Gas bearings, compressors and air conditioning units

Abstract

The present invention relates to a gas bearing, a compressor and an air conditioning unit, wherein the gas bearing comprises: a housing provided with an axial hole for a rotating shaft to pass through; a top foil assembly inserted into the axial hole, the top foil assembly enclosing a cavity for the rotating shaft to pass through, the top foil assembly comprising at least two flat top foils, the at least two top foils being stacked and matched with each other along the radial direction of the axial hole; and at least three corrugated foil assemblies being arranged between the hole wall of the axial hole and the top foil assembly and supporting the top foil assembly; the at least three foil assemblies being opposite each other end to end and forming an annular structure around the outer circumference of the top foil assembly, each of the at least three foil assemblies comprising at least two foils being stacked and matched with each other. The present invention can improve the bearing capacity of the gas bearing.

Description

[0001] The present disclosure is based on and claims priority to an application with CN application number 202010207494.6 and filing date March 23, 2020. The disclosure content of the CN application is hereby introduced as a whole into the present application. Technical Field

[0002] The present invention relates to the technical field of bearings, and in particular to a gas bearing, a compressor and an air conditioning unit. Background Art

[0003] Gas bearings can use gaseous media to suspend the rotating shaft and have a series of advantages such as oil-free, high speed, low vibration, and high temperature resistance.

[0004] The working principle of the relevant foil dynamic pressure gas bearing is: the rotating shaft is eccentric relative to the bearing under the action of gravity, and then forms a wedge-shaped gap with the inner surface of the bearing. When the rotating shaft is rotating at high speed, it continuously brings gas with a certain viscosity into the wedge-shaped gap, and the continuous entry of gas causes the gas film to generate a certain pressure. When the pressure of the gas film is sufficient to balance the load of the rotating shaft, the rotating shaft and the bearing are completely separated. The process of generating the above-mentioned gas film is called the dynamic pressure effect, and the formation speed of the dynamic pressure effect of traditional gas bearings is generally slow, which is not conducive to the application of gas bearings in the field of air conditioning.

[0005] The bearing capacity and damping of the related foil dynamic pressure gas bearings are relatively small, resulting in a high rotor take-off speed, a low critical speed, and excessive vibration, which greatly limits the application of foil dynamic pressure gas bearings in the refrigeration field. Summary of the invention

[0006] Some embodiments of the present invention provide a gas bearing, a compressor and an air conditioning unit capable of improving the bearing capacity.

[0007] Some embodiments of the present invention provide a gas bearing comprising:

[0008] The housing is provided with an axial hole for the rotating shaft to pass through;

[0009] A top foil assembly is inserted into the shaft hole, the top foil assembly encloses a cavity for the shaft to pass through, the top foil assembly includes at least two flat top foils, and the at least two top foils are stacked and matched with each other along the radial direction of the shaft hole; and

[0010] At least three corrugated foil assemblies are arranged between the hole wall of the axial hole and the top foil assembly, and support the top foil assembly; the at least three foil assemblies are opposite to each other end to end and form an annular structure around the outer circumference of the top foil assembly, and each of the at least three foil assemblies includes at least two foils stacked and matched with each other.

[0011] In some embodiments, the at least two matching corrugated foils stacked together are integrally bonded.

[0012] In some embodiments, the corrugated foil includes a corrugated portion and a flat portion. The corrugated portions of two adjacent corrugated foils stacked and matched with each other have a gap between them, and the flat portions are in contact with each other.

[0013] In some embodiments, the gap between the corrugated portions of two adjacent corrugated foils stacked and matched with each other is greater than or equal to 0 and less than or equal to 20 um.

[0014] In some embodiments, the corrugated portions of the two adjacent corrugated foils stacked in a matching manner have different corrugation heights, wherein the corrugated foil with a relatively higher corrugation height has a lower stiffness than the corrugated foil with a relatively lower corrugation height.

[0015] In some embodiments, the bump foil assembly includes a fixed end and a free end, the fixed end of the bump foil assembly is fixedly connected to the housing, and among two adjacent bump foil assemblies, the free end of one bump foil assembly is adjacent to the fixed end of the other bump foil assembly and has a first preset arc distance.

[0016] In some embodiments, the center angle corresponding to the first preset arc distance is θ1, 0<θ1<5°.

[0017] In some embodiments, the bump foil assembly includes a fixed end and a free end, the fixed end of the bump foil assembly is fixedly connected to the housing, and along the rotation direction of the shaft, the fixed end of the bump foil assembly is located upstream of the free end.

[0018] In some embodiments, the housing is provided with a second mounting groove, and the bump foil assembly has the second mounting edge provided in the second mounting groove.

[0019] In some embodiments, the gas bearing also includes a second fastener, and the shell is also provided with a second mounting hole connected to the second mounting groove; the second fastener is passed through the second mounting hole and squeezes the second mounting edge in the second mounting groove to fix the bump foil assembly to the shell.

[0020] In some embodiments, the bump foil assembly is provided with strip-shaped holes, and the strip-shaped holes extend along the circumference of the axial hole.

[0021] In some embodiments, the bump foil assembly is provided with at least two strip-shaped holes, and the at least two strip-shaped holes are arranged at intervals along the axial direction of the shaft hole.

[0022] In some embodiments, among the at least two bump foils stacked and matched with each other, the thickness of the bump foil close to the rotation axis is smaller than the thickness of the bump foil far from the rotation axis.

[0023] In some embodiments, the thickness of the bump foil close to the rotating axis is t2, the thickness of the bump foil away from the rotating axis is t1, and 0≤t1-t2≤0.1 mm.

[0024] In some embodiments, among the at least two top foils, the thickness of the top foil close to the rotation axis is greater than the thickness of the top foil far from the rotation axis.

[0025] In some embodiments, the thickness of the top foil close to the rotating shaft is t4, the thickness of the top foil away from the rotating shaft is t3, and 0≤t4-t3≤0.1 mm.

[0026] In some embodiments, the at least two top foils include a first top foil and a second top foil, and the at least two bump foils include a first bump foil and a second bump foil;

[0027] The second corrugated foil is closer to the hole wall of the axial hole than the first corrugated foil, the thickness of the second corrugated foil is t1, and the thickness of the first corrugated foil is t2;

[0028] The second top foil is closer to the hole wall of the shaft hole than the first top foil, the thickness of the second top foil is t3, and the thickness of the first top foil is t4;

[0029] Among them, t4=2t3=2t2=2t1.

[0030] In some embodiments, the top foil includes a fixed end and a free end. Among two adjacent top foils, a second preset arc distance is provided between the fixed end and the free end of the top foil close to the rotating shaft, and a third preset arc distance is provided between the fixed end and the free end of the top foil away from the rotating shaft, and the third preset arc distance is greater than the second preset arc distance.

[0031] In some embodiments, the housing is provided with a first mounting groove, and the at least two top foils each have a first mounting edge, and each of the first mounting edges is disposed in the first mounting groove.

[0032] In some embodiments, the gas bearing also includes a first fastener, and the shell is also provided with a first mounting hole connected to the first mounting groove, the first fastener is passed through the first mounting hole and squeezes the first mounting edges of the at least two top foils to fix the at least two top foils to the shell.

[0033] In some embodiments, the bump foil assembly includes a fixed end and a free end, the fixed end of the bump foil assembly is fixedly connected to the shell, and among two adjacent bump foil assemblies, the free end of one bump foil assembly is adjacent to the fixed end of the other bump foil assembly and has a first preset arc distance, and the first mounting groove is located within the range of the first preset arc distance.

[0034] In some embodiments, within the range of the first preset arc distance, there is a fourth preset arc distance between the first mounting groove and the free end of one of the bump foil assemblies, and there is a fifth preset arc distance between the first mounting groove and the fixed end of the other bump foil assembly, wherein the fourth preset arc distance is smaller than the fifth preset arc distance.

[0035] In some embodiments, the center angle corresponding to the fourth preset arc distance is θ2, 0<θ2<5°.

[0036] In some embodiments, each of the at least two top foils comprises a fixed end and a free end, wherein a direction from the fixed end to the free end of one top foil is opposite to a direction from the fixed end to the free end of the other top foil.

[0037] In some embodiments, of two adjacent top foils, along the rotation direction of the shaft, the fixed end of the top foil close to the shaft is located upstream of the free end, and the fixed end of the top foil away from the shaft is located downstream of the free end.

[0038] In some embodiments, the fixed ends of the at least two top foils are located at the same assembly position of the housing.

[0039] In some embodiments, the top foil includes a fixed end and a free end, wherein a first inclined section is provided at the free end of the top foil closest to the rotating shaft, and a distance between the first inclined section and the axis of the shaft hole decreases along the rotation direction of the rotating shaft.

[0040] In some embodiments, a second inclined section is provided at a position where the fixed end of the top foil closest to the rotating shaft is located, and along the rotation direction of the rotating shaft, the distance between the second inclined section and the axis center of the shaft hole increases gradually.

[0041] In some embodiments, a top foil adjacent to the top foil closest to the rotating shaft is provided with a third inclined section at the fixed end thereof, and the third inclined section is in contact with the first inclined section.

[0042] In some embodiments, the end position of the free end of the top foil adjacent to the top foil closest to the rotation axis is located at the starting position of the second inclined section.

[0043] In some embodiments, the bump foil assembly corresponding to the position of the first inclined section is provided with a tail wave, the tail wave is configured to support the first inclined section, and the wave height of the tail wave is lower than the wave height of other wave-shaped parts of the bump foil assembly.

[0044] In some embodiments, of the two adjacent top foils, the top foil close to the rotation axis has a stiffness greater than the stiffness of the top foil far from the rotation axis.

[0045] In some embodiments, the at least three corrugated bump foil assemblies include three bump foil assemblies, and the three bump foil assemblies are evenly spaced along the circumference of the hole wall of the axial hole.

[0046] In some embodiments, the wave foil assembly includes a fixed end, a free end, and a plurality of corrugated portions arranged between the fixed end and the free end, the fixed end of the wave foil assembly is fixedly connected to the shell, and at least one free end of the wave foil assembly is provided with a tail wave, and the waveform height of the tail wave is lower than the waveform height of the corrugated portion.

[0047] In some embodiments, the technical solution of the gas bearing is as follows:

[0048] A gas bearing comprises: a shell, the shell is provided with an axial hole; and a foil assembly, the foil assembly is arranged on the hole wall of the axial hole, and the foil assembly surrounds a cavity for a rotating shaft to pass through, the foil assembly has a first inclined section on the side of the hole wall away from the axial hole, the first inclined section includes a first side and a second side arranged along the circumference of the axial hole, and the distance between the first inclined section and the axis of the axial hole decreases from the first side to the second side; wherein, when the rotating shaft is passed through the cavity, a dynamic pressure effect generating area is formed between the first inclined section and the outer periphery of the rotating shaft.

[0049] The technical solution is further described below:

[0050] In some embodiments, the foil assembly includes a bump foil assembly and a top foil, the top foil is inserted into the shaft hole, the bump foil assembly is arranged between the hole wall of the shaft hole and the top foil and supports the top foil, and the top foil has the first inclined section.

[0051] In some embodiments, the first side and the second side are arranged along the direction of normal rotation of the rotating shaft, the top foil further has a second inclined section, the second inclined section and the first inclined section are arranged along the direction of normal rotation of the rotating shaft, and the second inclined section has a third side and a fourth side arranged along the direction of normal rotation of the rotating shaft, the fourth side is butted against the first side, and the distance between the second inclined section and the axis of the shaft hole increases from the third side to the fourth side;

[0052] When the rotating shaft passes through the cavity, an air guide area connected to the dynamic pressure effect generating area is formed between the second inclined section and the outer periphery of the rotating shaft.

[0053] In some embodiments, the foil assembly includes a bump foil assembly and a top foil, the top foil is inserted into the axial hole, the bump foil assembly is arranged between the hole wall of the axial hole and the top foil, and supports the top foil; there are at least two top foils, and at least two top foils are stacked radially along the axial hole.

[0054] In some embodiments, the at least two top foils include a first top foil and a second top foil, the second top foil is attached to the first top foil, and the second top foil is located between the first top foil and the bump foil assembly.

[0055] In some embodiments, the first top foil includes a first fixed end and a first free end, the first top foil extends from the first fixed end to the first free end along the direction of normal rotation of the rotating shaft, and the first fixed end is fixedly connected to the housing, and the second top foil includes a second fixed end and a second free end, the second top foil extends from the second free end to the second fixed end along the direction of normal rotation of the rotating shaft, and the second fixed end is fixedly connected to the housing;

[0056] Or the first top foil includes a first fixed end and a first free end, the first top foil extends from the first free end to the first fixed end along the direction of normal rotation of the rotating shaft, and the first fixed end is fixedly connected to the shell, and the second top foil includes a second fixed end and a second free end, the second top foil extends from the second fixed end to the second free end along the direction of normal rotation of the rotating shaft, and the second fixed end is fixedly connected to the shell.

[0057] In some embodiments, the housing is provided with a first mounting groove, and the top foil has a first mounting edge disposed in the first mounting groove.

[0058] In some embodiments, the gas bearing further comprises a first fastener, the shell further comprises a first mounting hole, the first fastener is passed through the first mounting hole and presses the first mounting edge to fix the top foil to the shell.

[0059] In some embodiments, the bump foil assembly includes at least two bump foil assemblies, the at least two bump foil assemblies are opposite to each other end to end and form a ring structure, and each bump foil assembly is fixedly connected to the housing.

[0060] In some embodiments, the first corrugated foil is provided with first strip-shaped holes, and the first strip-shaped holes are extended along the circumference of the first corrugated foil.

[0061] In some embodiments, there are at least two first strip-shaped holes, and the at least two first strip-shaped holes are arranged at intervals along the axial direction of the bump foil assembly.

[0062] In some embodiments, the bump foil assembly includes at least two bump foils, and the at least two bump foils are stacked along the radial direction of the axial hole.

[0063] In some embodiments, the at least two corrugated foils include a first corrugated foil and a second corrugated foil, the second corrugated foil is attached to the first corrugated foil, and the second corrugated foil is located between the first corrugated foil and a hole wall of the shaft hole.

[0064] In some embodiments, the housing is provided with a second mounting groove, and the bump foil assembly has a second mounting edge arranged in the second mounting groove.

[0065] In some embodiments, the gas bearing further includes a second fastener, the shell further includes a second mounting hole, the second fastener is inserted into the second mounting hole and squeezes the second mounting edge to fix the bump foil assembly to the shell.

[0066] In some embodiments, the second mounting groove is connected to the second mounting hole and forms an assembly position, the shell is provided with at least two assembly positions arranged at circumferential intervals along the axial hole, and the second mounting edge and the second fastener are selectively arranged in the same group of assembly positions.

[0067] In some embodiments, the first side and the second side are arranged along the direction of normal rotation of the rotating shaft, and the side of the foil assembly away from the hole wall of the shaft hole also has a second inclined section, and the second inclined section and the first inclined section are arranged along the direction of normal rotation of the rotating shaft, and the second inclined section has a third side and a fourth side arranged along the direction of normal rotation of the rotating shaft, and the fourth side is connected to the first side, and the distance between the second inclined section and the axis center of the shaft hole increases from the third side to the fourth side. When the rotating shaft is inserted into the cavity, an air guide area connected to the dynamic pressure effect generating area is formed between the second inclined section and the outer periphery of the rotating shaft.

[0068] The compressor scheme is as follows:

[0069] A compressor comprises the gas bearing as described above.

[0070] The scheme of the air conditioning unit is as follows:

[0071] An air conditioning unit comprises the compressor as described above.

[0072] The above gas bearing, compressor and air conditioning unit have at least the following beneficial effects:

[0073] In some embodiments, compared with the solution of a single-layer bump foil assembly, in the present application, the bump foil assembly includes at least two bump foils, and the at least two bump foils are stacked along the radial direction of the axial hole, which can improve the bearing capacity of the gas bearing.

[0074] In some embodiments, because the foil assembly has the first inclined section and there is an obvious wedge-shaped area between the first inclined section and the rotating shaft, the air film can be formed more easily and quickly when the rotating shaft rotates.

[0075] In some embodiments, compared with the single-layer top foil and single-piece bump foil assembly, in the present application, there are at least two top foils, and at least two top foils are stacked radially along the axial hole to improve the damping of the gas bearing.

[0076] In some embodiments, the first fastener and the second fastener are used to fix the top foil and the bump foil assembly respectively, thereby improving the assembly efficiency and reliability of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0078] Figure 1 is a schematic diagram of a three-dimensional structure of a gas bearing in some embodiments of the present invention;

[0079] Figure 2 for Figure 1 A local enlarged structural schematic diagram of the gas bearing at position A shown;

[0080] Figure 3 is a schematic front view of the structure of a gas bearing in some embodiments of the present invention;

[0081] Figure 4 for Figure 3 A schematic diagram of a partially enlarged structure of a gas bearing at position B in some embodiments shown;

[0082] Figure 5 It is a schematic diagram of a partially enlarged structure of a gas bearing in some embodiments of the present invention;

[0083] Figure 6 A schematic diagram of the structure of a first top foil in some embodiments of the present invention;

[0084] Figure 7 A schematic diagram of the structure of a second top foil in some embodiments of the present invention;

[0085] Figure 8 A schematic diagram of the structure of a first corrugated foil or a second corrugated foil in some embodiments of the present invention;

[0086] Fig. 9 for Figure 3 A schematic diagram of a partially enlarged structure of a gas bearing at position B in some other embodiments shown;

[0087] Fig.10 It is a partial enlarged structural schematic diagram of a gas bearing in some other embodiments of the present invention;

[0088] Fig.11 It is a schematic diagram of the structure of the housing in some embodiments of the present invention;

[0089] Fig.12 is a schematic front view of a second top foil in some embodiments of the present invention;

[0090] Fig.13 Schematic diagram of the structure of the first corrugated foil or the second corrugated foil in some other embodiments of the present invention.

[0091] Description of reference numerals:

[0092] 10-gas bearing; 20-rotating shaft;

[0093] 100 - housing; 110 - first mounting slot; 120 - second mounting slot; 130 - first mounting hole; 140 - second mounting hole;

[0094] 200-foil assembly;

[0095] 201 - first mounting edge; 202 - second mounting edge; 203 - dynamic pressure effect generating area; 204 - air guiding area;

[0096] 210-top foil assembly; 2101-top foil;

[0097] 211-first top foil; 2111-first inclined section; 2112-second inclined section; 2113-first sub-mounting edge; 2114-first fixed end; 2115-first free end;

[0098] 212 - second top foil; 2121 - third inclined section; 2122 - second sub-mounting edge; 2123 - second fixed end; 2124 - second free end;

[0099] 220-corrugated foil assembly; 2201-corrugated portion; 2202-flat portion; 2203-corrugated foil; 2204-strip hole; 2205-tail wave;

[0100] 221-first wave foil; 2212-first strip hole; 2213-third sub-mounting edge;

[0101] 222-second wave foil; 2222-second strip hole; 2223-fourth sub-mounting edge;

[0102] 300-first fastener;

[0103] 400 - Second fastener. DETAILED DESCRIPTION

[0104] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0105] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical" - "horizontal" - "left" - "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0106] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0107] The “first” and “second” in the present invention do not represent specific quantities and orders, but are merely used to distinguish names.

[0108] like Figure 1-Figure 3 As shown, an embodiment relates to a gas bearing 10, and the gas bearing 10 is used for a rotating shaft 20 to pass through. When working, the rotating shaft 20 can rotate at a high speed under the action of an electromagnetic field. When the speed reaches a certain value, the gas bearing 10 suspends the rotating shaft 20 through the air film formed by the dynamic pressure effect.

[0109] Specifically, the gas bearing 10 includes a housing 100 and a foil assembly 200. The housing 100 is provided with an axial hole, the foil assembly 200 is arranged on the hole wall of the axial hole, and the foil assembly 200 surrounds a cavity for the rotating shaft 20 to pass through, and when the rotating shaft 20 is passed through the cavity and is coaxially arranged with the axial hole, the rotating shaft 20 and the foil assembly 200 are clearance-matched.

[0110] It should be noted that the shell 100 is a hollow structure, and the shell 100 encloses a hole-shaped space, which is the axial hole, and the hole wall of the axial hole is also the inner wall of the shell 100 .

[0111] like Figure 4As shown, further, the foil assembly 200 has a first inclined section 2111 on one side of the hole wall away from the shaft hole, the first inclined section 2111 includes a first side and a second side arranged along the circumferential direction of the shaft hole, and the distance between the first inclined section 2111 and the axis of the shaft hole decreases from the first side to the second side. When the rotating shaft 20 is inserted into the cavity, a dynamic pressure effect generating area 203 is formed between the first inclined section 2111 and the outer periphery of the rotating shaft 20.

[0112] Specifically, when the rotating shaft 20 is inserted into the cavity, the gap between the first inclined section 2111 and the outer periphery of the rotating shaft 20 gradually decreases from the first side to the second side of the first inclined section 2111, and the gap between the first inclined section 2111 and the rotating shaft 20 is wedge-shaped, so that the rotating shaft 20 generates a dynamic pressure effect when rotating.

[0113] It should be noted that the bearing 10 can generate the dynamic pressure effect under the action of the dynamic pressure effect generating area 203 only when the shaft rotates.

[0114] by Figure 3-4 The gas bearing 10 shown in the figure is explained, the rotating shaft 20 rotates counterclockwise, the first side to the second side of the first inclined section 2111 are arranged in the counterclockwise direction, and the gap between the first inclined section 2111 and the rotating shaft 20 gradually decreases in the counterclockwise direction. In this way, a wedge-shaped dynamic pressure effect generating area 203 is formed between the first inclined section 2111 and the outer periphery of the rotating shaft 20.

[0115] Specifically in this embodiment, the first inclined section 2111 is an inclined straight plate. In other embodiments, the inclined section may also be an arc-shaped plate.

[0116] In the conventional gas bearing 10, the rotating shaft 20 is eccentric relative to the bearing under the action of gravity, thereby forming a wedge-shaped gap with the inner surface of the bearing, and a dynamic pressure effect is formed through the wedge-shaped gap, so that the rotating shaft 20 is suspended. In the gas bearing 10 of the present application, since the foil assembly 200 has the first inclined section 2111, and there is an obvious wedge-shaped area between the first inclined section 2111 and the rotating shaft 20, the rotating shaft 20 can form an air film more easily and quickly when rotating.

[0117] like Figure 2 As shown, in some embodiments, the foil assembly 200 includes a bump foil assembly 220 and a top foil 2101, the top foil 2101 is inserted into the shaft hole, the bump foil assembly 220 is arranged between the hole wall of the shaft hole and the top foil 2101 - and supports the top foil 2101, and the top foil 2101 has a first inclined section 2111.

[0118] Specifically, the foil assembly 200 includes a bump foil assembly 220 and a top foil 2101. The top foil 2101 is inserted into the shaft hole. The foil assembly 200 is arranged between the hole wall of the shaft hole and the top foil 2101 and supports the top foil 2101. The bump foil assembly 220 is an elastic bump foil with a special waveform. When working, the bump foil assembly 220 generates a supporting force through the elastic change of the waveform, providing the main stiffness and partial damping for the gas bearing 10. The top foil 2101 is a cylindrical foil. One side of the top foil 2101 overlaps the top of each corrugation of the bump foil assembly 220, and the other side of the top foil 2101 is used for clearance fit with the rotating shaft 20.

[0119] like Figure 4 As shown, further, the top foil 2101 includes a first top foil 211 and a second top foil 212, the first top foil 211 has the first inclined section 2111 as described above, the gap between the first inclined section 2111 and the outer periphery of the rotating shaft 20 gradually decreases from the first side to the second side of the first inclined section 2111, and the gap between the first inclined section 2111 and the rotating shaft 20 is wedge-shaped, so that the rotating shaft 20 generates a dynamic pressure effect when rotating.

[0120] like Figure 4 As shown, in some embodiments, the first side and the second side of the first inclined section 2111 are arranged along the direction of normal rotation of the rotating shaft 20, and the side of the hole wall of the foil assembly 200 away from the shaft hole also has a second inclined section 2112, the second inclined section 2112 and the first inclined section 2111 are arranged along the direction of normal rotation of the rotating shaft 20, the second inclined section 2112 has a third side and a fourth side arranged along the direction of normal rotation of the rotating shaft 20, the fourth side of the second inclined section 2112 is connected to the first side of the first inclined section 2111, and the distance between the second inclined section 2112 and the axis center of the shaft hole increases from the third side to the fourth side. When the rotating shaft 20 is inserted into the cavity, an air guide area 204 connected to the dynamic pressure effect generating area 203 is formed between the second inclined section 2112 and the outer periphery of the rotating shaft 20; the air guide area 204 is used to guide the airflow from the air guide area 204 into the dynamic pressure effect generating area.

[0121] by Figure 4For example, the normal rotation direction of the rotating shaft 20 is counterclockwise, the first side and the second side of the first inclined section 2111 are arranged in the counterclockwise direction, and the side of the foil assembly 200 away from the hole wall of the shaft hole also has a second inclined section 2112, the second inclined section 2112 and the first inclined section 2111 are arranged in the counterclockwise direction, the second inclined section 2112 has a third side and a fourth side arranged in the counterclockwise direction, the fourth side of the second inclined section 2112 is adjacent to the first side of the first inclined section 2111, and the distance between the second inclined section 2112 and the axis center of the shaft hole increases from the third side to the fourth side. When the rotating shaft 20 is inserted into the cavity, an air guide area 204 connected to the dynamic pressure effect generating area 203 is formed between the second inclined section 2112 and the outer periphery of the rotating shaft 20, and the air guide area 204 is used to guide the airflow from the air guide area 204 into the dynamic pressure effect generating area.

[0122] Furthermore, the first top foil 211 has a first inclined section 2111 and a second inclined section 2112, the first side and the second side of the first inclined section 2111 are arranged in a counterclockwise direction, the second inclined section 2112 and the first inclined section 2111 are arranged in a counterclockwise direction, the second inclined section 2112 has a third side and a fourth side arranged in a counterclockwise direction, the fourth side is adjacent to the first side, the distance between the second inclined section 2112 and the axis center of the shaft hole increases from the third side to the fourth side, and when the rotating shaft 20 is inserted into the cavity, an air guide area 204 connected to the dynamic pressure effect generating area 203 is formed between the second inclined section 2112 and the outer periphery of the rotating shaft 20.

[0123] Specifically in this embodiment, the second inclined section 2112 is an inclined straight plate. In other embodiments, the second inclined section 2112 may also be an arc-shaped plate.

[0124] In another embodiment, the normal rotation direction of the rotating shaft 20 is clockwise, the first side and the second side of the first inclined section 2111 are arranged in the clockwise direction, and the side of the foil assembly 200 away from the hole wall of the shaft hole also has a second inclined section 2112, the second inclined section 2112 and the first inclined section 2111 are arranged in the clockwise direction, the second inclined section 2112 has a third side and a fourth side arranged in the clockwise direction, the fourth side of the second inclined section 2112 is adjacent to the first side of the first inclined section 2111, and the distance between the second inclined section 2112 and the axis center of the shaft hole increases from the third side to the fourth side. When the rotating shaft 20 is inserted into the cavity, an air guide area 204 connected to the dynamic pressure effect generating area 203 is formed between the first inclined section 2111 and the outer periphery of the rotating shaft 20.

[0125] Furthermore, the first side and the second side of the first inclined section 2111 of the first top foil 211 are arranged in a clockwise direction, and the first top foil 211 also has a second inclined section 2112. The second inclined section 2112 and the first inclined section 2111 are arranged in a clockwise direction. The second inclined section 2112 has a third side and a fourth side arranged in a clockwise direction. The fourth side is adjacent to the first side. The distance between the second inclined section 2112 and the axis center of the shaft hole increases from the third side to the fourth side. When the rotating shaft 20 is inserted into the cavity, an air guide area 204 connected to the dynamic pressure effect generating area 203 is formed between the second inclined section 2112 and the outer periphery of the rotating shaft 20.

[0126] like Figure 2-Figure 5 As shown, in some embodiments, there are at least two top foils 2101, and at least two top foils 2101 are stacked along the radial direction of the shaft hole. The at least two top foils 2101 include a first top foil 211 and a second top foil 212, and the second top foil 212 is attached to the first top foil 211, and the second top foil 212 is located between the first top foil 211 and the bump foil assembly 220. The first top foil 211 is attached to the second top foil 212, and the bending radius of the contact surface of the first top foil 211 and the second top foil 212 is R2. The contact area between the first top foil 211 and the second top foil 212 is large, and compared with a single top foil directly contacting the bump foil, the damping of the gas bearing 10 can be improved.

[0127] like Figure 4 -like Figure 7 As shown, it should be noted that the second top foil 212 has a third inclined section 2121, and the third inclined section 2121 is fitted with the first inclined section 2111, so that the distance between the first inclined section 2111 and the axis of the shaft hole decreases from the first side to the second side.

[0128] like Figure 2 , Figure 6 and Figure 7 As shown, further, the first top foil 211 includes a first fixed end 2114 and a first free end 2115, the first top foil 211 extends clockwise from the first fixed end 2114 to the first free end 2115, the first fixed end 2114 is fixedly connected to the housing 100, the second top foil 212 includes a second fixed end 2123 and a second free end 2124, the second top foil 212 extends counterclockwise from the second fixed end 2123 to the second free end 2124, and the second fixed end 2123 is fixedly connected to the housing 100. The assembly directions of the first top foil 211 and the second top foil 212 are opposite, so that the first top foil 211 and the second top foil 212 can more easily generate relative movement, further improving the damping of the gas bearing 10.

[0129] Specifically, the first top foil 211 and the second top foil 212 are both cylindrical, the first top foil 211 is a nearly closed cylindrical shape with end-to-end connection, the head end of the first top foil 211 is a first fixed end 2114, the tail end of the first top foil 211 is a first free end 2115, and the first fixed end 2114 of the first top foil 211 is fixedly connected to the housing 100; the second top foil 212 is a non-closed cylindrical shape with end-to-end connection, the tail end of the second top foil 212 is a second fixed end 2123, the head end of the second top foil 212 is a second free end 2124, and the second fixed end 2123 of the second top foil 212 is fixedly connected to the housing 100. In this way, relative movement between the first top foil 211 and the second top foil 212 is easier to occur, further improving the damping of the gas bearing 10.

[0130] In another embodiment, the first top foil 211 includes a first fixed end 2114 and a first free end 2115, the first top foil 211 extends counterclockwise from the first fixed end 2114 to the first free end 2115, the first fixed end 2114 is fixedly connected to the shell 100, the second top foil 212 includes a second fixed end 2123 and a second free end 2124, the second top foil 212 extends clockwise from the second fixed end 2123 to the second free end 2124, and the second fixed end 2123 is fixedly connected to the shell 100.

[0131] like Figure 2 As shown, in some embodiments, the housing 100 is provided with a first mounting groove 110, and the top foil 2101 has a first mounting edge 201 disposed in the first mounting groove 110. The top foil 2101 can be positioned by being disposed in the first mounting groove 110 through the first mounting edge 201, which facilitates assembly.

[0132] Furthermore, the gas bearing 10 further includes a first fastener 300, and the housing 100 is further provided with a first mounting hole 130. The first fastener 300 is inserted into the first mounting hole 130 and squeezes the first mounting edge 201 to fix the top foil 2101 to the housing 100. After the first mounting edge 201 is arranged in the first mounting groove 110, it can be further fastened by the first fastener 300, so that the top foil and the housing 100 can be detachably connected, which is beneficial to the maintenance of the bearing.

[0133] Specifically, the first mounting hole 130 is connected to the first mounting groove 110. When the first mounting edge 201 is embedded in the first mounting groove 110, the first fastener 300 is inserted into the first mounting hole 130 and squeezes the first mounting edge 201, so that the side surface of the first mounting edge 201 is fixed by the squeezing force of the first fastener 300.

[0134] like Figure 2 , Figure 6 and Figure 7As shown, more specifically, the first mounting edge 201 includes a first sub-mounting edge 2113 and a second sub-mounting edge 2122, the first sub-mounting edge 2113 is arranged at the first fixed end 2114 of the first top foil 211, the second sub-mounting edge 2122 is arranged at the second fixed end 2123 of the second top foil 212, and the first sub-mounting edge 2113 and the second sub-mounting edge 2122 are attached and both arranged in the first mounting groove 110. The first fastener 300 is a pin, and when the first sub-mounting edge 2113 and the second sub-mounting edge 2122 are arranged in the first mounting groove 110, they are fastened by the pin.

[0135] In other embodiments, the top foil may also be fixed by a connection structure such as a snap-on screw.

[0136] like Figure 3-Figure 8 As shown, in some embodiments, the foil assembly 200 includes at least three bump foil assemblies 220, at least three bump foil assemblies 220 are respectively fixedly connected to the housing 100, and at least three bump foil assemblies 220 are opposite to each other and form an annular structure around the outer periphery of the rotating shaft 20. When the bearing rotates at a high speed, the deformation of the bump foil assembly 220 will change in real time due to the rotation of the bearing. By arranging at least three bump foil assemblies 220 on the outer periphery of the rotating shaft 20, each bump foil assembly 220 can adapt to the load change within a certain central angle range, thereby avoiding excessive force and deformation of a local bump foil assembly 2201.

[0137] Specifically in this embodiment, the foil assembly 200 includes three bump foil assemblies 220. The three bump foil assemblies 220 are arc-shaped as a whole, and each bump foil assembly 220 adapts to a load change of 120°. Each bump foil assembly 220 includes a first bump foil 221 and a second bump foil 222.

[0138] like Figure 8 As shown, further, the first corrugated foil 221 is provided with a first strip hole 2212, and the first strip hole 2212 is arranged to extend along the circumference of the first corrugated foil 221. The first strip hole 2212 can divide the first corrugated foil 221 into two parts, and the forces on each part do not affect each other or have little influence on each other, and when one part is deformed by force, it will not affect the other parts.

[0139] Furthermore, there are at least two first strip holes 2212, and the at least two first strip holes 2212 are arranged at intervals along the axial direction of the first corrugated foil 221. In this way, the first corrugated foil 221 can be divided into multiple parts, and when one part is deformed by force, other parts will not be affected.

[0140] Specifically in this embodiment, three first strip-shaped holes 2212 are disposed on each first corrugated foil 221 , and each first corrugated foil 221 is divided into four parts by the first strip-shaped holes 2212 .

[0141] Similarly, the second corrugated foil 222 is provided with a second strip hole 2222, and the second strip hole 2222 is arranged to extend along the circumference of the second corrugated foil 222. The second strip hole 2222 can divide the second corrugated foil 222 into two parts, and the forces on each part do not affect each other or have little influence on each other. When one part is deformed by force, it will not affect other parts.

[0142] Furthermore, there are at least two second strip holes 2222, and the at least two second strip holes 2222 are arranged at intervals along the axial direction of the second corrugated foil 222. In this way, the second corrugated foil 222 can be divided into multiple parts, and when one part is deformed by force, other parts will not be affected.

[0143] Specifically in this embodiment, three first strip holes 2212 are disposed on each second corrugated foil 222 , and each second corrugated foil 222 is divided into four parts by the second strip holes 2222 .

[0144] like Figure 2 and Fig.13 As shown, in some embodiments, the bump foil assembly 220 includes at least two bump foils 2203, and the at least two bump foils 2203 are stacked along the radial direction of the shaft hole. The at least two bump foils 2203 include a first bump foil 221 and a second bump foil 222. The second bump foil 222 is attached to the first bump foil 221, and the second bump foil 222 is located between the first bump foil 221 and the hole wall of the shaft hole.

[0145] like Figure 5 As shown, the first wave foil 221 and the second wave foil 222 are both corrugated, and the first wave foil 221 and the second wave foil 222 have the same wave height (H1=H2)-wave span (L1=L2)-matched bending radius (the bending radius of the contact surface is R5), so that the first wave foil 221 and the second wave foil 222 are completely fitted, thereby improving the bearing capacity of the gas bearing 10. In addition, since the first wave foil 221 and the second wave foil 222 are completely fitted, the contact area is increased, and when the shaft 20 rotates, the Coulomb friction effect between the first wave foil 221 and the second wave foil 222 is increased, thereby improving the damping.

[0146] like Figure 3-Figure 8 As shown, in some embodiments, the foil assembly 200 includes at least three bump foil assemblies 220, each bump foil assembly 220 is fixedly connected to the housing 100, and at least three bump foil assemblies 220 are opposite each other end to end and form a ring structure; each bump foil assembly 220 includes at least two bump foils, and at least two bump foils are arranged in sequence.

[0147] When the bearing rotates at high speed, the deformation of the bump foil assembly 220 will change in real time due to the rotation of the bearing. The foil assembly 200 includes at least three bump foil assemblies 220, each of which adapts to load changes within a certain central angle range, avoiding excessive stress and deformation of a local bump foil assembly 220.

[0148] like Figure 3 As shown, specifically in this embodiment, the foil assembly 200 includes three bump foil assemblies 220, each of which is arc-shaped; each bump foil assembly 220 includes at least two bump foils, and at least two bump foils are arranged in sequence, and each bump foil assembly 220 can adapt to a load change of 120°.

[0149] like Figure 2-Figure 8 As shown, in some embodiments, the housing 100 is provided with a second mounting groove 120, and the bump foil assembly 220 has a second mounting edge 202 disposed in the second mounting groove 120. The bump foil assembly 220 can be positioned by being disposed in the second mounting groove 120 through the second mounting edge 202, which facilitates assembly.

[0150] Furthermore, the gas bearing 10 further includes a second fastener 400, and the housing 100 is further provided with a second mounting hole 140. The second fastener 400 is inserted into the second mounting hole 140 and squeezes the second mounting edge 202 to fix the bump foil assembly to the housing 100. After the second mounting edge 202 is arranged in the second mounting groove 120, it can be further fastened by the second fastener 400, so that the bump foil assembly can be detachably connected to the housing 100, which is beneficial to the maintenance of the bearing.

[0151] Specifically, the second mounting hole 140 is connected to the second mounting groove 120. When the second mounting edge 202 is embedded in the second mounting groove 120, the second fastener 400 is inserted into the second mounting hole 140 and squeezes the second mounting edge 202, so that the side surface of the second mounting edge 202 is fixed by the squeezing force of the second fastener 400.

[0152] More specifically, the second mounting edge 202 includes a third sub-mounting edge 2213 and a fourth sub-mounting edge 2223, the third sub-mounting edge 2213 is disposed on the first corrugated foil 221, the fourth sub-mounting edge 2223 is disposed on the second corrugated foil 222, and the third sub-mounting edge 2213 and the fourth sub-mounting edge 2223 are attached and both disposed in the second mounting groove 120. The second fastener 400 is a pin, and after the third sub-mounting edge 2213 and the fourth sub-mounting edge 2223 are disposed in the second mounting groove 120, they are fastened by the pin.

[0153] like Figure 1-3As shown, further, the second mounting groove 120 is connected to the second mounting hole 140 and forms an assembly position, and at least two assembly positions are provided on the housing 100 at circumferential intervals along the axial hole. The number of assembly positions can be greater than the number of bump foil assemblies 220 for selective use of the bump foil assemblies 220.

[0154] like Figure 1 , Figure 2 and Figure 8 As shown, specifically in this embodiment, the first corrugated foil 221 in each corrugated foil assembly 220 is provided with a third sub-mounting edge 2213, and the second corrugated foil 2221 in each corrugated foil assembly 220 is provided with a fourth sub-mounting edge 2223, and each assembly position corresponds to the first corrugated foil 221 and the second corrugated foil 2221 which are fitted together, and the first corrugated foil 221 and the second corrugated foil 2221 which are fitted together are selectively inserted into the same mounting groove 120, and the second fastener 400 is penetrated into the second mounting hole 140 of the assembly position corresponding to the second mounting groove 120.

[0155] In other embodiments, the bump foil assembly 220 may also be fixed by a connection structure such as a buckle-screw.

[0156] According to the working principle of the gas bearing, the shaft is eccentric relative to the gas bearing under the action of gravity, and then a wedge-shaped gap is formed with the inner surface of the gas bearing. When the shaft is rotating at high speed, it continuously brings gas with a certain viscosity into the wedge-shaped gap, and the continuous entry of gas causes the gas film to generate a certain pressure. When the speed is increased to a certain level, the gas film force is sufficient to balance the shaft load, and the shaft and the bearing are completely separated. The speed at this time is called the bearing take-off speed, and the process of generating the above-mentioned gas film is called the dynamic pressure effect.

[0157] However, due to the low viscosity of the refrigerant, compared with oil-lubricated hydrodynamic bearings, the relevant gas bearings have low load-bearing capacity and small damping, resulting in high take-off speed of the shaft, low critical speed, and excessive vibration, which greatly limits the application of gas bearings in the refrigeration field.

[0158] Based on this, the gas bearings provided in some embodiments of the present disclosure are suitable for refrigerant corrugated foil dynamic pressure gas bearings, which improve the bearing capacity and damping of the bearing from a structural aspect.

[0159] In some embodiments, the gas bearing includes a housing 100 , a top foil assembly 210 , and at least three corrugated foil assemblies 220 .

[0160] like Figure 1As shown, the housing 100 is provided with an axial hole for the rotating shaft 20 to pass through. The top foil assembly 210 is inserted into the axial hole, and the top foil assembly 210 forms a cavity for the rotating shaft 20 to pass through. The top foil assembly 210 includes at least two flat top foils 2101, and the at least two top foils 2101 are stacked and matched with each other along the radial direction of the axial hole.

[0161] At least three corrugated foil assemblies 220 are arranged between the hole wall of the shaft hole and the top foil assembly 210, and support the top foil assembly 210; at least three foil assemblies 220 are opposite to each other end to end and form an annular structure around the outer circumference of the top foil assembly 210, and each of the at least three foil assemblies 220 includes at least two foils 2203 stacked and matched with each other, thereby improving the bearing capacity of the gas bearing.

[0162] The flat shape here means that the surface of the top foil 2101 has no undulations like the corrugated foil 2203 .

[0163] The wave foil 2203 is an elastic foil with a special waveform. Generally, the smaller the waveform height and the narrower the span, the stronger the bearing stiffness. When working, the elastic change of the waveform generates a supporting force, providing the main stiffness and partial damping for the bearing.

[0164] The bump foil assembly 220 includes at least two bump foils 2203 stacked in a matching manner, and the at least two bump foils 2203 stacked in a matching manner have the same waveform span (L1=L2), matching bending radius and the same or different waveform heights (H1=H2 or H1≠H2), which effectively increases the structural strength of the bump foil assembly 220 and improves the load-bearing capacity of the gas bearing.

[0165] In some embodiments, Figure 2 , Figure 4 and Figure 5 As shown, at least two matching stacked bump foils 2203 are integrally fitted. Since at least two matching stacked bump foils 2203 have the same waveform span (L1=L2), the same waveform height (H1=H2), matching bending radius, etc., at least two matching stacked bump foils 2203 can be integrally fitted in the circumferential direction, and the contact form is surface contact, which increases the contact area, effectively improves the structural strength of the bump foil assembly 220, and improves the bearing capacity and damping of the gas bearing.

[0166] In some embodiments, the corrugated foil 2203 includes a wavy portion 2201 and a flat portion 2202. Two adjacent corrugated foils 2203 that are stacked in a matching manner mean that the wavy portion 2201 of one corrugated foil 2203 is radially aligned and stacked with the wavy portion 2201 of the other corrugated foil 2203, and the flat portion 2202 of one corrugated foil 2203 is radially aligned and stacked with the flat portion 2202 of the other corrugated foil 2203.

[0167] The corrugated portion 2201 and the flat portion 2202 of the corrugated foil 2203 are alternately arranged at intervals. The starting point of the corrugated portion 2201 is connected to the flat portion 2202 and is located at the same plane height as the flat portion 2202 .

[0168] In other embodiments, Fig. 9 , Fig.10 and Fig.13 As shown, the corrugated foil 2203 includes a corrugated portion 2201 and a flat portion 2202 . There is a gap between the corrugated portions 2201 of two adjacent corrugated foils 2203 that are stacked and matched with each other, and the flat portions 2202 are in contact with each other.

[0169] Since there is a gap between the corrugated portions 2201 of two adjacent corrugated foils 2203 stacked in a matching manner and the flat portions 2202 are in close contact with each other, when the rotating shaft 20 rotates, the Coulomb friction effect between the two adjacent corrugated foils 2203 stacked in a matching manner increases, thereby improving the damping. However, the two adjacent corrugated foils 2203 stacked in a matching manner have different corrugated heights. For example: Fig.10 As shown, the corrugated foil 2203 far from the rotating shaft 20 is the second corrugated foil 222, and the corrugated height of the second corrugated foil 222 is H1. The corrugated foil 2203 close to the rotating shaft 20 is the first corrugated foil 221, and the corrugated height of the first corrugated foil 221 is H2. The fitting clearance between the corrugated parts 2201 of the two corrugated foils 2203 is X3. Since the material thickness of the two corrugated foils 2203 is the same, X3=H2-H1.

[0170] The corrugated portions 2201 of two adjacent corrugated foils 2203 stacked in a matching manner have different corrugation heights, wherein the corrugated foil 2203 with a relatively higher corrugation height has a lower stiffness than the corrugated foil 2203 with a relatively lower corrugation height.

[0171] Among them, the height H2 of the first corrugated foil 221 is greater than the height H1 of the second corrugated foil 222. The first corrugated foil 221 is a low-rigidity corrugated foil, which reduces the bearing stiffness, and is therefore conducive to reducing the bearing takeoff speed and bearing wear. The second corrugated foil 222 is a high-rigidity corrugated foil, which mainly provides a greater bearing capacity, because when the shaft takes off, as the speed increases, the shaft needs a greater load, and at this time, the height H2 of the low-rigidity first corrugated foil 221 is continuously compressed and reduced, that is, the gap X3 is continuously reduced, and when X3 is zero, the high-rigidity second corrugated foil 222 begins to participate in the deformation, and provides load-bearing together with the low-rigidity first corrugated foil 221.

[0172] In some embodiments, the gap X3 between the corrugated portions 2201 of two adjacent corrugated foils 2203 stacked and matched with each other is greater than or equal to 0 and less than or equal to 20 um.

[0173] When X3 is 0, the corrugated portions 2201 of two adjacent corrugated foils 2203 stacked in a matching manner have the same corrugated height, and the two are in close contact with each other, with the largest contact area. Therefore, the stiffness of the corrugated foil is the largest at this time, but the bearing take-off speed is also high. When X3 is 20um, the corrugated foil with a larger height first participates in the work to provide stiffness to the rotating shaft, effectively reducing the bearing take-off speed.

[0174] When X3 is greater than 20um, the bearing take-off speed can be further reduced. However, since X3 is relatively large at this time, the radial variable clearance of the bearing is relatively large. That is, when the shaft runs under high speed and heavy load environment, in the radial direction, the actual working clearance of the bearing is much larger than the design clearance, which will bring about problems such as large main frequency vibration and half-frequency vibration of the shaft.

[0175] like Fig.10 As shown, two adjacent corrugated foils 2203 that are stacked and matched with each other are respectively a first corrugated foil 221 and a second corrugated foil 222. The first corrugated foil 221 is closer to the rotating shaft 20 than the second corrugated foil 222. The inner diameter of the first corrugated foil 221 is R4, the outer diameter of the first corrugated foil 221 is R5, and the inner diameter of the second corrugated foil 222 is the same as the outer diameter of the first corrugated foil 221, also R5. The outer diameter of the second corrugated foil 222 is R6, which is the same as the inner diameter of the housing 100.

[0176] The inner diameter of the bump foil here refers to the distance from the flat portion of the bump foil to the center of the axial hole.

[0177] In some embodiments, Figure 3 As shown, the gas bearing includes at least three bump foil assemblies 220, which are opposite to each other end to end and form an annular structure around the rotating shaft 20, and each bump foil assembly 220 is fixedly connected to the housing 100. There is a first preset arc distance between two adjacent bump foil assemblies 220, and the central angle corresponding to the first preset arc distance is θ1.

[0178] In order to give full play to the adaptive characteristics of the gas bearing (that is, when the shaft 20 rotates at high speed, the load on the bearing at each rotation center angle of the shaft changes in real time, and the waveform deformation of the bearing changes with the load), at least three bump foil assemblies 220 are arranged along the circumference of the shaft 20, and the at least three bump foil assemblies 220 are evenly distributed along the circumference of the shaft 20. For example: Figure 1 and Figure 3 As shown, three bump foil assemblies 220 are arranged along the circumferential direction of the rotating shaft 20. Each bump foil assembly 220 can adapt to a load change of 120°.

[0179] In some embodiments, the bump foil assembly 220 includes a fixed end and a free end, the fixed end of the bump foil assembly 220 is fixedly connected to the housing 100, and the free end of one of the two adjacent bump foil assemblies 220 is adjacent to the fixed end of the other bump foil assembly 220 and has a first preset arc distance. The center angle corresponding to the first preset arc distance is θ1.

[0180] In some embodiments, Figure 4 and Fig. 9 As shown, the bump foil assembly 220 includes a fixed end and a free end. The fixed end of the bump foil assembly 220 is fixedly connected to the housing 100 . Along the rotation direction of the shaft 20 , the fixed end of the bump foil assembly 220 is located upstream of the free end.

[0181] In some embodiments, Figure 2 As shown, the housing 100 is provided with a second mounting groove 120 , and the bump foil assembly 220 has a second mounting edge 202 provided in the second mounting groove 120 .

[0182] In some embodiments, the gas bearing also includes a second fastener 400, and the shell 100 is also provided with a second mounting hole 140 connected to the second mounting groove 120; the second fastener 400 is passed through the second mounting hole 140 and squeezes the second mounting edge 202 in the second mounting groove 120 to fix the bump foil assembly 220 to the shell 100.

[0183] Each bump foil assembly 220 corresponds to a second mounting groove 120 and a second mounting hole 140 .

[0184] like Fig.11 As shown, the housing 100 is an annular, rotating part. Generally, its outer diameter is interference-fitted with other box parts, and its inner part supports and fixes the corrugated foil and the top foil by welding or fixing pins. Although the welding connection is reliable, it requires high positioning accuracy, otherwise there will be large welding stress, which affects the bearing performance. At the same time, the foil cannot be disassembled or removed after welding, which is not conducive to bearing maintenance.

[0185] Therefore, in some embodiments, Figure 2 As shown, the dual fixing method of fixing the second mounting edge 202 by the second mounting groove 120 and deforming and squeezing the second mounting edge 202 by the second fastener 400 improves the connection reliability and assembly efficiency of the bump foil assembly 220, and this method is detachable, which improves the bearing assembly efficiency and reliability.

[0186] like Figure 1 and Fig.11 As shown, since at least three bump foil assemblies 220 are provided in the shell 100, in order to improve the connection reliability of the bump foil assemblies 220, a plurality of groups of second mounting grooves 120 and second mounting holes 140 matching the number of the bump foil assemblies 220 are provided on the end surface of the shell 100, and the second mounting grooves 120 and the second mounting holes 140 are both axially through.

[0187] In some embodiments, Fig.13 As shown, the bump foil assembly 220 is provided with a strip hole 2204 , and the strip hole 2204 extends along the circumference of the shaft hole. Optionally, at least one of the two bump foils 2203 in the bump foil assembly 220 is provided with a strip hole 2204 .

[0188] In some embodiments, the bump foil assembly 220 is provided with at least two strip-shaped holes 2204 , and the at least two strip-shaped holes 2204 are arranged at intervals along the axial direction of the shaft hole.

[0189] In some embodiments, of two bump foils 2203 stacked and matched with each other, the thickness of the bump foil 2203 close to the rotating shaft 20 is smaller than the thickness of the bump foil 2203 far from the rotating shaft 20 .

[0190] In some embodiments, the thicknesses of two adjacent bump foils 2203 stacked and matched with each other are t1 and t2, respectively, and 0≤t1-t2≤0.1 mm.

[0191] For example, the two corrugated foils 2203 in the corrugated foil assembly 220 are respectively the first corrugated foil 221 and the second corrugated foil 222, which are stacked and matched with each other. The second corrugated foil 222 is close to the shell 100, and the material thickness of the second corrugated foil 222 is t1, t1=R6-R5. The corrugated foil away from the shell 100 is the first corrugated foil 221, and the material thickness of the first corrugated foil 221 is t2, t2=R5-R4. Optionally, 0≤t1-t2≤0.1mm.

[0192] When t1-t2=0, the structural stiffness of the second corrugated foil 222 is equal to that of the first corrugated foil 221. The two corrugated foils have similar material types and processing techniques, and the stiffness difference of the double-layer corrugated foil is controlled by the above-mentioned corrugation heights H2 and H1.

[0193] When t1-t2=0.1 mm, the structural stiffness of the second corrugated foil 222 is much greater than that of the first corrugated foil 221. The difference in corrugated height can further improve the comprehensive stiffness of the bearing, while also meeting the requirement of reducing the take-off speed.

[0194] When 0<t1-t2<0.1mm, the structural rigidity of the second corrugated foil 222 is also greater than the structural rigidity of the first corrugated foil 221, and the requirement of reducing the take-off rotation speed is also met.

[0195] When t1-t2>0.1mm, the second wave foil 222 is relatively thick, which can further improve the structural stiffness and meet the structural stiffness greater than that of the first wave foil 221. However, the large thickness of the second wave foil 222 will bring about processing difficulties, which is mainly reflected in the waveform pressing and bending forming, increasing the foil forming error and deviating from the design value.

[0196] In some embodiments, the top foil 2101 is a long cylindrical foil. In the radial direction, one side of the top foil assembly 210 is evenly overlapped on the top of each corrugated portion 2201 of the corrugated foil assembly 220, and generates friction through contact with the corrugated portion 2201, providing a part of damping for the bearing; the other side of the top foil assembly 210 is in clearance fit with the rotating shaft 20, forming an air film space required for the dynamic pressure effect.

[0197] In some embodiments, the top foil assembly 210 includes two flat top foils 2101 , and the two top foils 2101 are stacked and matched with each other along the radial direction of the shaft hole to improve the damping of the gas bearing.

[0198] In some embodiments, the two top foils 2101 are integrally adhered to each other.

[0199] The two flat top foils 2101 have matching bending radii, for example: Fig.10 As shown, the top foil 2101 close to the rotating shaft 20 is the first top foil 211, and the top foil 2101 away from the rotating shaft 20 is the second top foil 212. At the contact surface between the first top foil 211 and the second top foil 212, the inner diameter of the second top foil 212 is equal to the outer diameter of the first top foil 211, both of which are R2, so that they are completely integrally fitted to each other in the radial direction. The friction contact area of ​​the top foil is further increased through the integrally fitted fitting surfaces, thereby improving the damping.

[0200] like Fig.10 As shown, two top foils 2101 integrally bonded to each other are respectively a first top foil 211 and a second top foil 212. The first top foil 211 is closer to the rotating shaft 20 than the second top foil 212. The inner diameter of the first top foil 211 is R1, the outer diameter of the first top foil 211 is R2, and the inner diameter of the second top foil 212 is the same as the outer diameter of the first top foil 211, also R2. The outer diameter of the second top foil 212 is R3.

[0201] The damping of the gas bearing comes from the surface contact between the bump foil assembly 220 and the inner wall of the shell 100, the surface contact between the two bump foils 2203 in the bump foil assembly 220, the contact between the bump foil assembly 220 and the top foil 2101, and the contact between the two top foils 2101. When the shaft rotates at high speed, the bump foil assembly 220 and the top foil 2101 produce relative motion and generate Coulomb friction through the above-mentioned contact area to consume the bearing energy, which is the bearing damping.

[0202] In some embodiments, Figure 2 As shown, the housing 100 is provided with a first installation groove 110 , and at least two top foils 2101 each have a first installation edge 201 , and each first installation edge 201 is disposed in the first installation groove 110 .

[0203] In some embodiments, the gas bearing also includes a first fastener 300, and the shell 100 is also provided with a first mounting hole 130 connected to the first mounting groove 110. The first fastener 300 is passed through the first mounting hole 130 and squeezes the first mounting edges 201 of the two top foils 2101 to fix the two top foils 2101 to the shell 100.

[0204] In some embodiments, the dual fixing method of fixing the first mounting edge 201 by the first mounting groove 110 and deforming and extruding the first mounting edge 201 by the first fastener 300 improves the connection reliability and assembly efficiency of the top foil 2101, and this method is detachable, which improves the bearing assembly efficiency and reliability.

[0205] In some embodiments, Figure 3 As shown, the bump foil assembly 220 includes a fixed end and a free end. The fixed end of the bump foil assembly 220 is fixedly connected to the housing 100. Among two adjacent bump foil assemblies 220, the free end of one bump foil assembly 220 is adjacent to the fixed end of the other bump foil assembly 220 and has a first preset arc distance. The first mounting groove 110 is located within the range of the first preset arc distance. Fig. 9 shown.

[0206] In some embodiments, Fig. 9 As shown, within the range of the first preset arc distance, there is a fourth preset arc distance between the first mounting groove 110 and the free end of one of the above-mentioned bump foil assemblies 220, and there is a fifth preset arc distance between the first mounting groove 110 and the fixed end of the other above-mentioned bump foil assembly 220, wherein the fourth preset arc distance is smaller than the fifth preset arc distance.

[0207] In some embodiments, Fig. 9 As shown, the center angle corresponding to the fourth preset arc distance is θ2, 0<θ2<5°.

[0208] In some embodiments, Figure 4 and Fig. 9 As shown, each of the two adjacent top foils 2101 includes a fixed end and a free end, wherein a direction from the fixed end to the free end of one top foil 2101 is opposite to a direction from the fixed end to the free end of the other top foil 2101 .

[0209] In order to further enhance the damping of the bearing, the two top foils 2101 are assembled in opposite directions, so that the two top foils 2101 are more likely to generate relative movement.

[0210] like Fig. 9 As shown, the shaft rotates counterclockwise, the assembly direction from the fixed end of the first top foil 211 to the free end is clockwise, and the assembly direction from the fixed end of the second top foil 212 to the free end is counterclockwise.

[0211] In some embodiments, along the rotation direction of the rotating shaft 20, the installation direction of all the bump foil assemblies 220 is from the free end to the fixed end. This structural form is beneficial to improving the anti-turbulence ability of the bearing; the installation direction of the first top foil 211 is also from the free end to the fixed end, and the installation direction of the second top foil 212 located between the bump foil assembly 220 and the first top foil 211 is from the fixed end to the free end, mainly to generate relative motion to increase the bearing damping.

[0212] In some embodiments, of the two top foils 2101 , along the rotation direction of the shaft 20 , the fixed end of the top foil 2101 close to the shaft 20 is located upstream of the free end, and the fixed end of the top foil 2101 away from the shaft 20 is located downstream of its free end.

[0213] In some embodiments, the fixed ends of the top foils 2101 are located at the same assembly position of the housing 100 .

[0214] In some embodiments, of two adjacent top foils 2101 , the thickness of the top foil 2101 close to the rotation shaft 20 is greater than the thickness of the top foil 2101 far from the rotation shaft 20 .

[0215] In terms of thickness, the thickness of the two top foils 2101 is proportional to the structural rigidity. This is because after the thickness increases, the top foil 2101's ability to resist deformation is enhanced, and the same is true for the corrugated foil. However, whether it is the top foil or the corrugated foil, the increase in material thickness will increase the difficulty of forming and reduce the processing accuracy of the parts. Therefore, the thickness of the top foil 2101 material can generally be selected to be 0.1mm~0.3mm, and the thickness of the corrugated foil can generally be selected to be 0.1mm~0.2mm.

[0216] For example: Fig.10As shown, the two top foils 2101 include a first top foil 211 and a second top foil 212 , the material thickness of the second top foil 212 is t3 ( t3 = R3 − R2 ), and the material thickness of the first top foil 211 is t4 ( t4 = R2 − R1 ).

[0217] Optionally, 0≤t4-t3≤0.1mm, and the principle is the same as the above-mentioned corrugated foil.

[0218] When t4-t3>0.1mm, the first top foil 211 is too thick, which will cause processing difficulties, mainly in bending and forming. It cannot form a cylindrical shape with good curvature, which affects the formation of the radial air film gap.

[0219] In some embodiments, of two adjacent top foils 2101 , the stiffness of the top foil 2101 close to the rotation shaft 20 is greater than the stiffness of the top foil 2101 far from the rotation shaft 20 .

[0220] The rigidity of the first top foil 211 is greater than or equal to the rigidity of the second top foil 212 .

[0221] Taking into account that the first top foil 211 cooperates with the rotating shaft 20 and its inner diameter R1 bears the air film pressure, the material thickness t4 of the first top foil 211 is preferably larger. The second top foil 212 is located between the first top foil 211 and the bump foil assembly 220, mainly to increase the contact area, thereby increasing the damping of the bearing. Therefore, the material thickness t3 of the second top foil 212 should preferably be smaller, so as to improve the deformation ability of the second top foil 212, so as to fit the first top foil 211 and the bump foil assembly 220.

[0222] In some embodiments, the at least two top foils 2101 include a first top foil 211 and a second top foil 212 , and the at least two bump foils 2203 include a first bump foil 221 and a second bump foil 222 ;

[0223] The second corrugated foil 222 is located at a hole wall of the axial hole relative to the first corrugated foil 221, and the thickness of the second corrugated foil 222 is t1, and the thickness of the first corrugated foil 221 is t2;

[0224] The second top foil 212 is located at a hole wall of the shaft hole relative to the first top foil 211, the thickness of the second top foil 212 is t3, and the thickness of the first top foil 211 is t4;

[0225] Among them, t4=2t3=2t2=2t1.

[0226] In some embodiments, Fig. 9 As shown, the top foil 2101 includes a fixed end and a free end, wherein a second preset arc distance is provided between the fixed end and the free end of the top foil 2101 close to the rotating shaft 20, and a third preset arc distance is provided between the fixed end and the free end of the top foil 2101 away from the rotating shaft, and the third preset arc distance is greater than the second preset arc distance.

[0227] The rotating shaft 20 is a shaft-like, solid part. The rotating shaft 20 and the bearing clearance match to form a designed clearance X4 (not shown in the figure). The designed clearance X4 is actually the difference between the inner diameter R1 of the first top foil 211 and the outer diameter R7 of the rotating shaft 20, that is, X4 = R1-R7. The rotating shaft 20 performs high-speed rotation under the action of the electromagnetic field. When the speed reaches the designed value, the gas bearing 10 forms an air film through the dynamic pressure effect to suspend the rotating shaft 20.

[0228] It should be noted that for the processed shaft 20 and gas bearing 10, the design gap X4 is a fixed value. However, during operation, the shaft 20 rotates at high speed and is subjected to centrifugal force and thermal expansion force, which causes the outer diameter R7 of the shaft 20 to increase. Similarly, in addition to the centrifugal force and thermal expansion force caused by the shaft 20, the gas bearing 10 also experiences deformation of its own corrugated foil and top foil due to the air film force and the gravity of the shaft, which also causes the inner diameter R1 of the first top foil 211 to increase. Generally, the change of R1 is greater than that of R7, so the actual working gap X5 (not shown in the figure) is greater than the design gap X4.

[0229] Therefore, if Figure 3 and Fig. 9 As shown, an interval is designed between adjacent bump foil assemblies 220 in the circumferential direction, that is, a first preset arc distance, the center angle corresponding to the first preset arc distance is θ1, and the center angle corresponding to the fourth preset arc distance is θ2. When designing, the smaller the values ​​of θ1 and θ2 are, the larger the circumferential length of the bump foil assembly 220 is, the more waveforms can be arranged, that is, the greater the bearing capacity of the bearing, so generally θ1 and θ2 are less than 5°; but θ1 and θ2 are too small, when the working gap becomes larger, the non-free end of the bump foil assembly 220 extends in the circumferential direction, and the adjacent bump foil assemblies 220 interfere with each other, so the minimum values ​​of θ1 and θ2 should satisfy that the bearing is still greater than zero when the limit load deformation occurs.

[0230] In some embodiments, the top foil 2101 includes a fixed end and a free end, wherein the top foil 2101 closest to the rotating shaft 20, that is, the free end of the first top foil 211, is provided with a first inclined section 2111, and the distance between the first inclined section 2111 and the axis of the shaft hole decreases along the rotation direction of the rotating shaft 20. When the rotating shaft 20 is inserted into the cavity, the wedge-shaped convergence area formed between the first inclined section 2111 and the outer periphery of the rotating shaft 20 is the dynamic pressure effect generation area 203.

[0231] In some embodiments, the top foil 2101 closest to the rotating shaft 20, that is, the position where the fixed end of the first top foil 211 is located, is provided with a second inclined section 2112, and the distance between the second inclined section 2112 and the axis of the shaft hole increases along the rotation direction of the rotating shaft 20. When the rotating shaft 20 is inserted into the cavity, the wedge-shaped area formed between the second inclined section 2112 and the outer periphery of the rotating shaft 20 is an air guide area 204 connected to the dynamic pressure effect generating area 203, so as to improve the dynamic pressure effect of the bearing.

[0232] According to the previous description of the working principle of the wave foil dynamic pressure gas bearing, the key to the generation of the bearing air film is to form a dynamic pressure effect. Based on this, in some embodiments, a dynamic pressure effect generating area 203 and an air guide area 204 are formed to enhance the bearing dynamic pressure effect and reduce the bearing takeoff speed.

[0233] like Fig. 9 As shown, a wedge-shaped convergence area is formed between the first inclined section 2111 of the first top foil 211 and the outer periphery of the rotating shaft 20, which is a dynamic pressure effect generating area 203, and is manifested as a convergence gap gradually decreasing from X1 to X2 along the rotation direction. Among them, X1 is the maximum gap between the first inclined section 2111 and the rotating shaft 20, and X2 is the minimum gap between the first inclined section 2111 and the rotating shaft 20.

[0234] A wedge-shaped convergence area is formed between the second inclined section 2112 of the first top foil 211 and the outer periphery of the rotating shaft 20 as the air guiding area 204. Along the rotation direction, the gap of the air guiding area 204 increases from small to large, and no dynamic pressure effect is formed. The air guiding area 204 is mainly used to guide the airflow to transition from the gap to the dynamic pressure effect generating area 203.

[0235] In some embodiments, the top foil 2101 adjacent to the top foil closest to the rotating shaft 20 , that is, the location where the fixed end of the second top foil 212 is located, is provided with a third inclined section 2121 , and the third inclined section 2121 is in contact with the first inclined section 2111 .

[0236] In some embodiments, the end position of the free end of the top foil 2101 adjacent to the top foil closest to the rotating shaft 20, that is, the second top foil 212, is located at the starting position of the second inclined section 2112. The starting position of the second inclined section 2112 is the position where the second inclined section 2112 starts to tilt.

[0237] In some embodiments, Fig. 9 As shown, the bump foil assembly 220 corresponding to the position of the first inclined section 2111 is provided with a tail wave 2205 , which is configured to support the first inclined section 2111 , and the waveform height of the tail wave 2205 is lower than the waveform height of other corrugated portions 2201 of the bump foil assembly 220 .

[0238] In order to improve the structural strength of the dynamic pressure effect generating area 203, a tail wave 2205 is set in the wave foil assembly 220 corresponding to the position of the first inclined section 2111. The waveform height and span of the tail waves 2205 of the two wave foils 2203 in the wave foil assembly 220 are the same, so they are tightly fitted in the radial direction, that is, there is no similar wave foil fitting gap X3. This design is mainly to ensure the structural stability of the dynamic pressure effect generating area 203 and avoid air film impact at the inlet during the rapid formation of the air film.

[0239] Depend on Figure 4 It can be seen that, in addition to being formed by the first inclined section 2111 and the third inclined section 2121 , the convergence gaps X1 and X2 are also supported by the waveform structure indicated by the coda wave 2205 , thereby improving the structural strength of the dynamic pressure effect generating area 203 .

[0240] like Fig.12 As shown, there is a fifth preset arc distance between the free end and the fixed end of the second top foil 212 , and the central angle corresponding to the fifth preset arc distance is θ3, which is used to avoid the free end of the second top foil 212 away from the gas guide area 204 .

[0241] In some embodiments, the bump foil assembly 220 has two structural forms.

[0242] like Figure 8 2 shows the structure of two bump foils in the first bump foil assembly 220 . Both bump foils include a mounting edge, a plurality of strip holes, a plurality of corrugated portions, and a plurality of flat portions.

[0243] like Fig.13 As shown, the structure of two bump foils in the second bump foil assembly 220, both of which include a mounting edge, a plurality of strip holes, a plurality of wave-shaped portions, a plurality of flat portions, and a tail wave. In other words, the difference between the second bump foil assembly 220 and the first bump foil assembly 220 is that the tail wave is provided more. The second bump foil assembly 220 is correspondingly arranged at a position close to the first inclined section 2111 of the first top foil 211, and is used to support the first inclined section 2111.

[0244] In some embodiments, the bump foil assembly 220 includes a fixed end, a free end, and a plurality of corrugated portions 2201 arranged between the fixed end and the free end. The fixed end of the bump foil assembly 220 is fixedly connected to the shell 100. The free end of at least one bump foil assembly 220 is provided with a tail wave 2205, and the waveform height of the tail wave 2205 is lower than the waveform height of the corrugated portion 2201.

[0245] In some embodiments, three bump foil assemblies 220 are evenly distributed along the circumferential direction inside the housing 10, including two first-type bump foil assemblies 220 and one second-type bump foil assembly 220. The second-type bump foil assembly 220 is correspondingly arranged at a position close to the first inclined section 2111 of the first top foil 211, and is used to support the first inclined section 2111.

[0246] In some embodiments, the at least three corrugated bump foil assemblies 220 include three bump foil assemblies 220 , and the three bump foil assemblies 220 are evenly spaced apart along the circumference of the hole wall of the shaft hole.

[0247] An embodiment also relates to a compressor, comprising the above gas bearing.

[0248] In the conventional gas bearing 10 of the compressor, the rotating shaft 20 is eccentric relative to the bearing under the action of gravity, thereby forming a wedge-shaped gap with the inner surface of the bearing, and a dynamic pressure effect is formed through the wedge-shaped gap, so that the rotating shaft 20 is suspended. In the gas bearing 10 of the present application, since the foil assembly 200 has the first inclined section 211, and there is an obvious wedge-shaped area between the first inclined section 211 and the rotating shaft 20, the rotating shaft 20 can form an air film more easily and quickly when rotating.

[0249] An embodiment also relates to an air conditioning unit, comprising the compressor as described above.

[0250] In the conventional gas bearing 10 of the air conditioner, the rotating shaft 20 is eccentric relative to the bearing under the action of gravity, thereby forming a wedge-shaped gap with the inner surface of the bearing, and a dynamic pressure effect is formed through the wedge-shaped gap, so that the rotating shaft 20 is suspended. In the gas bearing 10 of the present application, since the foil assembly 200 has the first inclined section 211, and there is an obvious wedge-shaped area between the first inclined section 211 and the rotating shaft 20, the rotating shaft 20 can form an air film more easily and quickly when rotating.

[0251] Based on the above-mentioned embodiments of the present invention, the technical features of some of the embodiments may be beneficially combined with one or more other embodiments unless explicitly denied.

[0252] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0253] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A gas bearing, It is characterized in that include: The housing (100) is provided with a shaft hole for the rotating shaft (20) to pass through; A top foil assembly (210) is inserted into the shaft hole, the top foil assembly (210) encloses a cavity for the rotating shaft (20) to pass through, the top foil assembly (210) comprises at least two flat top foils (2101), the at least two top foils (2101) are stacked and matched with each other along the radial direction of the shaft hole; the top foil (2101) comprises a fixed end and a free end, wherein: A first inclined section (2111) is provided at the position of the free end of the top foil (2101) closest to the rotating shaft (20); along the rotation direction of the rotating shaft (20), the distance between the first inclined section (2111) and the axis of the shaft hole decreases; a dynamic pressure effect generating area (203) is formed between the first inclined section (2111) and the outer periphery of the rotating shaft (20); A second inclined section (2112) is provided at the fixed end of the top foil (2101) closest to the rotating shaft (20); along the rotation direction of the rotating shaft (20), the distance between the second inclined section (2112) and the axis of the shaft hole increases; an air guide area (204) connected to the dynamic pressure effect generating area (203) is formed between the second inclined section (2112) and the outer periphery of the rotating shaft (20); the air guide area (204) is used to guide airflow from the air guide area (204) into the dynamic pressure effect generating area (203); and At least three corrugated foil assemblies (220) are arranged between the hole wall of the axial hole and the top foil assembly (210), and support the top foil assembly (210); the at least three foil assemblies (220) are opposite to each other end to end and form an annular structure around the outer circumference of the top foil assembly (210); each of the at least three foil assemblies (220) comprises at least two foils (2203) stacked and matched with each other.

2. The gas bearing according to claim 1, It is characterized in that The at least two corrugated foils (2203) that are stacked and matched with each other are integrally bonded.

3. The gas bearing according to claim 1, It is characterized in that The corrugated foil (2203) comprises a corrugated portion (2201) and a flat portion (2202); a gap is provided between the corrugated portions (2201) of two adjacent corrugated foils (2203) stacked in a matching manner, and the flat portions (2202) are fitted together.

4. The gas bearing according to claim 3, It is characterized in that The gap between the corrugated portions (2201) of two adjacent corrugated foils (2203) stacked in a matching manner is greater than or equal to 0 and less than or equal to 20 um.

5. The gas bearing according to claim 3, It is characterized in that The corrugated portions (2201) of the two adjacent corrugated foils (2203) stacked in a matching manner have different corrugation heights, wherein the corrugated foil (2203) with a relatively higher corrugation height has a lower stiffness than the corrugated foil (2203) with a relatively lower corrugation height.

6. The gas bearing according to claim 1, It is characterized in that The bump foil assembly (220) comprises a fixed end and a free end, the fixed end of the bump foil assembly (220) being fixedly connected to the housing (100), and the free end of one of the two adjacent bump foil assemblies (220) being adjacent to the fixed end of the other bump foil assembly (220) and having a first preset arc distance.

7. The gas bearing according to claim 6, It is characterized in that The center angle corresponding to the first preset arc distance is θ1, 0<θ1<5°.

8. The gas bearing according to claim 1, It is characterized in that The bump foil assembly (220) comprises a fixed end and a free end, the fixed end of the bump foil assembly (220) being fixedly connected to the housing (100), and along the rotation direction of the rotating shaft (20), the fixed end of the bump foil assembly (220) is located upstream of the free end.

9. The gas bearing according to claim 1, It is characterized in that The housing (100) is provided with a second installation groove (120), and the bump foil assembly (220) has a second installation edge (202) provided in the second installation groove (120).

10. The gas bearing according to claim 9, It is characterized in that The housing (100) further comprises a second fastener (400); the housing (100) is further provided with a second mounting hole (140) communicating with the second mounting groove (120); the second fastener (400) is passed through the second mounting hole (140) and presses the second mounting edge (202) in the second mounting groove (120) so as to fix the bump foil assembly (220) to the housing (100).

11. The gas bearing according to claim 1, It is characterized in that The bump foil assembly (220) is provided with a strip-shaped hole (2204), and the strip-shaped hole (2204) extends along the circumference of the shaft hole.

12. The gas bearing according to claim 11, It is characterized in that The bump foil assembly (220) is provided with at least two strip-shaped holes (2204), and the at least two strip-shaped holes (2204) are arranged at intervals along the axial direction of the shaft hole.

13. The gas bearing according to claim 1, It is characterized in that Of the at least two corrugated foils (2203) stacked and matched with each other, the thickness of the corrugated foil (2203) close to the rotating shaft (20) is smaller than the thickness of the corrugated foil (2203) far from the rotating shaft (20).

14. The gas bearing according to claim 13, It is characterized in that The thickness of the corrugated foil (2203) close to the rotating shaft (20) is t2, and the thickness of the corrugated foil (2203) far from the rotating shaft (20) is t1, and 0≤t1-t2≤0.1mm.

15. The gas bearing according to claim 1, It is characterized in that Among the at least two top foils (2101), the thickness of the top foil (2101) close to the rotating shaft (20) is greater than the thickness of the top foil (2101) far from the rotating shaft (20).

16. The gas bearing according to claim 15, It is characterized in that The thickness of the top foil (2101) close to the rotating shaft (20) is t4, and the thickness of the top foil (2101) far from the rotating shaft (20) is t3, 0≤t4-t3≤0.1mm.

17. The gas bearing according to claim 1, It is characterized in that The at least two top foils (2101) include a first top foil (211) and a second top foil (212); the at least two corrugated foils (2203) include a first corrugated foil (221) and a second corrugated foil (222); The second corrugated foil (222) is closer to the hole wall of the axial hole than the first corrugated foil (221), the thickness of the second corrugated foil (222) is t1, and the thickness of the first corrugated foil (221) is t2; The second top foil (212) is located closer to the hole wall of the axial hole than the first top foil (211), the thickness of the second top foil (212) is t3, and the thickness of the first top foil (211) is t4; Among them, t4=2t3=2t2=2t1.

18. The gas bearing according to claim 1, It is characterized in that The top foil (2101) comprises a fixed end and a free end, and of two adjacent top foils (2101), a second preset arc distance is provided between the fixed end and the free end of the top foil (2101) close to the rotating shaft (20), and a third preset arc distance is provided between the fixed end and the free end of the top foil (2101) far from the rotating shaft, and the third preset arc distance is greater than the second preset arc distance.

19. The gas bearing according to claim 1, It is characterized in that The housing (100) is provided with a first installation groove (110), and the at least two top foils (2101) each have a first installation edge (201), and each of the first installation edges (201) is arranged in the first installation groove (110).

20. The gas bearing according to claim 19, It is characterized in that The invention also comprises a first fastener (300), the housing (100) is further provided with a first mounting hole (130) communicating with the first mounting groove (110), the first fastener (300) is passed through the first mounting hole (130) and presses the first mounting edges (201) of the at least two top foils (2101) so that the at least two top foils (2101) are fixedly connected to the housing (100).

21. The gas bearing according to claim 19, It is characterized in that The bump foil assembly (220) comprises a fixed end and a free end, the fixed end of the bump foil assembly (220) being fixedly connected to the housing (100), and of two adjacent bump foil assemblies (220), the free end of one bump foil assembly (220) is adjacent to the fixed end of the other bump foil assembly (220) and has a first preset arc distance, and the first mounting groove (110) is located within the range of the first preset arc distance.

22. The gas bearing according to claim 21, It is characterized in that Within the range of the first preset arc distance, there is a fourth preset arc distance between the first mounting groove (110) and the free end of one of the bump foil assemblies (220), and there is a fifth preset arc distance between the first mounting groove (110) and the fixed end of the other bump foil assembly (220), wherein the fourth preset arc distance is smaller than the fifth preset arc distance.

23. The gas bearing according to claim 22, It is characterized in that The center angle corresponding to the fourth preset arc distance is θ2, 0<θ2<5°.

24. The gas bearing according to claim 1, It is characterized in that Each top foil (2101) of the at least two top foils (2101) comprises a fixed end and a free end, wherein a direction from the fixed end to the free end of one top foil (2101) is opposite to a direction from the fixed end to the free end of another top foil (2101).

25. The gas bearing according to claim 24, It is characterized in that In two adjacent top foils (2101), along the rotation direction of the rotating shaft (20), the fixed end of the top foil (2101) close to the rotating shaft (20) is located upstream of the free end, and the fixed end of the top foil (2101) away from the rotating shaft (20) is located downstream of its free end.

26. The gas bearing according to claim 24, It is characterized in that The fixed ends of the at least two top foils (2101) are located at the same assembly position of the housing (100).

27. The gas bearing according to claim 1, It is characterized in that A third inclined section (2121) is provided at the fixed end of the top foil (2101) adjacent to the top foil closest to the rotating shaft (20), and the third inclined section (2121) is fitted with the first inclined section (2111).

28. The gas bearing according to claim 1, It is characterized in that The end position of the free end of the top foil (2101) adjacent to the top foil closest to the rotating shaft (20) is located at the starting position of the second inclined section (2112).

29. The gas bearing according to claim 1, It is characterized in that The corrugated foil assembly (220) corresponding to the position of the first inclined section (2111) is provided with a tail wave (2205), and the tail wave (2205) is configured to support the first inclined section (2111), and the waveform height of the tail wave (2205) is lower than the waveform height of other corrugated parts (2201) of the corrugated foil assembly (220).

30. The gas bearing according to claim 1, It is characterized in that Of the two adjacent top foils (2101), the stiffness of the top foil (2101) close to the rotation axis (20) is greater than the stiffness of the top foil (2101) far from the rotation axis (20).

31. The gas bearing according to claim 1, It is characterized in that The bump foil assembly (220) comprises a fixed end, a free end, and a plurality of corrugated portions (2201) arranged between the fixed end and the free end; the fixed end of the bump foil assembly (220) is fixedly connected to the housing (100); the free end of at least one bump foil assembly (220) is provided with a tail wave (2205); the height of the waveform of the tail wave (2205) is lower than the height of the waveform of the corrugated portion (2201).

32. The gas bearing according to claim 1, It is characterized in that The at least three corrugated foil assemblies (220) comprise three foil assemblies (220), and the three foil assemblies (220) are evenly spaced along the circumference of the hole wall of the axial hole.

33. A compressor, It is characterized in that Comprising a gas bearing as claimed in any one of claims 1 to 32 above.

34. An air conditioning unit, It is characterized in that Comprising a compressor as claimed in claim 33 above.

Images