A new type of dual-rotation foil gas dynamic pressure bearing

Abstract

The present application relates to the technical field of gas bearings, and provides a novel dual-rotation foil gas dynamic pressure bearing, comprising: a bearing sleeve, a foil, a top foil, a magnet, a retaining ring and a screw; the foil is connected by a plurality of "ZS"-shaped structures, and the "ZS"-shaped structures at the head and tail ends of the foil are nested and connected with each other. The "ZS"-shaped structures of the foil can expand and deform outwards after being stressed, and can automatically shrink after unloading, and have a certain support stiffness, and the sliding friction effect between the foil and the bearing sleeve provides damping for the bearing; the top foil is connected by a "triangular" support at the head and tail ends and a circular support. The arc surface is composed of a "triangle" support of the top foil nested in the "ZS" structure of the foil. After the foil is deformed, the "triangle" support pulls the arc surface of the top foil, and the top foil will slightly detach from the foil, changing the thickness and shape of the air film, which is beneficial to reducing the subsynchronous vibration of the rotor; the magnet is installed in the groove of the bearing sleeve, and the magnetic force acts on the foil to reduce the movement of the foil. When the foil moves, it cuts the magnetic flux lines generated by the magnet, generates eddy currents to consume energy, and provides damping for the bearing; the retaining ring is fixed to the bearing sleeve by screws to limit the axial movement of the foil and the top foil. This application has good stiffness and damping characteristics, allows the rotor to rotate in both directions, is simple in structure, does not require welding, and is easy to disassemble.

Description

Technical Field

[0001] The invention relates to the technical field of gas dynamic pressure bearings, and in particular to a novel double-rotation foil gas dynamic pressure bearing. Background Art

[0002] Gas dynamic bearings use high-pressure air film to support the rotor without contact. They have the advantages of high speed, stability, reliability, oil-free lubrication, and high efficiency. They are widely used in high-speed, light-load rotating equipment such as high-speed air cycle machines, fuel cell air compressors, air chillers, micro gas turbines, and micro turbojet engines.

[0003] One end of the top foil of the traditional foil gas dynamic pressure bearing is fixed to the bearing sleeve, and the other end is freely placed on the foil. The fixed end of the top foil limits the circumferential and radial movement of the top foil, and the free end allows the circumferential and radial displacement of the top foil. The direction of rotation of the rotor points from the free end of the top foil to the fixed end of the top foil. The rotor with a certain mass divides the air film space surrounded by the top foil surface and the rotor surface into a convergence domain and a diffusion domain, forming a high-pressure area and a low-pressure area. The high-pressure air film presses the free end top foil toward the foil, while the low-pressure area attracts the top foil to move toward the rotor. The fixed end of the top foil limits the top foil from fitting the rotor. Therefore, the traditional foil gas dynamic pressure bearing only supports one-way rotation of the rotor and cannot rotate in the opposite direction, otherwise the top foil will fit the rotor and be worn and burned. In addition, the boundary speed of the air film, the rotor, and the top foil is equal to the speed of the rotor and the top foil surface. The velocity gradient in the thickness direction of the air film produces cross stiffness to do negative work on the system. When the negative work is greater than the energy consumption of the bearing damping, a subsynchronous resonance of the rotor of about 0.5 times the speed will be generated, destroying the stability of the system. Summary of the invention

[0004] In view of the above technical deficiencies, the present application provides a novel dual-rotation foil gas dynamic pressure bearing, which embeds the end of the top foil in the foil, constrains the movement characteristics of part of the top foil, realizes the bidirectional rotation of the rotor and weakens the continuity of the air film, and introduces the eddy current energy dissipation characteristics into the bearing, increases the foil energy dissipation, and solves the technical problem of poor stability of the existing gas dynamic pressure bearing system. The many technical effects that can be produced by the preferred technical solution among the many technical solutions provided by the present invention are described below.

[0005] In order to achieve the above technical objectives, the present invention provides the following technical solutions:

[0006] The invention provides a novel dual-rotation foil gas dynamic pressure bearing, comprising a bearing sleeve, a foil, a top foil, a magnet, a retaining ring and a screw; the foil is formed by connecting a plurality of "ZS"-shaped structures, the "ZS"-shaped structures at the head and tail ends of the foil are nested and connected with each other, the "ZS"-shaped structures of the foil can expand and deform outward after being stressed, and can automatically recover after unloading, and have a certain support stiffness, and the sliding friction between the foil and the bearing sleeve provides damping for the bearing; the top foil is composed of a "triangular" support and an arc-shaped surface at the head and tail ends, The "triangle" support of the top foil is nested in the "ZS" shaped structure of the foil. After the foil is deformed, the "ZS" shaped structure pulls the top foil, and the top foil will slightly detach from the foil, changing the thickness and shape of the air film, which is beneficial to reducing the subsynchronous vibration of the rotor; the magnet is installed in the groove of the bearing sleeve, and the magnetic force acts on the foil to reduce the movement of the foil. When the foil moves, it cuts the magnetic lines of force generated by the magnet, generates eddy currents to consume energy, and provides damping force for the bearing; the retaining ring is fixed to the bearing sleeve by screws to limit the axial movement of the foil and the top foil.

[0007] The above-mentioned novel dual-rotation foil gas dynamic pressure bearing, wherein the foil is composed of a plurality of "ZS" shaped structures pressed from a metal sheet, the "ZS" shaped structures at the head and tail ends of the foil are nested and connected to each other, the foil stiffness on the circumference is the same, the side and bottom connection of the "ZS" shaped structure is an arc transition, there is a notch at the top corner of the "ZS" shaped structure, the foil expands and deforms outwards after being subjected to force, the two side edges of the "ZS" shaped structure move closer to the middle of the notch, pulling the adjacent "ZS" shaped structure to deform, maintaining the elastic deformation of the foil, having a certain support stiffness, the "ZS" shaped structure can automatically recover after unloading, the adjacent "ZS" shaped structures recover, and when the mutually linked "ZS" shaped structures are deformed, relative sliding occurs between the foil and the bearing sleeve, providing friction damping for the bearing.

[0008] In the above-mentioned novel dual-rotation foil gas dynamic pressure bearing, the size of the gap of the "ZS"-shaped structure in the foil affects the circumferential distribution of the foil stiffness, and the size of the gap is adjusted according to actual requirements.

[0009] The above-mentioned novel dual-rotation foil gas dynamic pressure bearing, wherein the top foil is pressed from a metal sheet, and consists of a "triangular" support and an arc-shaped surface. The "triangular" support of the top foil is similar to the "ZS"-shaped structure of the foil, and its size is slightly smaller than the "ZS"-shaped structure. The top foil "triangular" support is nested in the "ZS"-shaped structure of the foil.

[0010] In the above-mentioned novel dual-rotational foil gas hydrodynamic bearing, there are multiple top foils in the circumferential direction of the bearing, which are nested in the "ZS" shaped structure of the foil through the "triangle" support of the top foil. After the foil is deformed, the top foil is pulled by the "ZS" shaped structure, and the top foil will slightly detach from the foil, changing the thickness and shape of the air film. The multiple top foils cut off the continuity of the air film and the deformed top foil forms a preload characteristic, which is beneficial to reducing the subsynchronous vibration of the rotor.

[0011] The above-mentioned new type of dual-rotation foil gas dynamic pressure bearing, wherein the magnet is fixed in the groove in the bearing sleeve, and the number of the magnets distributed along the axial and circumferential directions of the bearing is determined according to actual needs; the magnet generates magnetic force acting on the foil, which can reduce the movement of the foil and realize the rotor take-off; the magnet generates magnetic flux lines, and the moving foil cuts the magnetic flux lines, generating eddy currents to consume the vibration energy of the foil, which is beneficial to the stability of the rotor-bearing system; the magnet is replaced by an electromagnetic conversion device composed of a coil and an iron core, and the electromagnetic conversion device of the coil and the iron core can generate magnetic flux lines to replace the magnet.

[0012] In the above-mentioned novel dual-rotation foil gas dynamic pressure bearing, the axial length of the bearing is slightly greater than the length of the foil and the top foil; the retaining ring is fixed to the bearing sleeve by the screw, limiting the axial movement of the foil and the top foil and allowing the circumferential rotation of the foil and the top foil.

[0013] In the above-mentioned novel dual-rotation foil gas hydrodynamic bearing, the magnet is replaced by an L-shaped baffle, which is placed in the groove of the bearing sleeve to limit the circumferential movement of the foil and prevent the foil and the top foil from rotating with the rotor during the rotor take-off phase; in addition, the foil is fixed to the inner surface of the bearing sleeve by welding.

[0014] The above-mentioned novel dual-rotation foil gas dynamic pressure bearing has a space in the middle of the "ZS"-shaped structure of the foil, which is filled with rubber damping material to increase the stiffness and damping effect of the bearing, fill the "triangular" support of the top foil, and change the axial and circumferential stiffness distribution of the bearing.

[0015] Due to the adoption of the above technology, the present invention has the following positive effects compared with the prior art:

[0016] (1) The present invention achieves the goal of embedding the end of the top foil in the foil sheet. The loaded foil sheet pulls the end of the top foil so that the arc-shaped surface of the top foil slightly separates from the foil sheet, thereby changing the thickness of the bearing air film, weakening the continuity of the overall air film, and reducing the dynamic cross stiffness of the bearing, which is beneficial to the stability of the bearing. At the same time, the foil sheet constrains the movement characteristics of a part of the two ends of the top foil, preventing the top foil from sticking to the rotor, thereby realizing bidirectional rotation of the rotor.

[0017] (2) The present invention realizes placing a magnet in the groove of the bearing sleeve, thereby increasing the friction effect between the foil and the bearing sleeve, and introducing the eddy current energy dissipation characteristics into the bearing, thereby increasing the energy dissipation of the foil and further improving the high-speed stability of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 An exploded view of a novel dual-rotation foil gas hydrodynamic bearing provided in an embodiment of the present invention.

[0020] Figure 2 A front view of the top foil of a novel dual-rotational foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0021] Figure 3 A partial enlarged view of the foil of a novel dual-rotational foil gas dynamic pressure bearing provided in an embodiment of the present invention.

[0022] Figure 4 A schematic diagram of multiple top foil bearings of a novel dual-rotation foil gas hydrodynamic bearing provided in an embodiment of the present invention.

[0023] Figure 5 An isometric view of multiple top foil bearings of a novel dual-rotation foil gas hydrodynamic bearing provided by an embodiment of the present invention.

[0024] Figure 6 A schematic diagram of the installation of the top foil and foil of a novel dual-rotational foil gas dynamic pressure bearing provided by an embodiment of the present invention.

[0025] Figure 7 A schematic diagram of a top foil of a novel dual-rotational foil gas hydrodynamic bearing provided in an embodiment of the present invention.

[0026] Figure 8 An exploded view of a bearing with an L-shaped baffle added to a novel dual-rotational foil gas hydrodynamic bearing provided in an embodiment of the present invention.

[0027] Fig. 9 An exploded view of a novel dual-rotational foil gas hydrodynamic bearing with a damping block added thereto provided in an embodiment of the present invention.

[0028] Among them, the markings of the figures in the figure are: 1-bearing sleeve, 2-foil, 3-top foil, 4-magnet, 5-retaining ring, 6-screw, 7-L-shaped baffle, 8-damping block, 21-"ZS" shaped structure, 31-top foil arc surface, 32-"triangle" support. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise specified, "several" means two or more than two; the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the term "preload" is interpreted as the uneven gap between the top foil and the rotor, which is only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] The foil gas bearing provided in the embodiment of the present application is now described.

[0032] Please refer to Figures 1 to 7 As shown, a novel dual-rotation foil gas dynamic pressure bearing is shown, which is composed of a bearing sleeve (1), a foil (2), a top foil (3), a magnet (4), a retaining ring (5) and a screw (6).

[0033] Furthermore, the foil (2) is composed of a plurality of the "ZS"-shaped structures (21) pressed from a metal sheet, the "ZS"-shaped structures (21) at the head and tail ends of the foil (2) are nested and connected to each other, one of the "ZS"-shaped structures (21) is slightly smaller, and the "ZS"-shaped structures (21) after being nested have the same rigidity as the "ZS"-shaped structures (21) at other positions on the circumference, the connection between the side and the bottom of the "ZS"-shaped structure (21) is an arc transition, and there is a notch at the top corner of the "ZS"-shaped structure (21), and the foil after being subjected to force (2) the “ZS” shaped structure (21) expands and deforms outwards, and the two sides of the “ZS” shaped structure (21) move toward the middle of the notch, pulling the adjacent “ZS” shaped structure (21) to deform, maintaining the elastic deformation of the foil (2), so that the foil (2) has a certain supporting stiffness; after unloading, the “ZS” shaped structure (21) can automatically recover, and the adjacent “ZS” shaped structures (21) recover; when the mutually linked “ZS” shaped structures (21) are deformed, relative sliding occurs between the foil (2) and the bearing sleeve (1), providing friction damping for the bearing.

[0034] Furthermore, the top foil (3) is composed of a "triangular" support (32) at the head and tail ends and an arc-shaped surface (31); the contact position between the "triangular" support (32) and the arc-shaped surface (31) adopts an arc transition; the "triangular" support (32) of the top foil (3) is nested in the "ZS"-shaped structure (21) of the foil (2); the size of the "triangular" support (32) is slightly smaller than that in the "ZS"-shaped structure (21) and is close to the "ZS"-shaped structure (21); after the foil (2) is deformed, the "triangular" support (32) of the top foil (3) is pulled by the "ZS"-shaped structure (21); the arc-shaped surface of the top foil (3) will slightly separate from the foil (2), thereby changing the thickness shape of the air film, which is beneficial to reducing the subsynchronous vibration of the rotor;

[0035] Furthermore, the magnet (4) is installed in the groove of the bearing sleeve (1), and the magnetic force acts on the foil (2), thereby increasing the friction between the foil (2) and the bearing sleeve (1), reducing the movement of the foil (2), and increasing the damping of the bearing. At the same time, when the foil (2) moves, it cuts the magnetic flux lines generated by the magnet (4), generates eddy currents to consume energy, and provides damping force for the bearing.

[0036] Furthermore, the retaining ring (5) is fixed to the bearing sleeve (1) by the screw (6) to limit the axial movement of the foil (2) and the top foil (3).

[0037] Optionally, the size of the gap in the "ZS"-shaped structure (21) in the foil (2) affects the circumferential distribution of the foil stiffness, and the size of the gap is adjusted according to actual requirements.

[0038] Optionally, the arc-shaped surface (31) can be connected to any side edge of the "triangle" support (32), ensuring that the "triangle" support (32) is similar to the "ZS" shaped structure (21) and is slightly smaller than the "ZS" shaped structure (21), and the "triangle" support (32) is nested in the "ZS" shaped structure (21).

[0039] Optionally, there are multiple top foils (3) in the circumferential direction of the bearing, which are nested in the "ZS"-shaped structure (21) through the "triangle" support (32). After the foil is deformed, the top foil (3) is pulled by the "ZS"-shaped structure (21), and the top foil (3) will slightly detach from the foil, changing the thickness and shape of the air film. The multiple top foils (3) cut off the continuity of the air film, and the deformed top foil (3) forms a preload characteristic, which is beneficial to reducing the subsynchronous vibration of the rotor.

[0040] Optionally, the magnet (4) is fixed in a groove in the bearing sleeve (1), and the number of the magnets (4) distributed along the axial and circumferential directions of the bearing is determined according to actual needs; the magnet (4) is replaced by an electromagnetic conversion device composed of a coil and an iron core, and the electromagnetic conversion device of the coil and the iron core can generate magnetic lines of flux to replace the magnet (4).

[0041] Optionally, the magnet (4) is replaced by the L-shaped baffle (7), and the L-shaped baffle (7) is placed in the groove of the bearing sleeve (1) to limit the circumferential movement of the foil (2) and prevent the foil (2) and the top foil (3) from rotating with the rotor during the rotor take-off phase; in addition, the foil (2) is fixed to the inner surface of the bearing sleeve (1) by welding.

[0042] Optionally, the axial length of the bearing is slightly greater than the length of the foil (2) and the top foil (3); the retaining ring (5) is fixed to the bearing sleeve (1) via the screw (6), limiting the axial movement of the foil (2) and the top foil (3) and allowing the circumferential rotation of the foil (2) and the top foil (3).

[0043] Optionally, a space is left in the middle of the "ZS"-shaped structure (21) of the foil (2), which is filled with a rubber-like damping material to increase the stiffness and damping effect of the bearing, and the "triangular" support (32) with a slightly smaller filling length changes the axial and circumferential stiffness distribution of the bearing.

[0044] The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, modification, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A novel dual-rotation foil gas dynamic pressure bearing, characterized in that: include: A bearing sleeve (1), a foil (2), a top foil (3), a magnet (4), a retaining ring (5) and a screw (6); the foil (2) is formed by connecting a plurality of "ZS"-shaped structures (21); the "ZS"-shaped structures (21) at the head and tail ends of the foil (2) are mutually nested and connected; the "ZS"-shaped structures (21) can expand and deform outwards after being subjected to force, and can automatically recover after being unloaded, and have a certain support stiffness; and the sliding friction between the foil (2) and the bearing sleeve (1) provides damping for the bearing; the top foil (3) is composed of a "triangular" support (32) at the head and tail ends and a circular arc surface (31); the "triangular" support (32) of the top foil (3) is nested in the foil ( 2), after the foil (2) is deformed, it pulls the top foil (3) through the "ZS" shaped structure (21), and the top foil (3) will slightly separate from the foil (2), changing the thickness and shape of the air film, which is beneficial to reducing the sub-synchronous vibration of the rotor; the magnet (4) is installed in the groove of the bearing sleeve (1), and the magnetic force acts on the foil (2) to reduce the movement of the foil (2). When the foil (2) moves, it cuts the magnetic flux lines generated by the magnet, generates eddy currents to consume energy, and provides damping force for the bearing; the retaining ring (5) is fixed to the bearing sleeve (1) by the screw (6), limiting the axial movement of the foil (2) and the top foil (3).

2. The novel dual-rotation foil gas dynamic pressure bearing according to claim 1 is characterized in that: The foil (2) is composed of a plurality of "ZS"-shaped structures (21) pressed from a metal sheet. The "ZS"-shaped structures (21) at the head and tail ends of the foil (2) are mutually nested and connected. The foil stiffness on the circumference is the same. The connection between the side and bottom of the "ZS"-shaped structure (21) is an arc transition. There is a notch at the top corner of the "ZS"-shaped structure (21). The size of the notch of the "ZS"-shaped structure (21) affects the circumferential distribution of the foil stiffness. The size of the notch is adjusted according to actual requirements. After the foil is subjected to force, (2) the "ZS" shaped structure (21) expands and deforms outwards, and the two sides of the "ZS" shaped structure (21) move toward the middle of the notch, pulling the adjacent "ZS" shaped structure (21) to deform, maintaining the elastic deformation of the foil (2), and having a certain supporting stiffness. After unloading, the "ZS" shaped structure (21) can automatically recover, and the adjacent "ZS" shaped structures (21) recover. When the mutually linked "ZS" shaped structures (21) are deformed, relative sliding occurs between the foil (2) and the bearing sleeve (1), providing friction damping for the bearing.

3. The novel dual-rotation foil gas dynamic pressure bearing according to claim 1 is characterized in that: The top foil (3) is formed by pressing a metal sheet, and is composed of the "triangular" support (32) and the arc-shaped surface (31); the "triangular" support (32) of the top foil (3) is similar to the "ZS"-shaped structure (21), and is slightly smaller in size than the "ZS"-shaped structure (21); and the "triangular" support (32) is nested in the "ZS"-shaped structure (21).

4. The novel dual-rotation foil gas dynamic pressure bearing according to claim 1 is characterized in that: The top foil (3) is multiple in the circumferential direction of the bearing, and is nested in the "ZS"-shaped structure (21) through the "triangle" support (32). After the foil is deformed, the top foil (3) is pulled by the "ZS"-shaped structure (21), and the top foil (3) will slightly separate from the foil, changing the thickness and shape of the air film. The multiple top foils (3) cut off the continuity of the air film, and the deformed top foil (3) forms a preload characteristic, which is beneficial to reducing the subsynchronous vibration of the rotor.

5. The novel dual-rotation foil gas dynamic pressure bearing according to claim 1 is characterized in that: The axial length of the bearing is slightly greater than the length of the foil (2) and the top foil (3); the retaining ring (5) is fixed to the bearing sleeve (1) via the screw (6), limiting the axial movement of the foil (2) and the top foil (3) and allowing the circumferential rotation of the foil (2) and the top foil (3).

6. The novel dual-rotation foil gas dynamic pressure bearing according to claim 1 is characterized in that: The magnet (4) is replaced by an L-shaped baffle (7), which is placed in the groove of the bearing sleeve (1) to limit the circumferential movement of the foil (2) and prevent the foil (2) and the top foil (3) from rotating with the rotor during the rotor take-off phase; in addition, the foil (2) is fixed to the inner surface of the bearing sleeve (1) by welding.

7. The novel dual-rotation foil gas dynamic pressure bearing according to claim 1 is characterized in that: A space is left in the middle of the "ZS"-shaped structure (21) of the foil (2), which is filled with a rubber-type damping material to increase the stiffness and damping effect of the bearing, fill the "triangular" support (32), and change the axial and circumferential stiffness distribution of the bearing.

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