Gas dynamic pressure radial bearing, compressor and engine

Abstract

The application provides a gas dynamic pressure radial bearing, a compressor and an engine. The gas dynamic pressure radial bearing comprises a bearing seat (1), a second layer of wave foils (4), a first layer of wave foils (3) and a flat foil, the second layer of wave foils (4) and the first layer of wave foils (3) are stacked and arranged between the bearing seat (1) and the flat foil, the wave crests of the second layer of wave foils (4) and the first layer of wave foils (3) are arranged correspondingly, and there is a preset gap (203) between the wave crests of the second layer of wave foils (4) and the first layer of wave foils (3). According to the gas dynamic pressure radial bearing, the damping of the bearing can be increased, the overall rigidity of the bearing can be improved, and the load bearing performance of the bearing can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bearings, in particular to a gas dynamic pressure radial bearing, a compressor and an engine. BACKGROUND

[0002] The gas dynamic pressure radial bearing is an elastic supporting dynamic pressure gas bearing. The rotation of the rotating shaft drives the gas flow between the bearing and the rotating shaft. The viscous gas enters the wedge-shaped area to generate a fluid dynamic pressure effect, forming a high-pressure gas film. When the pressure of the dynamic pressure gas film is large enough, the rotating shaft can be suspended at high speed. When the rotating shaft rotates at high speed, the high-pressure gas film extrudes the bearing, and the top foil and the supporting wave foil are elastically deformed, increasing the gas film gap and ensuring the stable operation of the bearing.

[0003] A gas dynamic pressure radial bearing is disclosed in the prior art. The radial bearing is composed of a single layer of arch foil + a single layer of flat foil. The arch foil has a three-section structure, with high arch foils on both sides and a low arch foil in the middle. When the load is small, the high arch foils on both sides provide the bearing capacity, and when the load is large, the three-section arch foils together provide the bearing capacity. This design effectively adjusts the stiffness of the bearing. However, the segmentation reduces the contact area of the flat foil at low load, only 2 / 3 of the contact area, resulting in a decrease in the overall load-carrying performance of the radial bearing. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to provide a gas dynamic pressure radial bearing, a compressor and an engine, which can increase the damping of the bearing, improve the overall stiffness of the bearing and improve the load-carrying performance of the bearing.

[0005] To solve the above problems, the present application provides a gas dynamic pressure radial bearing, comprising a bearing seat, a second layer of wave foil, a first layer of wave foil and a flat foil. The second layer of wave foil and the first layer of wave foil are stacked and arranged between the bearing seat and the flat foil. The wave crests of the second layer of wave foil and the first layer of wave foil are correspondingly arranged, and there is a predetermined gap between the wave crests of the second layer of wave foil and the first layer of wave foil.

[0006] Preferably, the second layer of wave foil is arranged on the side close to the flat foil, the first layer of wave foil is arranged on the side close to the bearing seat, and the stiffness of the second layer of wave foil is smaller than the stiffness of the first layer of wave foil.

[0007] Preferably, the second layer of wave foil and the first layer of wave foil each comprise a flat section and an arc section. The flat section of the second layer of wave foil is supported on the flat section of the first layer of wave foil. The width of the flat section of the second layer of wave foil in the circumferential direction is smaller than the width of the flat section of the first layer of wave foil in the circumferential direction. The chord length of the arc section of the second layer of wave foil is greater than the chord length of the arc section of the first layer of wave foil.

[0008] Preferably, the flat foils are used to contact the rotating shaft, and along a radial direction from outside to inside, the flat foils comprise a first layer of flat foils, a second layer of flat foils and a third layer of flat foils which are sequentially attached, the circumferential extension direction of the first layer of flat foils and the second layer of flat foils is opposite to the rotating direction of the rotating shaft, and the circumferential extension direction of the second layer of flat foils is the same as the rotating direction of the rotating shaft.

[0009] Preferably, the first layer of flat foils, the second layer of flat foils and the third layer of flat foils are all in a whole-circumferential ring structure.

[0010] Preferably, the circumferential extension length of the second layer of flat foils is 3 / 5-4 / 5 of the whole circumference.

[0011] Preferably, the circumferential extension length of the second layer of flat foils is 2 / 3 of the whole circumference.

[0012] Preferably, the circumferential end of the second layer of flat foils is a slope structure, and the inclined surface of the slope structure faces the third layer of flat foils.

[0013] Preferably, the second layer of flat foils and the first layer of flat foils each comprise at least three flat foil segments which are sequentially arranged along the axial direction, wherein the flat segments and the arc-shaped segments of the flat foil segments at the two axial ends are correspondingly arranged along the circumferential direction, and the wave crests of the flat foil segment in the middle are staggered along the circumferential direction with the wave crests of the flat foil segments at the two axial ends.

[0014] Preferably, the flat foil segment comprises a first flat foil segment, a second flat foil segment, a third flat foil segment and a fourth flat foil segment, wherein the first flat foil segment and the fourth flat foil segment are located at the two axial ends of the bearing seat, the second flat foil segment and the third flat foil segment are located between the first flat foil segment and the fourth flat foil segment, the flat segments and the arc-shaped segments of the first flat foil segment and the fourth flat foil segment are correspondingly arranged along the circumferential direction, the flat segments and the arc-shaped segments of the second flat foil segment and the third flat foil segment are correspondingly arranged along the circumferential direction, and the wave crests of the first flat foil segment and the second flat foil segment are staggered along the circumferential direction.

[0015] Preferably, the first flat foil segment, the second flat foil segment, the third flat foil segment and the fourth flat foil segment are sequentially and spacedly arranged along the axial direction, the first flat foil segment, the second flat foil segment, the third flat foil segment and the fourth flat foil segment comprise fixed ends and free ends, the fixed ends of the first flat foil segment, the second flat foil segment, the third flat foil segment and the fourth flat foil segment are connected to the bearing seat, the circumferential length of the first flat foil segment and the fourth flat foil segment is greater than the circumferential length of the second flat foil segment and the third flat foil segment, the free ends of the first flat foil segment and the fourth flat foil segment are fixedly connected by a connecting rod, and the free ends of the second flat foil segment and the third flat foil segment are fixedly connected by a connecting rod.

[0016] Preferably, the inner surface of the flat foil is sprayed with a high-temperature-resistant lubricating coating.

[0017] According to another aspect of the present application, a compressor is provided, comprising a gas dynamic pressure radial bearing which is the above-mentioned gas dynamic pressure radial bearing.

[0018] According to another aspect of the present application, an engine is provided, comprising the gas dynamic pressure radial bearing or the compressor as described above.

[0019] The gas dynamic pressure radial bearing provided by the present application comprises a bearing seat, a second layer of wave foils, a first layer of wave foils and flat foils, the second layer of wave foils and the first layer of wave foils are stacked and arranged between the bearing seat and the flat foils, the wave crests of the second layer of wave foils and the first layer of wave foils are arranged correspondingly, and there is a preset gap between the wave crests of the second layer of wave foils and the first layer of wave foils. The gas dynamic pressure radial bearing adopts a stacked structure to form double-layer wave foils, and the double-layer wave foils are attached together as flat sections of wave valleys, and there is a preset gap between the arc-shaped sections as wave crests, so that the top layer of wave foils in contact with the flat foils provides the bearing capacity at low load, and since the entire top layer of wave foils can be in contact with the flat foils, the contact area of the wave foils and the flat foils is ensured, and the bearing capacity of a single wave foil is ensured, and after the top layer of wave foils is deformed to a certain extent and is in contact with the bottom layer of wave foils as the load increases, the two layers of wave foils jointly provide the bearing capacity, thereby further improving the bearing capacity of the gas dynamic pressure bearing and the stability of the bearing system. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Structure schematic diagram of the gas dynamic pressure radial bearing according to an embodiment of the present application;

[0021] Figure 2 Structure schematic diagram of the bearing structure of the gas dynamic pressure radial bearing according to an embodiment of the present application;

[0022] Figure 3 Structure schematic diagram of the first layer of wave foils of the gas dynamic pressure radial bearing according to an embodiment of the present application; Figure 2 Structure schematic diagram of the enlarged structure at I of the gas dynamic pressure radial bearing according to an embodiment of the present application;

[0023] Figure 4 Structure schematic diagram of the first layer of wave foils of the gas dynamic pressure radial bearing according to an embodiment of the present application;

[0024] Figure 5 Structure schematic diagram of the wave foils of the gas dynamic pressure radial bearing according to an embodiment of the present application.

[0025] The reference signs are as follows:

[0026] 1, bearing seat; 2, locking pin; 3, first layer of wave foils; 4, second layer of wave foils; 5, first layer of flat foils; 6, second layer of flat foils; 7, third layer of flat foils; 8, rotating shaft; 101, first wave foil section; 102, second wave foil section; 103, third wave foil section; 104, fourth wave foil section; 201, gas film; 202, wedge-shaped area; 203, gap. DETAILED DESCRIPTION

[0027] For reference Figures 1 to 5As shown, according to the embodiment of the present application, the gas dynamic pressure radial bearing comprises a bearing seat 1, a second layer of wave foil 4, a first layer of wave foil 3 and a flat foil, the second layer of wave foil 4 and the first layer of wave foil 3 are stacked and arranged between the bearing seat 1 and the flat foil, the wave crests of the second layer of wave foil 4 and the first layer of wave foil 3 are arranged correspondingly, and there is a preset gap 203 between the wave crests of the second layer of wave foil 4 and the first layer of wave foil 3.

[0028] The gas dynamic pressure radial bearing adopts a stacked structure to form double-layer wave foils, and the flat sections as wave troughs of the double-layer wave foils are attached together to form a common support, and there is a preset gap 203 between the arc-shaped sections as wave crests, so that at low load, the top layer of wave foil in contact with the flat foil among the first layer of wave foil 3 and the second layer of wave foil 4 provides the bearing capacity, since the entire top layer of wave foil can be in contact with the flat foil, the contact area of the wave foil and the flat foil is ensured, and the bearing capacity of a single wave foil is ensured, and as the load increases, the top layer of wave foil is deformed to contact the bottom layer of wave foil, and the two layers of wave foils jointly provide the bearing capacity, thereby further improving the bearing capacity of the gas dynamic pressure bearing and the stability of the bearing system. In the embodiment, the wave foil close to the flat foil is the top layer of wave foil, and the wave foil away from the flat foil is the bottom layer of wave foil.

[0029] In one embodiment, the second layer of wave foil 4 is arranged on the side close to the flat foil, the first layer of wave foil 3 is arranged on the side close to the bearing seat 1, and the rigidity of the second layer of wave foil 4 is less than that of the first layer of wave foil 3. In the embodiment, since there is a height difference between the two layers of wave foils, the gap 203 is provided at the wave crest position, and the rigidity of the top layer of wave foil is less than that of the bottom layer of wave foil, so that the top layer of wave foil can be used to provide low-load bearing capacity, and when the load is large, the double-layer wave foils can be used to provide bearing capacity. At the same time, since the rigidity of the bottom layer of wave foil is greater, it can bear a larger load, and can provide a better support to the top layer of wave foil, and the different rigidity of the two layers of wave foils can provide better bearing performance, thereby further improving the stability of the bearing system.

[0030] In one embodiment, the height of the gap 203 is 20% to 35% of the wave crest height of the second layer of wave foil 4, and as a preferred embodiment, the height of the gap 203 is 27% of the wave crest height of the second layer of wave foil 4.

[0031] In one embodiment, the second layer of wave foil 4 and the first layer of wave foil 3 each comprise a flat section and an arc-shaped section, the flat section of the second layer of wave foil 4 is supported on the flat section of the first layer of wave foil 3, the width of the flat section of the second layer of wave foil 4 in the circumferential direction is less than the width of the flat section of the first layer of wave foil 3 in the circumferential direction, and the chord length of the arc-shaped section of the second layer of wave foil 4 is greater than the chord length of the arc-shaped section of the first layer of wave foil 3.

[0032] In the embodiment, the first layer of wave foil 3 and the second layer of wave foil 4 are formed by metal foil through pressing and pressure maintaining molding by the corresponding mold of the structure, such as Figure 4The structure shown is then wound and heat treated by a special tooling Figure 5 The structure ensures that the flat section between each arch is attached to the inner surface of the bearing seat 1, thereby ensuring the consistency and feasibility of the bearing preparation. The design parameters of the chord length and flat section of the first layer wave foil 3 and the second layer wave foil 4 are different, and can be reasonably set according to the design positions of the two, so that the flat section parts of the first layer wave foil 3 and the second layer wave foil 4 are attached without interference. In addition, the arch height of the second layer wave foil 4 is greater than that of the first layer wave foil 3, and there is a gap 203 between each arch, which ensures that the arc sections of the first layer wave foil 3 and the second layer wave foil 4 are stacked and will not interfere due to unreasonable design of the width of the flat section. The implementation of the design scheme of the two layers of wave foils can increase the bearing damping and the deformation degree of the arch foil, and improve the load carrying performance of the arch foil.

[0033] In one embodiment, the flat foils are used to contact the rotating shaft 8, and in the direction from the outside to the inside along the radial direction, the flat foils include the first layer flat foil 5, the second layer flat foil 6 and the third layer flat foil 7 attached in sequence. The circumferential extension direction of the first layer flat foil 5 and the second layer flat foil 6 is opposite to the rotating direction of the rotating shaft 8, and the circumferential extension direction of the second layer flat foil 6 is the same as the rotating direction of the rotating shaft 8.

[0034] The first layer flat foil 5, the second layer flat foil 6 and the third layer flat foil 7 are all whole-circumferential ring structures, so in the preparation and bending process of the bearing, the structural consistency of each foil can be ensured, the overall structure consistency of the gas dynamic pressure bearing can be ensured, and the consistency of the gas dynamic pressure bearing installation can be ensured, thereby improving the load carrying performance of the gas dynamic pressure bearing.

[0035] In one embodiment, the circumferential extension length of the second layer flat foil 6 is 3 / 5-4 / 5 of the entire circumference. As a preferred embodiment, the circumferential extension length of the second layer flat foil 6 is 2 / 3 of the entire circumference. The circumferential end of the second layer flat foil 6 is a slope structure, and the inclined surface of the slope structure faces the third layer flat foil 7.

[0036] In this embodiment, the circumferential direction of the second layer flat foil 6 is opposite to that of the first layer flat foil 5 and the third layer flat foil 7, and this reverse circumferential design is determined based on the rotating direction of the rotating shaft 8. When the rotating shaft 8 starts to rotate, a wedge-shaped area 202 is formed. The design shape and circumferential direction of the intermediate layer are designed based on this point. When the rotating shaft 8 starts to rotate, the top layer flat foil starts to rotate with the rotating shaft 8. At the intermediate layer slope structure, a micro-deformation is generated. By designing the micro-deformation, the radial bearing damping can be increased, thereby improving the overall stiffness and increasing the load carrying performance.

[0037] In the start stage of the high-speed motor operation, the eccentric motion of the rotating shaft 8 during the high-speed rotation causes the rotating shaft 8 and the gas dynamic pressure bearing to form a wedge-shaped area at the intersection of the first layer of foils 5, the second layer of foils 6 and the third layer of foils 7. The high-pressure lubrication gas film formed after the adhesive gas enters the wedge-shaped area provides the bearing-rotating shaft system with a carrying capacity. The second layer of foils 6 rotates with the rotating shaft 8, and the wedge-shaped deformation of the wedge-shaped angle of the tail end of the second layer of foils 6 and the contact area of the third layer of foils 7 is as shown in FIG. 8. Figure 3 The third layer of foils 7 is elastically deformed after the rotation of the rotating shaft 8, and the wedge-shaped area formed is 202. 201 is the gas film between the rotating shaft and the radial gas dynamic pressure bearing. This structure can increase the bearing damping of the radial gas dynamic pressure bearing, improve the anti-wear and impact capacity of the bearing in the start and stop stage, and increase the self-adaptability of the bearing.

[0038] In one embodiment, the second layer of wave foils 4 and the first layer of wave foils 3 each include at least three wave foil segments arranged in sequence in the axial direction, wherein the flat segments and the arc-shaped segments of the wave foil segments at the two axial ends are correspondingly arranged in the circumferential direction, and the wave crests of the wave foil segment in the middle are staggered in the circumferential direction with the wave crests of the wave foil segments at the two axial ends.

[0039] In one embodiment, the wave foil segment includes three segments, wherein the first segment and the third segment are located at the two ends, and the second segment is located in the middle. The length of the first segment and the third segment in the axial direction is the same, and the length of the second segment in the axial direction is the same as the sum of the lengths of the first segment and the third segment in the axial direction, so that the minimum top foil deformation in the axial direction occurs at the axial edge position of the bearing, which can reduce the stiffness of the wave foil at the axial edge of the top foil, that is, increase the local deformation at the axial edge of the top foil, thereby allowing the bearing to have a larger eccentricity and improving the carrying capacity of the bearing.

[0040] In one embodiment, the wave foil segment includes a first wave foil segment 101, a second wave foil segment 102, a third wave foil segment 103 and a fourth wave foil segment 104, wherein the first wave foil segment 101 and the fourth wave foil segment 104 are located at the two axial ends of the bearing seat 1, the second wave foil segment 102 and the third wave foil segment 103 are located between the first wave foil segment 101 and the fourth wave foil segment 104, the flat segments and the arc-shaped segments of the first wave foil segment 101 and the fourth wave foil segment 104 are correspondingly arranged in the circumferential direction, the flat segments and the arc-shaped segments of the second wave foil segment 102 and the third wave foil segment 103 are correspondingly arranged in the circumferential direction, and the wave crests of the first wave foil segment 101 and the second wave foil segment 102 are staggered in the circumferential direction.

[0041] In one embodiment, the first wave foil segment 101, the second wave foil segment 102, the third wave foil segment 103, and the fourth wave foil segment 104 are arranged sequentially at intervals along the axial direction. The first wave foil segment 101, the second wave foil segment 102, the third wave foil segment 103, and the fourth wave foil segment 104 include a fixed end and a free end. The fixed ends of the first wave foil segment 101, the second wave foil segment 102, the third wave foil segment 103, and the fourth wave foil segment 104 are connected together to the bearing seat 1. The circumferential length of the first wave foil segment 101 and the fourth wave foil segment 104 is greater than the circumferential length of the second wave foil segment 102 and the third wave foil segment 103. The free ends of the first wave foil segment 101 and the fourth wave foil segment 104 are fixedly connected by a connecting rod, and the free ends of the second wave foil segment 102 and the third wave foil segment 103 are fixedly connected by a connecting rod.

[0042] When the motor is running at high speed, a high-pressure lubricating gas film 201 is formed in the gap 203 between the pneumatic radial bearing and the shaft 8. The gas pressure in the central area of ​​the radial bearing is higher than the gas pressure at both ends of the radial bearing. The integral radial wave foil arch structure will cause the top foil to undergo through deformation in the opposite direction of the arch, causing the high pressure in the center to leak to both ends. This phenomenon is called end leakage.

[0043] The embodiments of this application employ, as follows: Figure 4 and Figure 5 The structure shown has a four-segment design, with the first corrugated foil 3 and the second corrugated foil 4 consisting of a first corrugated foil segment 101, a second corrugated foil segment 102, a third corrugated foil segment 103, and a fourth corrugated foil segment 104. The first corrugated foil segment 101 and the fourth corrugated foil segment 104 are connected together, while the second corrugated foil segment 102 and the third corrugated foil segment 103 are connected together in the middle, forming a supporting arched foil with a "U"-shaped structure. The corrugated foil units of the first corrugated foil segment 101 and the fourth corrugated foil segment 104 and the corrugated foil units of the second corrugated foil segment 102 and the third corrugated foil segment 103 are staggered to form a variable stiffness arched foil. One end of the first corrugated foil segment 101, the second corrugated foil segment 102, the third corrugated foil segment 103, and the fourth corrugated foil segment 104 is fixed, while the other end is free. The free ends of the first corrugated foil segment 101 and the fourth corrugated foil segment 104 are fixedly connected together, and the free ends of the second corrugated foil segment 102 and the third corrugated foil segment 103 are also fixedly connected together. The fixed ends of the first corrugated foil segment 101, the second corrugated foil segment 102, the third corrugated foil segment 103, and the fourth corrugated foil segment 104 have the same design parameters for arch height, chord length, and flat section. This variable stiffness corrugated foil implementation scheme can effectively improve the end leakage phenomenon of radial bearings and improve the load-bearing performance of gas dynamic radial bearings.

[0044] The four-section wave foil of the gas dynamic pressure radial bearing, the two outer support wave foils at the axial ends and the two inner support wave foils in the middle, can design the stiffness difference of the middle and the two ends according to the motor operation requirements, improve the impact resistance of the bearing, and be beneficial to improve the load stability of the bearing system. The double-layer wave foil structure can effectively increase the stiffness and load capacity of the support wave foil.

[0045] In combination with Figure 1 As shown in the figure, the bearing seat 1 is used to install and support the gas dynamic pressure radial bearing. In this embodiment, after the fixed end of the double-layer wave foil of the gas dynamic pressure radial bearing is inserted into the clamping groove of the bearing seat 1, the locking pin 2 is used for fixation. The fixation mode of the double-layer wave foil is not limited to this. In addition, the locking pin 2 or other structures are also needed to axially fix the gas dynamic pressure radial bearing to avoid axial movement of the gas dynamic pressure radial bearing.

[0046] One end of the first layer wave foil 3, the second layer wave foil 4, the first layer flat foil 5, the second layer flat foil 6 and the third layer flat foil 7 is fixed on the bearing seat 1, and the other end is free, so as to ensure that the foil bearing has deformation and sliding space.

[0047] In one embodiment, the inner surface of the flat foil is sprayed with a high-temperature-resistant lubricating coating, which can play a friction-reducing and wear-resistant lubricating role during the start-stop stage of high-speed operation of the motor.

[0048] According to the embodiments of the present application, the compressor comprises the gas dynamic pressure radial bearing described above.

[0049] According to the embodiments of the present application, the engine comprises the gas dynamic pressure radial bearing described above or the compressor described above.

[0050] It is easy for those skilled in the art to understand that the above-mentioned advantageous modes can be freely combined and superimposed without conflict.

[0051] The above is only the preferred embodiment of the present application, and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above is only the preferred embodiment of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, which should be regarded as the protection scope of the present application.

Claims

1. A gas dynamic pressure radial bearing, characterized by, The bearing seat (1), the second layer wave foil (4), the first layer wave foil (3) and the flat foil are included, the second layer wave foil (4) and the first layer wave foil (3) are stacked and arranged between the bearing seat (1) and the flat foil, the wave crests of the second layer wave foil (4) and the first layer wave foil (3) are arranged correspondingly, and there is a preset gap (203) between the wave crests of the second layer wave foil (4) and the first layer wave foil (3); The second layer wave foil (4) is arranged on the side close to the flat foil, the first layer wave foil (3) is arranged on the side close to the bearing seat (1), and the rigidity of the second layer wave foil (4) is smaller than that of the first layer wave foil (3); The flat foil is used for contacting with the rotating shaft (8), and along the radial direction from outside to inside, the flat foil includes the first layer flat foil (5), the second layer flat foil (6) and the third layer flat foil (7) arranged in sequence, the circumferential extension direction of the first layer flat foil (5) and the second layer flat foil (6) is opposite to the rotating direction of the rotating shaft (8), and the circumferential extension direction of the second layer flat foil (6) is the same as the rotating direction of the rotating shaft (8). The circumferential extension length of the second layer flat foil (6) is 3 / 5-4 / 5 of the whole circumference.

2. The aerodynamic radial bearing of claim 1, wherein, The second layer wave foil (4) and the first layer wave foil (3) each include a flat section and an arc section, the flat section of the second layer wave foil (4) is supported on the flat section of the first layer wave foil (3), the width of the flat section of the second layer wave foil (4) in the circumferential direction is smaller than the width of the flat section of the first layer wave foil (3) in the circumferential direction, and the chord length of the arc section of the second layer wave foil (4) is greater than the chord length of the arc section of the first layer wave foil (3).

3. The aerodynamic radial bearing of claim 1, wherein, The first layer flat foil (5), the second layer flat foil (6) and the third layer flat foil (7) each are an integral circumferential structure.

4. The aerodynamic radial bearing of claim 1, wherein, The circumferential extension length of the second layer flat foil (6) is 2 / 3 of the whole circumference.

5. The aerodynamic radial bearing of claim 1, wherein, The circumferential end of the second layer flat foil (6) is a slope structure, and the inclined surface of the slope structure faces the third layer flat foil (7).

6. The gas dynamic pressure radial bearing according to any one of claims 1 to 5, characterized in that, The second layer wave foil (4) and the first layer wave foil (3) each include at least three wave foil sections arranged in sequence in the axial direction, wherein the flat sections and the arc sections of the wave foil sections at both ends in the axial direction are arranged correspondingly in the circumferential direction, and the wave crests of the wave foil section in the middle and the wave crests of the wave foil sections at both ends in the axial direction are arranged alternately in the circumferential direction.

7. The gas dynamic pressure radial bearing of claim 6, wherein, The wave foil section comprises a first wave foil section (101), a second wave foil section (102), a third wave foil section (103) and a fourth wave foil section (104), wherein the first wave foil section (101) and the fourth wave foil section (104) are located at the axial ends of the bearing housing (1), the second wave foil section (102) and the third wave foil section (103) are located between the first wave foil section (101) and the fourth wave foil section (104), the flat sections and the arc-shaped sections of the first wave foil section (101) and the fourth wave foil section (104) are correspondingly arranged in the circumferential direction, the flat sections and the arc-shaped sections of the second wave foil section (102) and the third wave foil section (103) are correspondingly arranged in the circumferential direction, and the wave crests of the first wave foil section (101) and the second wave foil section (102) are staggered in the circumferential direction.

8. The gas dynamic pressure radial bearing of claim 7, wherein, The first wave foil section (101), the second wave foil section (102), the third wave foil section (103) and the fourth wave foil section (104) are sequentially and spacedly arranged in the axial direction, the first wave foil section (101), the second wave foil section (102), the third wave foil section (103) and the fourth wave foil section (104) comprise fixed ends and free ends, the fixed ends of the first wave foil section (101), the second wave foil section (102), the third wave foil section (103) and the fourth wave foil section (104) are commonly connected to the bearing housing (1), the circumferential length of the first wave foil section (101) and the fourth wave foil section (104) is greater than the circumferential length of the second wave foil section (102) and the third wave foil section (103), the free ends of the first wave foil section (101) and the fourth wave foil section (104) are fixedly connected through a connecting rod, and the free ends of the second wave foil section (102) and the third wave foil section (103) are fixedly connected through a connecting rod.

9. The gas dynamic pressure radial bearing of claim 1, wherein, The inner surface of the flat foil is sprayed with a high-temperature-resistant lubricating coating.

10. A compressor comprising a gas dynamic pressure radial bearing, characterized in that, The gas dynamic pressure radial bearing is the gas dynamic pressure radial bearing according to any one of claims 1 to 9.

11. An engine characterized by, The compressor comprises the gas dynamic pressure radial bearing according to any one of claims 1 to 9 or the compressor according to claim 10.

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