CN118293147A - Axial clearance-variable type gas dynamic pressure bearing - Google Patents

Abstract

The invention relates to the technical field of gas dynamic pressure bearings, and provides an axial gap-variable gas dynamic pressure bearing, which comprises: top foil, bearing support structure, bearing housing; the bearing supporting structure is formed by circumferentially distributing a plurality of X-shaped beams and sequentially overlapping the X-shaped beams, the X-shaped beams are formed by intersecting two straight beams, a certain included angle is formed between each straight beam and the axis direction of a bearing, the included angle enables the distance between each straight beam and a rotor shaft to be reduced and increased along the direction of the straight beam, the part between the bearing supporting structures is firstly contacted with a top foil, the end part of each bearing supporting structure is not contacted with the top foil, the top foil is provided with an air film gap with initial axial change, one end of each X-shaped beam is fixed in a groove of a bearing sleeve, the other end of each X-shaped beam is free, and the next X-shaped beam supports the previous X-shaped beam; the top foil is fixed on the bearing sleeve, the other end of the top foil is freely lapped on the bearing supporting structure, the direction from the free end to the fixed end of the top foil is the same as the direction from the free end to the fixed end of the X-shaped beam, the deformation of the top foil between the adjacent X-shaped beams is smaller than that of the top foil between the two straight beams, the concave deformation with a certain included angle with the axis of the rotor is formed, the effect similar to that of a herringbone notch bearing is achieved, and the technical problems of bearing end abrasion and weak bearing capacity caused by uneven air film gaps with large middle and small two ends of the existing foil pneumatic dynamic bearing are solved.

Description

Axial clearance-variable type gas dynamic pressure bearing

Technical Field

The invention relates to the technical field of dynamic pressure bearings, in particular to an axial gap-changing type gas dynamic pressure bearing.

Background

The traditional foil gas dynamic pressure bearing consists of a top foil, an elastic foil and a bearing sleeve, wherein the rotor is in a suspension state by utilizing a dynamic pressure air film surrounded by the top foil and the rotor, and the elastic foil supports the top foil to provide damping and vibration deformation space for a rotor system, so that the rotor system has the advantages of oil-free lubrication, high rotating speed, micro-vibration permission and the like, and is widely applied to high-speed rotating mechanical equipment such as fuel cell air compressors, air circulators, blowers, micro-gas turbines, turbojet engines and the like.

The top foil and the elastic foil of the traditional foil pneumatic dynamic bearing are formed by pressing flat thin plates through a die, and the structure of the top foil and the elastic foil has axial consistency. With the increase of the speed of the rotor, the rotor drives surrounding gas to enter a convergent area surrounded by the surface of the rotor and the surface of the top foil, the gas speed is reduced, a high-pressure gas film is formed, the high-pressure gas suspends the load of the rotor, the top foil and the elastic foil move radially, and the gas film gap is gradually increased. However, the air film at the end part of the bearing is communicated with ambient gas, an air film boundary effect occurs, the air film pressure is in a parabolic distribution form with a large middle and small two ends along the axial direction of the bearing, the situation that the middle deformation is large and the axial end deformation is small occurs in the top foil and the elastic foil with axial consistency is caused, and the distance between the axial end parts of the top foil and the elastic foil and the rotor is small. When the rotor vibrates or the load is large, the situation that the end part of the top foil is worn easily occurs, and the service life of the bearing is shortened. And the high-pressure air film unevenly distributed in the axial direction can reduce the bearing capacity of the bearing.

Disclosure of Invention

Aiming at the technical defects, the application provides an axial gap-changing type gas dynamic pressure bearing, which solves the technical problems of bearing end abrasion and weak bearing capacity caused by uneven gas film gaps with large middle and small two ends of the existing foil gas dynamic pressure bearing. The technical effects which can be produced by the preferred technical scheme among the technical schemes provided by the application are described below.

In order to achieve the technical purpose, the invention provides the following technical scheme: an axial gap-changing type gas dynamic pressure bearing consists of a top foil, a bearing supporting structure and a bearing sleeve; the bearing support structure is formed by circumferentially distributing a plurality of X-shaped beams, the X-shaped beams are formed by intersecting two straight beams, the X-shaped beams distributed along the circumferential direction are sequentially overlapped, one end of each X-shaped beam is fixed in a groove of the bearing sleeve, the other end of each X-shaped beam is free, and the former X-shaped beam is supported by the latter X-shaped beam; the top foil is a circular arc-shaped thin plate, one end of the top foil is fixed on the bearing sleeve, and the other end of the top foil is freely lapped on the bearing supporting structure.

The bearing supporting structure is characterized in that a plurality of X-shaped beams are distributed along the circumferential direction and are sequentially overlapped, the X-shaped beams are cut into two crossed straight beams by processing modes such as longitudinal cutting and laser cutting of a whole sheet, a certain included angle is formed between each straight beam and the axis direction of the bearing, the distance between each straight beam and the rotor shaft is enabled to be reduced and then increased along the direction of the straight beam, one end of each X-shaped beam is fixed on the bearing sleeve, and the other end of each X-shaped beam is freely overlapped on the adjacent X-shaped beam.

The top foil is formed by bending a whole thin plate, one end of the top foil is fixed on the bearing sleeve, the other end of the top foil is freely lapped on the bearing supporting structure, the direction from the free end to the fixed end of the top foil is the same as the direction from the free end to the fixed end of the X-shaped beam, the top foil supported by a plurality of X-shaped beams deforms after being loaded, the deformation of the top foil on the straight beams adjacent to the X-shaped beams is smaller than the deformation of the top foil between the two straight beams, the concave deformation with a certain included angle with the axis of the rotor is formed, and the top foil has the effect similar to that of a herringbone notch bearing.

Preferably, the bearing support structure may be formed by a double-X-beam formed by connecting a plurality of first X-beams with a second X-beam, wherein the double-X-beams are distributed along a circumferential direction and sequentially overlapped, a former double-X-beam is supported by a latter double-X-beam, wherein a first straight beam and a fourth straight beam of the first X-beam of the former double-X-beam are respectively inserted between a third straight beam and a fourth straight beam of the latter double-X-beam, between the first straight beam and the second straight beam, or the third straight beam and the fourth straight beam of the former double-X-beam, the first straight beam and the second straight beam respectively surround a second straight beam and a third straight beam of the second X-beam of the latter double-X-beam.

Preferably, the bearing supporting structure is formed by sequentially overlapping a mesh beam structure formed by a plurality of X-shaped beams, wherein a partial X-shaped beam of the former mesh beam structure is inserted into a diamond-shaped hole of the latter mesh beam structure to form multi-node contact; the axial end part of the mesh beam structure is supported by the central part of the mesh beam structure, so that the axial end part of the mesh beam structure is in a cantilever state, the structural rigidity of the axial end part of the mesh beam structure is lower than that of the central part of the mesh beam structure, and the bearing support structure enables the top foil to obtain the same effect of axial clearance after being loaded.

The invention adopts the technology, so that compared with the prior art, the invention has the positive effects that: the invention relates to an axial gap-changing type gas dynamic pressure bearing which structurally comprises a top foil, a bearing supporting structure and a bearing sleeve; the bearing sleeve is used for fixing and supporting the top foil and the bearing supporting structure, the top foil is arc-shaped, an upper interface and a lower interface surrounding a high-pressure air film are formed on the surface of the rotor, the bearing supporting structure is composed of a plurality of straight X-shaped beams and plays a supporting role on the top foil, a certain included angle is formed between each of the two straight beams of the X-shaped beams and the axis of the round rotor, the distance between each of the straight beams and the axis of the rotor is enabled to be reduced first and then increased along the direction of the straight beam, the bearing supporting structure supports the top foil, the middle part of the bearing supporting structure is firstly contacted with the top foil, the end part of the bearing supporting structure is not contacted with the top foil, the rigidity of the bearing structure is high, the two ends of the bearing supporting structure are small, the top foil is provided with an air film gap which changes axially initially, the axial gap between the top foil and the rotor is the same, and the technical problems of bearing end abrasion and weak bearing capacity caused by uneven air film gaps between the top foil and the two ends of the existing foil air dynamic bearing are solved.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is an exploded view of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 2 is a front view of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 3 is a partial enlarged view of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 4 is a schematic structural view of an X-beam of an axial gap-variable type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 5 is a schematic view of a bearing housing of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 6 is an axial dimension change schematic diagram of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 7 is an exploded view of a modified bearing 1 of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 8 is a front view of a modified bearing 1 of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

FIG. 9 is a schematic diagram of a dual X-beam structure of an axial variable gap gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 10 is a partial view of a modified bearing 1 of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 11 is an exploded view of a modified bearing 2 of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 12 is a front view of a modified bearing 2 of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 13 is a schematic diagram of a mesh beam structure of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Fig. 14 is a partial schematic view of a modified bearing 2 of an axial variable gap type gas dynamic pressure bearing according to an embodiment of the present invention.

Wherein, the reference numerals in the figures: 1-top foil, 2-bearing support structure, 3-bearing sleeve, 21-X-beam, 201, 202-X-beam straight beam, 31-groove, 41-double X-beam, 51-mesh beam structure, 401-first X-beam, 402-second X-beam, 4101-first straight beam of double X-beam, 4102-second straight beam of double X-beam, 4103-third straight beam of double X-beam, 4104-fourth straight beam of double X-beam.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, based on the examples herein, which are within the scope of the invention as defined by the claims, will be within the scope of the invention as defined by the claims.

In the description of the present invention, unless otherwise indicated, the meaning of "a plurality of" means two or more; the terms "upper," "lower," "top," "bottom," "inner," "outer," "first," "second," and the like are used in an orientation or positional relationship based on that shown in the drawings, merely to facilitate describing the present invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

In the description of the present invention, it should be noted that, unless otherwise indicated, the term "preload" should be interpreted broadly, i.e. the thickness of the air film is not uniform in the radial direction of the bearing, for example, the bearing structure is preloaded in advance during installation, or the same effect as the preloaded in advance is achieved during operation of the bearing, and the specific meaning of the term in the present invention will be understood as appropriate to a person skilled in the art.

The axial gap-changing type gas dynamic pressure bearing provided by the embodiment of the application is described.

As shown in fig. 1 to 5, the axial variable gap type gas dynamic pressure bearing comprises a top foil (1), a bearing supporting structure (2) and a bearing sleeve (3).

As a specific embodiment, as shown in fig. 1-6, the bearing supporting structure (2) is formed by a plurality of X-beams (21) which are distributed along the circumferential direction and are sequentially overlapped, the X-beams (21) are formed by two crossed straight beams (201, 202) cut out by a whole thin plate in a linear cutting, laser cutting and other processing modes, the two straight beams (201, 202) have a certain included angle with the axial direction of the bearing, the included angle enables the distance between the straight beams (201, 202) and the rotor shaft to be firstly reduced and then increased along the direction of the straight beams (201, 202), the distance between the crossing point of the two straight beams (201, 202) and the rotor is minimum, and the external dimension L2 is larger than L1. One end of each X-shaped beam (21) is fixed in a groove (31) of the bearing sleeve (3) or fixed on the inner surface of the bearing sleeve (3) in a welding mode or the like, the other end of each X-shaped beam is freely lapped on the adjacent X-shaped beams (21), the free ends of the two straight beams (201, 202) are in a cantilever state after being supported by the adjacent X-shaped beams, and when the loaded top foil (1) presses the straight beams (201, 202) to press the straight beams of the plurality of adjacent X-shaped beams in the circumferential direction in sequence, so that the variable supporting rigidity is obtained.

As shown in fig. 1-3, the top foil (1) is formed by bending a whole thin plate, one end of the top foil is fixed on the bearing sleeve (3), the other end of the top foil is freely lapped on the bearing supporting structure (2), the direction from the free end to the fixed end of the top foil (1) is the same as the direction from the free end to the fixed end of the X-shaped beams (21), the top foil (1) supported by a plurality of X-shaped beams (21) deforms after being loaded, the deformation amount of the top foil (1) on straight beams (201, 202) of the adjacent X-shaped beams (21) is smaller than the deformation of the top foil (1) between the two straight beams (201, 202), and the top foil is deformed in a concave manner with a certain included angle with the rotor axis due to the included angle between the straight beams (201, 202), so that the top foil has the effect similar to the V-shaped notch bearing gas gathering effect.

As shown in fig. 7-10, as an alternative embodiment, the bearing support structure (2) may be formed by a double X-beam (41) formed by connecting a plurality of first X-beams (401) to a second X-beam (402), the double X-beams (41) being distributed in the circumferential direction and sequentially overlapped, the former double X-beam (41) being supported by the latter double X-beam, wherein the first straight beam (4101) and the fourth straight beam (4104) of the first X-beam (401) of the former double X-beam (41) are interposed between the third straight beam (4103) and the fourth straight beam (4104) of the latter double X-beam (41), between the first straight beam (4101) and the second straight beam (4102), or the third straight beam (4103) and the fourth straight beam (4104) of the former double X-beam (41), the first straight beam (4101) and the second straight beam (4102) respectively surround the second straight beam (402) and the third straight beam (3) of the latter double X-beam (41).

As shown in fig. 11-14, as an alternative embodiment, the bearing support structure (2) may be formed by sequentially overlapping a mesh beam structure (51) formed by a plurality of X-beams, and a single mesh beam structure is obtained by laser cutting an entire sheet, and may be regarded as being formed by connecting a plurality of X-beams distributed in the circumferential direction and the axial direction. The local X-shaped beams of the former net-shaped beam structure (51) are inserted into diamond-shaped holes of the latter net-shaped beam structure (51), and the crossed straight beams of the former local X-shaped beam are supported by the crossed straight beams of the latter local X-shaped beam to form multi-node contact; the middle part of the net beam structure (51) is supported by the fixed end of the net beam structure (51) and the latter local X-shaped beam, and the axial end part of the net beam structure (51) is supported by the central part of the net beam structure (51), so that the axial end part of the net beam structure (51) is in a cantilever state, the structural rigidity of the net beam structure is lower than that of the central part of the net beam structure (51), the technical problem that the two ends of the top foil (1) and the bearing supporting structure (2) are small after being loaded is avoided, and the same effect of axial clearance is obtained.

As an alternative embodiment, the straight beams at the local positions of the net-shaped beam structure (51) may be added or deleted during the machining process, achieving an increase or decrease of the local stiffness.

As an alternative embodiment, the X-beam (21) is a beam structure of one shape constituting the bearing support structure (2), other shapes may be used instead, such as a triangular structure, a rectangular structure, a V-shaped structure, an arc-shaped structure, etc.

As an alternative embodiment, the bearing supporting structure (2) can be formed by sequentially overlapping a plurality of X-shaped beams (21) or double X-shaped beams (41) or net-shaped beam structures (51) which are distributed in the axial direction or the circumferential direction, and the plurality of X-shaped beams (21) or double X-shaped beams (41) or net-shaped beam structures (51) can be uniformly distributed or unevenly distributed. The bearing support structure (2) may be axially or circumferentially distributed by a plurality of X-beams (21) or double X-beams (41) or mesh beam structures (51) overlapping in radial direction or overlapping in radial direction in a staggered manner.

The foregoing description is only a preferred embodiment of the present invention and is not intended to limit the present invention, but although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the technical solutions described in the foregoing embodiments, or that equivalents may be substituted for part of the technical features thereof. Any modification, equivalent replacement, variation, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (5)

1. An axial variable gap type gas dynamic pressure bearing, comprising: the bearing comprises a top foil (1), a bearing supporting structure (2) and a bearing sleeve (3); the bearing support structure (2) is formed by circumferentially distributing a plurality of X-shaped beams (21), the X-shaped beams (21) are formed by intersecting two straight beams (201, 202), the X-shaped beams (21) distributed along the circumferential direction are sequentially overlapped, one end of each X-shaped beam is fixed in a groove (31) of the bearing sleeve (3), the other end of each X-shaped beam is free, and the former X-shaped beam is supported by the latter X-shaped beam (21); the top foil (1) is a circular arc-shaped thin plate, one end of the top foil is fixed on the bearing sleeve (3), and the other end of the top foil is freely lapped on the bearing supporting structure (2).

2. The axial gap-changing type gas dynamic pressure bearing according to claim 1, wherein the bearing supporting structure (2) is formed by circumferentially distributing and sequentially overlapping a plurality of X-shaped beams (21), the X-shaped beams (21) are formed by cutting two crossed straight beams (201, 202) through a whole sheet in a linear cutting, laser cutting and other processing mode, and an included angle is formed between each straight beam (201, 202) and the axis direction of the bearing, so that the distance between each straight beam (201, 202) and a rotor shaft is reduced and increased firstly in the direction of the corresponding straight beam (201, 202), one end of each X-shaped beam (21) is fixed on the bearing sleeve (3), and the other end of each X-shaped beam is freely overlapped on the adjacent X-shaped beam (21).

3. The axial gap-changing type gas dynamic pressure bearing as claimed in claim 1, wherein said top foil (1) is formed by bending a whole thin plate, one end of said top foil is fixed on said bearing housing (3), the other end is freely lapped on said bearing supporting structure (2), the direction from the free end to the fixed end of said top foil (1) is the same as the direction from the free end to the fixed end of said X-beams (21), said top foil (1) supported by a plurality of said X-beams (21) is deformed after being loaded, the deformation of said top foil (1) between said straight beams (201, 202) adjacent to said X-beams (21) is smaller than the deformation of said top foil (1) between said two straight beams (201, 202), forming a concave deformation having a certain angle with the rotor axis, having the effect of "gas gathering" like a chevron notch bearing.

4. The axially variable gap gas dynamic pressure bearing according to claim 1, characterized in that the bearing support structure (2) may be constituted by a double X-beam (41) consisting of several first X-beams (401) connected to a second X-beam (402), the double X-beams (41) being circumferentially distributed and overlapping in sequence, the former double X-beam (41) being supported by the latter double X-beam, wherein the first straight beam (4101) and the fourth straight beam (4104) of the first X-beam (401) of the former double X-beam (41) are interposed between the third straight beam (4103) and the fourth straight beam (4104) of the latter double X-beam (41), between the first straight beam (4101) and the second straight beam (4102), or the third straight beam (4103) and the fourth beam (4104) of the former double X-beam (41041), respectively, the first straight beam (4101) and the second straight beam (4102) surrounding the third straight beam (4103) and the second straight beam (4102) of the latter double X-beam (41), respectively.

5. The axial variable gap type gas dynamic pressure bearing as claimed in claim 1, wherein the bearing supporting structure (2) can be formed by sequentially overlapping a net beam structure (51) composed of a plurality of X-beams, wherein a partial X-beam of the former net beam structure (51) is inserted into a diamond-shaped hole of the latter net beam structure (51) to form multi-node contact; the axial end part of the mesh beam structure (51) is supported by the central part of the mesh beam structure (51), so that the axial end part of the mesh beam structure (51) is in a cantilever state, the structural rigidity of the axial end part is lower than that of the central part of the mesh beam structure (51), and the bearing support structure (2) enables the top foil (1) to obtain the same effect of axial clearance after being loaded.