Thrust Air Foil Bearings

Abstract

The present invention provides a thrust air foil bearing, which relates to the technical field of turbomachinery, and solves the technical problem that the manufacturing and installation precision requirements of air foil bearings in the prior art are relatively high. The device includes a top foil, a first foil layer, a second foil layer, a third foil layer and a fourth foil layer, which are stacked and arranged in sequence and connected together by pins; the top foil includes a multi-petal top foil and a bottom foil of a circular ring structure, the top foil is welded to the bottom foil, and all the top foils are evenly distributed around the inner circle of the bottom foil; the bottom foil includes a plane annular area and a steep annular area, and a plurality of slope surfaces are arranged on the steep annular area, each slope surface corresponds to a top foil, the welding area is welded to the lower end of the slope surface, and the top foil plane area is located at the upper end of the slope surface. The present invention is used to facilitate manufacturing and installation.

Description

Technical Field

[0001] The invention relates to the technical field of turbomachinery, and in particular to a thrust air foil bearing. Background Art

[0002] Air foil bearing is a kind of gas dynamic pressure bearing. It is widely used in turbomachinery such as air cycle machine, air compressor, micro gas turbine, etc. due to its high temperature resistance, high speed, oil-free lubrication, low friction loss, etc. Air dynamic pressure foil bearing uses the wedge effect. As the speed of the rotor increases, the gas with a certain viscosity in the surrounding environment is dragged into the wedge-shaped air cavity formed by the rotor and the bearing support surface by the high-speed rotating rotor. When the speed of the rotor rises to a certain level, the gas pressure in the wedge-shaped air cavity increases and supports the rotor.

[0003] At present, the most common and widely used is the corrugated foil type air foil bearing, which has good stiffness and damping characteristics. Usually, the corrugated foil type air foil bearing includes three layers: flat foil top foil, corrugated foil corrugated foil and supporting bottom plate. The bearing includes multiple corrugated foils and top foils. Each corrugated foil is fixed to the bottom plate by welding, and each top foil is fixed to the corrugated foil or the bottom plate by welding, forming a structure in which the bottom plate supports the corrugated foil and the corrugated foil supports the top foil. When working, the top foil plane area contacts the rotor in the static state, and there is a wedge-shaped area formed by the supporting structure between the front and rear lobes. After the rotor rotates, the top foil needs to overcome the starting friction torque, and the rotor drags the gas with a certain viscosity in the surrounding environment into the wedge for compression. When the speed increases to a certain level, the rotor is suspended.

[0004] The applicant has found that the prior art has at least the following technical problems:

[0005] In the prior art, the unique wave structure of the air foil bearing leads to relatively high requirements for the manufacturing and installation precision of the air foil bearing, making it difficult to control the manufacturing consistency of each petal, which limits its large-scale mass production application. Summary of the invention

[0006] The purpose of the present invention is to provide a thrust air foil bearing to solve the technical problem that the manufacturing and installation precision requirements of air foil bearings in the prior art are relatively high. The preferred technical solutions among the many technical solutions provided by the present invention can produce many technical effects as described below.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A thrust air foil bearing provided by the present invention comprises a top foil, a first foil layer, a second foil layer, a third foil layer and a fourth foil layer, wherein the top foil, the first foil layer, the second foil layer, the third foil layer and the fourth foil layer are sequentially stacked and arranged and connected together by pins;

[0009] The top foil comprises a multi-petal top foil and a bottom foil of an annular structure, the top foil is welded to the bottom foil, and all the top foils are evenly distributed around the inner circle of the bottom foil;

[0010] The top foil sheet comprises a top foil sheet plane area, a wedge-shaped area and a welding area, the lower end surface of the wedge-shaped area is connected to the welding area, the upper end surface of the wedge-shaped area is connected to the top foil sheet plane area, and the welding area is welded to the bottom foil sheet;

[0011] The bottom plate foil includes a flat annular area and a steep annular area, the inner circle of the flat annular area is connected to the outer circle of the steep annular area, a plurality of slope surfaces are arranged on the steep annular area, each of the slope surfaces corresponds to one of the top foil pieces, the welding area is welded to the lower end of the slope surface, and the flat area of ​​the top foil piece is located at the upper end of the slope surface.

[0012] Optionally, the top foil is a stamped part.

[0013] Optionally, the first layer of foil includes a first layer of bottom plate and a first layer of cantilever plate group in a circular ring structure, one end of the first layer of cantilever plate group is fixedly connected to the inner circle of the first layer of bottom plate, the free end of the first layer of cantilever plate group points to the center of the first layer of bottom plate, there are multiple first layer of cantilever plate groups, all of which are distributed along the circumferential direction of the first layer of bottom plate, and the first layer of cantilever plate group supports the top foil.

[0014] Optionally, the first layer of cantilever sheet group includes a narrow cantilever sheet and a wide cantilever sheet, a gap is arranged between the narrow cantilever sheet and the wide cantilever sheet, one end of the narrow cantilever sheet and the wide cantilever sheet are both fixedly connected to the inner circle of the first layer of bottom plate sheet, and the free ends of the narrow cantilever sheet and the wide cantilever sheet point to the center of the circle of the first layer of bottom plate sheet.

[0015] Optionally, the second layer of foil includes a second layer of bottom plate and a second layer of cantilever plate group in a circular ring structure, one end of the second layer of cantilever plate group is fixedly connected to the inner circle of the second layer of bottom plate, the free end of the second layer of cantilever plate group points to the center of the second layer of bottom plate, there are multiple second layer of cantilever plate groups, all of the second layer of cantilever plate groups are distributed along the circumferential direction of the second layer of bottom plate, and the second layer of cantilever plate group supports the first layer of foil.

[0016] Optionally, the second layer cantilever sheet group includes two second layer cantilever sheets with rod-shaped structures, a gap is arranged between the two second layer cantilever sheets, one end of the two second layer cantilever sheets are fixedly connected to the inner circle of the second layer bottom plate sheet, and the free ends of the two second layer cantilever sheets point to the center of the second layer bottom plate sheet.

[0017] Optionally, the third layer of foil includes a third layer of bottom plate and a third layer of cantilever plate in a circular ring structure, one end of the third layer of cantilever plate is fixedly connected to the inner circle of the third layer of bottom plate, the free end of the third layer of cantilever plate points to the center of the third layer of bottom plate, there are multiple third layer of cantilever plates, all of which are distributed along the circumferential direction of the third layer of bottom plate, and the third layer of cantilever plates support the second layer of foil.

[0018] Optionally, the third layer of cantilever piece is a fan-shaped structure, and a free end of the third layer of cantilever piece is provided with an annular opening groove.

[0019] Optionally, the fourth layer of foil includes a fourth layer of bottom plate with a circular ring structure and a fourth layer of cantilever plate with a rod-shaped structure, one end of the fourth layer of cantilever plate is fixedly connected to the inner circle of the fourth layer of bottom plate, the free end of the fourth layer of cantilever plate points to the center of the fourth layer of bottom plate, there are multiple fourth layer of cantilever plates, all of which are distributed along the circumferential direction of the fourth layer of bottom plate, and the fourth layer of cantilever plates support the third layer of foil.

[0020] Optionally, the top foil, the first foil layer, the second foil layer, the third foil layer and the fourth foil layer are all provided with fixing pin holes;

[0021] An annular groove is provided at the connection between the planar annular area and the steep annular area;

[0022] The outer diameters of the top foil, the first foil layer, the second foil layer, the third foil layer and the fourth foil layer are equal, and the inner diameter of the fourth foil layer is greater than the inner diameters of the first foil layer, the second foil layer and the third foil layer.

[0023] The thrust air foil bearing provided by the present invention uses pins to connect each foil, so that installation is relatively simple. At the same time, compared with the wave structure of the air foil bearing in the prior art, the top foil and the bottom foil have a simpler structure, are convenient to process, have relatively low precision requirements, have good manufacturing consistency, are easy to mass produce, and significantly reduce the manufacturing cost, so as to solve the technical problem of relatively high manufacturing and installation precision requirements of the air foil bearing in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 is an exploded view of a thrust air foil bearing provided by an embodiment of the present invention;

[0026] Figure 2 is a schematic structural diagram of a top foil of a thrust air foil bearing provided by an embodiment of the present invention;

[0027] Figure 3 It is a partial structural schematic diagram of the circumferential development of the top foil of the thrust air foil bearing provided by an embodiment of the present invention;

[0028] Figure 4 It is a schematic diagram of a partial structure of a circumferentially unfolded thrust air foil bearing provided by an embodiment of the present invention;

[0029] Figure 5 is a schematic structural diagram of a first layer of foil of a thrust air foil bearing provided by an embodiment of the present invention;

[0030] Figure 6 is a schematic structural diagram of a second foil layer of a thrust air foil bearing provided by an embodiment of the present invention;

[0031] Figure 7 is a schematic structural diagram of the third foil layer of the thrust air foil bearing provided by an embodiment of the present invention;

[0032] Figure 8 is a schematic structural diagram of the fourth foil layer of the thrust air foil bearing provided by an embodiment of the present invention;

[0033] In the figure, 1, top foil; 11, top foil; 111, top foil plane area; 112, wedge area; 113, welding area; 12, bottom plate foil; 121, flat annular area; 122, steep annular area; 1221, slope surface; 123, annular groove; 2, first layer of foil; 21, first layer of bottom plate; 22, first layer of cantilever plate group; 221, narrow cantilever plate; 222, wide cantilever plate; 23, first connecting plate; 3, second layer of foil; 31, second layer of bottom plate; 32, second layer of cantilever plate group; 321, second layer of cantilever plate; 4, third layer of foil; 41, third layer of bottom plate; 42, third layer of cantilever plate; 421, annular opening groove; 43, second connecting piece; 5, fourth layer of foil; 51, fourth layer of bottom plate; 52, fourth layer of cantilever plate; 6, fixing pin hole. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0035] The present invention provides a thrust air foil bearing, comprising a top foil 1, a first foil layer 2, a second foil layer 3, a third foil layer 4 and a fourth foil layer 5, wherein Figure 1 , a top foil 1, a first foil 2, a second foil 3, a third foil 4 and a fourth foil 5 are sequentially stacked and connected together by pins;

[0036] The top foil 1 comprises a multi-petal top foil sheet 11 and a bottom foil sheet 12 of an annular structure, see Figure 2 , the top foil 11 is welded to the bottom foil 12, and all the top foils 11 are evenly distributed around the inner circle of the bottom foil 12;

[0037] The top foil 11 includes a top foil plane area 111, a wedge-shaped area 112 and a welding area 113, see Figure 3 , the lower end surface of the wedge-shaped area 112 is connected to the welding area 113, the upper end surface of the wedge-shaped area 112 is connected to the top foil plane area 111, and the welding area 113 is welded to the bottom foil 12;

[0038] The bottom plate foil 12 includes a plane annular area 121 and a steep surface annular area 122. The inner circle of the plane annular area 121 is connected to the outer circle of the steep surface annular area 122. A plurality of slope surfaces 1221 are arranged on the steep surface annular area 122. Each slope surface 1221 corresponds to a top foil 11. The slope of the slope surface 1221 is relatively small. The welding area 113 is welded to the lower end of the slope surface 1221. The top foil plane area 111 is located at the upper end of the slope surface 1221. The top foil plane area 111 is not connected to the slope surface 1221 in order to increase the elasticity of the top foil 11. A wedge is formed between the top foil 11 and the slope surface 1221. A thrust air foil bearing provided by the present invention uses pins to connect each foil, so that installation is relatively simple. At the same time, compared with the wave structure of the air foil bearing in the prior art, the top foil 11 and the bottom foil 12 have a simpler structure, are convenient to process, have relatively low precision requirements, have good manufacturing consistency, are easy to mass produce, and significantly reduce the manufacturing cost, so as to solve the technical problem of relatively high manufacturing and installation precision requirements of the air foil bearing in the prior art.

[0039] As an optional implementation, the top foil 11 may be a stamped part, so that the top foil 11 is easy to process.

[0040] As an optional embodiment, the first foil sheet 2 includes a first bottom plate sheet 21 and a first cantilever sheet group 22 in an annular structure, see Figure 5 One end of the first layer cantilever sheet group 22 is fixedly connected to the inner circle of the first layer bottom plate sheet 21, and the free end of the first layer cantilever sheet group 22 points to the center of the first layer bottom plate sheet 21. There are multiple first layer cantilever sheet groups 22, and the number of the first layer cantilever sheet groups 22 is the same as the number of the top foil sheet 11. All the first layer cantilever sheet groups 22 are distributed along the circumferential direction of the first layer bottom plate sheet 21. The first layer cantilever sheet group 22 supports the top foil 1. The first layer cantilever sheet group 22 and the top foil sheet 11 are respectively located on both sides of the bottom plate foil sheet 12, and one first layer cantilever sheet group 22 supports a slope surface 1221.

[0041] As an optional embodiment, the first layer cantilever sheet group 22 includes a narrow cantilever sheet 221 and a wide cantilever sheet 222, and a gap is set between the narrow cantilever sheet 221 and the wide cantilever sheet 222. One end of the narrow cantilever sheet 221 and the wide cantilever sheet 222 are fixedly connected to the inner circle of the first layer bottom plate sheet 21, and one end of the narrow cantilever sheet 221 and the wide cantilever sheet 222 are fixedly connected to the inner circle of the first layer bottom plate sheet 21 through the first connecting sheet 23. The length of a connecting piece 23 is relatively small, so that there is a gap between the ends of the narrow cantilever piece 221 and the wide cantilever piece 222 and the inner circle of the first layer of bottom plate 21. The narrow cantilever piece 221 and the wide cantilever piece 222 are distributed at intervals on the first layer of bottom plate 21. The free ends of the narrow cantilever piece 221 and the wide cantilever piece 222 point to the center of the first layer of bottom plate 21. A narrow cantilever piece 221 and a wide cantilever piece 222 each support a slope surface 1221.

[0042] As an optional embodiment, the second foil sheet 3 includes a second bottom plate sheet 31 of annular structure and a second cantilever sheet group 32, see Figure 6 One end of the second layer cantilever sheet group 32 is fixedly connected to the inner circle of the second layer bottom plate 31, and the free end of the second layer cantilever sheet group 32 points to the center of the second layer bottom plate 31. There are multiple second layer cantilever sheet groups 32, and the number of the second layer cantilever sheet groups 32 is the same as the number of the first layer cantilever sheet groups 22. All the second layer cantilever sheet groups 32 are distributed along the circumferential direction of the second layer bottom plate 31. The second layer cantilever sheet group 32 supports the first layer foil 2, and one second layer cantilever sheet group 32 supports one first layer cantilever sheet group 22.

[0043] As an optional implementation, the second layer cantilever sheet group 32 includes two rod-shaped second layer cantilever sheets 321, a gap is arranged between the two second layer cantilever sheets 321, one end of the two second layer cantilever sheets 321 are fixedly connected to the inner circle of the second layer bottom plate sheet 31, the free ends of the two second layer cantilever sheets 321 point to the center of the second layer bottom plate sheet 31, and the two second layer cantilever sheets 321 in a second layer cantilever sheet group 32 respectively support a narrow cantilever sheet 221 and a wide cantilever sheet 222.

[0044] As an optional embodiment, the third foil sheet 4 includes a third bottom plate sheet 41 and a third cantilever sheet 42 in an annular structure, see Figure 7One end of the third layer cantilever piece 42 is fixedly connected to the inner circle of the third layer bottom plate piece 41, and one end of the third layer cantilever piece 42 is fixedly connected to the inner circle of the third layer bottom plate piece 41 through the second connecting piece 43. The length of the second connecting piece 43 is relatively small, so that there is a gap between one end of the third layer cantilever piece 42 and the inner circle of the third layer bottom plate piece 41, and the free end of the third layer cantilever piece 42 points to the center of the third layer bottom plate piece 41. There are multiple third layer cantilever pieces 42, and the number of the third layer cantilever pieces 42 is the same as the number of the second layer cantilever piece group 32. All third layer cantilever pieces 42 are distributed along the circumferential direction of the third layer bottom plate piece 41. The third layer cantilever piece 42 supports the second layer foil 3, and one third layer cantilever piece 42 supports two second layer cantilever pieces 321 and the two second layer cantilever pieces 321 are located on both sides of the third layer cantilever piece 42.

[0045] As an optional implementation, the third layer cantilever sheet 42 is a fan-shaped structure, and the side with a longer arc length on the third layer cantilever sheet 42 is fixedly connected to the inner circle of the third layer bottom plate sheet 41, and the free end of the third layer cantilever sheet 42 is provided with an annular opening groove 421, and the annular opening groove 421 is intended to reduce the stiffness of the third layer foil 4.

[0046] As an optional embodiment, the fourth foil sheet 5 includes a fourth bottom plate sheet 51 of an annular structure and a fourth cantilever sheet 52 of a rod-shaped structure, see Figure 8 One end of the fourth-layer cantilever sheet 52 is fixedly connected to the inner circle of the fourth-layer bottom plate sheet 51, and the free end of the fourth-layer cantilever sheet 52 points to the center of the fourth-layer bottom plate sheet 51. There are multiple fourth-layer cantilever sheets 52, and the number of the fourth-layer cantilever sheets 52 is the same as the number of the third-layer cantilever sheets 42. All fourth-layer cantilever sheets 52 are distributed along the circumferential direction of the fourth-layer bottom plate sheet 51. The fourth-layer cantilever sheet 52 supports the third-layer foil 4, and one fourth-layer cantilever sheet 52 supports one third-layer cantilever sheet 42.

[0047] As an optional embodiment, the top foil 1, the first foil 2, the second foil 3, the third foil 4 and the fourth foil 5 are all provided with fixing pin holes 6, and the number of fixing pin holes 6 on each foil is the same and the positions are corresponding, so that the pin can be easily passed through the fixing pin holes 6 of each foil;

[0048] An annular groove 123 is provided at the connection between the flat annular region 121 and the steep annular region 122. The annular groove 123 is for facilitating the deformation of the top foil 1 and reducing the rigidity of the top foil 1.

[0049] The outer diameters of the top foil 1, the first foil layer 2, the second foil layer 3, the third foil layer 4 and the fourth foil layer 5 are equal, the inner diameter of the fourth foil layer 5 is larger than the inner diameters of the first foil layer 2, the second foil layer 3 and the third foil layer 4, the inner diameter of the fourth foil layer 5 refers to the diameter of the circle formed by the free end of the fourth cantilever sheet 52 around the center of the fourth bottom plate sheet 51, it can also be said that the length of the fourth cantilever sheet 52 is smaller than the lengths of the first cantilever sheet group 22, the second cantilever sheet group 32 and the third cantilever sheet 42.

[0050] In the present application, a fourth-layer cantilever sheet 52 supports a third-layer cantilever sheet 42, a third-layer cantilever sheet 42 supports two second-layer cantilever sheets 321 and the two second-layer cantilever sheets 321 are located on both sides of the third-layer cantilever sheet 42, the two second-layer cantilever sheets 321 respectively support a narrow cantilever sheet 221 and a wide cantilever sheet 222, a narrow cantilever sheet 221 and a wide cantilever sheet 222 both support a slope surface 1221, and through mutual cross-distribution, the damping characteristics of the thrust air foil bearing are increased, and the impact resistance of the thrust air foil bearing is improved.

[0051] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A thrust air foil bearing, characterized in that: It comprises a top foil (1), a first foil layer (2), a second foil layer (3), a third foil layer (4) and a fourth foil layer (5), wherein: The top foil (1), the first foil layer (2), the second foil layer (3), the third foil layer (4) and the fourth foil layer (5) are stacked in sequence and connected together by pins; The top foil (1) comprises a multi-petal top foil sheet (11) and a bottom foil sheet (12) of an annular structure, the top foil sheet (11) and the bottom foil sheet (12) are welded and connected, and all the top foil sheets (11) are evenly distributed around the inner circle of the bottom foil sheet (12); The top foil sheet (11) comprises a top foil sheet plane area (111), a wedge-shaped area (112) and a welding area (113); the lower end surface of the wedge-shaped area (112) is connected to the welding area (113); the upper end surface of the wedge-shaped area (112) is connected to the top foil sheet plane area (111); and the welding area (113) is welded to the bottom foil sheet (12); The bottom plate foil (12) comprises a planar annular region (121) and a steep annular region (122); the inner circle of the planar annular region (121) is connected to the outer circle of the steep annular region (122); a plurality of slope surfaces (1221) are arranged on the steep annular region (122); each slope surface (1221) corresponds to one of the top foils (11); the welding region (113) is welded to the lower end of the slope surface (1221); and the top foil planar region (111) is located at the upper end of the slope surface (1221).

2. The thrust air foil bearing according to claim 1, characterized in that: The top foil sheet (11) is a stamped part.

3. The thrust air foil bearing according to claim 1, characterized in that: The first layer of foil (2) comprises a first layer of bottom plate (21) and a first layer of cantilever plate group (22) in a circular ring structure, one end of the first layer of cantilever plate group (22) is fixedly connected to the inner circle of the first layer of bottom plate (21), the free end of the first layer of cantilever plate group (22) points to the center of the circle of the first layer of bottom plate (21), there are a plurality of first layer of cantilever plate groups (22), all of the first layer of cantilever plate groups (22) are distributed along the circumferential direction of the first layer of bottom plate (21), and the first layer of cantilever plate group (22) supports the top foil (1).

4. The thrust air foil bearing according to claim 3, characterized in that: The first layer of cantilever sheet group (22) comprises a narrow cantilever sheet (221) and a wide cantilever sheet (222), a gap is provided between the narrow cantilever sheet (221) and the wide cantilever sheet (222), one end of the narrow cantilever sheet (221) and the wide cantilever sheet (222) are both fixedly connected to the inner circle of the first layer of bottom plate sheet (21), and the free ends of the narrow cantilever sheet (221) and the wide cantilever sheet (222) point to the center of the circle of the first layer of bottom plate sheet (21).

5. The thrust air foil bearing according to claim 1, characterized in that: The second layer of foil (3) comprises a second layer of bottom plate (31) and a second layer of cantilever plate group (32) in a circular ring structure, one end of the second layer of cantilever plate group (32) is fixedly connected to the inner circle of the second layer of bottom plate (31), the free end of the second layer of cantilever plate group (32) points to the center of the second layer of bottom plate (31), there are multiple second layer of cantilever plate groups (32), all of the second layer of cantilever plate groups (32) are distributed along the circumferential direction of the second layer of bottom plate (31), and the second layer of cantilever plate group (32) supports the first layer of foil (2).

6. The thrust air foil bearing according to claim 5, characterized in that: The second-layer cantilever sheet group (32) comprises two second-layer cantilever sheets (321) of rod-shaped structure, a gap is provided between the two second-layer cantilever sheets (321), one end of the two second-layer cantilever sheets (321) are fixedly connected to the inner circle of the second-layer bottom plate sheet (31), and the free ends of the two second-layer cantilever sheets (321) point to the center of the second-layer bottom plate sheet (31).

7. The thrust air foil bearing according to claim 1, characterized in that: The third layer of foil (4) comprises a third layer of bottom plate (41) and a third layer of cantilever plate (42) in a circular ring structure, one end of the third layer of cantilever plate (42) is fixedly connected to the inner circle of the third layer of bottom plate (41), the free end of the third layer of cantilever plate (42) points to the center of the third layer of bottom plate (41), there are multiple third layer of cantilever plates (42), all of the third layer of cantilever plates (42) are distributed along the circumferential direction of the third layer of bottom plate (41), and the third layer of cantilever plates (42) support the second layer of foil (3).

8. The thrust air foil bearing according to claim 7, characterized in that: The third layer cantilever piece (42) is a fan-shaped structure, and a free end of the third layer cantilever piece (42) is provided with an annular opening groove (421).

9. The thrust air foil bearing according to claim 1, characterized in that: The fourth layer of foil (5) comprises a fourth layer of bottom plate (51) with a circular ring structure and a fourth layer of cantilever plate (52) with a rod-shaped structure. One end of the fourth layer of cantilever plate (52) is fixedly connected to the inner circle of the fourth layer of bottom plate (51). The free end of the fourth layer of cantilever plate (52) points to the center of the fourth layer of bottom plate (51). There are multiple fourth layer of cantilever plates (52). All the fourth layer of cantilever plates (52) are distributed along the circumferential direction of the fourth layer of bottom plate (51). The fourth layer of cantilever plates (52) support the third layer of foil (4).

10. The thrust air foil bearing according to claim 1, characterized in that: The top foil (1), the first foil layer (2), the second foil layer (3), the third foil layer (4) and the fourth foil layer (5) are all provided with fixing pin holes (6); An annular groove (123) is provided at the connection between the planar annular region (121) and the steep annular region (122); The outer diameters of the top foil (1), the first foil layer (2), the second foil layer (3), the third foil layer (4) and the fourth foil layer (5) are equal, and the inner diameter of the fourth foil layer (5) is greater than the inner diameters of the first foil layer (2), the second foil layer (3) and the third foil layer (4).

Images