Foil dynamic pressure gas radial bearing

Abstract

The invention discloses a foil dynamic pressure gas radial bearing which comprises a bearing shell, a rotating shaft, a top foil, a bump foil and a tile block assembly, a cavity is formed in the bearing shell in the axial direction, the rotating shaft is arranged in the cavity in the axial direction, the bump foil and the top foil are arranged between the bearing shell and the rotating shaft in the axial direction, and the tile block assembly is arranged between the bump foil and the top foil. The tile block assembly is arranged in the non-bearing area of the bearing shell and avoids the bump foil and the top foil, and the outer wall of the rotating shaft, the top foil and the inner wall of the tile block assembly form a fit clearance at the same time; a first gas channel used for generating a static pressure gas film between the tile block assembly and the rotating shaft is arranged in the tile block assembly. According to the bearing disclosed by the invention, the tile block assembly is arranged on the bearing shell, and the first gas channel for generating the static pressure gas film between the tile block assembly and the rotating shaft is arranged in the tile block assembly, so that the gas film with certain pressure is formed in the non-bearing area to support the rotating shaft, and the whole bearing rotates more stably.

Description

Technical Field

[0001] The present invention relates to the technical field of precision instruments, and in particular to a foil dynamic pressure gas radial bearing. Background Art

[0002] As a typical sliding bearing, the foil dynamic pressure gas radial bearing uses a gaseous medium to form a dynamic pressure air film between the shaft and the foil to achieve contactless support for the rotor. This type of bearing has significant advantages such as high speed, low friction, high temperature resistance, and no need for lubrication. It has been widely used in high-precision, high-speed rotating equipment such as high-speed centrifuges, low-temperature refrigeration centrifugal compressors, micro gas turbines, air compressors, and turbochargers. In the prior art, due to the uneven distribution of the gap between the bearings in the circumferential direction, a negative pressure air film is easily formed in the non-load-bearing area. This area cannot effectively suppress the vibration of the rotating shaft, which causes the rotor to become unstable when subjected to excitations such as unbalanced loads, misalignment, and fluid disturbances, and even mechanical contact between the rotating shaft and the bearing occurs, affecting the operating stability and service life of the bearing. Therefore, there is an urgent need for a foil dynamic pressure gas radial bearing structure that can improve the stability of the air film. Summary of the Invention

[0003] The purpose of the present invention is to provide a foil dynamic pressure gas radial bearing, aiming to solve the problem in the prior art that the bearing is prone to form a negative pressure gas film in the non-load-bearing area, resulting in instability.

[0004] In order to solve the above technical problems, the purpose of the present invention is achieved through the following technical solutions: providing a foil dynamic pressure gas radial bearing, comprising a bearing housing, a rotating shaft, a top foil, a corrugated foil, and a pad assembly, wherein a cavity is axially arranged inside the bearing housing, the rotating shaft is axially arranged in the cavity, the corrugated foil and the top foil are axially arranged between the bearing housing and the rotating shaft, the pad assembly is arranged in the non-load-bearing area of the bearing housing and avoids the corrugated foil and the top foil, the outer wall of the rotating shaft forms a fitting gap with the top foil and the inner wall of the pad assembly at the same time, and a first gas channel for generating a static pressure gas film between the pad assembly and the rotating shaft is arranged inside the pad assembly.

[0005] Furthermore, the pad assembly includes a bearing pad and a throttle pad, a bearing pad fixing groove is opened on the inner wall of the bearing housing, the bearing pad is arranged in the bearing pad fixing groove, the throttle pad is connected to the side of the bearing pad close to the rotating shaft, the first gas channel includes a bearing pad hole opened on the bearing pad and a throttle pad hole opened on the throttle pad, and the bearing pad hole is connected to the throttle pad hole.

[0006] Furthermore, the bearing pad is swingably arranged in the bearing pad fixing groove, and a swing gap is provided between the two sides of the bearing pad along the axial direction and the groove edge of the bearing pad fixing groove, and the bearing pad can swing around the axial center axis in the swing gap.

[0007] Furthermore, the throttle shoe is made of graphite, metal or ceramic.

[0008] Furthermore, the pad assembly also includes a fastener, the bearing housing is provided with a connecting hole along the center axis, the fastener is flexibly connected to the bearing pad through the connecting hole, and the first gas channel also includes a fastener hole opened on the fastener, and the fastener hole is connected to the bearing pad hole.

[0009] Furthermore, the inner wall and outer wall of the bearing pad, the inner wall and outer wall of the throttle pad and the inner wall of the bearing pad fixing groove are all arranged in an arc shape.

[0010] Furthermore, a dynamic pressure inlet hole and a dynamic pressure outlet hole are provided on the bearing housing, and the dynamic pressure inlet hole and the dynamic pressure outlet hole are respectively located on both sides of the axial direction of the shoe assembly. The dynamic pressure inlet hole, the fitting clearance and the dynamic pressure outlet hole are connected in sequence to form a second gas channel.

[0011] Furthermore, a non-through air inlet groove and a through air outlet groove are axially provided on the bearing housing, the dynamic pressure air inlet hole is provided on the air inlet groove, and the dynamic pressure air outlet hole is provided on the air outlet groove.

[0012] Furthermore, a plurality of the dynamic pressure air inlet holes and the dynamic pressure air outlet holes are provided, and the plurality of the dynamic pressure air inlet holes and the dynamic pressure air outlet holes are arranged at intervals in the corresponding air inlet groove and the air outlet groove.

[0013] Furthermore, the inner wall of the bearing housing is provided with first insertion grooves on both sides along the axial direction, and the two first insertion grooves are respectively located on the outside of the dynamic pressure inlet hole and the dynamic pressure outlet hole, and the two ends of the top foil are respectively inserted into the corresponding first insertion grooves, and the inner wall of the bearing housing is provided with at least one second insertion groove along the axial direction, and at least one end of the wave foil is inserted into the second insertion groove.

[0014] The present invention provides a foil dynamic pressure gas radial bearing, comprising a bearing housing, a rotating shaft, a top foil, a bump foil, and a pad assembly. The bearing housing is provided with an axially arranged cavity, the rotating shaft is axially arranged in the cavity, the bump foil and the top foil are axially arranged between the bearing housing and the rotating shaft, the pad assembly is arranged in a non-load-bearing area of the bearing housing and avoids the bump foil and the top foil, the outer wall of the rotating shaft forms a fitting gap with the top foil and the inner wall of the pad assembly, and a first gas channel for generating a static pressure gas film between the pad assembly and the rotating shaft is provided inside the pad assembly. The present invention arranges a pad assembly on the bearing housing, and a first gas channel for generating a static pressure gas film between the pad assembly and the rotating shaft is provided inside the pad assembly. In this way, an air film with a certain pressure is formed in the non-load-bearing area, providing support for the rotating shaft, so that the entire bearing rotates more smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a structural diagram of a foil dynamic pressure gas radial bearing in the prior art;

[0017] Figure 2 for Figure 1 Enlarged view of part a;

[0018] Figure 3 A schematic diagram of the structure of a foil dynamic pressure gas radial bearing provided by an embodiment of the present invention Figure 1 ;

[0019] Figure 4 A schematic diagram of the structure of a foil dynamic pressure gas radial bearing provided by an embodiment of the present invention Figure 2 ;

[0020] Figure 5 for Figure 4 Cross-sectional view of AA;

[0021] Figure 6 A schematic diagram of the structure of a foil dynamic pressure gas radial bearing provided by an embodiment of the present invention Figure 3 ;

[0022] Figure 7 for Figure 6 Cross-sectional view of the middle BB;

[0023] Figure 8 for Figure 7Enlarged view of part C;

[0024] Figure 9 Schematic diagram of the structure of the bearing housing provided in the embodiment of the present invention Figure 1 ;

[0025] Figure 10 for Figure 9 Cross-sectional view of the middle DD;

[0026] Figure 11 Schematic diagram of the structure of the bearing housing provided in the embodiment of the present invention Figure 2 .

[0027] Description of the symbols in the figure:

[0028] 1. Bearing housing; 2. Rotating shaft; 3. Top foil; 4. Corrugated foil; 5. Air film convergence area; 6. Wedge-shaped divergence area; 7. Dynamic pressure air film;

[0029] 10. Bearing housing; 11. Cavity; 12. Bearing shoe fixing groove; 13. Connecting hole; 14. Dynamic pressure air inlet; 15. Dynamic pressure air outlet; 16. Air inlet groove; 17. Air outlet groove; 18. First insertion groove; 19. Second insertion groove;

[0030] 20. Rotating shaft;

[0031] 30. Top foil;

[0032] 40. Wave foil;

[0033] 50. Pad assembly; 51. Bearing pad; 511. Bearing pad hole; 52. Restrictor pad; 53. Fastener; 531. Fastener hole;

[0034] 100, dynamic pressure inlet area; 200, wedge-shaped compression area; 300, dynamic pressure air film; 400, wedge-shaped divergence area; 500, dynamic pressure outlet area; 600, static pressure inlet area; 700, static pressure air film. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0037] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0038] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0039] Combine Figure 1 and Figure 2 As shown, Figure 1 and Figure 2 The direction of the arrow in the figure is the direction of rotation of the shaft. The foil dynamic pressure gas radial bearing in the prior art usually includes components such as a bearing housing 1, a shaft 2, a top foil 3, and a wave foil 4. The wave foil 4 is an elastic supporting element with a corrugated structure, which provides the main stiffness and partial damping through its elastic deformation; the top foil 3 is a flexible foil overlapped on the wave foil 4, which is used to form a dynamic pressure gas film between the shaft 2. During actual operation, the shaft 2 will be eccentric under the action of gravity, so that a wedge-shaped gas film structure (i.e., the gas film convergence area 5 and the wedge-shaped divergence area 6) is formed on the inner surface of the bearing, which converges on one side and diverges on the other side. When the shaft 2 rotates at high speed, the gas is compressed in the gas film convergence area 5 to form a positive pressure gas film with supporting capacity (i.e., the dynamic pressure gas film 7); while in the wedge-shaped divergence area 6, due to the continuous increase in the gas film space, the gas pressure decays rapidly, forming a negative pressure gas film that cannot provide effective support for the shaft 2.

[0040] Combine Figure 3 As shown, an embodiment of the present invention provides a foil dynamic pressure gas radial bearing, including a bearing housing 10, a rotating shaft 20, a top foil 30, a bump foil 40, and a pad assembly 50. A cavity 11 is axially arranged inside the bearing housing 10, the rotating shaft 20 is axially arranged in the cavity 11, the bump foil 40 and the top foil 30 are axially arranged between the bearing housing 10 and the rotating shaft 20, the pad assembly 50 is arranged in the non-load-bearing area of the bearing housing 10 and avoids the bump foil 40 and the top foil 30, the outer wall of the rotating shaft 20 forms a fitting gap with the top foil 30 and the inner wall of the pad assembly 50 at the same time, and a first gas channel for generating a static pressure gas film between the pad assembly 50 and the rotating shaft 20 is arranged inside the pad assembly 50.

[0041] In this embodiment, the bearing housing 10 is a hollow rotary structure, in which a cavity 11 for mounting the rotating shaft 20 is axially arranged. The rotating shaft 20 is arranged axially in the cavity 11 and rotates at high speed around its own axis during operation. The wave foil 40 and the top foil 30 are both flexible elastic elements arranged axially and arranged between the bearing housing 10 and the rotating shaft 20. Specifically, the wave foil 40 is an elastic sheet with a corrugated deformation structure, one end of which is embedded in a preset notch in the bearing housing 10, and the other end can be freely suspended. The top foil 30 is a sleeve-like structure, with both ends inserted into the preset grooves in the bearing housing 10 and overlapped on the wave crest of the wave foil 40 in the radial direction. The wave foil 40 and the top foil 30 are used to support the rotating shaft 20 to achieve contactless operation in the bearing load-bearing area.

[0042] Furthermore, the pad assembly 50 is disposed in the non-load bearing area (eg Figure 3 The inner cavity area above the rotating shaft 20) is the area where the bump foil 40 and the top foil 30 are not arranged. The pad assembly 50 is arranged to avoid the bump foil 40 and the top foil 30. A fitting gap is provided between the inner side surface of the pad assembly 50 and the outer side surface of the rotating shaft 20 to form a static pressure air film to provide support for the rotating shaft 20 in the non-load-bearing area. To achieve static pressure support, a first gas channel is provided inside the pad assembly 50 to introduce external gas into the fitting gap area between the pad assembly 50 and the rotating shaft 20 to form a static pressure air film with a certain pressure. The pad assembly 50 can introduce external gas through the first gas channel to establish a static pressure air film between the pad assembly 50 and the rotating shaft 20. The static pressure air film provides positive pressure support for the rotating shaft 20, filling the negative pressure area that originally appeared in the non-load-bearing area of the bearing, thereby forming support for the rotating shaft 20 in various areas around the bearing, improving the stability of the rotating shaft 20's rotation, avoiding the rotating shaft 20 from becoming unstable or vibrating excessively due to lack of support on the upper part, and preventing the rotating shaft 20 from contacting and wearing with the bearing housing 10.

[0043] Combine Figures 4 to 8 As shown, in one embodiment, the pad assembly 50 includes a bearing pad 51 and a throttle pad 52, a bearing pad fixing groove 12 is opened on the inner wall of the bearing housing 10, the bearing pad 51 is arranged in the bearing pad fixing groove 12, and the throttle pad 52 is connected to the side of the bearing pad 51 close to the rotating shaft 20, and the first gas channel includes a bearing pad hole 511 opened on the bearing pad 51 and a throttle pad hole opened on the throttle pad 52, and the bearing pad hole 511 is connected to the throttle pad hole.

[0044] In this embodiment, the inner wall of the bearing housing 10 is provided with a bearing pad retaining groove 12 for positioning and mounting the bearing pad 51. The bearing pad 51 is assembled within the bearing pad retaining groove 12 and connected to the bearing housing 10. The throttle pad 52 is disposed on the side of the bearing pad 51 closest to the rotating shaft 20, and the two can be fixedly connected by means such as bonding. The bearing pad hole 511 is connected to the throttle pad hole, forming a continuous gas passage structure. External gas enters the bearing pad hole 511 and is then directed into the throttle pad hole from the bearing pad hole 511. External gas can enter the interior of the throttle pad 52 through the bearing pad hole 511. After being throttled by the throttle pad 52, the external gas evenly overflows through the throttle pad hole from the side closest to the rotating shaft 20, forming a stable static pressure gas film on the outer surface of the rotating shaft 20, which supports and lubricates the rotating shaft 20. Thus, the bearing pad 51 provides structural support and installation positioning, and the throttle pad 52 throttles and distributes the airflow. The combination of the two forms a static pressure gas bearing structure, which can provide static pressure support for the rotating shaft 20 in the non-load-bearing area of the bearing.

[0045] In one embodiment, the bearing pad 51 is swingably arranged in the bearing pad fixing groove 12, and a swing gap is provided between the two sides of the bearing pad 51 along the axial direction and the groove edge of the bearing pad fixing groove 12. The bearing pad 51 can swing around the axial center axis in the swing gap.

[0046] In this embodiment, the bearing pad 51 is swingably disposed within the bearing pad retaining groove 12 on the inner wall of the bearing housing 10. Specifically, swing clearances are reserved between the ends of the bearing pad 51 and the edges of the bearing pad retaining groove 12 along the axial direction, allowing the bearing pad 51 to freely swing relative to the axial center axis of the bearing pad retaining groove 12. The swing clearances provided between the two axial sides of the bearing pad 51 and the walls of the bearing pad retaining groove 12 ensure that the bearing pad 51 is not rigidly fixed within the groove, but rather can tilt and swing at a small angle about its axial center axis within the clearances.

[0047] Further, Figure 4 The direction of the arrow in the figure is the direction of rotation of the shaft. Figure 7 The direction of the arrow in the figure is the flow direction of the dynamic pressure gas. Figure 8 The direction of the arrow is the flow direction of the static pressure gas. Figure 7 The dynamic pressure gas in the fluid enters the dynamic pressure inlet area 100, then flows through the wedge-shaped compression area 200 for wedge-shaped compression, thereby forming a dynamic pressure gas film 300 at the bottom, then flows through the wedge-shaped divergent area 400 for wedge-shaped divergence, and finally enters the dynamic pressure outlet area 500 for outlet, which can take away some heat. Figure 8The static pressure gas in the static pressure inlet area 600 enters the static pressure inlet area 600, generating a static pressure gas film 700 that acts on the rotating shaft 20. Of course, the static pressure inlet area 600 can be connected to the intake pipe to provide continuous, high-pressure gas. In actual applications, the intake pipe generally integrates high-pressure gas generation equipment, filtering equipment, drying equipment, one-way valve, pressure regulating valve, and connecting pipes.

[0048] The tilting pad structure design described above allows the bearing pad 51 to automatically adjust its position as the shaft 20 changes position. For example, when the rotational speed of the shaft 20 changes the position or pressure distribution of the dynamic pressure film 300 formed beneath it, the bearing pad 51 can tilt accordingly around its central axis within the swing gap, adjusting the position and pressure of the static pressure film 700 it generates, thereby consistently matching the dynamic pressure film 300 and providing continuous and effective support for the shaft 20. During operation, the shaft 20 rotates at high speed under the influence of the electromagnetic field. The shaft 20 is stably suspended by the dynamic pressure film 300 and the static pressure film 700 on its upper and lower sides, reducing vibration during operation and avoiding instability that could be caused by a lack of support in the non-load-bearing area.

[0049] In one embodiment, the restrictor shoe 52 is made of graphite, metal, or ceramic.

[0050] In this embodiment, the throttle pad 52 can be made of a high-hardness material with a porous structure or microporous channels, such as graphite, metal, or ceramic. In practical applications, the throttle pad 52 can also be made of a ceramic porous structure, a metal sintered microporous structure, or other structures with throttling properties such as micropores, shallow cavities, or small holes, depending on different application requirements. For example, the throttle pad 52 can be made of porous ceramic or porous metal, or it can be provided with a number of tiny holes, slits, or shallow cavities as a throttling mechanism. The use of these materials and structures can produce a robust throttling and pressure-reducing effect on the high-pressure gas entering the throttle pad 52: after passing through the porous medium or micropores, the high-pressure gas overflows from the surface of the throttle pad 52 at a uniformly distributed and appropriate pressure, forming a uniform and stable static pressure film 700 on the surface of the rotating shaft 20. This design ensures stable pressure and thickness of the static pressure film, further improving the bearing's load-bearing capacity and operating stability.

[0051] In one embodiment, the pad assembly 50 also includes a fastener 53, and the bearing housing 10 is provided with a connecting hole 13 along the central axis. The fastener 53 is flexibly connected to the bearing pad 51 through the connecting hole 13. The first gas channel also includes a fastener hole 531 opened on the fastener 53, and the fastener hole 531 is connected to the bearing pad hole 511.

[0052] In this embodiment, the bearing housing 10 has a connecting hole 13 defined along its central axis. A fastener 53 (e.g., a hollow screw) passes through the connecting hole 13 and connects to the bearing pad 51, thereby retaining the bearing pad 51 within the bearing pad retaining groove 12. The fastener 53 positions and supports the bearing pad 51. Its connection is flexible, allowing the bearing pad 51 to still experience slight oscillation (i.e., tilting) within the bearing pad retaining groove 12 even after being tightened. Furthermore, the fastener 53 has a through-hole 531 defined therein, which serves as part of the first gas passage. The connecting hole 13, the fastener hole 531, and the bearing pad hole 511 communicate with each other, forming a gas supply path from the bearing exterior to the interior of the pad assembly 50. During operation, external high-pressure gas can sequentially pass through the connecting hole 13, the fastener hole 531, and the bearing pad hole 511 of the bearing housing 10 and enter the throttle pad 52, thereby establishing a stable static pressure gas film 700 between the pad assembly 50 and the rotating shaft 20.

[0053] In one embodiment, the inner and outer walls of the bearing pad 51, the inner and outer walls of the throttle pad 52, and the inner wall of the bearing pad fixing groove 12 are all arc-shaped.

[0054] In this embodiment, the inner and outer walls of the bearing pad 51, the inner and outer walls of the throttle pad 52, and the inner wall of the bearing pad retaining groove 12 all feature an arcuate design. Specifically, the bearing pad 51's surface facing the shaft 20 and the surface facing away from the shaft 20 are both arcuately centered with the bearing center. The inner surface (facing the shaft 20) and outer surface (the surface that contacts the bearing pad 51) of the throttle pad 52 are also arcuately shaped. Furthermore, the inner wall of the bearing pad retaining groove 12 is machined to a curved profile that matches the outer curved surface of the bearing pad 51. This matching of these curved surfaces allows the pad assembly 50 to fit tightly within the cylindrical interior of the bearing housing 10. On the one hand, the contact between the bearing pad 51 and the bearing pad fixing groove 12 is a curved surface fit, ensuring the stability and positioning accuracy of the bearing pad 51 during swing adjustment within the groove. On the other hand, the inner arc surface of the throttle pad 52 forms a uniform fit clearance with the outer circumferential surface of the rotating shaft 20, ensuring that the static pressure air film 700 is evenly formed between the pad assembly 50 and the rotating shaft 20, avoiding uneven air film thickness or leakage caused by mismatched contact surfaces. In summary, the use of the arc-shaped pad assembly 50 and the bearing pad fixing groove 12 improves the assembly security and air film stability.

[0055] Combine Figures 9 to 11 As shown, in one embodiment, a dynamic pressure inlet hole 14 and a dynamic pressure outlet hole 15 are provided on the bearing housing 10. The dynamic pressure inlet hole 14 and the dynamic pressure outlet hole 15 are respectively located on both sides of the axial direction of the shoe assembly 50. The dynamic pressure inlet hole 14, the fitting clearance and the dynamic pressure outlet hole 15 are connected in sequence to form a second gas channel.

[0056] In this embodiment, the bearing housing 10 is provided with a dynamic pressure inlet hole 14 and a dynamic pressure outlet hole 15 at both ends of the position where the pad assembly 50 is located in the axial direction. The dynamic pressure inlet hole 14 and the dynamic pressure outlet hole 15 are respectively located at the two opposite end faces of the bearing housing 10 (i.e., at the positions on both sides of the axial direction of the pad assembly 50), and the two are connected in sequence through the fitting clearance inside the bearing to form a second gas channel. By setting up the second gas channel, forced convection of gas entering from one side and being discharged from the other side inside the foil dynamic pressure gas radial bearing is achieved. This axial through-ventilation design strengthens the circulation of circumferential gas inside the bearing, avoids gas retention or repeated circulation inside the bearing, thereby being able to promptly remove the heat generated by the high-speed rotation of the shaft, significantly improving the cooling effect of the bearing, and enabling the bearing to operate reliably under higher speed and higher temperature conditions.

[0057] In one embodiment, a non-through air inlet groove 16 and a through air outlet groove 17 are axially provided on the bearing housing 10 , the dynamic pressure air inlet hole 14 is provided on the air inlet groove 16 , and the dynamic pressure air outlet hole 15 is provided on the air outlet groove 17 .

[0058] In this embodiment, in order to cooperate with the introduction of the above-mentioned second gas channel, an air inlet groove 16 and an air outlet groove 17 are provided on the bearing housing 10 for guiding the air flow. The inner wall of the bearing housing 10 is provided with an incomplete air inlet groove 16 and a through air outlet groove 17 along the axial direction. The air inlet groove 16 is a blind groove in the axial direction (its two ends are in a closed state in the bearing housing 10), while the air outlet groove 17 is a through groove that runs through the entire axial length of the bearing housing 10. The provision of the air inlet groove 16 allows the gas entering through the dynamic pressure air inlet hole 14 to first be collected in the groove cavity inside the bearing cavity: since the air inlet groove 16 is not a through structure, the incoming gas will not directly leak out from the axial ends, but can only enter the interior of the bearing through the fitting clearance, thereby being effectively utilized; at the same time, the relatively wide groove cavity of the air inlet groove 16 can buffer and rectify the high-speed incoming airflow, reduce the airflow speed and disturbance, and facilitate the smooth formation of the dynamic pressure air film 300. Conversely, outlet grooves 17 extend through both ends of the bearing housing 10 and communicate with the dynamic pressure outlet holes 15. Gas within the bearing flows through the clearance between the outlet grooves 17 and can then be smoothly discharged from both ends of the bearing. A portion of the gas flows radially out through the dynamic pressure outlet holes 15, while the remainder exits the bearing along the axial path of the outlet grooves 17. The coordinated arrangement of the inlet grooves 16 and outlet grooves 17 effectively guides airflow in and out of the bearing: the inlet path is located within the bearing, preventing direct short-circuiting of the airflow, while the outlet path is continuous to ensure unimpeded exhaust, further improving the efficiency of air circulation and cooling within the bearing.

[0059] During operation, external gas enters the bearing from the dynamic pressure air inlet hole 14 at one end, and first enters the spatial area of the air inlet groove 16 in the bearing housing 10. Since the volume of the air inlet groove 16 is much larger than the aperture of the dynamic pressure air inlet hole 14, the gas expands rapidly after entering, and the flow rate decreases, thereby preventing the high-speed airflow from directly impacting the rotating shaft 20 and the foil (i.e., the top foil 30 and the wave foil 40). Subsequently, driven by the high-speed rotation of the rotating shaft 20, the airflow flows circumferentially along the inner cavity of the bearing: in the lower area of the bearing, the airflow is squeezed into the gradually narrowing wedge-shaped compression zone 200 by the rotating shaft 20, and the pressure rises rapidly, forming a dynamic pressure air film 300 to support the rotating shaft 20; continuing to flow in the direction of rotation, the space in the upper area of the bearing gradually expands, the airflow pressure decreases, and a wedge-shaped divergent zone 400 is formed. At this time, the airflow completes a cycle and becomes the gas in the dynamic pressure outlet zone 500, which is discharged from the dynamic pressure outlet hole 15 at the other end.

[0060] In one embodiment, a plurality of dynamic pressure air inlet holes 14 and a plurality of dynamic pressure air outlet holes 15 are provided, and the plurality of dynamic pressure air inlet holes 14 and dynamic pressure air outlet holes 15 are arranged at intervals in the corresponding air inlet grooves 16 and air outlet grooves 17 .

[0061] In this embodiment, the dynamic pressure air inlet 14 and the dynamic pressure air outlet 15 are both arranged in multiple ways. Multiple dynamic pressure air inlet holes 14 are arranged at intervals along the length direction of the air inlet groove 16, and multiple dynamic pressure air outlet holes 15 are arranged at intervals along the length direction of the air outlet groove 17. For example, a number of openings can be evenly distributed in the air inlet groove 16 and the air outlet groove 17, respectively, as the dynamic pressure air inlet 14 and the dynamic pressure air outlet 15. Through the design of multi-point air intake and multi-point exhaust, the gas can enter and flow out of the bearing cavity evenly at both ends of the bearing axial direction: on the one hand, fresh cooling air flow can be obtained at all points in the width direction of the bearing, avoiding local overheating caused by air intake at a single position; on the other hand, the dynamic pressure air outlet 15 disperses the exhaust to prevent single-point exhaust from causing air flow concentration or pressure abnormality in a certain place. As a result, the dynamic pressure air film 300 inside the bearing is more evenly distributed along the axial direction, and the heat dissipation and stability of the bearing are further improved.

[0062] In one embodiment, the inner wall of the bearing housing 10 is provided with first insertion grooves 18 on both sides along the axial direction, and the two first insertion grooves 18 are respectively located on the outside of the dynamic pressure inlet hole 14 and the dynamic pressure outlet hole 15, and the two ends of the top foil 30 are respectively inserted into the corresponding first insertion grooves 18, and the inner wall of the bearing housing 10 is provided with at least one second insertion groove 19 along the axial direction, and at least one end of the wave foil 40 is inserted into the second insertion groove 19.

[0063] In this embodiment, the top foil 30 and the bump foil 40 are installed using an insertion groove fixation method. The inner wall of the bearing housing 10 is provided with first insertion grooves 18 on both sides of the axial direction, located outside the dynamic pressure inlet hole 14 and the dynamic pressure outlet hole 15 relative to the axial direction, for fixing the two ends of the top foil 30. The two ends of the top foil 30 are respectively inserted into the corresponding first insertion grooves 18 and are tightly clamped, thereby stably fixing the top foil 30 to the inner cavity of the bearing housing 10. Preferably, the ends of the top foil 30 can be inserted into the notch using a double-folded structure to increase the contact area and friction between it and the inner wall of the first insertion groove 18, further improving the reliability of the fixation.

[0064] Furthermore, the inner wall of the bearing housing 10 is provided with at least one second insertion slot 19 along the axial direction for mounting and fixing the bump foil 40. At least one end of the bump foil 40 is inserted into and fixed in the second insertion slot 19, while the other end remains free (not fixed to the bearing housing 10), thereby retaining space for the bump foil 40 to elastically deform under load. Through the aforementioned insertion slot structure, the top foil 30 and the bump foil 40 are positioned within the bearing housing 10, preventing them from loosening or shifting even under high-speed rotation conditions. At the same time, because the top foil 30 and the bump foil 40 do not completely surround the entire bearing, a gap is formed in the non-load-bearing area above the bearing where the foil is missing, leaving space for the arrangement of the pad assembly 50. This segmented installation method of the foil ensures that the foil dynamic pressure gas radial bearing uses the top foil 30 and the bump foil 40 to generate a dynamic pressure gas film 300 in the lower area, and the pad assembly 50 to generate a static pressure gas film 700 in the upper area. The two complement each other and together provide stable support for the rotating shaft 20.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A foil dynamic pressure gas radial bearing, characterized in that: It includes a bearing housing, a rotating shaft, a top foil, a bump foil, and a pad assembly. A cavity is axially arranged inside the bearing housing. The rotating shaft is axially arranged in the cavity. The bump foil and the top foil are axially arranged between the bearing housing and the rotating shaft. The pad assembly is arranged in the non-load-bearing area of the bearing housing and avoids the bump foil and the top foil. The outer wall of the rotating shaft forms a fitting gap with the top foil and the inner wall of the pad assembly. A first gas channel for generating a static pressure air film between the pad assembly and the rotating shaft is arranged inside the pad assembly.

2. The foil dynamic pressure gas radial bearing according to claim 1, characterized in that: The pad assembly includes a bearing pad and a throttle pad. A bearing pad fixing groove is provided on the inner wall of the bearing housing. The bearing pad is arranged in the bearing pad fixing groove. The throttle pad is connected to the side of the bearing pad close to the rotating shaft. The first gas channel includes a bearing pad hole provided on the bearing pad and a throttle pad hole provided on the throttle pad. The bearing pad hole is connected to the throttle pad hole.

3. The foil dynamic pressure gas radial bearing according to claim 2, characterized in that: The bearing pad is swingably arranged in the bearing pad fixing groove, and a swing gap is provided between the two sides of the bearing pad and the groove edge of the bearing pad fixing groove along the axial direction. The bearing pad can swing around the axial center axis in the swing gap.

4. The foil dynamic pressure gas radial bearing according to claim 2, characterized in that: The throttle shoe is made of graphite, metal or ceramic.

5. The foil dynamic pressure gas radial bearing according to claim 3, characterized in that: The pad assembly also includes a fastener, the bearing housing is provided with a connecting hole along the central axis, the fastener is flexibly connected to the bearing pad through the connecting hole, and the first gas channel also includes a fastener hole opened on the fastener, and the fastener hole is connected to the bearing pad hole.

6. The foil dynamic pressure gas radial bearing according to claim 2, characterized in that: The inner wall and outer wall of the bearing pad, the inner wall and outer wall of the throttle pad and the inner wall of the bearing pad fixing groove are all arranged in an arc shape.

7. The foil dynamic pressure gas radial bearing according to claim 1, characterized in that: The bearing housing is provided with a dynamic pressure inlet hole and a dynamic pressure outlet hole, which are respectively located on both sides of the axial direction of the shoe assembly. The dynamic pressure inlet hole, the fitting clearance and the dynamic pressure outlet hole are connected in sequence to form a second gas channel.

8. The foil dynamic pressure gas radial bearing according to claim 7, characterized in that: The bearing housing is provided with a non-through air inlet groove and a through air outlet groove in the axial direction. The dynamic pressure air inlet hole is provided on the air inlet groove, and the dynamic pressure air outlet hole is provided on the air outlet groove.

9. The foil dynamic pressure gas radial bearing according to claim 8, characterized in that: There are multiple dynamic pressure air inlet holes and multiple dynamic pressure air outlet holes, and the multiple dynamic pressure air inlet holes and dynamic pressure air outlet holes are arranged at intervals in the corresponding air inlet groove and air outlet groove.

10. The foil dynamic pressure gas radial bearing according to claim 7, characterized in that: The inner wall of the bearing housing is provided with first insertion grooves on both sides along the axial direction, and the two first insertion grooves are respectively located on the outside of the dynamic pressure inlet hole and the dynamic pressure outlet hole, and the two ends of the top foil are respectively inserted into the corresponding first insertion grooves, and the inner wall of the bearing housing is provided with at least one second insertion groove along the axial direction, and at least one end of the corrugated foil is inserted into the second insertion groove.

Images