Gas bearings, bearing assemblies and compressors

Abstract

The present disclosure relates to a gas bearing, a bearing assembly and a compressor. The gas bearing (30) comprises: a bearing housing (31), the outer peripheral surface of which has at least one groove (314) configured to form a pressure chamber (316); at least one bottom foil (32) arranged on the inner side of the inner peripheral surface of the bearing housing (31) and corresponding to the at least one groove (314); at least one bump foil (33) arranged on the side of at least one bottom foil (32) away from the bearing housing (31) and corresponding to the at least one groove (314); a top foil (34) arranged on the side of at least one bump foil (33) away from the bearing housing (31), wherein the bottom of the groove (314) has a plurality of through holes (313), and the plurality of through holes (313) are configured to allow the pressure gas in the pressure chamber (316) to enter between the bearing housing (31) and the corresponding bottom foil (32) and act on the surface of the bottom foil (32). The embodiment of the present disclosure can quickly form a dynamic pressure gas film of the bearing during the start-stop stage of the rotor.

Description

Technical Field

[0001] The present disclosure relates to the field of bearings, and in particular to a gas bearing, a bearing assembly and a compressor. Background Art

[0002] Gas lubrication technology was first proposed in the mid-19th century and developed rapidly in the mid-20th century. The emergence of this technology broke the dominant position of liquid lubrication technology and made a qualitative leap in lubrication technology. Gas bearings are new bearings based on this new lubrication technology. They have a series of advantages such as low friction loss, good stability, low vibration, and oil-free lubrication. They have broad application prospects in the fields of high-speed turbines, machine tool manufacturing, and space technology.

[0003] Gas bearings use gas as a lubricant and take advantage of the gas's adsorption, transport (diffusivity, viscosity and thermal conductivity) and compressibility characteristics. Based on the fluid dynamic pressure effect, static pressure effect and extrusion effect, a gas film is formed during friction to support the load and reduce friction.

[0004] According to the different mechanisms of lubricating gas film generation, gas bearings can be divided into dynamic pressure gas bearings, static pressure gas bearings and extrusion type gas bearings. The foil dynamic pressure gas radial bearing is the type of gas bearing with the most research literature available. Its typical structure is generally composed of a bearing shell, a top foil and a corrugated foil. The corrugated foil is an elastic foil with a special waveform. When working, it generates a supporting force through the elastic change of the waveform, providing the main stiffness and partial damping for the bearing; the top foil is a long cylindrical foil. In the radial direction, one side of the top foil is evenly overlapped on the top of each corrugation of the corrugated foil, and the friction generated by the contact with the corrugated foil provides another part of the damping for the bearing; the other side of the top foil cooperates with the rotor gap to form the air film space required for the dynamic pressure effect.

[0005] Under the action of gravity, the shaft becomes eccentric relative to the bearing, forming a wedge-shaped gap with the inner surface of the 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 gas film force is sufficient to balance the shaft load, the shaft and the bearing are completely separated. The process of generating the above gas film is called the dynamic pressure effect.

[0006] A hydrostatic gas bearing is a bearing that uses an external gas supply system to provide gas with a certain pressure. The gas is then transported to the gap between the bearing and the rotor through the bearing throttle, thereby forming an air film in the gap to support the external load. The air film pressure in the bearing gap can be adjusted by the bearing throttle and the gas supply system. According to the different throttles, there are common small-hole hydrostatic gas bearings and porous hydrostatic gas bearings. Summary of the invention

[0007] Research has found that during the start and stop of the rotor, due to insufficient speed, the gas film cannot be quickly formed through the dynamic pressure principle. At this time, the top foil of the dynamic pressure gas bearing and the rotor will have dry friction, which will affect the bearing life. In addition, the force condition of the rotor is not constant, especially in high-speed turbine centrifuges. The working conditions often change with the actual application of the terminal. The dynamic pressure gas bearing in the related technology is difficult to adjust the load capacity according to the working conditions.

[0008] The hydrostatic bearing in the related art has the advantages of large load-bearing capacity, stable operation and long life. However, when the rotor speed is high, the hydrostatic bearing cannot effectively absorb and suppress the rotor vibration due to the lack of damping mechanism.

[0009] In view of this, the embodiments of the present disclosure provide a gas bearing, a bearing assembly and a compressor, which can quickly form a dynamic pressure gas film of the bearing during the start-stop phase of the rotor.

[0010] In one aspect of the present disclosure, there is provided a gas bearing, comprising:

[0011] A bearing housing having an outer peripheral surface with at least one groove configured to form a pressure chamber;

[0012] at least one bottom foil, disposed inside the inner circumferential surface of the bearing housing and corresponding to the at least one groove;

[0013] At least one bump foil is respectively arranged on a side of the at least one bottom foil away from the bearing housing and corresponds to the at least one groove;

[0014] a top foil, arranged on a side of the at least one bump foil away from the bearing housing,

[0015] The bottom of the at least one groove has a plurality of through holes, and the plurality of through holes are configured to allow the pressurized gas in the pressure chamber to enter between the bearing housing and the corresponding bottom foil and act on the surface of the bottom foil.

[0016] In some embodiments, the at least one groove comprises a plurality of grooves spaced apart along the circumference of the bearing housing.

[0017] In some embodiments, the plurality of through holes include at least two through hole groups, the at least two through hole groups are distributed along the circumference of the bearing housing, and the at least two through hole groups are configured to gradually increase pressure along the rotation direction of the rotor supported by the gas bearing.

[0018] In some embodiments, the number of through holes in the at least two through hole groups is configured to increase along the rotation direction of the rotor supported by the gas bearing, and / or the diameter of the through holes in each through hole group of the at least two through hole groups is configured to increase along the rotation direction of the rotor supported by the gas bearing.

[0019] In some embodiments, the at least two through hole groups include a first through hole group, a second through hole group, and a third through hole group arranged along the circumference of the bearing housing, the diameters of the multiple through holes respectively included in the first through hole group, the second through hole group, and the third through hole group are the same, and the number of through holes in the first through hole group is less than the number of through holes in the second through hole group, and the number of through holes in the second through hole group is less than the number of through holes in the third through hole group.

[0020] In some embodiments, the at least one groove includes at least two sector annular grooves, each sector annular groove having two first groove walls opposite to each other along the circumferential direction of the bearing housing and two second groove walls opposite to each other along the axial direction of the bearing housing.

[0021] In some embodiments, the at least one bottom foil comprises:

[0022] Arc plate, the cross section is in the shape of an arc;

[0023] At least three folding plates are connected to at least three edges of the arc plate and extend radially outward relative to the arc plate.

[0024] The inner wall of the bearing housing has at least three embedding grooves, and the at least three folding plates are respectively embedded in the at least three embedding grooves.

[0025] In some embodiments, each bottom foil has two folding plates arranged opposite to each other along the circumferential direction and one folding plate arranged along the axial direction, which are respectively embedded in three embedding grooves of the inner wall of the bearing housing, so that the bottom foil and the inner wall of the bearing housing form an axially open gas outflow end.

[0026] In some embodiments, each bottom foil has two folding plates arranged opposite to each other along the circumferential direction and two folding plates arranged along the axial direction, which are respectively embedded in four embedding grooves of the inner wall of the bearing housing, so that the bottom foil and the inner wall of the bearing housing form a closed air cavity.

[0027] In some embodiments, the top foil comprises:

[0028] A first top foil, located at a side of the at least one bump foil away from the bearing housing, supporting the at least one bump foil in a radial direction;

[0029] The second top foil is located at a side of the first top foil away from the bearing housing and supports the first top foil in a radial direction.

[0030] Among them, the first end of the first top foil and the first end of the second top foil are connected to the inner wall of the bearing housing through a fixing pin and a first pin hole wire groove located on the inner wall of the bearing housing, and the second end of the first top foil extends in the opposite direction to the second end of the second top foil.

[0031] In one aspect of the present disclosure, there is provided a bearing assembly comprising:

[0032] A bearing support having a cavity and a vent hole communicating with the cavity;

[0033] The aforementioned gas bearing is located in the cavity,

[0034] The at least one groove of the bearing housing and the cavity wall of the cavity form a pressure cavity.

[0035] In some embodiments, the outer wall of the bearing housing is interference fit with the cavity in the radial direction.

[0036] In some embodiments, the bearing assembly further comprises:

[0037] The rotor amplitude detection unit is arranged on the bearing support and is located on one side of the gas bearing along the axial direction of the gas bearing, and is configured to detect the amplitude of the rotor supported by the gas bearing during rotation.

[0038] The vent hole is configured to be connected to an external air supply device, and the amount of air supply received is adjusted according to the amplitude.

[0039] In some embodiments, the rotor amplitude detection unit includes:

[0040] At least two eddy current displacement sensors are distributed at different angular positions along the circumference of the gas bearing.

[0041] In some embodiments, the rotor amplitude detection unit includes two eddy current displacement sensors that are 90 degrees apart in the circumferential direction of the gas bearing.

[0042] In one aspect of the present disclosure, a compressor is provided, comprising the aforementioned bearing assembly.

[0043] Therefore, according to the embodiment of the present disclosure, a bottom foil is arranged between the inner circumferential surface of the bearing housing and the wave foil, and static pressure is applied to the bottom foil through the groove on the bearing housing and the through hole at the bottom of the groove, so that during the start-stop stage of the rotor, the static pressure air film formed on the outside of the bottom foil is utilized to quickly form a dynamic pressure air film between the top foil and the rotor, thereby reducing the wear between the top foil and the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0045] The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0046] Figure 1 is a schematic diagram of the matching structure between some embodiments of the bearing assembly according to the present disclosure and the rotor;

[0047] Figure 2 yes Figure 1 Schematic diagram of the structure after partial sectioning;

[0048] Figure 3 yes Figure 1 A schematic diagram of the longitudinal section of the structure;

[0049] Figure 4 yes Figure 1 Schematic diagram of the structure in axial perspective;

[0050] Figure 5 yes Figure 3 Schematic diagram of the structure of the AA section;

[0051] Figure 6 yes Figure 5 An enlarged schematic diagram of the area indicated by the middle circle B;

[0052] Figure 7 yes Figure 6 An enlarged schematic diagram of the area indicated by the middle circle C;

[0053] Figure 8 is a schematic structural diagram of a bearing housing in some embodiments of a gas bearing according to the present disclosure;

[0054] Fig. 9 yes Figure 8 Schematic diagram of the structure in axial perspective;

[0055] Fig. 10A yes Fig. 9 Structural diagram of the middle DD section;

[0056] Fig. 10B is a schematic cross-sectional view of a partial structure of a bearing housing in some embodiments of a gas bearing according to the present disclosure;

[0057] Fig.11A is a schematic structural diagram of a bottom foil in some embodiments of a gas bearing according to the present disclosure from an axial perspective;

[0058] Fig. 11B yes Fig.11A Schematic diagram of the three-dimensional structure.

[0059] It should be understood that the size of each part shown in the accompanying drawings is not drawn according to the actual proportional relationship. In addition, the same or similar reference numerals represent the same or similar components. DETAILED DESCRIPTION

[0060] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0061] The words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0062] In the present disclosure, when a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other device without an intermediate device, or may not be directly connected to the other device but have an intermediate device.

[0063] All terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as those understood by ordinary technicians in the field to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0064] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0065] like Figure 1-11B As shown, the embodiments of the present disclosure provide a gas bearing, a bearing assembly and a compressor, which can quickly form a dynamic pressure gas film of the bearing during the start-stop phase of the rotor.

[0066] refer to Figure 1-Figure 7 In some embodiments, the present disclosure provides a bearing assembly, including: a bearing support 20 and a gas bearing 30. The bearing support 20 has a cavity and a vent hole 21 connected to the cavity. The gas bearing 30 is located in the cavity and can support the rotor 10 located in the gas bearing 30 and rotating.

[0067] The vent hole 21 of the bearing support 20 can be connected to an external gas supply device, and the high-pressure gas provided by the external gas supply device can reach the outside of the gas bearing 30 through the vent hole 21. The external gas supply device can be an active gas supply device such as a pump, or a gas circuit with higher pressure in the equipment used for the bearing assembly.

[0068] refer to Figure 6 In some embodiments, the gas bearing 30 includes: a bearing housing 31, at least one bottom foil 32, at least one bump foil 33 and a top foil 34. The outer peripheral surface of the bearing housing 31 has at least one groove 314, which is configured to form a pressure chamber 316. The pressure chamber 316 can be formed by the at least one groove 314 of the bearing housing 31 and the cavity wall of the cavity of the bearing support 20.

[0069] At least one bottom foil 32 is disposed on the inner side of the inner circumferential surface of the bearing housing 31, and corresponds to the at least one groove 314. At least one bump foil 33 is disposed on a side of the at least one bottom foil 32 away from the bearing housing 31, and also corresponds to the at least one groove 314. The top foil 34 is disposed on a side of the at least one bump foil 33 away from the bearing housing 31. When the rotor 10 rotates, a dynamic pressure gas film can be formed between the top foil 34 and the rotor 10.

[0070] In order to allow the gas in the pressure chamber 316 to reach between the bearing housing 31 and the corresponding bottom foil 32, a plurality of through holes 313 may be provided at the bottom of at least one groove 314. These through holes 313 enable the pressurized gas in the pressure chamber 316 to enter between the bearing housing 31 and the corresponding bottom foil 32 and act on the surface of the bottom foil 32.

[0071] The function of the multiple through holes on the above-mentioned bearing housing 31 is equivalent to a small-hole static pressure gas bearing. The high-pressure gas supplied by the external air supply device acts on the bottom foil 32 after throttling, thereby forming a static pressure air film on the outside of the bottom foil 32, so that the static pressure air film can be used to quickly form a dynamic pressure air film between the top foil and the rotor during the start and stop phases of the rotor, thereby reducing the wear between the top foil and the rotor.

[0072] In the bearing assembly, the bottom foil and the bearing housing as well as the bottom foil and the bump foil can move relative to each other and generate friction, which can consume part of the vibration of the rotor and realize part of the damping of the gas bearing.

[0073] In some embodiments, only one groove 314 (eg, an annular groove) and a corresponding bottom foil 32 may be provided on the bearing housing 31. Figure 5 and Figure 8 In some embodiments, the bearing housing 31 may include a plurality of grooves 314, such as Figure 5 and Figure 8 There are three grooves 314 shown, each groove 314 corresponds to a bottom foil 32 and a bump foil 33 .

[0074] The plurality of grooves 314 may be distributed at intervals along the circumference of the bearing housing 31, that is, each groove 314 may be located at a different angular position. In some embodiments, each groove has the same length and is arranged at equal angular intervals to make the static pressure air film formed more balanced.

[0075] In some embodiments, the outer wall of the bearing housing 31 and the cavity of the bearing support 20 are radially interference fit. For example, a protrusion structure may be formed between the two adjacent grooves 314, and the protrusion structure may be used to radially interfere with the inner wall of the cavity of the bearing support 20. In other embodiments, the bearing housing 31 may be fixed in the cavity of the bearing support 20 by means of clamping, bonding, welding, screw connection, or screw bolt connection.

[0076] refer to Figure 6 , Figure 8 , Fig. 10A and Fig. 10B In some embodiments, the plurality of through holes 313 include at least two through hole groups. Each through hole group may include at least one through hole. The at least two through hole groups are distributed along the circumference of the bearing housing 31. In other words, each through hole group occupies a circumferential range in the groove. In some embodiments, the at least two through hole groups may be configured to gradually increase the pressure applied to the bottom foil along the rotation direction ω of the rotor 10 supported by the gas bearing 30.

[0077] In order to gradually increase the pressure along the direction ω of the at least two through-hole groups, referring to FIG. 10A , in some embodiments, the number of through-holes in the at least two through-hole groups may be configured to increase along the rotation direction ω of the rotor 10 supported by the gas bearing 30. Fig. 10A and Fig. 10B In the embodiment, the at least two through hole groups include a first through hole group 313a, a second through hole group 313b, and a third through hole group 313c arranged along the circumferential direction of the bearing housing 31. The diameters of the plurality of through holes 313 respectively included in the first through hole group 313a, the second through hole group 313b, and the third through hole group 313c are the same, and the number of through holes in the first through hole group 313a is less than the number of through holes in the second through hole group 313b, and the number of through holes in the second through hole 313 is less than the number of through holes in the third through hole group 313c.

[0078] By increasing the number of through holes, the air pressure input to the outer side of the bottom foil can be increased, and by arranging different numbers of through holes at different circumferential positions in a groove, multiple pressure zones with different pressures between the bottom foil and the bearing housing can be realized. Different pressure zones can form wedge-shaped gaps of different sizes. Fig. 10B Along the rotation direction ω of the rotor 10, the first through hole group 313a, the second through hole group 313b and the third through hole group 313c correspond to the low pressure area, the medium pressure area and the high pressure area respectively. The air pressure in these pressure areas can change the wedge-shaped gap formed between the rotor 10 and the top foil 34 at different positions.

[0079] The low-pressure area can form a wedge-shaped gap X3 between the rotor 10 and the top foil 34, the medium-pressure area can form a wedge-shaped gap X2 between the rotor 10 and the top foil 34, and the high-pressure area can form a wedge-shaped gap X1 between the rotor 10 and the top foil 34. Among them, the wedge-shaped gap X1 is smaller than the wedge-shaped gap X2, and the wedge-shaped gap X2 is smaller than the wedge-shaped gap X3. In this way, the effect of the wedge-shaped gap changing from large to small along the rotation direction ω of the rotor 10 is achieved. In this way, the gas bearing can form a dynamic pressure gas film faster during the start-stop stage or low-speed stage of the rotor.

[0080] In other embodiments, the diameter of the through holes 313 in each of the at least two through hole groups is configured to increase along the rotation direction ω of the rotor 10 supported by the gas bearing 30. By increasing the diameter of the through holes, an effect similar to increasing the number of through holes can also be achieved. In other words, assuming that the number of through holes in each through hole group is the same, the through hole groups with different through hole diameters can achieve a plurality of pressure zones with different pressures between the bottom foil and the bearing housing, and the through hole group with a larger through hole diameter can achieve a pressure zone with a higher pressure.

[0081] Of course, for designers, the number of through holes and the through hole diameter in each through hole group can be set accordingly according to actual needs to achieve different pressure zones.

[0082] refer to Figure 5 and Figure 6 In some embodiments, at least one groove 314 includes at least two fan-shaped grooves. Figure 5 In the embodiment, the bearing housing 31 may have three fan-shaped annular grooves. The fan-shaped annular groove here refers to the shape of the groove on the cross section of the bearing housing 31, wherein the outer ring of the fan-shaped annular groove is the outer ring of the bearing housing 31, and the inner ring is the bottom of the groove.

[0083] exist Figure 8 In the embodiment, each sector annular groove has two first groove walls 314a opposite to each other along the circumferential direction of the bearing housing 31 and two second groove walls 314b opposite to each other along the axial direction of the bearing housing 31. These four groove walls can form a closed pressure chamber 316 with the inner wall of the cavity of the bearing support 20.

[0084] refer to Figure 8 , Fig.11A and Fig. 11B In some embodiments, at least one bottom foil 32 includes an arc plate 321 and at least three folding plates 322. The cross section of the arc plate 321 is arc-shaped, and the cross section is perpendicular to the axis of the gas bearing 30. At least three folding plates 322 are connected to at least three edges of the arc plate 321 and extend radially outward relative to the arc plate 321. The inner wall of the bearing housing 31 has at least three embedding grooves 315, and the at least three folding plates 322 are respectively embedded in the at least three embedding grooves 315.

[0085] On the one hand, the embedded structure of the folding plate and the embedded groove can realize a limited and movable connection between the bottom foil and the bearing housing, adjust the distance between the arc plate and the bearing housing by the gas pressure acting on the arc plate, and use the folding plate to achieve the effect of gas gathering. On the other hand, the friction between the folding plate and the embedded groove during relative motion can consume part of the vibration of the rotor and realize part of the damping of the gas bearing.

[0086] exist Fig.11A and Fig. 11B In the embodiment, each bottom foil 32 has two folding plates 322 arranged opposite to each other in the circumferential direction and one folding plate 322 arranged in the axial direction, which are respectively embedded in three embedding grooves 315 of the inner wall of the bearing housing 31, so that the bottom foil 32 and the inner wall of the bearing housing 31 form a gas outflow end open in the axial direction. In this way, the three folding plates are used to prevent gas leakage from these three directions, thereby building up pressure between the bottom foil and the bearing housing, and the gas outflow end can promote the flow of high-pressure gas.

[0087] In other embodiments, each bottom foil 32 has two folding plates 322 arranged opposite to each other in the circumferential direction and two folding plates 322 arranged in the axial direction, which are respectively embedded in four embedding grooves 315 of the inner wall of the bearing housing 31, so that the bottom foil 32 and the inner wall of the bearing housing 31 form a closed air cavity. The static pressure effect is improved by the cooperation of the four folding plates and the four embedding grooves, and the static pressure gas can flow out from the gap between the folding plates and the embedding grooves.

[0088] refer to Figure 5 and Figure 6 , one end of each bump foil 33 can be connected to the inner wall of the bearing housing 31 through a fixing pin and a second pin hole wire groove 312 located on the inner wall of the bearing housing 31. In some embodiments, the top foil 34 includes a first top foil 341 and a second top foil 342. The first top foil 341 is located on a side of the at least one bump foil 33 away from the bearing housing 31, and supports the at least one bump foil 33 in a radial direction. The second top foil 342 is located on a side of the first top foil 341 away from the bearing housing 31, and supports the first top foil 341 in a radial direction. The first end of the first top foil 341 and the first end of the second top foil 342 are both connected to the inner wall of the bearing housing 31 through a fixing pin and a first pin hole wire groove 311 located on the inner wall of the bearing housing 31, and the second end of the first top foil 341 and the second end of the second top foil 342 extend in opposite directions.

[0089] By providing a first top foil and a second top foil extending in opposite directions, relative motion can be generated between the two top foils when the rotor rotates, thereby generating friction, which can consume part of the vibration of the rotor and form part of the damping of the gas bearing.

[0090] refer to Figure 1-Figure 4 In some embodiments, the bearing assembly further comprises a rotor amplitude detection unit. The rotor amplitude detection unit is disposed on the bearing support 20 and is located on one side of the gas bearing 30 along the axial direction of the gas bearing 30. The rotor amplitude detection unit can detect the amplitude of the rotor 10 supported by the gas bearing 30 during rotation. The vent hole 21 can be connected to an external air supply device, and the amount of air supply received can be adjusted according to the amplitude.

[0091] exist Figure 1-Figure 4 In the embodiment, the rotor amplitude detection unit includes at least two eddy current displacement sensors 40. The at least two eddy current displacement sensors 40 are distributed at different angular positions along the circumference of the gas bearing 30. For example, the eddy current displacement sensor 40 is fixed to the bearing support 20 by threads.

[0092] In order to reduce the number of sensors, it is preferred that the rotor amplitude detection unit includes two eddy current displacement sensors 40 that are 90 degrees apart in the circumferential direction of the gas bearing 30. When the rotor 10 is in a stationary state, the two eddy current displacement sensors 40 can detect the initial position of the rotor 10. When the rotor 10 rotates, the rotor amplitude is different under the action of different speeds and external forces. By comparing with the initial position, the measured rotor amplitude can reflect the position of the rotor in real time on the one hand, and on the other hand, it can provide feedback on whether the rotor's air film thickness is appropriate. Appropriate air film thickness can make the rotor amplitude small and stable.

[0093] As mentioned above, different wedge-shaped gaps corresponding to different pressure zones are realized by multiple through-hole groups. As the pressure of the high-pressure gas entering the outer side of the bottom foil increases, the changes of the above-mentioned wedge-shaped gaps become more obvious, and the difference increases. As the pressure of the high-pressure gas entering the outer side of the bottom foil decreases, the difference of the above-mentioned wedge-shaped gaps decreases. In this way, the static pressure can be adjusted by controlling the high-pressure gas entering the pressure chamber, thereby adjusting the wedge-shaped gap, thereby forming a dynamic pressure gas film of different thicknesses, so that the bearing can adapt to changes in working conditions and provide corresponding bearing capacity.

[0094] For example, when the rotor rotates at high speed, the rotor needs a greater bearing support force. The bearing support force can be provided by reducing the thickness of the dynamic pressure gas film. At this time, the pressure of the high-pressure gas introduced is reduced, so that the difference between the wedge gaps corresponding to each pressure zone (for example, wedge gaps X3, X2, X1) becomes smaller. At the same time, the eddy current displacement sensor 40 detects the amplitude of the rotor in real time, and adjusts different pressures until a stable and small rotor amplitude is obtained.

[0095] The various embodiments of the above-mentioned bearing assembly can be applied to various types of equipment having a rotor, such as a compressor. Therefore, the present disclosure also provides a compressor, comprising any embodiment of the above-mentioned bearing assembly.

[0096] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0097] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A gas bearing (30), characterized in that: include: A bearing housing (31) having at least one groove (314) on its outer peripheral surface, configured to form a pressure chamber (316); At least one bottom foil (32) is arranged inside the inner circumferential surface of the bearing housing (31) and corresponds to the at least one groove (314); At least one bump foil (33), respectively arranged on a side of the at least one bottom foil (32) away from the bearing housing (31), and respectively corresponding to the at least one groove (314); A top foil (34) is arranged on a side of the at least one bump foil (33) away from the bearing housing (31), The bottom of the at least one groove (314) has a plurality of through holes (313), and the plurality of through holes (313) are configured to allow the pressurized gas in the pressure chamber (316) to enter between the bearing housing (31) and the corresponding bottom foil (32) and act on the surface of the bottom foil (32).

2. The gas bearing (30) according to claim 1, characterized in that: The at least one groove (314) comprises a plurality of grooves (314) distributed at intervals along the circumference of the bearing housing (31).

3. The gas bearing (30) according to claim 1, characterized in that: The plurality of through holes (313) include at least two through hole groups, the at least two through hole groups are distributed along the circumference of the bearing housing (31), and the at least two through hole groups are configured to gradually increase pressure along the rotation direction (ω) of the rotor (10) supported by the gas bearing (30).

4. The gas bearing (30) according to claim 3, characterized in that The number of through holes in the at least two through hole groups is configured to increase along the rotation direction (ω) of the rotor (10) supported by the gas bearing (30), and / or the diameter of the through holes (313) in each through hole group of the at least two through hole groups is configured to increase along the rotation direction (ω) of the rotor (10) supported by the gas bearing (30).

5. The gas bearing (30) according to claim 4, characterized in that The at least two through hole groups include a first through hole group (313a), a second through hole group (313b) and a third through hole group (313c) arranged along the circumferential direction of the bearing housing (31); the diameters of the plurality of through holes (313) respectively included in the first through hole group (313a), the second through hole group (313b) and the third through hole group (313c) are the same, and the number of through holes in the first through hole group (313a) is less than the number of through holes in the second through hole group (313b), and the number of through holes in the second through hole group (313) is less than the number of through holes in the third through hole group (313c).

6. The gas bearing (30) according to claim 1, characterized in that The at least one groove (314) includes at least two sector annular grooves, each sector annular groove having two first groove walls (314a) opposite to each other along the circumference of the bearing housing (31) and two second groove walls (314b) opposite to each other along the axial direction of the bearing housing (31).

7. The gas bearing (30) according to claim 1, characterized in that The at least one bottom foil (32) comprises: The arc plate (321) has an arc-shaped cross section; At least three folding plates (322) are connected to at least three edges of the circular arc plate (321) and extend radially outward relative to the circular arc plate (321). The inner wall of the bearing housing (31) has at least three embedding grooves (315), and the at least three folding plates (322) are respectively embedded in the at least three embedding grooves (315).

8. The gas bearing (30) according to claim 7, characterized in that Each bottom foil (32) has two folding plates (322) arranged opposite to each other in the circumferential direction and one folding plate (322) arranged in the axial direction, which are respectively embedded in three embedding grooves (315) on the inner wall of the bearing housing (31), so that the bottom foil (32) and the inner wall of the bearing housing (31) form a gas outflow end that is open in the axial direction.

9. The gas bearing (30) according to claim 7, characterized in that Each bottom foil (32) has two folding plates (322) arranged opposite to each other in the circumferential direction and two folding plates (322) arranged in the axial direction, which are respectively embedded in four embedding grooves (315) on the inner wall of the bearing housing (31), so that the bottom foil (32) and the inner wall of the bearing housing (31) form a closed air cavity.

10. The gas bearing (30) according to claim 1, characterized in that The top foil (34) comprises: A first top foil (341), located on a side of the at least one bump foil (33) away from the bearing housing (31), and supporting the at least one bump foil (33) in a radial direction; The second top foil (342) is located on a side of the first top foil (341) away from the bearing housing (31) and supports the first top foil (341) in a radial direction. Wherein, the first end of the first top foil (341) and the first end of the second top foil (342) are connected to the inner wall of the bearing housing (31) through a fixing pin and a first pin hole wire groove (311) located on the inner wall of the bearing housing (31), and the second end of the first top foil (341) and the second end of the second top foil (342) extend in opposite directions.

11. A bearing assembly, characterized in that: include: A bearing support (20) having a cavity and a vent hole (21) communicating with the cavity; The gas bearing (30) according to any one of claims 1 to 10, located in the cavity, Wherein, at least one groove (314) of the bearing housing (31) and a cavity wall of the cavity form a pressure cavity (316).

12. The bearing assembly according to claim 11, characterized in that The outer wall of the bearing housing (31) and the cavity are interference-fitted in the radial direction.

13. The bearing assembly according to claim 11, characterized in that Also includes: A rotor amplitude detection unit is arranged on the bearing support (20) and is located on one side of the gas bearing (30) along the axial direction of the gas bearing (30), and is configured to detect the amplitude of the rotor (10) supported by the gas bearing (30) during rotation. The vent hole (21) is configured to be connected to an external air supply device, and the amount of air supply received is adjusted according to the amplitude.

14. The bearing assembly according to claim 13, characterized in that The rotor amplitude detection unit comprises: At least two eddy current displacement sensors (40) are distributed at different angular positions along the circumference of the gas bearing (30).

15. The bearing assembly according to claim 14, characterized in that The rotor amplitude detection unit comprises two eddy current displacement sensors (40) which are 90 degrees apart in the circumferential direction of the gas bearing (30).

16. A compressor, characterized in that: include: The bearing assembly according to any one of claims 11 to 15.

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