Integral crimped multi-leaf lapped foil gas dynamic pressure bearing

Abstract

This invention discloses an integrally rolled multi-leaf overlapping foil gas dynamic bearing, comprising a bearing sleeve (4) and a bearing elastic component disposed within the bearing sleeve (4). The bearing elastic component comprises a bottom foil (3) and multiple elastic foils (2); the bottom foil (3) is fixed to the inner surface of the bearing sleeve (4); the multiple elastic foils (2) are distributed circumferentially on the radial inner side of the bottom foil (3), and each elastic foil (2) has a fixed end and a free end. The fixed end is fixed to the inner surface of the bottom foil (3), and the free end overlaps on another circumferentially adjacent elastic foil (2). The bottom foil (3) and the multiple elastic foils (2) are pre-connected in a flat state to form an integral whole, and are integrally rolled and placed within the bearing sleeve (4). This invention reduces the complex three-dimensional assembly to a two-dimensional planar connection, completely solving the defects of cumbersome processing and assembly and high cost of traditional multi-leaf bearings. At the same time, the overlapping structure provides large-area surface contact dry friction damping and multi-wedge flow field, significantly improving the high-speed stability and low-speed take-off capability of the bearing.

Description

Technical Field

[0001] This invention relates to the field of hydrodynamic lubrication and high-speed rotating machinery support technology, and more specifically, to a foil gas hydrodynamic bearing, particularly an integrally rolled multi-leaf overlapping foil gas hydrodynamic bearing. Background Technology

[0002] Foil gas hydrodynamic bearings are advanced bearings that use gas as the lubricating medium and achieve non-contact rotor support based on the hydrodynamic effect. Compared with traditional oil-lubricated bearings, they have significant advantages such as low frictional power consumption, no pollution, maintenance-free operation, and adaptability to ultra-high speed and extreme temperature environments. They have broad application prospects in high-speed rotating machinery such as aerospace, fuel cell air compressors, and micro gas turbines.

[0003] Currently, mainstream foil gas bearings are mainly divided into two categories: multi-blade and corrugated foil. Firstly, traditional multi-blade foil bearings typically consist of multiple independent elastic blades. One end of each blade needs to be inserted into a densely packed slot in the inner wall of the bearing sleeve, or fixed individually with pins, with adjacent blades overlapping. While this structure can form multiple converging wedge-shaped gas films, which is beneficial for rotor takeoff at low speeds, it presents significant manufacturing and assembly challenges. Firstly, machining high-precision, densely packed slots in the bearing sleeve's inner bore is costly; secondly, assembling dozens of loose blades individually is extremely cumbersome, highly dependent on manual labor, and difficult to guarantee consistency in mass production; furthermore, under high-speed airflow impact, the independently fixed blades are prone to loosening or warping, resulting in insufficient overall structural reliability. Secondly, the widely used corrugated foil gas bearing uses a single stamped corrugated metal foil as the bottom support. However, the traditional corrugated foil only has "line contact" with the top foil and bearing sleeve, resulting in a small dry friction damping area under pressure deformation, limiting its ability to dissipate rotor vibration energy. Furthermore, a smooth top foil supported by a single corrugated foil can usually only form a continuous single wedge-shaped air film, and its low-speed buoyancy and high-speed stability are not as good as those of a multi-bladed foil bearing.

[0004] Therefore, there is an urgent need in this field for a new type of foil gas dynamic bearing that can completely solve the defects of traditional multi-leaf bearings, such as extremely difficult assembly and high manufacturing cost, and can also provide large-area dry friction damping and excellent gas film buoyancy characteristics. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides an integrally rolled multi-leaf overlapping foil gas dynamic bearing. It aims to solve the problems of difficult processing and assembly and high manufacturing cost of traditional multi-leaf foil bearings through pre-assembly and integral rolling processes, while overcoming the technical defects of insufficient dry friction damping and weak low-speed lifting capability of traditional corrugated foil bearings.

[0006] To achieve the above-mentioned technical objectives, the present invention provides the following technical solutions: This invention provides an integrally rolled multi-leaf overlapping foil gas hydrodynamic bearing, comprising a bearing sleeve and a bearing elastic assembly disposed within the bearing sleeve. The bearing elastic assembly includes a base foil and multiple elastic foils; the base foil is fixed to the inner surface of the bearing sleeve. The multiple elastic foils are distributed circumferentially on the radially inner side of the base foil, and all elastic foils face the same direction. Each elastic foil has a fixed end and a free end; the fixed end is fixed to the inner surface of the base foil, and the free end overlaps with another circumferentially adjacent elastic foil. The base foil and the multiple elastic foils form a pre-connected integral and are integrally rolled and placed within the bearing sleeve.

[0007] Furthermore, in another embodiment, the bearing elastic assembly further includes a top foil disposed radially inside a plurality of elastic foils. One end of the top foil is fixed to the bottom foil or bearing sleeve, and the other end is a free end; the plurality of elastic foils act as elastic supports, supported on the outer surface of the top foil. The elastic foils are configured such that, upon compression deformation, the free ends of the elastic foils can generate relative sliding on the surfaces of adjacent elastic foils they overlap, thereby providing dry friction damping.

[0008] Furthermore, the overlapping elastic foils form an internal hole structure with a multi-segmented cross-section in the circumferential direction. In one embodiment, the multiple elastic foils face the bearing rotor directly, and a stepped structure is formed between adjacent elastic foils to jointly surround and form multiple converging wedge-shaped air film spaces with the outer wall of the rotor.

[0009] Furthermore, one end of the bottom foil has a bottom foil fixing end, which is fixed together with the fixing end of one of the elastic foils to the inner surface of the bearing sleeve. Preferably, the fixing end of the elastic foil is fixed to the upper surface of the bottom foil when it is in a flat state by spot welding or laser welding, and then the elastic foil and the bottom foil are rolled together into a cylindrical shape.

[0010] Furthermore, the elastic foil is divided into at least two groups along the axial direction of the bearing sleeve, and the adjacent groups of elastic foil are staggered from each other by a predetermined angle in the circumferential direction.

[0011] This invention eliminates the cumbersome process of precision slotting and piece-by-piece insertion required in traditional multi-leaf bearings. Instead, elastic foil sheets are pre-welded to a flat base foil in a flat state to form an integrated assembly, which is then rolled into the bearing sleeve as a whole. This method reduces complex three-dimensional assembly to simple two-dimensional planar welding, significantly reducing processing difficulty and manual assembly costs, and substantially improving the yield and consistency of mass production.

[0012] When the overlapping structure of this invention serves as an elastic support for the top foil, under the action of rotor film pressure, the free ends of the elastic foil will experience slight sliding on the surfaces of adjacent foils. Compared to the "line contact" friction of traditional corrugated foils, this invention provides significantly greater "surface contact" dry friction damping. This powerful damping dissipation capability can effectively suppress the self-excited vibration of high-speed rotors and broaden the high-speed stable operating range of the bearing.

[0013] When the overlapping structure of this invention is used directly as the working surface, multiple elastic foils form a multi-segment linear inner hole, naturally creating multiple converging stepped wedge-shaped air film spaces. This multi-wedge flow field distribution can generate greater hydrodynamic lift than a traditional single circular arc top foil during the low-speed start-up phase of the rotor, effectively reducing the bearing's take-off speed and decreasing dry friction wear during the start-up and shutdown phases.

[0014] By dividing the elastic foil into multiple groups along the axial direction and arranging them in an alternating manner along the circumference, this invention breaks through the stiffness barrier of a single axial distribution, effectively smooths the circumferential stiffness fluctuation of the bearing inner hole, avoids local stress concentration, and enhances the rotor's resistance to eccentric loads under complex load disturbances. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 An exploded view of the bearing provided for this invention.

[0017] Figure 2 This is a partially enlarged view of the bearing provided by the present invention.

[0018] Figure 3 An exploded view of bearing design 2 provided by the present invention.

[0019] Figure 4 This is a partially enlarged view of bearing design two provided by the present invention.

[0020] The labels for the various figures in the diagram are: 1-top foil, 2-elastic foil, 3-bottom foil, 4-bearing sleeve. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "top," "bottom," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention 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, and therefore should not be construed as a limitation of this invention.

[0023] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of the invention, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0024] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] This invention provides an integrally rolled multi-leaf overlapping foil gas hydrodynamic bearing. Its core innovation lies in pre-connecting the base foil and elastic foil in a planar state, followed by integral rolling, thus replacing the complex component assembly process of traditional multi-leaf bearings. Depending on the specific application conditions, this invention provides two preferred embodiments.

[0027] Example 1: Overlapping gas hydrodynamic bearing with top foil, refer to Figure 1 and Figure 2As shown, the bearing includes a bearing sleeve (4) and a bearing elastic assembly installed in its inner bore. The bearing elastic assembly includes, from the outside to the inside, a bottom foil (3), multiple elastic foils (2) and a top foil (1).

[0028] The bottom foil (3) is attached and fixed to the inner surface of the bearing sleeve (4). Multiple elastic foils (2) are arranged closely in the radial direction on the inner side of the bottom foil (3) in the circumferential direction, and the tilting orientation of all elastic foils (2) is consistent.

[0029] Each elastic foil (2) has a fixed end and a free end. The fixed end is fixed to the inner surface of the bottom foil (3) by spot welding, laser welding or other methods; the free end extends circumferentially and overlaps the back (or outer surface) of the next adjacent elastic foil (2) to form a continuous overlapping structure similar to fish scales.

[0030] The top foil (1) is located at the innermost radial side of all the elastic foils (2), with one end (the fixed end of the top foil) fixed together with the end of the bottom foil (3) on the bearing sleeve (4), and the other end free. At this time, multiple overlapping elastic foils (2) serve as the bottom support members, jointly supporting the outer surface of the top foil (1).

[0031] Under high-speed, heavy-load conditions, the rotor transmits the air film pressure to the top foil (1), which in turn presses down on the elastic foil (2). Since the elastic foil (2) has an overlapping structure, when deformed under pressure, the free ends of each elastic foil (2) will slip relative to each other on the surfaces of their overlapping adjacent foils. This large-area "surface contact" slip produces significant dry friction damping, which can absorb and dissipate the vibration energy of the rotor extremely effectively, avoiding low-frequency resonance caused by insufficient damping in traditional corrugated foil bearings, and greatly improving the high-speed stability of the rotor system.

[0032] Example 2: Multi-wedge gas hydrodynamic bearing without top foil, refer to Figure 3 and Figure 4 As shown, this embodiment provides another, more compact implementation. This scheme omits the top foil (1), and the bearing elastic assembly consists only of the bottom foil (3) and multiple elastic foils (2).

[0033] The fixed end of the elastic foil (2) is also welded to the bottom foil (3), and the free ends overlap each other. However, in this embodiment, the elastic foil (2) faces the rotor directly as the gas film working surface.

[0034] In the preferred manufacturing state, the elastic foil (2) is initially a flat foil. When it is rolled up and placed into the bearing sleeve (4) along with the bottom foil (3), due to the flatness and rigidity of the foil itself and the overlapping relationship, the multiple overlapping elastic foils (2) form an inner hole structure with a cross-section of "polyline" (similar to a polygon) in the circumferential direction.

[0035] A certain step height is formed at the overlap between adjacent elastic foils (2). When the rotor rotates in the inner hole composed of these polylines, an independent and converging wedge-shaped air film space is formed between the inner surface of each elastic foil (2) and the outer wall of the rotor.

[0036] This "multi-wedge" flow field distribution, compared to the single wedge shape of the traditional smooth circular arc top foil, can generate huge hydrodynamic lift at extremely low speeds, allowing the rotor to quickly escape the dry friction state and greatly reducing wear on the bearing coating during start-up and shutdown. At the same time, the micro-slippage at the foil overlap under pressure can still provide the necessary frictional damping.

[0037] The core technological advantage of this invention lies in its complete overturning of the traditional assembly method of multi-leaf bearings.

[0038] During assembly, the bottom foil (3) is first laid flat on the tooling platform. Multiple elastic foils (2) that are initially flat are arranged at equal intervals, and their fixed ends are sequentially welded to the flat bottom foil (3) using automated welding equipment. At this time, the entire component is in a two-dimensional plane state, which makes the processing extremely simple and the positioning accuracy extremely high.

[0039] After welding, the bottom foil (3) and the elastic foil (2) on it are rolled into a cylindrical shape and pushed into the bearing sleeve (4) as a whole. The end opening of the bottom foil (3) is then fixed to complete the assembly. This process eliminates the extremely high cost of precision slotting on the inner wall of the bearing sleeve, eliminates the tediousness and inconsistency of assembling disassembled parts, and realizes low-cost, high-reliability mass production of multi-leaf foil bearings.

[0040] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention, such as changing the specific overlap ratio, size, material, or fixing method of the elastic foil, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A one-piece coiled multi-leaf overlapping foil gas dynamic bearing, characterized in that, include: Bearing sleeve (4); and bearing elastic assembly disposed within the bearing sleeve (4); The bearing elastic component includes a bottom foil (3) and a plurality of elastic foil pieces (2); the bottom foil (3) is fixed to the inner surface of the bearing sleeve (4); The plurality of elastic foils (2) are distributed circumferentially on the radial inner side of the bottom foil (3), and the orientation of each elastic foil (2) is the same; Each of the elastic foils (2) has a fixed end and a free end, the fixed end being fixed to the inner surface of the bottom foil (3), and the free end being overlapped on another circumferentially adjacent elastic foil (2); The bottom foil (3) and the plurality of elastic foils (2) form a pre-connected whole and are rolled up and placed inside the bearing sleeve (4).

2. The integrally coiled multi-leaf overlapping foil gas dynamic bearing according to claim 1, characterized in that: The multiple elastic foils (2) that overlap each other form an inner hole structure with a multi-segment line shape in the circumferential direction.

3. The integrally coiled multi-leaf overlapping foil gas dynamic bearing according to claim 2, characterized in that: The multiple elastic foils (2) face the rotor directly, and a stepped structure is formed between adjacent elastic foils (2) to form multiple converging wedge-shaped air film spaces together with the outer surface of the rotor.

4. The integrally coiled multi-leaf overlapping foil gas dynamic bearing according to claim 1, characterized in that: The bearing elastic assembly further includes a top foil (1), which is disposed on the radial inner side of the plurality of elastic foils (2); One end of the top foil (1) is fixed to the bottom foil (3) or the bearing sleeve (4), and the other end is a free end; the plurality of elastic foils (2) serve as elastic support members and are supported on the outer surface of the top foil (1).

5. The integrally coiled multi-leaf overlapping foil gas dynamic bearing according to claim 1, characterized in that: The elastic foil (2) is configured such that, when deformed under pressure, the free end of the elastic foil (2) can generate relative sliding on the surfaces of adjacent elastic foils (2) to which it overlaps, so as to provide dry friction damping.

6. The integrally coiled multi-leaf overlapping foil gas dynamic bearing according to claim 1, characterized in that: One end of the bottom foil (3) has a bottom foil fixing end, which is fixed together with the fixing end of one of the elastic foils (2) to the inner surface of the bearing sleeve (4).

7. The integrally coiled multi-leaf overlapping foil gas dynamic bearing according to claim 1, characterized in that: The fixed end is fixed to the upper surface of the bottom foil (3) by welding, and together with the bottom foil (3) forms an integral rolled cylindrical structure.

8. The integrally coiled multi-leaf overlapping foil gas dynamic bearing according to claim 1, characterized in that: The elastic foil (2) is divided into at least two groups along the axial direction of the bearing sleeve (4), and the adjacent groups of elastic foil (2) are staggered by a preset angle in the circumferential direction.

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