CN-119825825-B - Rigidity-adjustable foil pneumatic dynamic bearing

CN119825825BCN 119825825 BCN119825825 BCN 119825825BCN-119825825-B

Abstract

The application provides a rigidity-adjustable foil pneumatic dynamic bearing which comprises a top foil, a first foil, an SMA foil set, a second foil, a bearing sleeve, cooling plates and cooling plates, wherein the first foil and the second foil are composed of two longitudinal beams at the connecting end parts of V-shaped beams distributed circumferentially, the circumferential length of the V-shaped beam of the first foil is smaller than a gap between two adjacent V-shaped beams of the second foil, the V-shaped beam of the first foil is arranged between the V-shaped beams of the two second foils, the SMA foil set is composed of a first SMA foil, an electric control heating film and a second SMA foil which are sequentially overlapped and are positioned between the first foil and the second foil, the axial width of the SMA foil is smaller than the axial width of the V-shaped beams of the first foil and the second foil, the cold end of the electric control cooling plate is tightly attached to the V-shaped beams of the second foil, the hot end of the electric control cooling plate is connected with the cooling plates, the top foil provides a bearing surface of a dynamic pressure film, and the bearing sleeve supports and fixes all components. The application rapidly adjusts the elastic modulus of the SMA foil through the electric control heating film and the cooling fin, realizes the active adjustment of the rigidity of the bearing, solves the technical problem that the existing foil pneumatic dynamic pressure bearing cannot span the critical rotating speed and is unstable at the ultra-high speed, ensures that the top foil and the SMA foil set are participated in the structural deformation in the form of simply supported beams by the V-shaped beams distributed at intervals in the circumferential direction, improves the shock resistance tolerance and the durability, and generates V-shaped concave on the top foil after being loaded, thereby generating the gas gathering effect similar to that of the grooved bearing and improving the bearing capacity of the bearing.

Inventors

CAO YUANLONG
ZENG YIXING
LIU ZIZHENG
GUAN HANQING
ZHAO XUEYUAN
YU RUI
LIU WANHUI
WU YIHUA

Assignees

南华大学

Dates

Publication Date: 20260512
Application Date: 20250227

Claims (9)

1. A rigidity-adjustable foil pneumatic dynamic bearing is characterized by comprising a top foil, a first foil, a shape memory alloy foil set, a second foil, a bearing sleeve, cooling fins and cooling fins, wherein, The first foil and the second foil are composed of two longitudinal beams, wherein the two longitudinal beams are connected with the end parts of the foils through a plurality of beam structures distributed in the circumferential direction, the circumferential length of the beam structure of the first foil is smaller than the gap between the adjacent beam structures of the second foil, the first foil and the second foil are arranged between the adjacent beam structures of the second foil, and the beam structures are V-shaped beams, arc-shaped beams or straight-shaped beams; The shape memory alloy foil set is formed by sequentially superposing a first shape memory alloy foil, an electric control heating film and a second shape memory alloy foil, is positioned between the radial direction and the axial direction of the first foil and the second foil, and has an axial width smaller than that of a beam structure of the first foil and the second foil; the cold end of the cooling fin is positioned below the second foil and clings to the beam structure of the second foil, the hot end of the cooling fin clings to the cooling fin, and the cooling fin is provided with a plurality of vertical thin plates to increase the heat dissipation area; the axial length of the top foil is smaller than or equal to that of the first foil, the second foil and the bearing sleeve, the top foil provides a bearing surface of a dynamic pressure air film, and the bearing sleeve supports and fixes the top foil, the first foil, the shape memory alloy foil set, the second foil, the cooling fin and the cooling fin.
2. The adjustable stiffness foil gas dynamic pressure bearing of claim 1, wherein the axial middle position of the V-shaped beam, the arc-shaped beam or the straight-shaped beam has a circumferential length greater than that of the ends thereof, such that the middle stiffness is greater than the two-end supporting stiffness, the second foil has holes corresponding to the beam structure of the first foil in an enlarged scale at the circumferential position of the beam structure of the first foil, such that the beam structure of the first foil is deformable, and the ends of the first foil are in a cantilever state with respect to the group of shape memory alloy foils.
3. The rigidity-adjustable foil aerodynamic bearing of claim 1, wherein the electric control heating film is single or multiple, the circumferential length of the electric control heating film is equal to or smaller than that of the first shape memory alloy foil, the first shape memory alloy foil and the second shape memory alloy foil can be globally or locally heated to change the phase of the shape memory alloy material so as to change the elastic modulus of the shape memory alloy material and increase the diameter value of the shape memory alloy material to generate local preload effect, and the detachable cooling fins are circumferentially distributed in a cooling fin groove and a cooling fin groove on a bearing sleeve respectively and are used for adjusting the temperature of the shape memory alloy foil set in cooperation with the electric control heating film.
4. The rigidity-adjustable foil pneumatic dynamic pressure bearing of claim 1, wherein the top foil is of an arc-shaped or sectional structure, one end of the top foil is fixed on the bearing sleeve, the other end of the top foil is free, and the side line of the free end is arc-shaped, V-shaped or in a straight shape, wherein the arc-shaped or V-shaped direction is consistent with the rotation direction of the rotor.
5. The adjustable stiffness foil gas dynamic pressure bearing of claim 1, wherein the first and second shape memory alloy foils have circumferentially distributed shape memory alloy foil end slots at both ends thereof such that the middle stiffness is greater than the two ends stiffness, the shape memory alloy foil end slots being disposed below the beam structure of the first foil.
6. A rigidity-adjustable foil pneumatic thrust bearing is characterized by comprising a thrust top foil, a thrust first foil, a thrust shape memory alloy foil set, a thrust second foil and a thrust bearing sleeve, wherein, The thrust foil girder structure of the thrust first foil is smaller than the gap between the adjacent thrust foil girder structures of the thrust second foil in circumferential direction and is arranged between the two thrust foil girder structures of the thrust second foil, and the thrust foil girder structures are thrust foil V-shaped girders, thrust foil arc-shaped girders or thrust foil I-shaped girders; the thrust shape memory alloy foil set consists of a thrust first shape memory alloy foil, a thrust second shape memory alloy foil and a thrust electric control heating film which are the same in structure, wherein the thrust electric control heating film is arranged between the thrust first shape memory alloy foil and the thrust second shape memory alloy; The thrust top foil comprises a thrust top foil outer ring, a thrust top foil connecting beam and a thrust top foil bearing surface, wherein the outer diameter of the thrust top foil bearing surface which is circumferentially distributed is smaller than or equal to the outer diameter of the thrust foil beam structure, and the inner diameter of the thrust top foil bearing surface is larger than or equal to the inner diameter of the thrust foil beam structure; the thrust top foil, the thrust first foil, the thrust shape memory alloy foil set and the thrust second foil are fixed on the thrust bearing sleeve through the thrust foil limiting holes.
7. The rigidity-adjustable foil pneumatic thrust bearing of claim 6, wherein the two sides of the same side of the thrust foil V-shaped beam are different in circumferential width, the straight-shaped beam is arranged along the radial direction of the thrust bearing or in the horizontal and vertical directions, the specific shape of the thrust foil beam structure is set according to the pressure distribution of the thrust bearing, and the thrust second foil is provided with holes corresponding to the thrust foil beam structure with an enlarged proportion at the circumferential position of the thrust foil beam structure of the thrust first foil, so that the thrust foil beam structure can deform; the bearing is divided into a plurality of parts in the circumferential direction by a plurality of thrust foil girder structures which are distributed unevenly in the circumferential direction, and the thrust foil girder structures of the first part and the thrust foil girder structures of the second part are separated by thrust foil reserved holes.
8. The rigidity-adjustable foil aerodynamic thrust bearing of claim 6, wherein the thrust first shape memory alloy foil and the thrust second shape memory alloy foil have inner diameters larger than the inner diameter of the thrust foil girder structure and outer diameters smaller than the outer diameter of the thrust foil girder structure, and the thrust electric control heating film is a single or a plurality of circumferentially distributed, global or local heating thrust first shape memory alloy foil and thrust second shape memory alloy foil, and the elastic modulus of the thrust first shape memory alloy foil and the thrust second shape memory alloy foil is changed and the diameter value of the thrust electric control heating film is increased.
9. The variable stiffness foil aerodynamic thrust bearing of claim 7, wherein the thrust tip foil ends are arcuate or V-shaped and are configured according to a gas film pressure profile, one thrust tip foil end of the thrust tip foil is supported by the thrust foil beam structure and the other thrust tip foil end is deformed within a thrust foil preformed hole, the arcuate or V-shaped orientation of the thrust tip foil bearing surface being consistent with the direction of rotor rotation.

Description

Rigidity-adjustable foil pneumatic dynamic bearing Technical Field The invention relates to the technical field of dynamic pressure bearings, in particular to a rigidity-adjustable foil gas dynamic pressure bearing which is particularly suitable for high-speed rotating mechanical equipment, such as a fuel cell air compressor, a blower, a miniature gas turbine and the like. Background The foil dynamic pressure bearing is divided into radial bearing and thrust bearing, which is composed of top foil, elastic foil and bearing sleeve, and uses high pressure gas as carrier for supporting rotor. However, the rigidity and the rotor rigidity of the existing bearing do not change with the rotor speed, so that when the rotor speed is close to or equal to the higher-order natural frequency of the system, the vibration amplitude seriously exceeds the bearing clearance, and the critical speed cannot be crossed. In addition, the smooth top foil and the elastic structure with circumferential consistency enable the main rigidity of the bearing in the horizontal and vertical directions to be isotropic and the crossed rigidity to be antisymmetric, so that the subsynchronous instability phenomenon of the rotor occurs at high speed. The thrust bearing is used for bearing the axial force of the rotor system to restrain the axial vibration and the movement of the rotor system, however, in the prior art, the thrust bearing has insufficient bearing capacity for the axial load. Disclosure of Invention Aiming at the technical defects, the application provides the rigidity-adjustable foil pneumatic dynamic pressure bearing, which takes a shape memory alloy foil as an elastic structure of the bearing, and rapidly adjusts the elastic modulus of the shape memory alloy foil through an electric control heating film and a cooling plate, so as to realize the active adjustment of the rigidity of the bearing. In addition, the combined design of the cooling fin and the cooling fin effectively improves the heat dissipation effect of the bearing, ensures the stability of the bearing in high-speed rotation, and the top foil, the first foil, the shape memory alloy foil set and the second foil which are distributed in sequence participate in the deformation of the structure in the form of a simply supported beam, so that the bearing capacity and the durability of the bearing to impact load are improved, and meanwhile, the top foil generates a gas gathering effect similar to a grooved bearing under the support of the first foil, so that the bearing capacity of the bearing is improved. The technical effects which can be produced by the preferred technical scheme among the technical schemes provided by the application are described below. The invention provides a rigidity-adjustable foil pneumatic dynamic bearing which comprises a top foil, a first foil, a shape memory alloy foil set, a second foil, a bearing sleeve, cooling fins and radiating fins. The first foil and the second foil are composed of two longitudinal beams, wherein the two longitudinal beams are formed by connecting a plurality of beam structures distributed in the circumferential direction, the circumferential length of each beam structure of the first foil is irrelevant to the circumferential length of each beam structure of the second foil, the circumferential gaps of the beam structures of the adjacent two first foils are irrelevant to the circumferential gaps of the beam structures of the adjacent two second foils, the circumferential length of each beam structure of the first foil is smaller than the gaps of the beam structures of the adjacent two second foils, the beam structures of the second foil are arranged between the beam structures of the two second foils, the circumferential length of each beam structure of the second foil is smaller than the gaps of the beam structures of the adjacent two first foils, the axial widths of the first foil and the second foil are equal to the axial width of the top foil and are larger than the axial width of the shape memory alloy foil set, and the end parts of the first foil are in a cantilever state relative to the shape memory alloy set. The shape memory alloy foil set consists of a first shape memory alloy foil, a second shape memory alloy foil and an electric control heating film, wherein the first shape memory alloy foil, the second shape memory alloy foil and the electric control heating film have the same length, the electric control heating film is arranged between the first shape memory alloy foil and the second shape memory alloy foil, the axial width of the shape memory alloy foil set is smaller than that of a beam structure of the first foil and the second foil, the circumferential length of the electric control heating film is equal to or smaller than that of the first shape memory alloy foil, and the electric control heating film is electrified to heat the first shape memory alloy foil and the second shape memory alloy foil to