CN113969938A

CN113969938A - Bump foil assembly, foil dynamic pressure air bearing and shaft system

Info

Publication number: CN113969938A
Application number: CN202111607782.1A
Authority: CN
Inventors: 聂慧凡; 张彪; 赵俊志; 毕刘新; 侯炎恒
Original assignee: Tianjin Feixuan Technology Co ltd
Current assignee: Tianjin Feixuan Technology Co ltd
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2022-01-25
Anticipated expiration: 2041-12-27
Also published as: CN113969938B; WO2023126021A2; WO2023126021A3

Abstract

The invention provides a bump foil assembly, a foil dynamic pressure air bearing and a shaft system, wherein the bump foil assembly comprises a positioning foil and a plurality of arch wave units; a plurality of positioning grooves are formed in the positioning foil; the arch wave unit includes interconnect's first location portion and deformation portion, and first location portion offsets with location foil towards one side of bearing sleeve, and deformation portion is the arch setting, and in the deformation portion worn to locate the constant head tank, and the constant head tank did not contact with deformation portion along the both sides wall of the circumference of location foil. Compared with the traditional whole continuous wave foil structure, the wave foil assembly has the advantages that the arch wave units are separated and decoupled from each other, and the situation that the adjacent arch waves cannot move due to the fact that internal force between the adjacent arch waves is offset, and further friction damping cannot be generated is avoided. Therefore, the arch wave unit in the wave foil assembly is easier to deform and is easier to slide relative to the bearing sleeve and the top foil, the friction damping effect is stronger, and the damping performance of the foil dynamic pressure air bearing is effectively improved.

Description

Bump foil assembly, foil dynamic pressure air bearing and shaft system

Technical Field

The invention relates to the field of foil bearings, in particular to a bump foil assembly, a foil dynamic pressure air bearing and a shaft system.

Background

The foil dynamic pressure air bearing is a key supporting component of a rotating mechanical shaft system, is particularly suitable for high rotating speed, light load, high temperature, low temperature and oil-free working conditions, and mainly comprises three parts, namely a top foil, a corrugated foil and a bearing sleeve.

The bump foil is a key part for determining the performance and the reliability of the whole foil dynamic pressure air bearing, and the rotating mechanical shaft system requires the bump foil to have better bearing capacity and vibration and impact resistance. The vibration and impact resisting capacity is realized by rapidly converting mechanical energy of vibration and impact into internal energy by utilizing damping between the wave foil and the top foil and between the wave foil and the bearing sleeve. If the damping performance of the foil dynamical pressure air bearing is insufficient, the instability and even the blockage of the rotor-bearing system in the working rotating speed range are easily caused.

In the conventional foil dynamical pressure air bearing, one end of the top foil and one end of the bump foil are usually fixed on the bearing sleeve by a pinning or welding process for the sake of assembly manufacturability, and the bump foil forms a typical structure with one fixed end and one free end. The structure brings natural asymmetry to the foil hydrodynamic air bearing, so that the conditions of good damping effect at the free end and poor effect at the fixed end are caused, and finally the damping performance of the foil hydrodynamic air bearing is insufficient.

Disclosure of Invention

In order to solve the problems of the prior art, it is an object of the present invention to provide a bump foil assembly.

The invention provides the following technical scheme:

a bump foil assembly comprises a positioning foil and a plurality of bump units;

a plurality of positioning grooves are formed in the positioning foil sheet, are arranged along the circumferential direction of the positioning foil sheet and respectively correspond to the arch wave units;

the arch wave unit comprises a first positioning part and a deformation part which are connected with each other, the first positioning part is abutted to one side, facing the bearing sleeve, of the positioning foil, the deformation part is arranged in an arch shape, the deformation part penetrates through the positioning groove, and the positioning groove is arranged along two side walls of the circumferential direction of the positioning foil and is not in contact with the deformation part.

As a further alternative to the wave foil assembly, a side of the deformation portion away from the first positioning portion overlaps the first positioning portion of the adjacent arch wave unit.

As a further alternative to the bump foil assembly, a side of the deformation portion away from the first positioning portion overlaps a side of the positioning foil facing away from the bearing sleeve.

As a further alternative to the bump foil assembly, a second positioning portion is provided on a side of the deformation portion away from the first positioning portion, and the second positioning portion is located on a side of the first positioning portion of the adjacent bow wave unit facing away from the positioning foil.

As a further optional solution to the bump foil assembly, two side walls of the positioning groove along the axial direction of the positioning foil do not abut against the deformation portion to avoid the deformation portion from being stuck.

As a further alternative to the bump foil assembly, the positioning grooves are provided with a plurality of groups in the axial direction of the positioning foil.

It is another object of the present invention to provide a foil dynamical pressure air bearing.

The invention provides the following technical scheme:

a foil dynamical pressure air bearing comprises a top foil, a bearing sleeve and the bump foil assembly;

the dome of the deformation portion abuts against the top foil, and the first positioning portion abuts against the bearing sleeve.

It is a further object of the present invention to provide a shafting.

The invention provides the following technical scheme:

a shaft system comprises the foil dynamical pressure air bearing.

The embodiment of the invention has the following beneficial effects:

and the first positioning part of the arch wave unit is abutted against one side of the positioning foil piece facing the bearing sleeve, and the deformation part passes through the positioning groove, so that the arch wave unit is limited in the circumferential direction and the axial direction of the positioning foil piece by the positioning foil piece. Meanwhile, the two side walls of the positioning groove along the circumferential direction of the positioning foil are not in contact with the deformation part, and when the pressure applied to the deformation part changes, the whole arch wave unit can freely move along the two ends of the positioning foil along the circumferential direction to generate friction. Compared with the traditional whole continuous wave foil structure, the wave foil assembly has the advantages that the arch wave units are separated and decoupled from each other, and the situation that the adjacent arch waves cannot move due to the fact that internal force between the adjacent arch waves is offset, and further friction damping cannot be generated is avoided. Therefore, the arch wave unit in the wave foil assembly is easier to deform and is easier to slide relative to the bearing sleeve and the top foil, the friction damping effect is stronger, and the damping performance of the foil dynamic pressure air bearing is effectively improved.

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible and comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram showing the overall structure of a foil dynamical pressure air bearing in the prior art;

FIG. 2 is a schematic diagram illustrating a prior art foil dynamical pressure air bearing after being expanded in a circumferential direction;

FIG. 3 is a schematic diagram showing deformation of a single arch wave after being compressed in the prior art;

FIG. 4 is a schematic diagram showing deformation of two adjacent arch waves after being compressed in the prior art;

FIG. 5 is a diagram illustrating a state where a bearing load is located at a free end of a bump foil in the related art;

FIG. 6 is a diagram illustrating a state where a bearing load is located at a fixed end of a bump foil in the related art;

FIG. 7 is a schematic view showing a structure of a press mold in the related art;

fig. 8 is a schematic view showing the overall structure of a bump foil assembly provided in embodiment 1 of the present invention;

fig. 9 is a schematic structural diagram of a wave foil assembly provided in embodiment 1 of the present invention from another view angle;

FIG. 10 shows an enlarged schematic view at A in FIG. 9;

fig. 11 is a schematic structural diagram illustrating a bow wave unit in a wave foil assembly according to embodiment 1 of the present invention;

fig. 12 is a schematic view showing an overall structure of a foil dynamical pressure air bearing provided in embodiment 1 of the present invention;

FIG. 13 is a schematic view showing a part of a circumferentially expanded foil dynamical pressure air bearing according to embodiment 1 of the present invention;

fig. 14 is a schematic structural diagram illustrating a forming mold used in a manufacturing process of a foil dynamical pressure air bearing according to embodiment 1 of the present invention;

FIG. 15 is a schematic diagram illustrating the relationship between the positioning foil and the crowning units in a foil dynamical pressure air bearing according to embodiment 2 of the present invention;

fig. 16 is a schematic diagram illustrating a fitting relationship between a positioning foil and an arch wave unit in a foil dynamical pressure air bearing according to embodiment 3 of the present invention.

Description of the main element symbols:

100-wave foil assembly; 110-positioning the foil; 111-a positioning slot; 112-a connecting portion; 120-an arch wave unit; 121-a first positioning portion; 122-a deformation; 123-a second positioning section; 200-top foil; 210-a mounting portion; 300-a bearing sleeve; 400-wave foil; 500-a stamping die; 600-forming die.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the templates herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The rigidity and damping of the foil dynamical pressure air bearing are composed of two parts: air film stiffness and damping, foil structure stiffness and frictional damping. In general, foil structural stiffness and frictional damping account for a major portion of the overall foil hydrodynamic air bearing.

Referring to fig. 1, the conventional foil hydrodynamic air bearing includes a top foil 200, a bump foil 400 and a bearing sleeve 300, wherein one end of the top foil 200 and one end of the bump foil 400 are inserted into an inner wall of the bearing sleeve 300 and are fixed to the bearing sleeve 300 by pins via a pin key, and a rotating shaft is enveloped by the top foil 200. Wherein the top foil 200 and the bump foil 400 form a first friction pair and the bump foil 400 and the bearing sleeve 300 form a second friction pair.

When the conventional foil dynamical pressure air bearing works, an air film is formed between the rotating shaft and the top foil 200. The air film pressure is also greater for the areas of the top foil 200 that are mainly subjected to the bearing load. The friction damping means that the top foil 200 presses the wave foil 400 to deform under the action of the air film pressure, so that tiny relative motions are generated between the top foil 200 and the wave foil 400 and between the wave foil 400 and the bearing sleeve 300 to form friction, and kinetic energy is converted into internal energy by utilizing the friction force to do work. The larger the power of the friction force acting is, the better the friction damping effect is, and the higher the speed of consuming kinetic energy is, so that the vibration impact in the rotating mechanical shafting can be effectively inhibited.

Referring to fig. 2, in order to more intuitively represent the stress condition between the structures of the conventional foil dynamical pressure air bearing, the conventional foil dynamical pressure air bearing is expanded along the circumferential direction. The wave foil 400 has a plurality of arch waves B1\ B2\ a. \ Bi-1\ Bi +1\ a. \\ Bn with similar shapes, wherein the arch wave B1 is fixed with the bearing sleeve 300 as a fixed end, and the arch wave Bn is freely stretched along the circumferential direction of the foil hydrodynamic air bearing as a free end.

Referring to FIG. 3, the single bow wave Bi (1. ltoreq. i. ltoreq. n) is subjected to a force analysis by neglecting the friction between the top foil 200 and the wave foil 400. The solid line represents the bow wave before deformation and the dashed line represents the bow wave after deformation. Under the action of the air film pressure P, the top of the arch wave Bi can be sunken downwards, and horizontal thrust is generated on the two bottoms of the arch wave Bi. When the horizontal thrust force applied to the two bottoms of the arch wave Bi is greater than the friction force between the arch wave Bi and the bearing sleeve 300, the two bottoms of the arch wave Bi respectively move to the two sides along the circumferential direction of the foil hydrodynamic air bearing.

Referring to fig. 4, the two adjacent arch waves Bi and Bi +1 are subjected to stress analysis by neglecting the friction between the top foil 200 and the wave foil 400. The solid line represents the bow wave before deformation and the dashed line represents the bow wave after deformation. Under the action of the same air film pressure P, the tops of the arch waves Bi and Bi +1 simultaneously sink downwards, and the same horizontal thrust is generated on the two bottoms of the arch waves Bi and the two bottoms of the arch waves Bi +1 respectively.

On the one hand, when the horizontal thrust force applied to the right bottom of the bow wave Bi and the left bottom of the bow wave Bi +1 are respectively greater than the friction force between the horizontal thrust force and the bearing sleeve 300, the right bottom of the bow wave Bi and the left bottom of the bow wave Bi +1 move relative to the bearing sleeve 300, and friction is generated. On the other hand, the horizontal thrusts applied to the left bottom of the bow wave Bi and the right bottom of the bow wave Bi +1 cancel each other out, and the resultant force applied to the two as a whole is zero, which is not enough to overcome the friction force with the bearing sleeve 300, so that the left bottom of the bow wave Bi and the right bottom of the bow wave Bi +1 cannot move relative to the bearing sleeve 300, and thus the friction damping cannot be contributed.

In the whole area acted by the air film pressure P, the horizontal thrust of the left bottom of the ith arch wave Bi acts on the right bottom of the (i + 1) th arch wave Bi +1, and the structure internal force is used for preventing the two adjacent arch waves Bi and Bi +1 from freely moving along the pitch direction of the wave foil 400. Even in some cases, the resultant force of the right bottom horizontal thrust of the i +1 th bow wave Bi +1 and the left bottom horizontal thrust of the i-th bow wave Bi is small, and the frictional force with the bearing sleeve 300 cannot be overcome. At this time, the bump foil 400 and the bearing sleeve 300 are relatively stationary, and the bump foil 400 and the top foil 200 are relatively stationary, so that all the frictional forces do not work, consume no kinetic energy, and contribute no damping.

In short, in the region acted by the air film pressure P, the arch waves Bi-1, Bi and Bi +1 are mutually constrained, so that the possibility of freely moving towards two ends along the circumferential direction of the foil dynamic pressure air bearing is prevented, and the energy consumption caused by relative movement to generate friction damping is not facilitated.

Referring to fig. 5 and 6 together, from the perspective of the entire bump foil 400, the gas film pressure varies from place to place due to the varying area of the top foil 200 that is primarily subject to the bearing load.

When the shaft carries a load close to the free end of the wave foil 400, the arch wave Bi +1 on the right side of the load region is far from the fixed end, and the right end of the arch wave Bi +1 is substantially in a free state. Under the action of the air film pressure P, deformation of all loaded arch waves is relatively easy, the structural rigidity of the foil is low, relative movement is easy to occur between the wave foil 400 and the top foil 200 and between the wave foil 400 and the bearing sleeve 300, and the friction damping effect is strong.

However, when the shaft carries the load close to the fixed end of the bump foil 400, the foil structure stiffness increases throughout the load zone as movement to the right is restricted due to the pinned key at the right end of the bow wave B1. In addition, since the bow wave B1 can only move to the left through the bottom of the left side, the bow wave B1 inevitably blocks the bow wave B2 from moving to the right, and so on, the bow wave B2 also blocks the bow wave B3. In particular, when the air film pressure P acting on the bow wave Bi is sufficiently large, the bow wave between the bow wave B1 and the bow wave Bi will not be able to move at all. At the moment, the first friction pair and the second friction pair cannot effectively apply work through friction force to consume the impact vibration energy of the rotating shaft, so that the friction damping effect of the foil hydrodynamic air bearing is poor, the rotating speed of the rotating shaft cannot be increased finally, and the bearing capacity of the foil hydrodynamic air bearing cannot be improved.

Referring to fig. 7, in addition to the above-mentioned defects, when the conventional bump foil 400 of the foil dynamic pressure air bearing is processed, a whole strip is generally used as a raw material, and a stamping die 500 is used to stamp a whole piece of bump foil 400 in which the arch waves are sequentially connected. Such a one-piece continuous wave foil 400 structure requires the size of the stamping die 500 to be larger than the developed area of the bearing sleeve 300, and therefore requires the stamping die 500 to be made larger, and also requires high precision of form and position tolerance of the stamping die 500, resulting in high cost of the stamping die 500.

Furthermore, it is required that a single continuous piece of the wave foil 400 is stamped and formed at a time, each bow wave of the wave foil 400 is completely formed and does not rebound after the forming. The process requires a matched punch press with enough capacity, the volume of the punch press is increased, and the investment cost is increased. Because the material is a strip material, when the size of the bearing is large, the size of the arch wave formed by stamping the whole wave foil 400 is not easy to detect, and is easily influenced by the flatness of the whole wave foil 400, so that the detection cost is increased.

In a word, the existing processing technology of the continuous one-piece wave foil 400 structure has extremely high requirements on equipment, a stamping die 500 and a tool, the research and development and manufacturing costs are increased, and the production control and quality control costs are improved.

Example 1

Referring to fig. 8 and 9, the present embodiment provides a bump foil assembly 100 applied to a foil dynamical pressure air bearing, and cooperating with a top foil 200 and a bearing sleeve 300 of the foil dynamical pressure air bearing. The bump foil assembly 100 comprises a positioning foil 110 and a plurality of bump units 120, wherein the bump units 120 are respectively in mutual laminated contact with the positioning foil 110 and can independently deform when stressed.

In particular, the cross-section of the positioning foil 110 is arc-shaped, the corresponding central angle being slightly less than 360 °. One end of the positioning foil 110 in the circumferential direction is integrally formed with a connection part 112 for fixedly connecting with the bearing sleeve 300. In addition, the positioning foil 110 is provided with a plurality of positioning grooves 111, and the positioning grooves 111 are distributed along the circumferential direction of the positioning foil 110.

Referring to fig. 10 and 11, in particular, the number of the arcuate wave units 120 is the same as that of the positioning slots 111, and the arcuate wave units and the positioning slots are in one-to-one correspondence. The bow wave unit 120 is composed of a first positioning portion 121 and a deformation portion 122, and the first positioning portion 121 and the deformation portion 122 are arranged in the circumferential direction of the positioning foil 110.

The first positioning portion 121 abuts against an outer sidewall of the positioning foil 110, and the deformation portion 122 is configured to be arched and is inserted into the positioning groove 111. One side arch of the deformation portion 122 is integrally formed with the first positioning portion 121, the arch of the deformation portion 122 is located at the inner periphery of the positioning foil 110, and the other side arch of the deformation portion 122 overlaps the first positioning portion 121 of the adjacent bow wave unit 120.

Particularly, the two side walls of the positioning groove 111 along the circumferential direction of the positioning foil 110 are not in contact with the deformation portion 122, and when the pressure applied to the deformation portion 122 changes, the entire arch wave unit 120 can move freely along the circumferential direction of the positioning foil 110, and friction occurs. In addition, two side walls of the positioning groove 111 along the axial direction of the positioning foil 110 do not abut against the deformation portion 122, so that the deformation portion 122 is prevented from being clamped in the deformation process.

On the premise of not obstructing the free movement of the arch wave unit 120, the positioning foil 110 limits the arch wave unit 120 along its own circumferential direction and also limits the arch wave unit 120 along its own axial direction, so that the deformation portion 122 of the arch wave unit 120 is stabilized in the positioning groove 111.

Referring to fig. 8 again, in an embodiment of the present invention, a plurality of sets of positioning grooves 111 are disposed along an axial direction of the positioning foil 110, the positioning grooves 111 of each set are arranged along the axial direction of the positioning foil 110, and the arcuate wave unit 120 is disposed corresponding to the positioning grooves 111.

In another embodiment of this embodiment, the positioning grooves 111 are provided with only one set in the axial direction of the positioning foil 110, and the arch wave unit 120 is an elongated arch wave with a whole length and a narrow width in the axial direction of the positioning foil 110.

In short, the wave foil assembly 100 is divided into the positioning foil 110 and the plurality of arch wave units 120, the plurality of arch wave units 120 are respectively connected to the positioning foil 110, and both ends of the arch wave units 120 along the circumferential direction of the positioning foil 110 can freely move, so that each arch wave unit 120 can independently deform. Compared with the conventional integral continuous wave foil 400 structure, the arch wave units 120 in the wave foil assembly 100 are separated and decoupled from each other, and the situation that the internal forces between adjacent arch waves are offset to cause the arch waves to be incapable of moving and further cause the frictional damping to be incapable of being generated cannot occur. Therefore, the wave unit 120 in the wave foil assembly 100 is easier to deform and slide relative to the bearing sleeve 300 and the top foil 200, the friction damping effect is stronger, and the damping performance of the foil dynamical pressure air bearing is effectively improved.

Referring to fig. 12, the present embodiment further provides a foil dynamical pressure air bearing, and more particularly, a low-cost, isotropic single-arch wave laminated strong friction damping foil dynamical pressure air bearing, which includes a top foil 200, a bearing sleeve 300 and the above-mentioned wave foil assembly 100.

Specifically, the bearing sleeve 300 has a cylindrical shape as a mounting base of the top foil 200 and the bump foil assembly 100.

Specifically, the outer diameter of the positioning foil 110 is smaller than the inner diameter of the bearing sleeve 300, and the connection portion 112 at one end of the positioning foil 110 is inserted into the inner hole of the bearing sleeve 300 and is fixedly connected with the bearing sleeve 300 by a pinning key. The first positioning portion 121 is sandwiched between the positioning foil 110 and the bearing sleeve 300, one side of the first positioning portion 121 abuts against the positioning foil 110, and the other side abuts against the inner hole of the bearing sleeve 300. The crowning unit 120 cannot move in the radial direction of the foil dynamical pressure air bearing, limited by the positioning foil 110 and the bearing sleeve 300.

Specifically, the top foil 200 is located at the inner periphery of the bump foil assembly 100, and the outer diameter of the top foil 200 is smaller than the inner diameter of the positioning foil 110, and the outer side wall of the top foil 200 abuts against the dome of each deformation portion 122. One end of the top foil 200 along the circumferential direction is integrally formed with a mounting portion 210, and the mounting portion 210 is inserted into an inner hole of the bearing sleeve 300 and is also fixedly connected with the bearing sleeve 300 by a pinning key.

Compared with the prior art, the foil dynamical pressure air bearing has the advantages that:

(1) in the foil dynamical pressure air bearing, every two adjacent arch wave units 120 are not continuous and integrated, the deformation part 122 of one arch wave unit 120 is pressed against the first positioning part 121 of the other arch wave unit 120, and the two arch wave units have only friction force along the circumferential direction of the foil dynamical pressure air bearing, so that the situation that the arch wave and the adjacent part have no relative displacement due to the cancellation of the internal force of the adjacent arch waves in the conventional continuous wave foil 400 does not exist.

Under the action of the air film pressure, the deformation portion 122 and the first positioning portion 121 of each arch wave unit 120 can freely move along the circumferential direction of the foil hydrodynamic air bearing, and two adjacent arch wave units 120 are not obstructed, so that the situation that the other arch wave units 120 cannot move due to the fact that the certain arch wave unit 120 is subjected to overlarge friction force and cannot move is avoided.

In short, since the individual bow wave units 120 are disconnected from each other, the above-described wave foil assembly 100 is more easily deformed than the conventional wave foil 400 under the same load, and relative displacement between the wave foil assembly 100 and the top foil 200 and between the wave foil assembly 100 and the bearing sleeve 300 is more easily generated, contributing to greater frictional damping. Therefore, the foil dynamic pressure air bearing is more suitable for high-speed light-load occasions where high-speed instability is easy to occur, and the effect is better.

(2) The foil dynamical pressure air bearing limits all the arch wave units 120 axially and circumferentially by the combined action of the positioning foil 110 and the inner hole surface of the bearing sleeve 300. Each of the arcuate wave units 120 is installed at the positioning groove 111 of the positioning foil 110, ensuring that each of the arcuate wave units 120 can be freely deformed in the radial and circumferential directions of the foil dynamical pressure air bearing without interfering with each other, and ensuring that the foil dynamical pressure air bearing has the same rigidity and ideal frictional damping in each circumferential position.

Therefore, no matter whether the bearing load acts on the fixed end or the free end of the positioning foil 110, the stiffness and the frictional damping effect of the bump foil assembly 100 are not greatly different, and there is an advantage of isotropy. The above-described foil dynamical pressure air bearing structure is more suitable than the prior art when the bearing load direction is unstable or is subjected to a large dynamic load.

(3) Referring to fig. 13, in order to more intuitively embody the matching between the structures of the foil dynamical air bearing, the foil dynamical air bearing is spread out in the circumferential direction.

In the foil hydrodynamic air bearing, the dome of the deformation portion 122 and the top foil 200 form a third friction pair, the abutment of the deformation portion 122 on the side away from the first positioning portion 121 and the first positioning portion 121 of the adjacent arch wave unit 120 form a fourth friction pair, the first positioning portion 121 and the bearing sleeve 300 form a fifth friction pair, and the first positioning portion 121 and the positioning foil 110 form a sixth friction pair.

The fourth friction pair and the sixth friction pair are not provided by the conventional foil dynamic pressure air bearing. Particularly, in the fourth friction pair, the moving direction of the rib of the deformation portion 122 is opposite to the moving direction of the first positioning portion 121 of the adjacent bow wave unit 120, the relative moving distance between the rib and the first positioning portion is significantly increased, the frictional damping performance is significantly enhanced, and the stability of the system is greatly improved.

When the foil dynamical pressure air bearing works, each arch wave unit 120 can be freely deformed under the action of external load, the friction force of the four friction pairs acts to generate friction damping, the condition that adjacent arch waves in the existing foil dynamical pressure bearing are restrained and blocked cannot occur, and the friction damping performance is better.

(4) Referring to fig. 14, the axial and circumferential dimensions of the single arch wave unit 120 are much smaller than those of the conventional continuous wave foil 400, and the single arch wave unit can be formed by stamping one by one during the processing, so that the required press and the forming die 600 can be easily obtained at a lower price, and the stamping cost is reduced. Meanwhile, because the size of the arch wave unit 120 is very small, a heat treatment tool close to the three-dimensional size of the bearing is not needed during heat treatment, so that the furnace loading amount of heat treatment can be increased, and the heat treatment cost is further reduced. Moreover, because the size of the arch wave unit 120 is small and the structure is single, the detection is very convenient, and the detection cost is reduced.

The foil dynamical pressure air bearing is manufactured by the following steps:

in the first step, a positioning foil 110 having a plurality of positioning grooves 111 in the middle is manufactured by a chemical etching method, and the positioning foil 110 is rolled according to a predetermined diameter.

In the second step, the arch wave units 120 are punched one by using the forming die 600, and then are subjected to heat treatment for standby.

And thirdly, performing rolling treatment on the top foil 200 according to the set diameter, and performing heat treatment for later use.

Fourthly, all the arch wave units 120 sequentially pass through the positioning grooves 111 to form the wave foil assembly 100. During the assembly process, the positioning foil 110 is ensured to be pressed on the first positioning portion 121 of the arch wave unit 120, and the deformation portion 122 of the arch wave unit 120 is ensured to be pressed on the first positioning portion 121 of the adjacent arch wave unit 120. Further, the fitting is performed from the bottom to the upper portion along the positioning groove 111 one by one.

And fifthly, each time the arch wave unit 120 is assembled in one circle of the positioning grooves 111, the wave foil assembly 100 with the corresponding height is installed in the bearing sleeve 300 and fixed, and the first positioning parts 121 of the arch wave unit 120 are ensured to be attached to the inner hole surface of the bearing sleeve 300. Finally, the top foil 200 is installed in the bearing sleeve 300 and fixed to form the foil dynamical pressure air bearing.

The embodiment also provides a shaft system which comprises a bearing seat, a rotating shaft and the foil dynamical pressure air bearing. The bearing sleeve 300 is mounted on the bearing housing, and the rotating shaft is inserted into the top foil 200.

Example 2

Referring to fig. 15, the difference from embodiment 1 is that the arch foot of the deformation portion 122 away from the first positioning portion 121 is overlapped on the positioning foil 110 and abuts against the inner sidewall of the positioning foil 110.

At this time, the fourth friction pair is composed of the rib and the positioning foil 110 on the side of the deformation portion 122 away from the first positioning portion 121. Since only the rib of the deformed portion 122 moves and the positioning foil 110 does not move, the frictional damping performance of the fourth friction pair is reduced compared to embodiment 1.

Example 3

Referring to fig. 16, the difference from embodiment 1 is that the arch wave unit 120 is composed of a first positioning portion 121, a deformation portion 122, and a second positioning portion 123.

Specifically, the deformation portion 122 is still provided with an arch shape, and the first positioning portion 121 and the second positioning portion 123 are respectively integrally formed with two arch feet of the deformation portion 122. The second positioning portion 123 is located on a side of the first positioning portion 121 of the adjacent bow wave unit 120, which faces away from the positioning foil 110, in other words, the first positioning portion 121 abuts against the inner hole of the bearing sleeve 300 through the second positioning portion 123 of the adjacent bow wave unit 120.

At this time, the fourth friction pair is composed of the first positioning portion 121 and the second positioning portion 123 of two adjacent bow wave units 120, and the fifth friction pair is composed of the second positioning portion 123 and the bearing sleeve 300.

In all examples shown and described herein, any particular value should be construed as merely exemplary, and not as a limitation, and thus other examples of example embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The above examples are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims

1. A bump foil assembly comprising a positioning foil and a plurality of bow wave units;

2. The foil assembly of claim 1, wherein a side of the deformation portion remote from the first positioning portion overlaps the first positioning portion of the adjacent bow wave unit.

3. The bump foil assembly of claim 1, wherein a side of the deformation remote from the first positioning portion is lapped on a side of the positioning foil facing away from the bearing sleeve.

4. The bump foil assembly according to claim 1, wherein a side of the deformation portion away from the first positioning portion is provided with a second positioning portion, and the second positioning portion is located on a side of the first positioning portion of the adjacent bow wave unit facing away from the positioning foil.

5. The bump foil assembly according to any one of claims 1 to 4, wherein both side walls of the positioning groove in the axial direction of the positioning foil do not abut against the deformation portion to prevent the deformation portion from being caught.

6. The bump foil assembly of claim 5, wherein the positioning grooves are provided in plural sets in an axial direction of the positioning foil.

7. A foil hydrodynamic air bearing comprising a top foil, a bearing sleeve and a bump foil assembly according to any one of claims 1 to 6;

8. A shaft assembly comprising the foil dynamical pressure air bearing of claim 7.