Hydrodynamic gas bearing

Abstract

The present application relates to the technical field of gas bearings, and provides a hydrodynamic gas bearing, which includes a bearing sleeve, a top foil installed in the bearing sleeve and used to form a gas film gap with a rotor, and at least two support foil pieces circumferentially spaced apart and supported between the bearing sleeve and the top foil; both ends of the top foil are respectively installed on the bearing sleeve; the support foil pieces are in a flat sheet structure, one end of the support foil piece along the circumference after bending is installed on the bearing sleeve, and the other end is suspended; a plurality of sliding beams are formed by hollowing out on the support foil piece, the sliding beams have two sliding ends, and each sliding end can be supported on the inner wall of the bearing sleeve and slide on the inner wall of the bearing sleeve after the support foil piece is bent. For the hydrodynamic gas bearing of the present application, one end of the support foil piece is fixed and the other end is suspended after being bent and installed. Due to elastic deformation, the support foil piece has a pre-tightening force on the top foil, and this pre-tightening force improves the stiffness and damping characteristics of the support foil piece, and improves the stiffness and load-bearing capacity of the entire hydrodynamic gas bearing.

Description

Technical Field

[0001] The present application belongs to the technical field of gas bearings, and more specifically, to a hydrodynamic gas bearing. Background Art

[0002] Gas bearings are usually used in high-speed and ultra-high-speed rotating machinery. Their working principle is similar to that of oil film bearings. However, unlike oil film bearings, the bearings and lubricating media of gas bearings are gas. Therefore, the working environment is free of oil pollution and other pollution. Maintenance is relatively simple, and they can adapt to higher temperatures. The operating resistance is extremely small under high-speed conditions. Gas bearings can be divided into two categories: static pressure gas bearings and dynamic pressure gas bearings. Compared with static pressure gas bearings, dynamic pressure gas bearings do not require additional high-pressure gas source, and have the advantages of simple structure and small size. Therefore, dynamic pressure gas bearings are widely used in micro gas turbines, micro turbojet engines and other fields.

[0003] There is a wedge-shaped gap or other special gaps between the hydrodynamic gas bearing and the rotor. When the rotor rotates, gas dynamic pressure is generated in the gap. The hydrodynamic gas bearing includes a bearing sleeve, which generally has an elastic support structure such as a foil structure to improve the stability of the rotor system. When subjected to unstable loads, the foil structure produces relative sliding due to deformation, thereby generating Coulomb friction. However, the structural damping of existing hydrodynamic gas bearings is still insufficient, and the load-bearing capacity and stability of hydrodynamic gas bearings need to be improved. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a hydrodynamic gas bearing to solve the technical problem in the prior art that the load-bearing capacity and stability of the hydrodynamic gas bearing need to be improved.

[0005] To achieve the above-mentioned purpose, the technical solution adopted in the present application is: to provide a hydrodynamic gas bearing, including a bearing sleeve, a top foil installed in the bearing sleeve and used to form an air film gap with a rotor, and at least two supporting foils supported between the bearing sleeve and the top foil and distributed along the circumferential direction; the two ends of the top foil are respectively installed on the bearing sleeve; the supporting foil is a straight sheet structure, and after the supporting foil is bent, one end along the circumferential direction is installed on the bearing sleeve, and the other end is suspended; a plurality of sliding beams are hollowed out on the supporting foil, and the sliding beam has two sliding ends, and each of the sliding ends can be supported on the inner wall of the bearing sleeve and slide on the inner wall of the bearing sleeve after the supporting foil is bent.

[0006] In a possible embodiment, each of the sliding beams is distributed along a first direction and a second direction respectively, the first direction is set to the axial direction of the supporting foil after installation, and the second direction is set to the circumferential direction of the supporting foil after installation;

[0007] The sliding beam includes a connecting arm and two sliding arms. The two sliding arms are symmetrically arranged on both sides of the connecting arm along the second direction. One end of each sliding arm is connected to the connecting arm, and the other end of the sliding arm is the sliding end.

[0008] In a possible embodiment, the width of the sliding arm in the first direction gradually increases from the sliding end to the connecting arm.

[0009] Wherein, the sliding arm is trapezoidal or arc-shaped.

[0010] In a possible embodiment, multiple groups of first sliding beam groups are distributed on the supporting foil. Each first sliding beam group is spaced apart along the first direction and the second direction respectively. The first sliding beam group includes at least two sliding beams spaced apart along the first direction. The connecting arms of two adjacent sliding beams in the same first sliding beam group are connected, and the connection part is separated from the supporting foil to form two symmetrically arranged sliding arms.

[0011] In a possible embodiment, multiple groups of second sliding beam groups are distributed on the supporting foil. Each second sliding beam group is spaced apart along the first direction and the second direction respectively. The second sliding beam group includes at least two sliding beams. Among them, at least two sliding beams are respectively a first sliding beam and at least one second sliding beam. The first sliding beam includes two first sliding arms, and the second sliding beam includes two second sliding arms. Each second sliding arm is correspondingly nested in the two first sliding arms.

[0012] In a possible embodiment, the two second sliding arms of the second sliding beam are respectively formed on the two first sliding arms of the first sliding beam. When two or more second sliding beams are formed in the first sliding beam, each second sliding beam is spaced apart along the first direction.

[0013] In a possible embodiment, at least one second sliding beam is distributed on each first sliding arm of the first sliding beam. And when the number of second sliding beams is two or more, each second sliding beam is spaced apart along the first direction.

[0014] In a possible embodiment, the width of the first sliding beam and the width of the second sliding beam in the same group of second sliding beam groups have a first ratio, and the first ratio gradually increases from both sides to the middle along the first direction.

[0015] In a possible embodiment, two adjacent first sliding beams in the first direction are staggered from each other along the second direction and at least partially cross each other.

[0016] In a possible embodiment, in the radial direction of the hydrodynamic gas bearing, the number of layers of the support foil is at least one layer; when the number of layers of the support foil is two or more, the support foils are stacked in sequence from the inside to the outside, and the sliding beams on the support foil located on the inner side sequentially pass through the support foils located outside it and can be supported on the inner wall of the bearing housing and slide on the inner wall of the bearing housing, and the lengths of the sliding beams that are stacked on each other in the support foils decrease sequentially from the inside to the outside in the radial direction.

[0017] The beneficial effects of the hydrodynamic gas bearing provided by this application are as follows: The hydrodynamic gas bearing provided by the embodiments of this application, by distributing at least two support foils between the bearing housing and the top foil, the support foil is in a flat sheet structure, one end of the support foil is fixed after being bent and installed, and the other end is suspended. At the same time, the support foil is set as a support foil with a sliding beam. In this way, after the support foil is installed, due to elastic deformation, it always has a pre-tightening force on the top foil. This pre-tightening force improves the stiffness and damping characteristics of the support foil, thereby improving the stiffness and load-bearing capacity of the entire hydrodynamic gas bearing. In addition, when the hydrodynamic gas bearing bears a load, the load acts on the top foil, and the top foil conducts the force to the support foil. The support foil generates further small deformations, and at the same time, the sliding beam generates bending. The area where the sliding beam contacts the bearing housing increases, and the sliding end of the sliding beam will slide on the inner wall of the bearing housing, forming Coulomb friction damping, further improving the support stability of the hydrodynamic gas bearing to the load. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a three-dimensional schematic diagram of the hydrodynamic gas bearing provided in Embodiment 1 of this application;

[0020] Figure 2 is Figure 1 the axial schematic diagram of the hydrodynamic gas bearing in;

[0021] Figure 3 is Figure 1 the exploded schematic diagram of the hydrodynamic gas bearing in;

[0022] Figure 4 is Figure 1 the structural schematic diagram of the bearing housing in;

[0023] Figure 5 is Figure 1Schematic diagram of the structure of the middle top foil;

[0024] Figure 6 is Figure 1 Schematic diagram of the structure of the middle support foil before assembly;

[0025] Figure 7 is Figure 1 Schematic diagram of the structure of the middle support foil after assembly;

[0026] Figure 8 Schematic diagram of the structure of the support foil provided in the second embodiment of the present application;

[0027] Figure 9 Schematic diagram of the structure of the support foil provided in the third embodiment of the present application;

[0028] Figure 10 Schematic diagram of the structure of the support foil provided in the fourth embodiment of the present application;

[0029] Figure 11 is Figure 10 Schematic diagram of the state where only the first sliding arm of the first sliding beam in the middle abuts against the inner wall of the bearing sleeve;

[0030] Figure 12 is Figure 10 Schematic diagram of the state where both the first sliding arm and the second sliding arm in the middle abut against the inner wall of the bearing sleeve;

[0031] Figure 13 Schematic diagram of the structure of the support foil provided in the fifth embodiment of the present application;

[0032] Figure 14 Schematic diagram of the structure of the support foil provided in the sixth embodiment of the present application;

[0033] Figure 15 Schematic diagram of the state transition of the contact between each sliding beam and the inner wall of the bearing sleeve in the two-layer support foil provided in the seventh embodiment of the present application;

[0034] Figure 16 Schematic diagram of the state transition of the contact between each sliding beam and the inner wall of the bearing sleeve in the three-layer support foil provided in the seventh embodiment of the present application.

[0035] Among them, the reference numerals in the figures:

[0036] 10. Bearing sleeve; 11. First installation groove; 12. Second installation groove; 20. Support foil; 21. Main body frame; 22. First bending part; 23. Sliding beam; 231. Sliding arm; 2311. Sliding end; 232. Connecting arm; M. First sliding beam group; N. Second sliding beam group; 23a. First sliding beam; 23b. Second sliding beam; 231a. First sliding arm; 231b. Second sliding arm; 2311a. First sliding end; 2311b. Second sliding end; 24. Through groove; 30. Top foil; 31. Carrier; 32. Second bending part; X. First direction; Y. Second direction. Detailed implementation manners

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0039] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0040] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0041] Please refer to Figures 1 to 3 , and now the hydrodynamic gas bearing provided by the embodiment of the present application will be described.

[0042] The hydrodynamic gas bearing includes a bearing sleeve 10, a top foil 30, and at least two supporting foil pieces 20 spaced circumferentially. The bearing sleeve 10 is cylindrical. The top foil 30 is installed inside the bearing sleeve 10 and is used to form a gas film gap with the rotor. At least two supporting foil pieces 20 are supported between the bearing sleeve 10 and the top foil 30.

[0043] Both ends of the top foil 30 are respectively installed on the bearing sleeve 10. The supporting foil piece 20 has a flat sheet-like structure. After the supporting foil piece 20 is bent, one end in the circumferential direction is installed on the bearing sleeve 10, and the other end is suspended. A plurality of sliding beams 23 are formed by hollowing out the supporting foil piece 20. That is, the supporting foil piece 20 includes a main body frame 21 and a plurality of sliding beams 23 formed on the main body frame 21. The sliding beam 23 has two sliding ends 2311. After the supporting foil piece 20 is bent, each sliding end 2311 can be supported on the inner wall of the bearing sleeve 10 and slide on the inner wall of the bearing sleeve 10.

[0044] Before installation, the supporting foil piece 20 of the present application has a flat sheet-like structure. After installation, the supporting foil piece 20 is bent by an external force. The main body frame 21 of the supporting foil piece 20 contacts the top foil 30. Due to the elastic deformation of the main body frame 21, the sliding beam 23 is no longer on the curved surface formed by the main body frame 21, but extends from the main body frame 21 in the opposite direction of the bending of the main body frame 21, that is, extends towards the bearing sleeve 10. Then, the sliding ends 2311 of the sliding beam 23 extend from the main body frame 21 towards the bearing sleeve 10 and abut against the inner wall of the bearing sleeve 10. In addition, due to the elastic deformation of the main body frame 21 and one end of the main body frame 21 being suspended, the main body frame 21 does not completely fit the top foil 30 after installation, but has a certain supporting pre-tightening force on the top foil 30. This pre-tightening force enables the supporting foil piece 20 to have a supporting force on the top foil 30 even without a load, thereby providing the stiffness and damping performance of the supporting foil piece 20, and further improving the stiffness and load-carrying capacity of the entire hydrodynamic gas bearing.

[0045] In the hydrodynamic gas bearing of this embodiment, at least two support foil pieces 20 are distributed between the bearing sleeve 10 and the top foil 30. Before installation, the support foil pieces 20 are in a flat sheet structure. After being bent and installed, one end of the support foil piece 20 is fixed and the other end is suspended. At the same time, the support foil piece 20 is configured to have a sliding beam 23. In this way, after the support foil piece 20 is installed, due to elastic deformation, it always has a pre-tightening force on the top foil 30. This pre-tightening force improves the stiffness and damping characteristics of the support foil piece 20, thereby improving the stiffness and load-bearing capacity of the entire hydrodynamic gas bearing. In addition, when the hydrodynamic gas bearing bears a load, the load acts on the top foil 30. The top foil 30 conducts the force to the support foil piece 20, causing the support foil piece 20 to undergo further minor deformation. At the same time, the sliding beam 23 bends, increasing the contact area between the sliding beam 23 and the bearing sleeve 10. And the sliding end 2311 of the sliding beam 23 will slide on the inner wall of the bearing sleeve 10, forming Coulomb friction damping, further improving the support stability of the hydrodynamic gas bearing to the load.

[0046] Please refer to Figures 1 to 3 , the hydrodynamic gas bearing includes a top foil 30 and three support foil pieces 20. The top foil 30 is cylindrical, and both ends of the top foil 30 are respectively installed on the inner wall of the bearing sleeve 10. The three support foil pieces 20 are evenly distributed circumferentially along the bearing sleeve 10 between the bearing sleeve 10 and the top foil 30. After assembly, one end of the support foil piece 20 is installed on the inner wall of the bearing sleeve 10, and the other end is suspended between the bearing sleeve 10 and the top foil 30. It can be understood that in other embodiments of the present application, according to the actual design situation, the number of top foils 30 can also be more than one, and the number of support foil pieces 20 can also be two or more than three, as long as the number of top foils 30 is less than the number of support foil pieces 20 to ensure that the support foil piece 20 can generate sufficient pre-tightening force on the top foil 30 after being bent and assembled, and there is no unique limitation here.

[0047] Please refer to Figure 4 , three first installation grooves 11 and two second installation grooves 12 are provided on the inner wall of the bearing sleeve 10. The three first installation grooves 11 are respectively used to install one end of the three support foil pieces 20, and the two second installation grooves 12 are respectively used to install both ends of the top foil 30. Among them, the number of the first installation grooves 11 can be changed according to the number of the support foil pieces 20, and the number of the second installation grooves 12 can be changed according to the number of the top foils 30.

[0048] Please refer to Figure 4 and Figure 6, the first installation groove 11 is rectangular and axially penetrates through the bearing sleeve 10. The support foil 20 is a flat sheet-like structure extending along the first direction X and the second direction Y respectively. When the support foil 20 is bent and installed into the bearing sleeve 10, the first direction X is the axial direction of the support foil 20, and the second direction Y is the circumferential direction of the support foil 20. One end of the support foil 20 in the first direction X is bent to form a first bending portion 22, and the first bending portion 22 extends along the first direction X. During installation, the first bending portion 22 is axially inserted into the first installation groove 11 to form the connection between the support foil 20 and the bearing sleeve 10.

[0049] Please refer to Figure 4 and Figure 5 , the second installation groove 12 is rectangular and axially penetrates through the bearing sleeve 10. The top foil 30 includes a carrier 31 and two second bending portions 32. The carrier 31 is cylindrical and has an opening formed thereon. The two second bending portions 32 are formed at both ends of the carrier 31 in the circumferential direction, and the second bending portions 32 axially penetrate through the carrier 31. During installation, the second bending portions 32 are axially inserted into the second installation groove 12 to form the connection between the top foil 30 and the bearing sleeve 10.

[0050] Among them, in order to reduce the number of grooves in the bearing sleeve 10, one of the first installation grooves 11 and one of the second installation grooves 12 are combined and arranged. Of course, in other embodiments of the present application, the first installation groove 11 and the second installation groove 12 can also be separately arranged.

[0051] Please refer to Figure 6 , a plurality of through grooves 24 are formed by hollowing out on the support foil 20, and the number of the through grooves 24 is equal to the number of the sliding beams 23. Each sliding beam 23 is formed in one through groove 24.

[0052] In a specific embodiment, please refer to Figure 6 and Figure 7 , each sliding beam 23 is distributed along the first direction X and the second direction Y respectively. The first direction X is set as the axial direction after the support foil 20 is installed, and the second direction Y is set as the circumferential direction after the support foil 20 is installed. The sliding beam 23 includes a connecting arm 232 and two sliding arms 231. The two sliding arms 231 are symmetrically arranged on both sides of the connecting arm 232 in the second direction Y. Both ends of the connecting arm 232 are connecting ends, and both ends of the connecting arm 232 are integrally connected to the inner walls on both sides of the through groove 24 in the first direction X. One end of the sliding arm 231 is connected to the connecting arm 232, and the other end of the sliding arm 231 is the above-mentioned sliding end 2311, that is, the other end of the sliding arm 231 is suspended and can be supported on the inner wall of the bearing sleeve 10 and can slide on the inner wall of the bearing sleeve 10 to form Coulomb friction.

[0053] In a specific embodiment, please refer to Figure 6, the width of the sliding arm 231 in the first direction X gradually increases from the sliding end 2311 to the connecting arm 232, which is beneficial to improving the elasticity and damping characteristics of the sliding end 2311, thereby facilitating the sliding of the sliding end 2311 on the inner wall of the bearing sleeve 10 to generate Coulomb friction.

[0054] Please refer to Figure 6 , the sliding arm 231 is trapezoidal, with a simple structure and convenient processing.

[0055] In a specific embodiment, along the first direction X, the width of the sliding beam 23 gradually increases from both sides to the middle, that is, the sliding beams 23 of the supporting foil 20 at different axial positions have different widths, so that the stiffness of the supporting foil 20 is non-uniformly distributed axially. And since the actual air film pressure of the hydrodynamic gas bearing is also non-uniformly distributed axially, the supporting foil 20 can better adapt to the actual load and has a stronger load-bearing capacity.

[0056] Please refer to Figure 6 , two adjacent sliding beams 23 in the first direction X are staggered from each other in the second direction Y and at least partially cross-set, so that the density of the sliding arm 231 and the sliding end 2311 in the middle area is greater, increasing the Coulomb friction between the inner wall of the corresponding area of the bearing sleeve 10 and the sliding end 2311, thereby improving the stability of the hydrodynamic gas bearing.

[0057] Embodiment 2:

[0058] The essential technical features of the hydrodynamic gas bearing in this embodiment are basically the same as those of the hydrodynamic gas bearing in Embodiment 1, and the difference is that: in this embodiment, please refer to Figure 8 , the above-mentioned sliding arm 231 can also be arc-shaped, and the arc-shaped sliding end 2311 is more conducive to sliding on the inner wall of the bearing sleeve 10 to generate Coulomb friction.

[0059] Similarly, in this embodiment, along the first direction X, the width of the sliding beam 23 can also be designed to gradually increase from both sides to the middle, so that the supporting foil 20 can better adapt to the actual load.

[0060] Embodiment 3:

[0061] The essential technical features of the hydrodynamic gas bearing in this embodiment are basically the same as those of the hydrodynamic gas bearing in Embodiment 1, and the difference is that: in this embodiment, please refer to Figure 9, there are multiple groups of first sliding beam groups M distributed on the supporting foil 20. Each first sliding beam group M is spaced apart along the first direction X and the second direction Y. Specifically, there are three rows of first sliding beam groups M distributed along the first direction X, and four rows of first sliding beam groups M distributed along the second direction Y, for a total of twelve groups of first sliding beam groups M. The first sliding beam group M includes three sliding beams 23 spaced apart along the first direction X. The connecting arms 232 of two adjacent sliding beams 23 within the same first sliding beam group M are connected, and the connection point is separated from the supporting foil 20. That is, the three sliding beams 23 within each group are interconnected in the middle, thereby forming two sliding arms 231 symmetrically arranged along the second direction Y between the two sliding beams 23. In this way, not only the number and density of the sliding arms 231 are increased, improving the load-bearing capacity of the entire supporting foil 20, but also the deformation forces between adjacent sliding beams 23 can be transmitted to each other, so that the deformations of the sliding beams 23 are balanced with each other, improving the deformation load-bearing capacity of each first sliding beam group M, and further improving the load-bearing capacity of the entire hydrodynamic gas bearing. It can be understood that in other embodiments of the present application, according to the actual design situation, the number and distribution of the above-mentioned first sliding beam groups M can be appropriately changed, and the number of sliding beams 23 within each first sliding beam group M can also be increased or decreased. For example, it can be two or more than four, and no unique limitation is made here.

[0062] Please refer to Figure 9 , the widths of the sliding beams 23 in the same first sliding beam group M are equal. And along the first direction X, the width of the first sliding beam group M gradually increases from both sides to the middle, so that the first sliding beam groups M in different axial directions have different sizes, thereby having different stiffness and damping properties, and further being able to better adapt to the actual load.

[0063] In addition, in this embodiment, the sliding beams 23 in the same row along the first direction X are aligned at both ends along the second direction Y, so that the deformation forces of the sliding beams 23 in each first sliding beam group M are transmitted smoothly.

[0064] Embodiment Four:

[0065] The essential technical features of the hydrodynamic gas bearing in this embodiment are basically the same as those of the hydrodynamic gas bearing in Embodiment One. The difference is that in this embodiment, please refer to Figures 10 to 12, multiple groups of second sliding beam groups N are distributed on the supporting foil 20, and the second sliding beam groups N are respectively distributed at intervals along the first direction X and the second direction Y. The second sliding beam group N includes at least two sliding beams 23, wherein at least two sliding beams 23 are respectively a first sliding beam 23a and at least one second sliding beam 23b; the first sliding beam 23a includes two first sliding arms 231a, and the second sliding beam 23b includes two second sliding arms 231b. Each second sliding arm 231b is correspondingly nested in the two first sliding arms 231a, that is, the first sliding arm 231a is a hollow arm and is arranged on the outside, and each second sliding arm 231b is a solid arm and is arranged inside the first sliding arm 231a. Thus, it can be seen that the length of the first sliding arm 231a in the second direction Y is greater than the length of the second sliding arm 231b in the second direction Y. Please refer to Figure 11 , after the supporting foil 20 is bent and installed, first, the first sliding end 2311a of the first sliding arm 231a contacts the inner wall of the bearing sleeve 10, while the second sliding end 2311b of the second sliding arm 231b is in a suspended state, that is, the first sliding arm 231a plays a supporting role, while the second sliding arm 231b does not play a supporting role. Please refer to Figure 12 , when the hydrodynamic gas bearing bears a certain load, the top foil 30 acts on the supporting foil 20, and the supporting foil 20 generates a certain deformation. The distance between the supporting foil 20 and the inner wall of the bearing sleeve 10 decreases, and the first sliding arm 231a will deform accordingly. When the first sliding arm 231a deforms to a certain extent, the second sliding end 2311b of the second sliding arm 231b then contacts the inner wall of the bearing sleeve 10 and begins to have a supporting effect. At this time, both the first sliding arm 231a and the second sliding arm 231b play a load-bearing role. To sum up, through the arrangement of the inner and outer nesting of the first sliding beam 23a and the second sliding beam 23b, the stiffness of the supporting foil 20 increases with the increase of the load, thereby improving the load-bearing capacity of the entire hydrodynamic gas bearing.

[0066] Specifically, in this embodiment, please refer to Figure 10 , the two second sliding arms 231b of the second sliding beam 23b are respectively formed on the two first sliding arms 231a of the first sliding beam 23a, that is, as Figure 10As shown, each second sliding beam 23b located above is formed on the first sliding arm 231a of the first sliding beam 23a located above, and each second sliding arm 231b located below the second sliding beam 23b is formed on the first sliding arm 231a located below the first sliding beam 23a. And the second sliding arms 231b located above have the same size and are aligned with each other, and the second sliding arms 231b located below have the same size and are aligned with each other. When there are two or more second sliding beams 23b formed in the first sliding beam 23a, the second sliding beams 23b are spaced apart along the first direction X.

[0067] In a specific embodiment, please refer to Figure 10 , along the first direction X, two adjacent first sliding beams 23a are staggered from each other along the second direction Y and at least partially cross each other, so that the density of the first sliding ends 2311a and the second sliding ends 2311b in the middle region is greater, increasing the Coulomb friction between the inner wall of the corresponding region of the bearing sleeve 10 and the first sliding ends 2311 and the second sliding ends 2311b, thereby improving the stability of the hydrodynamic gas bearing.

[0068] Embodiment Five:

[0069] The essential technical features of the hydrodynamic gas bearing in this embodiment are basically the same as those of the hydrodynamic gas bearing in Embodiment Four, and the difference lies in that: in this embodiment, please refer to Figure 13 , at least one second sliding beam 23b is distributed on each first sliding arm 231a of the first sliding beam 23a, and when the number of second sliding beams 23b is two or more, the second sliding beams 23b are spaced apart along the first direction X. By distributing at least one second sliding beam 23b on each first sliding arm 231a in this application, the support foil 20 can change various stiffnesses and damping properties when bearing different loads, and the load-bearing adaptability of the entire hydrodynamic gas bearing is better.

[0070] Embodiment Six:

[0071] The essential technical features of the hydrodynamic gas bearing in this embodiment are basically the same as those of the hydrodynamic gas bearing in Embodiment Four, and the difference lies in that: in this embodiment, please refer to Figure 14, in the same second sliding beam group N, the width ratio of the first sliding beam 23a to the second sliding beam 23b is a first ratio, and the first ratio gradually increases from both sides to the middle along the first direction X. That is, when the widths of all the first sliding beams 23a are equal, the widths of all the second sliding beams 23b gradually decrease from both sides to the middle along the first direction X. In this application, by varying the first ratio of the first sliding beam 23a to the second sliding beam 23b with the axial position of the support foil 20, the critical loads for the support foil 20 to change stiffness at different axial positions are different, enabling better utilization of different loads at different axial positions.

[0072] Embodiment Seven:

[0073] In this embodiment, the essential technical features of the hydrodynamic gas bearing are basically the same as those of the hydrodynamic gas bearing in Embodiment One, and the differences are as follows: Please refer to Figure 15 and Figure 16 , in the radial direction of the hydrodynamic gas bearing, the number of layers of the support foil 20 is at least one layer. When the number of layers of the support foil 20 is two or more, the support foils 20 are stacked in sequence from the inside to the outside. The sliding beams 23 on the support foil 20 located on the inner side sequentially pass through the support foils 20 located outside it and can be supported on the inner wall of the bearing sleeve 10 and slide on the inner wall of the bearing sleeve 10, and the lengths of the sliding beams 23 that are stacked on each other in the support foils 20 gradually decrease from the inside to the outside along the radial direction. Thus, please refer to Figure 15 , when the hydrodynamic gas bearing bears a certain load, the top foil 30 acts on each support foil 20, and each support foil 20 undergoes a certain deformation. The distance between the support foil 20 and the inner wall of the bearing sleeve 10 decreases. The sliding beam 23 on the support foil 20 closest to the top foil 30 begins to contact the inner wall of the bearing sleeve 10 and deform. When the sliding beam 23 deforms to a certain extent, the sliding beam 23 located outside it begins to contact the inner wall of the bearing sleeve 10 and deform, and so on, until the outermost sliding beam 23 contacts the inner wall of the bearing sleeve 10 and deforms. In summary, when the number of layers of the support foil 20 is more, the number of layers of the sliding beam 23 is more, and the overall stiffness of each support foil 20 increases with the increase of the load, thereby improving the load-bearing capacity of the entire hydrodynamic gas bearing.

[0074] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A hydrodynamic gas bearing, characterized in that, it includes a bearing sleeve, a top foil installed in the bearing sleeve and used to form a gas film gap with a rotor, and at least two circumferentially spaced support foil sheets supported between the bearing sleeve and the top foil; both ends of the top foil are respectively installed on the bearing sleeve; the support foil sheet has a flat sheet structure, one end of the support foil sheet in the circumferential direction after bending is installed on the bearing sleeve, and the other end is suspended; a plurality of sliding beams are formed by hollowing out the support foil sheet, the sliding beam has two sliding ends, and each sliding end can support on and slide on the inner wall of the bearing sleeve after the support foil sheet is bent; each sliding beam is distributed along a first direction and a second direction respectively, the first direction is set as the axial direction after the support foil sheet is installed, and the second direction is set as the circumferential direction after the support foil sheet is installed; the sliding beam includes a connecting arm and two sliding arms, the two sliding arms are symmetrically arranged on both sides of the connecting arm along the second direction, one end of the sliding arm is connected to the connecting arm, and the other end of the sliding arm is the sliding end; multiple groups of first sliding beam groups are distributed on the support foil sheet, and each first sliding beam group is spaced along the first direction and the second direction respectively; the first sliding beam group includes at least two sliding beams spaced along the first direction, the connecting arms of two adjacent sliding beams in the same first sliding beam group are connected, and the connection part is separated from the support foil sheet and forms two symmetrically arranged sliding arms; the widths of the sliding beams in the same group of first sliding beam groups are equal.

2. The hydrodynamic gas bearing according to claim 1, characterized in that, the width of the sliding arm in the first direction gradually increases from the sliding end to the connecting arm; wherein, the sliding arm is trapezoidal or arc-shaped.

3. The hydrodynamic gas bearing according to claim 1 or 2, characterized in that, along the radial direction of the hydrodynamic gas bearing, the number of layers of the support foil sheet is at least one layer; when the number of layers of the support foil sheet is two or more, each support foil sheet is stacked in sequence from inside to outside, the sliding beams on the support foil sheet located inside sequentially pass through the support foil sheets located outside it and can support on and slide on the inner wall of the bearing sleeve, and the lengths of the sliding beams laminated with each other in each support foil sheet decrease sequentially from inside to outside along the radial direction.

4. A hydrodynamic gas bearing, characterized in that, It includes a bearing sleeve, a top foil installed in the bearing sleeve and used to form an air film gap with the rotor, and at least two circumferentially spaced support foil pieces supported between the bearing sleeve and the top foil; both ends of the top foil are respectively installed on the bearing sleeve; the support foil pieces are in a flat sheet structure, one end of the support foil piece after bending is installed on the bearing sleeve along the circumferential direction, and the other end is suspended; a plurality of sliding beams are formed by hollowing out the support foil piece, the sliding beam has two sliding ends, and each of the sliding ends can be supported on the inner wall of the bearing sleeve and slide on the inner wall of the bearing sleeve after the support foil piece is bent; multiple groups of second sliding beam groups are distributed on the support foil piece, and each of the second sliding beam groups is spaced apart along a first direction and a second direction; the second sliding beam group includes at least two sliding beams, wherein at least two sliding beams are respectively a first sliding beam and at least one second sliding beam; the first sliding beam includes two first sliding arms, the second sliding beam includes two second sliding arms, and each of the second sliding arms is correspondingly nested in the two first sliding arms.

5. The hydrodynamic gas bearing according to claim 4, wherein, the two second sliding arms of the second sliding beam are respectively formed on the two first sliding arms of the first sliding beam; when two or more second sliding beams are formed in the first sliding beam, each of the second sliding beams is spaced apart along the first direction.

6. The hydrodynamic gas bearing according to claim 4, wherein, at least one second sliding beam is distributed on each first sliding arm of the first sliding beam, and when the number of second sliding beams is two or more, each of the second sliding beams is spaced apart along the first direction.

7. The hydrodynamic gas bearing according to any one of claims 4 to 6, wherein, the first sliding beam in the same group of the second sliding beam group and the second sliding beam have a first ratio, and the first ratio gradually increases from both sides to the middle along the first direction.

8. The hydrodynamic gas bearing according to any one of claims 4 to 6, wherein, the adjacent two first sliding beams in the first direction are staggered from each other along the second direction and at least partially cross each other.

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