Air floatation centrifugal refrigerant compressor

Abstract

The invention provides a compressor, belongs to the technical field of compressors, and particularly relates to an air floatation centrifugal refrigerant compressor which comprises a motor shell, a motor stator, a compressor rotor part, an air floatation bearing, a volute and a motor end cover. The cooling air supply of the air bearing at the air inlet end of the main shaft comes from the air leaked into the motor shell behind the impeller; the liquid coolant can enter a motor cooling channel on the motor shell and cool a motor stator and a main shaft, and the liquid coolant enters a first cavity in the motor shell after absorbing heat and being gasified; and the cooling supplied air of the air bearing at the air return end of the main shaft comes from the air input into the first cavity from the motor cooling channel and the air from the air inlet end of the main shaft. According to the air flotation centrifugal refrigerant compressor, through the special bearing air supply design and the axial force balance design, the air supply and heat dissipation problems of the air flotation bearing are solved, the balance of the axial force of the rotor part of the compressor is also achieved, and the compressor is simpler and more compact in structure.

Description

Technical Field

[0001] The present application relates to the technical field of impellers, and in particular to an air-floating centrifugal refrigerant compressor. Background Art

[0002] As an indispensable part of modern industry and daily life, the refrigeration and air-conditioning industry has always attracted much attention for its technological development and innovation. As an important component in the refrigeration system, the performance and efficiency of the centrifugal refrigerant compressor are directly related to the operation effect of the entire refrigeration system. In recent years, with the improvement of energy-saving and environmental protection awareness and the continuous advancement of technology, oil-free two-stage compression magnetic suspension and gas suspension compressors have gradually become mainstream products in the market. However, in actual applications, these compressors still have some problems for different application scenarios, such as operating stability, energy efficiency ratio, cost, etc. There is still room for improvement.

[0003] Conventional magnetic levitation or gas levitation usually adopts the form of two-stage compressors. When the compressor is used, an economizer can be configured on the system to improve the operating efficiency of the refrigeration system, which is usually called the method of air replenishment and enthalpy increase. However, the performance improvement brought by air replenishment and enthalpy increase is mainly for the working conditions where the compressor operating pressure is relatively large. For some specific industry applications, such as the oxidation industry, data center cooling, etc., the equipment often operates at a higher evaporation temperature state, the compressor has a low operating pressure ratio, and the configuration of the economizer often becomes redundant. In addition, when operating at a low pressure ratio, the two-stage compressor is not only more difficult to unload, but also has a disadvantage in terms of cost due to the configuration of an additional set of impellers and their components, which also has a negative impact on performance. Under similar specific working conditions, there is still room for improvement in compressors.

[0004] Another reason why conventional magnetic levitation or air levitation compressors use two-stage compression is that by arranging the impellers back to back on the left and right, the aerodynamic axial force of the impellers is balanced to reduce the load on the compressor thrust bearing and ensure the normal operation of the compressor. Summary of the invention

[0005] In view of this, the present application provides an air-floating centrifugal refrigerant compressor, which solves the air supply and heat dissipation problems of the air-floating bearing through a special bearing air supply design and axial force balance design, and also achieves the balance of the axial force of the compressor rotor, making the compressor structure simpler and more compact.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] An air-floating centrifugal refrigerant compressor, comprising:

[0008] A motor housing, a motor stator, a compressor rotor portion, a first air-floating radial bearing, a second air-floating radial bearing, an air-floating thrust bearing, a volute and a motor end cover;

[0009] The motor stator and the compressor rotor are respectively installed inside the motor housing, and the remaining space after the motor stator and the compressor rotor are arranged in the inner cavity space of the motor housing forms a first cavity, and the volute and the motor end cover are respectively arranged at two ends of the motor housing in the axial direction;

[0010] The compressor rotor portion includes a main shaft and an impeller, and the main shaft is rotatably connected to the motor housing through the first air-floating radial bearing and the second air-floating radial bearing;

[0011] The main shaft comprises an air inlet end provided on one side of the first air-floating radial bearing and the air-floating thrust bearing, a middle section provided with a magnetic steel, and an air return end provided on one side of the second air-floating radial bearing, the air inlet end of the main shaft extends out of the axial end of the motor housing, the impeller is provided at the air inlet end of the main shaft and is located between the axial end of the motor housing and the volute;

[0012] The cooling air supply of the air inlet end of the main shaft comes from the gas leaking into the motor housing from the rear of the impeller;

[0013] The motor housing is also provided with a motor cooling channel, the motor cooling channel is communicated with the first cavity, a liquid coolant can enter the motor cooling channel and cool the motor housing, and the liquid coolant enters the first cavity after absorbing heat and vaporizing;

[0014] The cooling air supply at the air return end of the spindle comes from the air input into the first cavity from the motor cooling channel and the air from the air inlet end of the spindle.

[0015] Optionally, it also includes bearing seats, backing plate seals and wheel cover seals;

[0016] The bearing seat is installed at one end of the motor housing, and the first air-floating radial bearing and the second air-floating radial bearing are installed in the bearing seat and the motor housing respectively;

[0017] The back plate seal is arranged at the wheel back of the impeller and is mounted on the bearing seat by screws; the wheel cover seal is arranged at the wheel cover of the impeller and is mounted on the volute by screws.

[0018] Optionally, the compressor rotor portion further includes a thrust plate, a bushing and a lock nut;

[0019] The air inlet end of the main shaft is inserted into the first air-floating radial bearing, the middle section of the main shaft is inserted into the motor stator, and the air outlet end of the main shaft is inserted into the second air-floating radial bearing;

[0020] The thrust plate is arranged at the air inlet end of the main shaft, and the air-floating thrust bearing is installed between the bearing seat and the back plate seal and is respectively located on both sides of the axial direction of the thrust plate;

[0021] The bushing is sleeved on the main shaft, and one axial end of the bushing abuts against the end surface of the thrust plate; the other axial end of the bushing abuts against the wheel back of the impeller; the impeller cover contacts the lock nut and is fixed by the friction force generated by the tensile deformation of the pull rod and the locking torque of the lock nut;

[0022] The back plate seal sleeve is arranged on the bushing, and the radial gap between the back plate seal and the bushing forms an air flow channel.

[0023] Optionally, the air flow channel formed by the radial gap between the bushing and the back plate seal is the intake end cooling channel, and the gas leaked from the back of the impeller flows to the thrust plate, the air-floating thrust bearing and the first air-floating radial bearing through the intake end cooling channel, and then flows to the first cavity in the motor housing.

[0024] Optionally, a cooling liquid inlet interface is provided on the motor housing, and the cooling liquid inlet interface is connected to the spiral motor cooling channel, and the motor cooling channel is connected to the first cavity in the motor housing. Coolant can enter from the cooling liquid inlet interface and vaporize and enter the first cavity when passing through the motor cooling channel.

[0025] Optionally, the radial gap between the motor stator and the compressor rotor forms a main shaft cooling channel. After the cooling gas passing through the thrust plate, the air-floating thrust bearing and the first air-floating radial bearing reaches the first cavity, it is mixed with the cooling gas reaching the first cavity from the motor cooling channel, and then passes through the main shaft cooling channel to cool the middle section of the main shaft provided with magnetic steel.

[0026] Optionally, the air flow channel formed by the radial gap between the second air-floating radial bearing and the main shaft is a return air end cooling channel, and the cooling gas flows from the main shaft cooling channel to the return air end cooling channel to supply air and cool the second air-floating radial bearing.

[0027] Optionally, the cooling gas of the second air-floating radial bearing flows to a second cavity formed by the motor housing and the motor end cover, and is discharged from a return air outlet provided on the motor end cover.

[0028] Optionally, the air supply of the first air-floating radial bearing, the air-floating thrust bearing and the thrust plate is controlled by the pressure difference between the impeller back outlet and the first cavity;

[0029] The air supply volume of the second air-floating radial bearing is controlled by the pressure difference between the return air outlet on the motor end cover and the first cavity.

[0030] Optionally, it also includes an inlet guide vane adjustment mechanism, which is installed on the volute by screws. The inlet guide vane adjustment mechanism includes an actuator and a drive shaft. The actuator can drive the drive shaft to realize the opening and closing of the guide vane blades at the air inlet of the air-floating centrifugal refrigerant compressor and adjust the gas flow.

[0031] The air-floating centrifugal refrigerant compressor provided in the present application adopts a single-stage compressor form, which reduces the number of parts and components, not only improving the operating energy efficiency of the compressor, but also reducing the cost of the compressor, achieving better cost-effectiveness; since air is only taken in at one end, in order to ensure the air supply and cooling of the air-floating radial bearings and air-floating thrust bearings at both ends of the main shaft, a specific bearing air supply structure is designed to solve the heat dissipation problem of the air-floating bearings, making the compressor structure simpler and more compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0033] Figure 1 The general arrangement diagram of the air-floating centrifugal refrigerant compressor of the present application;

[0034] Figure 2 A schematic diagram of a compressor rotor portion of the present application;

[0035] Figure 3 A schematic diagram of a cooling system of the present application.

[0036] exist Figure 1-Figure 3 middle:

[0037] 1. Motor housing; 2. Motor stator; 3. Compressor rotor; 4. First air-floating radial bearing; 5. Second air-floating radial bearing; 6. Bearing seat; 7. Back plate seal; 8. Wheel cover seal; 9. Volute; 10. Motor end cover; 11. Inlet guide vane adjustment mechanism; 12. Second cavity; 13. First cavity; 14. Actuator; 15. Drive shaft;

[0038] 16. Impeller; 17. Main shaft; 18. Thrust plate; 19. Bushing; 20. Lock nut;

[0039] 21. Air intake cooling channel; 22. Motor cooling channel; 23. Air return cooling channel; 24. Spindle cooling channel; 25. Cooling liquid inlet interface; 26. Air return outlet. DETAILED DESCRIPTION

[0040] The present application provides an air-floating centrifugal refrigerant compressor, which solves the air supply and heat dissipation problems of the air-floating bearing through a special bearing air supply design and axial force balance design, and also achieves the balance of the axial force of the compressor rotor, making the compressor structure simpler and more compact.

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] like Figure 1 As shown, the air-floating centrifugal refrigerant compressor provided by the present application comprises:

[0043] Motor housing 1, motor stator 2, compressor rotor part 3, first air-floating radial bearing 4, second air-floating radial bearing 5, air-floating thrust bearing, volute 9 and motor end cover 10;

[0044] The motor stator 2 is heat-fitted into the motor housing 1, and the lead wires of the motor stator 2 are led out to the junction box through the openings on the motor housing 1 and connected to the sealed terminal block;

[0045] The compressor rotor part 3 is rotatably connected to the motor housing 1. Specifically, the compressor rotor part 3 includes a main shaft 17 and an impeller 16. The middle section of the main shaft 17 is inserted into the motor stator 2, and the two ends are rotatably connected to the motor housing 1 through a first air-floating radial bearing 4 and a second air-floating radial bearing 5 installed in the motor housing 1.

[0046] The remaining space after the motor stator 2 and the compressor rotor part 3 are arranged in the inner cavity space of the motor housing 1 forms a first cavity 13, and the volute 9 and the motor end cover 10 are respectively arranged at the two ends of the axial direction of the motor housing 1; the volute 9 is positioned and installed through the end surface of the motor housing 1 to ensure concentricity with the compressor rotor part 3;

[0047] The main shaft 17 includes an air inlet end arranged on one side of the first air-floating radial bearing 4 and the air-floating thrust bearing, a middle section provided with a magnetic steel, and an air return end arranged on one side of the second air-floating radial bearing 5. The air inlet end of the main shaft 17 extends out of the axial end of the motor housing 1. The impeller 16 is arranged at the air inlet end of the main shaft 17 and is located between the axial end of the motor housing 1 and the volute 9.

[0048] The cooling air supply at the air inlet end of the main shaft 17 comes from the gas leaking into the motor housing 1 from the rear of the impeller 16;

[0049] The motor housing 1 is also provided with a motor cooling channel 22, which is connected to the first cavity 13. Liquid coolant can enter the motor cooling channel 22 and cool the motor housing 1. The liquid coolant absorbs heat and vaporizes before entering the first cavity 13.

[0050] The cooling air supply at the return air end of the main shaft 17 comes from the air input into the first cavity 13 from the motor cooling channel 22 and the air from the air inlet end of the main shaft 17 .

[0051] The air-floating centrifugal refrigerant compressor provided by the present application adopts a single-stage compressor form, which reduces the number of parts and components, not only improves the operating energy efficiency of the compressor, but also reduces the cost of the compressor, achieving a better cost-effectiveness ratio; since the main shaft 17 has air intake at only one end, in order to ensure that the air-floating radial bearings and air-floating thrust bearings at both ends of the main shaft 17 are supplied with air and cooled, the present application uses the gas leaked behind the impeller 16 to supply and cool the first air-floating radial bearing 4 and the air-floating thrust bearing at the air supply end, and then inputs liquid coolant through the motor cooling channel 22 on the motor housing 1, on the one hand to achieve heat dissipation of the motor housing 1, and on the other hand to provide cooling gas to the first cavity 13; the cooling gas flowing out of the first air-floating radial bearing 4 and the air-floating thrust bearing is mixed with the cooling gas in the first cavity 13, and together cools and supplies air to the magnetic steel in the middle section of the main shaft 17 and the second air-floating radial bearing 5 at the return air end. Such an air supply and cooling method solves the air supply and heat dissipation problems of the air-floating bearings, and also achieves the balance of the axial force of the compressor rotor part 3, making the compressor structure simpler and more compact.

[0052] like Figure 1 As shown, in a preferred embodiment, it also includes a bearing seat 6, a back plate seal 7 and a wheel cover seal 8;

[0053] The bearing seat 6 is installed at one end of the motor housing 1, the first air-floating radial bearing 4 is installed in the bearing seat 6, and the second air-floating radial bearing 5 is installed in the bearing seat integrally formed with the other end of the motor housing 1; the main shaft 17 of the compressor rotor part 3 passes through the motor stator 2, and is rotatably connected to the motor housing 1 through the support of the first air-floating radial bearing 4 and the second air-floating radial bearing 5;

[0054] In order to control the gas leakage at the back and wheel cover of the impeller 16, a back plate seal 7 and a wheel cover seal 8 are also provided; the back plate seal 7 is provided at the back of the impeller 16 and is mounted on the bearing seat 6 by screws; the wheel cover seal 8 is provided at the wheel cover of the impeller 16 and is mounted on the volute 9 by screws.

[0055] In a preferred embodiment, Figure 2 As shown, the compressor rotor part 3 also includes a thrust plate 18, a bushing 19 and a lock nut 20;

[0056] The air inlet end of the main shaft 17 is inserted into the first air-floating radial bearing 4, the middle section of the main shaft 17 is inserted into the motor stator 2, and the air outlet end of the main shaft 17 is inserted into the second air-floating radial bearing 5;

[0057] The thrust plate 18 is arranged at the air inlet end of the main shaft 17, one end of which is positioned by the shaft shoulder of the main shaft 17, and the other end is pressed by the bushing 19;

[0058] The air-floating thrust bearing is installed between the bearing seat 6 and the back plate seal 7 and is located on both sides of the axial direction of the thrust plate 18. The gap of the air-floating thrust bearing is controlled by adjusting the thickness of the thrust adjustment block so that the air-floating thrust bearing can obtain sufficient cooling gas.

[0059] The impeller 16, the thrust plate 18 and the bushing 19 are all mounted on the main shaft 17 through the center hole, and one axial end of the bushing 19 abuts against the end face of the thrust plate 18; the other axial end of the bushing 19 abuts against the wheel back of the impeller 16; the wheel cover of the impeller 16 contacts with the lock nut 20 and is fixed by the friction force generated by the tensile deformation of the tie rod and the locking torque of the lock nut 20;

[0060] The back plate seal 7 is sleeved on the bushing 19, and the radial gap between the back plate seal 7 and the bushing 19 forms an air flow channel;

[0061] The leaked gas from the back of the impeller 16 passes through the back plate seal 7 and reaches the air flow channel formed by the radial gap between the back plate seal 7 and the bushing 19, thereby supplying air to the first air-floating radial bearing 4.

[0062] In a preferred embodiment, Figure 3 As shown, the air flow channel formed by the radial gap between the bushing 19 and the back plate seal 7 is the air inlet end cooling channel 21. The gas leaked from the back of the impeller 16 flows to the thrust plate 18, the air-floating thrust bearing and the first air-floating radial bearing 4 through the air inlet end cooling channel 21, and then flows to the first cavity 13 in the motor housing 1. In this way, the air supply and cooling of the air inlet end of the main shaft 17 are achieved, that is, air is supplied to the first air-floating radial bearing 4 and the air-floating thrust bearing, and at the same time, the air inlet end of the main shaft 17 and components such as the thrust plate 18, the air-floating thrust bearing and the first air-floating radial bearing 4 are also cooled.

[0063] In a preferred embodiment, Figure 3As shown, a cooling liquid inlet interface 25 is provided on the motor housing 1, and the cooling liquid inlet interface 25 is connected with the spiral motor cooling channel 22, and the motor cooling channel 22 is connected with the first cavity 13 in the motor housing 1. The coolant can enter from the cooling liquid inlet interface 25 and vaporize and enter the first cavity 13 when passing through the motor cooling channel 22. In this way, when the coolant passes through the motor cooling channel 22, it takes away the heat of the motor housing 1, cools the motor housing 1 and the motor stator 2, and at the same time, the coolant absorbs heat and vaporizes into the first cavity 13, and also replenishes the cooling gas in the first cavity 13.

[0064] In a preferred embodiment, Figure 3 As shown, the radial gap between the motor stator 2 and the compressor rotor part 3 forms a main shaft cooling channel 24. After the cooling gas passing through the thrust plate 18, the air-floating thrust bearing and the first air-floating radial bearing 4 reaches the first cavity 13, it is mixed with the cooling gas reaching the first cavity 13 from the motor cooling channel 22, and then passes through the main shaft cooling channel 24 to cool the middle section of the main shaft 17 provided with magnetic steel.

[0065] The cooling effect of the cooling gas passing through the thrust plate 18, the air-floating thrust bearing and the first air-floating radial bearing 4 becomes weaker. At this time, after the cooling gas enters the motor cooling channel 22 from the cooling liquid inlet interface 25 and then enters the first cavity 13 and mixes with them, the cooling effect of the cooling gas is enhanced again, and the middle section of the main shaft 17 provided with magnetic steel can be cooled through the main shaft cooling channel 24.

[0066] In a preferred embodiment, Figure 3 As shown, the air flow channel formed by the radial gap between the second air-floating radial bearing 5 and the main shaft 17 is the return air end cooling channel 23. The cooling gas flows from the main shaft cooling channel 24 to the return air end cooling channel 23, supplies air to and cools the second air-floating radial bearing 5, and then flows to the second cavity 12 formed by the motor housing 1 and the motor end cover 10, and is discharged from the return air outlet 26 arranged on the motor end cover 10.

[0067] After the cooling gas cools the middle section of the main shaft 17 from the main shaft cooling channel 24, it supplies and cools the second air-floating radial bearing 5 through the return air cooling channel 23. The cooling gas flows through the gap of the motor housing 1 to the second cavity 12, is discharged from the return air outlet 26, returns to the cooling system, is cooled and liquefied by the cooling system, and is partially recirculated to the cooling liquid inlet interface 25.

[0068] In a preferred embodiment, the air supply to the first air-floating radial bearing 4, the air-floating thrust bearing and the thrust plate 18 is controlled by the pressure difference between the impeller 16 back outlet and the first cavity 13;

[0069] The air supply to the second air-floating radial bearing 5 is controlled by the pressure difference between the return air outlet 26 on the motor end cover 10 and the first cavity 13; in this way, the gas flow at the air inlet end and the return air end of the main shaft 17 can be adjusted by pressure difference control, thereby achieving the adjustment of the air supply and cooling degree of the first air-floating radial bearing 4, the air-floating thrust bearing and thrust plate 18, and the second air-floating radial bearing 5.

[0070] In a preferred embodiment, it also includes an inlet guide vane adjustment mechanism 11, which is installed on the volute 9 by screws. The inlet guide vane adjustment mechanism 11 includes inlet guide vane blades, an actuator 14 and a drive shaft 15. The actuator 14 can drive the drive shaft 15 to realize the opening and closing of the guide vane blades at the inlet of the air-floating centrifugal refrigerant compressor, thereby realizing the adjustment of the air intake amount at the inlet of the air-floating centrifugal refrigerant compressor, and then controlling the flow of the leaked gas behind the impeller 16.

[0071] The working process of the cooling system of the air-floating centrifugal refrigerant compressor of the present application is as follows Figure 3 As shown: the cooling system includes an air intake cooling channel 21, a motor cooling channel 22, a return air cooling channel 23, a spindle cooling channel 24, a second cavity 12, a first cavity 13, a cooling liquid inlet interface 25 and a return air outlet 26.

[0072] The leaked gas behind the impeller 16 passes through the air inlet cooling channel 21 to reach the first air-floating radial bearing 4, and cools the components at the air inlet end of the main shaft 17, such as the first air-floating radial bearing 4, the thrust plate 18 and the air-floating thrust bearing. The cooled gas reaches the first cavity 13 and mixes with the gas in the motor cooling channel 22, and then passes through the main shaft cooling channel 24 to cool the magnetic steel in the middle section of the main shaft 17. The cooled gas reaches the second cavity 12 through the exhaust hole on the motor housing 1 and the gap between the second air-floating radial bearing 5.

[0073] The mixed gas in the second cavity 12 returns to the cooling system through the return gas outlet 26 , and after being cooled and liquefied, part of the coolant is recirculated to the cooling liquid inlet interface 25 to cool the motor housing 1 and provide supplementary cooling gas for the first cavity 13 .

[0074] The entire cooling system is controlled by the pressure difference between the outlet of the impeller 16 and the first cavity 13 , and between the cooling liquid inlet interface 25 and the return air outlet 26 .

[0075] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0076] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0077] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed or recombined, and these decompositions or recombinations should be regarded as equivalent solutions of the present application.

[0078] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0079] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0080] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. An air-floating centrifugal refrigerant compressor, characterized in that: include: A motor housing (1), a motor stator (2), a compressor rotor (3), a first air-floating radial bearing (4), a second air-floating radial bearing (5), an air-floating thrust bearing, a volute (9) and a motor end cover (10); The motor stator (2) and the compressor rotor part (3) are respectively installed inside the motor housing (1); the remaining space after the motor stator (2) and the compressor rotor part (3) are arranged in the inner cavity space of the motor housing (1) forms a first cavity (13); the volute (9) and the motor end cover (10) are respectively arranged at two ends of the axial direction of the motor housing (1); The compressor rotor part (3) comprises a main shaft (17) and an impeller (16); the main shaft (17) is rotatably connected to the motor housing (1) via the first air-floating radial bearing (4) and the second air-floating radial bearing (5); The main shaft (17) comprises an air inlet end arranged on one side of the first air-floating radial bearing (4) and the air-floating thrust bearing, a middle section provided with a magnetic steel, and an air return end arranged on one side of the second air-floating radial bearing (5), the air inlet end of the main shaft (17) extending out of the axial end of the motor housing (1), and the impeller (16) is arranged at the air inlet end of the main shaft (17) and is located between the end of the motor housing (1) and the volute (9); The cooling air supply at the air inlet end of the main shaft (17) comes from the gas leaking into the motor housing (1) from the rear end of the impeller (16); The motor housing (1) is also provided with a motor cooling channel (22), the motor cooling channel (22) being in communication with the first cavity (13), a liquid coolant being able to enter the motor cooling channel (22) and cool the motor housing (1), and the liquid coolant being able to absorb heat and vaporize and then enter the first cavity (13); The cooling air supply at the air return end of the main shaft (17) comes from the air input into the first cavity (13) from the motor cooling channel (22) and the air from the air inlet end of the main shaft (17).

2. The air-floating centrifugal refrigerant compressor according to claim 1, characterized in that: It also includes a bearing seat (6), a back plate seal (7) and a wheel cover seal (8); the bearing seat (6) is installed at one end of the motor housing (1), and the first air-floating radial bearing (4) and the second air-floating radial bearing (5) are installed in the bearing seat (6) and the motor housing (1) respectively; The back plate seal (7) is arranged at the wheel back of the impeller (16) and is mounted on the bearing seat (6) by means of screws; the wheel cover seal (8) is arranged at the wheel cover of the impeller (16) and is mounted on the volute (9) by means of screws.

3. The air-floating centrifugal refrigerant compressor according to claim 2, characterized in that: The compressor rotor part (3) also includes a thrust plate (18), a bushing (19) and a lock nut (20); The air inlet end of the main shaft (17) is inserted into the first air-floating radial bearing (4), the middle section of the main shaft (17) is inserted into the motor stator (2), and the air outlet end of the main shaft (17) is inserted into the second air-floating radial bearing (5); The thrust plate (18) is arranged at the air inlet end of the main shaft (17), and the air-floating thrust bearing is installed between the bearing seat (6) and the back plate seal (7) and is respectively located on both sides of the axial direction of the thrust plate (18); The bushing (19) is sleeved on the main shaft (17), and one axial end of the bushing (19) abuts against the end surface of the thrust plate (18); the other axial end of the bushing (19) abuts against the wheel back of the impeller (16); the wheel cover of the impeller (16) contacts the lock nut (20) and is fixed by the friction force generated by the tensile deformation of the pull rod and the locking torque of the lock nut (20); The back plate seal (7) is sleeved on the bushing (19), and a radial gap between the back plate seal (7) and the bushing (19) forms an air flow channel.

4. The air-floating centrifugal refrigerant compressor according to claim 3, characterized in that: The air flow channel formed by the radial gap between the bushing (19) and the back plate seal (7) is the air intake cooling channel (21). The gas leaked from the back of the impeller (16) flows through the air intake cooling channel (21) to the thrust plate (18), the air-floating thrust bearing and the first air-floating radial bearing (4), and then flows to the first cavity (13) in the motor housing (1).

5. The air-floating centrifugal refrigerant compressor according to claim 4, characterized in that: The motor housing (1) is provided with a cooling liquid inlet interface (25), the cooling liquid inlet interface (25) is connected to the spiral motor cooling channel (22), the motor cooling channel (22) is connected to the first cavity (13) in the motor housing (1), and the cooling liquid can enter from the cooling liquid inlet interface (25) and vaporize when passing through the motor cooling channel (22) and enter the first cavity (13).

6. The air-floating centrifugal refrigerant compressor according to claim 5, characterized in that: The radial gap between the motor stator (2) and the compressor rotor part (3) forms a main shaft cooling channel (24). After the cooling gas passes through the thrust plate (18), the air-floating thrust bearing and the first air-floating radial bearing (4) and reaches the first cavity (13), it is mixed with the cooling gas reaching the first cavity (13) from the motor cooling channel (22), and then passes through the main shaft cooling channel (24) to cool the middle section of the main shaft (17) provided with magnetic steel.

7. The air-floating centrifugal refrigerant compressor according to claim 6, characterized in that: The air flow channel formed by the radial gap between the second air-floating radial bearing (5) and the main shaft (17) is the return air end cooling channel (23), and the cooling gas flows from the main shaft cooling channel (24) to the return air end cooling channel (23) to supply air to and cool the second air-floating radial bearing (5).

8. The air-floating centrifugal refrigerant compressor according to claim 7, characterized in that: The cooling gas of the second air-floating radial bearing (5) flows into a second cavity (12) formed by the motor housing (1) and the motor end cover (10), and is discharged from a return air outlet (26) provided on the motor end cover (10).

9. The air-floating centrifugal refrigerant compressor according to claim 8, characterized in that: The air supply of the first air-floating radial bearing (4), the air-floating thrust bearing and the thrust plate (18) is controlled by the pressure difference between the impeller (16) wheel back outlet and the first cavity (13); The air supply volume of the second air-floating radial bearing (5) is controlled by the pressure difference between the return air outlet (26) on the motor end cover (10) and the first cavity (13).

10. The air-floating centrifugal refrigerant compressor according to claim 1, characterized in that: It also includes an inlet guide vane adjustment mechanism (11), which is mounted on the volute (9) by means of screws. The inlet guide vane adjustment mechanism (11) includes an actuator (14) and a drive shaft (15). The actuator (14) can drive the drive shaft (15) to realize the opening and closing of the guide vane blades at the air inlet of the air-floating centrifugal refrigerant compressor and adjust the gas flow.

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