CN114688072A - Gas bearing, bearing assembly and compressor - Google Patents

Abstract

The present disclosure relates to a gas bearing, a bearing assembly and a compressor. The gas bearing (30) comprises: a bearing housing (31) having at least one groove (314) on an outer peripheral surface thereof configured to form a pressure chamber (316); at least one bottom foil (32) disposed inside an inner circumferential surface of the bearing housing (31) and corresponding to the at least one groove (314), respectively; at least one bump foil (33) respectively arranged on one side of the at least one bottom foil (32) far away from the bearing shell (31) and respectively corresponding to the at least one groove (314); a top foil (34) arranged on a side of the at least one bump foil (33) facing away from the bearing housing (31), wherein a groove bottom of the groove (314) has a plurality of through holes (313), the plurality of through holes (313) being configured to let pressure gas within the pressure chamber (316) enter between the bearing housing (31) and the corresponding bottom foil (32) and act on a surface of the bottom foil (32). The embodiment of the disclosure can quickly form a dynamic pressure air film of the bearing in the starting and stopping stages of the rotor.

Description

Gas bearing, bearing assembly and compressor

Technical Field

The present disclosure relates to the field of bearings, and more particularly, to a gas bearing, a bearing assembly, and a compressor.

Background

Gas lubrication technology was first proposed in the middle of the 19 th century and developed rapidly in the middle of the 20 th century. The emergence of the technology breaks the dominance of the liquid lubrication technology, so that the lubrication technology generates a qualitative leap. The gas bearing is a novel bearing generated based on the novel lubrication technology, has a series of advantages of small friction loss, good stability, small vibration, oil-free lubrication and the like, and has wide application prospects in the fields of high-speed turbines, machine tool manufacturing, space technology and the like.

The gas bearing uses gas as a lubricant, and utilizes the characteristics of gas such as adsorptivity, transportability (diffusivity, viscosity and thermal conductivity) and compressibility, and forms a gas film to support load and reduce friction based on the action of fluid dynamic pressure effect, static pressure effect and extrusion effect during friction.

Gas bearings can be classified into dynamic pressure gas bearings, static pressure gas bearings, and squeeze type gas bearings according to the mechanism of generation of a lubricating gas film. The foil dynamical pressure gas radial bearing is the most studied gas bearing in the current research literature, and the typical structure of the foil dynamical pressure gas radial bearing generally comprises a bearing shell, a top foil and a wave foil. The bump foil is an elastic foil with a special waveform, and when the bearing works, a supporting force is generated through the elastic change of the waveform, so that main rigidity and partial damping are provided for the bearing; the top foil is a long cylindrical foil, one surface of the top foil is uniformly lapped on the top end of each corrugation of the corrugated foil in the radial direction, and the friction force generated by the contact of the top foil and the corrugated foil provides the other part of damping for the bearing; the other side of the top foil is in clearance fit with the rotor to form an air film space required by a dynamic pressure effect.

The rotating shaft is eccentric relative to the bearing under the action of gravity, and a wedge-shaped gap is formed between the rotating shaft and the inner surface of the bearing. When the rotating shaft rotates at a high speed, gas with certain viscosity is continuously brought into the wedge-shaped gap, and the gas continuously enters to enable the gas film to generate certain pressure. When the air film force is sufficient to balance the load of the rotating shaft, the shaft is completely separated from the bearing, and the process generated by the air film is called dynamic pressure effect.

Hydrostatic gas bearings refer to a gas supplied under pressure by an external gas supply system, and then the gas is delivered through a bearing restrictor to a gap between the bearing and the rotor, thereby forming a gas film at the gap to support an external load. The air film pressure of the bearing gap can be adjusted through a bearing restrictor and an air supply system. According to the difference of the throttler, a static pressure gas bearing with a small hole and a static pressure gas bearing with a porous hole are common.

Disclosure of Invention

Research shows that in the process of starting and stopping the rotor, because the rotating speed is insufficient, an air film cannot be quickly formed by a dynamic pressure principle, and at the moment, the top foil of the dynamic pressure gas bearing is in dry friction with the rotor, so that the service life of the bearing is influenced. In addition, the stress condition of the rotor is not constant, especially on a high-speed turbine centrifuge, the working condition is frequently changed along with the practical application of the tail end, and the dynamic pressure gas bearing in the related technology is difficult to realize the adjustment of the bearing capacity along with the working condition.

The hydrostatic bearing in the related art has the advantages of large bearing capacity, stable operation, long service life and the like, but when the speed of the rotor is high, the hydrostatic bearing cannot effectively absorb and restrain the vibration of the rotor due to the lack of a damping mechanism.

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

In one aspect of the present disclosure, there is provided a gas bearing including:

a bearing housing having at least one groove on an outer circumferential surface thereof, configured to form a pressure chamber;

at least one bottom foil arranged on the inner side of the inner circumferential surface of the bearing shell and corresponding to the at least one groove respectively;

the at least one bump foil is arranged on one side, away from the bearing shell, of the at least one bottom foil and corresponds to the at least one groove respectively;

a top foil arranged on a side of the at least one bump foil remote from the bearing housing,

wherein a groove bottom of the at least one groove has a plurality of through holes configured to allow gas under pressure within the pressure chamber to enter between the bearing housing and the corresponding bottom foil and act on a surface of the bottom foil.

In some embodiments, the at least one groove comprises a plurality of grooves spaced circumferentially along the bearing housing.

In some embodiments, the plurality of through holes includes at least two through hole groups distributed along a circumferential direction of the bearing housing, and the at least two through hole groups are configured to gradually increase in pressure in a rotational direction of a rotor supported by the gas bearing.

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

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 a circumferential direction of the bearing housing, and the diameters of a plurality of 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 of the first through hole group is less than the number of through holes of the second through hole group, and the number of through holes of the second through hole group is less than the number of through holes of the third through hole group.

In some embodiments, the at least one groove comprises at least two sector-shaped annular grooves, each sector-shaped annular groove having two first groove walls opposing in a circumferential direction of the bearing housing and two second groove walls opposing in an axial direction of the bearing housing.

In some embodiments, the at least one base foil comprises:

the cross section of the arc plate is arc-shaped;

at least three flanged plates connected to at least three edges of the circular arc plate and extending outward in a radial direction relative to the circular arc plate,

the inner wall of the bearing shell is provided with at least three embedded grooves, and the at least three folding plates are embedded in the at least three embedded grooves respectively.

In some embodiments, each bottom foil has two folding plates arranged opposite to each other in the circumferential direction and one folding plate arranged in the axial direction, and the two folding plates 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 a gas outflow end which is open in the axial direction.

In some embodiments, each bottom foil has two folding plates arranged opposite to each other in the circumferential direction and two folding plates arranged in the axial direction, and the two folding plates 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.

In some embodiments, the top foil comprises:

a first top foil on a side of the at least one bump foil remote from the bearing housing, radially supporting the at least one bump foil;

a second top foil on a side of the first top foil remote from the bearing housing, radially supporting the first top foil,

the first end of the first top foil and the first end of the second top foil are connected with the inner wall of the bearing shell through a fixed pin and a first pin hole line groove in the inner wall of the bearing shell, and the extending direction of the second end of the first top foil is opposite to that of the second end of the second top foil.

In one aspect of the present disclosure, there is provided a bearing assembly including:

the bearing support is provided with a cavity and a vent hole communicated with the cavity;

the aforementioned gas bearing, located within the cavity,

wherein the at least one groove of the bearing housing forms a pressure chamber with a chamber wall of the cavity.

In some embodiments, the bearing housing outer wall is a radially interference fit with the cavity.

In some embodiments, the bearing assembly further comprises:

a rotor amplitude detection unit provided on the bearing holder and located at one side of the gas bearing in an axial direction of the gas bearing, configured to detect an amplitude of a rotor supported by the gas bearing when the rotor rotates,

wherein the vent is configured to be connected to an external air supply device, and the amount of air supply received is adjusted according to the amplitude.

In some embodiments, the rotor amplitude detection unit includes:

at least two eddy current displacement sensors distributed at different angular positions along the circumference of the gas bearing.

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

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

Therefore, according to the embodiment of the disclosure, the bottom foil is arranged between the inner circumferential surface of the bearing shell and the bump foil, and static pressure action is applied to the bottom foil through the grooves on the bearing shell and the through holes at the bottoms of the grooves, so that a dynamic pressure air film is quickly formed between the top foil and the rotor by using the static pressure air film formed outside the bottom foil in the start-stop stage of the rotor, and abrasion between the top foil and the rotor is reduced.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

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

FIG. 1 is a schematic view of a mating structure between some embodiments of a bearing assembly and a rotor according to the present disclosure;

FIG. 2 is a schematic view of the structure of FIG. 1, partially cut away;

FIG. 3 is a schematic structural view in longitudinal section of FIG. 1;

FIG. 4 is a schematic view of the structure of FIG. 1 from an axial perspective;

FIG. 5 is a schematic structural view of the AA section of FIG. 3;

FIG. 6 is an enlarged schematic view of the area indicated by circle B in FIG. 5;

FIG. 7 is an enlarged schematic view of the area indicated by circle C in FIG. 6;

FIG. 8 is a structural schematic view of a bearing housing in some embodiments of a gas bearing according to the present disclosure;

FIG. 9 is a schematic view of the structure of FIG. 8 from an axial perspective;

FIG. 10A is a schematic structural view of the DD section in FIG. 9;

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

FIG. 11A is a schematic view of a bottom foil at an axial view in some embodiments of a gas bearing according to the present disclosure;

fig. 11B is a schematic perspective view of fig. 11A.

It should be understood that the dimensions of the various parts shown in the figures are not drawn to scale in practice. Further, the same or similar reference numerals denote the same or similar components.

Detailed Description

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 disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the 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, numerical expressions, and numerical values set forth in these embodiments should be construed as merely illustrative, and not limiting.

The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

In the present disclosure, when it is described that a specific device is located between a first device and a second device, there may or may not be an intervening device between the specific device and the first device or the second device. When a particular device is described as being coupled to other devices, that particular device may be directly coupled to the other devices without intervening devices or may be directly coupled to the other devices with intervening devices.

All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

As shown in fig. 1 to 11B, an embodiment of the present disclosure provides a gas bearing, a bearing assembly, and a compressor, which can quickly form a dynamic pressure film of the bearing during a start-stop stage of a rotor.

Referring to fig. 1-7, in some embodiments, the present disclosure provides a bearing assembly comprising: a bearing support 20 and a gas bearing 30. The bearing support 20 has a cavity and a vent hole 21 communicating with the cavity. The gas bearing 30 is located in the cavity and is capable of supporting the rotor 10, which is located in the gas bearing 30 and rotates.

The vent holes 21 of the bearing holder 20 may be connected to an external gas supply device, and high-pressure gas supplied from the external gas supply device may reach the outside of the gas bearing 30 through the vent holes 21. The external air supply device can be an active air supply device such as a pump and the like, and can also be an air path with higher pressure in equipment to which the bearing assembly is applied.

Referring to fig. 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 circumferential surface of the bearing housing 31 has at least one groove 314 configured to form a pressure chamber 316. The pressure chamber 316 may be formed by the at least one recess 314 of the bearing housing 31 and the chamber wall of the cavity of the bearing support 20.

At least one bottom foil 32 is disposed inside the inner circumferential surface of the bearing housing 31, and corresponds to the at least one groove 314, respectively. At least one bump foil 33 is arranged on a side of the at least one bottom foil 32 facing away from the bearing housing 31, respectively, also corresponding to the at least one groove 314, respectively. A top foil 34 is arranged on a side of the at least one bump foil 33 facing away from the bearing housing 31. The top foil 34 may form a dynamic pressure film with the rotor 10 when the rotor 10 rotates.

In order to enable 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 in each case at the groove bottom of the at least one recess 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.

The plurality of through holes on the bearing housing 31 function as a small-hole static pressure gas bearing, and high-pressure gas supplied by an external gas supply device acts on the bottom foil 32 after throttling, so that a static pressure gas film is formed outside the bottom foil 32, and a dynamic pressure gas film is quickly formed between the top foil and the rotor by using the static pressure gas film in the starting and stopping stage of the rotor, thereby reducing the abrasion between the top foil and the rotor.

In the bearing assembly, the bottom foil and the bearing housing and the bottom foil and the bump foil are relatively movable and generate friction, by which part of the vibration of the rotor can be dissipated, achieving a part of the damping of the gas bearing.

In some embodiments, only one recess 314 (e.g. an annular groove) and a corresponding one of the bottom foils 32 may be provided on the bearing housing 31. Referring to fig. 5 and 8, in some embodiments, the bearing housing 31 may include a plurality of recesses 314, such as the three recesses 314 shown in fig. 5 and 8, one bottom foil 32 and one bump foil 33 for each recess 314.

The plurality of grooves 314 may be spaced apart along the circumference of the bearing housing 31, i.e. each groove 314 may be located at a different angular position. In some embodiments, each groove is of equal length and is equally angularly spaced so as to provide more uniform static pressure films.

In some embodiments, the outer wall of the bearing housing 31 is a radial interference fit with the cavity of the bearing support 20. For example, the two adjacent grooves 314 may form a protruding structure therebetween, and the protruding structure may be used for interference fit with the inner wall of the cavity of the bearing support 20 in the radial direction. In other embodiments, the bearing housing 31 may be fixed in the cavity of the bearing support 20 by clamping, bonding, welding, screwing, or bolting.

Referring to fig. 6, 8, 10A, and 10B, in some embodiments, the plurality of through holes 313 includes at least two through hole groups. Each set of through holes may comprise at least one through hole. The at least two sets of through holes are distributed along the circumferential direction of the bearing housing 31, in other words each set of through holes occupies a circumferential extent in the groove. In some embodiments, at least two sets of through holes may be configured to apply a gradually increasing pressure to the bottom foil in the direction of rotation ω of the rotor 10 supported by the gas bearing 30.

In order to achieve a gradual increase of the pressure in the direction ω of the at least two groups of through holes, referring to fig. 10A, in some embodiments the number of through holes of the at least two groups of through holes may be configured to increase in the direction ω of rotation of the rotor 10 supported by the gas bearing 30. For example, in fig. 10A and 10B, 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 that are arranged in the circumferential direction of the bearing housing 31. The diameters of a plurality of through holes 313 included in the first through hole group 313a, the second through hole group 313b, and the third through hole group 313c are the same, the number of through holes of the first through hole group 313a is less than that of through holes of the second through hole group 313b, and the number of through holes of the second through hole group 313 is less than that of through holes of the third through hole group 313 c.

The pressure input to the outside of the base foil can be increased by increasing the number of through-holes, while a plurality of pressure zones of different pressures between the base foil and the bearing housing can be realized by providing different numbers of through-holes at different circumferential positions within one groove. While different pressure zones may form wedge gaps of different sizes. Referring to fig. 10B, the first, second and third through hole groups 313a, 313B, 313c correspond to a low pressure region, a medium pressure region and a high pressure region, respectively, along the rotation direction ω of the rotor 10, and the wedge gap formed between the rotor 10 and the top foil 34 may be varied by the air pressure of these pressure regions.

The low pressure zone may form a wedge-shaped gap X3 between the rotor 10 and the top foil 34, the medium pressure zone may form a wedge-shaped gap X2 between the rotor 10 and the top foil 34, and the high pressure zone may form a wedge-shaped gap X1 between the rotor 10 and the top foil 34. Here, the wedge gap X1 is smaller than the wedge gap X2, and the wedge gap X2 is smaller than the wedge gap X3. This achieves the effect that the wedge gap decreases from large to small in the direction of rotation omega of the rotor 10. This allows the gas bearing to form a hydrodynamic gas film more quickly during the start-stop or low speed phase of the rotor.

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

Of course, for a designer, the number of through holes and the diameter of the through holes in each through hole group can be correspondingly set according to actual needs to realize the partition of different pressures.

Referring to fig. 5 and 6, in some embodiments, the at least one groove 314 comprises at least two scalloped grooves. For example, in fig. 5, the bearing housing 31 may have three sector-shaped annular grooves. The sector ring shape here refers to a shape of a groove on a cross section of the bearing housing 31, wherein an outer ring of the sector ring is an outer ring of the bearing housing 31, and an inner ring is a bottom of the groove.

In fig. 8, each of the sector annular grooves has two first groove walls 314a opposed in the circumferential direction of the bearing housing 31 and two second groove walls 314b opposed in 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.

Referring to fig. 8, 11A, and 11B, in some embodiments, at least one bottom foil 32 includes a radius 321 and at least three hem panels 322. The circular arc plate 321 has a circular arc-shaped cross section, which is perpendicular to the axis of the gas bearing 30. And at least three folding plates 322 connected to at least three edges of the circular arc plate 321 and extending outward in a radial direction relative to the circular arc plate 321. The inner wall of the bearing housing 31 has at least three insertion grooves 315, and the at least three flange plates 322 are respectively inserted into the at least three insertion grooves 315.

The embedding structure of hem board and embedded groove can realize spacing and mobilizable being connected between end foil and the bearing housing on the one hand, adjusts the interval of arc board for the bearing housing through the gas pressure who acts on at the arc board to utilize the hem board to realize gathering the effect of gas, the partial vibration of the friction consumable rotor of on the other hand hem board and embedded groove when relative motion realizes a part damping of gas bearing.

In fig. 11A and 11B, each bottom foil 32 has two crimping plates 322 disposed opposite to each other in the circumferential direction and one crimping plate 322 disposed in the axial direction, which are respectively fitted into the three fitting grooves 315 of the inner wall of the bearing housing 31, so that the bottom foil 32 forms a gas outflow end open in the axial direction with the inner wall of the bearing housing 31. Thus, the leakage of gas from these three directions is prevented by the three crimping plates, so that a pressure is built up between the bottom foil and the bearing housing, and the gas outflow end promotes the flow of high-pressure gas.

In other embodiments, each bottom foil 32 has two folding plates 322 disposed opposite to each other in the circumferential direction and two folding plates 322 disposed in the axial direction, which are respectively inserted into the four insertion 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. Through the cooperation of four hem boards and four embedded grooves, and improve the static pressure effect, and the static pressure gas can flow out from the clearance of hem board and embedded groove.

Referring to fig. 5 and 6, one end of each bump foil 33 may be connected to the inner wall of the bearing housing 31 by a fixing pin and a second pin hole line groove 312 at the inner wall of the bearing housing 31. In some embodiments, the top foil 34 comprises 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 facing away from the bearing housing 31, radially supporting the at least one bump foil 33. The second top foil 342 is located on a side of the first top foil 341 facing away from the bearing housing 31, radially supporting the first top foil 341. 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 slot 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 the opposite direction.

By arranging the first top foil and the second top foil which extend in opposite directions, relative motion can be generated between the two top foils when the rotor rotates, and then friction is generated, and the friction can consume part of the vibration of the rotor to form part of damping of the gas bearing.

Referring to fig. 1-4, in some embodiments, the bearing assembly further includes a rotor amplitude detection unit. The rotor amplitude detection unit is disposed on the bearing support 20 and located on one side of the gas bearing 30 in 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 when the rotor rotates. And the air vent 21 may be connected to an external air supply device, and an amount of air supplied received by the air vent may be adjusted according to the amplitude.

In fig. 1 to 4, the rotor amplitude detecting unit includes at least two eddy current displacement sensors 40. At least two eddy current displacement sensors 40 are distributed at different angular positions along the circumference of the gas bearing 30. The eddy current displacement sensor 40 is fixed to the bearing holder 20 by, for example, screwing.

In order to reduce the number of sensors, it is preferable that the rotor amplitude detection unit includes two eddy current displacement sensors 40 that are different by 90 degrees in the circumferential direction of the gas bearing 30. The initial position of the rotor 10 may be detected by the two eddy current displacement sensors 40 while the rotor 10 is in a stationary state. When the rotor 10 rotates, under the action of different rotating speeds and external forces, the vibration amplitudes of the rotor are different, and through comparison with the initial position, the measured vibration amplitude of the rotor can reflect the position of the rotor in real time on one hand, and on the other hand, whether the gas film thickness of the rotor is proper or not can be fed back. The proper film thickness allows the rotor to have a small and stable amplitude.

In the foregoing, it is mentioned that different wedge gaps corresponding to different pressure regions are realized through a plurality of through hole groups, and the variation of each wedge gap is more obvious and the difference is increased along with the increase of the pressure of the high-pressure gas introduced to the outer side of the bottom foil. And the difference of the wedge-shaped gaps can be reduced along with the reduction of the pressure of the high-pressure gas introduced to the outer side of the bottom foil. Therefore, the static pressure can be adjusted by controlling the high-pressure gas entering the pressure cavity, so that the wedge-shaped gap is adjusted, dynamic pressure gas films with different thicknesses are formed, and the bearing can adapt to the change of working conditions and provide corresponding bearing capacity.

For example, when the rotor rotates at a high speed, the rotor needs a larger bearing supporting force, the bearing supporting force can be provided by reducing the thickness of the dynamic pressure gas film, the pressure of the introduced high-pressure gas is reduced, so that the difference between the wedge gaps (such as the wedge gaps X3, X2 and X1) corresponding to each pressure area becomes smaller, and 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.

The embodiments of the bearing assembly described above can be applied to various kinds of apparatuses having a rotor, such as a compressor. Accordingly, the present disclosure also provides a compressor comprising any of the embodiments of the bearing assembly described above.

Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the disclosure. The scope of the present disclosure is defined by the appended claims.

Claims (16)

1. A gas bearing (30), comprising:

a bearing housing (31) having at least one groove (314) on an outer peripheral surface thereof configured to form a pressure chamber (316);

at least one bottom foil (32) disposed inside an inner circumferential surface of the bearing housing (31) and corresponding to the at least one groove (314), respectively;

at least one bump foil (33) respectively arranged on one side of the at least one bottom foil (32) far away from the bearing shell (31) and respectively corresponding to the at least one groove (314);

a top foil (34) arranged on a side of the at least one bump foil (33) facing away from the bearing housing (31),

wherein a groove bottom of the at least one groove (314) has a plurality of through holes (313), the plurality of through holes (313) being configured to let pressure gas within the pressure chamber (316) enter between the bearing housing (31) and the corresponding bottom foil (32) and act on a surface of the bottom foil (32).

2. The gas bearing (30) of claim 1, wherein the at least one groove (314) comprises a plurality of grooves (314) spaced circumferentially along the bearing housing (31).

3. The gas bearing (30) of claim 1, wherein the plurality of through holes (313) comprises at least two through hole groups distributed along a circumferential direction of the bearing housing (31) and configured to gradually increase in pressure along a rotational direction (ω) of a rotor (10) supported by the gas bearing (30).

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

5. The gas bearing (30) according to claim 4, wherein 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 in a circumferential direction of the bearing housing (31), the first through hole group (313a), the second through hole group (313b), and the third through hole group (313c) respectively include a plurality of through holes (313) having the same diameter, and the number of through holes of the first through hole group (313a) is smaller than the number of through holes of the second through hole group (313b), and the number of through holes of the second through hole group (313) is smaller than the number of through holes of the third through hole group (313 c).

6. The gas bearing (30) of claim 1, wherein the at least one groove (314) comprises at least two sector-shaped annular grooves, each sector-shaped annular groove having two first groove walls (314a) opposing in a circumferential direction of the bearing housing (31) and two second groove walls (314b) opposing in an axial direction of the bearing housing (31).

7. Gas bearing (30) according to claim 1, wherein the at least one bottom foil (32) comprises:

the cross section of the arc plate (321) is arc-shaped;

at least three flange plates (322) connected to at least three edges of the circular arc plate (321) and extending outward in a radial direction with respect to the circular arc plate (321),

wherein the inner wall of the bearing housing (31) is provided with at least three embedded grooves (315), and the at least three folding plates (322) are respectively embedded in the at least three embedded grooves (315).

8. Gas bearing (30) according to claim 7, wherein each bottom foil (32) has two crimping plates (322) arranged opposite to each other in the circumferential direction and one crimping plate (322) arranged in the axial direction, respectively embedded in three embedding grooves (315) of the inner wall of the bearing housing (31), such that the bottom foil (32) forms an axially open gas outflow end with the inner wall of the bearing housing (31).

9. The gas bearing (30) as claimed in claim 7, wherein each bottom foil (32) has two folding plates (322) arranged opposite in the circumferential direction and two folding plates (322) arranged in the axial direction, which are respectively inserted into four insertion grooves (315) of the inner wall of the bearing housing (31) so that the bottom foil (32) forms a closed gas chamber with the inner wall of the bearing housing (31).

10. The gas bearing (30) of claim 1, wherein the top foil (34) comprises:

a first top foil (341) located on a side of the at least one bump foil (33) remote from the bearing housing (31) radially supporting the at least one bump foil (33);

a second top foil (342) on a side of the first top foil (341) facing away from the bearing housing (31) radially supporting the first top foil (341),

wherein the first end of the first top foil (341) and the first end of the second top foil (342) are connected with the inner wall of the bearing housing (31) through a fixed pin and a first pin hole line groove (311) positioned 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 the opposite direction.

11. A bearing assembly, comprising:

a bearing support (20) having a cavity and a vent hole (21) communicating with the cavity;

the gas bearing (30) of any of claims 1 to 10, located within the cavity,

wherein the at least one groove (314) of the bearing housing (31) forms a pressure chamber (316) with a wall of the cavity.

12. A bearing assembly according to claim 11, characterized in that the bearing housing (31) outer wall is a radially interference fit with the cavity.

13. The bearing assembly of claim 11, further comprising:

a rotor amplitude detection unit provided on the bearing holder (20) and located on one side of the gas bearing (30) in an axial direction of the gas bearing (30), configured to detect an amplitude of a rotor (10) supported by the gas bearing (30) when rotating,

wherein the vent hole (21) is configured to be connected to an external air supply device, and the amount of air supplied to be received is adjusted according to the amplitude.

14. The bearing assembly of claim 13, wherein the rotor amplitude detection unit comprises:

at least two eddy current displacement sensors (40) distributed at different angular positions along the circumference of the gas bearing (30).

15. A 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, comprising:

a bearing assembly according to any of claims 11 to 15.

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