Gas foil bearing with discontinuous gas film

Abstract

The application provides a gas film discontinuous dynamic pressure gas foil bearing, which comprises a bearing seat, an elastic supporting foil and a top foil; the elastic supporting foil and the top foil are arranged in the bearing seat; the elastic supporting foil is arranged between the bearing seat and the top foil; and air holes are formed in the top foil. The application breaks the continuity of the gas film in the circumferential direction by forming the air holes in the top foil, effectively inhibits the gas film vortex and the gas film instability, and significantly improves the running stability of the bearing at high speed.

Description

Technical Field

[0001] This invention relates to the field of gas lubrication bearing technology, specifically to a hydrodynamic gas foil bearing with discontinuous gas film, and more particularly to a high-stability hydrodynamic gas foil bearing with discontinuous gas film. Background Technology

[0002] The working principle of hydrodynamic gas foil bearings is to utilize the hydrodynamic effect generated when the rotor rotates at high speed to form an extremely thin gas lubricating film between the top foil and the rotor, thereby supporting the rotor to levitate and rotate. It uses ambient gas as a lubricant and does not require external gas supply. It has the advantages of high speed, low friction power consumption, high temperature resistance, and strong adaptability, and is widely used in high-speed rotating machinery.

[0003] However, due to the compressibility of gas and the low damping of the foil structure itself, hydrodynamic gas foil bearings are prone to gas film eddy or even gas film instability when running at high speeds. These instabilities can significantly increase the vibration amplitude of the rotor, and in severe cases, cause the bearing and rotor to rub against each other, becoming an important technical bottleneck that limits the development of hydrodynamic gas foil bearings to higher speeds.

[0004] To improve the stability of hydrodynamic gas foil bearings, existing technologies include using micro-holes in the bearing housing to introduce external high-pressure gas to increase gas film damping. However, this increases the complexity of the system and requires high cleanliness of the external gas source. Another method is to optimize the stiffness of the elastic support structure to improve the stability of bearing operation, but its effect on suppressing gas film eddy at high speeds is limited and the design is complex.

[0005] To address the aforementioned issues, a highly stable hydrodynamic gas foil bearing is required. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the purpose of this invention is to provide a hydrodynamic gas foil bearing with discontinuous gas film.

[0007] A gas film discontinuous hydrodynamic gas foil bearing according to the present invention includes: a bearing housing, an elastic support foil, and a top foil; An elastic support foil and a top foil are installed on the inner side of the bearing housing, and the elastic support foil is located between the bearing housing and the top foil; The top foil has ventilation holes.

[0008] Preferably, a straight groove is provided on the inner wall of the bearing housing, and the elastic support foil is installed on the bearing housing through the straight groove.

[0009] Preferably, a dovetail groove is provided on the inner wall of the bearing housing, and the two ends of the top foil are installed on both sides of the dovetail groove.

[0010] Preferably, the bearing housing is provided with an inner hole for installing the elastic support foil and the top foil.

[0011] Preferably, the elastic support foil is composed of a plurality of corrugated foils arranged in a circumferential direction.

[0012] Preferably, a wedge-shaped gap is provided between the top foil and the rotor.

[0013] Preferably, the top foil is provided with multiple ventilation strips along the circumferential direction, and the ventilation strips are composed of multiple ventilation holes.

[0014] Preferably, the top foil has one or more asymmetrical vent holes.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This application divides the originally continuous air film into several independent segmented air films by opening vent holes on the top foil, thereby breaking the continuity of the air film in the circumferential direction, effectively suppressing air film eddy and air film instability, and significantly improving the operating stability of the bearing at high speed.

[0016] 2. This application does not require changes to the existing bearing housing, elastic support foil form, and bearing assembly process. It only requires adding an opening process to the top foil, which makes minimal changes to the bearing structure.

[0017] 3. This application does not require external gas supply and relies entirely on the bearing's own structure and ambient gas to improve stability, thus avoiding a complex external gas supply system. Attached Figure Description

[0018] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of a hydrodynamic gas foil bearing; Figure 2 This is an exploded view of a hydrodynamic gas foil bearing. Figure 3 This is a schematic diagram of the top foil structure; Figure 4 This is a circumferential unfolded view of the top foil. Figure 5 This is a schematic diagram of an elastic support foil structure.

[0019] As shown in the figure: Detailed Implementation

[0020] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0021] Example 1 like Figures 1-2 As shown, this embodiment includes: a bearing housing 1, an elastic support foil 2, and a top foil 3; the elastic support foil 2 and the top foil 3 are installed on the inner side of the bearing housing 1, with the elastic support foil 2 located between the bearing housing 1 and the top foil 3, and the top foil 3 fitted onto the inner side of the elastic support foil 2. A wedge-shaped gap is provided between the top foil 3 and the rotor, and the inner surface of the top foil 3 mates with the rotor to form an air film support surface. Specifically, the bearing housing 1 is provided with an inner hole for installing the elastic support foil 2 and the top foil 3, and the inner wall of the bearing housing 1 is provided with a straight groove 5 and a dovetail groove 6. The elastic support foil 2 is installed on the bearing housing 1 through the straight groove 5, and the two ends of the top foil 3 are inserted into the two sides of the dovetail groove 6.

[0022] like Figures 3-4 As shown, the top foil 3 has multiple ventilation bands along its circumference, each consisting of multiple ventilation holes 4, causing the dynamic pressure air film formed between the top foil 3 and the rotor to be discontinuously segmented along the circumference. The ventilation holes 4 penetrate the top foil 3, enabling communication between its inner and outer surfaces. In one embodiment, the top foil 3 has one or more asymmetrical ventilation holes 4. In another embodiment, the ventilation holes 4 are arranged at equal or unequal intervals along the axial direction, with a diameter of 0.1-3 mm and an axial hole spacing of 1 / 10-1 / 3 of the bearing length.

[0023] like Figure 5 As shown, the elastic support foil 2 is composed of multiple corrugated foils arranged along the circumferential direction.

[0024] Example 2 Example 2 is a preferred example of Example 1.

[0025] like Figures 1-5 As shown, this embodiment includes: a bearing seat 1, an elastic support foil 2, and a top foil 3. The bearing seat 1 has an inner hole for mounting the elastic support foil 2 and the top foil 3, which is usually round. The bearing seat 1 is also provided with a straight groove 5 for mounting the elastic support foil 2 and a dovetail groove 6 for mounting the top foil 3.

[0026] The elastic support foil 2 is installed on the inner wall of the bearing seat 1. In this embodiment, the elastic support foil 2 is preferably a corrugated foil, which is composed of multiple corrugated foils arranged in the circumferential direction, providing support stiffness and structural damping for the top foil 3.

[0027] The top foil 3 is attached to the inner side of the elastic support foil 2, and its inner surface cooperates with the rotor to form an air film support surface. Several ventilation holes 4 are opened along the axial direction on the top foil 3, and the ventilation holes 4 penetrate the top foil 3, so that the inner surface and outer surface of the top foil 3 are connected.

[0028] Specifically, in this embodiment, when the bearing is in operation, the rotor rotates at high speed. Due to the dynamic pressure effect, ambient gas is drawn into the wedge-shaped gap between the top foil 3 and the rotor, forming a lubricating gas film with a certain pressure. Due to the presence of the vent holes 4, when the high-pressure gas in the gas film flows through the vent holes 4, it will escape from the top foil 3 to the elastic support foil 2 through the vent holes 4. Due to the presence of the vent holes 4, the original overall gas film along the circumference of the bearing is divided into several relatively independent and unconnected segmented gas film units by several vent holes 4 arranged axially. This discontinuous structure interrupts the overall airflow of the gas film in the circumferential direction, thereby effectively suppressing gas film eddy and instability caused by the compressibility of the gas. To adapt to different load directions and vortex modes, the vent 4 can be arranged only at specific axial and radial positions of the top foil 3, and only one or more asymmetrically distributed vents can be opened at these positions. By relieving pressure on the air film through the asymmetrically arranged vents, anisotropy of the air film stiffness can be created, further suppressing the vortex of the air film in a specific direction.

[0029] To further optimize performance, as a preferred option, the vent holes 4 are evenly or unevenly distributed along the circumference of the top foil 3. That is, multiple vent holes 4 can be set on the same cross section of the top foil 3 to form a ventilation band. Multiple such ventilation bands are set along the circumferential direction, thereby dividing the air film into multiple parts.

[0030] Example 3 like Figures 1-5 As shown, this embodiment includes: a bearing housing 1, an elastic support foil 2, and a top foil 3. The top foil 3 is fixed to the bearing housing 1 by a dovetail groove or a straight groove, and the elastic support foil 2 is installed on the bearing housing by a straight groove or welding. The top foil 3 has several vent holes 4 along its axial direction, which penetrate the top foil 3, causing the dynamic pressure air film formed between the top foil 3 and the rotor to be discontinuously segmented along the circumferential direction. This suppresses air film vortexing and improves the bearing's operational stability. The vent holes 4 are not connected to an external air source; they disconnect the air film only through the dynamic pressure effect. The vent holes 4 are arranged at equal or unequal intervals along the axial direction, with a diameter of 0.1-3 mm, and the axial hole spacing is 1 / 10-1 / 3 of the bearing length.

[0031] The elastic support foil 2 is cylindrical in shape. Along the radial direction of the bearing seat 1, the top foil 3, the elastic support foil 2, and the bearing seat 1 are sequentially arranged from the inside to the outside. The top foil 3 and the elastic support foil 2 are respectively connected to the bearing seat 1. The outer surface of the top foil 3 abuts against the inner surface of the elastic support foil 2, and the outer surface of the elastic support foil 2 abuts against the inner surface of the bearing seat 1.

[0032] In one embodiment, the vent holes 4 are arranged in a single row or multiple rows axially. The cross-sectional shape of the vent holes 4 is one or more combinations of circles, ellipses, trapezoids, and strips.

[0033] In one embodiment, the top foil 3 is an integral flat foil or a segmented flat foil, and the materials of the top foil 3 and the elastic support foil 2 are at least one of stainless steel, nickel-based alloy and composite material, with a thickness of 0.05-2 mm.

[0034] In one embodiment, the elastic support foil 2 is one of corrugated foil, bubble foil, wire mesh, or cantilever foil.

[0035] In one embodiment, the surface of the top foil 3 is coated with a wear-resistant coating, the wear-resistant coating material being at least one of tungsten disulfide, molybdenum disulfide, and Teflon.

[0036] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A discontinuous gas film hydrodynamic foil bearing, characterized in that, include: Bearing housing (1), elastic support foil (2) and top foil (3); The bearing housing (1) is equipped with an elastic support foil (2) and a top foil (3) on its inner side, with the elastic support foil (2) located between the bearing housing (1) and the top foil (3); Ventilation holes (4) are provided on the top foil (3).

2. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: A straight groove (5) is provided on the inner wall of the bearing seat (1), and the elastic support foil (2) is installed on the bearing seat (1) through the straight groove (5).

3. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: The inner wall of the bearing seat (1) is provided with a dovetail groove (6), and the two ends of the top foil (3) are installed on both sides of the dovetail groove (6).

4. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: The bearing housing (1) is provided with an inner hole for installing the elastic support foil (2) and the top foil (3).

5. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: The elastic support foil (2) is composed of multiple corrugated foils arranged in a circumferential direction.

6. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: A wedge-shaped gap is provided between the top foil (3) and the rotor.

7. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: The top foil (3) is provided with multiple ventilation strips along the circumferential direction, and the ventilation strips are composed of multiple ventilation holes (4).

8. The gas film discontinuous hydrodynamic gas foil bearing according to claim 1, characterized in that: One or more asymmetrical vent holes (4) are provided on the top foil (3); The vent holes (4) are arranged at equal or unequal intervals along the axial direction, with a hole diameter of 0.1-3 mm and an axial hole spacing of 1 / 10-1 / 3 of the bearing length.

9. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: The top foil (3) is an integral flat foil or a segmented flat foil, and the elastic support foil (2) is one of corrugated foil, bubble foil, metal wire mesh or cantilever foil; The materials of the top foil (3) and the elastic support foil (2) include stainless steel, nickel-based alloys and composite materials, with a thickness of 0.05-2 mm; The top foil (3) is coated with a wear-resistant coating, the wear-resistant coating material including tungsten disulfide, molybdenum disulfide and Teflon.

10. The discontinuous gas film hydrodynamic foil bearing according to claim 1, characterized in that: The cross-sectional shape of the vent (4) includes one or more combinations of circles, ellipses, trapezoids and stripes.

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