fixedly connected to the primary radial air bearing base 12 by screws.

[0038] In this embodiment, the primary radial air bearing base 12 has a first through hole in its middle to allow the front end of the motor rotor 11 to pass through, and a primary radial air bearing insertion groove is formed on the inner side of the first through hole. The primary sealing ring 13 has a second through hole in its middle to allow the primary tie rod 15 to pass through. The motor housing 2 has a third through hole in its middle rear end face to allow the rear end of the motor rotor 11 to pass through, and a secondary radial air bearing insertion groove is formed on the inner side of the third through hole. The secondary sealing ring 6 has a fourth through hole in its middle to allow the secondary tie rod 10 to pass through.

[0039] In this embodiment, the rotor assembly further includes two locking nuts 9. The motor rotor 11 is fixedly connected to the primary tie rod 15 and the secondary tie rod 10 by screws, and the thrust disc 16 is fixedly connected to the primary tie rod 15 by an interference fit. The primary tie rod 15 has a raised first stepped portion in the middle and a first threaded portion at its front end. The primary impeller 14 is sleeved on the outside of the primary tie rod 15 and positioned on the first stepped portion, and then connected to the first threaded portion by the locking nuts 9 to fix the primary tie rod 15 and the primary impeller 14. The secondary tie rod 10 has a raised second stepped portion in the middle and a second threaded portion at its rear end. The secondary impeller 8 is sleeved on the outside of the secondary tie rod 10 and positioned on the second stepped portion, and then connected to the second threaded portion by the locking nuts 9 to fix the secondary tie rod 10 and the secondary impeller 8.

[0040] In this embodiment, the motor stator 4 and the motor sleeve 3 are fixedly connected by an interference fit. The primary radial air bearing 18 is fixed to the primary radial air bearing base 12 by a key and a bearing retaining ring, and the secondary radial air bearing 7 is fixed to the motor housing 2 by a key and a bearing retaining ring. The two axial air bearings 17 are fixedly connected to the primary sealing ring 13 and the primary radial air bearing base 12 by pins, respectively.

[0041] In this embodiment, the front end of the intercooler 24 is connected to the exhaust port of the first-stage volute via a connecting pipe 23 to cool the compressed air discharged from the first stage. The rear end of the intercooler 24 is connected to the air inlet of the second-stage volute via a connecting pipe 25 to provide it with cooled high-pressure air. The middle part of the intercooler 24 is connected to the air inlet connector 20 and the air outlet connector 22 via connecting pipes to provide air to the airflow channel to cool the motor rotor and each air bearing.

[0042] In this embodiment, the motor housing 2 has a through-flow channel connecting the front and rear end faces of the housing. The housing flow channel is connected to the air inlet connector 20. The primary radial air bearing base 12 also has a base flow channel directly opposite the housing flow channel, so that the air entering the housing flow channel from the air inlet connector 20 is divided into two parts, which flow into the gap between the primary sealing ring 13 and the primary radial air bearing base 12, and the gap between the secondary sealing ring 6 and the motor housing 2, respectively. The air flowing into the gap between the primary sealing ring 13 and the primary radial air bearing base 12 flows through the axial air bearing 17, then through the primary radial air bearing 18 between the motor rotor 11 and the primary radial air bearing base 12, and then enters the internal cavity of the motor housing through the gap between the primary radial air bearing 18 and the motor rotor 11. Air flowing into the gap between the secondary sealing ring 6 and the motor housing 2 flows through the secondary radial air bearing 7 between the motor rotor 11 and the motor housing 2, and then enters the internal cavity of the motor housing through the gap between the secondary radial air bearing 7 and the motor rotor 11. The air outlet 22 passes through the motor housing 2 and communicates with the internal cavity of the motor housing, so that the air entering the internal cavity of the motor housing cools the motor rotor and then flows out from the air outlet 22, completing the cooling process.

[0043] In this embodiment, the connecting pipes 23 and 25 are fixed to the intercooler 24, the primary volute 1, and the secondary volute 5 by snap-fit ​​connections. The motor housing 2 is fixed to the air inlet connector 20, the air outlet connector 22, the water inlet connector 21, and the water outlet connector 19 by sealing threaded connections.

[0044] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its scope of protection shall still fall within the protection scope of this utility model.

Claims

1. A opposed two-stage air-suspended centrifugal air compressor, characterized in that, The system includes a housing assembly, a rotor assembly, a drive assembly, and a cooling system. The housing assembly includes a primary volute, a secondary volute, a primary sealing ring, a secondary sealing ring, a primary radial air bearing base, a motor housing, and a motor sleeve. The rotor assembly includes a motor rotor, a primary tie rod, a secondary tie rod, a thrust disc, a primary impeller, and a secondary impeller. The drive assembly includes a motor stator, a primary radial air bearing, a secondary radial air bearing, and an axial air bearing. The cooling system includes an intercooler and corresponding connecting pipes. The primary radial air bearing base and the secondary sealing ring are fixedly connected to the front and rear ends of the motor housing, respectively. The primary sealing ring is fixedly connected to the front end of the primary radial air bearing base. The primary volute is located outside the front of the primary sealing ring and is fixedly connected to the front end of the motor housing. The secondary volute is located outside the rear of the secondary sealing ring and is fixedly connected to the rear end of the motor housing. The motor sleeve is fixedly connected to the inside of the motor housing. The motor rotor is located at the center of the centrifugal air compressor, and its front and rear ends are fixedly connected to the first-stage tie rod and the second-stage tie rod, respectively. The thrust plate is located between the first-stage sealing ring and the first-stage radial air bearing base and is installed on the outside of the first-stage tie rod. The first-stage impeller is located inside the first-stage volute and is fixedly connected to the first-stage tie rod. The second-stage impeller is located inside the second-stage volute and is fixedly connected to the second-stage tie rod. The motor stator is located between the motor rotor and the motor sleeve and is connected to the inner side of the motor sleeve. The first-stage radial air bearing is installed between the motor rotor and the first-stage radial air bearing base. The second-stage radial air bearing is installed between the motor rotor and the motor housing. Axial air bearings are installed between the thrust plate and the first-stage sealing ring, and between the thrust plate and the first-stage radial air bearing base. The intercooler is connected to the exhaust port of the first-stage volute and the air inlet of the second-stage volute via connecting pipes. An air inlet and an air outlet are located on the outer side of the motor housing. The intercooler is also connected to the air inlet and air outlet via connecting pipes. An airflow channel is located inside the motor housing. Air entering the airflow channel from the air inlet is divided into two parts: one part flows to the axial air bearing and the first-stage radial air bearing, and enters the internal cavity of the motor housing through the gap between the first-stage radial air bearing and the motor rotor; the other part flows to the second-stage radial air bearing, and enters the internal cavity of the motor housing through the gap between the second-stage radial air bearing and the motor rotor. After cooling the motor rotor, the two parts of air flow out through the air outlet. A water inlet and a water outlet are also located on the outer side of the motor housing. A spiral water flow channel is formed on the outer peripheral wall of the motor housing. The front and rear ends of the spiral water flow channel pass through the motor housing and connect to the water inlet and water outlet, respectively.

2. The opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The primary and secondary impellers are arranged back-to-back to reduce the axial force generated during the operation of the centrifugal air compressor.

3. The opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The motor housing is fixedly connected to the primary radial air bearing base, the secondary sealing ring, the primary volute, the secondary volute, and the motor sleeve by screws. The primary sealing ring is fixedly connected to the primary radial air bearing base by screws.

4. The opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The primary radial air bearing base has a first through hole in the middle to allow the front end of the motor rotor to pass through, and a primary radial air bearing insertion groove is formed on the inner side of the first through hole; the primary sealing ring has a second through hole in the middle to allow the primary tie rod to pass through; the rear end face of the motor housing has a third through hole in the middle to allow the rear end of the motor rotor to pass through, and a secondary radial air bearing insertion groove is formed on the inner side of the third through hole; the secondary sealing ring has a fourth through hole in the middle to allow the secondary tie rod to pass through.

5. A opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The rotor assembly also includes two locking nuts; the motor rotor is fixedly connected to the first-stage tie rod and the second-stage tie rod by screws, and the thrust disc is fixedly connected to the first-stage tie rod by an interference fit; the first-stage tie rod has a raised first stepped portion in the middle and a first threaded portion at the front end; the first-stage impeller is sleeved on the outside of the first-stage tie rod and positioned on the first stepped portion, and then connected to the first threaded portion by the locking nut to fix the first-stage tie rod and the first-stage impeller; the second-stage tie rod has a raised second stepped portion in the middle and a second threaded portion at the rear end; the second-stage impeller is sleeved on the outside of the second-stage tie rod and positioned on the second stepped portion, and then connected to the second threaded portion by the locking nut to fix the second-stage tie rod and the second-stage impeller.

6. A opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The motor stator and motor sleeve are fixedly connected by an interference fit; the primary radial air bearing is fixed to the primary radial air bearing base by a key and a bearing retaining ring, and the secondary radial air bearing is fixed to the motor housing by a key and a bearing retaining ring; the two axial air bearings are fixedly connected to the primary sealing ring and the primary radial air bearing base by pins respectively.

7. A opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The front end of the intercooler is connected to the exhaust port of the first-stage volute via a connecting pipe to cool the compressed air discharged from the first stage; the rear end of the intercooler is connected to the air inlet of the second-stage volute via a connecting pipe to provide it with cooled high-pressure air; the middle part of the intercooler is connected to the air inlet connector and the air outlet connector via connecting pipes to provide air to the airflow channel to cool the motor rotor and each air bearing.

8. A opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The motor housing has a through-flow channel connecting the front and rear end faces of the housing. The housing flow channel is connected to the air inlet connector. The primary radial air bearing base also has a base flow channel directly opposite the housing flow channel, so that the air entering the housing flow channel from the air inlet connector is divided into two parts, flowing into the gap between the primary sealing ring and the primary radial air bearing base, and the gap between the secondary sealing ring and the motor housing, respectively. The air flowing into the gap between the primary sealing ring and the primary radial air bearing base flows through the axial air bearing, then through the primary radial air bearing between the motor rotor and the primary radial air bearing base, and then enters the internal cavity of the motor housing through the gap between the primary radial air bearing and the motor rotor. The air flowing into the gap between the secondary sealing ring and the motor housing flows through the secondary radial air bearing between the motor rotor and the motor housing, and then enters the internal cavity of the motor housing through the gap between the secondary radial air bearing and the motor rotor. The air outlet connector passes through the motor housing and connects to the internal cavity of the motor housing, so that the air entering the internal cavity of the motor housing cools the motor rotor and then flows out from the air outlet connector.

9. A opposed two-stage air-suspended centrifugal air compressor according to claim 1, characterized in that, The connecting pipes are fixed to the intercooler, the first-stage volute, and the second-stage volute using snap-fit ​​connections; the motor housing is fixed to the air inlet connector, air outlet connector, water inlet connector, and water outlet connector using sealed threaded connections.

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