CN114688159A

CN114688159A - Gas bearing assembly and compressor

Info

Publication number: CN114688159A
Application number: CN202011566527.2A
Authority: CN
Inventors: 董明珠; 刘华; 张治平; 雷连冬
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2022-07-01

Abstract

The present disclosure relates to a gas bearing assembly and a compressor. The gas bearing assembly includes: a first rotor (10) comprising an air reservoir (11) located inside the first rotor (10) and a throttling structure (12) located radially outside the air reservoir (11), the air reservoir (11) being configured to convey static pressure gas through the throttling structure (12) to outside the throttling structure (12); the bearing shell (20) is sleeved on the outer peripheral surface of the first rotor (10) and is provided with a static pressure radial bearing section (21) and a dynamic pressure radial bearing section (22) which are arranged along the axial direction, wherein the length ranges of the throttling structure (12) and the static pressure radial bearing section (21) in the axial direction are at least partially overlapped, and the distance between a static pressure matching surface of the throttling structure (12) and the static pressure radial bearing section (21) is smaller than the distance between the first rotor (10) and the dynamic pressure radial bearing section (22). The embodiment of the disclosure can avoid collision of the gas bearing with the rotor during operation as much as possible.

Description

Gas bearing assembly and compressor

Technical Field

The disclosure relates to the field of bearings, and in particular relates to a gas 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 produced 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 hydrodynamic pressure effect, static pressure effect and squeezing effect during friction.

Gas bearings can be classified into hydrodynamic gas bearings, hydrostatic gas bearings, and squeeze 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 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 film force is sufficient to balance the shaft load, the shaft is completely separated from the bearing, and the process of film generation 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 by the bearing restrictor and the 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

The inventors have found through studies that the bearing stiffness of the gas bearing in the related art is much lower than that of the oil bearing, so that the rotor-bearing system using the gas bearing often runs transcritically. When the rotor speed is near the modes (e.g., first and second order modes), the rotor is susceptible to resonance. When the rotor amplitude is too large to be larger than the bearing gap, it will cause the bearing to collide with the rotor.

In view of this, embodiments of the present disclosure provide a gas bearing assembly and a compressor, which can avoid collision between the gas bearing and a rotor during operation as much as possible.

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

a first rotor comprising a gas storage cavity inside the first rotor and a throttling structure radially outside the gas storage cavity, the gas storage cavity being configured to convey static pressure gas through the throttling structure outside the throttling structure;

a bearing housing which is sleeved on the peripheral surface of the first rotor and is provided with at least one static pressure radial bearing section and at least one dynamic pressure radial bearing section which are arranged along the axial direction,

the length range of the throttling structure and the length range of the at least one static pressure radial bearing section in the axial direction are at least partially overlapped, and the distance between a static pressure matching surface of the throttling structure and the at least one static pressure radial bearing section is smaller than the distance between the first rotor and the at least one dynamic pressure radial bearing section.

In some embodiments, the first rotor further comprises:

the air inlet cavity is positioned at one end of the first rotor in the axial direction and is communicated with the air storage cavity in the first rotor;

and the assembling part is positioned at the other end of the first rotor in the axial direction and is configured to be fixedly connected with a second rotor which is coaxial with the first rotor.

In some embodiments, the first rotor further comprises:

the axial flow fan blades are circumferentially arranged on the inner wall of the air inlet cavity and are configured to suck airflow outside the first rotor into the air inlet cavity when the first rotor rotates.

In some embodiments, a partition wall is arranged between the air inlet cavity and the air storage cavity, and an air inlet hole is arranged on the partition wall.

In some embodiments, the air intake hole is located at the center of the partition wall, and the axis of the first rotor passes through the air intake hole.

In some embodiments, a surface of the partition wall adjacent to a side of the intake chamber is tapered and recessed toward the intake aperture.

In some embodiments, the air intake chamber and the air reservoir chamber each comprise a cylindrical hollow portion.

In some embodiments, the fitting portion includes:

and the assembly cavity is positioned in the first rotor, is communicated with the air storage cavity, is configured to accommodate the end part of the second rotor and is in interference fit with the end part of the second rotor.

In some embodiments, the throttling structure comprises a first annular housing having a plurality of static pressure micro holes respectively penetrating through a solid portion of the first annular housing to communicate the air reservoir with the outside of the static pressure mating surface, and the at least one static pressure radial bearing section comprises a second annular housing, and the distance between the static pressure mating surface of the throttling structure and the at least one static pressure radial bearing section is equal to the distance between the outer wall of the first annular housing and the inner wall of the second annular housing.

In some embodiments, the plurality of static pressure micro-holes are arranged in a circumferential and axial array along the first annular housing.

In some embodiments, the throttling structure comprises a ring of porous material, or the throttling structure comprises an annular housing and a plurality of blocks of porous material circumferentially spaced apart on the annular housing.

In some embodiments, the at least one hydrodynamic radial bearing segment comprises two hydrodynamic radial bearing segments axially disposed on opposite sides of the at least one hydrostatic radial bearing segment.

In some embodiments, each hydrodynamic radial bearing segment comprises:

a third annular housing axially connected to the second annular housing;

the supporting bump foils are connected with the inner wall of the third annular shell, each supporting bump foil is integrally in a circular arc shape, and a plurality of arc-shaped ripples are arranged along the extending direction of the supporting bump foils;

a top foil connected to an inner wall of the third annular housing and located on a side of the wave foil remote from the third annular housing, configured to support the supporting wave foil in a radial direction,

wherein a distance between the first rotor and the at least one dynamic pressure radial bearing section is a distance between an outer circumferential surface of the first rotor and an inner circumferential surface of the top foil.

In some embodiments, the outer circumferential diameter of the first annular housing is greater than the outer circumferential diameter of the other portion of the first rotor.

In some embodiments, the gas bearing assembly further comprises:

and the second rotor is coaxial with the first rotor and is fixedly connected with the assembling part of the first rotor.

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

Therefore, according to the embodiment of the disclosure, the air storage cavity is arranged in the rotor, so that the air storage cavity conveys the static pressure air to the static pressure radial bearing section of the bearing housing through the throttling structure, and the distance between the throttling structure and the static pressure radial bearing section is smaller than the distance between the rotor and the dynamic pressure radial bearing section. Therefore, the dynamic pressure radial bearing section in the gas bearing assembly of the embodiment of the disclosure can form a dynamic pressure gas film with the rotor to support the rotor to rotate when the rotor reaches the designed rotating speed, and the static pressure gas exhausted by the gas storage cavity and the throttling structure can flow to the gap of the dynamic pressure radial bearing section, which is called as a gas source for forming the dynamic pressure gas film; when the rotating speed of the rotor is close to a critical mode, the amplitude of the rotor is increased due to resonance, and when the rotating speed of the rotor is close to a gap of a static pressure radial bearing section, a static pressure gas film can participate in supporting the rotor, so that extra supporting force is provided, the vibration of the rotor is restrained, and the collision of the gas bearing and the rotor during operation can be avoided as much as possible.

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, partially in section, of a mounting structure according to some embodiments of a gas bearing assembly of the present disclosure;

FIG. 2 is a longitudinal cross-sectional schematic view of the mounting structure of FIG. 1;

FIG. 3 is a schematic view of the structure at view A in FIG. 2;

FIG. 4 is a schematic diagram of the structure at view B in FIG. 2;

FIG. 5 is an enlarged partial schematic view of the portion indicated by circle I in FIG. 3;

FIG. 6 is a schematic view of a mounting arrangement of a first rotor and a second rotor in some embodiments of a gas bearing assembly according to the present disclosure;

FIG. 7 is a longitudinal cross-sectional schematic view of the mounting structure of FIG. 6;

FIG. 8 is a schematic structural view of a bearing housing in accordance with some embodiments of the gas bearing assembly of the present disclosure;

fig. 9 is a longitudinal sectional view of fig. 8.

It should be understood that the dimensions of the various parts shown in the figures are not drawn to scale. 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: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not as limitative, unless specifically stated otherwise.

The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather are 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 a specific device is described as being located between a first device and a second device, there may or may not be intervening devices 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.

Referring to fig. 1-9, in some embodiments, the present disclosure provides a gas bearing assembly. The gas bearing assembly includes: a first rotor 10 and a bearing housing 20. The first rotor 10 comprises an air reservoir 11 located inside said first rotor 10 and a throttle structure 12 located radially outside said air reservoir 11, said air reservoir 11 being configured to convey the static pressure gas through said throttle structure 12 to the outside of said throttle structure 12.

The bearing housing 20 is fitted over the outer circumferential surface of the first rotor 10, and has at least one hydrostatic radial bearing section 21 and at least one hydrodynamic radial bearing section 22 arranged in the axial direction. The throttle structure 12 at least partially coincides with the axial extent of the at least one hydrostatic radial bearing segment 21. In fig. 1 and 2, the axial length extent of the throttle structure 12 substantially completely coincides with the axial length extent of the hydrostatic radial bearing segment 21. In other embodiments, the axial length ranges of the two may be offset from each other by a fraction and remain partially coincident, or the axial length ranges of one of the two may comprise the axial length range of the other.

The gas in the gas storage chamber 11 is from the outside of the first rotor 10, and after passing through the throttling structure 12 and entering the gap between the bearing housing 20 and the throttling structure 12, can flow into the dynamic pressure radial bearing section 22 so as to provide a gas source for forming a dynamic pressure gas film to the dynamic pressure gap.

The distance θ 1 between the static pressure mating surface of the throttle structure 12 and the at least one static pressure radial bearing section 21 is smaller than the distance θ 2 between the first rotor 10 and the at least one dynamic pressure radial bearing section 22. Thus, the dynamic pressure radial bearing section in the gas bearing assembly of the present embodiment can form a dynamic pressure gas film with the rotor to support the rotor to rotate when the rotor reaches the designed rotation speed, and the static pressure gas exhausted through the gas storage cavity and the throttling structure can flow to the gap of the dynamic pressure radial bearing section, which is called as a gas source for forming the dynamic pressure gas film. When the rotor speed is near a critical mode (such as a first-order mode or a second-order mode), the rotor amplitude is increased due to resonance, and when the clearance of the static pressure radial bearing section is approached, the static pressure air film can participate in supporting the rotor to provide an additional supporting force and restrain the vibration of the rotor.

Referring to fig. 1, 2, 6, and 7, in some embodiments, the first rotor 10 further comprises: an inlet chamber 13 and a fitting 15. The air inlet chamber 13 is located at one end of the first rotor 10 in the axial direction and communicates with the air storage chamber 11 inside the first rotor 10. The gas entering the inlet chamber 13 may be driven from a gas drive means either external to the rotor or internal to the rotor. For example, an intake pipe for charging the intake chamber 13 with high-pressure gas is provided at an end portion of the first rotor 10, or a structure capable of sucking external gas, such as a fan blade, is provided at an end portion of the first rotor 10.

The fitting portion 15 is located at the other end of the first rotor 10 in the axial direction, and is configured to fixedly connect to a second rotor 30 coaxial with the first rotor 10. Fig. 1 and 2 only show a portion of the length of the second rotor 30. The second rotor 30 may be part of the gas bearing assembly or may be provided separately from the gas bearing assembly. The fitting portion 15 and the second rotor 30 may be fixed by various connection means, such as interference fit by shrink fit, adhesion, screw connection, welding, and the like.

Because the gas storage cavity is located inside the first rotor, the assembly portion is arranged to facilitate processing of the gas storage cavity and the throttling structure of the first rotor. In other words, the air reservoir and the throttle structure are machined on the mounting part side before the mounting part is connected to the second rotor. In other embodiments, the mounting portions on the second rotor and the first rotor may be omitted by forming the air reservoir and the throttle structure in other ways.

Referring to fig. 2-7, in some embodiments, the first rotor 10 further includes a plurality of axial flow fan blades 14. The axial flow fan blades 14 are circumferentially located on an inner wall of the air intake cavity 13, and are configured to suck an air flow outside the first rotor 10 into the air intake cavity 13 when the first rotor 10 rotates.

In operation, the first rotor 10 and the second rotor 30 can rotate at high speed in the rotation directions shown by arrows in fig. 3 and 4 respectively under the driving action (e.g. electromagnetic field action), and the axial flow fan blades 14 rotate synchronously with the first rotor 10 to suck the gas on the left side of the first rotor 10 into the gas inlet cavity 13 continuously and then into the gas storage cavity 11, so that the gas pressure in the gas storage cavity 11 is increased. The gas in the gas storage cavity 11 reaches the static pressure matching surface outside the throttling structure 12 through the throttling structure 12 to form a static pressure gas supporting effect.

Compared with the air supply mode from the outer side of the bearing shell in the related art, the air supply mode realized by the embodiment greatly simplifies the structure of the static pressure air supply system, and omits an air supply pump, an air supply pipe, a corresponding pipe joint and the like.

Referring to fig. 1, 2 and 7, in some embodiments, the air inlet chamber 13 and the air storage chamber 11 have a partition wall 131 therebetween, and an air inlet hole 132 is formed on the partition wall 131. The axial flow blades 14 may extend from the inlet of the intake chamber 13 to the partition wall 131 or a position adjacent to the partition wall 131. In some embodiments, the air intake hole 132 is located at the center of the partition wall 131, and the axis of the first rotor 10 passes through the air intake hole 132. This is advantageous in that the air stream entering is prevented from additional centrifugal force caused by the eccentrically entering air stream.

In fig. 2 and 7, the surface of the partition wall 131 adjacent to the side of the intake chamber 13 is tapered and concaved toward the intake hole 132. The partition wall can realize the flow guiding function of the gas, guide the gas to transit from the axial flow fan blade to the gas inlet in the gas inlet cavity, improve the uniformity of a flow field and avoid generating noise at high rotating speed.

Referring to fig. 1 and 6, the air intake chamber 13 and the air reservoir chamber 11 each include a cylindrical hollow portion, which facilitates more uniform air intake and air discharge through the throttle structure 12. In other embodiments, the air inlet chamber 13 and the air reservoir chamber 11 may also comprise hollow portions of other shapes, such as prisms, cones, etc.

Referring to fig. 7, in some embodiments, the fitting 15 includes a fitting cavity 151. The fitting cavity 151 is located inside the first rotor 10, communicates with the air storage cavity 11, is configured to receive an end portion of the second rotor 30, and is in interference fit with an end portion of the second rotor 30. The assembly chamber 151 may include a cylindrical hollow portion to facilitate machining. In other embodiments, prismatic hollow portions may also be included to better transmit torque. The assembly chamber 151 may be formed prior to the air reservoir chamber 11 so that a machining tool may machine the air reservoir chamber 11 through the assembly chamber 151. In other embodiments, the mounting cavity and the air reservoir cavity may be formed together by integral molding.

Referring to fig. 6 and 7, in some embodiments, the throttling structure 12 includes a first annular housing 122, and the first annular housing 122 has a plurality of static pressure micro holes 121, and the plurality of static pressure micro holes 121 respectively penetrate through solid portions of the first annular housing 122 to communicate the air storage chamber 11 with the outside of the static pressure mating surface. Referring to fig. 2 and 8, the at least one hydrostatic radial bearing segment 21 includes a second annular housing 211. The distance θ 1 between the static pressure mating surface of the throttling structure 12 and the at least one static pressure radial bearing section 21 is the distance θ 1 between the outer wall of the first annular housing 122 and the inner wall of the second annular housing 211.

In fig. 6 and 7, the plurality of static pressure micro-holes 121 are arranged in a circumferential and axial array along the first annular housing 122. The row pitch and column pitch in the array can be the same. The size and number of static micropores 121 may be selected according to the static pressure requirements. The shape of the static pressure minute hole 121 is preferably a circular cross section, and may be an elliptical cross section or a polygonal cross section. The pore diameter of the static pressure micropores 121 with a circular cross section is 10 to 50 micrometers, for example, 20 micrometers in terms of size.

In other embodiments, other forms of the flow restriction structure 12 may be used, such as where the flow restriction structure 12 comprises a ring of porous material. The porous material ring may be a ring body formed of a porous graphite material. Alternatively, the throttle structure 12 includes an annular housing and a plurality of porous material blocks arranged on the annular housing at intervals in the circumferential direction. The porous material block may be a block made of a porous graphite material.

No matter what type of throttling structure is adopted, the sum of the pore diameters of the pore passages or pores with the throttling function is far smaller than the diameter of the air inlet hole, so that the air pressure in the air storage cavity can be effectively increased. And the high-pressure gas reaches the static pressure matching surface after passing through the throttling function of the throttling structure, and the rotor can be supported by the static pressure gas.

Besides supporting the rotor, the gas reaching the static pressure matching surface partially presses between the radial bearing section and the rotor along the axial flow channel, so that the supported gas source is pressed. And like this also can clear up the impurity of dynamic pressure radial bearing section, avoid the impurity accumulation, reduce the wearing and tearing of impurity accumulation to dynamic pressure radial bearing section.

Referring to fig. 1-5 and 8-9, in some embodiments, the at least one hydrodynamic radial bearing segment 22 includes two hydrodynamic radial bearing segments 22 axially disposed on either side of the at least one hydrostatic radial bearing segment 21. The bearing balance of each segment of the gas bearing assembly on the rotor in the axial direction is facilitated, and the risk of inclination of the rotor in operation is reduced. In other embodiments, the hydrodynamic radial bearing segments may be provided on only one side of the hydrostatic radial bearing segments to reduce the size of the bearing.

Referring to fig. 3-5, in some embodiments, each hydrodynamic radial bearing segment 22 includes: a third annular housing 221, at least one supporting bump foil 222 and a top foil 223. The third annular housing 221 is axially connected to said second annular housing 211. At least one supporting bump 222 is attached to the inner wall of said third annular housing 221. In fig. 3 and 4, the hydrodynamic radial bearing segment 22 includes three supporting bump foils 222. Each support bump 222 is shaped like an arc as a whole, and has a plurality of arc-shaped ripples along the extending direction of the support bump 222. A top foil 223 is connected to the inner wall of the third annular housing 221, on the side of the wave foil remote from the third annular housing 221, and is configured to support the supporting wave foil 222 in a radial direction. The distance θ 2 between the first rotor 10 and the at least one hydrodynamic radial bearing segment 22 is the distance θ 2 between the outer circumferential surface of the first rotor 10 and the inner circumferential surface of the top foil 223.

At least one mounting slit 224 may be provided at an inner wall of the third casing 221, and one ends of the top foil 223 and the bump foil 222 may be fixed in the mounting slit 224 by a fixing pin 225. In the related art, the rotor supported by the dynamic pressure wave foil gas bearing needs to be rotated in a direction from the free end to the fixed end of the supporting wave foil in order to put the supporting wave foil in a "taut" state, which would otherwise cause the bearing to fail. The embodiment allows the rotor to rotate reversely, because the static pressure air film formed by the static pressure radial bearing section and the rotor can support the rotor when the rotor rotates reversely, so that the rotor is protected.

Referring to fig. 5-7, in some embodiments, the outer circumferential diameter of the first annular housing 122 is greater than the outer circumferential diameter of other portions of the first rotor 10. I.e. a step 16 is formed at the location of the first annular housing 122. From fig. 5, it can be seen that a spacing θ 1 is formed between the larger diameter outer periphery of the first rotor and the bearing housing, while a spacing θ 2 is formed between the smaller diameter outer periphery of the first rotor and the top foil. Such a structure of the first rotor is advantageous in forming the effect of θ 1< θ 2.

In the above embodiment, the bearing housing may be manufactured by casting or machining, etc., and the supporting bump foil and the top foil are assembled on the bearing housing. The first rotor may be made by casting or machining, etc. For embodiments employing a ring or block of porous material, the ring or block of porous material may be assembled to the first rotor.

The embodiments of the gas bearing assembly described above may be applied to various types of equipment or facilities that require support of a rotor, such as a compressor. Accordingly, embodiments of the present disclosure also provide a compressor including any of the embodiments of the gas bearing assembly described above.

Referring to fig. 1-9, when the rotor is normally operated to a certain rotation speed, the hydrodynamic radial bearing section may support the rotor through a hydrodynamic gas film formed by the top foil and the surface of the rotor. The strength of the dynamic pressure air film is positively correlated with the rotating speed, and the dynamic pressure radial bearing section provides main bearing capacity under the high-speed condition. However, when the rotational speed of the rotor is operated near the critical mode, the rotor amplitude inevitably increases due to resonance. When the amplitude of the vibration approaches the spacing theta 1 of the static pressure radial bearing sections, the static pressure air film formed on the surface of the throttling structure participates in supporting the rotor and provides additional bearing capacity, and the vibration of the rotor is restrained. When the rotor operates at a high speed (the speed is more than 15000rpm), the bearing capacity required by the rotor is larger, and in addition, the required bearing capacity is increased suddenly sometimes due to airflow impact caused by an operating environment, the bearing capacity of a dynamic pressure radial bearing section is insufficient, the thickness of a dynamic pressure air film is reduced, and the static pressure air film also participates in and provides additional bearing capacity to support the rotor.

Thus far, 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 present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A gas bearing assembly, comprising:

a first rotor (10) comprising an air reservoir (11) located inside the first rotor (10) and a throttling structure (12) located radially outside the air reservoir (11), the air reservoir (11) being configured to convey static pressure gas through the throttling structure (12) to outside the throttling structure (12);

a bearing housing (20) which is sleeved on the outer peripheral surface of the first rotor (10) and is provided with at least one static pressure radial bearing section (21) and at least one dynamic pressure radial bearing section (22) which are arranged along the axial direction,

wherein the length range of the throttling structure (12) and the at least one static pressure radial bearing section (21) in the axial direction at least partially coincide, and the distance between a static pressure matching surface of the throttling structure (12) and the at least one static pressure radial bearing section (21) is smaller than the distance between the first rotor (10) and the at least one dynamic pressure radial bearing section (22).

2. A gas bearing assembly according to claim 1, characterized in that the first rotor (10) further comprises:

the air inlet cavity (13) is positioned at one end of the first rotor (10) along the axial direction and is communicated with the air storage cavity (11) inside the first rotor (10);

and a fitting part (15) located at the other end of the first rotor (10) in the axial direction and configured to fixedly connect a second rotor (30) coaxial with the first rotor (10).

3. A gas bearing assembly according to claim 2, characterized in that the first rotor (10) further comprises:

the axial-flow fan blades (14) are circumferentially arranged on the inner wall of the air inlet cavity (13) and are configured to suck airflow outside the first rotor (10) into the air inlet cavity (13) when the first rotor (10) rotates.

4. A gas bearing assembly according to claim 2 or 3, characterized in that between the air intake cavity (13) and the air reservoir cavity (11) there is a partition wall (131), on which partition wall (131) there is an air intake hole (132).

5. A gas bearing assembly according to claim 4, characterized in that the gas inlet hole (132) is located in the centre of the partition wall (131), the axis of the first rotor (10) passing through the gas inlet hole (132).

6. A gas bearing assembly according to claim 4, characterised in that the surface of the partition wall (131) on the side adjacent to the inlet chamber (13) is conical and is concave towards the inlet aperture (132).

7. A gas bearing assembly according to claim 2, characterized in that the gas inlet cavity (13) and the gas reservoir cavity (11) each comprise a cylindrical hollow portion.

8. A gas bearing assembly according to claim 2, characterized in that the fitting part (15) comprises:

a fitting cavity (151) located inside the first rotor (10), communicating with the air storage cavity (11), configured to receive an end of the second rotor (30) and to be in interference fit with an end of the second rotor (30).

9. A gas bearing assembly according to claim 1, characterized in that the throttle structure (12) comprises a first annular housing (122), the first annular housing (122) having a plurality of static pressure micro holes (121), the plurality of static pressure micro holes (121) respectively penetrating a solid portion of the first annular housing (122) to communicate the air reservoir chamber (11) with an outside of the static pressure mating face, the at least one static pressure radial bearing section (21) comprising a second annular housing (211), the static pressure mating face of the throttle structure (12) being spaced from the at least one static pressure radial bearing section (21) by a spacing of an outer wall of the first annular housing (122) from an inner wall of the second annular housing (211).

10. A gas bearing assembly according to claim 9, characterized in that said plurality of static pressure micro-holes (121) are arranged in a circumferential and axial array along said first annular housing (122).

11. A gas bearing assembly according to claim 1, characterized in that the throttle structure (12) comprises a ring of porous material, or the throttle structure (12) comprises an annular housing and a plurality of blocks of porous material arranged circumferentially spaced on the annular housing.

12. A gas bearing assembly according to claim 1, characterized in that the at least one hydrodynamic radial bearing section (22) comprises two hydrodynamic radial bearing sections (22) axially on both sides of the at least one hydrostatic radial bearing section (21).

13. A gas bearing assembly according to claim 9, characterized in that each hydrodynamic radial bearing segment (22) comprises:

a third annular housing (221) axially connected to the second annular housing (211);

at least one supporting wave foil (222) connected with the inner wall of the third annular shell (221), wherein each supporting wave foil (222) is in an arc shape as a whole and is provided with a plurality of arc-shaped ripples along the extending direction of the supporting wave foil (222);

a top foil (223) connected to an inner wall of the third annular housing (221) and located on a side of the wave foil remote from the third annular housing (221), configured to support the supporting wave foil (222) in a radial direction,

wherein the distance between the first rotor (10) and the at least one hydrodynamic radial bearing section (22) is the distance between the outer circumferential surface of the first rotor (10) and the inner circumferential surface of the top foil (223).

14. A gas bearing assembly according to claim 9, characterized in that the outer diameter of the first annular housing (122) is larger than the outer diameter of the rest of the first rotor (10).

15. A gas bearing assembly according to claim 2, further comprising:

and a second rotor (30) which is coaxial with the first rotor (10) and is fixedly connected with the assembling part (15) of the first rotor (10).

16. A compressor, comprising:

a gas bearing assembly according to any of claims 1 to 15.