Rotating shaft assembly, motor, compressor and air conditioner

Abstract

The application discloses a rotating shaft assembly, a motor, a compressor and an air conditioner. The rotating shaft assembly comprises a rotating shaft and an axial composite bearing. The rotating shaft comprises a thrust disc. The axial composite bearing comprises a magnetic suspension bearing and a backup bearing which are sleeved outside the rotating shaft. The backup bearing is a non-magnetic suspension bearing. The magnetic suspension bearing and the backup bearing are arranged to selectively cooperate with the thrust disc to provide axial thrust. Among the backup bearing and the magnetic suspension bearing located on the same side of the thrust disc, the axial gap S1 between the backup bearing and the thrust disc is smaller than the axial gap S2 between the magnetic suspension bearing and the thrust disc. The rotating shaft is supported by the axial composite bearing. The magnetic suspension bearing in the axial composite bearing has a large bearing capacity, and the non-magnetic suspension bearing is arranged as a backup bearing to function when the magnetic suspension bearing fails, so as to provide sufficient axial thrust for the rotating shaft.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a rotating shaft assembly, an electric machine, a compressor and an air conditioner. BACKGROUND

[0002] Oil-free bearings have been rapidly developed in the food, petrochemical and refrigeration industries in the past decade because they can eliminate the lubrication system for rotating machinery, improve energy conversion efficiency, reduce additional pollution during operation, reduce equipment operation failure and improve reliability. Among them, gas-suspended bearings (also known as air bearings) and magnetic-suspended bearings have attracted further attention because they do not contact the rotating shaft, the friction between the bearing and the shaft is small compared to contact bearings, and the energy-saving effect is particularly obvious in combination with high-speed drive motor technology.

[0003] In a magnetic-suspended bearing, coils are arranged on the motor shaft and the bearing, and a controller communicates with the magnetic bearing and supplies power to the coils to provide a magnetic field that rotates to support the motor shaft. The magnetic force causes the shaft to be suspended in the middle of the bearing. The advantage of the magnetic-suspended bearing is that it has a large carrying capacity and can be widely used in various working media of compressors, and the gap between the shaft and the bearing is generally 100-300 microns; the disadvantage is that the control accuracy of the magnetic bearing is high, the control system is complex, the cost is high, and when used as a radial bearing, the gap between the shaft and the bearing is large, resulting in a large gap between the pneumatic compression component and the fixed cavity, high leakage rate and low pneumatic efficiency.

[0004] Gas-suspended bearings are further divided into dynamic pressure gas-suspended bearings and static pressure gas-suspended bearings. The material of the static pressure gas-suspended bearing is generally a porous medium, which uses a separate gas supply system to supply gas to the bearing. The static pressure gas-suspended bearing has a large carrying capacity and low cost, but requires an auxiliary gas supply system, and the gap between the shaft and the bearing is small, generally in the order of 10-100 nanometers, which requires high manufacturing precision and quality, and the porous medium is prone to blockage, resulting in high cost. The static pressure gas-suspended bearing is greatly affected by the characteristics of the working medium (such as pressure and density).

[0005] Dynamic pressure gas-suspended bearings usually use special foil designs in the bearing to generate a stable air layer between the shaft and the bearing during high-speed rotation, which supports the shaft and makes the shaft float. The gap between the dynamic pressure gas-suspended bearing and the shaft is in the order of 10-100 microns, and no auxiliary gas supply system is required, resulting in lower manufacturing cost. However, the unit surface carrying capacity of the dynamic pressure gas-suspended bearing is small, especially the axial thrust bearing, which cannot provide sufficient support when the pressure difference between the inlet and outlet of the compressor is large. SUMMARY

[0006] The main purpose of the embodiment of the present application is to provide a rotating shaft assembly, the rotating shaft of which is supported by an axial composite bearing, the magnetic suspension bearing in the axial composite bearing has a large bearing capacity, and a non-magnetic suspension bearing is arranged as a backup bearing to function when the magnetic suspension bearing fails, so as to provide sufficient axial thrust for the rotating shaft.

[0007] To achieve the above-mentioned purpose, the technical scheme of the embodiment of the present application is as follows:

[0008] A rotating shaft assembly comprises:

[0009] A rotating shaft comprising a thrust disc; and

[0010] An axial composite bearing comprising a magnetic suspension bearing and a backup bearing sleeved on the rotating shaft, the backup bearing being a non-magnetic suspension bearing, the magnetic suspension bearing and the backup bearing being arranged to selectively cooperate with the thrust disc to provide axial thrust;

[0011] Among the backup bearing and the magnetic suspension bearing located on the same side of the thrust disc, the axial gap S1 between the backup bearing and the thrust disc is smaller than the axial gap S2 between the magnetic suspension bearing and the thrust disc.

[0012] In some exemplary embodiments, S1 is 0.05-0.1 mm smaller than S2.

[0013] In some exemplary embodiments, S2 is 0.1-0.3 mm.

[0014] In some exemplary embodiments, the rotating shaft assembly further comprises:

[0015] A position sensor arranged to detect the axial position of the thrust disc relative to the axial composite bearing, so as to control the operation of the magnetic suspension bearing according to the detection result.

[0016] In some exemplary embodiments, the position sensor is installed on the side of the magnetic suspension bearing close to the thrust disc, or installed on the side of the backup bearing close to the thrust disc.

[0017] In some exemplary embodiments, the magnetic suspension bearing comprises two arranged in pairs, and the two magnetic suspension bearings are respectively located on the two sides of the thrust disc.

[0018] The position sensor is arranged in plurality and respectively installed on the two magnetic suspension bearings.

[0019] In some exemplary embodiments, the position sensor is an eddy current sensor.

[0020] In some exemplary embodiments, one of the magnetic suspension bearing and the backup bearing is sleeved on the other.

[0021] In some example embodiments, the magnetic suspension bearings are arranged in pairs, and two of the magnetic suspension bearings are respectively arranged on two sides of the thrust disc.

[0022] The backup bearings are arranged in pairs, and two of the backup bearings are respectively arranged on two sides of the thrust disc, and the two magnetic suspension bearings are respectively sleeved outside the two backup bearings.

[0023] In some example embodiments, the backup bearings are oil-free bearings.

[0024] In some example embodiments, the shaft assembly further comprises:

[0025] A radial air bearing is sleeved outside the shaft.

[0026] In some example embodiments, the radial air bearings are dynamic pressure air bearings, and two of the radial air bearings are respectively sleeved on two sides of the shaft, and the axial composite bearing is arranged between the two radial air bearings.

[0027] A motor comprises:

[0028] A housing is provided with a mounting cavity.

[0029] The shaft assembly of any one of the above embodiments is mounted in the mounting cavity.

[0030] A rotor is mounted on the shaft of the shaft assembly; and

[0031] A stator is sleeved outside the rotor.

[0032] In some example embodiments, the housing is provided with a cooling liquid inlet, a cooling liquid outlet and a cooling liquid flow channel, the cooling liquid flow channel is arranged on the inner wall surface of the mounting cavity, and the two ends thereof are respectively communicated with the cooling liquid inlet and the cooling liquid outlet.

[0033] In some example embodiments, the cooling liquid inlet is arranged on the upper part of the housing, the cooling liquid outlet is arranged on the lower part of the housing, and the cooling liquid flow channel is a spiral flow channel.

[0034] A compressor comprises the motor of any one of the above embodiments.

[0035] In some example embodiments, the compressor further comprises at least one impeller, and the at least one impeller is mounted on one side or both sides of the shaft of the motor.

[0036] An air conditioner comprises the compressor of any one of the above embodiments.

[0037] In this embodiment of the invention, the rotating shaft assembly is supported by an axial composite bearing, which includes a spare bearing formed by a magnetic levitation bearing and a non-magnetic levitation bearing. During normal operation, the magnetic levitation bearing cooperates with the thrust plate to apply axial thrust to the rotating shaft, at which point the spare bearing is inactive. Using the magnetic levitation bearing as the axial thrust bearing provides greater load capacity and flexible adjustment, enabling it to withstand the large load generated by the compressor at high pressure ratios. The spare bearing is used to function when the magnetic levitation bearing fails (e.g., power failure or other malfunctions) to facilitate the lowering of the rotating shaft in emergency situations. In this case, the spare bearing cooperates with the thrust plate to apply axial thrust to the rotating shaft. Furthermore, for the spare bearing and the magnetic levitation bearing located on the same side of the thrust plate, the axial clearance S1 between the spare bearing and the thrust plate is smaller than the axial clearance S2 between the magnetic levitation bearing and the thrust plate. Therefore, when the magnetic levitation bearing fails and the spare bearing functions, the spare bearing contacts the thrust plate first, preventing contact and wear between the magnetic levitation bearing and the thrust plate, thus improving the service life of the magnetic levitation bearing. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a motor according to an embodiment of the present invention;

[0040] Figure 2 for Figure 1 A cross-sectional view of the motor shown;

[0041] Figure 3 for Figure 1 The diagram shows the structure of the axial composite bearing of the motor.

[0042] Figure 4 for Figure 1 The diagram shows the structure of the radial air bearing of the motor.

[0043] Figure 5 This is a schematic diagram of the structure of the motor according to another embodiment of the present invention;

[0044] Figure 6 for Figure 5 The diagram shows a cross-sectional view of the motor.

[0045] The attached figures are labeled as follows:

[0046] 1-Shaft, 11-Thrust disc, 2-Axial composite bearing, 21a, 21b-Magnetic levitation bearing, 213-Wire, 22a, 22b-Spare bearing, 3-Position sensor, 4a, 4b-Radial air bearing, 41-Bearing housing, 42-Wave foil, 43-Top foil, 44-Fixing pin, 5-Impeller, 6-Housing, 61-Mounting cavity, 62-Coolant inlet, 63-Coolant outlet, 64-Coolant flow channel, 7-Rotor, 8-Stator, 9a, 9b-Radial bearing housing.

[0047] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0049] like Figures 1-6 As shown, an embodiment of the present invention provides a rotating shaft assembly that can be applied to a motor or other products. A motor including the rotating shaft assembly can be applied to a compressor.

[0050] The shaft assembly includes a shaft 1 and an axial composite bearing 2, which can be sleeved on the shaft 1 and can provide axial thrust to the shaft 1.

[0051] The rotating shaft 1 includes a thrust disk 11, which can cooperate with an axial compound bearing 2 so that the axial compound bearing 2 provides axial thrust to the rotating shaft 1 through the thrust disk 11.

[0052] The axial composite bearing 2 includes a magnetic levitation bearing and a spare bearing sleeved outside the rotating shaft 1. The spare bearing is a non-magnetic levitation bearing. The magnetic levitation bearing and the spare bearing are configured to cooperate with the thrust disk 11 to provide axial thrust force, and the axial clearance S1 between the spare bearing and the thrust disk 11 is smaller than the axial clearance S2 between the magnetic levitation bearing and the thrust disk 11.

[0053] exist Figure 3 In the illustrated embodiment, the magnetic levitation bearings may include two pairs, namely magnetic levitation bearing 21a and magnetic levitation bearing 21b, which are located on opposite sides of the thrust disk 11. Magnetic levitation bearings 21a and 21b are connected to a power source via wires 213 to supply power to them.

[0054] Corresponding to the two magnetic suspension bearings 21a, 21b arranged in pairs, the standby bearings can include two arranged in pairs, standby bearing 22a and standby bearing 22b, standby bearing 22a and standby bearing 22a, 22b are respectively located on both sides of the thrust disc 11. Among them, standby bearing 22a and magnetic suspension bearing 21a are located on one side of the thrust disc 11, and the axial gap S1 between the standby bearing 22a and the thrust disc 11 is smaller than the axial gap S2 between the magnetic suspension bearing 21a and the thrust disc 11; magnetic suspension bearing 21b and standby bearing 22b are located on the other side of the thrust disc 11, and the axial gap S1 between the standby bearing 22b and the thrust disc 11 is smaller than the axial gap S2 between the magnetic suspension bearing 21b and the thrust disc 11.

[0055] In the shaft assembly, the shaft 1 is supported by the axial composite bearing 2, the axial composite bearing 2 includes the magnetic suspension bearings 21a, 21b and the standby bearings 22a, 22b formed by the non-magnetic suspension bearings, in normal working, the coils of the magnetic suspension bearings 21a, 21b can be powered to generate a magnetic field, and an axial thrust force is applied to the thrust disc 11 (which can be provided with a magnetic member), thereby realizing the application of an axial thrust force to the shaft 1, at this time, the standby bearings 22a, 22b do not work, the magnetic suspension bearings 21a, 21b are used as axial thrust bearings, the carrying capacity is larger and the adjustment is flexible, when the shaft assembly is applied to a compressor, it can withstand the large carrying capacity generated by the compressor under large pressure ratio; the standby bearings 22a, 22b are used to work when the magnetic suspension bearings 21a, 21b fail (such as power failure or other failures), to lower the shaft 1 in emergency failure, at this time, the standby bearings 22a, 22b can cooperate with the thrust disc 11 to apply an axial thrust force to the shaft 1; in addition, for the standby bearing 22a and the magnetic suspension bearing 21a, and the standby bearing 22b and the magnetic suspension bearing 21b arranged on the same side of the thrust disc 11, the axial gap S1 between the standby bearing 22a and the thrust disc 11 is smaller than the axial gap S2 between the magnetic suspension bearing 21a and the thrust disc 11, and the axial gap S1 between the standby bearing 22b and the thrust disc 11 is smaller than the axial gap S2 between the magnetic suspension bearing 21b and the thrust disc 11, therefore, when the magnetic suspension bearings 21a, 21b fail and the standby bearings 22a, 22b work, the standby bearings 22a, 22b first contact the thrust disc 11, avoiding the magnetic suspension bearings 21a, 21b from contacting and wearing the thrust disc 11, and improving the service life of the magnetic suspension bearings 21a, 21b.

[0056] The axial composite bearing 2 includes two magnetic suspension bearings 21a, 21b arranged in pairs, and the magnetic suspension bearing 21a and the magnetic suspension bearing 21b are respectively located on both sides of the thrust disc 11, and the magnetic suspension bearing 21a and the magnetic suspension bearing 21b cooperate to apply a bidirectional axial thrust force to the thrust disc 11.

[0057] The axial composite bearing 2 comprises two standby bearings 22a and 22b arranged in pairs, and the standby bearing 22a and the standby bearing 22b are respectively located on both sides of the thrust disc 11, and the standby bearing 22a and the standby bearing 22b cooperate to apply bidirectional axial thrust force to the thrust disc 11.

[0058] In some example embodiments, S1 is 0.05mm-0.1mm less than S2, such as: S1 can be 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, etc. less than S2.

[0059] The axial gap S1 between the standby bearing 22a and the thrust disc 11 is 0.05mm-0.1mm less than the axial gap S2 between the magnetic suspension bearing 21a and the thrust disc 11, and the axial gap S1 between the standby bearing 22b and the thrust disc 11 is 0.05mm-0.1mm less than the axial gap S2 between the magnetic suspension bearing 21b and the thrust disc 11, which avoids that the difference between S1 and S2 is too large, resulting in obvious axial shaking of the rotating shaft 1 when the magnetic suspension bearing 21a, 21b is switched to the standby bearing 22a, 22b to provide axial thrust force.

[0060] Of course, the difference between S1 and S2 is not limited to the above range, and can also be adjusted according to actual needs.

[0061] In some example embodiments, S2 is 0.1mm-0.3mm, such as: S2 can be 0.1mm, 0.13mm, 0.15mm, 0.18mm, 0.2mm, 0.23mm, 0.25mm, 0.28mm, 0.3mm, etc. Correspondingly, S1 can be 0.05mm-0.25mm, such as: S1 can be 0.05mm, 0.08mm, 0.1mm, 0.13mm, 0.15mm, 0.18mm, 0.2mm, 0.23mm, 0.25mm, etc.

[0062] According to the control accuracy of the magnetic suspension bearing 21a, 21b, the gap S2 between the magnetic suspension bearing 21a, 21b and the thrust disc 11 can be controlled to be 0.1mm-0.3mm, so that the magnetic suspension bearing 21a, 21b provides axial thrust force for the rotating shaft 1; and according to the difference between S1 and S2, S1 is set to 0.05mm-0.25mm.

[0063] Of course, the values of S1 and S2 are not limited to the above range, and can also be adjusted according to actual needs.

[0064] In some example embodiments, such as Figure 3As shown, the rotating shaft assembly further comprises a position sensor 3 arranged to detect the axial position of the thrust disc 11 relative to the axial composite bearing 2, and to control the operation of the magnetic suspension bearings 21a, 21b according to the detection result.

[0065] The position sensor 3 can detect the axial position of the thrust disc 11 relative to the axial composite bearing 2, for example, the position sensor 3 can detect the axial position of the thrust disc 11 relative to the magnetic suspension bearings 21a, 21b, or detect the axial position of the thrust disc 11 relative to the backup bearings 22a, 22b; the controller can control the operation of the magnetic suspension bearings 21a, 21b according to the position information detected by the position sensor 3, for example, control the current size in the coils of the magnetic suspension bearings 21a, 21b, so that the thrust disc 11 does not contact the backup bearings 22a, 22b when the magnetic suspension bearings 21a, 21b are working, avoiding the backup bearings 22a, 22b from being worn.

[0066] In some example embodiments, as shown, Figure 3 The position sensor 3 can be installed on the side of the magnetic suspension bearing 21a and / or 21b close to the thrust disc 11, or the position sensor 3 can be installed on the side of the backup bearing 22a and / or 22b close to the thrust disc 11.

[0067] The position sensor 3 can be installed on the side of the magnetic suspension bearing 21a and / or 21b close to the thrust disc 11, so as to detect the axial position of the thrust disc 11 relative to the magnetic suspension bearings 21a, 21b, or the position sensor 3 can be installed on the side of the backup bearing 22a and / or 22b close to the thrust disc 11, so as to detect the axial position of the thrust disc 11 relative to the backup bearings 22a, 22b.

[0068] In some example embodiments, the position sensor 3 can be provided with multiple, and respectively installed on the magnetic suspension bearing 21a and the magnetic suspension bearing 21b. Among them, the position sensor 3 can be provided with at least three, and the at least three position sensors 3 can be arranged (for example, uniformly arranged) along the circumference of the rotating shaft assembly.

[0069] The axial composite bearing 2 comprises a pair of magnetic suspension bearings 21a, 21b, and the magnetic suspension bearing 21a and the magnetic suspension bearing 21b are both provided with a position sensor 3, which can detect the axial position of the thrust disc 11, so as to control the current size in the magnetic suspension bearing 21a and the magnetic suspension bearing 21b according to the axial position of the thrust disc 11, thereby realizing the accurate control of the bidirectional axial thrust force of the rotating shaft 1, and avoiding the thrust disc 11 from contacting the backup bearings 22a, 22b when the magnetic suspension bearing 21a and the magnetic suspension bearing 21b are working, causing the backup bearings 22a, 22b to be worn.

[0070] In some example embodiments, the position sensor 3 is an eddy current sensor, and the eddy current sensor is installed on the side of the magnetic suspension bearing 21a and the magnetic suspension bearing 21b close to the thrust disc 11.

[0071] The detection electrical signal of the eddy current sensor can change with the change of the axial spacing between the measured thrust disc 11 and the eddy current sensor, and thus the axial position of the thrust disc 11 relative to the axial composite bearing 2 can be known according to the detection signal of the eddy current sensor, and the current size of the magnetic suspension bearing 21a and 21b can be controlled according to the detection electrical signal.

[0072] In some example embodiments, in the axial composite bearing 2, one of the magnetic suspension bearing and the backup bearing is sleeved on the other, i.e., the magnetic suspension bearing can be sleeved outside the backup bearing, or the backup bearing can be sleeved outside the magnetic suspension bearing. Figure 3 As shown in the figure, the two magnetic suspension bearings 21a and 21b are arranged in pairs, the two backup bearings 22a and 22b are arranged in pairs, and the two magnetic suspension bearings 21a and 21b are correspondingly sleeved outside the two backup bearings 22a and 22b, i.e., the magnetic suspension bearing 21a is sleeved outside the backup bearing 22a, and the magnetic suspension bearing 21b is sleeved outside the backup bearing 22a. The thrust disc 11 can pass between the backup bearing 22a and the backup bearing 22b and extend into between the magnetic suspension bearing 21a and the magnetic suspension bearing 21b.

[0073] The magnetic suspension bearings 21a and 21b are respectively sleeved outside the backup bearings 22a and 22b, so that the magnetic suspension bearings 21a and 21b and the backup bearings 22a and 22b can cooperate with the same thrust disc 11 to exert an axial thrust force on the rotating shaft 1, avoiding setting multiple thrust discs 11 to cooperate with the magnetic suspension bearings 21a and 21b and the backup bearings 22a and 22b, which is conducive to simplifying the structure of the rotating shaft 1; in addition, the magnetic suspension bearings 21a and 21b are sleeved outside the backup bearings 22a and 22b, compared with the parallel arrangement of the magnetic suspension bearings 21a and 21b and the backup bearings 22a and 22b along the axial direction of the rotating shaft 1, which is conducive to reducing the axial size occupied by the axial composite bearing 2, and thus is conducive to reducing the axial length of the rotating shaft 1.

[0074] In some example embodiments, the axial spacing between the backup bearing 22a and the backup bearing 22b can be smaller than the axial spacing between the magnetic bearing 21a and the magnetic bearing 21b, and the magnetic bearing 21a and the backup bearing 22a on one side of the thrust disc 11 can be symmetrically arranged with the magnetic bearing 21b and the backup bearing 22b on the other side of the thrust disc 11, so as to achieve that the axial gap S1 between the backup bearing 22a and the thrust disc 11 is smaller than the axial gap S2 between the magnetic bearing 21a and the thrust disc 11, and the axial gap S1 between the backup bearing 22b and the thrust disc 11 is smaller than the axial gap S2 between the magnetic bearing 21b and the thrust disc 11, so that when the magnetic bearings 21a, 21b fail and the backup bearings 22a, 22b work, the backup bearings 22a, 22b first come into contact with the thrust disc 11, avoiding the magnetic bearings 21a, 21b from contacting and wearing the thrust disc 11.

[0075] In some example embodiments, the backup bearings 22a, 22b are oil-free bearings, such as graphite sliding bearings or ceramic rolling bearings.

[0076] The backup bearings 22a, 22b can be oil-free bearings, so as to save the lubrication system, which helps to simplify the structure and improve the energy conversion efficiency. Specifically, the backup bearings 22a, 22b can be sliding bearings (such as graphite sliding bearings processed by special technology) or rolling bearings (such as ceramic rolling bearings) with good self-lubricating performance. Of course, the backup bearings 22a, 22b can also be other oil-free bearings.

[0077] In some example embodiments, the shaft assembly further comprises a radial air bearing, which is sleeved outside the shaft 1. As shown in Figure 2 and Figure 6 The radial air bearing is provided with two radial air bearings 4a and 4b, which are respectively sleeved on both sides of the shaft 1. The radial air bearings 4a, 4b can be dynamic pressure air bearings.

[0078] The dynamic pressure air bearing as the radial bearing has the following advantages:

[0079] 1. Compared with the magnetic bearing as the radial bearing, the dynamic pressure air bearing as the radial bearing has a smaller volume, so that the shaft 1 can be made shorter, stiffer, and have a higher critical speed, thereby making the compressor generate a higher pressure ratio, and the overall structure of the motor is compact.

[0080] 2. High-pressure differential compressors typically operate at higher speeds, and the eccentric force on shaft 1 is proportional to the square of the speed, requiring a further increase in the load-bearing capacity of shaft 1. The characteristic of dynamic pressure air bearings is that their load-bearing capacity also increases at high speeds. This technical characteristic is more suitable for high-pressure differential (or high-pressure ratio) compressors.

[0081] 3. Compared with using magnetic levitation bearings and spare bearings as radial bearings, dynamic pressure air bearings are lower in cost and simpler to manufacture and install.

[0082] 4. The combination of dynamic pressure air bearing and axial composite bearing 2 provides support for the rotating shaft 1, which makes the rotating shaft assembly applicable to a wide range of applications and does not require an additional auxiliary air supply system for static pressure air bearing. It can be used at higher speeds, thereby achieving a large pressure ratio of the compressor.

[0083] In some exemplary embodiments, radial floating bearing 4a and radial floating bearing 4b are respectively sleeved on both sides of rotating shaft 1, and axial composite bearing 2 is located between radial floating bearing 4a and radial floating bearing 4b.

[0084] Two radial air bearings 4a and 4b are respectively arranged on both sides of the rotating shaft 1, and an axial composite bearing 2 is disposed between the two radial air bearings 4a and 4b and close to one side of the rotating shaft 1. The two radial air bearings 4a and 4b can provide support for both sides of the rotating shaft 1 to ensure stable support of the rotating shaft 1.

[0085] In some exemplary embodiments, the hydrodynamic air bearing may be a foil-type gas hydrodynamic bearing, used to support the radial levitation of the rotating shaft 1. The main structure of the foil-type gas hydrodynamic bearing is as follows: Figure 4 As shown, the bearing housing 41 may include a corrugated foil 42, a top foil 43, and a fixing pin 44. The corrugated foil 42 is installed on the inner wall of the bearing housing 41 and is an elastic foil with a special waveform. During operation, the elastic change of the waveform generates a supporting force, providing the bearing with the main stiffness and partial damping. The top foil 43 is a long cylindrical foil that can be disposed on the inner wall of the corrugated foil 42 and can be fixed to the bearing housing 41 (e.g., fixed to the bearing housing 41 by the fixing pin 44). In the radial direction, one side of the top foil 43 overlaps evenly with the tip of each corrugation of the corrugated foil 42, and the friction generated by the contact with the corrugated foil 42 provides another part of the damping for the bearing. The other side of the top foil 43 is clearance-fitted with the rotating shaft 1 to form the air film space required for the hydrodynamic effect.

[0086] The working principle of this foil-type gas dynamic bearing is as follows: under the action of gravity, the rotating shaft 1 becomes eccentric relative to the bearing, forming a wedge-shaped gap with the inner surface of the bearing. When the rotating shaft 1 is rotating at high speed, it continuously brings gas with a certain viscosity into the wedge-shaped gap. The air is compressed to form a high-pressure gas film, which pushes the rotating shaft 1 to achieve radial suspension.

[0087] It should be understood that the radial air floating bearings 4a, 4b can also be static pressure air floating bearings, but the static pressure air floating bearings need an auxiliary air supply system, so a channel needs to be arranged at the position of the bearing seat to introduce air from the outside into the static pressure air floating bearings.

[0088] As shown in Figures 1-2 , Figures 5-6 The motor provided by the embodiments of the present application also includes a housing 6, the shaft assembly provided by any of the embodiments, a rotor 7 and a stator 8.

[0089] The housing 6 is provided with a mounting cavity 61, the shaft assembly can be mounted in the mounting cavity 61, the rotor 7 can be mounted on the shaft 1 of the shaft assembly, and the stator 8 can be sleeved outside the rotor 7.

[0090] In the motor, the housing 6 is provided with the mounting cavity 61, the shaft assembly can be mounted in the mounting cavity 61, and one side or both sides of the shaft 1 can extend out of the housing 6, the axial composite bearing 2 and the radial air floating bearings 4a, 4b can be mounted on the housing 6 to support the shaft 1; the rotor 7 can be mounted on the part of the shaft 1 located in the mounting cavity 61, and the stator 8 is sleeved outside the rotor 7 and located in the mounting cavity 61. When the motor works, the coil of the stator 8 can be electrified to generate a magnetic field, the rotor 7 can rotate under the action of the magnetic field and drive the shaft 1 to rotate, and the axial composite bearing 2 and the radial air floating bearings 4a, 4b can support the shaft 1 and provide radial support force and axial thrust force for the shaft 1.

[0091] In some exemplary embodiments, the motor further includes radial bearing seats 9a, 9b, the radial bearing seats 9a, 9b are respectively mounted on the two sides of the housing 6, and the radial air floating bearings 4a, 4b can be respectively mounted to the radial bearing seats 9a, 9b so that the radial bearing seats 9a, 9b support the radial air floating bearings 4a, 4b.

[0092] In some exemplary embodiments, the motor further includes an axial bearing seat, the axial bearing seat can be mounted on the housing 6, and the axial composite bearing 2 can be mounted on the axial bearing seat so that the axial bearing seat supports the axial composite bearing 2.

[0093] In some exemplary embodiments, as shown in Figures 1-2 , Figures 5-6 As shown in the drawings, the housing 6 is provided with a cooling liquid inlet 62, a cooling liquid outlet 63 and a cooling liquid flow channel 64, the cooling liquid flow channel 64 is arranged on the inner wall surface of the mounting cavity 61, and the two ends of the cooling liquid flow channel 64 are respectively communicated with the cooling liquid inlet 62 and the cooling liquid outlet 63.

[0094] The shell 6 is provided with a cooling liquid inlet 62, a cooling liquid outlet 63 and a cooling liquid flow channel 64. The cooling liquid flow channel 64 is arranged on the inner wall surface of the mounting cavity 61 (i.e. the inner wall surface of the shell 6), so that the cooling liquid flow channel 64 is in communication with the mounting cavity 61, and the two ends of the cooling liquid flow channel 64 are in communication with the cooling liquid inlet 62 and the cooling liquid outlet 63 respectively. Thus, the cooling liquid (such as cooling water or other cooling medium) can flow into the cooling liquid flow channel 64 from the cooling liquid inlet 62, and then cool the components (such as the stator 8) in the mounting cavity 61. The cooled cooling liquid can flow out of the cooling liquid outlet 63. The arrangement of the cooling liquid inlet 62, the cooling liquid outlet 63 and the cooling liquid flow channel 64 avoids excessively high temperature of the motor during operation, and improves the working stability and applicability of the motor.

[0095] In some example embodiments, as shown in Figures 1-2 , Figures 5-6 the cooling liquid inlet 62 is located at the upper portion of the shell 6, and the cooling liquid outlet 63 is located at the lower portion of the shell 6.

[0096] The cooling liquid inlet 62 is located at the upper portion of the shell 6, and the cooling liquid outlet 63 is located at the lower portion of the shell 6. Thus, the cooling liquid entering from the cooling liquid inlet 62 can flow to the cooling liquid flow channel 64 under the action of gravity, and finally flow out of the cooling liquid outlet 63.

[0097] In some example embodiments, the cooling liquid flow channel 64 is a spiral flow channel.

[0098] As shown in Figure 2 and Figure 6 the cooling liquid flow channel 64 is a spiral flow channel arranged on the inner wall surface of the mounting cavity 61, and corresponds to the position of the stator 8, i.e. the spiral flow channel at least partially coincides with the projection of the stator 8 on the plane of the axis of the overrunning shaft 1, so that the cooling liquid flowing into the cooling liquid flow channel 64 can cool the stator 8.

[0099] The motor of the embodiment of the present application, the radial air floating bearing 4a, 4b provides force against the weight of the rotating shaft 1 and the force generated in the radial eccentric operation, the axial composite bearing 2 is composed of the magnetic suspension bearing 21a, 21b and the standby bearing 22a, 22b, and the axial gap between the standby bearing 22a, 22b and the thrust disc 11 is slightly smaller than the axial gap between the magnetic suspension bearing 21a, 21b and the thrust disc 11, wherein the magnetic suspension bearing 21a, 21b provides force against the force generated in the axial direction when the motor is running, the standby bearing 22a, 22b functions when the magnetic suspension bearing 21a, 21b fails and the motor is still in the running state, for the landing of the rotating shaft 1 in the emergency failure case, the standby bearing 22a, 22b can adopt sliding bearings (such as graphite sliding bearings processed by special process) or rolling bearings (such as ceramic rolling bearings) with good self-lubricating performance. In order to better cool the stator 8 of the motor, the inner wall surface of the casing 6 is provided with a cooling liquid flow channel 64, so that the cooling liquid flows in from the cooling liquid inlet 62 at the top of the casing 6, cools the motor stator 8, and then flows out from the cooling liquid outlet 63 at the bottom.

[0100] The embodiment of the present application also provides a compressor comprising the motor provided by any of the above embodiments.

[0101] In some exemplary embodiments, the compressor further comprises at least one impeller 5 mounted on one side or both sides of the rotating shaft 1 of the motor.

[0102] The compressor can have one or more impellers 5, which can be arranged on the same side of the rotating shaft 1 of the motor (such as shown in FIG. 1) as needed, or respectively arranged on both sides of the rotating shaft 1 of the motor (such as shown in FIG. 2). Figure 2 Figure 6

[0103] The embodiment of the present application also provides an air conditioner comprising the compressor provided by any of the above embodiments.

[0104] In summary, in the embodiment of the present application, the magnetic suspension bearing and the standby bearing are used as the axial bearing, the dynamic pressure air floating bearing is used as the radial bearing, and after the technical scheme is used, the main benefits are:

[0105] 1. Compared with the scheme that both the radial and axial directions use the magnetic suspension bearing, the radial dynamic pressure air floating bearing has a smaller volume, which is beneficial to reduce the overall volume of the rotating shaft assembly, and further makes the motor structure including the rotating shaft assembly compact; the magnetic suspension bearing is reduced, the control scheme of the magnetic suspension bearing is simplified, and the difficulty of electromagnetic control is reduced.

[0106] ​​2. The high differential pressure compressor will further increase the speed, and the eccentric force of the rotating shaft is proportional to the square of the rotating speed, so the load bearing force of the rotating shaft is further increased. The dynamic pressure gas bearing has the characteristic that the load bearing force is also increased at high rotating speed. This technical characteristic is more suitable for the large differential pressure (or large pressure ratio) compressor.

[0107] 3. Compared with the magnetic suspension bearing + backup bearing as the radial bearing, the dynamic pressure gas bearing has low cost, simple manufacturing and installation.

[0108] 4. The axial composite bearing using the magnetic suspension bearing + backup bearing has large load bearing force and flexible adjustment.

[0109] 5. The dynamic pressure gas bearing and the axial composite bearing are combined, the application range is wide, and the structure is simplified without the additional auxiliary gas supply system of the static pressure bearing.

[0110] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0111] In addition, the terms "first", "second", and the like are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0112] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0113] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature can mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "over", "above" and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature is "under", "below" and "underneath" the second feature can mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0114] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0115] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A rotating shaft assembly, characterized in that, include: Rotating shaft, including thrust disc; and An axial composite bearing includes a magnetic levitation bearing and a spare bearing sleeved outside the rotating shaft. The spare bearing is a non-magnetic levitation bearing. The magnetic levitation bearing and the spare bearing are configured such that one of them cooperates with the thrust plate to provide axial thrust. The magnetic levitation bearings include two pairs, which are respectively located on both sides of the thrust disk; the spare bearings include two pairs, which are respectively located on both sides of the thrust disk, and the two magnetic levitation bearings are fitted onto the two spare bearings in a one-to-one correspondence. The axial spacing between the two spare bearings is smaller than the axial spacing between the two magnetic levitation bearings, and the magnetic levitation bearing and the spare bearing located on one side of the thrust disk are symmetrically arranged with the magnetic levitation bearing and the spare bearing located on the other side of the thrust disk. In the spare bearing and the magnetic levitation bearing located on the same side of the thrust disk, the axial clearance S1 between the spare bearing and the thrust disk is smaller than the axial clearance S2 between the magnetic levitation bearing and the thrust disk.

2. The rotating shaft assembly according to claim 1, characterized in that, S1 is 0.05mm-0.1mm smaller than S2.

3. The rotating shaft assembly according to claim 1, characterized in that, S2 is 0.1mm-0.3mm.

4. The shaft assembly according to any one of claims 1 to 3, characterized in that, Also includes: A position sensor is configured to detect the axial position of the thrust disk relative to the axial composite bearing, and to control the operation of the magnetic levitation bearing based on the detection result.

5. The rotating shaft assembly according to claim 4, characterized in that, The position sensor is installed on the side of the magnetic levitation bearing near the thrust plate, or on the side of the spare bearing near the thrust plate.

6. The rotating shaft assembly according to claim 4, characterized in that, Multiple position sensors are provided and are respectively installed on the two magnetic levitation bearings.

7. The rotating shaft assembly according to claim 4, characterized in that, The position sensor is an eddy current sensor.

8. The shaft assembly according to any one of claims 1 to 3, characterized in that, The spare bearing is an oil-free bearing.

9. The shaft assembly according to any one of claims 1 to 3, characterized in that, Also includes: A radial air bearing is fitted outside the rotating shaft.

10. The rotating shaft assembly according to claim 9, characterized in that, The radial air bearing is a dynamic pressure air bearing, and two of them are provided. The two radial air bearings are respectively sleeved on both sides of the rotating shaft, and the axial composite bearing is located between the two radial air bearings.

11. An electric motor, characterized in that, include: The casing has a mounting cavity; The rotating shaft assembly according to any one of claims 1 to 10 is installed in the mounting cavity; Rotor, mounted on the shaft of the shaft assembly; and The stator is fitted over the rotor.

12. The motor according to claim 11, characterized in that, The housing is provided with a coolant inlet, a coolant outlet, and a coolant flow channel. The coolant flow channel is located on the inner wall of the mounting cavity, and its two ends are respectively connected to the coolant inlet and the coolant outlet.

13. The motor according to claim 12, characterized in that, The coolant inlet is located at the upper part of the housing, the coolant outlet is located at the lower part of the housing, and the coolant flow channel is a spiral flow channel.

14. A compressor, characterized in that, The motor included in any one of claims 11 to 13.

15. The compressor according to claim 14, characterized in that, It also includes at least one impeller, at least one of the impellers being mounted on one or both sides of the motor shaft.

16. An air conditioner, characterized in that, Includes the compressor described in claim 14 or 15.

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